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Diffstat (limited to 'src/core/switch-root.c')
| -rw-r--r-- | src/core/switch-root.c | 164 |
1 files changed, 0 insertions, 164 deletions
diff --git a/src/core/switch-root.c b/src/core/switch-root.c deleted file mode 100644 index 0ea61dbb29..0000000000 --- a/src/core/switch-root.c +++ /dev/null @@ -1,164 +0,0 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - -/*** - 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 <sys/stat.h> -#include <stdbool.h> -#include <errno.h> -#include <string.h> -#include <sys/mount.h> -#include <unistd.h> -#include <fcntl.h> - -#include "util.h" -#include "path-util.h" -#include "switch-root.h" -#include "mkdir.h" -#include "base-filesystem.h" -#include "missing.h" - -int switch_root(const char *new_root) { - - /* 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; - int r; - - if (path_equal(new_root, "/")) - return 0; - - /* When using pivot_root() we assume that /mnt exists as place - * we can temporarily move the old root to. As we immediately - * unmount it from there it doesn't matter much which - * directory we choose for this, but it should be more likely - * than not that /mnt exists and is suitable as mount point - * and is on the same fs as the old root dir */ - temporary_old_root = strappenda(new_root, "/mnt"); - mkdir_p(temporary_old_root, 0755); - - old_root_remove = in_initrd(); - - if (stat(new_root, &new_root_stat) < 0) { - log_error("Failed to stat directory %s: %m", new_root); - return -errno; - } - - /* Work-around for a kernel bug: for some reason 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("Failed to make \"/\" private mount: %m"); - - NULSTR_FOREACH(i, move_mounts) { - char new_mount[PATH_MAX]; - struct stat sb; - - snprintf(new_mount, sizeof(new_mount), "%s%s", new_root, i); - char_array_0(new_mount); - - mkdir_p(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("Failed to unmount %s: %m", i); - continue; - } - - if (mount(i, new_mount, NULL, MS_MOVE, NULL) < 0) { - log_error("Failed to move mount %s to %s, forcing unmount: %m", i, new_mount); - - if (umount2(i, MNT_FORCE) < 0) - log_warning("Failed to unmount %s: %m", i); - } - } - - r = base_filesystem_create(new_root); - if (r < 0) { - log_error("Failed to create the base filesystem: %s", strerror(-r)); - return r; - } - - if (chdir(new_root) < 0) { - log_error("Failed to change directory to %s: %m", new_root); - return -errno; - } - - 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("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. Since we are - * running off it we need to do this lazily. */ - if (umount2("/mnt", MNT_DETACH) < 0) { - log_error("Failed to umount old root dir /mnt: %m"); - return -errno; - } - - } else if (mount(new_root, "/", NULL, MS_MOVE, NULL) < 0) { - log_error("Failed to mount moving %s to /: %m", new_root); - return -errno; - } - - if (chroot(".") < 0) { - log_error("Failed to change root: %m"); - return -errno; - } - - if (chdir("/") < 0) { - log_error("Failed to change directory: %m"); - return -errno; - } - - if (old_root_fd >= 0) { - struct stat rb; - - if (fstat(old_root_fd, &rb) < 0) - log_warning("Failed to stat old root directory, leaving: %m"); - else { - rm_rf_children(old_root_fd, false, false, &rb); - old_root_fd = -1; - } - } - - return 0; -} |