summaryrefslogtreecommitdiff
path: root/src/basic/mount-util.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/basic/mount-util.c')
-rw-r--r--src/basic/mount-util.c559
1 files changed, 0 insertions, 559 deletions
diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
deleted file mode 100644
index 28dc778969..0000000000
--- a/src/basic/mount-util.c
+++ /dev/null
@@ -1,559 +0,0 @@
-/***
- This file is part of systemd.
-
- Copyright 2010 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 <stdlib.h>
-#include <string.h>
-#include <sys/mount.h>
-#include <sys/stat.h>
-#include <sys/statvfs.h>
-#include <unistd.h>
-
-#include "alloc-util.h"
-#include "escape.h"
-#include "fd-util.h"
-#include "fileio.h"
-#include "hashmap.h"
-#include "mount-util.h"
-#include "parse-util.h"
-#include "path-util.h"
-#include "set.h"
-#include "stdio-util.h"
-#include "string-util.h"
-
-static int fd_fdinfo_mnt_id(int fd, const char *filename, int flags, int *mnt_id) {
- char path[strlen("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
- _cleanup_free_ char *fdinfo = NULL;
- _cleanup_close_ int subfd = -1;
- char *p;
- int r;
-
- if ((flags & AT_EMPTY_PATH) && isempty(filename))
- xsprintf(path, "/proc/self/fdinfo/%i", fd);
- else {
- subfd = openat(fd, filename, O_CLOEXEC|O_PATH);
- if (subfd < 0)
- return -errno;
-
- xsprintf(path, "/proc/self/fdinfo/%i", subfd);
- }
-
- r = read_full_file(path, &fdinfo, NULL);
- if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */
- return -EOPNOTSUPP;
- if (r < 0)
- return -errno;
-
- p = startswith(fdinfo, "mnt_id:");
- if (!p) {
- p = strstr(fdinfo, "\nmnt_id:");
- if (!p) /* The mnt_id field is a relatively new addition */
- return -EOPNOTSUPP;
-
- p += 8;
- }
-
- p += strspn(p, WHITESPACE);
- p[strcspn(p, WHITESPACE)] = 0;
-
- return safe_atoi(p, mnt_id);
-}
-
-
-int fd_is_mount_point(int fd, const char *filename, int flags) {
- union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
- int mount_id = -1, mount_id_parent = -1;
- bool nosupp = false, check_st_dev = true;
- struct stat a, b;
- int r;
-
- assert(fd >= 0);
- assert(filename);
-
- /* First we will try the name_to_handle_at() syscall, which
- * tells us the mount id and an opaque file "handle". It is
- * not supported everywhere though (kernel compile-time
- * option, not all file systems are hooked up). If it works
- * the mount id is usually good enough to tell us whether
- * something is a mount point.
- *
- * If that didn't work we will try to read the mount id from
- * /proc/self/fdinfo/<fd>. This is almost as good as
- * name_to_handle_at(), however, does not return the
- * opaque file handle. The opaque file handle is pretty useful
- * to detect the root directory, which we should always
- * consider a mount point. Hence we use this only as
- * fallback. Exporting the mnt_id in fdinfo is a pretty recent
- * kernel addition.
- *
- * As last fallback we do traditional fstat() based st_dev
- * comparisons. This is how things were traditionally done,
- * but unionfs breaks this since it exposes file
- * systems with a variety of st_dev reported. Also, btrfs
- * subvolumes have different st_dev, even though they aren't
- * real mounts of their own. */
-
- r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags);
- if (r < 0) {
- if (errno == ENOSYS)
- /* This kernel does not support name_to_handle_at()
- * fall back to simpler logic. */
- goto fallback_fdinfo;
- else if (errno == EOPNOTSUPP)
- /* This kernel or file system does not support
- * name_to_handle_at(), hence let's see if the
- * upper fs supports it (in which case it is a
- * mount point), otherwise fallback to the
- * traditional stat() logic */
- nosupp = true;
- else
- return -errno;
- }
-
- r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH);
- if (r < 0) {
- if (errno == EOPNOTSUPP) {
- if (nosupp)
- /* Neither parent nor child do name_to_handle_at()?
- We have no choice but to fall back. */
- goto fallback_fdinfo;
- else
- /* The parent can't do name_to_handle_at() but the
- * directory we are interested in can?
- * If so, it must be a mount point. */
- return 1;
- } else
- return -errno;
- }
-
- /* The parent can do name_to_handle_at() but the
- * directory we are interested in can't? If so, it
- * must be a mount point. */
- if (nosupp)
- return 1;
-
- /* If the file handle for the directory we are
- * interested in and its parent are identical, we
- * assume this is the root directory, which is a mount
- * point. */
-
- if (h.handle.handle_bytes == h_parent.handle.handle_bytes &&
- h.handle.handle_type == h_parent.handle.handle_type &&
- memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0)
- return 1;
-
- return mount_id != mount_id_parent;
-
-fallback_fdinfo:
- r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
- if (r == -EOPNOTSUPP)
- goto fallback_fstat;
- if (r < 0)
- return r;
-
- r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent);
- if (r < 0)
- return r;
-
- if (mount_id != mount_id_parent)
- return 1;
-
- /* Hmm, so, the mount ids are the same. This leaves one
- * special case though for the root file system. For that,
- * let's see if the parent directory has the same inode as we
- * are interested in. Hence, let's also do fstat() checks now,
- * too, but avoid the st_dev comparisons, since they aren't
- * that useful on unionfs mounts. */
- check_st_dev = false;
-
-fallback_fstat:
- /* yay for fstatat() taking a different set of flags than the other
- * _at() above */
- if (flags & AT_SYMLINK_FOLLOW)
- flags &= ~AT_SYMLINK_FOLLOW;
- else
- flags |= AT_SYMLINK_NOFOLLOW;
- if (fstatat(fd, filename, &a, flags) < 0)
- return -errno;
-
- if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0)
- return -errno;
-
- /* A directory with same device and inode as its parent? Must
- * be the root directory */
- if (a.st_dev == b.st_dev &&
- a.st_ino == b.st_ino)
- return 1;
-
- return check_st_dev && (a.st_dev != b.st_dev);
-}
-
-/* flags can be AT_SYMLINK_FOLLOW or 0 */
-int path_is_mount_point(const char *t, int flags) {
- _cleanup_close_ int fd = -1;
- _cleanup_free_ char *canonical = NULL, *parent = NULL;
-
- assert(t);
-
- if (path_equal(t, "/"))
- return 1;
-
- /* we need to resolve symlinks manually, we can't just rely on
- * fd_is_mount_point() to do that for us; if we have a structure like
- * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
- * look at needs to be /usr, not /. */
- if (flags & AT_SYMLINK_FOLLOW) {
- canonical = canonicalize_file_name(t);
- if (!canonical)
- return -errno;
-
- t = canonical;
- }
-
- parent = dirname_malloc(t);
- if (!parent)
- return -ENOMEM;
-
- fd = openat(AT_FDCWD, parent, O_DIRECTORY|O_CLOEXEC|O_PATH);
- if (fd < 0)
- return -errno;
-
- return fd_is_mount_point(fd, basename(t), flags);
-}
-
-int umount_recursive(const char *prefix, int flags) {
- bool again;
- int n = 0, r;
-
- /* Try to umount everything recursively below a
- * directory. Also, take care of stacked mounts, and keep
- * unmounting them until they are gone. */
-
- do {
- _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
-
- again = false;
- r = 0;
-
- proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
- if (!proc_self_mountinfo)
- return -errno;
-
- for (;;) {
- _cleanup_free_ char *path = NULL, *p = NULL;
- 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 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;
-
- continue;
- }
-
- r = cunescape(path, UNESCAPE_RELAX, &p);
- if (r < 0)
- return r;
-
- if (!path_startswith(p, prefix))
- continue;
-
- if (umount2(p, flags) < 0) {
- r = -errno;
- continue;
- }
-
- again = true;
- n++;
-
- break;
- }
-
- } while (again);
-
- return r ? r : n;
-}
-
-static int get_mount_flags(const char *path, unsigned long *flags) {
- struct statvfs buf;
-
- if (statvfs(path, &buf) < 0)
- return -errno;
- *flags = buf.f_flag;
- return 0;
-}
-
-int bind_remount_recursive(const char *prefix, bool ro) {
- _cleanup_set_free_free_ Set *done = NULL;
- _cleanup_free_ char *cleaned = NULL;
- int r;
-
- /* Recursively remount a directory (and all its submounts)
- * read-only or read-write. If the directory is already
- * mounted, we reuse the mount and simply mark it
- * MS_BIND|MS_RDONLY (or remove the MS_RDONLY for read-write
- * operation). If it isn't we first make it one. Afterwards we
- * apply MS_BIND|MS_RDONLY (or remove MS_RDONLY) to all
- * submounts we can access, too. When mounts are stacked on
- * the same mount point we only care for each individual
- * "top-level" mount on each point, as we cannot
- * influence/access the underlying mounts anyway. We do not
- * have any effect on future submounts that might get
- * propagated, they migt be writable. This includes future
- * submounts that have been triggered via autofs. */
-
- cleaned = strdup(prefix);
- if (!cleaned)
- return -ENOMEM;
-
- path_kill_slashes(cleaned);
-
- done = set_new(&string_hash_ops);
- if (!done)
- return -ENOMEM;
-
- for (;;) {
- _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
- _cleanup_set_free_free_ Set *todo = NULL;
- bool top_autofs = false;
- char *x;
- unsigned long orig_flags;
-
- todo = set_new(&string_hash_ops);
- if (!todo)
- return -ENOMEM;
-
- proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
- if (!proc_self_mountinfo)
- return -errno;
-
- for (;;) {
- _cleanup_free_ char *path = NULL, *p = NULL, *type = NULL;
- 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 options (superblock) */
- "%*[^-]" /* (7) optional fields */
- "- " /* (8) separator */
- "%ms " /* (9) file system type */
- "%*s" /* (10) mount source */
- "%*s" /* (11) mount options (bind mount) */
- "%*[^\n]", /* some rubbish at the end */
- &path,
- &type);
- if (k != 2) {
- if (k == EOF)
- break;
-
- continue;
- }
-
- r = cunescape(path, UNESCAPE_RELAX, &p);
- if (r < 0)
- return r;
-
- /* Let's ignore autofs mounts. If they aren't
- * triggered yet, we want to avoid triggering
- * them, as we don't make any guarantees for
- * future submounts anyway. If they are
- * already triggered, then we will find
- * another entry for this. */
- if (streq(type, "autofs")) {
- top_autofs = top_autofs || path_equal(cleaned, p);
- continue;
- }
-
- if (path_startswith(p, cleaned) &&
- !set_contains(done, p)) {
-
- r = set_consume(todo, p);
- p = NULL;
-
- if (r == -EEXIST)
- continue;
- if (r < 0)
- return r;
- }
- }
-
- /* If we have no submounts to process anymore and if
- * the root is either already done, or an autofs, we
- * are done */
- if (set_isempty(todo) &&
- (top_autofs || set_contains(done, cleaned)))
- return 0;
-
- if (!set_contains(done, cleaned) &&
- !set_contains(todo, cleaned)) {
- /* The prefix directory itself is not yet a
- * mount, make it one. */
- if (mount(cleaned, cleaned, NULL, MS_BIND|MS_REC, NULL) < 0)
- return -errno;
-
- orig_flags = 0;
- (void) get_mount_flags(cleaned, &orig_flags);
- orig_flags &= ~MS_RDONLY;
-
- if (mount(NULL, prefix, NULL, orig_flags|MS_BIND|MS_REMOUNT|(ro ? MS_RDONLY : 0), NULL) < 0)
- return -errno;
-
- x = strdup(cleaned);
- if (!x)
- return -ENOMEM;
-
- r = set_consume(done, x);
- if (r < 0)
- return r;
- }
-
- while ((x = set_steal_first(todo))) {
-
- r = set_consume(done, x);
- if (r == -EEXIST || r == 0)
- continue;
- if (r < 0)
- return r;
-
- /* Deal with mount points that are obstructed by a
- * later mount */
- r = path_is_mount_point(x, 0);
- if (r == -ENOENT || r == 0)
- continue;
- if (r < 0)
- return r;
-
- /* Try to reuse the original flag set */
- orig_flags = 0;
- (void) get_mount_flags(x, &orig_flags);
- orig_flags &= ~MS_RDONLY;
-
- if (mount(NULL, x, NULL, orig_flags|MS_BIND|MS_REMOUNT|(ro ? MS_RDONLY : 0), NULL) < 0)
- return -errno;
-
- }
- }
-}
-
-int mount_move_root(const char *path) {
- assert(path);
-
- if (chdir(path) < 0)
- return -errno;
-
- if (mount(path, "/", NULL, MS_MOVE, NULL) < 0)
- return -errno;
-
- if (chroot(".") < 0)
- return -errno;
-
- if (chdir("/") < 0)
- return -errno;
-
- return 0;
-}
-
-bool fstype_is_network(const char *fstype) {
- static const char table[] =
- "afs\0"
- "cifs\0"
- "smbfs\0"
- "sshfs\0"
- "ncpfs\0"
- "ncp\0"
- "nfs\0"
- "nfs4\0"
- "gfs\0"
- "gfs2\0"
- "glusterfs\0"
- "pvfs2\0" /* OrangeFS */
- "ocfs2\0"
- ;
-
- const char *x;
-
- x = startswith(fstype, "fuse.");
- if (x)
- fstype = x;
-
- return nulstr_contains(table, fstype);
-}
-
-int repeat_unmount(const char *path, int flags) {
- bool done = false;
-
- assert(path);
-
- /* If there are multiple mounts on a mount point, this
- * removes them all */
-
- for (;;) {
- if (umount2(path, flags) < 0) {
-
- if (errno == EINVAL)
- return done;
-
- return -errno;
- }
-
- done = true;
- }
-}
-
-const char* mode_to_inaccessible_node(mode_t mode) {
- /* This function maps a node type to the correspondent inaccessible node type.
- * Character and block inaccessible devices may not be created (because major=0 and minor=0),
- * in such case we map character and block devices to the inaccessible node type socket. */
- switch(mode & S_IFMT) {
- case S_IFREG:
- return "/run/systemd/inaccessible/reg";
- case S_IFDIR:
- return "/run/systemd/inaccessible/dir";
- case S_IFCHR:
- if (access("/run/systemd/inaccessible/chr", F_OK) == 0)
- return "/run/systemd/inaccessible/chr";
- return "/run/systemd/inaccessible/sock";
- case S_IFBLK:
- if (access("/run/systemd/inaccessible/blk", F_OK) == 0)
- return "/run/systemd/inaccessible/blk";
- return "/run/systemd/inaccessible/sock";
- case S_IFIFO:
- return "/run/systemd/inaccessible/fifo";
- case S_IFSOCK:
- return "/run/systemd/inaccessible/sock";
- }
- return NULL;
-}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-03 15:21:05 +0000