/* lxcfs
*
- * Copyright © 2014,2015 Canonical, Inc
+ * Copyright © 2014-2016 Canonical, Inc
* Author: Serge Hallyn <serge.hallyn@ubuntu.com>
*
* See COPYING file for details.
*/
-/*
- * TODO XXX
- * sanitize paths for '..', cgmanager's not doing that for us any more
- * does fuse help us?
- * Surely there are more paths we'll need to sanitize - look back through
- * cgmanager's sources.
- */
-
#define FUSE_USE_VERSION 26
#include <stdio.h>
#include <stdlib.h>
#include <libgen.h>
#include <sched.h>
+#include <pthread.h>
#include <linux/sched.h>
#include <sys/socket.h>
#include <sys/mount.h>
+#include <sys/epoll.h>
#include <wait.h>
#ifdef FORTRAVIS
#define BUF_RESERVE_SIZE 256
/*
- * 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
+ * A table caching which pid is init for a pid namespace.
+ * When looking up which pid is init for $qpid, we first
+ * 1. Stat /proc/$qpid/ns/pid.
+ * 2. Check whether the ino_t is in our store.
+ * a. if not, fork a child in qpid's ns to send us
+ * ucred.pid = 1, and read the initpid. Cache
+ * initpid and creation time for /proc/initpid
+ * in a new store entry.
+ * b. if so, verify that /proc/initpid still matches
+ * what we have saved. If not, clear the store
+ * entry and go back to a. If so, return the
+ * cached initpid.
*/
-static void must_strcat_pid(char **src, size_t *sz, size_t *asz, pid_t pid)
+struct pidns_init_store {
+ ino_t ino; // inode number for /proc/$pid/ns/pid
+ pid_t initpid; // the pid of nit in that ns
+ long int ctime; // the time at which /proc/$initpid was created
+ struct pidns_init_store *next;
+ long int lastcheck;
+};
+
+/* lol - look at how they are allocated in the kernel */
+#define PIDNS_HASH_SIZE 4096
+#define HASH(x) ((x) % PIDNS_HASH_SIZE)
+
+struct pidns_init_store *pidns_hash_table[PIDNS_HASH_SIZE];
+static pthread_mutex_t pidns_store_mutex = PTHREAD_MUTEX_INITIALIZER;
+static void lock_mutex(pthread_mutex_t *l)
{
- char *d = *src;
- char tmp[30];
+ int ret;
- sprintf(tmp, "%d\n", (int)pid);
+ if ((ret = pthread_mutex_lock(l)) != 0) {
+ fprintf(stderr, "pthread_mutex_lock returned:%d %s\n", ret, strerror(ret));
+ exit(1);
+ }
+}
- if (!d) {
- do {
- d = malloc(BUF_RESERVE_SIZE);
- } while (!d);
- *src = d;
- *asz = BUF_RESERVE_SIZE;
- } else if (strlen(tmp) + sz + 1 >= asz) {
- do {
- d = realloc(d, *asz + BUF_RESERVE_SIZE);
- } while (!d);
- *src = d;
- *asz += BUF_RESERVE_SIZE;
+static void unlock_mutex(pthread_mutex_t *l)
+{
+ int ret;
+
+ if ((ret = pthread_mutex_unlock(l)) != 0) {
+ fprintf(stderr, "pthread_mutex_unlock returned:%d %s\n", ret, strerror(ret));
+ exit(1);
+ }
+}
+
+static void store_lock(void)
+{
+ lock_mutex(&pidns_store_mutex);
+}
+
+static void store_unlock(void)
+{
+ unlock_mutex(&pidns_store_mutex);
+}
+
+/* Must be called under store_lock */
+static bool initpid_still_valid(struct pidns_init_store *e, struct stat *nsfdsb)
+{
+ struct stat initsb;
+ char fnam[100];
+
+ snprintf(fnam, 100, "/proc/%d", e->initpid);
+ if (stat(fnam, &initsb) < 0)
+ return false;
+#if DEBUG
+ fprintf(stderr, "comparing ctime %ld %ld for pid %d\n",
+ e->ctime, initsb.st_ctime, e->initpid);
+#endif
+ if (e->ctime != initsb.st_ctime)
+ return false;
+ return true;
+}
+
+/* Must be called under store_lock */
+static void remove_initpid(struct pidns_init_store *e)
+{
+ struct pidns_init_store *tmp;
+ int h;
+
+#if DEBUG
+ fprintf(stderr, "remove_initpid: removing entry for %d\n", e->initpid);
+#endif
+ h = HASH(e->ino);
+ if (pidns_hash_table[h] == e) {
+ pidns_hash_table[h] = e->next;
+ free(e);
+ return;
+ }
+
+ tmp = pidns_hash_table[h];
+ while (tmp) {
+ if (tmp->next == e) {
+ tmp->next = e->next;
+ free(e);
+ return;
+ }
+ tmp = tmp->next;
+ }
+}
+
+#define PURGE_SECS 5
+/* Must be called under store_lock */
+static void prune_initpid_store(void)
+{
+ static long int last_prune = 0;
+ struct pidns_init_store *e, *prev, *delme;
+ long int now, threshold;
+ int i;
+
+ if (!last_prune) {
+ last_prune = time(NULL);
+ return;
+ }
+ now = time(NULL);
+ if (now < last_prune + PURGE_SECS)
+ return;
+#if DEBUG
+ fprintf(stderr, "pruning\n");
+#endif
+ last_prune = now;
+ threshold = now - 2 * PURGE_SECS;
+
+ for (i = 0; i < PIDNS_HASH_SIZE; i++) {
+ for (prev = NULL, e = pidns_hash_table[i]; e; ) {
+ if (e->lastcheck < threshold) {
+#if DEBUG
+ fprintf(stderr, "Removing cached entry for %d\n", e->initpid);
+#endif
+ delme = e;
+ if (prev)
+ prev->next = e->next;
+ else
+ pidns_hash_table[i] = e->next;
+ e = e->next;
+ free(delme);
+ } else {
+ prev = e;
+ e = e->next;
+ }
+ }
}
- memcpy(d+*sz, tmp, strlen(tmp));
- *sz += strlen(tmp);
- d[*sz] = '\0';
+}
+
+/* Must be called under store_lock */
+static void save_initpid(struct stat *sb, pid_t pid)
+{
+ struct pidns_init_store *e;
+ char fpath[100];
+ struct stat procsb;
+ int h;
+
+#if DEBUG
+ fprintf(stderr, "save_initpid: adding entry for %d\n", pid);
+#endif
+ snprintf(fpath, 100, "/proc/%d", pid);
+ if (stat(fpath, &procsb) < 0)
+ return;
+ do {
+ e = malloc(sizeof(*e));
+ } while (!e);
+ e->ino = sb->st_ino;
+ e->initpid = pid;
+ e->ctime = procsb.st_ctime;
+ h = HASH(e->ino);
+ e->next = pidns_hash_table[h];
+ e->lastcheck = time(NULL);
+ pidns_hash_table[h] = e;
+}
+
+/*
+ * Given the stat(2) info for a nsfd pid inode, lookup the init_pid_store
+ * entry for the inode number and creation time. Verify that the init pid
+ * is still valid. If not, remove it. Return the entry if valid, NULL
+ * otherwise.
+ * Must be called under store_lock
+ */
+static struct pidns_init_store *lookup_verify_initpid(struct stat *sb)
+{
+ int h = HASH(sb->st_ino);
+ struct pidns_init_store *e = pidns_hash_table[h];
+
+ while (e) {
+ if (e->ino == sb->st_ino) {
+ if (initpid_still_valid(e, sb)) {
+ e->lastcheck = time(NULL);
+ return e;
+ }
+ remove_initpid(e);
+ return NULL;
+ }
+ e = e->next;
+ }
+
+ return NULL;
+}
+
+#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);
+
+/*
+ * fork 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
+ */
+static void write_task_init_pid_exit(int sock, pid_t target)
+{
+ struct ucred cred;
+ char fnam[100];
+ pid_t pid;
+ char v;
+ int fd, ret;
+
+ 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 = fork();
+ if (pid < 0)
+ _exit(1);
+ if (pid != 0) {
+ if (!wait_for_pid(pid))
+ _exit(1);
+ _exit(0);
+ }
+
+ /* 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)
+ _exit(1);
+ _exit(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;
+}
+
+static 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) {
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)
+{
+ char tmp[30];
+
+ int tmplen = sprintf(tmp, "%d\n", (int)pid);
+
+ if (!*src || tmplen + *sz + 1 >= *asz) {
+ char *tmp;
+ do {
+ tmp = realloc(*src, *asz + BUF_RESERVE_SIZE);
+ } while (!tmp);
+ *src = tmp;
+ *asz += BUF_RESERVE_SIZE;
+ }
+ memcpy((*src) +*sz , tmp, tmplen);
+ *sz += tmplen;
+ (*src)[*sz] = '\0';
+}
+
/*
* 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
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;
struct cgfs_files *k = NULL;
bool ret = false;
- if (!file)
- file = "tasks";
-
- if (*file == '/')
- file++;
-
k = cgfs_get_key(contrl, cg, file);
if (!k)
return false;
static void prune_init_slice(char *cg)
{
char *point;
- point = cg + strlen(cg) - strlen(INITSCOPE);
- if (point < cg)
- return;
+ 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';
}
/*
- * If caller is in /a/b/c/d, he may only act on things under cg=/a/b/c/d.
- * If caller is in /a, he may act on /a/b, but not on /b.
+ * 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)
{
- char fnam[PROCLEN];
- FILE *f;
bool answer = false;
- char *line = NULL;
- size_t len = 0;
- int ret;
+ char *c2 = get_pid_cgroup(pid, contrl);
+ char *linecmp;
- ret = snprintf(fnam, PROCLEN, "/proc/%d/cgroup", pid);
- if (ret < 0 || ret >= PROCLEN)
- return false;
- if (!(f = fopen(fnam, "r")))
+ if (!c2)
return false;
+ prune_init_slice(c2);
- while (getline(&line, &len, f) != -1) {
- char *c1, *c2, *linecmp;
- if (!line[0])
- continue;
- c1 = strchr(line, ':');
- if (!c1)
- goto out;
- c1++;
- c2 = strchr(c1, ':');
- if (!c2)
- goto out;
- *c2 = '\0';
- if (strcmp(c1, contrl) != 0)
- continue;
- c2++;
- stripnewline(c2);
- prune_init_slice(c2);
- /*
- * callers pass in '/' for root cgroup, otherwise they pass
- * in a cgroup without leading '/'
- */
- linecmp = *cg == '/' ? c2 : c2+1;
- if (strncmp(linecmp, cg, strlen(linecmp)) != 0) {
- if (nextcg)
- *nextcg = get_next_cgroup_dir(linecmp, cg);
- goto out;
+ /*
+ * callers pass in '/' for root cgroup, otherwise they pass
+ * in a cgroup without leading '/'
+ */
+ linecmp = *cg == '/' ? c2 : 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)
+ 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:
- fclose(f);
- free(line);
+ free(c2);
return answer;
}
}
/*
- * dir should be freed, file not
- */
-static void get_cgdir_and_path(const char *cg, char **dir, char **file)
+ * 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);
- *file = strrchr(cg, '/');
- if (!*file) {
- *file = NULL;
+ *last = strrchr(cg, '/');
+ if (!*last) {
+ *last = NULL;
return;
}
p = strrchr(*dir, '/');
struct timespec now;
struct fuse_context *fc = fuse_get_context();
char * cgdir = NULL;
- char *fpath = NULL, *path1, *path2;
+ char *last = NULL, *path1, *path2;
struct cgfs_files *k = NULL;
const char *cgroup;
const char *controller = NULL;
return 0;
}
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
+ get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!fpath) {
+ if (!last) {
path1 = "/";
path2 = cgdir;
} else {
path1 = cgdir;
- path2 = fpath;
+ path2 = last;
}
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ 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 fpath is a child
- * cgroup, or cgdir if fpath is a file */
+ * 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_is_in_ancestor(fc->pid, controller, cgroup, NULL)) {
+ 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;
// 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, "tasks");
+ k = cgfs_get_key(controller, cgroup, NULL);
if (!k) {
sb->st_uid = sb->st_gid = 0;
} else {
sb->st_gid = k->gid;
sb->st_size = 0;
free_key(k);
- if (!caller_is_in_ancestor(fc->pid, controller, path1, NULL)) {
+ if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
ret = -ENOENT;
goto out;
}
}
}
- if (cgroup && !fc_may_access(fc, controller, cgroup, NULL, O_RDONLY)) {
- return -EACCES;
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ 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 */
goto out;
}
- if (!caller_is_in_ancestor(fc->pid, d->controller, d->cgroup, &nextcg)) {
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ if (!caller_is_in_ancestor(initpid, d->controller, d->cgroup, &nextcg)) {
if (nextcg) {
int ret;
ret = filler(buf, nextcg, NULL, 0);
static int cg_open(const char *path, struct fuse_file_info *fi)
{
const char *cgroup;
- char *fpath = NULL, *path1, *path2, * cgdir = NULL, *controller;
+ 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();
if (!cgroup)
return -EINVAL;
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
- if (!fpath) {
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last) {
path1 = "/";
path2 = cgdir;
} else {
path1 = cgdir;
- path2 = fpath;
+ path2 = last;
}
k = cgfs_get_key(controller, path1, path2);
}
free_key(k);
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ 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)) {
// should never get here
ret = -EACCES;
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) {
+ fprintf(stderr, "Failed to create epoll socket: %m\n");
+ return false;
+ }
+
+ ev.events = POLLIN_SET;
+ ev.data.fd = sock;
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
+ fprintf(stderr, "Failed adding socket to epoll: %m\n");
+ 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)
{
- struct timeval tv;
- fd_set rfds;
-
- FD_ZERO(&rfds);
- FD_SET(sockfd, &rfds);
- tv.tv_sec = 2;
- tv.tv_usec = 0;
-
- if (select(sockfd+1, &rfds, NULL, NULL, &tv) <= 0)
+ 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 };
char buf[1];
int ret;
int optval = 1;
- struct timeval tv;
- fd_set rfds;
*v = '1';
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
- FD_ZERO(&rfds);
- FD_SET(sock, &rfds);
- tv.tv_sec = 2;
- tv.tv_usec = 0;
- if (select(sock+1, &rfds, NULL, NULL, &tv) <= 0) {
- fprintf(stderr, "Failed to select for scm_cred: %s\n",
+ if (!wait_for_sock(sock, 2)) {
+ fprintf(stderr, "Timed out waiting for scm_cred: %s\n",
strerror(errno));
return false;
}
int newnsfd = -1, ret, cpipe[2];
char fnam[100];
pid_t cpid;
- struct timeval tv;
- fd_set s;
char v;
ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
if (pipe(cpipe) < 0)
_exit(1);
-loop:
cpid = fork();
if (cpid < 0)
_exit(1);
}
close(cpipe[1]);
pid_to_ns(sock, tpid);
+ _exit(1); // not reached
}
// give the child 1 second to be done forking and
- // write it's ack
- FD_ZERO(&s);
- FD_SET(cpipe[0], &s);
- tv.tv_sec = 1;
- tv.tv_usec = 0;
- ret = select(cpipe[0]+1, &s, NULL, NULL, &tv);
- if (ret <= 0)
- goto again;
+ // write its ack
+ if (!wait_for_sock(cpipe[0], 1))
+ _exit(1);
ret = read(cpipe[0], &v, 1);
- if (ret != sizeof(char) || v != '1') {
- goto again;
- }
+ if (ret != sizeof(char) || v != '1')
+ _exit(1);
if (!wait_for_pid(cpid))
_exit(1);
_exit(0);
-
-again:
- kill(cpid, SIGKILL);
- wait_for_pid(cpid);
- goto loop;
}
/*
bool answer = false;
char v = '0';
struct ucred cred;
- struct timeval tv;
size_t sz = 0, asz = 0;
- fd_set s;
if (!cgfs_get_value(contrl, cg, file, &tmpdata))
return false;
if (cpid == -1)
goto out;
- if (!cpid) // child
+ if (!cpid) // child - exits when done
pid_to_ns_wrapper(sock[1], tpid);
char *ptr = tmpdata;
goto out;
// read converted results
- FD_ZERO(&s);
- FD_SET(sock[0], &s);
- tv.tv_sec = 2;
- tv.tv_usec = 0;
- ret = select(sock[0]+1, &s, NULL, NULL, &tv);
- if (ret <= 0) {
- fprintf(stderr, "%s: select error waiting for pid from child: %s\n",
+ if (!wait_for_sock(sock[0], 2)) {
+ fprintf(stderr, "%s: timed out waiting for pid from child: %s\n",
__func__, strerror(errno));
goto out;
}
pid_t vpid;
struct ucred cred;
char v;
- struct timeval tv;
- fd_set s;
int ret;
cred.uid = 0;
cred.gid = 0;
while (1) {
- FD_ZERO(&s);
- FD_SET(sock, &s);
- tv.tv_sec = 2;
- tv.tv_usec = 0;
- ret = select(sock+1, &s, NULL, NULL, &tv);
- if (ret <= 0) {
- fprintf(stderr, "%s: bad select before read from parent: %s\n",
- __func__, strerror(errno));
+ if (!wait_for_sock(sock, 2)) {
+ fprintf(stderr, "%s: timeout reading from parent\n", __func__);
_exit(1);
}
if ((ret = read(sock, &vpid, sizeof(pid_t))) != sizeof(pid_t)) {
int newnsfd = -1, ret, cpipe[2];
char fnam[100];
pid_t cpid;
- fd_set s;
- struct timeval tv;
char v;
ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", tpid);
}
// give the child 1 second to be done forking and
- // write it's ack
- FD_ZERO(&s);
- FD_SET(cpipe[0], &s);
- tv.tv_sec = 1;
- tv.tv_usec = 0;
- ret = select(cpipe[0]+1, &s, NULL, NULL, &tv);
- if (ret <= 0)
+ // write its ack
+ if (!wait_for_sock(cpipe[0], 1))
goto again;
ret = read(cpipe[0], &v, 1);
if (ret != sizeof(char) || v != '1') {
goto loop;
}
-static bool do_write_pids(pid_t tpid, const char *contrl, const char *cg, const char *file, const char *buf)
+/*
+ * 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) {
+ fprintf(stderr, "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) {
+ fprintf(stderr, "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) {
+ fprintf(stderr, "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;
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;
}
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, f->controller, f->cgroup, f->file, localbuf);
+ 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);
int cg_chown(const char *path, uid_t uid, gid_t gid)
{
struct fuse_context *fc = fuse_get_context();
- char *cgdir = NULL, *fpath = NULL, *path1, *path2, *controller;
+ char *cgdir = NULL, *last = NULL, *path1, *path2, *controller;
struct cgfs_files *k = NULL;
const char *cgroup;
int ret;
/* this is just /cgroup/controller */
return -EINVAL;
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
+ get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!fpath) {
+ if (!last) {
path1 = "/";
path2 = cgdir;
} else {
path1 = cgdir;
- path2 = fpath;
+ path2 = last;
}
if (is_child_cgroup(controller, path1, path2)) {
int cg_chmod(const char *path, mode_t mode)
{
struct fuse_context *fc = fuse_get_context();
- char * cgdir = NULL, *fpath = NULL, *path1, *path2, *controller;
+ char * cgdir = NULL, *last = NULL, *path1, *path2, *controller;
struct cgfs_files *k = NULL;
const char *cgroup;
int ret;
/* this is just /cgroup/controller */
return -EINVAL;
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
+ get_cgdir_and_path(cgroup, &cgdir, &last);
- if (!fpath) {
+ if (!last) {
path1 = "/";
path2 = cgdir;
} else {
path1 = cgdir;
- path2 = fpath;
+ path2 = last;
}
if (is_child_cgroup(controller, path1, path2)) {
int cg_mkdir(const char *path, mode_t mode)
{
struct fuse_context *fc = fuse_get_context();
- char *fpath = NULL, *path1, *cgdir = NULL, *controller;
+ char *last = NULL, *path1, *cgdir = NULL, *controller, *next = NULL;
const char *cgroup;
int ret;
if (!cgroup)
return -EINVAL;
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
- if (!fpath)
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last)
path1 = "/";
else
path1 = cgdir;
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ 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 = -ENOENT;
+ goto out;
+ }
+
if (!fc_may_access(fc, controller, path1, NULL, O_RDWR)) {
ret = -EACCES;
goto out;
}
- if (!caller_is_in_ancestor(fc->pid, controller, path1, NULL)) {
+ if (!caller_is_in_ancestor(initpid, controller, path1, NULL)) {
ret = -EACCES;
goto out;
}
ret = cgfs_create(controller, cgroup, fc->uid, fc->gid);
- printf("cgfs_create returned %d for %s %s\n", ret, controller, cgroup);
out:
free(cgdir);
+ free(next);
return ret;
}
static int cg_rmdir(const char *path)
{
struct fuse_context *fc = fuse_get_context();
- char *fpath = NULL, *cgdir = NULL, *controller;
+ char *last = NULL, *cgdir = NULL, *controller, *next = NULL;
const char *cgroup;
int ret;
if (!cgroup)
return -EINVAL;
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
- if (!fpath) {
+ get_cgdir_and_path(cgroup, &cgdir, &last);
+ if (!last) {
ret = -EINVAL;
goto out;
}
- fprintf(stderr, "rmdir: verifying access to %s:%s (req path %s)\n",
- controller, cgdir, path);
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ if (!caller_is_in_ancestor(initpid, controller, cgroup, &next)) {
+ if (!last || 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(fc->pid, controller, cgroup, NULL)) {
+ if (!caller_is_in_ancestor(initpid, controller, cgroup, NULL)) {
ret = -EACCES;
goto out;
}
out:
free(cgdir);
+ free(next);
return ret;
}
rv = 0;
goto err;
}
- if (l < cache_size) {
- cache += l;
- cache_size -= l;
- total_len += l;
- } else {
- cache += cache_size;
- total_len += cache_size;
- cache_size = 0;
- break;
- }
+ cache += l;
+ cache_size -= l;
+ total_len += l;
}
d->size = total_len;
struct file_info *d = (struct file_info *)fi->fh;
char *cg;
char *memusage_str = NULL, *memstat_str = NULL,
- *memswlimit_str = NULL, *memswusage_str = NULL;
+ *memswlimit_str = NULL, *memswusage_str = NULL,
+ *memswlimit_default_str = NULL, *memswusage_default_str = NULL;
unsigned long memlimit = 0, memusage = 0, memswlimit = 0, memswusage = 0,
cached = 0, hosttotal = 0;
char *line = NULL;
return total_len;
}
- cg = get_pid_cgroup(fc->pid, "memory");
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ cg = get_pid_cgroup(initpid, "memory");
if (!cg)
return read_file("/proc/meminfo", buf, size, d);
if(cgfs_get_value("memory", cg, "memory.memsw.limit_in_bytes", &memswlimit_str) &&
cgfs_get_value("memory", cg, "memory.memsw.usage_in_bytes", &memswusage_str))
{
+ /* If swapaccounting is turned on, then default value is assumed to be that of cgroup / */
+ if (!cgfs_get_value("memory", "/", "memory.memsw.limit_in_bytes", &memswlimit_default_str))
+ goto err;
+ if (!cgfs_get_value("memory", "/", "memory.memsw.usage_in_bytes", &memswusage_default_str))
+ goto err;
+
memswlimit = strtoul(memswlimit_str, NULL, 10);
memswusage = strtoul(memswusage_str, NULL, 10);
- memswlimit /= 1024;
- memswusage /= 1024;
+
+ if (!strcmp(memswlimit_str, memswlimit_default_str))
+ memswlimit = 0;
+ if (!strcmp(memswusage_str, memswusage_default_str))
+ memswusage = 0;
+
+ memswlimit = memswlimit / 1024;
+ memswusage = memswusage / 1024;
}
-
+
memusage = strtoul(memusage_str, NULL, 10);
memlimit /= 1024;
memusage /= 1024;
+
get_mem_cached(memstat_str, &cached);
f = fopen("/proc/meminfo", "r");
free(memswlimit_str);
free(memswusage_str);
free(memstat_str);
+ free(memswlimit_default_str);
+ free(memswusage_default_str);
return rv;
}
return total_len;
}
- cg = get_pid_cgroup(fc->pid, "cpuset");
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ cg = get_pid_cgroup(initpid, "cpuset");
if (!cg)
return read_file("proc/cpuinfo", buf, size, d);
rv = 0;
goto err;
}
- if (l < cache_size){
- cache += l;
- cache_size -= l;
- total_len += l;
- }else{
- cache += cache_size;
- total_len += cache_size;
- cache_size = 0;
- break;
- }
+ cache += l;
+ cache_size -= l;
+ total_len += l;
}
continue;
}
rv = 0;
goto err;
}
- if (l < cache_size) {
- cache += l;
- cache_size -= l;
- total_len += l;
- } else {
- cache += cache_size;
- total_len += cache_size;
- cache_size = 0;
- break;
- }
+ cache += l;
+ cache_size -= l;
+ total_len += l;
}
}
return total_len;
}
- cg = get_pid_cgroup(fc->pid, "cpuset");
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ cg = get_pid_cgroup(initpid, "cpuset");
if (!cg)
return read_file("/proc/stat", buf, size, d);
rv = 0;
goto err;
}
- if (l < cache_size) {
- cache += l;
- cache_size -= l;
- total_len += l;
- continue;
- } else {
- //no more space, break it
- cache += cache_size;
- total_len += cache_size;
- cache_size = 0;
- break;
- }
+ cache += l;
+ cache_size -= l;
+ total_len += l;
+ continue;
}
if (sscanf(cpu_char, "%d", &cpu) != 1)
return rv;
}
-/*
- * How to guess what to present for uptime?
- * One thing we could do would be to take the date on the caller's
- * memory.usage_in_bytes file, which should equal the time of creation
- * of his cgroup. However, a task could be in a sub-cgroup of the
- * container. The same problem exists if we try to look at the ages
- * of processes in the caller's cgroup.
- *
- * So we'll fork a task that will enter the caller's pidns, mount a
- * fresh procfs, get the age of /proc/1, and pass that back over a pipe.
- *
- * For the second uptime #, we'll do as Stéphane had done, just copy
- * the number from /proc/uptime. Not sure how to best emulate 'idle'
- * time. Maybe someone can come up with a good algorithm and submit a
- * patch. Maybe something based on cpushare info?
- */
-
-/* return age of the reaper for $pid, taken from ctime of its procdir */
-static long int get_pid1_time(pid_t pid)
+static long int getreaperage(pid_t pid)
{
char fnam[100];
- int fd, cpipe[2], ret;
struct stat sb;
- pid_t cpid;
- struct timeval tv;
- fd_set s;
- char v;
-
- if (unshare(CLONE_NEWNS))
- return 0;
-
- if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL)) {
- perror("rslave mount failed");
- return 0;
- }
-
- ret = snprintf(fnam, sizeof(fnam), "/proc/%d/ns/pid", pid);
- if (ret < 0 || ret >= sizeof(fnam))
- return 0;
+ int ret;
+ pid_t qpid;
- fd = open(fnam, O_RDONLY);
- if (fd < 0) {
- perror("get_pid1_time open of ns/pid");
+ qpid = lookup_initpid_in_store(pid);
+ if (qpid <= 0)
return 0;
- }
- if (setns(fd, 0)) {
- perror("get_pid1_time setns 1");
- close(fd);
- return 0;
- }
- close(fd);
-
- if (pipe(cpipe) < 0)
- exit(1);
-loop:
- cpid = fork();
- if (cpid < 0)
+ ret = snprintf(fnam, 100, "/proc/%d", qpid);
+ if (ret < 0 || ret >= 100)
return 0;
- if (!cpid) {
- char b = '1';
- close(cpipe[0]);
- if (write(cpipe[1], &b, sizeof(char)) < 0) {
- fprintf(stderr, "%s (child): erorr on write: %s\n",
- __func__, strerror(errno));
- }
- close(cpipe[1]);
- umount2("/proc", MNT_DETACH);
- if (mount("proc", "/proc", "proc", 0, NULL)) {
- perror("get_pid1_time mount");
- return 0;
- }
- ret = lstat("/proc/1", &sb);
- if (ret) {
- perror("get_pid1_time lstat");
- return 0;
- }
- return time(NULL) - sb.st_ctime;
- }
-
- // give the child 1 second to be done forking and
- // write it's ack
- FD_ZERO(&s);
- FD_SET(cpipe[0], &s);
- tv.tv_sec = 1;
- tv.tv_usec = 0;
- ret = select(cpipe[0]+1, &s, NULL, NULL, &tv);
- if (ret <= 0)
- goto again;
- ret = read(cpipe[0], &v, 1);
- if (ret != sizeof(char) || v != '1') {
- goto again;
- }
-
- wait_for_pid(cpid);
- _exit(0);
-
-again:
- kill(cpid, SIGKILL);
- wait_for_pid(cpid);
- goto loop;
-}
-
-static long int getreaperage(pid_t qpid)
-{
- int pid, mypipe[2], ret;
- struct timeval tv;
- fd_set s;
- long int mtime, answer = 0;
-
- if (pipe(mypipe)) {
+ if (lstat(fnam, &sb) < 0)
return 0;
- }
-
- pid = fork();
-
- if (!pid) { // child
- mtime = get_pid1_time(qpid);
- if (write(mypipe[1], &mtime, sizeof(mtime)) != sizeof(mtime))
- fprintf(stderr, "Warning: bad write from getreaperage\n");
- _exit(0);
- }
-
- close(mypipe[1]);
- FD_ZERO(&s);
- FD_SET(mypipe[0], &s);
- tv.tv_sec = 1;
- tv.tv_usec = 0;
- ret = select(mypipe[0]+1, &s, NULL, NULL, &tv);
- if (ret <= 0) {
- perror("select");
- goto out;
- }
- if (!ret) {
- fprintf(stderr, "timed out\n");
- goto out;
- }
- if (read(mypipe[0], &mtime, sizeof(mtime)) != sizeof(mtime)) {
- perror("read");
- goto out;
- }
- answer = mtime;
-
-out:
- wait_for_pid(pid);
- close(mypipe[0]);
- return answer;
-}
-
-/*
- * fork 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
- */
-void write_task_init_pid_exit(int sock, pid_t target)
-{
- struct ucred cred;
- char fnam[100];
- pid_t pid;
- char v;
- int fd, ret;
-
- 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("get_pid1_time open of ns/pid");
- exit(1);
- }
- if (setns(fd, 0)) {
- perror("get_pid1_time setns 1");
- close(fd);
- exit(1);
- }
- pid = fork();
- if (pid < 0)
- exit(1);
- if (pid != 0) {
- wait_for_pid(pid);
- exit(0);
- }
-
- /* we are the child */
- cred.uid = 0;
- cred.gid = 0;
- cred.pid = 1;
- v = '1';
- send_creds(sock, &cred, v, true);
- exit(0);
-}
-
-static pid_t get_task_reaper_pid(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);
- }
-
- if (!recv_creds(sock[1], &cred, &v))
- goto out;
- ret = cred.pid;
-
-out:
- close(sock[0]);
- close(sock[1]);
- return ret;
+ return time(NULL) - sb.st_ctime;
}
static unsigned long get_reaper_busy(pid_t task)
{
- pid_t init = get_task_reaper_pid(task);
+ pid_t initpid = lookup_initpid_in_store(task);
char *cgroup = NULL, *usage_str = NULL;
unsigned long usage = 0;
- if (init == -1)
+ if (initpid <= 0)
return 0;
- cgroup = get_pid_cgroup(task, "cpuacct");
+ cgroup = get_pid_cgroup(initpid, "cpuacct");
if (!cgroup)
goto out;
if (!cgfs_get_value("cpuacct", cgroup, "cpuacct.usage", &usage_str))
goto out;
usage = strtoul(usage_str, NULL, 10);
- usage /= 100000000;
+ usage /= 1000000000;
out:
free(cgroup);
{
struct fuse_context *fc = fuse_get_context();
struct file_info *d = (struct file_info *)fi->fh;
- long int reaperage = getreaperage(fc->pid);;
+ long int reaperage = getreaperage(fc->pid);
unsigned long int busytime = get_reaper_busy(fc->pid), idletime;
char *cache = d->buf;
size_t total_len = 0;
return total_len;
}
- cg = get_pid_cgroup(fc->pid, "blkio");
+ pid_t initpid = lookup_initpid_in_store(fc->pid);
+ if (initpid <= 0)
+ initpid = fc->pid;
+ cg = get_pid_cgroup(initpid, "blkio");
if (!cg)
return read_file("/proc/diskstats", buf, size, d);
projects / mirror_lxcfs.git / blobdiff