picnoir/Systemd
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity
Systemd/src/core/umount.c
Lennart Poettering 71fda00f32 list: make our list macros a bit easier to use by not requring type spec on each invocation 
We can determine the list entry type via the typeof() gcc construct, and
so we should to make the macros much shorter to use.
2013-10-14 06:11:19 +02:00

595 lines
17 KiB
C
Raw Blame History

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 <string.h>
#include <sys/mount.h>
#include <sys/swap.h>
#include <unistd.h>
#include <linux/loop.h>
#include <linux/dm-ioctl.h>
#include "list.h"
#include "mount-setup.h"
#include "umount.h"
#include "path-util.h"
#include "util.h"
#include "virt.h"
#include "libudev.h"
#include "udev-util.h"
typedef struct MountPoint {
char *path;
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) {
FILE *proc_self_mountinfo;
char *path, *p;
unsigned int i;
int r;
assert(head);
if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re")))
return -errno;
for (i = 1;; i++) {
int k;
MountPoint *m;
path = p = NULL;
if ((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 options */
"%*[^-]" /* (7) optional fields */
"- " /* (8) separator */
"%*s " /* (9) file system type */
"%*s" /* (10) mount source */
"%*s" /* (11) mount options 2 */
"%*[^\n]", /* some rubbish at the end */
&path)) != 1) {
if (k == EOF)
break;
log_warning("Failed to parse /proc/self/mountinfo:%u.", i);
free(path);
continue;
}
p = cunescape(path);
free(path);
if (!p) {
r = -ENOMEM;
goto finish;
}
/* Ignore mount points we can't unmount because they
* are API or because we are keeping them open (like
* /dev/console) */
if (mount_point_is_api(p) ||
mount_point_ignore(p) ||
path_equal(p, "/dev/console")) {
free(p);
continue;
}
if (!(m = new0(MountPoint, 1))) {
free(p);
r = -ENOMEM;
goto finish;
}
m->path = p;
LIST_PREPEND(mount_point, *head, m);
}
r = 0;
finish:
fclose(proc_self_mountinfo);
return r;
}
static int swap_list_get(MountPoint **head) {
FILE *proc_swaps;
unsigned int i;
int r;
assert(head);
if (!(proc_swaps = fopen("/proc/swaps", "re")))
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;
if ((k = fscanf(proc_swaps,
"%ms " /* device/file */
"%*s " /* type of swap */
"%*s " /* swap size */
"%*s " /* used */
"%*s\n", /* priority */
&dev)) != 1) {
if (k == EOF)
break;
log_warning("Failed to parse /proc/swaps:%u.", i);
free(dev);
continue;
}
if (endswith(dev, "(deleted)")) {
free(dev);
continue;
}
d = cunescape(dev);
free(dev);
if (!d) {
r = -ENOMEM;
goto finish;
}
if (!(swap = new0(MountPoint, 1))) {
free(d);
r = -ENOMEM;
goto finish;
}
swap->path = d;
LIST_PREPEND(mount_point, *head, swap);
}
r = 0;
finish:
fclose(proc_swaps);
return r;
}
static int loopback_list_get(MountPoint **head) {
_cleanup_udev_unref_ struct udev *udev;
_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
struct udev_list_entry *item = NULL, *first = NULL;
assert(head);
udev = udev_new();
if (!udev)
return -ENOMEM;
e = udev_enumerate_new(udev);
if (!e)
return -ENOMEM;
if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
udev_enumerate_add_match_sysname(e, "loop*") < 0 ||
udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL) < 0)
return -EIO;
if (udev_enumerate_scan_devices(e) < 0)
return -EIO;
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_unref_ struct udev *udev;
_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
struct udev_list_entry *item = NULL, *first = NULL;
assert(head);
udev = udev_new();
if (!udev)
return -ENOMEM;
e = udev_enumerate_new(udev);
if (!e)
return -ENOMEM;
if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
udev_enumerate_add_match_sysname(e, "dm-*") < 0)
return -EIO;
if (udev_enumerate_scan_devices(e) < 0)
return -EIO;
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) {
int fd, r;
if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0)
return errno == ENOENT ? 0 : -errno;
r = ioctl(fd, LOOP_CLR_FD, 0);
close_nointr_nofail(fd);
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(NULL) <= 0) {
/* 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. */
mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
}
/* 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("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("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("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("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;
}
Reference in a new issue View git blame Copy permalink