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util-lib: move mount related utility calls to mount-util.[ch]

This commit is contained in:
Lennart Poettering 2015-10-26 18:44:13 +01:00
parent 6550203eb4
commit 4349cd7c1d
24 changed files with 553 additions and 475 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile.am
View File

@ -791,6 +791,8 @@ libbasic_la_SOURCES = \
src/basic/parse-util.h \
src/basic/user-util.c \
src/basic/user-util.h \
src/basic/mount-util.c \
src/basic/mount-util.h \
src/basic/hexdecoct.c \
src/basic/hexdecoct.h \
src/basic/extract-word.c \

483
src/basic/mount-util.c Normal file
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@ -0,0 +1,483 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 <string.h>
#include <sys/mount.h>
#include <sys/statvfs.h>
#include "escape.h"
#include "fd-util.h"
#include "fileio.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "set.h"
#include "string-util.h"
#include "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_RDONLY|O_CLOEXEC|O_NOCTTY|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 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_RDONLY|O_NONBLOCK|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;
/* Try to reuse the original flag set, but
* don't care for errors, in case of
* obstructed mounts */
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) {
/* Deal with mount points that are
* obstructed by a later mount */
if (errno != ENOENT)
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;
}

36
src/basic/mount-util.h Normal file
View File

@ -0,0 +1,36 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
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 <stdbool.h>
#include <mntent.h>
int fd_is_mount_point(int fd, const char *filename, int flags);
int path_is_mount_point(const char *path, int flags);
int umount_recursive(const char *target, int flags);
int bind_remount_recursive(const char *prefix, bool ro);
int mount_move_root(const char *path);
DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
#define _cleanup_endmntent_ _cleanup_(endmntentp)

199
src/basic/path-util.c
View File

@ -454,205 +454,6 @@ char* path_join(const char *root, const char *path, const char *rest) {
NULL);
}
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_RDONLY|O_CLOEXEC|O_NOCTTY|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 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_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_PATH);
if (fd < 0)
return -errno;
return fd_is_mount_point(fd, basename(t), flags);
}
int path_is_read_only_fs(const char *path) {
struct statvfs st;

2
src/basic/path-util.h
View File

@ -52,8 +52,6 @@ int path_strv_make_absolute_cwd(char **l);
char** path_strv_resolve(char **l, const char *prefix);
char** path_strv_resolve_uniq(char **l, const char *prefix);
int fd_is_mount_point(int fd, const char *filename, int flags);
int path_is_mount_point(const char *path, int flags);
int path_is_read_only_fs(const char *path);
int path_is_os_tree(const char *path);

1
src/basic/rm-rf.c
View File

@ -21,6 +21,7 @@
#include "btrfs-util.h"
#include "fd-util.h"
#include "mount-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"

249
src/basic/util.c
View File

@ -2137,237 +2137,6 @@ int update_reboot_param_file(const char *param) {
return 0;
}
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;
/* Try to reuse the original flag set, but
* don't care for errors, in case of
* obstructed mounts */
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) {
/* Deal with mount points that are
* obstructed by a later mount */
if (errno != ENOENT)
return -errno;
}
}
}
}
int take_password_lock(const char *root) {
struct flock flock = {
@ -2710,24 +2479,6 @@ int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char
return 0;
}
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;
}
int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) {
char *v;
size_t l;

10
src/basic/util.h
View File

@ -27,7 +27,6 @@
#include <inttypes.h>
#include <limits.h>
#include <locale.h>
#include <mntent.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
@ -279,12 +278,9 @@ static inline void umaskp(mode_t *u) {
umask(*u);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
#define _cleanup_free_ _cleanup_(freep)
#define _cleanup_umask_ _cleanup_(umaskp)
#define _cleanup_globfree_ _cleanup_(globfree)
#define _cleanup_endmntent_ _cleanup_(endmntentp)
_malloc_ _alloc_(1, 2) static inline void *malloc_multiply(size_t a, size_t b) {
if (_unlikely_(b != 0 && a > ((size_t) -1) / b))
@ -525,10 +521,6 @@ union file_handle_union {
int update_reboot_param_file(const char *param);
int umount_recursive(const char *target, int flags);
int bind_remount_recursive(const char *prefix, bool ro);
int take_password_lock(const char *root);
int is_symlink(const char *path);
@ -568,8 +560,6 @@ int syslog_parse_priority(const char **p, int *priority, bool with_facility);
int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath);
int mount_move_root(const char *path);
int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink);
int fgetxattr_malloc(int fd, const char *name, char **value);

1
src/core/automount.c
View File

@ -39,6 +39,7 @@
#include "io-util.h"
#include "label.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mount.h"
#include "parse-util.h"
#include "path-util.h"

3
src/core/machine-id-setup.c
View File

@ -31,12 +31,13 @@
#include "fd-util.h"
#include "fileio.h"
#include "hexdecoct.h"
#include "io-util.h"
#include "log.h"
#include "machine-id-setup.h"
#include "macro.h"
#include "mkdir.h"
#include "hexdecoct.h"
#include "mount-util.h"
#include "path-util.h"
#include "process-util.h"
#include "string-util.h"

23
src/core/mount-setup.c
View File

@ -25,22 +25,23 @@
#include <unistd.h>
#include <ftw.h>
#include "mount-setup.h"
#include "dev-setup.h"
#include "bus-util.h"
#include "cgroup-util.h"
#include "dev-setup.h"
#include "efivars.h"
#include "label.h"
#include "log.h"
#include "macro.h"
#include "util.h"
#include "label.h"
#include "set.h"
#include "strv.h"
#include "mkdir.h"
#include "path-util.h"
#include "missing.h"
#include "virt.h"
#include "efivars.h"
#include "mkdir.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "path-util.h"
#include "set.h"
#include "smack-util.h"
#include "cgroup-util.h"
#include "strv.h"
#include "util.h"
#include "virt.h"
typedef enum MountMode {
MNT_NONE = 0,

1
src/core/namespace.c
View File

@ -33,6 +33,7 @@
#include "loopback-setup.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "namespace.h"
#include "path-util.h"
#include "selinux-util.h"

1
src/cryptsetup/cryptsetup.c
View File

@ -32,6 +32,7 @@
#include "escape.h"
#include "fileio.h"
#include "log.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "string-util.h"

1
src/fstab-generator/fstab-generator.c
View File

@ -32,6 +32,7 @@
#include "log.h"
#include "mkdir.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "special.h"

1
src/gpt-auto-generator/gpt-auto-generator.c
View File

@ -37,6 +37,7 @@
#include "gpt.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "special.h"

1
src/login/logind-user.c
View File

@ -36,6 +36,7 @@
#include "label.h"
#include "logind-user.h"
#include "mkdir.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "rm-rf.h"

1
src/nspawn/nspawn-mount.c
View File

@ -26,6 +26,7 @@
#include "escape.h"
#include "label.h"
#include "mkdir.h"
#include "mount-util.h"
#include "nspawn-mount.h"
#include "parse-util.h"
#include "path-util.h"

1
src/nspawn/nspawn.c
View File

@ -69,6 +69,7 @@
#include "macro.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "netlink-util.h"
#include "nspawn-cgroup.h"
#include "nspawn-expose-ports.h"

7
src/remount-fs/remount-fs.c
View File

@ -26,12 +26,13 @@
#include <sys/wait.h>
#include <mntent.h>
#include "exit-status.h"
#include "log.h"
#include "util.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "path-util.h"
#include "signal-util.h"
#include "mount-setup.h"
#include "exit-status.h"
#include "util.h"
/* Goes through /etc/fstab and remounts all API file systems, applying
* options that are in /etc/fstab that systemd might not have

1
src/shared/condition.c
View File

@ -36,6 +36,7 @@
#include "fd-util.h"
#include "hostname-util.h"
#include "ima-util.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "selinux-util.h"

1
src/shared/fstab-util.c
View File

@ -21,6 +21,7 @@
#include "device-nodes.h"
#include "fstab-util.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "string-util.h"

1
src/shared/generator.c
View File

@ -28,6 +28,7 @@
#include "fstab-util.h"
#include "generator.h"
#include "mkdir.h"
#include "mount-util.h"
#include "path-util.h"
#include "special.h"
#include "string-util.h"

1
src/shared/machine-pool.c
View File

@ -36,6 +36,7 @@
#include "signal-util.h"
#include "string-util.h"
#include "util.h"
#include "mount-util.h"
#define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
#define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)

1
src/test/test-path-util.c
View File

@ -25,6 +25,7 @@
#include "fd-util.h"
#include "macro.h"
#include "mount-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"