diff options
author | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-06-01 15:52:09 -0400 |
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committer | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-06-01 15:52:09 -0400 |
commit | bb110bc7433adeb79b4814ef2a1c04e2160be396 (patch) | |
tree | c45048907133b8bbd7e2d86b350436a9ad0ffe8b /src/libcore/umount.c | |
parent | 192d82912f055a2b4a2b5c02f0ef69b002322bba (diff) |
./move.sh
Diffstat (limited to 'src/libcore/umount.c')
-rw-r--r-- | src/libcore/umount.c | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/src/libcore/umount.c b/src/libcore/umount.c new file mode 100644 index 0000000000..a458768e7d --- /dev/null +++ b/src/libcore/umount.c @@ -0,0 +1,613 @@ +/*** + This file is part of systemd. + + Copyright 2010 ProFUSION embedded systems + + 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 <linux/dm-ioctl.h> +#include <linux/loop.h> +#include <string.h> +#include <sys/mount.h> +#include <sys/swap.h> + +#include "libudev.h" + +#include "alloc-util.h" +#include "escape.h" +#include "fd-util.h" +#include "fstab-util.h" +#include "list.h" +#include "mount-setup.h" +#include "path-util.h" +#include "string-util.h" +#include "udev-util.h" +#include "umount.h" +#include "util.h" +#include "virt.h" + +typedef struct MountPoint { + char *path; + char *options; + dev_t devnum; + LIST_FIELDS(struct MountPoint, mount_point); +} MountPoint; + +static void mount_point_free(MountPoint **head, MountPoint *m) { + assert(head); + assert(m); + + LIST_REMOVE(mount_point, *head, m); + + free(m->path); + free(m); +} + +static void mount_points_list_free(MountPoint **head) { + assert(head); + + while (*head) + mount_point_free(head, *head); +} + +static int mount_points_list_get(MountPoint **head) { + _cleanup_fclose_ FILE *proc_self_mountinfo = NULL; + unsigned int i; + int r; + + assert(head); + + proc_self_mountinfo = fopen("/proc/self/mountinfo", "re"); + if (!proc_self_mountinfo) + return -errno; + + for (i = 1;; i++) { + _cleanup_free_ char *path = NULL, *options = NULL; + char *p = NULL; + MountPoint *m; + int k; + + k = fscanf(proc_self_mountinfo, + "%*s " /* (1) mount id */ + "%*s " /* (2) parent id */ + "%*s " /* (3) major:minor */ + "%*s " /* (4) root */ + "%ms " /* (5) mount point */ + "%*s" /* (6) mount flags */ + "%*[^-]" /* (7) optional fields */ + "- " /* (8) separator */ + "%*s " /* (9) file system type */ + "%*s" /* (10) mount source */ + "%ms" /* (11) mount options */ + "%*[^\n]", /* some rubbish at the end */ + &path, &options); + if (k != 2) { + if (k == EOF) + break; + + log_warning("Failed to parse /proc/self/mountinfo:%u.", i); + continue; + } + + r = cunescape(path, UNESCAPE_RELAX, &p); + if (r < 0) + return r; + + /* Ignore mount points we can't unmount because they + * are API or because we are keeping them open (like + * /dev/console). Also, ignore all mounts below API + * file systems, since they are likely virtual too, + * and hence not worth spending time on. Also, in + * unprivileged containers we might lack the rights to + * unmount these things, hence don't bother. */ + if (mount_point_is_api(p) || + mount_point_ignore(p) || + path_startswith(p, "/dev") || + path_startswith(p, "/sys") || + path_startswith(p, "/proc")) { + free(p); + continue; + } + + m = new0(MountPoint, 1); + if (!m) { + free(p); + return -ENOMEM; + } + + m->path = p; + m->options = options; + options = NULL; + + LIST_PREPEND(mount_point, *head, m); + } + + return 0; +} + +static int swap_list_get(MountPoint **head) { + _cleanup_fclose_ FILE *proc_swaps = NULL; + unsigned int i; + int r; + + assert(head); + + proc_swaps = fopen("/proc/swaps", "re"); + if (!proc_swaps) + return (errno == ENOENT) ? 0 : -errno; + + (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n"); + + for (i = 2;; i++) { + MountPoint *swap; + char *dev = NULL, *d; + int k; + + k = fscanf(proc_swaps, + "%ms " /* device/file */ + "%*s " /* type of swap */ + "%*s " /* swap size */ + "%*s " /* used */ + "%*s\n", /* priority */ + &dev); + + if (k != 1) { + if (k == EOF) + break; + + log_warning("Failed to parse /proc/swaps:%u.", i); + free(dev); + continue; + } + + if (endswith(dev, " (deleted)")) { + free(dev); + continue; + } + + r = cunescape(dev, UNESCAPE_RELAX, &d); + free(dev); + if (r < 0) + return r; + + swap = new0(MountPoint, 1); + if (!swap) { + free(d); + return -ENOMEM; + } + + swap->path = d; + LIST_PREPEND(mount_point, *head, swap); + } + + return 0; +} + +static int loopback_list_get(MountPoint **head) { + _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; + struct udev_list_entry *item = NULL, *first = NULL; + _cleanup_udev_unref_ struct udev *udev = NULL; + int r; + + assert(head); + + udev = udev_new(); + if (!udev) + return -ENOMEM; + + e = udev_enumerate_new(udev); + if (!e) + return -ENOMEM; + + r = udev_enumerate_add_match_subsystem(e, "block"); + if (r < 0) + return r; + + r = udev_enumerate_add_match_sysname(e, "loop*"); + if (r < 0) + return r; + + r = udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL); + if (r < 0) + return r; + + r = udev_enumerate_scan_devices(e); + if (r < 0) + return r; + + first = udev_enumerate_get_list_entry(e); + udev_list_entry_foreach(item, first) { + MountPoint *lb; + _cleanup_udev_device_unref_ struct udev_device *d; + char *loop; + const char *dn; + + d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); + if (!d) + return -ENOMEM; + + dn = udev_device_get_devnode(d); + if (!dn) + continue; + + loop = strdup(dn); + if (!loop) + return -ENOMEM; + + lb = new0(MountPoint, 1); + if (!lb) { + free(loop); + return -ENOMEM; + } + + lb->path = loop; + LIST_PREPEND(mount_point, *head, lb); + } + + return 0; +} + +static int dm_list_get(MountPoint **head) { + _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; + struct udev_list_entry *item = NULL, *first = NULL; + _cleanup_udev_unref_ struct udev *udev = NULL; + int r; + + assert(head); + + udev = udev_new(); + if (!udev) + return -ENOMEM; + + e = udev_enumerate_new(udev); + if (!e) + return -ENOMEM; + + r = udev_enumerate_add_match_subsystem(e, "block"); + if (r < 0) + return r; + + r = udev_enumerate_add_match_sysname(e, "dm-*"); + if (r < 0) + return r; + + r = udev_enumerate_scan_devices(e); + if (r < 0) + return r; + + first = udev_enumerate_get_list_entry(e); + udev_list_entry_foreach(item, first) { + MountPoint *m; + _cleanup_udev_device_unref_ struct udev_device *d; + dev_t devnum; + char *node; + const char *dn; + + d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); + if (!d) + return -ENOMEM; + + devnum = udev_device_get_devnum(d); + dn = udev_device_get_devnode(d); + if (major(devnum) == 0 || !dn) + continue; + + node = strdup(dn); + if (!node) + return -ENOMEM; + + m = new(MountPoint, 1); + if (!m) { + free(node); + return -ENOMEM; + } + + m->path = node; + m->devnum = devnum; + LIST_PREPEND(mount_point, *head, m); + } + + return 0; +} + +static int delete_loopback(const char *device) { + _cleanup_close_ int fd = -1; + int r; + + fd = open(device, O_RDONLY|O_CLOEXEC); + if (fd < 0) + return errno == ENOENT ? 0 : -errno; + + r = ioctl(fd, LOOP_CLR_FD, 0); + if (r >= 0) + return 1; + + /* ENXIO: not bound, so no error */ + if (errno == ENXIO) + return 0; + + return -errno; +} + +static int delete_dm(dev_t devnum) { + _cleanup_close_ int fd = -1; + int r; + struct dm_ioctl dm = { + .version = {DM_VERSION_MAJOR, + DM_VERSION_MINOR, + DM_VERSION_PATCHLEVEL}, + .data_size = sizeof(dm), + .dev = devnum, + }; + + assert(major(devnum) != 0); + + fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC); + if (fd < 0) + return -errno; + + r = ioctl(fd, DM_DEV_REMOVE, &dm); + return r >= 0 ? 0 : -errno; +} + +static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_error) { + MountPoint *m, *n; + int n_failed = 0; + + assert(head); + + LIST_FOREACH_SAFE(mount_point, m, n, *head) { + + /* If we are in a container, don't attempt to + read-only mount anything as that brings no real + benefits, but might confuse the host, as we remount + the superblock here, not the bind mound. */ + if (detect_container() <= 0) { + _cleanup_free_ char *options = NULL; + /* MS_REMOUNT requires that the data parameter + * should be the same from the original mount + * except for the desired changes. Since we want + * to remount read-only, we should filter out + * rw (and ro too, because it confuses the kernel) */ + (void) fstab_filter_options(m->options, "rw\0ro\0", NULL, NULL, &options); + + /* We always try to remount directories + * read-only first, before we go on and umount + * them. + * + * Mount points can be stacked. If a mount + * point is stacked below / or /usr, we + * cannot umount or remount it directly, + * since there is no way to refer to the + * underlying mount. There's nothing we can do + * about it for the general case, but we can + * do something about it if it is aliased + * somehwere else via a bind mount. If we + * explicitly remount the super block of that + * alias read-only we hence should be + * relatively safe regarding keeping the fs we + * can otherwise not see dirty. */ + log_info("Remounting '%s' read-only with options '%s'.", m->path, options); + (void) mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, options); + } + + /* Skip / and /usr since we cannot unmount that + * anyway, since we are running from it. They have + * already been remounted ro. */ + if (path_equal(m->path, "/") +#ifndef HAVE_SPLIT_USR + || path_equal(m->path, "/usr") +#endif + ) + continue; + + /* Trying to umount. We don't force here since we rely + * on busy NFS and FUSE file systems to return EBUSY + * until we closed everything on top of them. */ + log_info("Unmounting %s.", m->path); + if (umount2(m->path, 0) == 0) { + if (changed) + *changed = true; + + mount_point_free(head, m); + } else if (log_error) { + log_warning_errno(errno, "Could not unmount %s: %m", m->path); + n_failed++; + } + } + + return n_failed; +} + +static int swap_points_list_off(MountPoint **head, bool *changed) { + MountPoint *m, *n; + int n_failed = 0; + + assert(head); + + LIST_FOREACH_SAFE(mount_point, m, n, *head) { + log_info("Deactivating swap %s.", m->path); + if (swapoff(m->path) == 0) { + if (changed) + *changed = true; + + mount_point_free(head, m); + } else { + log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path); + n_failed++; + } + } + + return n_failed; +} + +static int loopback_points_list_detach(MountPoint **head, bool *changed) { + MountPoint *m, *n; + int n_failed = 0, k; + struct stat root_st; + + assert(head); + + k = lstat("/", &root_st); + + LIST_FOREACH_SAFE(mount_point, m, n, *head) { + int r; + struct stat loopback_st; + + if (k >= 0 && + major(root_st.st_dev) != 0 && + lstat(m->path, &loopback_st) >= 0 && + root_st.st_dev == loopback_st.st_rdev) { + n_failed ++; + continue; + } + + log_info("Detaching loopback %s.", m->path); + r = delete_loopback(m->path); + if (r >= 0) { + if (r > 0 && changed) + *changed = true; + + mount_point_free(head, m); + } else { + log_warning_errno(errno, "Could not detach loopback %s: %m", m->path); + n_failed++; + } + } + + return n_failed; +} + +static int dm_points_list_detach(MountPoint **head, bool *changed) { + MountPoint *m, *n; + int n_failed = 0, k; + struct stat root_st; + + assert(head); + + k = lstat("/", &root_st); + + LIST_FOREACH_SAFE(mount_point, m, n, *head) { + int r; + + if (k >= 0 && + major(root_st.st_dev) != 0 && + root_st.st_dev == m->devnum) { + n_failed ++; + continue; + } + + log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum)); + r = delete_dm(m->devnum); + if (r >= 0) { + if (changed) + *changed = true; + + mount_point_free(head, m); + } else { + log_warning_errno(errno, "Could not detach DM %s: %m", m->path); + n_failed++; + } + } + + return n_failed; +} + +int umount_all(bool *changed) { + int r; + bool umount_changed; + LIST_HEAD(MountPoint, mp_list_head); + + LIST_HEAD_INIT(mp_list_head); + r = mount_points_list_get(&mp_list_head); + if (r < 0) + goto end; + + /* retry umount, until nothing can be umounted anymore */ + do { + umount_changed = false; + + mount_points_list_umount(&mp_list_head, &umount_changed, false); + if (umount_changed) + *changed = true; + + } while (umount_changed); + + /* umount one more time with logging enabled */ + r = mount_points_list_umount(&mp_list_head, &umount_changed, true); + if (r <= 0) + goto end; + + end: + mount_points_list_free(&mp_list_head); + + return r; +} + +int swapoff_all(bool *changed) { + int r; + LIST_HEAD(MountPoint, swap_list_head); + + LIST_HEAD_INIT(swap_list_head); + + r = swap_list_get(&swap_list_head); + if (r < 0) + goto end; + + r = swap_points_list_off(&swap_list_head, changed); + + end: + mount_points_list_free(&swap_list_head); + + return r; +} + +int loopback_detach_all(bool *changed) { + int r; + LIST_HEAD(MountPoint, loopback_list_head); + + LIST_HEAD_INIT(loopback_list_head); + + r = loopback_list_get(&loopback_list_head); + if (r < 0) + goto end; + + r = loopback_points_list_detach(&loopback_list_head, changed); + + end: + mount_points_list_free(&loopback_list_head); + + return r; +} + +int dm_detach_all(bool *changed) { + int r; + LIST_HEAD(MountPoint, dm_list_head); + + LIST_HEAD_INIT(dm_list_head); + + r = dm_list_get(&dm_list_head); + if (r < 0) + goto end; + + r = dm_points_list_detach(&dm_list_head, changed); + + end: + mount_points_list_free(&dm_list_head); + + return r; +} |