X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fcore%2Fumount.c;h=ceee70fbea6ebe46b1442fc894125275737bf5ec;hb=f5b51ea7fcb0b6380c3ceb4d4f3f22f647c6fd32;hp=a5a215b2b55847aff7d6870ea9fa96b868169c45;hpb=7c49259fc8f63ade6cb212a43477d7030aaaf423;p=elogind.git diff --git a/src/core/umount.c b/src/core/umount.c index a5a215b2b..ceee70fbe 100644 --- a/src/core/umount.c +++ b/src/core/umount.c @@ -24,28 +24,29 @@ #include #include #include -#include #include #include -#include #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); + LIST_FIELDS(struct MountPoint, mount_point); } MountPoint; static void mount_point_free(MountPoint **head, MountPoint *m) { assert(head); assert(m); - LIST_REMOVE(MountPoint, mount_point, *head, m); + LIST_REMOVE(mount_point, *head, m); free(m->path); free(m); @@ -59,85 +60,79 @@ static void mount_points_list_free(MountPoint **head) { } static int mount_points_list_get(MountPoint **head) { - FILE *proc_self_mountinfo; - char *path, *p; + _cleanup_fclose_ FILE *proc_self_mountinfo = NULL; unsigned int i; - int r; assert(head); - if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re"))) + proc_self_mountinfo = fopen("/proc/self/mountinfo", "re"); + if (!proc_self_mountinfo) return -errno; for (i = 1;; i++) { - int k; + _cleanup_free_ char *path = NULL; + char *p = NULL; MountPoint *m; + int k; - 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) { + 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); + if (k != 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; - } + if (!p) + return -ENOMEM; /* Ignore mount points we can't unmount because they * are API or because we are keeping them open (like - * /dev/console) */ + * /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_equal(p, "/dev/console")) { + path_startswith(p, "/dev") || + path_startswith(p, "/sys") || + path_startswith(p, "/proc")) { free(p); continue; } - if (!(m = new0(MountPoint, 1))) { + m = new0(MountPoint, 1); + if (!m) { free(p); - r = -ENOMEM; - goto finish; + return -ENOMEM; } m->path = p; - LIST_PREPEND(MountPoint, mount_point, *head, m); + LIST_PREPEND(mount_point, *head, m); } - r = 0; - -finish: - fclose(proc_self_mountinfo); - - return r; + return 0; } static int swap_list_get(MountPoint **head) { - FILE *proc_swaps; + _cleanup_fclose_ FILE *proc_swaps = NULL; unsigned int i; - int r; assert(head); @@ -168,7 +163,7 @@ static int swap_list_get(MountPoint **head) { continue; } - if (endswith(dev, "(deleted)")) { + if (endswith(dev, " (deleted)")) { free(dev); continue; } @@ -177,195 +172,157 @@ static int swap_list_get(MountPoint **head) { free(dev); if (!d) { - r = -ENOMEM; - goto finish; + return -ENOMEM; } if (!(swap = new0(MountPoint, 1))) { free(d); - r = -ENOMEM; - goto finish; + return -ENOMEM; } swap->path = d; - LIST_PREPEND(MountPoint, mount_point, *head, swap); + LIST_PREPEND(mount_point, *head, swap); } - r = 0; - -finish: - fclose(proc_swaps); - - return r; + return 0; } static int loopback_list_get(MountPoint **head) { - int r; - struct udev *udev; - struct udev_enumerate *e = NULL; + _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); - if (!(udev = udev_new())) { - r = -ENOMEM; - goto finish; - } + udev = udev_new(); + if (!udev) + return -ENOMEM; - if (!(e = udev_enumerate_new(udev))) { - r = -ENOMEM; - goto finish; - } + 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) { - r = -EIO; - goto finish; - } + r = udev_enumerate_add_match_subsystem(e, "block"); + if (r < 0) + return r; - if (udev_enumerate_scan_devices(e) < 0) { - r = -EIO; - goto finish; - } + 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; - struct udev_device *d; + _cleanup_udev_device_unref_ struct udev_device *d; char *loop; const char *dn; - if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) { - r = -ENOMEM; - goto finish; - } + d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); + if (!d) + return -ENOMEM; - if (!(dn = udev_device_get_devnode(d))) { - udev_device_unref(d); + dn = udev_device_get_devnode(d); + if (!dn) continue; - } loop = strdup(dn); - udev_device_unref(d); - - if (!loop) { - r = -ENOMEM; - goto finish; - } + if (!loop) + return -ENOMEM; - if (!(lb = new0(MountPoint, 1))) { + lb = new0(MountPoint, 1); + if (!lb) { free(loop); - r = -ENOMEM; - goto finish; + return -ENOMEM; } lb->path = loop; - LIST_PREPEND(MountPoint, mount_point, *head, lb); + LIST_PREPEND(mount_point, *head, lb); } - r = 0; - -finish: - if (e) - udev_enumerate_unref(e); - - if (udev) - udev_unref(udev); - - return r; + return 0; } static int dm_list_get(MountPoint **head) { - int r; - struct udev *udev; - struct udev_enumerate *e = NULL; + _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); - if (!(udev = udev_new())) { - r = -ENOMEM; - goto finish; - } + udev = udev_new(); + if (!udev) + return -ENOMEM; - if (!(e = udev_enumerate_new(udev))) { - r = -ENOMEM; - goto finish; - } + 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) { - r = -EIO; - goto finish; - } + r = udev_enumerate_add_match_subsystem(e, "block"); + if (r < 0) + return r; - if (udev_enumerate_scan_devices(e) < 0) { - r = -EIO; - goto finish; - } + r = udev_enumerate_add_match_sysname(e, "dm-*"); + if (r < 0) + return r; - first = udev_enumerate_get_list_entry(e); + 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; - struct udev_device *d; + _cleanup_udev_device_unref_ struct udev_device *d; dev_t devnum; char *node; const char *dn; - if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) { - r = -ENOMEM; - goto finish; - } + 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) { - udev_device_unref(d); + if (major(devnum) == 0 || !dn) continue; - } node = strdup(dn); - udev_device_unref(d); - - if (!node) { - r = -ENOMEM; - goto finish; - } + if (!node) + return -ENOMEM; - if (!(m = new(MountPoint, 1))) { + m = new(MountPoint, 1); + if (!m) { free(node); - r = -ENOMEM; - goto finish; + return -ENOMEM; } m->path = node; m->devnum = devnum; - LIST_PREPEND(MountPoint, mount_point, *head, m); + LIST_PREPEND(mount_point, *head, m); } - r = 0; - -finish: - if (e) - udev_enumerate_unref(e); - - if (udev) - udev_unref(udev); - - return r; + return 0; } static int delete_loopback(const char *device) { - int fd, r; + _cleanup_close_ int fd = -1; + int r; - if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0) + fd = open(device, O_RDONLY|O_CLOEXEC); + if (fd < 0) return errno == ENOENT ? 0 : -errno; r = ioctl(fd, LOOP_CLR_FD, 0); - close_nointr_nofail(fd); - if (r >= 0) return 1; @@ -377,25 +334,23 @@ static int delete_loopback(const char *device) { } static int delete_dm(dev_t devnum) { - int fd, r; - struct dm_ioctl dm; + _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); - if ((fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC)) < 0) + fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC); + if (fd < 0) return -errno; - zero(dm); - dm.version[0] = DM_VERSION_MAJOR; - dm.version[1] = DM_VERSION_MINOR; - dm.version[2] = DM_VERSION_PATCHLEVEL; - - dm.data_size = sizeof(dm); - dm.dev = devnum; - r = ioctl(fd, DM_DEV_REMOVE, &dm); - close_nointr_nofail(fd); - return r >= 0 ? 0 : -errno; } @@ -406,47 +361,52 @@ static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_e 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 - ) { - n_failed++; + ) continue; - } - /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */ - if (umount2(m->path, MNT_FORCE) == 0) { - log_info("Unmounted %s.", m->path); + /* 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 mount_points_list_remount_read_only(MountPoint **head, bool *changed) { - MountPoint *m, *n; - int n_failed = 0; - - assert(head); - - LIST_FOREACH_SAFE(mount_point, m, n, *head) { - - /* Trying to remount read-only */ - if (mount(NULL, m->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0) { - if (changed) - *changed = true; - - mount_point_free(head, m); - } else { - log_warning("Could not remount as read-only %s: %m", m->path); + log_warning_errno(errno, "Could not unmount %s: %m", m->path); n_failed++; } } @@ -461,13 +421,14 @@ static int swap_points_list_off(MountPoint **head, bool *changed) { 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); + log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path); n_failed++; } } @@ -496,14 +457,15 @@ static int loopback_points_list_detach(MountPoint **head, bool *changed) { continue; } - if ((r = delete_loopback(m->path)) >= 0) { - + 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 delete loopback %s: %m", m->path); + log_warning_errno(errno, "Could not detach loopback %s: %m", m->path); n_failed++; } } @@ -530,14 +492,15 @@ static int dm_points_list_detach(MountPoint **head, bool *changed) { continue; } - if ((r = delete_dm(m->devnum)) >= 0) { - - if (r > 0 && changed) + 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 delete dm %s: %m", m->path); + log_warning_errno(errno, "Could not detach DM %s: %m", m->path); n_failed++; } } @@ -548,11 +511,9 @@ static int dm_points_list_detach(MountPoint **head, bool *changed) { int umount_all(bool *changed) { int r; bool umount_changed; - LIST_HEAD(MountPoint, mp_list_head); - LIST_HEAD_INIT(MountPoint, mp_list_head); - + LIST_HEAD_INIT(mp_list_head); r = mount_points_list_get(&mp_list_head); if (r < 0) goto end; @@ -572,8 +533,6 @@ int umount_all(bool *changed) { if (r <= 0) goto end; - r = mount_points_list_remount_read_only(&mp_list_head, changed); - end: mount_points_list_free(&mp_list_head); @@ -584,7 +543,7 @@ int swapoff_all(bool *changed) { int r; LIST_HEAD(MountPoint, swap_list_head); - LIST_HEAD_INIT(MountPoint, swap_list_head); + LIST_HEAD_INIT(swap_list_head); r = swap_list_get(&swap_list_head); if (r < 0) @@ -602,7 +561,7 @@ int loopback_detach_all(bool *changed) { int r; LIST_HEAD(MountPoint, loopback_list_head); - LIST_HEAD_INIT(MountPoint, loopback_list_head); + LIST_HEAD_INIT(loopback_list_head); r = loopback_list_get(&loopback_list_head); if (r < 0) @@ -620,7 +579,7 @@ int dm_detach_all(bool *changed) { int r; LIST_HEAD(MountPoint, dm_list_head); - LIST_HEAD_INIT(MountPoint, dm_list_head); + LIST_HEAD_INIT(dm_list_head); r = dm_list_get(&dm_list_head); if (r < 0)