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core/namespace: modernize mount_private_dev

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This commit is contained in:
Mike Yuan 2024-04-27 14:25:36 +08:00
parent 6117dda8de
commit 66825795b4
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GPG Key ID: 417471C0A40F58B3
1 changed files with 42 additions and 61 deletions
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103
src/core/namespace.c
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@ -976,7 +976,20 @@ add_symlink:
return 0;
}
static char *settle_runtime_dir(RuntimeScope scope) {
static int bind_mount_device_dir(const char *temporary_mount, const char *dir) {
const char *t;
assert(temporary_mount);
assert(dir);
assert(path_is_absolute(dir));
t = strjoina(temporary_mount, dir);
(void) mkdir(t, 0755);
return mount_nofollow_verbose(LOG_DEBUG, dir, t, NULL, MS_BIND, NULL);
}
static char* settle_runtime_dir(RuntimeScope scope) {
char *runtime_dir;
if (scope != RUNTIME_SCOPE_USER)
@ -1017,8 +1030,8 @@ static int mount_private_dev(MountEntry *m, RuntimeScope scope) {
"/dev/urandom\0"
"/dev/tty\0";
_cleanup_free_ char *temporary_mount = NULL;
const char *dev = NULL, *devpts = NULL, *devshm = NULL, *devhugepages = NULL, *devmqueue = NULL, *devlog = NULL, *devptmx = NULL;
_cleanup_(rmdir_and_freep) char *temporary_mount = NULL;
_cleanup_(umount_and_rmdir_and_freep) char *dev = NULL;
bool can_mknod = true;
int r;
@ -1028,67 +1041,56 @@ static int mount_private_dev(MountEntry *m, RuntimeScope scope) {
if (r < 0)
return r;
dev = strjoina(temporary_mount, "/dev");
dev = path_join(temporary_mount, "dev");
if (!dev)
return -ENOMEM;
(void) mkdir(dev, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=0755" TMPFS_LIMITS_PRIVATE_DEV);
if (r < 0)
goto fail;
return r;
r = label_fix_full(AT_FDCWD, dev, "/dev", 0);
if (r < 0) {
log_debug_errno(r, "Failed to fix label of '%s' as /dev: %m", dev);
goto fail;
}
devpts = strjoina(temporary_mount, "/dev/pts");
(void) mkdir(devpts, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/pts", devpts, NULL, MS_BIND, NULL);
if (r < 0)
goto fail;
return log_debug_errno(r, "Failed to fix label of '%s' as /dev/: %m", dev);
r = bind_mount_device_dir(temporary_mount, "/dev/pts");
if (r < 0)
return r;
/* /dev/ptmx can either be a device node or a symlink to /dev/pts/ptmx.
* When /dev/ptmx a device node, /dev/pts/ptmx has 000 permissions making it inaccessible.
* Thus, in that case make a clone.
* In nspawn and other containers it will be a symlink, in that case make it a symlink. */
r = is_symlink("/dev/ptmx");
if (r < 0) {
log_debug_errno(r, "Failed to detect whether /dev/ptmx is a symlink or not: %m");
goto fail;
} else if (r > 0) {
devptmx = strjoina(temporary_mount, "/dev/ptmx");
if (symlink("pts/ptmx", devptmx) < 0) {
r = log_debug_errno(errno, "Failed to create a symlink '%s' to pts/ptmx: %m", devptmx);
goto fail;
}
if (r < 0)
return log_debug_errno(r, "Failed to detect whether /dev/ptmx is a symlink or not: %m");
if (r > 0) {
const char *devptmx = strjoina(temporary_mount, "/dev/ptmx");
if (symlink("pts/ptmx", devptmx) < 0)
return log_debug_errno(errno, "Failed to create symlink '%s' to pts/ptmx: %m", devptmx);
} else {
r = clone_device_node("/dev/ptmx", temporary_mount, &can_mknod);
if (r < 0)
goto fail;
return r;
}
devshm = strjoina(temporary_mount, "/dev/shm");
(void) mkdir(devshm, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/shm", devshm, NULL, MS_BIND, NULL);
r = bind_mount_device_dir(temporary_mount, "/dev/shm");
if (r < 0)
goto fail;
return r;
devmqueue = strjoina(temporary_mount, "/dev/mqueue");
(void) mkdir(devmqueue, 0755);
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/mqueue", devmqueue, NULL, MS_BIND, NULL);
FOREACH_STRING(d, "/dev/mqueue", "/dev/hugepages")
(void) bind_mount_device_dir(temporary_mount, d);
devhugepages = strjoina(temporary_mount, "/dev/hugepages");
(void) mkdir(devhugepages, 0755);
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/hugepages", devhugepages, NULL, MS_BIND, NULL);
devlog = strjoina(temporary_mount, "/dev/log");
const char *devlog = strjoina(temporary_mount, "/dev/log");
if (symlink("/run/systemd/journal/dev-log", devlog) < 0)
log_debug_errno(errno, "Failed to create a symlink '%s' to /run/systemd/journal/dev-log, ignoring: %m", devlog);
log_debug_errno(errno, "Failed to create symlink '%s' to /run/systemd/journal/dev-log, ignoring: %m", devlog);
NULSTR_FOREACH(d, devnodes) {
r = clone_device_node(d, temporary_mount, &can_mknod);
/* ENXIO means the *source* is not a device file, skip creation in that case */
if (r < 0 && r != -ENXIO)
goto fail;
return r;
}
r = dev_setup(temporary_mount, UID_INVALID, GID_INVALID);
@ -1106,31 +1108,10 @@ static int mount_private_dev(MountEntry *m, RuntimeScope scope) {
r = mount_nofollow_verbose(LOG_DEBUG, dev, mount_entry_path(m), NULL, MS_MOVE, NULL);
if (r < 0)
goto fail;
(void) rmdir(dev);
(void) rmdir(temporary_mount);
return r;
dev = rmdir_and_free(dev); /* Mount is successfully moved, do not umount() */
return 1;
fail:
if (devpts)
(void) umount_verbose(LOG_DEBUG, devpts, UMOUNT_NOFOLLOW);
if (devshm)
(void) umount_verbose(LOG_DEBUG, devshm, UMOUNT_NOFOLLOW);
if (devhugepages)
(void) umount_verbose(LOG_DEBUG, devhugepages, UMOUNT_NOFOLLOW);
if (devmqueue)
(void) umount_verbose(LOG_DEBUG, devmqueue, UMOUNT_NOFOLLOW);
(void) umount_verbose(LOG_DEBUG, dev, UMOUNT_NOFOLLOW);
(void) rmdir(dev);
(void) rmdir(temporary_mount);
return r;
}
static int mount_bind_dev(const MountEntry *m) {