#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/param.h>
#include <sys/socket.h>
#include <sys/syscall.h>
+#include <sys/vfs.h>
#include "bindings.h"
#include "config.h" // for VERSION
extern int pivot_root(const char * new_root, const char * put_old);
#endif
-#ifdef DEBUG
-#define lxcfs_debug(format, ...) \
- do { \
- fprintf(stderr, "%s: %d: %s: " format, __FILE__, __LINE__, \
- __func__, __VA_ARGS__); \
- } while (false)
-#else
-#define lxcfs_debug(format, ...)
-#endif /* DEBUG */
-
enum {
LXC_TYPE_CGDIR,
LXC_TYPE_CGFILE,
int ret;
if ((ret = pthread_mutex_lock(l)) != 0) {
- fprintf(stderr, "pthread_mutex_lock returned:%d %s\n", ret, strerror(ret));
+ lxcfs_error("returned:%d %s\n", ret, strerror(ret));
exit(1);
}
}
int ret;
if ((ret = pthread_mutex_unlock(l)) != 0) {
- fprintf(stderr, "pthread_mutex_unlock returned:%d %s\n", ret, strerror(ret));
+ lxcfs_error("returned:%d %s\n", ret, strerror(ret));
exit(1);
}
}
len = strlen(string);
ret = fwrite(string, 1, len, f);
if (ret != len) {
- fprintf(stderr, "Error writing to file: %s\n", strerror(errno));
+ lxcfs_error("Error writing to file: %s\n", strerror(errno));
fclose(f);
return false;
}
if (fclose(f) < 0) {
- fprintf(stderr, "Error writing to file: %s\n", strerror(errno));
+ lxcfs_error("Error writing to file: %s\n", strerror(errno));
return false;
}
return true;
n *= ALLOC_NUM;
char **tmp = realloc(hierarchies, n * sizeof(char *));
if (!tmp) {
- fprintf(stderr, "Out of memory\n");
+ lxcfs_error("%s\n", strerror(errno));
exit(1);
}
hierarchies = tmp;
fprintf(stderr, "hierarchies:\n");
for (i = 0; i < num_hierarchies; i++) {
if (hierarchies[i])
- fprintf(stderr, " %d: %s\n", i, hierarchies[i]);
+ fprintf(stderr, " %2d: fd: %3d: %s\n", i,
+ fd_hierarchies[i], hierarchies[i]);
}
}
len = strlen(dirname);
if (len >= MAXPATHLEN) {
- fprintf(stderr, "chown_all_cgroup_files: pathname too long: %s\n", dirname);
+ lxcfs_error("Pathname too long: %s\n", dirname);
return;
}
d = fdopendir(fd1);
if (!d) {
- fprintf(stderr, "chown_all_cgroup_files: failed to open %s\n", dirname);
+ lxcfs_error("Failed to open %s\n", dirname);
return;
}
continue;
ret = snprintf(path, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
if (ret < 0 || ret >= MAXPATHLEN) {
- fprintf(stderr, "chown_all_cgroup_files: pathname too long under %s\n", dirname);
+ lxcfs_error("Pathname too long under %s\n", dirname);
continue;
}
if (fchownat(fd, path, uid, gid, 0) < 0)
- fprintf(stderr, "Failed to chown file %s to %u:%u", path, uid, gid);
+ lxcfs_error("Failed to chown file %s to %u:%u", path, uid, gid);
}
closedir(d);
}
rc = snprintf(pathname, MAXPATHLEN, "%s/%s", dirname, direntp->d_name);
if (rc < 0 || rc >= MAXPATHLEN) {
- fprintf(stderr, "pathname too long\n");
+ lxcfs_error("%s\n", "Pathname too long.");
continue;
}
ret = true;
if (closedir(dir) < 0) {
- fprintf(stderr, "%s: failed to close directory %s: %s\n", __func__, dirname, strerror(errno));
+ lxcfs_error("Failed to close directory %s: %s\n", dirname, strerror(errno));
ret = false;
}
cg = alloca(len);
ret = snprintf(cg, len, "%s%s", *cgroup == '/' ? "." : "", cgroup);
if (ret < 0 || (size_t)ret >= len) {
- fprintf(stderr, "%s: pathname too long under %s\n", __func__, cgroup);
+ lxcfs_error("Pathname too long under %s\n", cgroup);
return false;
}
ret = snprintf(pathname, MAXPATHLEN, "%s/%s", cg, dirent->d_name);
if (ret < 0 || ret >= MAXPATHLEN) {
- fprintf(stderr, "%s: pathname too long under %s\n", __func__, cg);
+ lxcfs_error("Pathname too long under %s\n", cg);
continue;
}
ret = fstatat(cfd, pathname, &mystat, AT_SYMLINK_NOFOLLOW);
if (ret) {
- fprintf(stderr, "%s: failed to stat %s: %s\n", __func__, pathname, strerror(errno));
+ lxcfs_error("Failed to stat %s: %s\n", pathname, strerror(errno));
continue;
}
if ((!directories && !S_ISREG(mystat.st_mode)) ||
sz++;
}
if (closedir(dir) < 0) {
- fprintf(stderr, "%s: failed closedir for %s: %s\n", __func__, cgroup, strerror(errno));
+ lxcfs_error("Failed closedir for %s: %s\n", cgroup, strerror(errno));
return false;
}
return true;
{
struct cgfs_files *entry = cgfs_get_key(controller, cgroup, dir_entry);
if (!entry) {
- fprintf(stderr, "%s: Error getting files under %s:%s\n",
- __func__, controller, cgroup);
+ lxcfs_error("Error getting files under %s:%s\n", controller,
+ cgroup);
}
return entry;
}
* uids wrapped around - unexpected as this is a procfile,
* so just bail.
*/
- fprintf(stderr, "pid wrapparound at entry %u %u %u in %s\n",
+ lxcfs_error("pid wrapparound at entry %u %u %u in %s\n",
nsuid, hostuid, count, line);
return -1;
}
char *start, *end;
if (strlen(taskcg) <= strlen(querycg)) {
- fprintf(stderr, "%s: I was fed bad input\n", __func__);
+ lxcfs_error("%s\n", "I was fed bad input.");
return NULL;
}
const char *p1;
char *contr, *slash;
- if (strlen(path) < 9)
+ if (strlen(path) < 9) {
+ errno = EACCES;
return NULL;
- if (*(path+7) != '/')
+ }
+ if (*(path + 7) != '/') {
+ errno = EINVAL;
return NULL;
- p1 = path+8;
+ }
+ p1 = path + 8;
contr = strdupa(p1);
- if (!contr)
+ if (!contr) {
+ errno = ENOMEM;
return NULL;
+ }
slash = strstr(contr, "/");
if (slash)
*slash = '\0';
int i;
- for (i = 0; i < num_hierarchies; i++) {
+ for (i = 0; i < num_hierarchies; i++) {
if (hierarchies[i] && strcmp(hierarchies[i], contr) == 0)
return hierarchies[i];
}
+ errno = ENOENT;
return NULL;
}
{
const char *p1;
- if (strlen(path) < 9)
+ if (strlen(path) < 9) {
+ errno = EACCES;
return NULL;
- p1 = strstr(path+8, "/");
- if (!p1)
+ }
+ p1 = strstr(path + 8, "/");
+ if (!p1) {
+ errno = EINVAL;
return NULL;
- return p1+1;
+ }
+ errno = 0;
+ return p1 + 1;
}
/*
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EIO;
+ return -errno;
cgroup = find_cgroup_in_path(path);
if (!cgroup) {
/* this is just /cgroup/controller, return it as a dir */
// return list of keys for the controller, and list of child cgroups
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EIO;
+ return -errno;
cgroup = find_cgroup_in_path(path);
if (!cgroup) {
struct fuse_context *fc = fuse_get_context();
char **clist = NULL;
+ if (filler(buf, ".", NULL, 0) != 0 || filler(buf, "..", NULL, 0) != 0)
+ return -EIO;
+
if (d->type != LXC_TYPE_CGDIR) {
- fprintf(stderr, "Internal error: file cache info used in readdir\n");
+ lxcfs_error("%s\n", "Internal error: file cache info used in readdir.");
return -EIO;
}
if (!d->cgroup && !d->controller) {
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EIO;
+ return -errno;
cgroup = find_cgroup_in_path(path);
if (!cgroup)
- return -EINVAL;
+ return -errno;
get_cgdir_and_path(cgroup, &cgdir, &last);
if (!last) {
struct cgfs_files *k = NULL;
struct fuse_context *fc = fuse_get_context();
- if (strcmp(path, "/cgroup") == 0) {
- if ((mode & W_OK) == 0)
- return -EACCES;
+ if (strcmp(path, "/cgroup") == 0)
return 0;
- }
if (!fc)
return -EIO;
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EIO;
+ return -errno;
cgroup = find_cgroup_in_path(path);
if (!cgroup) {
// access("/sys/fs/cgroup/systemd", mode) - rx allowed, w not
return false;
if ((epfd = epoll_create(1)) < 0) {
- fprintf(stderr, "Failed to create epoll socket: %m\n");
+ 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) {
- fprintf(stderr, "Failed adding socket to epoll: %m\n");
+ lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
close(epfd);
return false;
}
if (pingfirst) {
if (msgrecv(sock, buf, 1) != 1) {
- fprintf(stderr, "%s: Error getting reply from server over socketpair\n",
- __func__);
+ lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
return SEND_CREDS_FAIL;
}
}
msg.msg_iovlen = 1;
if (sendmsg(sock, &msg, 0) < 0) {
- fprintf(stderr, "%s: failed at sendmsg: %s\n", __func__,
- strerror(errno));
+ lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
if (errno == 3)
return SEND_CREDS_NOTSK;
return SEND_CREDS_FAIL;
cred->gid = -1;
if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
- fprintf(stderr, "Failed to set passcred: %s\n", strerror(errno));
+ lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
return false;
}
buf[0] = '1';
if (write(sock, buf, 1) != 1) {
- fprintf(stderr, "Failed to start write on scm fd: %s\n", strerror(errno));
+ lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
return false;
}
msg.msg_iovlen = 1;
if (!wait_for_sock(sock, 2)) {
- fprintf(stderr, "Timed out waiting for scm_cred: %s\n",
- strerror(errno));
+ lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
return false;
}
ret = recvmsg(sock, &msg, MSG_DONTWAIT);
if (ret < 0) {
- fprintf(stderr, "Failed to receive scm_cred: %s\n",
- strerror(errno));
+ lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
return false;
}
char b = '1';
close(args->cpipe[0]);
- if (write(args->cpipe[1], &b, sizeof(char)) < 0) {
- fprintf(stderr, "%s (child): error on write: %s\n",
- __func__, strerror(errno));
- }
+ 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);
}
// read converted results
if (!wait_for_sock(sock[0], 2)) {
- fprintf(stderr, "%s: timed out waiting for pid from child: %s\n",
- __func__, strerror(errno));
+ lxcfs_error("Timed out waiting for pid from child: %s.\n", strerror(errno));
goto out;
}
if (read(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
- fprintf(stderr, "%s: error reading pid from child: %s\n",
- __func__, strerror(errno));
+ lxcfs_error("Error reading pid from child: %s.\n", strerror(errno));
goto out;
}
must_strcat_pid(d, &sz, &asz, qpid);
v = '1';
if (send_creds(sock[0], &cred, v, true) != SEND_CREDS_OK) {
// failed to ask child to exit
- fprintf(stderr, "%s: failed to ask child to exit: %s\n",
- __func__, strerror(errno));
+ lxcfs_error("Failed to ask child to exit: %s.\n", strerror(errno));
goto out;
}
bool r;
if (f->type != LXC_TYPE_CGFILE) {
- fprintf(stderr, "Internal error: directory cache info used in cg_read\n");
+ lxcfs_error("%s\n", "Internal error: directory cache info used in cg_read.");
return -EIO;
}
cred.gid = 0;
while (1) {
if (!wait_for_sock(sock, 2)) {
- fprintf(stderr, "%s: timeout reading from parent\n", __func__);
+ lxcfs_error("%s\n", "Timeout reading from parent.");
return 1;
}
if ((ret = read(sock, &vpid, sizeof(pid_t))) != sizeof(pid_t)) {
- fprintf(stderr, "%s: bad read from parent: %s\n",
- __func__, strerror(errno));
+ lxcfs_error("Bad read from parent: %s.\n", strerror(errno));
return 1;
}
if (vpid == -1) // done
*gid = -1;
sprintf(line, "/proc/%d/status", pid);
if ((f = fopen(line, "r")) == NULL) {
- fprintf(stderr, "Error opening %s: %s\n", line, strerror(errno));
+ 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) {
- fprintf(stderr, "bad uid line for pid %u\n", pid);
+ 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) {
- fprintf(stderr, "bad gid line for pid %u\n", pid);
+ lxcfs_error("bad gid line for pid %u\n", pid);
fclose(f);
return;
}
char v;
if (write(sock[0], &qpid, sizeof(qpid)) != sizeof(qpid)) {
- fprintf(stderr, "%s: error writing pid to child: %s\n",
- __func__, strerror(errno));
+ lxcfs_error("Error writing pid to child: %s.\n", strerror(errno));
goto out;
}
/* All good, write the value */
qpid = -1;
if (write(sock[0], &qpid ,sizeof(qpid)) != sizeof(qpid))
- fprintf(stderr, "Warning: failed to ask child to exit\n");
+ lxcfs_error("%s\n", "Warning: failed to ask child to exit.");
if (!fail)
answer = true;
bool r;
if (f->type != LXC_TYPE_CGFILE) {
- fprintf(stderr, "Internal error: directory cache info used in cg_write\n");
+ lxcfs_error("%s\n", "Internal error: directory cache info used in cg_write.");
return -EIO;
}
return -EIO;
if (strcmp(path, "/cgroup") == 0)
- return -EINVAL;
+ return -EPERM;
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EINVAL;
+ return errno == ENOENT ? -EPERM : -errno;
+
cgroup = find_cgroup_in_path(path);
if (!cgroup)
/* this is just /cgroup/controller */
- return -EINVAL;
+ return -EPERM;
get_cgdir_and_path(cgroup, &cgdir, &last);
return -EIO;
if (strcmp(path, "/cgroup") == 0)
- return -EINVAL;
+ return -EPERM;
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EINVAL;
+ return errno == ENOENT ? -EPERM : -errno;
+
cgroup = find_cgroup_in_path(path);
if (!cgroup)
/* this is just /cgroup/controller */
- return -EINVAL;
+ return -EPERM;
get_cgdir_and_path(cgroup, &cgdir, &last);
if (!fc)
return -EIO;
-
controller = pick_controller_from_path(fc, path);
if (!controller)
- return -EINVAL;
+ return errno == ENOENT ? -EPERM : -errno;
cgroup = find_cgroup_in_path(path);
if (!cgroup)
- return -EINVAL;
+ return -errno;
get_cgdir_and_path(cgroup, &cgdir, &last);
if (!last)
else if (last && strcmp(next, last) == 0)
ret = -EEXIST;
else
- ret = -ENOENT;
+ ret = -EPERM;
goto out;
}
return -EIO;
controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -EINVAL;
+ if (!controller) /* Someone's trying to delete "/cgroup". */
+ return -EPERM;
cgroup = find_cgroup_in_path(path);
- if (!cgroup)
- return -EINVAL;
+ if (!cgroup) /* Someone's trying to delete a controller e.g. "/blkio". */
+ return -EPERM;
get_cgdir_and_path(cgroup, &cgdir, &last);
if (!last) {
- ret = -EINVAL;
+ /* 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;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
//skip first line
if (getline(&line, &linelen, f) < 0) {
- fprintf(stderr, "proc_stat_read read first line failed\n");
+ lxcfs_error("%s\n", "proc_stat_read read first line failed.");
goto err;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
cache += cpuall_len;
} else{
/* shouldn't happen */
- fprintf(stderr, "proc_stat_read copy cpuall failed, cpuall_len=%d\n", cpuall_len);
+ lxcfs_error("proc_stat_read copy cpuall failed, cpuall_len=%d.", cpuall_len);
cpuall_len = 0;
}
goto err;
}
if (l >= cache_size) {
- fprintf(stderr, "Internal error: truncated write to cache\n");
+ lxcfs_error("%s\n", "Internal error: truncated write to cache.");
rv = 0;
goto err;
}
int proc_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
struct fuse_file_info *fi)
{
- if (filler(buf, "cpuinfo", NULL, 0) != 0 ||
- filler(buf, "meminfo", NULL, 0) != 0 ||
- filler(buf, "stat", NULL, 0) != 0 ||
- filler(buf, "uptime", NULL, 0) != 0 ||
- filler(buf, "diskstats", NULL, 0) != 0 ||
- filler(buf, "swaps", NULL, 0) != 0)
+ if (filler(buf, ".", NULL, 0) != 0 ||
+ filler(buf, "..", NULL, 0) != 0 ||
+ filler(buf, "cpuinfo", NULL, 0) != 0 ||
+ filler(buf, "meminfo", NULL, 0) != 0 ||
+ filler(buf, "stat", NULL, 0) != 0 ||
+ filler(buf, "uptime", NULL, 0) != 0 ||
+ filler(buf, "diskstats", NULL, 0) != 0 ||
+ filler(buf, "swaps", NULL, 0) != 0)
return -EINVAL;
return 0;
}
if (!makeme)
return false;
if (mkdir(makeme, mode) && errno != EEXIST) {
- fprintf(stderr, "failed to create directory '%s': %s",
+ lxcfs_error("Failed to create directory '%s': %s.\n",
makeme, strerror(errno));
free(makeme);
return false;
static bool umount_if_mounted(void)
{
if (umount2(BASEDIR, MNT_DETACH) < 0 && errno != EINVAL) {
- fprintf(stderr, "failed to unmount %s: %s.\n", BASEDIR, strerror(errno));
+ lxcfs_error("Failed to unmount %s: %s.\n", BASEDIR, strerror(errno));
return false;
}
return true;
}
-static int pivot_enter(void)
+/* __typeof__ should be safe to use with all compilers. */
+typedef __typeof__(((struct statfs *)NULL)->f_type) fs_type_magic;
+static bool has_fs_type(const struct statfs *fs, fs_type_magic magic_val)
+{
+ return (fs->f_type == (fs_type_magic)magic_val);
+}
+
+/*
+ * looking at fs/proc_namespace.c, it appears we can
+ * actually expect the rootfs entry to very specifically contain
+ * " - rootfs rootfs "
+ * IIUC, so long as we've chrooted so that rootfs is not our root,
+ * the rootfs entry should always be skipped in mountinfo contents.
+ */
+static bool is_on_ramfs(void)
+{
+ FILE *f;
+ char *p, *p2;
+ char *line = NULL;
+ size_t len = 0;
+ int i;
+
+ f = fopen("/proc/self/mountinfo", "r");
+ if (!f)
+ return false;
+
+ while (getline(&line, &len, f) != -1) {
+ for (p = line, i = 0; p && i < 4; i++)
+ p = strchr(p + 1, ' ');
+ if (!p)
+ continue;
+ p2 = strchr(p + 1, ' ');
+ if (!p2)
+ continue;
+ *p2 = '\0';
+ if (strcmp(p + 1, "/") == 0) {
+ // this is '/'. is it the ramfs?
+ p = strchr(p2 + 1, '-');
+ if (p && strncmp(p, "- rootfs rootfs ", 16) == 0) {
+ free(line);
+ fclose(f);
+ return true;
+ }
+ }
+ }
+ free(line);
+ fclose(f);
+ return false;
+}
+
+static int pivot_enter()
{
int ret = -1, oldroot = -1, newroot = -1;
oldroot = open("/", O_DIRECTORY | O_RDONLY);
if (oldroot < 0) {
- fprintf(stderr, "%s: Failed to open old root for fchdir.\n", __func__);
+ lxcfs_error("%s\n", "Failed to open old root for fchdir.");
return ret;
}
newroot = open(ROOTDIR, O_DIRECTORY | O_RDONLY);
if (newroot < 0) {
- fprintf(stderr, "%s: Failed to open new root for fchdir.\n", __func__);
+ lxcfs_error("%s\n", "Failed to open new root for fchdir.");
goto err;
}
/* change into new root fs */
if (fchdir(newroot) < 0) {
- fprintf(stderr, "%s: Failed to change directory to new rootfs: %s.\n", __func__, ROOTDIR);
+ lxcfs_error("Failed to change directory to new rootfs: %s.\n", ROOTDIR);
goto err;
}
/* pivot_root into our new root fs */
if (pivot_root(".", ".") < 0) {
- fprintf(stderr, "%s: pivot_root() syscall failed: %s.\n", __func__, strerror(errno));
+ lxcfs_error("pivot_root() syscall failed: %s.\n", strerror(errno));
goto err;
}
* to the old-root.
*/
if (fchdir(oldroot) < 0) {
- fprintf(stderr, "%s: Failed to enter old root.\n", __func__);
+ lxcfs_error("%s\n", "Failed to enter old root.");
goto err;
}
+
if (umount2(".", MNT_DETACH) < 0) {
- fprintf(stderr, "%s: Failed to detach old root.\n", __func__);
+ lxcfs_error("%s\n", "Failed to detach old root.");
goto err;
}
if (fchdir(newroot) < 0) {
- fprintf(stderr, "%s: Failed to re-enter new root.\n", __func__);
+ lxcfs_error("%s\n", "Failed to re-enter new root.");
goto err;
}
close(oldroot);
if (newroot > 0)
close(newroot);
+
return ret;
}
+static int chroot_enter()
+{
+ if (mount(ROOTDIR, "/", NULL, MS_REC | MS_BIND, NULL)) {
+ lxcfs_error("Failed to recursively bind-mount %s into /.", ROOTDIR);
+ return -1;
+ }
+
+ if (chroot(".") < 0) {
+ lxcfs_error("Call to chroot() failed: %s.\n", strerror(errno));
+ return -1;
+ }
+
+ if (chdir("/") < 0) {
+ lxcfs_error("Failed to change directory: %s.\n", strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+static int permute_and_enter(void)
+{
+ struct statfs sb;
+
+ if (statfs("/", &sb) < 0) {
+ lxcfs_error("%s\n", "Could not stat / mountpoint.");
+ return -1;
+ }
+
+ /* has_fs_type() is not reliable. When the ramfs is a tmpfs it will
+ * likely report TMPFS_MAGIC. Hence, when it reports no we still check
+ * /proc/1/mountinfo. */
+ if (has_fs_type(&sb, RAMFS_MAGIC) || is_on_ramfs())
+ return chroot_enter();
+
+ if (pivot_enter() < 0) {
+ lxcfs_error("%s\n", "Could not perform pivot root.");
+ return -1;
+ }
+
+ return 0;
+}
+
/* Prepare our new clean root. */
-static int pivot_prepare(void)
+static int permute_prepare(void)
{
if (mkdir(ROOTDIR, 0700) < 0 && errno != EEXIST) {
- fprintf(stderr, "%s: Failed to create directory for new root.\n", __func__);
+ lxcfs_error("%s\n", "Failed to create directory for new root.");
return -1;
}
if (mount("/", ROOTDIR, NULL, MS_BIND, 0) < 0) {
- fprintf(stderr, "%s: Failed to bind-mount / for new root: %s.\n", __func__, strerror(errno));
+ lxcfs_error("Failed to bind-mount / for new root: %s.\n", strerror(errno));
return -1;
}
if (mount(RUNTIME_PATH, ROOTDIR RUNTIME_PATH, NULL, MS_BIND, 0) < 0) {
- fprintf(stderr, "%s: Failed to bind-mount /run into new root: %s.\n", __func__, strerror(errno));
+ lxcfs_error("Failed to bind-mount /run into new root: %s.\n", strerror(errno));
return -1;
}
if (mount(BASEDIR, ROOTDIR BASEDIR, NULL, MS_REC | MS_MOVE, 0) < 0) {
- printf("%s: failed to move " BASEDIR " into new root: %s.\n", __func__, strerror(errno));
+ printf("Failed to move " BASEDIR " into new root: %s.\n", strerror(errno));
return -1;
}
return 0;
}
-static bool pivot_new_root(void)
+/* Calls chroot() on ramfs, pivot_root() in all other cases. */
+static bool permute_root(void)
{
/* Prepare new root. */
- if (pivot_prepare() < 0)
+ if (permute_prepare() < 0)
return false;
/* Pivot into new root. */
- if (pivot_enter() < 0)
+ if (permute_and_enter() < 0)
return false;
return true;
}
-static bool setup_cgfs_dir(void)
+static bool cgfs_prepare_mounts(void)
{
if (!mkdir_p(BASEDIR, 0700)) {
- fprintf(stderr, "Failed to create lxcfs cgroup mountpoint.\n");
+ lxcfs_error("%s\n", "Failed to create lxcfs cgroup mountpoint.");
return false;
}
if (!umount_if_mounted()) {
- fprintf(stderr, "Failed to clean up old lxcfs cgroup mountpoint.\n");
+ lxcfs_error("%s\n", "Failed to clean up old lxcfs cgroup mountpoint.");
return false;
}
if (unshare(CLONE_NEWNS) < 0) {
- fprintf(stderr, "%s: Failed to unshare mount namespace: %s.\n", __func__, strerror(errno));
+ lxcfs_error("Failed to unshare mount namespace: %s.\n", strerror(errno));
return false;
}
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0) < 0) {
- fprintf(stderr, "%s: Failed to remount / private: %s.\n", __func__, strerror(errno));
+ lxcfs_error("Failed to remount / private: %s.\n", strerror(errno));
return false;
}
if (mount("tmpfs", BASEDIR, "tmpfs", 0, "size=100000,mode=700") < 0) {
- fprintf(stderr, "Failed to mount tmpfs over lxcfs cgroup mountpoint.\n");
+ lxcfs_error("%s\n", "Failed to mount tmpfs over lxcfs cgroup mountpoint.");
return false;
}
return true;
}
-static bool do_mount_cgroups(void)
+static bool cgfs_mount_hierarchies(void)
{
char *target;
size_t clen, len;
return false;
}
if (mount(controller, target, "cgroup", 0, controller) < 0) {
- fprintf(stderr, "Failed mounting cgroup %s\n", controller);
+ lxcfs_error("Failed mounting cgroup %s\n", controller);
free(target);
return false;
}
static bool cgfs_setup_controllers(void)
{
- if (!setup_cgfs_dir())
+ if (!cgfs_prepare_mounts())
return false;
- if (!do_mount_cgroups()) {
- fprintf(stderr, "Failed to set up private lxcfs cgroup mounts.\n");
+ if (!cgfs_mount_hierarchies()) {
+ lxcfs_error("%s\n", "Failed to set up private lxcfs cgroup mounts.");
return false;
}
- if (!pivot_new_root())
+ if (!permute_root())
return false;
return true;
static void __attribute__((constructor)) collect_and_mount_subsystems(void)
{
FILE *f;
- char *line = NULL;
+ char *cret, *line = NULL;
+ char cwd[MAXPATHLEN];
size_t len = 0;
int i, init_ns = -1;
if ((f = fopen("/proc/self/cgroup", "r")) == NULL) {
- fprintf(stderr, "Error opening /proc/self/cgroup: %s\n", strerror(errno));
+ lxcfs_error("Error opening /proc/self/cgroup: %s\n", strerror(errno));
return;
}
+
while (getline(&line, &len, f) != -1) {
char *p, *p2;
/* Preserve initial namespace. */
init_ns = preserve_ns(getpid());
- if (init_ns < 0)
+ if (init_ns < 0) {
+ lxcfs_error("%s\n", "Failed to preserve initial mount namespace.");
goto out;
+ }
fd_hierarchies = malloc(sizeof(int *) * num_hierarchies);
- if (!fd_hierarchies)
+ if (!fd_hierarchies) {
+ lxcfs_error("%s\n", strerror(errno));
goto out;
+ }
for (i = 0; i < num_hierarchies; i++)
fd_hierarchies[i] = -1;
+ cret = getcwd(cwd, MAXPATHLEN);
+ if (!cret)
+ lxcfs_debug("Could not retrieve current working directory: %s.\n", strerror(errno));
+
/* This function calls unshare(CLONE_NEWNS) our initial mount namespace
* to privately mount lxcfs cgroups. */
- if (!cgfs_setup_controllers())
+ if (!cgfs_setup_controllers()) {
+ lxcfs_error("%s\n", "Failed to setup private cgroup mounts for lxcfs.");
goto out;
+ }
- if (setns(init_ns, 0) < 0)
+ if (setns(init_ns, 0) < 0) {
+ lxcfs_error("Failed to switch back to initial mount namespace: %s.\n", strerror(errno));
goto out;
+ }
+
+ if (!cret || chdir(cwd) < 0)
+ lxcfs_debug("Could not change back to original working directory: %s.\n", strerror(errno));
print_subsystems();
{
int i;
+ lxcfs_debug("%s\n", "Running destructor for liblxcfs.");
+
for (i = 0; i < num_hierarchies; i++) {
if (hierarchies[i])
free(hierarchies[i]);
projects / mirror_lxcfs.git / blobdiff