diff options
Diffstat (limited to 'src/shared/switch-root.c')
| -rw-r--r-- | src/shared/switch-root.c | 167 |
1 files changed, 0 insertions, 167 deletions
diff --git a/src/shared/switch-root.c b/src/shared/switch-root.c deleted file mode 100644 index 4eff4f692e..0000000000 --- a/src/shared/switch-root.c +++ /dev/null @@ -1,167 +0,0 @@ -/*** - This file is part of systemd. - - Copyright 2012 Harald Hoyer, Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <errno.h> -#include <fcntl.h> -#include <limits.h> -#include <stdbool.h> -#include <stdio.h> -#include <sys/mount.h> -#include <sys/stat.h> -#include <unistd.h> - -#include "base-filesystem.h" -#include "fd-util.h" -#include "log.h" -#include "missing.h" -#include "mkdir.h" -#include "path-util.h" -#include "rm-rf.h" -#include "stdio-util.h" -#include "string-util.h" -#include "switch-root.h" -#include "user-util.h" -#include "util.h" - -int switch_root(const char *new_root, const char *oldroot, bool detach_oldroot, unsigned long mountflags) { - - /* Don't try to unmount/move the old "/", there's no way to do it. */ - static const char move_mounts[] = - "/dev\0" - "/proc\0" - "/sys\0" - "/run\0"; - - _cleanup_close_ int old_root_fd = -1; - struct stat new_root_stat; - bool old_root_remove; - const char *i, *temporary_old_root; - - if (path_equal(new_root, "/")) - return 0; - - temporary_old_root = strjoina(new_root, oldroot); - mkdir_p_label(temporary_old_root, 0755); - - old_root_remove = in_initrd(); - - if (stat(new_root, &new_root_stat) < 0) - return log_error_errno(errno, "Failed to stat directory %s: %m", new_root); - - /* Work-around for kernel design: the kernel refuses switching - * root if any file systems are mounted MS_SHARED. Hence - * remount them MS_PRIVATE here as a work-around. - * - * https://bugzilla.redhat.com/show_bug.cgi?id=847418 */ - if (mount(NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL) < 0) - log_warning_errno(errno, "Failed to make \"/\" private mount: %m"); - - NULSTR_FOREACH(i, move_mounts) { - char new_mount[PATH_MAX]; - struct stat sb; - size_t n; - - n = snprintf(new_mount, sizeof new_mount, "%s%s", new_root, i); - if (n >= sizeof new_mount) { - bool move = mountflags & MS_MOVE; - - log_warning("New path is too long, %s: %s%s", - move ? "forcing unmount instead" : "ignoring", - new_root, i); - - if (move) - if (umount2(i, MNT_FORCE) < 0) - log_warning_errno(errno, "Failed to unmount %s: %m", i); - continue; - } - - mkdir_p_label(new_mount, 0755); - - if (stat(new_mount, &sb) < 0 || - sb.st_dev != new_root_stat.st_dev) { - - /* Mount point seems to be mounted already or - * stat failed. Unmount the old mount point. */ - if (umount2(i, MNT_DETACH) < 0) - log_warning_errno(errno, "Failed to unmount %s: %m", i); - continue; - } - - if (mount(i, new_mount, NULL, mountflags, NULL) < 0) { - if (mountflags & MS_MOVE) { - log_error_errno(errno, "Failed to move mount %s to %s, forcing unmount: %m", i, new_mount); - - if (umount2(i, MNT_FORCE) < 0) - log_warning_errno(errno, "Failed to unmount %s: %m", i); - - } else if (mountflags & MS_BIND) - log_error_errno(errno, "Failed to bind mount %s to %s: %m", i, new_mount); - } - } - - /* Do not fail, if base_filesystem_create() fails. Not all - * switch roots are like base_filesystem_create() wants them - * to look like. They might even boot, if they are RO and - * don't have the FS layout. Just ignore the error and - * switch_root() nevertheless. */ - (void) base_filesystem_create(new_root, UID_INVALID, GID_INVALID); - - if (chdir(new_root) < 0) - return log_error_errno(errno, "Failed to change directory to %s: %m", new_root); - - if (old_root_remove) { - old_root_fd = open("/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY|O_DIRECTORY); - if (old_root_fd < 0) - log_warning_errno(errno, "Failed to open root directory: %m"); - } - - /* We first try a pivot_root() so that we can umount the old - * root dir. In many cases (i.e. where rootfs is /), that's - * not possible however, and hence we simply overmount root */ - if (pivot_root(new_root, temporary_old_root) >= 0) { - - /* Immediately get rid of the old root, if detach_oldroot is set. - * Since we are running off it we need to do this lazily. */ - if (detach_oldroot && umount2(oldroot, MNT_DETACH) < 0) - log_error_errno(errno, "Failed to lazily umount old root dir %s, %s: %m", - oldroot, - errno == ENOENT ? "ignoring" : "leaving it around"); - - } else if (mount(new_root, "/", NULL, MS_MOVE, NULL) < 0) - return log_error_errno(errno, "Failed to mount moving %s to /: %m", new_root); - - if (chroot(".") < 0) - return log_error_errno(errno, "Failed to change root: %m"); - - if (chdir("/") < 0) - return log_error_errno(errno, "Failed to change directory: %m"); - - if (old_root_fd >= 0) { - struct stat rb; - - if (fstat(old_root_fd, &rb) < 0) - log_warning_errno(errno, "Failed to stat old root directory, leaving: %m"); - else { - (void) rm_rf_children(old_root_fd, 0, &rb); - old_root_fd = -1; - } - } - - return 0; -} |