#include "bindings.h"
#include "config.h"
+#include "cgroup_fuse.h"
#include "cgroups/cgroup.h"
#include "cgroups/cgroup_utils.h"
#include "memory_utils.h"
return NULL;
}
-static int is_dir(const char *path, int fd)
-{
- struct stat statbuf;
- int ret = fstatat(fd, path, &statbuf, fd);
- if (ret == 0 && S_ISDIR(statbuf.st_mode))
- return 1;
- return 0;
-}
-
-static bool write_string(const char *fnam, const char *string, int fd)
-{
- FILE *f;
- size_t len, ret;
-
- f = fdopen(fd, "w");
- if (!f)
- return false;
-
- len = strlen(string);
- ret = fwrite(string, 1, len, f);
- if (ret != len) {
- lxcfs_error("%s - Error writing \"%s\" to \"%s\"\n",
- strerror(errno), string, fnam);
- fclose(f);
- return false;
- }
-
- if (fclose(f) < 0) {
- lxcfs_error("%s - Failed to close \"%s\"\n", strerror(errno), fnam);
- return false;
- }
-
- return true;
-}
-
struct cgfs_files {
char *name;
uint32_t uid, gid;
}
}
-bool cgfs_set_value(const char *controller, const char *cgroup, const char *file,
- const char *value)
+bool cgfs_param_exist(const char *controller, const char *cgroup, const char *file)
{
- int ret, fd, cfd;
+ int ret, cfd;
size_t len;
char *fnam;
if (ret < 0 || (size_t)ret >= len)
return false;
- fd = openat(cfd, fnam, O_WRONLY);
- if (fd < 0)
- return false;
-
- return write_string(fnam, value, fd);
+ return (faccessat(cfd, fnam, F_OK, 0) == 0);
}
-// Chown all the files in the cgroup directory. We do this when we create
-// a cgroup on behalf of a user.
-static void chown_all_cgroup_files(const char *dirname, uid_t uid, gid_t gid, int fd)
-{
- struct dirent *direntp;
- char path[MAXPATHLEN];
- size_t len;
- DIR *d;
- int fd1, ret;
+#define SEND_CREDS_OK 0
+#define SEND_CREDS_NOTSK 1
+#define SEND_CREDS_FAIL 2
+static bool recv_creds(int sock, struct ucred *cred, char *v);
+static int wait_for_pid(pid_t pid);
+static int send_creds(int sock, struct ucred *cred, char v, bool pingfirst);
+static int send_creds_clone_wrapper(void *arg);
- len = strlen(dirname);
- if (len >= MAXPATHLEN) {
- lxcfs_error("Pathname too long: %s\n", dirname);
- return;
- }
+/*
+ * clone a task which switches to @task's namespace and writes '1'.
+ * over a unix sock so we can read the task's reaper's pid in our
+ * namespace
+ *
+ * Note: glibc's fork() does not respect pidns, which can lead to failed
+ * assertions inside glibc (and thus failed forks) if the child's pid in
+ * the pidns and the parent pid outside are identical. Using clone prevents
+ * this issue.
+ */
+static void write_task_init_pid_exit(int sock, pid_t target)
+{
+ char fnam[100];
+ pid_t pid;
+ int fd, ret;
+ size_t stack_size = sysconf(_SC_PAGESIZE);
+ void *stack = alloca(stack_size);
- fd1 = openat(fd, dirname, O_DIRECTORY);
- if (fd1 < 0)
- return;
+ ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", (int)target);
+ if (ret < 0 || ret >= sizeof(fnam))
+ _exit(1);
- d = fdopendir(fd1);
- if (!d) {
- lxcfs_error("Failed to open %s\n", dirname);
- return;
+ fd = open(fnam, O_RDONLY);
+ if (fd < 0) {
+ perror("write_task_init_pid_exit open of ns/pid");
+ _exit(1);
}
-
- while ((direntp = readdir(d))) {
- if (!strcmp(direntp->d_name, ".") || !strcmp(direntp->d_name, ".."))
- continue;
- ret = snprintf(path, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
- if (ret < 0 || ret >= MAXPATHLEN) {
- lxcfs_error("Pathname too long under %s\n", dirname);
- continue;
- }
- if (fchownat(fd, path, uid, gid, 0) < 0)
- lxcfs_error("Failed to chown file %s to %u:%u", path, uid, gid);
+ if (setns(fd, 0)) {
+ perror("write_task_init_pid_exit setns 1");
+ close(fd);
+ _exit(1);
+ }
+ pid = clone(send_creds_clone_wrapper, stack + stack_size, SIGCHLD, &sock);
+ if (pid < 0)
+ _exit(1);
+ if (pid != 0) {
+ if (!wait_for_pid(pid))
+ _exit(1);
+ _exit(0);
}
- closedir(d);
}
-int cgfs_create(const char *controller, const char *cg, uid_t uid, gid_t gid)
-{
- int cfd;
- size_t len;
- char *dirnam;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return -EINVAL;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cg + \0
- */
- len = strlen(cg) + 2;
- dirnam = alloca(len);
- snprintf(dirnam, len, "%s%s", dot_or_empty(cg), cg);
-
- if (mkdirat(cfd, dirnam, 0755) < 0)
- return -errno;
-
- if (uid == 0 && gid == 0)
- return 0;
-
- if (fchownat(cfd, dirnam, uid, gid, 0) < 0)
- return -errno;
-
- chown_all_cgroup_files(dirnam, uid, gid, cfd);
+static int send_creds_clone_wrapper(void *arg) {
+ struct ucred cred;
+ char v;
+ int sock = *(int *)arg;
+ /* we are the child */
+ cred.uid = 0;
+ cred.gid = 0;
+ cred.pid = 1;
+ v = '1';
+ if (send_creds(sock, &cred, v, true) != SEND_CREDS_OK)
+ return 1;
return 0;
}
-static bool recursive_rmdir(const char *dirname, int fd, const int cfd)
+static pid_t get_init_pid_for_task(pid_t task)
{
- struct dirent *direntp;
- DIR *dir;
- bool ret = false;
- char pathname[MAXPATHLEN];
- int dupfd;
-
- dupfd = dup(fd); // fdopendir() does bad things once it uses an fd.
- if (dupfd < 0)
- return false;
-
- dir = fdopendir(dupfd);
- if (!dir) {
- lxcfs_debug("Failed to open %s: %s.\n", dirname, strerror(errno));
- close(dupfd);
- return false;
- }
-
- while ((direntp = readdir(dir))) {
- struct stat mystat;
- int rc;
-
- if (!strcmp(direntp->d_name, ".") ||
- !strcmp(direntp->d_name, ".."))
- continue;
-
- rc = snprintf(pathname, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
- if (rc < 0 || rc >= MAXPATHLEN) {
- lxcfs_error("%s\n", "Pathname too long.");
- continue;
- }
-
- rc = fstatat(cfd, pathname, &mystat, AT_SYMLINK_NOFOLLOW);
- if (rc) {
- lxcfs_debug("Failed to stat %s: %s.\n", pathname, strerror(errno));
- continue;
- }
- if (S_ISDIR(mystat.st_mode))
- if (!recursive_rmdir(pathname, fd, cfd))
- lxcfs_debug("Error removing %s.\n", pathname);
- }
+ int sock[2];
+ pid_t pid;
+ pid_t ret = -1;
+ char v = '0';
+ struct ucred cred;
- ret = true;
- if (closedir(dir) < 0) {
- lxcfs_error("Failed to close directory %s: %s\n", dirname, strerror(errno));
- ret = false;
+ if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
+ perror("socketpair");
+ return -1;
}
- if (unlinkat(cfd, dirname, AT_REMOVEDIR) < 0) {
- lxcfs_debug("Failed to delete %s: %s.\n", dirname, strerror(errno));
- ret = false;
+ pid = fork();
+ if (pid < 0)
+ goto out;
+ if (!pid) {
+ close(sock[1]);
+ write_task_init_pid_exit(sock[0], task);
+ _exit(0);
}
- close(dupfd);
+ if (!recv_creds(sock[1], &cred, &v))
+ goto out;
+ ret = cred.pid;
+out:
+ close(sock[0]);
+ close(sock[1]);
+ if (pid > 0)
+ wait_for_pid(pid);
return ret;
}
-bool cgfs_remove(const char *controller, const char *cg)
+pid_t lookup_initpid_in_store(pid_t qpid)
{
- int fd, cfd;
- size_t len;
- char *dirnam;
- bool bret;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cg + \0
- */
- len = strlen(cg) + 2;
- dirnam = alloca(len);
- snprintf(dirnam, len, "%s%s", dot_or_empty(cg), cg);
+ pid_t answer = 0;
+ struct stat sb;
+ struct pidns_init_store *e;
+ char fnam[100];
- fd = openat(cfd, dirnam, O_DIRECTORY);
- if (fd < 0)
- return false;
+ snprintf(fnam, 100, "/proc/%d/ns/pid", qpid);
+ store_lock();
+ if (stat(fnam, &sb) < 0)
+ goto out;
+ e = lookup_verify_initpid(&sb);
+ if (e) {
+ answer = e->initpid;
+ goto out;
+ }
+ answer = get_init_pid_for_task(qpid);
+ if (answer > 0)
+ save_initpid(&sb, answer);
- bret = recursive_rmdir(dirnam, fd, cfd);
- close(fd);
- return bret;
+out:
+ /* we prune at end in case we are returning
+ * the value we were about to return */
+ prune_initpid_store();
+ store_unlock();
+ return answer;
}
-bool cgfs_chmod_file(const char *controller, const char *file, mode_t mode)
+static int wait_for_pid(pid_t pid)
{
- int cfd;
- size_t len;
- char *pathname;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
+ int status, ret;
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /file + \0
- */
- len = strlen(file) + 2;
- pathname = alloca(len);
- snprintf(pathname, len, "%s%s", dot_or_empty(file), file);
- if (fchmodat(cfd, pathname, mode, 0) < 0)
- return false;
- return true;
-}
+ if (pid <= 0)
+ return -1;
-static int chown_tasks_files(const char *dirname, uid_t uid, gid_t gid, int fd)
-{
- size_t len;
- char *fname;
-
- len = strlen(dirname) + strlen("/cgroup.procs") + 1;
- fname = alloca(len);
- snprintf(fname, len, "%s/tasks", dirname);
- if (fchownat(fd, fname, uid, gid, 0) != 0)
- return -errno;
- snprintf(fname, len, "%s/cgroup.procs", dirname);
- if (fchownat(fd, fname, uid, gid, 0) != 0)
- return -errno;
+again:
+ ret = waitpid(pid, &status, 0);
+ if (ret == -1) {
+ if (errno == EINTR)
+ goto again;
+ return -1;
+ }
+ if (ret != pid)
+ goto again;
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+ return -1;
return 0;
}
-int cgfs_chown_file(const char *controller, const char *file, uid_t uid, gid_t gid)
+char *get_pid_cgroup(pid_t pid, const char *contrl)
{
int cfd;
- size_t len;
- char *pathname;
- cfd = get_cgroup_fd(controller);
+ cfd = get_cgroup_fd(contrl);
if (cfd < 0)
return false;
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /file + \0
- */
- len = strlen(file) + 2;
- pathname = alloca(len);
- snprintf(pathname, len, "%s%s", dot_or_empty(file), file);
- if (fchownat(cfd, pathname, uid, gid, 0) < 0)
- return -errno;
-
- if (is_dir(pathname, cfd))
- // like cgmanager did, we want to chown the tasks file as well
- return chown_tasks_files(pathname, uid, gid, cfd);
+ if (pure_unified_layout(cgroup_ops))
+ return cg_unified_get_current_cgroup(pid);
- return 0;
+ return cg_legacy_get_current_cgroup(pid, contrl);
}
-FILE *open_pids_file(const char *controller, const char *cgroup)
+#define INITSCOPE "/init.scope"
+void prune_init_slice(char *cg)
{
- int fd, cfd;
- size_t len;
- char *pathname;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cgroup + / "cgroup.procs" + \0
- */
- len = strlen(cgroup) + strlen("cgroup.procs") + 3;
- pathname = alloca(len);
- snprintf(pathname, len, "%s%s/cgroup.procs", dot_or_empty(cgroup), cgroup);
+ char *point;
+ size_t cg_len = strlen(cg), initscope_len = strlen(INITSCOPE);
- fd = openat(cfd, pathname, O_WRONLY);
- if (fd < 0)
- return NULL;
+ if (cg_len < initscope_len)
+ return;
- return fdopen(fd, "w");
+ point = cg + cg_len - initscope_len;
+ if (strcmp(point, INITSCOPE) == 0) {
+ if (point == cg)
+ *(point+1) = '\0';
+ else
+ *point = '\0';
+ }
}
-static bool cgfs_iterate_cgroup(const char *controller, const char *cgroup, bool directories,
- void ***list, size_t typesize,
- void* (*iterator)(const char*, const char*, const char*))
+#define POLLIN_SET ( EPOLLIN | EPOLLHUP | EPOLLRDHUP )
+
+static bool wait_for_sock(int sock, int timeout)
{
- int cfd, fd, ret;
- size_t len;
- char *cg;
- char pathname[MAXPATHLEN];
- size_t sz = 0, asz = 0;
- struct dirent *dirent;
- DIR *dir;
+ struct epoll_event ev;
+ int epfd, ret, now, starttime, deltatime, saved_errno;
- cfd = get_cgroup_fd(controller);
- *list = NULL;
- if (cfd < 0)
+ if ((starttime = time(NULL)) < 0)
return false;
- /* Make sure we pass a relative path to *at() family of functions. */
- len = strlen(cgroup) + 1 /* . */ + 1 /* \0 */;
- cg = alloca(len);
- ret = snprintf(cg, len, "%s%s", dot_or_empty(cgroup), cgroup);
- if (ret < 0 || (size_t)ret >= len) {
- lxcfs_error("Pathname too long under %s\n", cgroup);
+ if ((epfd = epoll_create(1)) < 0) {
+ lxcfs_error("%s\n", "Failed to create epoll socket: %m.");
return false;
}
- fd = openat(cfd, cg, O_DIRECTORY);
- if (fd < 0)
- return false;
-
- dir = fdopendir(fd);
- if (!dir)
- return false;
-
- while ((dirent = readdir(dir))) {
- struct stat mystat;
-
- if (!strcmp(dirent->d_name, ".") ||
- !strcmp(dirent->d_name, ".."))
- continue;
-
- ret = snprintf(pathname, MAXPATHLEN, "%s/%s", cg, dirent->d_name);
- if (ret < 0 || ret >= MAXPATHLEN) {
- lxcfs_error("Pathname too long under %s\n", cg);
- continue;
- }
-
- ret = fstatat(cfd, pathname, &mystat, AT_SYMLINK_NOFOLLOW);
- if (ret) {
- lxcfs_error("Failed to stat %s: %s\n", pathname, strerror(errno));
- continue;
- }
- if ((!directories && !S_ISREG(mystat.st_mode)) ||
- (directories && !S_ISDIR(mystat.st_mode)))
- continue;
-
- if (sz+2 >= asz) {
- void **tmp;
- asz += BATCH_SIZE;
- do {
- tmp = realloc(*list, asz * typesize);
- } while (!tmp);
- *list = tmp;
- }
- (*list)[sz] = (*iterator)(controller, cg, dirent->d_name);
- (*list)[sz+1] = NULL;
- sz++;
- }
- if (closedir(dir) < 0) {
- lxcfs_error("Failed closedir for %s: %s\n", cgroup, strerror(errno));
- return false;
- }
- return true;
-}
-
-static void *make_children_list_entry(const char *controller, const char *cgroup, const char *dir_entry)
-{
- char *dup;
- do {
- dup = strdup(dir_entry);
- } while (!dup);
- return dup;
-}
-
-bool cgfs_list_children(const char *controller, const char *cgroup, char ***list)
-{
- return cgfs_iterate_cgroup(controller, cgroup, true, (void***)list, sizeof(*list), &make_children_list_entry);
-}
-
-void free_key(struct cgfs_files *k)
-{
- if (!k)
- return;
- free_disarm(k->name);
- free_disarm(k);
-}
-
-void free_keys(struct cgfs_files **keys)
-{
- int i;
-
- if (!keys)
- return;
- for (i = 0; keys[i]; i++) {
- free_key(keys[i]);
- }
- free_disarm(keys);
-}
-
-bool cgfs_param_exist(const char *controller, const char *cgroup, const char *file)
-{
- int ret, cfd;
- size_t len;
- char *fnam;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cgroup + / + file + \0
- */
- len = strlen(cgroup) + strlen(file) + 3;
- fnam = alloca(len);
- ret = snprintf(fnam, len, "%s%s/%s", dot_or_empty(cgroup), cgroup, file);
- if (ret < 0 || (size_t)ret >= len)
- return false;
-
- return (faccessat(cfd, fnam, F_OK, 0) == 0);
-}
-
-struct cgfs_files *cgfs_get_key(const char *controller, const char *cgroup, const char *file)
-{
- int ret, cfd;
- size_t len;
- char *fnam;
- struct stat sb;
- struct cgfs_files *newkey;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
-
- if (file && *file == '/')
- file++;
-
- if (file && strchr(file, '/'))
- return NULL;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cgroup + / + file + \0
- */
- len = strlen(cgroup) + 3;
- if (file)
- len += strlen(file) + 1;
- fnam = alloca(len);
- snprintf(fnam, len, "%s%s%s%s", dot_or_empty(cgroup), cgroup,
- file ? "/" : "", file ? file : "");
-
- ret = fstatat(cfd, fnam, &sb, 0);
- if (ret < 0)
- return NULL;
-
- do {
- newkey = malloc(sizeof(struct cgfs_files));
- } while (!newkey);
- if (file)
- newkey->name = must_copy_string(file);
- else if (strrchr(cgroup, '/'))
- newkey->name = must_copy_string(strrchr(cgroup, '/'));
- else
- newkey->name = must_copy_string(cgroup);
- newkey->uid = sb.st_uid;
- newkey->gid = sb.st_gid;
- newkey->mode = sb.st_mode;
-
- return newkey;
-}
-
-static void *make_key_list_entry(const char *controller, const char *cgroup, const char *dir_entry)
-{
- struct cgfs_files *entry = cgfs_get_key(controller, cgroup, dir_entry);
- if (!entry) {
- lxcfs_error("Error getting files under %s:%s\n", controller,
- cgroup);
- }
- return entry;
-}
-
-bool cgfs_list_keys(const char *controller, const char *cgroup, struct cgfs_files ***keys)
-{
- return cgfs_iterate_cgroup(controller, cgroup, false, (void***)keys, sizeof(*keys), &make_key_list_entry);
-}
-
-bool is_child_cgroup(const char *controller, const char *cgroup, const char *f)
-{
- int cfd;
- size_t len;
- char *fnam;
- int ret;
- struct stat sb;
-
- cfd = get_cgroup_fd(controller);
- if (cfd < 0)
- return false;
-
- /* Make sure we pass a relative path to *at() family of functions.
- * . + /cgroup + / + f + \0
- */
- len = strlen(cgroup) + strlen(f) + 3;
- fnam = alloca(len);
- ret = snprintf(fnam, len, "%s%s/%s", dot_or_empty(cgroup), cgroup, f);
- if (ret < 0 || (size_t)ret >= len)
- return false;
-
- ret = fstatat(cfd, fnam, &sb, 0);
- if (ret < 0 || !S_ISDIR(sb.st_mode))
- return false;
-
- return true;
-}
-
-#define SEND_CREDS_OK 0
-#define SEND_CREDS_NOTSK 1
-#define SEND_CREDS_FAIL 2
-static bool recv_creds(int sock, struct ucred *cred, char *v);
-static int wait_for_pid(pid_t pid);
-static int send_creds(int sock, struct ucred *cred, char v, bool pingfirst);
-static int send_creds_clone_wrapper(void *arg);
-
-/*
- * clone a task which switches to @task's namespace and writes '1'.
- * over a unix sock so we can read the task's reaper's pid in our
- * namespace
- *
- * Note: glibc's fork() does not respect pidns, which can lead to failed
- * assertions inside glibc (and thus failed forks) if the child's pid in
- * the pidns and the parent pid outside are identical. Using clone prevents
- * this issue.
- */
-static void write_task_init_pid_exit(int sock, pid_t target)
-{
- char fnam[100];
- pid_t pid;
- int fd, ret;
- size_t stack_size = sysconf(_SC_PAGESIZE);
- void *stack = alloca(stack_size);
-
- ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", (int)target);
- if (ret < 0 || ret >= sizeof(fnam))
- _exit(1);
-
- fd = open(fnam, O_RDONLY);
- if (fd < 0) {
- perror("write_task_init_pid_exit open of ns/pid");
- _exit(1);
- }
- if (setns(fd, 0)) {
- perror("write_task_init_pid_exit setns 1");
- close(fd);
- _exit(1);
- }
- pid = clone(send_creds_clone_wrapper, stack + stack_size, SIGCHLD, &sock);
- if (pid < 0)
- _exit(1);
- if (pid != 0) {
- if (!wait_for_pid(pid))
- _exit(1);
- _exit(0);
- }
-}
-
-static int send_creds_clone_wrapper(void *arg) {
- struct ucred cred;
- char v;
- int sock = *(int *)arg;
-
- /* we are the child */
- cred.uid = 0;
- cred.gid = 0;
- cred.pid = 1;
- v = '1';
- if (send_creds(sock, &cred, v, true) != SEND_CREDS_OK)
- return 1;
- return 0;
-}
-
-static pid_t get_init_pid_for_task(pid_t task)
-{
- int sock[2];
- pid_t pid;
- pid_t ret = -1;
- char v = '0';
- struct ucred cred;
-
- if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
- perror("socketpair");
- return -1;
- }
-
- pid = fork();
- if (pid < 0)
- goto out;
- if (!pid) {
- close(sock[1]);
- write_task_init_pid_exit(sock[0], task);
- _exit(0);
- }
-
- if (!recv_creds(sock[1], &cred, &v))
- goto out;
- ret = cred.pid;
-
-out:
- close(sock[0]);
- close(sock[1]);
- if (pid > 0)
- wait_for_pid(pid);
- return ret;
-}
-
-pid_t lookup_initpid_in_store(pid_t qpid)
-{
- pid_t answer = 0;
- struct stat sb;
- struct pidns_init_store *e;
- char fnam[100];
-
- snprintf(fnam, 100, "/proc/%d/ns/pid", qpid);
- store_lock();
- if (stat(fnam, &sb) < 0)
- goto out;
- e = lookup_verify_initpid(&sb);
- if (e) {
- answer = e->initpid;
- goto out;
- }
- answer = get_init_pid_for_task(qpid);
- if (answer > 0)
- save_initpid(&sb, answer);
-
-out:
- /* we prune at end in case we are returning
- * the value we were about to return */
- prune_initpid_store();
- store_unlock();
- return answer;
-}
-
-static int wait_for_pid(pid_t pid)
-{
- int status, ret;
-
- if (pid <= 0)
- return -1;
-
-again:
- ret = waitpid(pid, &status, 0);
- if (ret == -1) {
- if (errno == EINTR)
- goto again;
- return -1;
- }
- if (ret != pid)
- goto again;
- if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
- return -1;
- return 0;
-}
-
-
-/*
- * append pid to *src.
- * src: a pointer to a char* in which ot append the pid.
- * sz: the number of characters printed so far, minus trailing \0.
- * asz: the allocated size so far
- * pid: the pid to append
- */
-static void must_strcat_pid(char **src, size_t *sz, size_t *asz, pid_t pid)
-{
- must_strcat(src, sz, asz, "%d\n", (int)pid);
-}
-
-/*
- * Given a open file * to /proc/pid/{u,g}id_map, and an id
- * valid in the caller's namespace, return the id mapped into
- * pid's namespace.
- * Returns the mapped id, or -1 on error.
- */
-unsigned int
-convert_id_to_ns(FILE *idfile, unsigned int in_id)
-{
- unsigned int nsuid, // base id for a range in the idfile's namespace
- hostuid, // base id for a range in the caller's namespace
- count; // number of ids in this range
- char line[400];
- int ret;
-
- fseek(idfile, 0L, SEEK_SET);
- while (fgets(line, 400, idfile)) {
- ret = sscanf(line, "%u %u %u\n", &nsuid, &hostuid, &count);
- if (ret != 3)
- continue;
- if (hostuid + count < hostuid || nsuid + count < nsuid) {
- /*
- * uids wrapped around - unexpected as this is a procfile,
- * so just bail.
- */
- lxcfs_error("pid wrapparound at entry %u %u %u in %s\n",
- nsuid, hostuid, count, line);
- return -1;
- }
- if (hostuid <= in_id && hostuid+count > in_id) {
- /*
- * now since hostuid <= in_id < hostuid+count, and
- * hostuid+count and nsuid+count do not wrap around,
- * we know that nsuid+(in_id-hostuid) which must be
- * less that nsuid+(count) must not wrap around
- */
- return (in_id - hostuid) + nsuid;
- }
- }
-
- // no answer found
- return -1;
-}
-
-/*
- * for is_privileged_over,
- * specify whether we require the calling uid to be root in his
- * namespace
- */
-#define NS_ROOT_REQD true
-#define NS_ROOT_OPT false
-
-#define PROCLEN 100
-
-static bool is_privileged_over(pid_t pid, uid_t uid, uid_t victim, bool req_ns_root)
-{
- char fpath[PROCLEN];
- int ret;
- bool answer = false;
- uid_t nsuid;
-
- if (victim == -1 || uid == -1)
- return false;
-
- /*
- * If the request is one not requiring root in the namespace,
- * then having the same uid suffices. (i.e. uid 1000 has write
- * access to files owned by uid 1000
- */
- if (!req_ns_root && uid == victim)
- return true;
-
- ret = snprintf(fpath, PROCLEN, "/proc/%d/uid_map", pid);
- if (ret < 0 || ret >= PROCLEN)
- return false;
- FILE *f = fopen(fpath, "r");
- if (!f)
- return false;
-
- /* if caller's not root in his namespace, reject */
- nsuid = convert_id_to_ns(f, uid);
- if (nsuid)
- goto out;
-
- /*
- * If victim is not mapped into caller's ns, reject.
- * XXX I'm not sure this check is needed given that fuse
- * will be sending requests where the vfs has converted
- */
- nsuid = convert_id_to_ns(f, victim);
- if (nsuid == -1)
- goto out;
-
- answer = true;
-
-out:
- fclose(f);
- return answer;
-}
-
-static bool perms_include(int fmode, mode_t req_mode)
-{
- mode_t r;
-
- switch (req_mode & O_ACCMODE) {
- case O_RDONLY:
- r = S_IROTH;
- break;
- case O_WRONLY:
- r = S_IWOTH;
- break;
- case O_RDWR:
- r = S_IROTH | S_IWOTH;
- break;
- default:
- return false;
- }
- return ((fmode & r) == r);
-}
-
-
-/*
- * taskcg is a/b/c
- * querycg is /a/b/c/d/e
- * we return 'd'
- */
-static char *get_next_cgroup_dir(const char *taskcg, const char *querycg)
-{
- char *start, *end;
-
- if (strlen(taskcg) <= strlen(querycg)) {
- lxcfs_error("%s\n", "I was fed bad input.");
- return NULL;
- }
-
- if ((strcmp(querycg, "/") == 0) || (strcmp(querycg, "./") == 0))
- start = strdup(taskcg + 1);
- else
- start = strdup(taskcg + strlen(querycg) + 1);
- if (!start)
- return NULL;
- end = strchr(start, '/');
- if (end)
- *end = '\0';
- return start;
-}
-
-char *get_pid_cgroup(pid_t pid, const char *contrl)
-{
- int cfd;
-
- cfd = get_cgroup_fd(contrl);
- if (cfd < 0)
- return false;
-
- if (pure_unified_layout(cgroup_ops))
- return cg_unified_get_current_cgroup(pid);
-
- return cg_legacy_get_current_cgroup(pid, contrl);
-}
-
-/*
- * check whether a fuse context may access a cgroup dir or file
- *
- * If file is not null, it is a cgroup file to check under cg.
- * If file is null, then we are checking perms on cg itself.
- *
- * For files we can check the mode of the list_keys result.
- * For cgroups, we must make assumptions based on the files under the
- * cgroup, because cgmanager doesn't tell us ownership/perms of cgroups
- * yet.
- */
-static bool fc_may_access(struct fuse_context *fc, const char *contrl, const char *cg, const char *file, mode_t mode)
-{
- struct cgfs_files *k = NULL;
- bool ret = false;
-
- k = cgfs_get_key(contrl, cg, file);
- if (!k)
- return false;
-
- if (is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_OPT)) {
- if (perms_include(k->mode >> 6, mode)) {
- ret = true;
- goto out;
- }
- }
- if (fc->gid == k->gid) {
- if (perms_include(k->mode >> 3, mode)) {
- ret = true;
- goto out;
- }
- }
- ret = perms_include(k->mode, mode);
-
-out:
- free_key(k);
- return ret;
-}
-
-#define INITSCOPE "/init.scope"
-void prune_init_slice(char *cg)
-{
- char *point;
- size_t cg_len = strlen(cg), initscope_len = strlen(INITSCOPE);
-
- if (cg_len < initscope_len)
- return;
-
- point = cg + cg_len - initscope_len;
- if (strcmp(point, INITSCOPE) == 0) {
- if (point == cg)
- *(point+1) = '\0';
- else
- *point = '\0';
- }
-}
-
-/*
- * If pid is in /a/b/c/d, he may only act on things under cg=/a/b/c/d.
- * If pid is in /a, he may act on /a/b, but not on /b.
- * if the answer is false and nextcg is not NULL, then *nextcg will point
- * to a string containing the next cgroup directory under cg, which must be
- * freed by the caller.
- */
-static bool caller_is_in_ancestor(pid_t pid, const char *contrl, const char *cg, char **nextcg)
-{
- bool answer = false;
- char *c2 = get_pid_cgroup(pid, contrl);
- char *linecmp;
-
- if (!c2)
- return false;
- prune_init_slice(c2);
-
- /*
- * callers pass in '/' or './' (openat()) for root cgroup, otherwise
- * they pass in a cgroup without leading '/'
- *
- * The original line here was:
- * linecmp = *cg == '/' ? c2 : c2+1;
- * TODO: I'm not sure why you'd want to increment when *cg != '/'?
- * Serge, do you know?
- */
- if (*cg == '/' || !strncmp(cg, "./", 2))
- linecmp = c2;
- else
- linecmp = c2 + 1;
- if (strncmp(linecmp, cg, strlen(linecmp)) != 0) {
- if (nextcg) {
- *nextcg = get_next_cgroup_dir(linecmp, cg);
- }
- goto out;
- }
- answer = true;
-
-out:
- free(c2);
- return answer;
-}
-
-/*
- * If pid is in /a/b/c, he may see that /a exists, but not /b or /a/c.
- */
-static bool caller_may_see_dir(pid_t pid, const char *contrl, const char *cg)
-{
- bool answer = false;
- char *c2, *task_cg;
- size_t target_len, task_len;
-
- if (strcmp(cg, "/") == 0 || strcmp(cg, "./") == 0)
- return true;
-
- c2 = get_pid_cgroup(pid, contrl);
- if (!c2)
- return false;
- prune_init_slice(c2);
-
- task_cg = c2 + 1;
- target_len = strlen(cg);
- task_len = strlen(task_cg);
- if (task_len == 0) {
- /* Task is in the root cg, it can see everything. This case is
- * not handled by the strmcps below, since they test for the
- * last /, but that is the first / that we've chopped off
- * above.
- */
- answer = true;
- goto out;
- }
- if (strcmp(cg, task_cg) == 0) {
- answer = true;
- goto out;
- }
- if (target_len < task_len) {
- /* looking up a parent dir */
- if (strncmp(task_cg, cg, target_len) == 0 && task_cg[target_len] == '/')
- answer = true;
- goto out;
- }
- if (target_len > task_len) {
- /* looking up a child dir */
- if (strncmp(task_cg, cg, task_len) == 0 && cg[task_len] == '/')
- answer = true;
- goto out;
- }
-
-out:
- free(c2);
- return answer;
-}
-
-/*
- * given /cgroup/freezer/a/b, return "freezer".
- * the returned char* should NOT be freed.
- */
-static char *pick_controller_from_path(struct fuse_context *fc, const char *path)
-{
- const char *p1;
- char *contr, *slash;
-
- if (strlen(path) < 9) {
- errno = EACCES;
- return NULL;
- }
- if (*(path + 7) != '/') {
- errno = EINVAL;
- return NULL;
- }
- p1 = path + 8;
- contr = strdupa(p1);
- if (!contr) {
- errno = ENOMEM;
- return NULL;
- }
- slash = strstr(contr, "/");
- if (slash)
- *slash = '\0';
-
- for (struct hierarchy **h = cgroup_ops->hierarchies; h && *h; h++) {
- if ((*h)->__controllers && strcmp((*h)->__controllers, contr) == 0)
- return (*h)->__controllers;
- }
- errno = ENOENT;
- return NULL;
-}
-
-/*
- * Find the start of cgroup in /cgroup/controller/the/cgroup/path
- * Note that the returned value may include files (keynames) etc
- */
-static const char *find_cgroup_in_path(const char *path)
-{
- const char *p1;
-
- if (strlen(path) < 9) {
- errno = EACCES;
- return NULL;
- }
- p1 = strstr(path + 8, "/");
- if (!p1) {
- errno = EINVAL;
- return NULL;
- }
- errno = 0;
- return p1 + 1;
-}
-
-/*
- * split the last path element from the path in @cg.
- * @dir is newly allocated and should be freed, @last not
-*/
-static void get_cgdir_and_path(const char *cg, char **dir, char **last)
-{
- char *p;
-
- do {
- *dir = strdup(cg);
- } while (!*dir);
- *last = strrchr(cg, '/');
- if (!*last) {
- *last = NULL;
- return;
- }
- p = strrchr(*dir, '/');
- *p = '\0';
-}
-
-/*
- * FUSE ops for /cgroup
- */
-
-int cg_getattr(const char *path, struct stat *sb)
-{
- struct timespec now;
- struct fuse_context *fc = fuse_get_context();
- char * cgdir = NULL;
- char *last = NULL, *path1, *path2;
- struct cgfs_files *k = NULL;
- const char *cgroup;
- const char *controller = NULL;
- int ret = -ENOENT;
-
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- memset(sb, 0, sizeof(struct stat));
-
- if (clock_gettime(CLOCK_REALTIME, &now) < 0)
- return -EINVAL;
-
- sb->st_uid = sb->st_gid = 0;
- sb->st_atim = sb->st_mtim = sb->st_ctim = now;
- sb->st_size = 0;
-
- if (strcmp(path, "/cgroup") == 0) {
- sb->st_mode = S_IFDIR | 00755;
- sb->st_nlink = 2;
- return 0;
- }
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -errno;
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) {
- /* this is just /cgroup/controller, return it as a dir */
- sb->st_mode = S_IFDIR | 00755;
- sb->st_nlink = 2;
- return 0;
- }
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
-
- if (!last) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = last;
- }
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- /* check that cgcopy is either a child cgroup of cgdir, or listed in its keys.
- * Then check that caller's cgroup is under path if last is a child
- * cgroup, or cgdir if last is a file */
-
- if (is_child_cgroup(controller, path1, path2)) {
- if (!caller_may_see_dir(initpid, controller, cgroup)) {
- ret = -ENOENT;
- goto out;
- }
- if (!caller_is_in_ancestor(initpid, controller, cgroup, NULL)) {
- /* this is just /cgroup/controller, return it as a dir */
- sb->st_mode = S_IFDIR | 00555;
- sb->st_nlink = 2;
- ret = 0;
- goto out;
- }
- if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY)) {
- ret = -EACCES;
- goto out;
- }
-
- // get uid, gid, from '/tasks' file and make up a mode
- // That is a hack, until cgmanager gains a GetCgroupPerms fn.
- sb->st_mode = S_IFDIR | 00755;
- k = cgfs_get_key(controller, cgroup, NULL);
- if (!k) {
- sb->st_uid = sb->st_gid = 0;
- } else {
- sb->st_uid = k->uid;
- sb->st_gid = k->gid;
- }
- free_key(k);
- sb->st_nlink = 2;
- ret = 0;
- goto out;
- }
-
- if ((k = cgfs_get_key(controller, path1, path2)) != NULL) {
- sb->st_mode = S_IFREG | k->mode;
- sb->st_nlink = 1;
- sb->st_uid = k->uid;
- sb->st_gid = k->gid;
- sb->st_size = 0;
- free_key(k);
- if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
- ret = -ENOENT;
- goto out;
- }
- ret = 0;
- }
-
-out:
- free(cgdir);
- return ret;
-}
-
-int cg_opendir(const char *path, struct fuse_file_info *fi)
-{
- struct fuse_context *fc = fuse_get_context();
- const char *cgroup;
- struct file_info *dir_info;
- char *controller = NULL;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (strcmp(path, "/cgroup") == 0) {
- cgroup = NULL;
- controller = NULL;
- } else {
- // return list of keys for the controller, and list of child cgroups
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -errno;
-
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) {
- /* this is just /cgroup/controller, return its contents */
- cgroup = "/";
- }
- }
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (cgroup) {
- if (!caller_may_see_dir(initpid, controller, cgroup))
- return -ENOENT;
- if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY))
- return -EACCES;
- }
-
- /* we'll free this at cg_releasedir */
- dir_info = malloc(sizeof(*dir_info));
- if (!dir_info)
- return -ENOMEM;
- dir_info->controller = must_copy_string(controller);
- dir_info->cgroup = must_copy_string(cgroup);
- dir_info->type = LXC_TYPE_CGDIR;
- dir_info->buf = NULL;
- dir_info->file = NULL;
- dir_info->buflen = 0;
-
- fi->fh = (unsigned long)dir_info;
- return 0;
-}
-
-int cg_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
- struct fuse_file_info *fi)
-{
- struct file_info *d = (struct file_info *)fi->fh;
- struct cgfs_files **list = NULL;
- int i, ret;
- char *nextcg = NULL;
- struct fuse_context *fc = fuse_get_context();
- char **clist = NULL;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (filler(buf, ".", NULL, 0) != 0 || filler(buf, "..", NULL, 0) != 0)
- return -EIO;
-
- if (d->type != LXC_TYPE_CGDIR) {
- lxcfs_error("%s\n", "Internal error: file cache info used in readdir.");
- return -EIO;
- }
- if (!d->cgroup && !d->controller) {
- /*
- * ls /var/lib/lxcfs/cgroup - just show list of controllers.
- * This only works with the legacy hierarchy.
- */
- for (struct hierarchy **h = cgroup_ops->hierarchies; h && *h; h++) {
- if (is_unified_hierarchy(*h))
- continue;
-
- if ((*h)->__controllers && filler(buf, (*h)->__controllers, NULL, 0))
- return -EIO;
- }
-
- return 0;
- }
-
- if (!cgfs_list_keys(d->controller, d->cgroup, &list)) {
- // not a valid cgroup
- ret = -EINVAL;
- goto out;
- }
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (!caller_is_in_ancestor(initpid, d->controller, d->cgroup, &nextcg)) {
- if (nextcg) {
- ret = filler(buf, nextcg, NULL, 0);
- free(nextcg);
- if (ret != 0) {
- ret = -EIO;
- goto out;
- }
- }
- ret = 0;
- goto out;
- }
-
- for (i = 0; list && list[i]; i++) {
- if (filler(buf, list[i]->name, NULL, 0) != 0) {
- ret = -EIO;
- goto out;
- }
- }
-
- // now get the list of child cgroups
-
- if (!cgfs_list_children(d->controller, d->cgroup, &clist)) {
- ret = 0;
- goto out;
- }
- if (clist) {
- for (i = 0; clist[i]; i++) {
- if (filler(buf, clist[i], NULL, 0) != 0) {
- ret = -EIO;
- goto out;
- }
- }
- }
- ret = 0;
-
-out:
- free_keys(list);
- if (clist) {
- for (i = 0; clist[i]; i++)
- free(clist[i]);
- free(clist);
- }
- return ret;
-}
-
-void do_release_file_info(struct fuse_file_info *fi)
-{
- struct file_info *f = (struct file_info *)fi->fh;
-
- if (!f)
- return;
-
- fi->fh = 0;
-
- free_disarm(f->controller);
- free_disarm(f->cgroup);
- free_disarm(f->file);
- free_disarm(f->buf);
- free_disarm(f);
-}
-
-int cg_releasedir(const char *path, struct fuse_file_info *fi)
-{
- do_release_file_info(fi);
- return 0;
-}
-
-int cg_open(const char *path, struct fuse_file_info *fi)
-{
- const char *cgroup;
- char *last = NULL, *path1, *path2, * cgdir = NULL, *controller;
- struct cgfs_files *k = NULL;
- struct file_info *file_info;
- struct fuse_context *fc = fuse_get_context();
- int ret;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -errno;
- cgroup = find_cgroup_in_path(path);
- if (!cgroup)
- return -errno;
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!last) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = last;
- }
-
- k = cgfs_get_key(controller, path1, path2);
- if (!k) {
- ret = -EINVAL;
- goto out;
- }
- free_key(k);
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (!caller_may_see_dir(initpid, controller, path1)) {
- ret = -ENOENT;
- goto out;
- }
- if (!fc_may_access(fc, controller, path1, path2, fi->flags)) {
- ret = -EACCES;
- goto out;
- }
-
- /* we'll free this at cg_release */
- file_info = malloc(sizeof(*file_info));
- if (!file_info) {
- ret = -ENOMEM;
- goto out;
- }
- file_info->controller = must_copy_string(controller);
- file_info->cgroup = must_copy_string(path1);
- file_info->file = must_copy_string(path2);
- file_info->type = LXC_TYPE_CGFILE;
- file_info->buf = NULL;
- file_info->buflen = 0;
-
- fi->fh = (unsigned long)file_info;
- ret = 0;
-
-out:
- free(cgdir);
- return ret;
-}
-
-int cg_access(const char *path, int mode)
-{
- int ret;
- const char *cgroup;
- char *path1, *path2, *controller;
- char *last = NULL, *cgdir = NULL;
- struct cgfs_files *k = NULL;
- struct fuse_context *fc = fuse_get_context();
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (strcmp(path, "/cgroup") == 0)
- return 0;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -errno;
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) {
- // access("/sys/fs/cgroup/systemd", mode) - rx allowed, w not
- if ((mode & W_OK) == 0)
- return 0;
- return -EACCES;
- }
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!last) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = last;
- }
-
- k = cgfs_get_key(controller, path1, path2);
- if (!k) {
- if ((mode & W_OK) == 0)
- ret = 0;
- else
- ret = -EACCES;
- goto out;
- }
- free_key(k);
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (!caller_may_see_dir(initpid, controller, path1)) {
- ret = -ENOENT;
- goto out;
- }
- if (!fc_may_access(fc, controller, path1, path2, mode)) {
- ret = -EACCES;
- goto out;
- }
-
- ret = 0;
-
-out:
- free(cgdir);
- return ret;
-}
-
-int cg_release(const char *path, struct fuse_file_info *fi)
-{
- do_release_file_info(fi);
- return 0;
-}
-
-#define POLLIN_SET ( EPOLLIN | EPOLLHUP | EPOLLRDHUP )
-
-static bool wait_for_sock(int sock, int timeout)
-{
- struct epoll_event ev;
- int epfd, ret, now, starttime, deltatime, saved_errno;
-
- if ((starttime = time(NULL)) < 0)
- return false;
-
- if ((epfd = epoll_create(1)) < 0) {
- lxcfs_error("%s\n", "Failed to create epoll socket: %m.");
- return false;
- }
-
- ev.events = POLLIN_SET;
- ev.data.fd = sock;
- if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
- lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
- close(epfd);
- return false;
- }
-
-again:
- if ((now = time(NULL)) < 0) {
- close(epfd);
- return false;
- }
-
- deltatime = (starttime + timeout) - now;
- if (deltatime < 0) { // timeout
- errno = 0;
- close(epfd);
- return false;
- }
- ret = epoll_wait(epfd, &ev, 1, 1000*deltatime + 1);
- if (ret < 0 && errno == EINTR)
- goto again;
- saved_errno = errno;
- close(epfd);
-
- if (ret <= 0) {
- errno = saved_errno;
- return false;
- }
- return true;
-}
-
-static int msgrecv(int sockfd, void *buf, size_t len)
-{
- if (!wait_for_sock(sockfd, 2))
- return -1;
- return recv(sockfd, buf, len, MSG_DONTWAIT);
-}
-
-static int send_creds(int sock, struct ucred *cred, char v, bool pingfirst)
-{
- struct msghdr msg = { 0 };
- struct iovec iov;
- struct cmsghdr *cmsg;
- char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
- char buf[1];
- buf[0] = 'p';
-
- if (pingfirst) {
- if (msgrecv(sock, buf, 1) != 1) {
- lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
- return SEND_CREDS_FAIL;
- }
- }
-
- msg.msg_control = cmsgbuf;
- msg.msg_controllen = sizeof(cmsgbuf);
-
- cmsg = CMSG_FIRSTHDR(&msg);
- cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
- cmsg->cmsg_level = SOL_SOCKET;
- cmsg->cmsg_type = SCM_CREDENTIALS;
- memcpy(CMSG_DATA(cmsg), cred, sizeof(*cred));
-
- msg.msg_name = NULL;
- msg.msg_namelen = 0;
-
- buf[0] = v;
- iov.iov_base = buf;
- iov.iov_len = sizeof(buf);
- msg.msg_iov = &iov;
- msg.msg_iovlen = 1;
-
- if (sendmsg(sock, &msg, 0) < 0) {
- lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
- if (errno == 3)
- return SEND_CREDS_NOTSK;
- return SEND_CREDS_FAIL;
- }
-
- return SEND_CREDS_OK;
-}
-
-static bool recv_creds(int sock, struct ucred *cred, char *v)
-{
- struct msghdr msg = { 0 };
- struct iovec iov;
- struct cmsghdr *cmsg;
- char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
- char buf[1];
- int ret;
- int optval = 1;
-
- *v = '1';
-
- cred->pid = -1;
- cred->uid = -1;
- cred->gid = -1;
-
- if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
- lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
- return false;
- }
- buf[0] = '1';
- if (write(sock, buf, 1) != 1) {
- lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
- return false;
- }
-
- msg.msg_name = NULL;
- msg.msg_namelen = 0;
- msg.msg_control = cmsgbuf;
- msg.msg_controllen = sizeof(cmsgbuf);
-
- iov.iov_base = buf;
- iov.iov_len = sizeof(buf);
- msg.msg_iov = &iov;
- msg.msg_iovlen = 1;
-
- if (!wait_for_sock(sock, 2)) {
- lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
- return false;
- }
- ret = recvmsg(sock, &msg, MSG_DONTWAIT);
- if (ret < 0) {
- lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
- return false;
- }
-
- cmsg = CMSG_FIRSTHDR(&msg);
-
- if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)) &&
- cmsg->cmsg_level == SOL_SOCKET &&
- cmsg->cmsg_type == SCM_CREDENTIALS) {
- memcpy(cred, CMSG_DATA(cmsg), sizeof(*cred));
- }
- *v = buf[0];
-
- return true;
-}
-
-struct pid_ns_clone_args {
- int *cpipe;
- int sock;
- pid_t tpid;
- int (*wrapped) (int, pid_t); // pid_from_ns or pid_to_ns
-};
-
-/*
- * pid_ns_clone_wrapper - wraps pid_to_ns or pid_from_ns for usage
- * with clone(). This simply writes '1' as ACK back to the parent
- * before calling the actual wrapped function.
- */
-static int pid_ns_clone_wrapper(void *arg) {
- struct pid_ns_clone_args* args = (struct pid_ns_clone_args *) arg;
- char b = '1';
-
- close(args->cpipe[0]);
- if (write(args->cpipe[1], &b, sizeof(char)) < 0)
- lxcfs_error("(child): error on write: %s.\n", strerror(errno));
- close(args->cpipe[1]);
- return args->wrapped(args->sock, args->tpid);
-}
-
-/*
- * pid_to_ns - reads pids from a ucred over a socket, then writes the
- * int value back over the socket. This shifts the pid from the
- * sender's pidns into tpid's pidns.
- */
-static int pid_to_ns(int sock, pid_t tpid)
-{
- char v = '0';
- struct ucred cred;
-
- while (recv_creds(sock, &cred, &v)) {
- if (v == '1')
- return 0;
- if (write(sock, &cred.pid, sizeof(pid_t)) != sizeof(pid_t))
- return 1;
- }
- return 0;
-}
-
-
-/*
- * pid_to_ns_wrapper: when you setns into a pidns, you yourself remain
- * in your old pidns. Only children which you clone will be in the target
- * pidns. So the pid_to_ns_wrapper does the setns, then clones a child to
- * actually convert pids.
- *
- * Note: glibc's fork() does not respect pidns, which can lead to failed
- * assertions inside glibc (and thus failed forks) if the child's pid in
- * the pidns and the parent pid outside are identical. Using clone prevents
- * this issue.
- */
-static void pid_to_ns_wrapper(int sock, pid_t tpid)
-{
- int newnsfd = -1, ret, cpipe[2];
- char fnam[100];
- pid_t cpid;
- char v;
-
- ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
- if (ret < 0 || ret >= sizeof(fnam))
- _exit(1);
- newnsfd = open(fnam, O_RDONLY);
- if (newnsfd < 0)
- _exit(1);
- if (setns(newnsfd, 0) < 0)
- _exit(1);
- close(newnsfd);
-
- if (pipe(cpipe) < 0)
- _exit(1);
-
- struct pid_ns_clone_args args = {
- .cpipe = cpipe,
- .sock = sock,
- .tpid = tpid,
- .wrapped = &pid_to_ns
- };
- size_t stack_size = sysconf(_SC_PAGESIZE);
- void *stack = alloca(stack_size);
-
- cpid = clone(pid_ns_clone_wrapper, stack + stack_size, SIGCHLD, &args);
- if (cpid < 0)
- _exit(1);
-
- // give the child 1 second to be done forking and
- // write its ack
- if (!wait_for_sock(cpipe[0], 1))
- _exit(1);
- ret = read(cpipe[0], &v, 1);
- if (ret != sizeof(char) || v != '1')
- _exit(1);
-
- if (!wait_for_pid(cpid))
- _exit(1);
- _exit(0);
-}
-
-/*
- * To read cgroup files with a particular pid, we will setns into the child
- * pidns, open a pipe, fork a child - which will be the first to really be in
- * the child ns - which does the cgfs_get_value and writes the data to the pipe.
- */
-bool do_read_pids(pid_t tpid, const char *contrl, const char *cg, const char *file, char **d)
-{
- int sock[2] = {-1, -1};
- char *tmpdata = NULL;
- int ret;
- pid_t qpid, cpid = -1;
- bool answer = false;
- char v = '0';
- struct ucred cred;
- size_t sz = 0, asz = 0;
-
- if (!cgroup_ops->get(cgroup_ops, contrl, cg, file, &tmpdata))
- return false;
-
- /*
- * Now we read the pids from returned data one by one, pass
- * them into a child in the target namespace, read back the
- * translated pids, and put them into our to-return data
- */
-
- if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
- perror("socketpair");
- free(tmpdata);
- return false;
- }
-
- cpid = fork();
- if (cpid == -1)
- goto out;
-
- if (!cpid) // child - exits when done
- pid_to_ns_wrapper(sock[1], tpid);
-
- char *ptr = tmpdata;
- cred.uid = 0;
- cred.gid = 0;
- while (sscanf(ptr, "%d\n", &qpid) == 1) {
- cred.pid = qpid;
- ret = send_creds(sock[0], &cred, v, true);
-
- if (ret == SEND_CREDS_NOTSK)
- goto next;
- if (ret == SEND_CREDS_FAIL)
- goto out;
-
- // read converted results
- if (!wait_for_sock(sock[0], 2)) {
- lxcfs_error("Timed out waiting for pid from child: %s.\n", strerror(errno));
- goto out;
- }
- if (read(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
- lxcfs_error("Error reading pid from child: %s.\n", strerror(errno));
- goto out;
- }
- must_strcat_pid(d, &sz, &asz, qpid);
-next:
- ptr = strchr(ptr, '\n');
- if (!ptr)
- break;
- ptr++;
- }
-
- cred.pid = getpid();
- v = '1';
- if (send_creds(sock[0], &cred, v, true) != SEND_CREDS_OK) {
- // failed to ask child to exit
- lxcfs_error("Failed to ask child to exit: %s.\n", strerror(errno));
- goto out;
- }
-
- answer = true;
-
-out:
- free(tmpdata);
- if (cpid != -1)
- wait_for_pid(cpid);
- if (sock[0] != -1) {
- close(sock[0]);
- close(sock[1]);
- }
- return answer;
-}
-
-int cg_read(const char *path, char *buf, size_t size, off_t offset,
- struct fuse_file_info *fi)
-{
- struct fuse_context *fc = fuse_get_context();
- struct file_info *f = (struct file_info *)fi->fh;
- struct cgfs_files *k = NULL;
- char *data = NULL;
- int ret, s;
- bool r;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (f->type != LXC_TYPE_CGFILE) {
- lxcfs_error("%s\n", "Internal error: directory cache info used in cg_read.");
- return -EIO;
- }
-
- if (offset)
- return 0;
-
- if (!f->controller)
- return -EINVAL;
-
- if ((k = cgfs_get_key(f->controller, f->cgroup, f->file)) == NULL) {
- return -EINVAL;
- }
- free_key(k);
-
-
- if (!fc_may_access(fc, f->controller, f->cgroup, f->file, O_RDONLY)) {
- ret = -EACCES;
- goto out;
- }
-
- if (strcmp(f->file, "tasks") == 0 ||
- strcmp(f->file, "/tasks") == 0 ||
- strcmp(f->file, "/cgroup.procs") == 0 ||
- strcmp(f->file, "cgroup.procs") == 0)
- // special case - we have to translate the pids
- r = do_read_pids(fc->pid, f->controller, f->cgroup, f->file, &data);
- else
- r = cgroup_ops->get(cgroup_ops, f->controller, f->cgroup, f->file, &data);
-
- if (!r) {
- ret = -EINVAL;
- goto out;
- }
-
- if (!data) {
- ret = 0;
- goto out;
- }
- s = strlen(data);
- if (s > size)
- s = size;
- memcpy(buf, data, s);
- if (s > 0 && s < size && data[s-1] != '\n')
- buf[s++] = '\n';
-
- ret = s;
-
-out:
- free(data);
- return ret;
-}
-
-static int pid_from_ns(int sock, pid_t tpid)
-{
- pid_t vpid;
- struct ucred cred;
- char v;
- int ret;
-
- cred.uid = 0;
- cred.gid = 0;
- while (1) {
- if (!wait_for_sock(sock, 2)) {
- lxcfs_error("%s\n", "Timeout reading from parent.");
- return 1;
- }
- if ((ret = read(sock, &vpid, sizeof(pid_t))) != sizeof(pid_t)) {
- lxcfs_error("Bad read from parent: %s.\n", strerror(errno));
- return 1;
- }
- if (vpid == -1) // done
- break;
- v = '0';
- cred.pid = vpid;
- if (send_creds(sock, &cred, v, true) != SEND_CREDS_OK) {
- v = '1';
- cred.pid = getpid();
- if (send_creds(sock, &cred, v, false) != SEND_CREDS_OK)
- return 1;
- }
- }
- return 0;
-}
-
-static void pid_from_ns_wrapper(int sock, pid_t tpid)
-{
- int newnsfd = -1, ret, cpipe[2];
- char fnam[100];
- pid_t cpid;
- char v;
-
- ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
- if (ret < 0 || ret >= sizeof(fnam))
- _exit(1);
- newnsfd = open(fnam, O_RDONLY);
- if (newnsfd < 0)
- _exit(1);
- if (setns(newnsfd, 0) < 0)
- _exit(1);
- close(newnsfd);
-
- if (pipe(cpipe) < 0)
- _exit(1);
-
- struct pid_ns_clone_args args = {
- .cpipe = cpipe,
- .sock = sock,
- .tpid = tpid,
- .wrapped = &pid_from_ns
- };
- size_t stack_size = sysconf(_SC_PAGESIZE);
- void *stack = alloca(stack_size);
-
- cpid = clone(pid_ns_clone_wrapper, stack + stack_size, SIGCHLD, &args);
- if (cpid < 0)
- _exit(1);
-
- // give the child 1 second to be done forking and
- // write its ack
- if (!wait_for_sock(cpipe[0], 1))
- _exit(1);
- ret = read(cpipe[0], &v, 1);
- if (ret != sizeof(char) || v != '1')
- _exit(1);
-
- if (!wait_for_pid(cpid))
- _exit(1);
- _exit(0);
-}
-
-/*
- * Given host @uid, return the uid to which it maps in
- * @pid's user namespace, or -1 if none.
- */
-bool hostuid_to_ns(uid_t uid, pid_t pid, uid_t *answer)
-{
- FILE *f;
- char line[400];
-
- sprintf(line, "/proc/%d/uid_map", pid);
- if ((f = fopen(line, "r")) == NULL) {
- return false;
- }
-
- *answer = convert_id_to_ns(f, uid);
- fclose(f);
-
- if (*answer == -1)
- return false;
- return true;
-}
-
-/*
- * get_pid_creds: get the real uid and gid of @pid from
- * /proc/$$/status
- * (XXX should we use euid here?)
- */
-void get_pid_creds(pid_t pid, uid_t *uid, gid_t *gid)
-{
- char line[400];
- uid_t u;
- gid_t g;
- FILE *f;
-
- *uid = -1;
- *gid = -1;
- sprintf(line, "/proc/%d/status", pid);
- if ((f = fopen(line, "r")) == NULL) {
- lxcfs_error("Error opening %s: %s\n", line, strerror(errno));
- return;
- }
- while (fgets(line, 400, f)) {
- if (strncmp(line, "Uid:", 4) == 0) {
- if (sscanf(line+4, "%u", &u) != 1) {
- lxcfs_error("bad uid line for pid %u\n", pid);
- fclose(f);
- return;
- }
- *uid = u;
- } else if (strncmp(line, "Gid:", 4) == 0) {
- if (sscanf(line+4, "%u", &g) != 1) {
- lxcfs_error("bad gid line for pid %u\n", pid);
- fclose(f);
- return;
- }
- *gid = g;
- }
- }
- fclose(f);
-}
-
-/*
- * May the requestor @r move victim @v to a new cgroup?
- * This is allowed if
- * . they are the same task
- * . they are ownedy by the same uid
- * . @r is root on the host, or
- * . @v's uid is mapped into @r's where @r is root.
- */
-bool may_move_pid(pid_t r, uid_t r_uid, pid_t v)
-{
- uid_t v_uid, tmpuid;
- gid_t v_gid;
-
- if (r == v)
- return true;
- if (r_uid == 0)
- return true;
- get_pid_creds(v, &v_uid, &v_gid);
- if (r_uid == v_uid)
- return true;
- if (hostuid_to_ns(r_uid, r, &tmpuid) && tmpuid == 0
- && hostuid_to_ns(v_uid, r, &tmpuid))
- return true;
- return false;
-}
-
-static bool do_write_pids(pid_t tpid, uid_t tuid, const char *contrl, const char *cg,
- const char *file, const char *buf)
-{
- int sock[2] = {-1, -1};
- pid_t qpid, cpid = -1;
- FILE *pids_file = NULL;
- bool answer = false, fail = false;
-
- pids_file = open_pids_file(contrl, cg);
- if (!pids_file)
+ ev.events = POLLIN_SET;
+ ev.data.fd = sock;
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
+ lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
+ close(epfd);
return false;
-
- /*
- * write the pids to a socket, have helper in writer's pidns
- * call movepid for us
- */
- if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
- perror("socketpair");
- goto out;
- }
-
- cpid = fork();
- if (cpid == -1)
- goto out;
-
- if (!cpid) { // child
- fclose(pids_file);
- pid_from_ns_wrapper(sock[1], tpid);
- }
-
- const char *ptr = buf;
- while (sscanf(ptr, "%d", &qpid) == 1) {
- struct ucred cred;
- char v;
-
- if (write(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
- lxcfs_error("Error writing pid to child: %s.\n", strerror(errno));
- goto out;
- }
-
- if (recv_creds(sock[0], &cred, &v)) {
- if (v == '0') {
- if (!may_move_pid(tpid, tuid, cred.pid)) {
- fail = true;
- break;
- }
- if (fprintf(pids_file, "%d", (int) cred.pid) < 0)
- fail = true;
- }
- }
-
- ptr = strchr(ptr, '\n');
- if (!ptr)
- break;
- ptr++;
- }
-
- /* All good, write the value */
- qpid = -1;
- if (write(sock[0], &qpid ,sizeof(qpid)) != sizeof(qpid))
- lxcfs_error("%s\n", "Warning: failed to ask child to exit.");
-
- if (!fail)
- answer = true;
-
-out:
- if (cpid != -1)
- wait_for_pid(cpid);
- if (sock[0] != -1) {
- close(sock[0]);
- close(sock[1]);
}
- if (pids_file) {
- if (fclose(pids_file) != 0)
- answer = false;
- }
- return answer;
-}
-
-int cg_write(const char *path, const char *buf, size_t size, off_t offset,
- struct fuse_file_info *fi)
-{
- struct fuse_context *fc = fuse_get_context();
- char *localbuf = NULL;
- struct cgfs_files *k = NULL;
- struct file_info *f = (struct file_info *)fi->fh;
- bool r;
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (f->type != LXC_TYPE_CGFILE) {
- lxcfs_error("%s\n", "Internal error: directory cache info used in cg_write.");
- return -EIO;
+again:
+ if ((now = time(NULL)) < 0) {
+ close(epfd);
+ return false;
}
- if (offset)
- return 0;
-
- localbuf = alloca(size+1);
- localbuf[size] = '\0';
- memcpy(localbuf, buf, size);
-
- if ((k = cgfs_get_key(f->controller, f->cgroup, f->file)) == NULL) {
- size = -EINVAL;
- goto out;
+ deltatime = (starttime + timeout) - now;
+ if (deltatime < 0) { // timeout
+ errno = 0;
+ close(epfd);
+ return false;
}
+ ret = epoll_wait(epfd, &ev, 1, 1000*deltatime + 1);
+ if (ret < 0 && errno == EINTR)
+ goto again;
+ saved_errno = errno;
+ close(epfd);
- if (!fc_may_access(fc, f->controller, f->cgroup, f->file, O_WRONLY)) {
- size = -EACCES;
- goto out;
+ if (ret <= 0) {
+ errno = saved_errno;
+ return false;
}
-
- if (strcmp(f->file, "tasks") == 0 ||
- strcmp(f->file, "/tasks") == 0 ||
- strcmp(f->file, "/cgroup.procs") == 0 ||
- strcmp(f->file, "cgroup.procs") == 0)
- // special case - we have to translate the pids
- r = do_write_pids(fc->pid, fc->uid, f->controller, f->cgroup, f->file, localbuf);
- else
- r = cgfs_set_value(f->controller, f->cgroup, f->file, localbuf);
-
- if (!r)
- size = -EINVAL;
-
-out:
- free_key(k);
- return size;
+ return true;
}
-int cg_chown(const char *path, uid_t uid, gid_t gid)
+static int msgrecv(int sockfd, void *buf, size_t len)
{
- struct fuse_context *fc = fuse_get_context();
- char *cgdir = NULL, *last = NULL, *path1, *path2, *controller;
- struct cgfs_files *k = NULL;
- const char *cgroup;
- int ret;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (strcmp(path, "/cgroup") == 0)
- return -EPERM;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return errno == ENOENT ? -EPERM : -errno;
-
- cgroup = find_cgroup_in_path(path);
- if (!cgroup)
- /* this is just /cgroup/controller */
- return -EPERM;
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
-
- if (!last) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = last;
- }
-
- if (is_child_cgroup(controller, path1, path2)) {
- // get uid, gid, from '/tasks' file and make up a mode
- // That is a hack, until cgmanager gains a GetCgroupPerms fn.
- k = cgfs_get_key(controller, cgroup, "tasks");
-
- } else
- k = cgfs_get_key(controller, path1, path2);
-
- if (!k) {
- ret = -EINVAL;
- goto out;
- }
-
- /*
- * This being a fuse request, the uid and gid must be valid
- * in the caller's namespace. So we can just check to make
- * sure that the caller is root in his uid, and privileged
- * over the file's current owner.
- */
- if (!is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_REQD)) {
- ret = -EACCES;
- goto out;
- }
-
- ret = cgfs_chown_file(controller, cgroup, uid, gid);
-
-out:
- free_key(k);
- free(cgdir);
-
- return ret;
+ if (!wait_for_sock(sockfd, 2))
+ return -1;
+ return recv(sockfd, buf, len, MSG_DONTWAIT);
}
-int cg_chmod(const char *path, mode_t mode)
+static int send_creds(int sock, struct ucred *cred, char v, bool pingfirst)
{
- struct fuse_context *fc = fuse_get_context();
- char * cgdir = NULL, *last = NULL, *path1, *path2, *controller;
- struct cgfs_files *k = NULL;
- const char *cgroup;
- int ret;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- if (strcmp(path, "/cgroup") == 0)
- return -EPERM;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return errno == ENOENT ? -EPERM : -errno;
-
- cgroup = find_cgroup_in_path(path);
- if (!cgroup)
- /* this is just /cgroup/controller */
- return -EPERM;
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
+ struct msghdr msg = { 0 };
+ struct iovec iov;
+ struct cmsghdr *cmsg;
+ char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
+ char buf[1];
+ buf[0] = 'p';
- if (!last) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = last;
+ if (pingfirst) {
+ if (msgrecv(sock, buf, 1) != 1) {
+ lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
+ return SEND_CREDS_FAIL;
+ }
}
- if (is_child_cgroup(controller, path1, path2)) {
- // get uid, gid, from '/tasks' file and make up a mode
- // That is a hack, until cgmanager gains a GetCgroupPerms fn.
- k = cgfs_get_key(controller, cgroup, "tasks");
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
- } else
- k = cgfs_get_key(controller, path1, path2);
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_CREDENTIALS;
+ memcpy(CMSG_DATA(cmsg), cred, sizeof(*cred));
- if (!k) {
- ret = -EINVAL;
- goto out;
- }
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
- /*
- * This being a fuse request, the uid and gid must be valid
- * in the caller's namespace. So we can just check to make
- * sure that the caller is root in his uid, and privileged
- * over the file's current owner.
- */
- if (!is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_OPT)) {
- ret = -EPERM;
- goto out;
- }
+ buf[0] = v;
+ iov.iov_base = buf;
+ iov.iov_len = sizeof(buf);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
- if (!cgfs_chmod_file(controller, cgroup, mode)) {
- ret = -EINVAL;
- goto out;
+ if (sendmsg(sock, &msg, 0) < 0) {
+ lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
+ if (errno == 3)
+ return SEND_CREDS_NOTSK;
+ return SEND_CREDS_FAIL;
}
- ret = 0;
-out:
- free_key(k);
- free(cgdir);
- return ret;
+ return SEND_CREDS_OK;
}
-int cg_mkdir(const char *path, mode_t mode)
+static bool recv_creds(int sock, struct ucred *cred, char *v)
{
- struct fuse_context *fc = fuse_get_context();
- char *last = NULL, *path1, *cgdir = NULL, *controller, *next = NULL;
- const char *cgroup;
+ struct msghdr msg = { 0 };
+ struct iovec iov;
+ struct cmsghdr *cmsg;
+ char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
+ char buf[1];
int ret;
+ int optval = 1;
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return errno == ENOENT ? -EPERM : -errno;
-
- cgroup = find_cgroup_in_path(path);
- if (!cgroup)
- return -errno;
-
- get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!last)
- path1 = "/";
- else
- path1 = cgdir;
+ *v = '1';
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (!caller_is_in_ancestor(initpid, controller, path1, &next)) {
- if (!next)
- ret = -EINVAL;
- else if (last && strcmp(next, last) == 0)
- ret = -EEXIST;
- else
- ret = -EPERM;
- goto out;
- }
+ cred->pid = -1;
+ cred->uid = -1;
+ cred->gid = -1;
- if (!fc_may_access(fc, controller, path1, NULL, O_RDWR)) {
- ret = -EACCES;
- goto out;
+ if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
+ lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
+ return false;
}
- if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
- ret = -EACCES;
- goto out;
+ buf[0] = '1';
+ if (write(sock, buf, 1) != 1) {
+ lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
+ return false;
}
- ret = cgfs_create(controller, cgroup, fc->uid, fc->gid);
-
-out:
- free(cgdir);
- free(next);
- return ret;
-}
-
-int cg_rmdir(const char *path)
-{
- struct fuse_context *fc = fuse_get_context();
- char *last = NULL, *cgdir = NULL, *controller, *next = NULL;
- const char *cgroup;
- int ret;
-
- if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
- return -EIO;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller) /* Someone's trying to delete "/cgroup". */
- return -EPERM;
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) /* Someone's trying to delete a controller e.g. "/blkio". */
- return -EPERM;
+ iov.iov_base = buf;
+ iov.iov_len = sizeof(buf);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
- get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!last) {
- /* Someone's trying to delete a cgroup on the same level as the
- * "/lxc" cgroup e.g. rmdir "/cgroup/blkio/lxc" or
- * rmdir "/cgroup/blkio/init.slice".
- */
- ret = -EPERM;
- goto out;
+ if (!wait_for_sock(sock, 2)) {
+ lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
+ return false;
}
-
- pid_t initpid = lookup_initpid_in_store(fc->pid);
- if (initpid <= 1 || is_shared_pidns(initpid))
- initpid = fc->pid;
- if (!caller_is_in_ancestor(initpid, controller, cgroup, &next)) {
- if (!last || (next && (strcmp(next, last) == 0)))
- ret = -EBUSY;
- else
- ret = -ENOENT;
- goto out;
+ ret = recvmsg(sock, &msg, MSG_DONTWAIT);
+ if (ret < 0) {
+ lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
+ return false;
}
- if (!fc_may_access(fc, controller, cgdir, NULL, O_WRONLY)) {
- ret = -EACCES;
- goto out;
- }
- if (!caller_is_in_ancestor(initpid, controller, cgroup, NULL)) {
- ret = -EACCES;
- goto out;
- }
+ cmsg = CMSG_FIRSTHDR(&msg);
- if (!cgfs_remove(controller, cgroup)) {
- ret = -EINVAL;
- goto out;
+ if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)) &&
+ cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_CREDENTIALS) {
+ memcpy(cred, CMSG_DATA(cmsg), sizeof(*cred));
}
+ *v = buf[0];
- ret = 0;
-
-out:
- free(cgdir);
- free(next);
- return ret;
+ return true;
}
+struct pid_ns_clone_args {
+ int *cpipe;
+ int sock;
+ pid_t tpid;
+ int (*wrapped) (int, pid_t); // pid_from_ns or pid_to_ns
+};
+
static bool startswith(const char *line, const char *pref)
{
if (strncmp(line, pref, strlen(pref)) == 0)
--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#define FUSE_USE_VERSION 26
+
+#define __STDC_FORMAT_MACROS
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <fuse.h>
+#include <inttypes.h>
+#include <libgen.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <wait.h>
+#include <linux/magic.h>
+#include <linux/sched.h>
+#include <sys/epoll.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <sys/sysinfo.h>
+#include <sys/vfs.h>
+
+#include "bindings.h"
+#include "config.h"
+#include "cgroups/cgroup.h"
+#include "cgroups/cgroup_utils.h"
+#include "memory_utils.h"
+#include "utils.h"
+
+struct cgfs_files {
+ char *name;
+ uint32_t uid, gid;
+ uint32_t mode;
+};
+
+struct pid_ns_clone_args {
+ int *cpipe;
+ int sock;
+ pid_t tpid;
+ /* pid_from_ns or pid_to_ns. */
+ int (*wrapped) (int, pid_t);
+};
+
+/*
+ * given /cgroup/freezer/a/b, return "freezer".
+ * the returned char* should NOT be freed.
+ */
+static char *pick_controller_from_path(struct fuse_context *fc, const char *path)
+{
+ const char *p1;
+ char *contr, *slash;
+
+ if (strlen(path) < 9) {
+ errno = EACCES;
+ return NULL;
+ }
+ if (*(path + 7) != '/') {
+ errno = EINVAL;
+ return NULL;
+ }
+ p1 = path + 8;
+ contr = strdupa(p1);
+ if (!contr) {
+ errno = ENOMEM;
+ return NULL;
+ }
+ slash = strstr(contr, "/");
+ if (slash)
+ *slash = '\0';
+
+ for (struct hierarchy **h = cgroup_ops->hierarchies; h && *h; h++) {
+ if ((*h)->__controllers && strcmp((*h)->__controllers, contr) == 0)
+ return (*h)->__controllers;
+ }
+ errno = ENOENT;
+ return NULL;
+}
+
+/*
+ * Find the start of cgroup in /cgroup/controller/the/cgroup/path
+ * Note that the returned value may include files (keynames) etc
+ */
+static const char *find_cgroup_in_path(const char *path)
+{
+ const char *p1;
+
+ if (strlen(path) < 9) {
+ errno = EACCES;
+ return NULL;
+ }
+ p1 = strstr(path + 8, "/");
+ if (!p1) {
+ errno = EINVAL;
+ return NULL;
+ }
+ errno = 0;
+ return p1 + 1;
+}
+
+/*
+ * split the last path element from the path in @cg.
+ * @dir is newly allocated and should be freed, @last not
+*/
+static void get_cgdir_and_path(const char *cg, char **dir, char **last)
+{
+ char *p;
+
+ do {
+ *dir = strdup(cg);
+ } while (!*dir);
+ *last = strrchr(cg, '/');
+ if (!*last) {
+ *last = NULL;
+ return;
+ }
+ p = strrchr(*dir, '/');
+ *p = '\0';
+}
+
+static bool is_child_cgroup(const char *controller, const char *cgroup, const char *f)
+{
+ int cfd;
+ size_t len;
+ char *fnam;
+ int ret;
+ struct stat sb;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cgroup + / + f + \0
+ */
+ len = strlen(cgroup) + strlen(f) + 3;
+ fnam = alloca(len);
+ ret = snprintf(fnam, len, "%s%s/%s", dot_or_empty(cgroup), cgroup, f);
+ if (ret < 0 || (size_t)ret >= len)
+ return false;
+
+ ret = fstatat(cfd, fnam, &sb, 0);
+ if (ret < 0 || !S_ISDIR(sb.st_mode))
+ return false;
+
+ return true;
+}
+
+/*
+ * If pid is in /a/b/c, he may see that /a exists, but not /b or /a/c.
+ */
+static bool caller_may_see_dir(pid_t pid, const char *contrl, const char *cg)
+{
+ bool answer = false;
+ char *c2, *task_cg;
+ size_t target_len, task_len;
+
+ if (strcmp(cg, "/") == 0 || strcmp(cg, "./") == 0)
+ return true;
+
+ c2 = get_pid_cgroup(pid, contrl);
+ if (!c2)
+ return false;
+ prune_init_slice(c2);
+
+ task_cg = c2 + 1;
+ target_len = strlen(cg);
+ task_len = strlen(task_cg);
+ if (task_len == 0) {
+ /* Task is in the root cg, it can see everything. This case is
+ * not handled by the strmcps below, since they test for the
+ * last /, but that is the first / that we've chopped off
+ * above.
+ */
+ answer = true;
+ goto out;
+ }
+ if (strcmp(cg, task_cg) == 0) {
+ answer = true;
+ goto out;
+ }
+ if (target_len < task_len) {
+ /* looking up a parent dir */
+ if (strncmp(task_cg, cg, target_len) == 0 && task_cg[target_len] == '/')
+ answer = true;
+ goto out;
+ }
+ if (target_len > task_len) {
+ /* looking up a child dir */
+ if (strncmp(task_cg, cg, task_len) == 0 && cg[task_len] == '/')
+ answer = true;
+ goto out;
+ }
+
+out:
+ free(c2);
+ return answer;
+}
+
+/*
+ * taskcg is a/b/c
+ * querycg is /a/b/c/d/e
+ * we return 'd'
+ */
+static char *get_next_cgroup_dir(const char *taskcg, const char *querycg)
+{
+ char *start, *end;
+
+ if (strlen(taskcg) <= strlen(querycg)) {
+ lxcfs_error("%s\n", "I was fed bad input.");
+ return NULL;
+ }
+
+ if ((strcmp(querycg, "/") == 0) || (strcmp(querycg, "./") == 0))
+ start = strdup(taskcg + 1);
+ else
+ start = strdup(taskcg + strlen(querycg) + 1);
+ if (!start)
+ return NULL;
+ end = strchr(start, '/');
+ if (end)
+ *end = '\0';
+ return start;
+}
+
+/*
+ * If pid is in /a/b/c/d, he may only act on things under cg=/a/b/c/d.
+ * If pid is in /a, he may act on /a/b, but not on /b.
+ * if the answer is false and nextcg is not NULL, then *nextcg will point
+ * to a string containing the next cgroup directory under cg, which must be
+ * freed by the caller.
+ */
+static bool caller_is_in_ancestor(pid_t pid, const char *contrl, const char *cg, char **nextcg)
+{
+ bool answer = false;
+ char *c2 = get_pid_cgroup(pid, contrl);
+ char *linecmp;
+
+ if (!c2)
+ return false;
+ prune_init_slice(c2);
+
+ /*
+ * callers pass in '/' or './' (openat()) for root cgroup, otherwise
+ * they pass in a cgroup without leading '/'
+ *
+ * The original line here was:
+ * linecmp = *cg == '/' ? c2 : c2+1;
+ * TODO: I'm not sure why you'd want to increment when *cg != '/'?
+ * Serge, do you know?
+ */
+ if (*cg == '/' || !strncmp(cg, "./", 2))
+ linecmp = c2;
+ else
+ linecmp = c2 + 1;
+ if (strncmp(linecmp, cg, strlen(linecmp)) != 0) {
+ if (nextcg) {
+ *nextcg = get_next_cgroup_dir(linecmp, cg);
+ }
+ goto out;
+ }
+ answer = true;
+
+out:
+ free(c2);
+ return answer;
+}
+
+static struct cgfs_files *cgfs_get_key(const char *controller,
+ const char *cgroup, const char *file)
+{
+ int ret, cfd;
+ size_t len;
+ char *fnam;
+ struct stat sb;
+ struct cgfs_files *newkey;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ if (file && *file == '/')
+ file++;
+
+ if (file && strchr(file, '/'))
+ return NULL;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cgroup + / + file + \0
+ */
+ len = strlen(cgroup) + 3;
+ if (file)
+ len += strlen(file) + 1;
+ fnam = alloca(len);
+ snprintf(fnam, len, "%s%s%s%s", dot_or_empty(cgroup), cgroup,
+ file ? "/" : "", file ? file : "");
+
+ ret = fstatat(cfd, fnam, &sb, 0);
+ if (ret < 0)
+ return NULL;
+
+ do {
+ newkey = malloc(sizeof(struct cgfs_files));
+ } while (!newkey);
+ if (file)
+ newkey->name = must_copy_string(file);
+ else if (strrchr(cgroup, '/'))
+ newkey->name = must_copy_string(strrchr(cgroup, '/'));
+ else
+ newkey->name = must_copy_string(cgroup);
+ newkey->uid = sb.st_uid;
+ newkey->gid = sb.st_gid;
+ newkey->mode = sb.st_mode;
+
+ return newkey;
+}
+
+/*
+ * Given a open file * to /proc/pid/{u,g}id_map, and an id
+ * valid in the caller's namespace, return the id mapped into
+ * pid's namespace.
+ * Returns the mapped id, or -1 on error.
+ */
+static unsigned int convert_id_to_ns(FILE *idfile, unsigned int in_id)
+{
+ unsigned int nsuid, // base id for a range in the idfile's namespace
+ hostuid, // base id for a range in the caller's namespace
+ count; // number of ids in this range
+ char line[400];
+ int ret;
+
+ fseek(idfile, 0L, SEEK_SET);
+ while (fgets(line, 400, idfile)) {
+ ret = sscanf(line, "%u %u %u\n", &nsuid, &hostuid, &count);
+ if (ret != 3)
+ continue;
+ if (hostuid + count < hostuid || nsuid + count < nsuid) {
+ /*
+ * uids wrapped around - unexpected as this is a procfile,
+ * so just bail.
+ */
+ lxcfs_error("pid wrapparound at entry %u %u %u in %s\n",
+ nsuid, hostuid, count, line);
+ return -1;
+ }
+ if (hostuid <= in_id && hostuid+count > in_id) {
+ /*
+ * now since hostuid <= in_id < hostuid+count, and
+ * hostuid+count and nsuid+count do not wrap around,
+ * we know that nsuid+(in_id-hostuid) which must be
+ * less that nsuid+(count) must not wrap around
+ */
+ return (in_id - hostuid) + nsuid;
+ }
+ }
+
+ // no answer found
+ return -1;
+}
+
+/*
+ * for is_privileged_over,
+ * specify whether we require the calling uid to be root in his
+ * namespace
+ */
+#define NS_ROOT_REQD true
+#define NS_ROOT_OPT false
+
+#define PROCLEN 100
+
+static bool is_privileged_over(pid_t pid, uid_t uid, uid_t victim, bool req_ns_root)
+{
+ char fpath[PROCLEN];
+ int ret;
+ bool answer = false;
+ uid_t nsuid;
+
+ if (victim == -1 || uid == -1)
+ return false;
+
+ /*
+ * If the request is one not requiring root in the namespace,
+ * then having the same uid suffices. (i.e. uid 1000 has write
+ * access to files owned by uid 1000
+ */
+ if (!req_ns_root && uid == victim)
+ return true;
+
+ ret = snprintf(fpath, PROCLEN, "/proc/%d/uid_map", pid);
+ if (ret < 0 || ret >= PROCLEN)
+ return false;
+ FILE *f = fopen(fpath, "r");
+ if (!f)
+ return false;
+
+ /* if caller's not root in his namespace, reject */
+ nsuid = convert_id_to_ns(f, uid);
+ if (nsuid)
+ goto out;
+
+ /*
+ * If victim is not mapped into caller's ns, reject.
+ * XXX I'm not sure this check is needed given that fuse
+ * will be sending requests where the vfs has converted
+ */
+ nsuid = convert_id_to_ns(f, victim);
+ if (nsuid == -1)
+ goto out;
+
+ answer = true;
+
+out:
+ fclose(f);
+ return answer;
+}
+
+static bool perms_include(int fmode, mode_t req_mode)
+{
+ mode_t r;
+
+ switch (req_mode & O_ACCMODE) {
+ case O_RDONLY:
+ r = S_IROTH;
+ break;
+ case O_WRONLY:
+ r = S_IWOTH;
+ break;
+ case O_RDWR:
+ r = S_IROTH | S_IWOTH;
+ break;
+ default:
+ return false;
+ }
+ return ((fmode & r) == r);
+}
+
+static void free_key(struct cgfs_files *k)
+{
+ if (!k)
+ return;
+ free_disarm(k->name);
+ free_disarm(k);
+}
+
+/*
+ * check whether a fuse context may access a cgroup dir or file
+ *
+ * If file is not null, it is a cgroup file to check under cg.
+ * If file is null, then we are checking perms on cg itself.
+ *
+ * For files we can check the mode of the list_keys result.
+ * For cgroups, we must make assumptions based on the files under the
+ * cgroup, because cgmanager doesn't tell us ownership/perms of cgroups
+ * yet.
+ */
+static bool fc_may_access(struct fuse_context *fc, const char *contrl, const char *cg, const char *file, mode_t mode)
+{
+ struct cgfs_files *k = NULL;
+ bool ret = false;
+
+ k = cgfs_get_key(contrl, cg, file);
+ if (!k)
+ return false;
+
+ if (is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_OPT)) {
+ if (perms_include(k->mode >> 6, mode)) {
+ ret = true;
+ goto out;
+ }
+ }
+ if (fc->gid == k->gid) {
+ if (perms_include(k->mode >> 3, mode)) {
+ ret = true;
+ goto out;
+ }
+ }
+ ret = perms_include(k->mode, mode);
+
+out:
+ free_key(k);
+ return ret;
+}
+
+int cg_getattr(const char *path, struct stat *sb)
+{
+ struct timespec now;
+ struct fuse_context *fc = fuse_get_context();
+ char * cgdir = NULL;
+ char *last = NULL, *path1, *path2;
+ struct cgfs_files *k = NULL;
+ const char *cgroup;
+ const char *controller = NULL;
+ int ret = -ENOENT;
+
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ memset(sb, 0, sizeof(struct stat));
+
+ if (clock_gettime(CLOCK_REALTIME, &now) < 0)
+ return -EINVAL;
+
+ sb->st_uid = sb->st_gid = 0;
+ sb->st_atim = sb->st_mtim = sb->st_ctim = now;
+ sb->st_size = 0;
+
+ if (strcmp(path, "/cgroup") == 0) {
+ sb->st_mode = S_IFDIR | 00755;
+ sb->st_nlink = 2;
+ return 0;
+ }
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return -errno;
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup) {
+ /* this is just /cgroup/controller, return it as a dir */
+ sb->st_mode = S_IFDIR | 00755;
+ sb->st_nlink = 2;
+ return 0;
+ }
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+
+ if (!last) {
+ path1 = "/";
+ path2 = cgdir;
+ } else {
+ path1 = cgdir;
+ path2 = last;
+ }
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ /* check that cgcopy is either a child cgroup of cgdir, or listed in its keys.
+ * Then check that caller's cgroup is under path if last is a child
+ * cgroup, or cgdir if last is a file */
+
+ if (is_child_cgroup(controller, path1, path2)) {
+ if (!caller_may_see_dir(initpid, controller, cgroup)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ if (!caller_is_in_ancestor(initpid, controller, cgroup, NULL)) {
+ /* this is just /cgroup/controller, return it as a dir */
+ sb->st_mode = S_IFDIR | 00555;
+ sb->st_nlink = 2;
+ ret = 0;
+ goto out;
+ }
+ if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ // get uid, gid, from '/tasks' file and make up a mode
+ // That is a hack, until cgmanager gains a GetCgroupPerms fn.
+ sb->st_mode = S_IFDIR | 00755;
+ k = cgfs_get_key(controller, cgroup, NULL);
+ if (!k) {
+ sb->st_uid = sb->st_gid = 0;
+ } else {
+ sb->st_uid = k->uid;
+ sb->st_gid = k->gid;
+ }
+ free_key(k);
+ sb->st_nlink = 2;
+ ret = 0;
+ goto out;
+ }
+
+ if ((k = cgfs_get_key(controller, path1, path2)) != NULL) {
+ sb->st_mode = S_IFREG | k->mode;
+ sb->st_nlink = 1;
+ sb->st_uid = k->uid;
+ sb->st_gid = k->gid;
+ sb->st_size = 0;
+ free_key(k);
+ if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ ret = 0;
+ }
+
+out:
+ free(cgdir);
+ return ret;
+}
+
+/*
+ * Chown all the files in the cgroup directory. We do this when we create a
+ * cgroup on behalf of a user.
+ */
+static void chown_all_cgroup_files(const char *dirname, uid_t uid, gid_t gid, int fd)
+{
+ struct dirent *direntp;
+ char path[MAXPATHLEN];
+ size_t len;
+ DIR *d;
+ int fd1, ret;
+
+ len = strlen(dirname);
+ if (len >= MAXPATHLEN) {
+ lxcfs_error("Pathname too long: %s\n", dirname);
+ return;
+ }
+
+ fd1 = openat(fd, dirname, O_DIRECTORY);
+ if (fd1 < 0)
+ return;
+
+ d = fdopendir(fd1);
+ if (!d) {
+ lxcfs_error("Failed to open %s\n", dirname);
+ return;
+ }
+
+ while ((direntp = readdir(d))) {
+ if (!strcmp(direntp->d_name, ".") || !strcmp(direntp->d_name, ".."))
+ continue;
+ ret = snprintf(path, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
+ if (ret < 0 || ret >= MAXPATHLEN) {
+ lxcfs_error("Pathname too long under %s\n", dirname);
+ continue;
+ }
+ if (fchownat(fd, path, uid, gid, 0) < 0)
+ lxcfs_error("Failed to chown file %s to %u:%u", path, uid, gid);
+ }
+ closedir(d);
+}
+
+static int cgfs_create(const char *controller, const char *cg, uid_t uid, gid_t gid)
+{
+ int cfd;
+ size_t len;
+ char *dirnam;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return -EINVAL;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cg + \0
+ */
+ len = strlen(cg) + 2;
+ dirnam = alloca(len);
+ snprintf(dirnam, len, "%s%s", dot_or_empty(cg), cg);
+
+ if (mkdirat(cfd, dirnam, 0755) < 0)
+ return -errno;
+
+ if (uid == 0 && gid == 0)
+ return 0;
+
+ if (fchownat(cfd, dirnam, uid, gid, 0) < 0)
+ return -errno;
+
+ chown_all_cgroup_files(dirnam, uid, gid, cfd);
+
+ return 0;
+}
+
+int cg_mkdir(const char *path, mode_t mode)
+{
+ struct fuse_context *fc = fuse_get_context();
+ char *last = NULL, *path1, *cgdir = NULL, *controller, *next = NULL;
+ const char *cgroup;
+ int ret;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return errno == ENOENT ? -EPERM : -errno;
+
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup)
+ return -errno;
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last)
+ path1 = "/";
+ else
+ path1 = cgdir;
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (!caller_is_in_ancestor(initpid, controller, path1, &next)) {
+ if (!next)
+ ret = -EINVAL;
+ else if (last && strcmp(next, last) == 0)
+ ret = -EEXIST;
+ else
+ ret = -EPERM;
+ goto out;
+ }
+
+ if (!fc_may_access(fc, controller, path1, NULL, O_RDWR)) {
+ ret = -EACCES;
+ goto out;
+ }
+ if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ ret = cgfs_create(controller, cgroup, fc->uid, fc->gid);
+
+out:
+ free(cgdir);
+ free(next);
+ return ret;
+}
+
+static bool recursive_rmdir(const char *dirname, int fd, const int cfd)
+{
+ struct dirent *direntp;
+ DIR *dir;
+ bool ret = false;
+ char pathname[MAXPATHLEN];
+ int dupfd;
+
+ dupfd = dup(fd); // fdopendir() does bad things once it uses an fd.
+ if (dupfd < 0)
+ return false;
+
+ dir = fdopendir(dupfd);
+ if (!dir) {
+ lxcfs_debug("Failed to open %s: %s.\n", dirname, strerror(errno));
+ close(dupfd);
+ return false;
+ }
+
+ while ((direntp = readdir(dir))) {
+ struct stat mystat;
+ int rc;
+
+ if (!strcmp(direntp->d_name, ".") ||
+ !strcmp(direntp->d_name, ".."))
+ continue;
+
+ rc = snprintf(pathname, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
+ if (rc < 0 || rc >= MAXPATHLEN) {
+ lxcfs_error("%s\n", "Pathname too long.");
+ continue;
+ }
+
+ rc = fstatat(cfd, pathname, &mystat, AT_SYMLINK_NOFOLLOW);
+ if (rc) {
+ lxcfs_debug("Failed to stat %s: %s.\n", pathname, strerror(errno));
+ continue;
+ }
+ if (S_ISDIR(mystat.st_mode))
+ if (!recursive_rmdir(pathname, fd, cfd))
+ lxcfs_debug("Error removing %s.\n", pathname);
+ }
+
+ ret = true;
+ if (closedir(dir) < 0) {
+ lxcfs_error("Failed to close directory %s: %s\n", dirname, strerror(errno));
+ ret = false;
+ }
+
+ if (unlinkat(cfd, dirname, AT_REMOVEDIR) < 0) {
+ lxcfs_debug("Failed to delete %s: %s.\n", dirname, strerror(errno));
+ ret = false;
+ }
+
+ close(dupfd);
+
+ return ret;
+}
+
+static bool cgfs_remove(const char *controller, const char *cg)
+{
+ int fd, cfd;
+ size_t len;
+ char *dirnam;
+ bool bret;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cg + \0
+ */
+ len = strlen(cg) + 2;
+ dirnam = alloca(len);
+ snprintf(dirnam, len, "%s%s", dot_or_empty(cg), cg);
+
+ fd = openat(cfd, dirnam, O_DIRECTORY);
+ if (fd < 0)
+ return false;
+
+ bret = recursive_rmdir(dirnam, fd, cfd);
+ close(fd);
+ return bret;
+}
+
+int cg_rmdir(const char *path)
+{
+ struct fuse_context *fc = fuse_get_context();
+ char *last = NULL, *cgdir = NULL, *controller, *next = NULL;
+ const char *cgroup;
+ int ret;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller) /* Someone's trying to delete "/cgroup". */
+ return -EPERM;
+
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup) /* Someone's trying to delete a controller e.g. "/blkio". */
+ return -EPERM;
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last) {
+ /* Someone's trying to delete a cgroup on the same level as the
+ * "/lxc" cgroup e.g. rmdir "/cgroup/blkio/lxc" or
+ * rmdir "/cgroup/blkio/init.slice".
+ */
+ ret = -EPERM;
+ goto out;
+ }
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (!caller_is_in_ancestor(initpid, controller, cgroup, &next)) {
+ if (!last || (next && (strcmp(next, last) == 0)))
+ ret = -EBUSY;
+ else
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (!fc_may_access(fc, controller, cgdir, NULL, O_WRONLY)) {
+ ret = -EACCES;
+ goto out;
+ }
+ if (!caller_is_in_ancestor(initpid, controller, cgroup, NULL)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ if (!cgfs_remove(controller, cgroup)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = 0;
+
+out:
+ free(cgdir);
+ free(next);
+ return ret;
+}
+
+static bool cgfs_chmod_file(const char *controller, const char *file, mode_t mode)
+{
+ int cfd;
+ size_t len;
+ char *pathname;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /file + \0
+ */
+ len = strlen(file) + 2;
+ pathname = alloca(len);
+ snprintf(pathname, len, "%s%s", dot_or_empty(file), file);
+ if (fchmodat(cfd, pathname, mode, 0) < 0)
+ return false;
+ return true;
+}
+
+int cg_chmod(const char *path, mode_t mode)
+{
+ struct fuse_context *fc = fuse_get_context();
+ char * cgdir = NULL, *last = NULL, *path1, *path2, *controller;
+ struct cgfs_files *k = NULL;
+ const char *cgroup;
+ int ret;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (strcmp(path, "/cgroup") == 0)
+ return -EPERM;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return errno == ENOENT ? -EPERM : -errno;
+
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup)
+ /* this is just /cgroup/controller */
+ return -EPERM;
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+
+ if (!last) {
+ path1 = "/";
+ path2 = cgdir;
+ } else {
+ path1 = cgdir;
+ path2 = last;
+ }
+
+ if (is_child_cgroup(controller, path1, path2)) {
+ // get uid, gid, from '/tasks' file and make up a mode
+ // That is a hack, until cgmanager gains a GetCgroupPerms fn.
+ k = cgfs_get_key(controller, cgroup, "tasks");
+
+ } else
+ k = cgfs_get_key(controller, path1, path2);
+
+ if (!k) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * This being a fuse request, the uid and gid must be valid
+ * in the caller's namespace. So we can just check to make
+ * sure that the caller is root in his uid, and privileged
+ * over the file's current owner.
+ */
+ if (!is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_OPT)) {
+ ret = -EPERM;
+ goto out;
+ }
+
+ if (!cgfs_chmod_file(controller, cgroup, mode)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = 0;
+out:
+ free_key(k);
+ free(cgdir);
+ return ret;
+}
+
+static int is_dir(const char *path, int fd)
+{
+ struct stat statbuf;
+ int ret = fstatat(fd, path, &statbuf, fd);
+ if (ret == 0 && S_ISDIR(statbuf.st_mode))
+ return 1;
+ return 0;
+}
+
+static int chown_tasks_files(const char *dirname, uid_t uid, gid_t gid, int fd)
+{
+ size_t len;
+ char *fname;
+
+ len = strlen(dirname) + strlen("/cgroup.procs") + 1;
+ fname = alloca(len);
+ snprintf(fname, len, "%s/tasks", dirname);
+ if (fchownat(fd, fname, uid, gid, 0) != 0)
+ return -errno;
+ snprintf(fname, len, "%s/cgroup.procs", dirname);
+ if (fchownat(fd, fname, uid, gid, 0) != 0)
+ return -errno;
+ return 0;
+}
+
+static int cgfs_chown_file(const char *controller, const char *file, uid_t uid,
+ gid_t gid)
+{
+ int cfd;
+ size_t len;
+ char *pathname;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /file + \0
+ */
+ len = strlen(file) + 2;
+ pathname = alloca(len);
+ snprintf(pathname, len, "%s%s", dot_or_empty(file), file);
+ if (fchownat(cfd, pathname, uid, gid, 0) < 0)
+ return -errno;
+
+ if (is_dir(pathname, cfd))
+ return chown_tasks_files(pathname, uid, gid, cfd);
+
+ return 0;
+}
+
+int cg_chown(const char *path, uid_t uid, gid_t gid)
+{
+ struct fuse_context *fc = fuse_get_context();
+ char *cgdir = NULL, *last = NULL, *path1, *path2, *controller;
+ struct cgfs_files *k = NULL;
+ const char *cgroup;
+ int ret;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (strcmp(path, "/cgroup") == 0)
+ return -EPERM;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return errno == ENOENT ? -EPERM : -errno;
+
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup)
+ /* this is just /cgroup/controller */
+ return -EPERM;
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+
+ if (!last) {
+ path1 = "/";
+ path2 = cgdir;
+ } else {
+ path1 = cgdir;
+ path2 = last;
+ }
+
+ if (is_child_cgroup(controller, path1, path2)) {
+ // get uid, gid, from '/tasks' file and make up a mode
+ // That is a hack, until cgmanager gains a GetCgroupPerms fn.
+ k = cgfs_get_key(controller, cgroup, "tasks");
+
+ } else
+ k = cgfs_get_key(controller, path1, path2);
+
+ if (!k) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * This being a fuse request, the uid and gid must be valid
+ * in the caller's namespace. So we can just check to make
+ * sure that the caller is root in his uid, and privileged
+ * over the file's current owner.
+ */
+ if (!is_privileged_over(fc->pid, fc->uid, k->uid, NS_ROOT_REQD)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ ret = cgfs_chown_file(controller, cgroup, uid, gid);
+
+out:
+ free_key(k);
+ free(cgdir);
+
+ return ret;
+}
+
+int cg_open(const char *path, struct fuse_file_info *fi)
+{
+ const char *cgroup;
+ char *last = NULL, *path1, *path2, * cgdir = NULL, *controller;
+ struct cgfs_files *k = NULL;
+ struct file_info *file_info;
+ struct fuse_context *fc = fuse_get_context();
+ int ret;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return -errno;
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup)
+ return -errno;
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last) {
+ path1 = "/";
+ path2 = cgdir;
+ } else {
+ path1 = cgdir;
+ path2 = last;
+ }
+
+ k = cgfs_get_key(controller, path1, path2);
+ if (!k) {
+ ret = -EINVAL;
+ goto out;
+ }
+ free_key(k);
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (!caller_may_see_dir(initpid, controller, path1)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ if (!fc_may_access(fc, controller, path1, path2, fi->flags)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ /* we'll free this at cg_release */
+ file_info = malloc(sizeof(*file_info));
+ if (!file_info) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ file_info->controller = must_copy_string(controller);
+ file_info->cgroup = must_copy_string(path1);
+ file_info->file = must_copy_string(path2);
+ file_info->type = LXC_TYPE_CGFILE;
+ file_info->buf = NULL;
+ file_info->buflen = 0;
+
+ fi->fh = (unsigned long)file_info;
+ ret = 0;
+
+out:
+ free(cgdir);
+ return ret;
+}
+
+#define POLLIN_SET ( EPOLLIN | EPOLLHUP | EPOLLRDHUP )
+
+static bool wait_for_sock(int sock, int timeout)
+{
+ struct epoll_event ev;
+ int epfd, ret, now, starttime, deltatime, saved_errno;
+
+ if ((starttime = time(NULL)) < 0)
+ return false;
+
+ if ((epfd = epoll_create(1)) < 0) {
+ lxcfs_error("%s\n", "Failed to create epoll socket: %m.");
+ return false;
+ }
+
+ ev.events = POLLIN_SET;
+ ev.data.fd = sock;
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
+ lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
+ close(epfd);
+ return false;
+ }
+
+again:
+ if ((now = time(NULL)) < 0) {
+ close(epfd);
+ return false;
+ }
+
+ deltatime = (starttime + timeout) - now;
+ if (deltatime < 0) { // timeout
+ errno = 0;
+ close(epfd);
+ return false;
+ }
+ ret = epoll_wait(epfd, &ev, 1, 1000*deltatime + 1);
+ if (ret < 0 && errno == EINTR)
+ goto again;
+ saved_errno = errno;
+ close(epfd);
+
+ if (ret <= 0) {
+ errno = saved_errno;
+ return false;
+ }
+ return true;
+}
+
+static int msgrecv(int sockfd, void *buf, size_t len)
+{
+ if (!wait_for_sock(sockfd, 2))
+ return -1;
+ return recv(sockfd, buf, len, MSG_DONTWAIT);
+}
+
+#define SEND_CREDS_OK 0
+#define SEND_CREDS_NOTSK 1
+#define SEND_CREDS_FAIL 2
+
+static int send_creds(int sock, struct ucred *cred, char v, bool pingfirst)
+{
+ struct msghdr msg = { 0 };
+ struct iovec iov;
+ struct cmsghdr *cmsg;
+ char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
+ char buf[1];
+ buf[0] = 'p';
+
+ if (pingfirst) {
+ if (msgrecv(sock, buf, 1) != 1) {
+ lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
+ return SEND_CREDS_FAIL;
+ }
+ }
+
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_CREDENTIALS;
+ memcpy(CMSG_DATA(cmsg), cred, sizeof(*cred));
+
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+
+ buf[0] = v;
+ iov.iov_base = buf;
+ iov.iov_len = sizeof(buf);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ if (sendmsg(sock, &msg, 0) < 0) {
+ lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
+ if (errno == 3)
+ return SEND_CREDS_NOTSK;
+ return SEND_CREDS_FAIL;
+ }
+
+ return SEND_CREDS_OK;
+}
+
+static int wait_for_pid(pid_t pid)
+{
+ int status, ret;
+
+ if (pid <= 0)
+ return -1;
+
+again:
+ ret = waitpid(pid, &status, 0);
+ if (ret == -1) {
+ if (errno == EINTR)
+ goto again;
+ return -1;
+ }
+ if (ret != pid)
+ goto again;
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+ return -1;
+ return 0;
+}
+
+static bool recv_creds(int sock, struct ucred *cred, char *v)
+{
+ struct msghdr msg = { 0 };
+ struct iovec iov;
+ struct cmsghdr *cmsg;
+ char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
+ char buf[1];
+ int ret;
+ int optval = 1;
+
+ *v = '1';
+
+ cred->pid = -1;
+ cred->uid = -1;
+ cred->gid = -1;
+
+ if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
+ lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
+ return false;
+ }
+ buf[0] = '1';
+ if (write(sock, buf, 1) != 1) {
+ lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
+ return false;
+ }
+
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
+
+ iov.iov_base = buf;
+ iov.iov_len = sizeof(buf);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ if (!wait_for_sock(sock, 2)) {
+ lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
+ return false;
+ }
+ ret = recvmsg(sock, &msg, MSG_DONTWAIT);
+ if (ret < 0) {
+ lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
+ return false;
+ }
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+
+ if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)) &&
+ cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_CREDENTIALS) {
+ memcpy(cred, CMSG_DATA(cmsg), sizeof(*cred));
+ }
+ *v = buf[0];
+
+ return true;
+}
+
+/*
+ * pid_to_ns - reads pids from a ucred over a socket, then writes the
+ * int value back over the socket. This shifts the pid from the
+ * sender's pidns into tpid's pidns.
+ */
+static int pid_to_ns(int sock, pid_t tpid)
+{
+ char v = '0';
+ struct ucred cred;
+
+ while (recv_creds(sock, &cred, &v)) {
+ if (v == '1')
+ return 0;
+
+ if (write(sock, &cred.pid, sizeof(pid_t)) != sizeof(pid_t))
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * pid_ns_clone_wrapper - wraps pid_to_ns or pid_from_ns for usage
+ * with clone(). This simply writes '1' as ACK back to the parent
+ * before calling the actual wrapped function.
+ */
+static int pid_ns_clone_wrapper(void *arg) {
+ struct pid_ns_clone_args* args = (struct pid_ns_clone_args *) arg;
+ char b = '1';
+
+ close(args->cpipe[0]);
+ if (write(args->cpipe[1], &b, sizeof(char)) < 0)
+ lxcfs_error("(child): error on write: %s.\n", strerror(errno));
+ close(args->cpipe[1]);
+ return args->wrapped(args->sock, args->tpid);
+}
+
+/*
+ * pid_to_ns_wrapper: when you setns into a pidns, you yourself remain
+ * in your old pidns. Only children which you clone will be in the target
+ * pidns. So the pid_to_ns_wrapper does the setns, then clones a child to
+ * actually convert pids.
+ *
+ * Note: glibc's fork() does not respect pidns, which can lead to failed
+ * assertions inside glibc (and thus failed forks) if the child's pid in
+ * the pidns and the parent pid outside are identical. Using clone prevents
+ * this issue.
+ */
+static void pid_to_ns_wrapper(int sock, pid_t tpid)
+{
+ int newnsfd = -1, ret, cpipe[2];
+ char fnam[100];
+ pid_t cpid;
+ char v;
+
+ ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
+ if (ret < 0 || ret >= sizeof(fnam))
+ _exit(1);
+ newnsfd = open(fnam, O_RDONLY);
+ if (newnsfd < 0)
+ _exit(1);
+ if (setns(newnsfd, 0) < 0)
+ _exit(1);
+ close(newnsfd);
+
+ if (pipe(cpipe) < 0)
+ _exit(1);
+
+ struct pid_ns_clone_args args = {
+ .cpipe = cpipe,
+ .sock = sock,
+ .tpid = tpid,
+ .wrapped = &pid_to_ns
+ };
+ size_t stack_size = sysconf(_SC_PAGESIZE);
+ void *stack = alloca(stack_size);
+
+ cpid = clone(pid_ns_clone_wrapper, stack + stack_size, SIGCHLD, &args);
+ if (cpid < 0)
+ _exit(1);
+
+ /* Give the child 1 second to be done forking and write its ack. */
+ if (!wait_for_sock(cpipe[0], 1))
+ _exit(1);
+ ret = read(cpipe[0], &v, 1);
+ if (ret != sizeof(char) || v != '1')
+ _exit(1);
+
+ if (!wait_for_pid(cpid))
+ _exit(1);
+ _exit(0);
+}
+
+/*
+ * append pid to *src.
+ * src: a pointer to a char* in which ot append the pid.
+ * sz: the number of characters printed so far, minus trailing \0.
+ * asz: the allocated size so far
+ * pid: the pid to append
+ */
+static void must_strcat_pid(char **src, size_t *sz, size_t *asz, pid_t pid)
+{
+ must_strcat(src, sz, asz, "%d\n", (int)pid);
+}
+
+/*
+ * To read cgroup files with a particular pid, we will setns into the child
+ * pidns, open a pipe, fork a child - which will be the first to really be in
+ * the child ns - which does the cgfs_get_value and writes the data to the pipe.
+ */
+static bool do_read_pids(pid_t tpid, const char *contrl, const char *cg,
+ const char *file, char **d)
+{
+ int sock[2] = {-1, -1};
+ char *tmpdata = NULL;
+ int ret;
+ pid_t qpid, cpid = -1;
+ bool answer = false;
+ char v = '0';
+ struct ucred cred;
+ size_t sz = 0, asz = 0;
+
+ if (!cgroup_ops->get(cgroup_ops, contrl, cg, file, &tmpdata))
+ return false;
+
+ /*
+ * Now we read the pids from returned data one by one, pass
+ * them into a child in the target namespace, read back the
+ * translated pids, and put them into our to-return data
+ */
+
+ if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
+ perror("socketpair");
+ free(tmpdata);
+ return false;
+ }
+
+ cpid = fork();
+ if (cpid == -1)
+ goto out;
+
+ if (!cpid) // child - exits when done
+ pid_to_ns_wrapper(sock[1], tpid);
+
+ char *ptr = tmpdata;
+ cred.uid = 0;
+ cred.gid = 0;
+ while (sscanf(ptr, "%d\n", &qpid) == 1) {
+ cred.pid = qpid;
+ ret = send_creds(sock[0], &cred, v, true);
+
+ if (ret == SEND_CREDS_NOTSK)
+ goto next;
+ if (ret == SEND_CREDS_FAIL)
+ goto out;
+
+ // read converted results
+ if (!wait_for_sock(sock[0], 2)) {
+ lxcfs_error("Timed out waiting for pid from child: %s.\n", strerror(errno));
+ goto out;
+ }
+ if (read(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
+ lxcfs_error("Error reading pid from child: %s.\n", strerror(errno));
+ goto out;
+ }
+ must_strcat_pid(d, &sz, &asz, qpid);
+next:
+ ptr = strchr(ptr, '\n');
+ if (!ptr)
+ break;
+ ptr++;
+ }
+
+ cred.pid = getpid();
+ v = '1';
+ if (send_creds(sock[0], &cred, v, true) != SEND_CREDS_OK) {
+ // failed to ask child to exit
+ lxcfs_error("Failed to ask child to exit: %s.\n", strerror(errno));
+ goto out;
+ }
+
+ answer = true;
+
+out:
+ free(tmpdata);
+ if (cpid != -1)
+ wait_for_pid(cpid);
+ if (sock[0] != -1) {
+ close(sock[0]);
+ close(sock[1]);
+ }
+ return answer;
+}
+
+int cg_read(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
+{
+ struct fuse_context *fc = fuse_get_context();
+ struct file_info *f = (struct file_info *)fi->fh;
+ struct cgfs_files *k = NULL;
+ char *data = NULL;
+ int ret, s;
+ bool r;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (f->type != LXC_TYPE_CGFILE) {
+ lxcfs_error("%s\n", "Internal error: directory cache info used in cg_read.");
+ return -EIO;
+ }
+
+ if (offset)
+ return 0;
+
+ if (!f->controller)
+ return -EINVAL;
+
+ if ((k = cgfs_get_key(f->controller, f->cgroup, f->file)) == NULL) {
+ return -EINVAL;
+ }
+ free_key(k);
+
+
+ if (!fc_may_access(fc, f->controller, f->cgroup, f->file, O_RDONLY)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ if (strcmp(f->file, "tasks") == 0 ||
+ strcmp(f->file, "/tasks") == 0 ||
+ strcmp(f->file, "/cgroup.procs") == 0 ||
+ strcmp(f->file, "cgroup.procs") == 0)
+ // special case - we have to translate the pids
+ r = do_read_pids(fc->pid, f->controller, f->cgroup, f->file, &data);
+ else
+ r = cgroup_ops->get(cgroup_ops, f->controller, f->cgroup, f->file, &data);
+
+ if (!r) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (!data) {
+ ret = 0;
+ goto out;
+ }
+ s = strlen(data);
+ if (s > size)
+ s = size;
+ memcpy(buf, data, s);
+ if (s > 0 && s < size && data[s-1] != '\n')
+ buf[s++] = '\n';
+
+ ret = s;
+
+out:
+ free(data);
+ return ret;
+}
+
+int cg_opendir(const char *path, struct fuse_file_info *fi)
+{
+ struct fuse_context *fc = fuse_get_context();
+ const char *cgroup;
+ struct file_info *dir_info;
+ char *controller = NULL;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (strcmp(path, "/cgroup") == 0) {
+ cgroup = NULL;
+ controller = NULL;
+ } else {
+ // return list of keys for the controller, and list of child cgroups
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return -errno;
+
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup) {
+ /* this is just /cgroup/controller, return its contents */
+ cgroup = "/";
+ }
+ }
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (cgroup) {
+ if (!caller_may_see_dir(initpid, controller, cgroup))
+ return -ENOENT;
+ if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY))
+ return -EACCES;
+ }
+
+ /* we'll free this at cg_releasedir */
+ dir_info = malloc(sizeof(*dir_info));
+ if (!dir_info)
+ return -ENOMEM;
+ dir_info->controller = must_copy_string(controller);
+ dir_info->cgroup = must_copy_string(cgroup);
+ dir_info->type = LXC_TYPE_CGDIR;
+ dir_info->buf = NULL;
+ dir_info->file = NULL;
+ dir_info->buflen = 0;
+
+ fi->fh = (unsigned long)dir_info;
+ return 0;
+}
+
+int cg_release(const char *path, struct fuse_file_info *fi)
+{
+ do_release_file_info(fi);
+ return 0;
+}
+
+int cg_releasedir(const char *path, struct fuse_file_info *fi)
+{
+ do_release_file_info(fi);
+ return 0;
+}
+
+static FILE *open_pids_file(const char *controller, const char *cgroup)
+{
+ int fd, cfd;
+ size_t len;
+ char *pathname;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cgroup + / "cgroup.procs" + \0
+ */
+ len = strlen(cgroup) + strlen("cgroup.procs") + 3;
+ pathname = alloca(len);
+ snprintf(pathname, len, "%s%s/cgroup.procs", dot_or_empty(cgroup), cgroup);
+
+ fd = openat(cfd, pathname, O_WRONLY);
+ if (fd < 0)
+ return NULL;
+
+ return fdopen(fd, "w");
+}
+
+static int pid_from_ns(int sock, pid_t tpid)
+{
+ pid_t vpid;
+ struct ucred cred;
+ char v;
+ int ret;
+
+ cred.uid = 0;
+ cred.gid = 0;
+ while (1) {
+ if (!wait_for_sock(sock, 2)) {
+ lxcfs_error("%s\n", "Timeout reading from parent.");
+ return 1;
+ }
+ if ((ret = read(sock, &vpid, sizeof(pid_t))) != sizeof(pid_t)) {
+ lxcfs_error("Bad read from parent: %s.\n", strerror(errno));
+ return 1;
+ }
+ if (vpid == -1) // done
+ break;
+ v = '0';
+ cred.pid = vpid;
+ if (send_creds(sock, &cred, v, true) != SEND_CREDS_OK) {
+ v = '1';
+ cred.pid = getpid();
+ if (send_creds(sock, &cred, v, false) != SEND_CREDS_OK)
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static void pid_from_ns_wrapper(int sock, pid_t tpid)
+{
+ int newnsfd = -1, ret, cpipe[2];
+ char fnam[100];
+ pid_t cpid;
+ char v;
+
+ ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
+ if (ret < 0 || ret >= sizeof(fnam))
+ _exit(1);
+ newnsfd = open(fnam, O_RDONLY);
+ if (newnsfd < 0)
+ _exit(1);
+ if (setns(newnsfd, 0) < 0)
+ _exit(1);
+ close(newnsfd);
+
+ if (pipe(cpipe) < 0)
+ _exit(1);
+
+ struct pid_ns_clone_args args = {
+ .cpipe = cpipe,
+ .sock = sock,
+ .tpid = tpid,
+ .wrapped = &pid_from_ns
+ };
+ size_t stack_size = sysconf(_SC_PAGESIZE);
+ void *stack = alloca(stack_size);
+
+ cpid = clone(pid_ns_clone_wrapper, stack + stack_size, SIGCHLD, &args);
+ if (cpid < 0)
+ _exit(1);
+
+ // give the child 1 second to be done forking and
+ // write its ack
+ if (!wait_for_sock(cpipe[0], 1))
+ _exit(1);
+ ret = read(cpipe[0], &v, 1);
+ if (ret != sizeof(char) || v != '1')
+ _exit(1);
+
+ if (!wait_for_pid(cpid))
+ _exit(1);
+ _exit(0);
+}
+
+/*
+ * get_pid_creds: get the real uid and gid of @pid from
+ * /proc/$$/status
+ * (XXX should we use euid here?)
+ */
+static void get_pid_creds(pid_t pid, uid_t *uid, gid_t *gid)
+{
+ char line[400];
+ uid_t u;
+ gid_t g;
+ FILE *f;
+
+ *uid = -1;
+ *gid = -1;
+ sprintf(line, "/proc/%d/status", pid);
+ if ((f = fopen(line, "r")) == NULL) {
+ lxcfs_error("Error opening %s: %s\n", line, strerror(errno));
+ return;
+ }
+ while (fgets(line, 400, f)) {
+ if (strncmp(line, "Uid:", 4) == 0) {
+ if (sscanf(line+4, "%u", &u) != 1) {
+ lxcfs_error("bad uid line for pid %u\n", pid);
+ fclose(f);
+ return;
+ }
+ *uid = u;
+ } else if (strncmp(line, "Gid:", 4) == 0) {
+ if (sscanf(line+4, "%u", &g) != 1) {
+ lxcfs_error("bad gid line for pid %u\n", pid);
+ fclose(f);
+ return;
+ }
+ *gid = g;
+ }
+ }
+ fclose(f);
+}
+
+/*
+ * Given host @uid, return the uid to which it maps in
+ * @pid's user namespace, or -1 if none.
+ */
+static bool hostuid_to_ns(uid_t uid, pid_t pid, uid_t *answer)
+{
+ FILE *f;
+ char line[400];
+
+ sprintf(line, "/proc/%d/uid_map", pid);
+ if ((f = fopen(line, "r")) == NULL) {
+ return false;
+ }
+
+ *answer = convert_id_to_ns(f, uid);
+ fclose(f);
+
+ if (*answer == -1)
+ return false;
+ return true;
+}
+
+/*
+ * May the requestor @r move victim @v to a new cgroup?
+ * This is allowed if
+ * . they are the same task
+ * . they are ownedy by the same uid
+ * . @r is root on the host, or
+ * . @v's uid is mapped into @r's where @r is root.
+ */
+static bool may_move_pid(pid_t r, uid_t r_uid, pid_t v)
+{
+ uid_t v_uid, tmpuid;
+ gid_t v_gid;
+
+ if (r == v)
+ return true;
+ if (r_uid == 0)
+ return true;
+ get_pid_creds(v, &v_uid, &v_gid);
+ if (r_uid == v_uid)
+ return true;
+ if (hostuid_to_ns(r_uid, r, &tmpuid) && tmpuid == 0
+ && hostuid_to_ns(v_uid, r, &tmpuid))
+ return true;
+ return false;
+}
+
+static bool do_write_pids(pid_t tpid, uid_t tuid, const char *contrl,
+ const char *cg, const char *file, const char *buf)
+{
+ int sock[2] = {-1, -1};
+ pid_t qpid, cpid = -1;
+ FILE *pids_file = NULL;
+ bool answer = false, fail = false;
+
+ pids_file = open_pids_file(contrl, cg);
+ if (!pids_file)
+ return false;
+
+ /*
+ * write the pids to a socket, have helper in writer's pidns
+ * call movepid for us
+ */
+ if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0) {
+ perror("socketpair");
+ goto out;
+ }
+
+ cpid = fork();
+ if (cpid == -1)
+ goto out;
+
+ if (!cpid) { // child
+ fclose(pids_file);
+ pid_from_ns_wrapper(sock[1], tpid);
+ }
+
+ const char *ptr = buf;
+ while (sscanf(ptr, "%d", &qpid) == 1) {
+ struct ucred cred;
+ char v;
+
+ if (write(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
+ lxcfs_error("Error writing pid to child: %s.\n", strerror(errno));
+ goto out;
+ }
+
+ if (recv_creds(sock[0], &cred, &v)) {
+ if (v == '0') {
+ if (!may_move_pid(tpid, tuid, cred.pid)) {
+ fail = true;
+ break;
+ }
+ if (fprintf(pids_file, "%d", (int) cred.pid) < 0)
+ fail = true;
+ }
+ }
+
+ ptr = strchr(ptr, '\n');
+ if (!ptr)
+ break;
+ ptr++;
+ }
+
+ /* All good, write the value */
+ qpid = -1;
+ if (write(sock[0], &qpid ,sizeof(qpid)) != sizeof(qpid))
+ lxcfs_error("%s\n", "Warning: failed to ask child to exit.");
+
+ if (!fail)
+ answer = true;
+
+out:
+ if (cpid != -1)
+ wait_for_pid(cpid);
+ if (sock[0] != -1) {
+ close(sock[0]);
+ close(sock[1]);
+ }
+ if (pids_file) {
+ if (fclose(pids_file) != 0)
+ answer = false;
+ }
+ return answer;
+}
+
+static bool write_string(const char *fnam, const char *string, int fd)
+{
+ FILE *f;
+ size_t len, ret;
+
+ f = fdopen(fd, "w");
+ if (!f)
+ return false;
+
+ len = strlen(string);
+ ret = fwrite(string, 1, len, f);
+ if (ret != len) {
+ lxcfs_error("%s - Error writing \"%s\" to \"%s\"\n",
+ strerror(errno), string, fnam);
+ fclose(f);
+ return false;
+ }
+
+ if (fclose(f) < 0) {
+ lxcfs_error("%s - Failed to close \"%s\"\n", strerror(errno), fnam);
+ return false;
+ }
+
+ return true;
+}
+
+static bool cgfs_set_value(const char *controller, const char *cgroup,
+ const char *file, const char *value)
+{
+ int ret, fd, cfd;
+ size_t len;
+ char *fnam;
+
+ cfd = get_cgroup_fd(controller);
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions.
+ * . + /cgroup + / + file + \0
+ */
+ len = strlen(cgroup) + strlen(file) + 3;
+ fnam = alloca(len);
+ ret = snprintf(fnam, len, "%s%s/%s", dot_or_empty(cgroup), cgroup, file);
+ if (ret < 0 || (size_t)ret >= len)
+ return false;
+
+ fd = openat(cfd, fnam, O_WRONLY);
+ if (fd < 0)
+ return false;
+
+ return write_string(fnam, value, fd);
+}
+
+int cg_write(const char *path, const char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
+{
+ struct fuse_context *fc = fuse_get_context();
+ char *localbuf = NULL;
+ struct cgfs_files *k = NULL;
+ struct file_info *f = (struct file_info *)fi->fh;
+ bool r;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (f->type != LXC_TYPE_CGFILE) {
+ lxcfs_error("%s\n", "Internal error: directory cache info used in cg_write.");
+ return -EIO;
+ }
+
+ if (offset)
+ return 0;
+
+ localbuf = alloca(size+1);
+ localbuf[size] = '\0';
+ memcpy(localbuf, buf, size);
+
+ if ((k = cgfs_get_key(f->controller, f->cgroup, f->file)) == NULL) {
+ size = -EINVAL;
+ goto out;
+ }
+
+ if (!fc_may_access(fc, f->controller, f->cgroup, f->file, O_WRONLY)) {
+ size = -EACCES;
+ goto out;
+ }
+
+ if (strcmp(f->file, "tasks") == 0 ||
+ strcmp(f->file, "/tasks") == 0 ||
+ strcmp(f->file, "/cgroup.procs") == 0 ||
+ strcmp(f->file, "cgroup.procs") == 0)
+ // special case - we have to translate the pids
+ r = do_write_pids(fc->pid, fc->uid, f->controller, f->cgroup, f->file, localbuf);
+ else
+ r = cgfs_set_value(f->controller, f->cgroup, f->file, localbuf);
+
+ if (!r)
+ size = -EINVAL;
+
+out:
+ free_key(k);
+ return size;
+}
+
+static bool cgfs_iterate_cgroup(const char *controller, const char *cgroup,
+ bool directories, void ***list, size_t typesize,
+ void *(*iterator)(const char *, const char *, const char *))
+{
+ int cfd, fd, ret;
+ size_t len;
+ char *cg;
+ char pathname[MAXPATHLEN];
+ size_t sz = 0, asz = 0;
+ struct dirent *dirent;
+ DIR *dir;
+
+ cfd = get_cgroup_fd(controller);
+ *list = NULL;
+ if (cfd < 0)
+ return false;
+
+ /* Make sure we pass a relative path to *at() family of functions. */
+ len = strlen(cgroup) + 1 /* . */ + 1 /* \0 */;
+ cg = alloca(len);
+ ret = snprintf(cg, len, "%s%s", dot_or_empty(cgroup), cgroup);
+ if (ret < 0 || (size_t)ret >= len) {
+ lxcfs_error("Pathname too long under %s\n", cgroup);
+ return false;
+ }
+
+ fd = openat(cfd, cg, O_DIRECTORY);
+ if (fd < 0)
+ return false;
+
+ dir = fdopendir(fd);
+ if (!dir)
+ return false;
+
+ while ((dirent = readdir(dir))) {
+ struct stat mystat;
+
+ if (!strcmp(dirent->d_name, ".") ||
+ !strcmp(dirent->d_name, ".."))
+ continue;
+
+ ret = snprintf(pathname, MAXPATHLEN, "%s/%s", cg, dirent->d_name);
+ if (ret < 0 || ret >= MAXPATHLEN) {
+ lxcfs_error("Pathname too long under %s\n", cg);
+ continue;
+ }
+
+ ret = fstatat(cfd, pathname, &mystat, AT_SYMLINK_NOFOLLOW);
+ if (ret) {
+ lxcfs_error("Failed to stat %s: %s\n", pathname, strerror(errno));
+ continue;
+ }
+ if ((!directories && !S_ISREG(mystat.st_mode)) ||
+ (directories && !S_ISDIR(mystat.st_mode)))
+ continue;
+
+ if (sz+2 >= asz) {
+ void **tmp;
+ asz += BATCH_SIZE;
+ do {
+ tmp = realloc(*list, asz * typesize);
+ } while (!tmp);
+ *list = tmp;
+ }
+ (*list)[sz] = (*iterator)(controller, cg, dirent->d_name);
+ (*list)[sz+1] = NULL;
+ sz++;
+ }
+ if (closedir(dir) < 0) {
+ lxcfs_error("Failed closedir for %s: %s\n", cgroup, strerror(errno));
+ return false;
+ }
+ return true;
+}
+
+static void *make_key_list_entry(const char *controller, const char *cgroup,
+ const char *dir_entry)
+{
+ struct cgfs_files *entry;
+
+ entry = cgfs_get_key(controller, cgroup, dir_entry);
+ if (!entry)
+ lxcfs_error("Failed to retrieve files under %s:%s\n",
+ controller, cgroup);
+ return entry;
+}
+
+static bool cgfs_list_keys(const char *controller, const char *cgroup,
+ struct cgfs_files ***keys)
+{
+ return cgfs_iterate_cgroup(controller, cgroup, false, (void ***)keys,
+ sizeof(*keys), &make_key_list_entry);
+}
+
+static void *make_children_list_entry(const char *controller,
+ const char *cgroup, const char *dir_entry)
+{
+ return strdup(dir_entry);
+}
+
+static bool cgfs_list_children(const char *controller, const char *cgroup,
+ char ***list)
+{
+ return cgfs_iterate_cgroup(controller, cgroup, true, (void ***)list,
+ sizeof(*list), &make_children_list_entry);
+}
+
+static void free_keys(struct cgfs_files **keys)
+{
+ if (!keys)
+ return;
+
+ for (int i = 0; keys[i]; i++)
+ free_key(keys[i]);
+
+ free_disarm(keys);
+}
+
+int cg_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
+ off_t offset, struct fuse_file_info *fi)
+{
+ struct file_info *d = (struct file_info *)fi->fh;
+ struct cgfs_files **list = NULL;
+ int i, ret;
+ char *nextcg = NULL;
+ struct fuse_context *fc = fuse_get_context();
+ char **clist = NULL;
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (filler(buf, ".", NULL, 0) != 0 || filler(buf, "..", NULL, 0) != 0)
+ return -EIO;
+
+ if (d->type != LXC_TYPE_CGDIR) {
+ lxcfs_error("%s\n", "Internal error: file cache info used in readdir.");
+ return -EIO;
+ }
+ if (!d->cgroup && !d->controller) {
+ /*
+ * ls /var/lib/lxcfs/cgroup - just show list of controllers.
+ * This only works with the legacy hierarchy.
+ */
+ for (struct hierarchy **h = cgroup_ops->hierarchies; h && *h; h++) {
+ if (is_unified_hierarchy(*h))
+ continue;
+
+ if ((*h)->__controllers && filler(buf, (*h)->__controllers, NULL, 0))
+ return -EIO;
+ }
+
+ return 0;
+ }
+
+ if (!cgfs_list_keys(d->controller, d->cgroup, &list)) {
+ // not a valid cgroup
+ ret = -EINVAL;
+ goto out;
+ }
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (!caller_is_in_ancestor(initpid, d->controller, d->cgroup, &nextcg)) {
+ if (nextcg) {
+ ret = filler(buf, nextcg, NULL, 0);
+ free(nextcg);
+ if (ret != 0) {
+ ret = -EIO;
+ goto out;
+ }
+ }
+ ret = 0;
+ goto out;
+ }
+
+ for (i = 0; list && list[i]; i++) {
+ if (filler(buf, list[i]->name, NULL, 0) != 0) {
+ ret = -EIO;
+ goto out;
+ }
+ }
+
+ // now get the list of child cgroups
+
+ if (!cgfs_list_children(d->controller, d->cgroup, &clist)) {
+ ret = 0;
+ goto out;
+ }
+ if (clist) {
+ for (i = 0; clist[i]; i++) {
+ if (filler(buf, clist[i], NULL, 0) != 0) {
+ ret = -EIO;
+ goto out;
+ }
+ }
+ }
+ ret = 0;
+
+out:
+ free_keys(list);
+ if (clist) {
+ for (i = 0; clist[i]; i++)
+ free(clist[i]);
+ free(clist);
+ }
+ return ret;
+}
+
+int cg_access(const char *path, int mode)
+{
+ int ret;
+ const char *cgroup;
+ char *path1, *path2, *controller;
+ char *last = NULL, *cgdir = NULL;
+ struct cgfs_files *k = NULL;
+ struct fuse_context *fc = fuse_get_context();
+
+ if (!fc || !cgroup_ops || pure_unified_layout(cgroup_ops))
+ return -EIO;
+
+ if (strcmp(path, "/cgroup") == 0)
+ return 0;
+
+ controller = pick_controller_from_path(fc, path);
+ if (!controller)
+ return -errno;
+ cgroup = find_cgroup_in_path(path);
+ if (!cgroup) {
+ // access("/sys/fs/cgroup/systemd", mode) - rx allowed, w not
+ if ((mode & W_OK) == 0)
+ return 0;
+ return -EACCES;
+ }
+
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last) {
+ path1 = "/";
+ path2 = cgdir;
+ } else {
+ path1 = cgdir;
+ path2 = last;
+ }
+
+ k = cgfs_get_key(controller, path1, path2);
+ if (!k) {
+ if ((mode & W_OK) == 0)
+ ret = 0;
+ else
+ ret = -EACCES;
+ goto out;
+ }
+ free_key(k);
+
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 1 || is_shared_pidns(initpid))
+ initpid = fc->pid;
+ if (!caller_may_see_dir(initpid, controller, path1)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ if (!fc_may_access(fc, controller, path1, path2, mode)) {
+ ret = -EACCES;
+ goto out;
+ }
+
+ ret = 0;
+
+out:
+ free(cgdir);
+ return ret;
+}
projects / mirror_lxcfs.git / commitdiff