/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <unistd.h>
/* Include later */
#include <libmount.h>
#include "alloc-util.h"
#include "escape.h"
#include "extract-word.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.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"
#include "strv.h"
/* This is the original MAX_HANDLE_SZ definition from the kernel, when the API was introduced. We use that in place of
* any more currently defined value to future-proof things: if the size is increased in the API headers, and our code
* is recompiled then it would cease working on old kernels, as those refuse any sizes larger than this value with
* EINVAL right-away. Hence, let's disconnect ourselves from any such API changes, and stick to the original definition
* from when it was introduced. We use it as a start value only anyway (see below), and hence should be able to deal
* with large file handles anyway. */
#define ORIGINAL_MAX_HANDLE_SZ 128
int name_to_handle_at_loop(
int fd,
const char *path,
struct file_handle **ret_handle,
int *ret_mnt_id,
int flags) {
_cleanup_free_ struct file_handle *h = NULL;
size_t n = ORIGINAL_MAX_HANDLE_SZ;
/* We need to invoke name_to_handle_at() in a loop, given that it might return EOVERFLOW when the specified
* buffer is too small. Note that in contrast to what the docs might suggest, MAX_HANDLE_SZ is only good as a
* start value, it is not an upper bound on the buffer size required.
*
* This improves on raw name_to_handle_at() also in one other regard: ret_handle and ret_mnt_id can be passed
* as NULL if there's no interest in either. */
for (;;) {
int mnt_id = -1;
h = malloc0(offsetof(struct file_handle, f_handle) + n);
if (!h)
return -ENOMEM;
h->handle_bytes = n;
if (name_to_handle_at(fd, path, h, &mnt_id, flags) >= 0) {
if (ret_handle)
*ret_handle = TAKE_PTR(h);
if (ret_mnt_id)
*ret_mnt_id = mnt_id;
return 0;
}
if (errno != EOVERFLOW)
return -errno;
if (!ret_handle && ret_mnt_id && mnt_id >= 0) {
/* As it appears, name_to_handle_at() fills in mnt_id even when it returns EOVERFLOW when the
* buffer is too small, but that's undocumented. Hence, let's make use of this if it appears to
* be filled in, and the caller was interested in only the mount ID an nothing else. */
*ret_mnt_id = mnt_id;
return 0;
}
/* If name_to_handle_at() didn't increase the byte size, then this EOVERFLOW is caused by something
* else (apparently EOVERFLOW is returned for untriggered nfs4 mounts sometimes), not by the too small
* buffer. In that case propagate EOVERFLOW */
if (h->handle_bytes <= n)
return -EOVERFLOW;
/* The buffer was too small. Size the new buffer by what name_to_handle_at() returned. */
n = h->handle_bytes;
if (offsetof(struct file_handle, f_handle) + n < n) /* check for addition overflow */
return -EOVERFLOW;
h = mfree(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 r;
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) {
_cleanup_free_ struct file_handle *h = NULL, *h_parent = NULL;
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_loop(fd, filename, &h, &mount_id, flags);
if (IN_SET(r, -ENOSYS, -EACCES, -EPERM, -EOVERFLOW, -EINVAL))
/* This kernel does not support name_to_handle_at() at all (ENOSYS), or the syscall was blocked
* (EACCES/EPERM; maybe through seccomp, because we are running inside of a container?), or the mount
* point is not triggered yet (EOVERFLOW, think nfs4), or some general name_to_handle_at() flakiness
* (EINVAL): fall back to simpler logic. */
goto fallback_fdinfo;
else if (r == -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 if (r < 0)
return r;
r = name_to_handle_at_loop(fd, "", &h_parent, &mount_id_parent, AT_EMPTY_PATH);
if (r == -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 if (r < 0)
return r;
/* 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_bytes == h_parent->handle_bytes &&
h->handle_type == h_parent->handle_type &&
memcmp(h->f_handle, h_parent->f_handle, h->handle_bytes) == 0)
return 1;
return mount_id != mount_id_parent;
fallback_fdinfo:
r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
if (IN_SET(r, -EOPNOTSUPP, -EACCES, -EPERM))
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, const char *root, int flags) {
_cleanup_free_ char *canonical = NULL, *parent = NULL;
_cleanup_close_ int fd = -1;
int r;
assert(t);
assert((flags & ~AT_SYMLINK_FOLLOW) == 0);
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) {
r = chase_symlinks(t, root, CHASE_TRAIL_SLASH, &canonical);
if (r < 0)
return r;
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, last_path_component(t), flags);
}
int path_get_mnt_id(const char *path, int *ret) {
int r;
r = name_to_handle_at_loop(AT_FDCWD, path, NULL, ret, 0);
if (IN_SET(r, -EOPNOTSUPP, -ENOSYS, -EACCES, -EPERM, -EOVERFLOW, -EINVAL)) /* kernel/fs don't support this, or seccomp blocks access, or untriggered mount, or name_to_handle_at() is flaky */
return fd_fdinfo_mnt_id(AT_FDCWD, path, 0, ret);
return r;
}
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;
(void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
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 = log_debug_errno(errno, "Failed to umount %s: %m", p);
continue;
}
log_debug("Successfully unmounted %s", p);
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;
}
/* Use this function only if do you have direct access to /proc/self/mountinfo
* and need the caller to open it for you. This is the case when /proc is
* masked or not mounted. Otherwise, use bind_remount_recursive. */
int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **blacklist, FILE *proc_self_mountinfo) {
_cleanup_set_free_free_ Set *done = NULL;
_cleanup_free_ char *cleaned = NULL;
int r;
assert(proc_self_mountinfo);
/* 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.
*
* If the "blacklist" parameter is specified it may contain a list of subtrees to exclude from the
* remount operation. Note that we'll ignore the blacklist for the top-level path. */
cleaned = strdup(prefix);
if (!cleaned)
return -ENOMEM;
path_simplify(cleaned, false);
done = set_new(&path_hash_ops);
if (!done)
return -ENOMEM;
for (;;) {
_cleanup_set_free_free_ Set *todo = NULL;
bool top_autofs = false;
char *x;
unsigned long orig_flags;
todo = set_new(&path_hash_ops);
if (!todo)
return -ENOMEM;
rewind(proc_self_mountinfo);
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;
if (!path_startswith(p, cleaned))
continue;
/* Ignore this mount if it is blacklisted, but only if it isn't the top-level mount we shall
* operate on. */
if (!path_equal(cleaned, p)) {
bool blacklisted = false;
char **i;
STRV_FOREACH(i, blacklist) {
if (path_equal(*i, cleaned))
continue;
if (!path_startswith(*i, cleaned))
continue;
if (path_startswith(p, *i)) {
blacklisted = true;
log_debug("Not remounting %s, because blacklisted by %s, called for %s", p, *i, cleaned);
break;
}
}
if (blacklisted)
continue;
}
/* 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 (!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;
log_debug("Made top-level directory %s a mount point.", prefix);
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 (IN_SET(r, 0, -EEXIST))
continue;
if (r < 0)
return r;
/* Deal with mount points that are obstructed by a later mount */
r = path_is_mount_point(x, NULL, 0);
if (IN_SET(r, 0, -ENOENT))
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;
log_debug("Remounted %s read-only.", x);
}
}
}
int bind_remount_recursive(const char *prefix, bool ro, char **blacklist) {
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
if (!proc_self_mountinfo)
return -errno;
(void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
return bind_remount_recursive_with_mountinfo(prefix, ro, blacklist, proc_self_mountinfo);
}
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) {
const char *x;
x = startswith(fstype, "fuse.");
if (x)
fstype = x;
return STR_IN_SET(fstype,
"afs",
"cifs",
"smbfs",
"sshfs",
"ncpfs",
"ncp",
"nfs",
"nfs4",
"gfs",
"gfs2",
"glusterfs",
"pvfs2", /* OrangeFS */
"ocfs2",
"lustre");
}
bool fstype_is_api_vfs(const char *fstype) {
return STR_IN_SET(fstype,
"autofs",
"bpf",
"cgroup",
"cgroup2",
"configfs",
"cpuset",
"debugfs",
"devpts",
"devtmpfs",
"efivarfs",
"fusectl",
"hugetlbfs",
"mqueue",
"proc",
"pstore",
"ramfs",
"securityfs",
"sysfs",
"tmpfs",
"tracefs");
}
bool fstype_is_ro(const char *fstype) {
/* All Linux file systems that are necessarily read-only */
return STR_IN_SET(fstype,
"DM_verity_hash",
"iso9660",
"squashfs");
}
bool fstype_can_discard(const char *fstype) {
return STR_IN_SET(fstype,
"btrfs",
"ext4",
"vfat",
"xfs");
}
bool fstype_can_uid_gid(const char *fstype) {
/* All file systems that have a uid=/gid= mount option that fixates the owners of all files and directories,
* current and future. */
return STR_IN_SET(fstype,
"adfs",
"fat",
"hfs",
"hpfs",
"iso9660",
"msdos",
"ntfs",
"vfat");
}
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 a corresponding inaccessible file node. These nodes are created during
* early boot by PID 1. In some cases we lacked the privs to create the character and block devices (maybe
* because we run in an userns environment, or miss CAP_SYS_MKNOD, or run with a devices policy that excludes
* device nodes with major and minor of 0), but that's fine, in that case we use an AF_UNIX file node instead,
* which is not the same, but close enough for most uses. And most importantly, the kernel allows bind mounts
* from socket nodes to any non-directory file nodes, and that's the most important thing that matters. */
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;
}
#define FLAG(name) (flags & name ? STRINGIFY(name) "|" : "")
static char* mount_flags_to_string(long unsigned flags) {
char *x;
_cleanup_free_ char *y = NULL;
long unsigned overflow;
overflow = flags & ~(MS_RDONLY |
MS_NOSUID |
MS_NODEV |
MS_NOEXEC |
MS_SYNCHRONOUS |
MS_REMOUNT |
MS_MANDLOCK |
MS_DIRSYNC |
MS_NOATIME |
MS_NODIRATIME |
MS_BIND |
MS_MOVE |
MS_REC |
MS_SILENT |
MS_POSIXACL |
MS_UNBINDABLE |
MS_PRIVATE |
MS_SLAVE |
MS_SHARED |
MS_RELATIME |
MS_KERNMOUNT |
MS_I_VERSION |
MS_STRICTATIME |
MS_LAZYTIME);
if (flags == 0 || overflow != 0)
if (asprintf(&y, "%lx", overflow) < 0)
return NULL;
x = strjoin(FLAG(MS_RDONLY),
FLAG(MS_NOSUID),
FLAG(MS_NODEV),
FLAG(MS_NOEXEC),
FLAG(MS_SYNCHRONOUS),
FLAG(MS_REMOUNT),
FLAG(MS_MANDLOCK),
FLAG(MS_DIRSYNC),
FLAG(MS_NOATIME),
FLAG(MS_NODIRATIME),
FLAG(MS_BIND),
FLAG(MS_MOVE),
FLAG(MS_REC),
FLAG(MS_SILENT),
FLAG(MS_POSIXACL),
FLAG(MS_UNBINDABLE),
FLAG(MS_PRIVATE),
FLAG(MS_SLAVE),
FLAG(MS_SHARED),
FLAG(MS_RELATIME),
FLAG(MS_KERNMOUNT),
FLAG(MS_I_VERSION),
FLAG(MS_STRICTATIME),
FLAG(MS_LAZYTIME),
y);
if (!x)
return NULL;
if (!y)
x[strlen(x) - 1] = '\0'; /* truncate the last | */
return x;
}
int mount_verbose(
int error_log_level,
const char *what,
const char *where,
const char *type,
unsigned long flags,
const char *options) {
_cleanup_free_ char *fl = NULL, *o = NULL;
unsigned long f;
int r;
r = mount_option_mangle(options, flags, &f, &o);
if (r < 0)
return log_full_errno(error_log_level, r,
"Failed to mangle mount options %s: %m",
strempty(options));
fl = mount_flags_to_string(f);
if ((f & MS_REMOUNT) && !what && !type)
log_debug("Remounting %s (%s \"%s\")...",
where, strnull(fl), strempty(o));
else if (!what && !type)
log_debug("Mounting %s (%s \"%s\")...",
where, strnull(fl), strempty(o));
else if ((f & MS_BIND) && !type)
log_debug("Bind-mounting %s on %s (%s \"%s\")...",
what, where, strnull(fl), strempty(o));
else if (f & MS_MOVE)
log_debug("Moving mount %s → %s (%s \"%s\")...",
what, where, strnull(fl), strempty(o));
else
log_debug("Mounting %s on %s (%s \"%s\")...",
strna(type), where, strnull(fl), strempty(o));
if (mount(what, where, type, f, o) < 0)
return log_full_errno(error_log_level, errno,
"Failed to mount %s on %s (%s \"%s\"): %m",
strna(type), where, strnull(fl), strempty(o));
return 0;
}
int umount_verbose(const char *what) {
log_debug("Umounting %s...", what);
if (umount(what) < 0)
return log_error_errno(errno, "Failed to unmount %s: %m", what);
return 0;
}
const char *mount_propagation_flags_to_string(unsigned long flags) {
switch (flags & (MS_SHARED|MS_SLAVE|MS_PRIVATE)) {
case 0:
return "";
case MS_SHARED:
return "shared";
case MS_SLAVE:
return "slave";
case MS_PRIVATE:
return "private";
}
return NULL;
}
int mount_propagation_flags_from_string(const char *name, unsigned long *ret) {
if (isempty(name))
*ret = 0;
else if (streq(name, "shared"))
*ret = MS_SHARED;
else if (streq(name, "slave"))
*ret = MS_SLAVE;
else if (streq(name, "private"))
*ret = MS_PRIVATE;
else
return -EINVAL;
return 0;
}
int mount_option_mangle(
const char *options,
unsigned long mount_flags,
unsigned long *ret_mount_flags,
char **ret_remaining_options) {
const struct libmnt_optmap *map;
_cleanup_free_ char *ret = NULL;
const char *p;
int r;
/* This extracts mount flags from the mount options, and store
* non-mount-flag options to '*ret_remaining_options'.
* E.g.,
* "rw,nosuid,nodev,relatime,size=1630748k,mode=700,uid=1000,gid=1000"
* is split to MS_NOSUID|MS_NODEV|MS_RELATIME and
* "size=1630748k,mode=700,uid=1000,gid=1000".
* See more examples in test-mount-utils.c.
*
* Note that if 'options' does not contain any non-mount-flag options,
* then '*ret_remaining_options' is set to NULL instread of empty string.
* Note that this does not check validity of options stored in
* '*ret_remaining_options'.
* Note that if 'options' is NULL, then this just copies 'mount_flags'
* to '*ret_mount_flags'. */
assert(ret_mount_flags);
assert(ret_remaining_options);
map = mnt_get_builtin_optmap(MNT_LINUX_MAP);
if (!map)
return -EINVAL;
p = options;
for (;;) {
_cleanup_free_ char *word = NULL;
const struct libmnt_optmap *ent;
r = extract_first_word(&p, &word, ",", EXTRACT_QUOTES);
if (r < 0)
return r;
if (r == 0)
break;
for (ent = map; ent->name; ent++) {
/* All entries in MNT_LINUX_MAP do not take any argument.
* Thus, ent->name does not contain "=" or "[=]". */
if (!streq(word, ent->name))
continue;
if (!(ent->mask & MNT_INVERT))
mount_flags |= ent->id;
else if (mount_flags & ent->id)
mount_flags ^= ent->id;
break;
}
/* If 'word' is not a mount flag, then store it in '*ret_remaining_options'. */
if (!ent->name && !strextend_with_separator(&ret, ",", word, NULL))
return -ENOMEM;
}
*ret_mount_flags = mount_flags;
*ret_remaining_options = TAKE_PTR(ret);
return 0;
}