-/***
- 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/>.
-***/
+/* 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/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 "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)];
+ char path[STRLEN("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
_cleanup_free_ char *fdinfo = NULL;
_cleanup_close_ int subfd = -1;
char *p;
if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */
return -EOPNOTSUPP;
if (r < 0)
- return -errno;
+ return r;
p = startswith(fdinfo, "mnt_id:");
if (!p) {
}
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;
+ _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;
* 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 (IN_SET(errno, ENOSYS, EACCES, EPERM))
- /* This kernel does not support name_to_handle_at() at all, or the syscall was blocked (maybe
- * through seccomp, because we are running inside of a container?): fall back to simpler
- * logic. */
+ 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 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'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
* 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)
+ 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;
int r;
assert(t);
+ assert((flags & ~AT_SYMLINK_FOLLOW) == 0);
if (path_equal(t, "/"))
return 1;
* /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, 0, &canonical);
+ r = chase_symlinks(t, root, CHASE_TRAIL_SLASH, &canonical);
if (r < 0)
return r;
if (fd < 0)
return -errno;
- return fd_is_mount_point(fd, basename(t), flags);
+ 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;
}
#if 0 /// UNNEEDED by elogind
if (!proc_self_mountinfo)
return -errno;
+ (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+
for (;;) {
_cleanup_free_ char *path = NULL, *p = NULL;
int k;
if (!cleaned)
return -ENOMEM;
- path_kill_slashes(cleaned);
+ path_simplify(cleaned, false);
- done = set_new(&string_hash_ops);
+ done = set_new(&path_hash_ops);
if (!done)
return -ENOMEM;
char *x;
unsigned long orig_flags;
- todo = set_new(&string_hash_ops);
+ todo = set_new(&path_hash_ops);
if (!todo)
return -ENOMEM;
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);
}
}
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"
- "lustre\0"
- ;
-
const char *x;
x = startswith(fstype, "fuse.");
if (x)
fstype = x;
- return nulstr_contains(table, fstype);
+ 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) {
- static const char table[] =
- "autofs\0"
- "bpf\0"
- "cgroup\0"
- "cgroup2\0"
- "configfs\0"
- "cpuset\0"
- "debugfs\0"
- "devpts\0"
- "devtmpfs\0"
- "efivarfs\0"
- "fusectl\0"
- "hugetlbfs\0"
- "mqueue\0"
- "proc\0"
- "pstore\0"
- "ramfs\0"
- "securityfs\0"
- "sysfs\0"
- "tmpfs\0"
- "tracefs\0"
- ;
-
- return nulstr_contains(table, 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 */
-
- static const char table[] =
- "DM_verity_hash\0"
- "iso9660\0"
- "squashfs\0"
- ;
-
- return nulstr_contains(table, fstype);
+ 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) {
- static const char table[] =
- "btrfs\0"
- "ext4\0"
- "vfat\0"
- "xfs\0"
- ;
+ /* All file systems that have a uid=/gid= mount option that fixates the owners of all files and directories,
+ * current and future. */
- return nulstr_contains(table, fstype);
+ return STR_IN_SET(fstype,
+ "adfs",
+ "fat",
+ "hfs",
+ "hpfs",
+ "iso9660",
+ "msdos",
+ "ntfs",
+ "vfat");
}
int repeat_unmount(const char *path, int flags) {
#endif // 0
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. */
+ /* 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";
}
unsigned long flags,
const char *options) {
- _cleanup_free_ char *fl = NULL;
+ _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(flags);
+ fl = mount_flags_to_string(f);
- if ((flags & MS_REMOUNT) && !what && !type)
+ if ((f & MS_REMOUNT) && !what && !type)
log_debug("Remounting %s (%s \"%s\")...",
- where, strnull(fl), strempty(options));
+ where, strnull(fl), strempty(o));
else if (!what && !type)
log_debug("Mounting %s (%s \"%s\")...",
- where, strnull(fl), strempty(options));
- else if ((flags & MS_BIND) && !type)
+ 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(options));
- else if (flags & MS_MOVE)
+ what, where, strnull(fl), strempty(o));
+ else if (f & MS_MOVE)
log_debug("Moving mount %s → %s (%s \"%s\")...",
- what, where, strnull(fl), strempty(options));
+ what, where, strnull(fl), strempty(o));
else
log_debug("Mounting %s on %s (%s \"%s\")...",
- strna(type), where, strnull(fl), strempty(options));
- if (mount(what, where, type, flags, options) < 0)
+ 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(options));
+ strna(type), where, strnull(fl), strempty(o));
return 0;
}
return NULL;
}
-
int mount_propagation_flags_from_string(const char *name, unsigned long *ret) {
if (isempty(name))
return -EINVAL;
return 0;
}
+
+#if 0 /// UNNEEDED by elogind
+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;
+}
+#endif // 0
~ianmdlvl / elogind.git / blobdiff