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Split out part of mount-util.c into mountpoint-util.c 

The idea is that anything which is related to actually manipulating mounts is
in mount-util.c, but functions for mountpoint introspection are moved to the
new file. Anything which requires libmount must be in mount-util.c.

This was supposed to be a preparation for further changes, with no functional
difference, but it results in a significant change in linkage:

$ ldd build/libnss_*.so.2
(before)
build/libnss_myhostname.so.2:
	linux-vdso.so.1 (0x00007fff77bf5000)
	librt.so.1 => /lib64/librt.so.1 (0x00007f4bbb7b2000)
	libmount.so.1 => /lib64/libmount.so.1 (0x00007f4bbb755000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f4bbb734000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f4bbb56e000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f4bbb8c1000)
	libblkid.so.1 => /lib64/libblkid.so.1 (0x00007f4bbb51b000)
	libuuid.so.1 => /lib64/libuuid.so.1 (0x00007f4bbb512000)
	libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f4bbb4e3000)
	libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007f4bbb45e000)
	libdl.so.2 => /lib64/libdl.so.2 (0x00007f4bbb458000)
build/libnss_mymachines.so.2:
	linux-vdso.so.1 (0x00007ffc19cc0000)
	librt.so.1 => /lib64/librt.so.1 (0x00007fdecb74b000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007fdecb744000)
	libmount.so.1 => /lib64/libmount.so.1 (0x00007fdecb6e7000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fdecb6c6000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fdecb500000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fdecb8a9000)
	libblkid.so.1 => /lib64/libblkid.so.1 (0x00007fdecb4ad000)
	libuuid.so.1 => /lib64/libuuid.so.1 (0x00007fdecb4a2000)
	libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fdecb475000)
	libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007fdecb3f0000)
	libdl.so.2 => /lib64/libdl.so.2 (0x00007fdecb3ea000)
build/libnss_resolve.so.2:
	linux-vdso.so.1 (0x00007ffe8ef8e000)
	librt.so.1 => /lib64/librt.so.1 (0x00007fcf314bd000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007fcf314b6000)
	libmount.so.1 => /lib64/libmount.so.1 (0x00007fcf31459000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fcf31438000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fcf31272000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fcf31615000)
	libblkid.so.1 => /lib64/libblkid.so.1 (0x00007fcf3121f000)
	libuuid.so.1 => /lib64/libuuid.so.1 (0x00007fcf31214000)
	libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fcf311e7000)
	libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007fcf31162000)
	libdl.so.2 => /lib64/libdl.so.2 (0x00007fcf3115c000)
build/libnss_systemd.so.2:
	linux-vdso.so.1 (0x00007ffda6d17000)
	librt.so.1 => /lib64/librt.so.1 (0x00007f610b83c000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007f610b835000)
	libmount.so.1 => /lib64/libmount.so.1 (0x00007f610b7d8000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f610b7b7000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f610b5f1000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f610b995000)
	libblkid.so.1 => /lib64/libblkid.so.1 (0x00007f610b59e000)
	libuuid.so.1 => /lib64/libuuid.so.1 (0x00007f610b593000)
	libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f610b566000)
	libpcre2-8.so.0 => /lib64/libpcre2-8.so.0 (0x00007f610b4e1000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00007f610b4db000)

(after)
build/libnss_myhostname.so.2:
	linux-vdso.so.1 (0x00007fff0b5e2000)
	librt.so.1 => /lib64/librt.so.1 (0x00007fde0c328000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fde0c307000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fde0c141000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fde0c435000)
build/libnss_mymachines.so.2:
	linux-vdso.so.1 (0x00007ffdc30a7000)
	librt.so.1 => /lib64/librt.so.1 (0x00007f06ecabb000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007f06ecab4000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f06eca93000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f06ec8cd000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f06ecc15000)
build/libnss_resolve.so.2:
	linux-vdso.so.1 (0x00007ffe95747000)
	librt.so.1 => /lib64/librt.so.1 (0x00007fa56a80f000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007fa56a808000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fa56a7e7000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fa56a621000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fa56a964000)
build/libnss_systemd.so.2:
	linux-vdso.so.1 (0x00007ffe67b51000)
	librt.so.1 => /lib64/librt.so.1 (0x00007ffb32113000)
	libcap.so.2 => /lib64/libcap.so.2 (0x00007ffb3210c000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007ffb320eb000)
	libc.so.6 => /lib64/libc.so.6 (0x00007ffb31f25000)
	/lib64/ld-linux-x86-64.so.2 (0x00007ffb3226a000)

I don't quite understand what is going on here, but let's not be too picky.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2018-11-29 10:24:39 +01:00
parent 192b89368e
commit 049af8ad0c
36 changed files with 762 additions and 713 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/basic/copy.c
View File

@ -24,7 +24,7 @@
#include "io-util.h"
#include "macro.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"

2
src/basic/meson.build
View File

@ -96,6 +96,8 @@ basic_sources = files('''
mkdir.h
mount-util.c
mount-util.h
mountpoint-util.c
mountpoint-util.h
nss-util.h
ordered-set.c
ordered-set.h

428
src/basic/mount-util.c
View File

@ -20,6 +20,7 @@
#include "fs-util.h"
#include "hashmap.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "set.h"
@ -27,279 +28,6 @@
#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;
_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;
}
fd = open_parent(t, O_PATH|O_CLOEXEC, 0);
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;
@ -601,86 +329,6 @@ int mount_move_root(const char *path) {
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;
@ -852,37 +500,6 @@ int umount_verbose(const char *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,
@ -951,46 +568,3 @@ int mount_option_mangle(
return 0;
}
int dev_is_devtmpfs(void) {
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
int mount_id, r;
char *e;
r = path_get_mnt_id("/dev", &mount_id);
if (r < 0)
return r;
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 *line = NULL;
int mid;
r = read_line(proc_self_mountinfo, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0)
break;
if (sscanf(line, "%i", &mid) != 1)
continue;
if (mid != mount_id)
continue;
e = strstr(line, " - ");
if (!e)
continue;
/* accept any name that starts with the currently expected type */
if (startswith(e + 3, "devtmpfs"))
return true;
}
return false;
}

26
src/basic/mount-util.h
View File

@ -1,25 +1,12 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
#include <fcntl.h>
#include <mntent.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "macro.h"
#include "missing.h"
int name_to_handle_at_loop(int fd, const char *path, struct file_handle **ret_handle, int *ret_mnt_id, int flags);
int path_get_mnt_id(const char *path, int *ret);
int fd_is_mount_point(int fd, const char *filename, int flags);
int path_is_mount_point(const char *path, const char *root, int flags);
int repeat_unmount(const char *path, int flags);
int umount_recursive(const char *target, int flags);
int bind_remount_recursive(const char *prefix, bool ro, char **blacklist);
int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **blacklist, FILE *proc_self_mountinfo);
@ -29,14 +16,6 @@ int mount_move_root(const char *path);
DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
#define _cleanup_endmntent_ _cleanup_(endmntentp)
bool fstype_is_network(const char *fstype);
bool fstype_is_api_vfs(const char *fstype);
bool fstype_is_ro(const char *fsype);
bool fstype_can_discard(const char *fstype);
bool fstype_can_uid_gid(const char *fstype);
const char* mode_to_inaccessible_node(mode_t mode);
int mount_verbose(
int error_log_level,
const char *what,
@ -46,13 +25,10 @@ int mount_verbose(
const char *options);
int umount_verbose(const char *where);
const char *mount_propagation_flags_to_string(unsigned long flags);
int mount_propagation_flags_from_string(const char *name, unsigned long *ret);
int mount_option_mangle(
const char *options,
unsigned long mount_flags,
unsigned long *ret_mount_flags,
char **ret_remaining_options);
int dev_is_devtmpfs(void);
const char* mode_to_inaccessible_node(mode_t mode);

444
src/basic/mountpoint-util.c Normal file
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@ -0,0 +1,444 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <stdio_ext.h>
#include <sys/mount.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "missing.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "stdio-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;
_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;
}
fd = open_parent(t, O_PATH|O_CLOEXEC, 0);
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;
}
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 dev_is_devtmpfs(void) {
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
int mount_id, r;
char *e;
r = path_get_mnt_id("/dev", &mount_id);
if (r < 0)
return r;
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 *line = NULL;
int mid;
r = read_line(proc_self_mountinfo, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0)
break;
if (sscanf(line, "%i", &mid) != 1)
continue;
if (mid != mount_id)
continue;
e = strstr(line, " - ");
if (!e)
continue;
/* accept any name that starts with the currently expected type */
if (startswith(e + 3, "devtmpfs"))
return true;
}
return false;
}
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;
}

24
src/basic/mountpoint-util.h Normal file
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@ -0,0 +1,24 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
#include <fcntl.h>
#include <stdbool.h>
#include <sys/types.h>
int name_to_handle_at_loop(int fd, const char *path, struct file_handle **ret_handle, int *ret_mnt_id, int flags);
int path_get_mnt_id(const char *path, int *ret);
int fd_is_mount_point(int fd, const char *filename, int flags);
int path_is_mount_point(const char *path, const char *root, int flags);
bool fstype_is_network(const char *fstype);
bool fstype_is_api_vfs(const char *fstype);
bool fstype_is_ro(const char *fsype);
bool fstype_can_discard(const char *fstype);
bool fstype_can_uid_gid(const char *fstype);
int dev_is_devtmpfs(void);
const char *mount_propagation_flags_to_string(unsigned long flags);
int mount_propagation_flags_from_string(const char *name, unsigned long *ret);

2
src/basic/rm-rf.c
View File

@ -15,7 +15,7 @@
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"

1
src/core/automount.c
View File

@ -23,6 +23,7 @@
#include "mkdir.h"
#include "mount-util.h"
#include "mount.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"

2
src/core/dbus-execute.c
View File

@ -27,7 +27,7 @@
#include "ioprio.h"
#include "journal-util.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "namespace.h"
#include "parse-util.h"
#include "path-util.h"

2
src/core/load-fragment.c
View File

@ -38,7 +38,7 @@
#include "load-fragment.h"
#include "log.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"

2
src/core/machine-id-setup.c
View File

@ -15,7 +15,7 @@
#include "machine-id-setup.h"
#include "macro.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "process-util.h"
#include "stat-util.h"

2
src/core/mount-setup.c
View File

@ -20,7 +20,7 @@
#include "missing.h"
#include "mkdir.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "set.h"
#include "smack-util.h"

2
src/core/mount.c
View File

@ -20,8 +20,8 @@
#include "manager.h"
#include "mkdir.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "mount.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"

1
src/core/namespace.c
View File

@ -20,6 +20,7 @@
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "namespace.h"
#include "path-util.h"
#include "selinux-util.h"

1
src/core/umount.c
View File

@ -25,6 +25,7 @@
#include "linux-3.13/dm-ioctl.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "process-util.h"
#include "signal-util.h"

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

@ -18,6 +18,7 @@
#include "mkdir.h"
#include "mount-setup.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "proc-cmdline.h"

2
src/gpt-auto-generator/gpt-auto-generator.c
View File

@ -23,7 +23,7 @@
#include "gpt.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "proc-cmdline.h"

2
src/libsystemd/sd-device/device-monitor.c
View File

@ -18,7 +18,7 @@
#include "hashmap.h"
#include "io-util.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "set.h"
#include "socket-util.h"
#include "string-util.h"

2
src/login/user-runtime-dir.c
View File

@ -10,7 +10,7 @@
#include "label.h"
#include "main-func.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "selinux-util.h"

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

@ -17,6 +17,7 @@
#include "fstab-util.h"
#include "main-func.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "pager.h"
#include "parse-util.h"
#include "path-util.h"

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

@ -8,6 +8,7 @@
#include "fs-util.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "nspawn-cgroup.h"
#include "nspawn-mount.h"
#include "path-util.h"

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

@ -11,6 +11,7 @@
#include "label.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "nspawn-mount.h"
#include "parse-util.h"
#include "path-util.h"

1
src/nspawn/nspawn.c
View File

@ -60,6 +60,7 @@
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "netlink-util.h"
#include "nspawn-cgroup.h"
#include "nspawn-def.h"

2
src/partition/growfs.c
View File

@ -19,7 +19,7 @@
#include "format-util.h"
#include "log.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "pretty-print.h"

2
src/shared/bus-unit-util.c
View File

@ -17,7 +17,7 @@
#include "in-addr-util.h"
#include "list.h"
#include "locale-util.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "nsflags.h"
#include "parse-util.h"
#include "path-util.h"

2
src/shared/bus-util.c
View File

@ -28,7 +28,7 @@
#include "escape.h"
#include "fd-util.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "nsflags.h"
#include "parse-util.h"
#include "proc-cmdline.h"

2
src/shared/condition.c
View File

@ -30,7 +30,7 @@
#include "ima-util.h"
#include "list.h"
#include "macro.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "proc-cmdline.h"

1
src/shared/dissect-image.c
View File

@ -26,6 +26,7 @@
#include "id128-util.h"
#include "linux-3.13/dm-ioctl.h"
#include "missing.h"
#include "mountpoint-util.h"
#include "mount-util.h"
#include "os-util.h"
#include "path-util.h"

1
src/shared/switch-root.c
View File

@ -16,6 +16,7 @@
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stdio-util.h"

4
src/test/meson.build
View File

@ -213,6 +213,10 @@ tests += [
[],
[]],
[['src/test/test-mountpoint-util.c'],
[],
[]],
[['src/test/test-exec-util.c'],
[],
[]],

244
src/test/test-mount-util.c
View File

@ -3,243 +3,10 @@
#include <sys/mount.h>
#include "alloc-util.h"
#include "def.h"
#include "fd-util.h"
#include "fileio.h"
#include "hashmap.h"
#include "log.h"
#include "log.h"
#include "mount-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"
#include "tests.h"
static void test_mount_propagation_flags(const char *name, int ret, unsigned long expected) {
long unsigned flags;
assert_se(mount_propagation_flags_from_string(name, &flags) == ret);
if (ret >= 0) {
const char *c;
assert_se(flags == expected);
c = mount_propagation_flags_to_string(flags);
if (isempty(name))
assert_se(isempty(c));
else
assert_se(streq(c, name));
}
}
static void test_mnt_id(void) {
_cleanup_fclose_ FILE *f = NULL;
Hashmap *h;
Iterator i;
char *p;
void *k;
int r;
assert_se(f = fopen("/proc/self/mountinfo", "re"));
assert_se(h = hashmap_new(&trivial_hash_ops));
for (;;) {
_cleanup_free_ char *line = NULL, *path = NULL;
int mnt_id;
r = read_line(f, LONG_LINE_MAX, &line);
if (r == 0)
break;
assert_se(r > 0);
assert_se(sscanf(line, "%i %*s %*s %*s %ms", &mnt_id, &path) == 2);
assert_se(hashmap_put(h, INT_TO_PTR(mnt_id), path) >= 0);
path = NULL;
}
HASHMAP_FOREACH_KEY(p, k, h, i) {
int mnt_id = PTR_TO_INT(k), mnt_id2;
r = path_get_mnt_id(p, &mnt_id2);
if (r < 0) {
log_debug_errno(r, "Failed to get the mnt id of %s: %m\n", p);
continue;
}
log_debug("mnt id of %s is %i\n", p, mnt_id2);
if (mnt_id == mnt_id2)
continue;
/* The ids don't match? If so, then there are two mounts on the same path, let's check if that's really
* the case */
assert_se(path_equal_ptr(hashmap_get(h, INT_TO_PTR(mnt_id2)), p));
}
hashmap_free_free(h);
}
static void test_path_is_mount_point(void) {
int fd;
char tmp_dir[] = "/tmp/test-path-is-mount-point-XXXXXX";
_cleanup_free_ char *file1 = NULL, *file2 = NULL, *link1 = NULL, *link2 = NULL;
_cleanup_free_ char *dir1 = NULL, *dir1file = NULL, *dirlink1 = NULL, *dirlink1file = NULL;
_cleanup_free_ char *dir2 = NULL, *dir2file = NULL;
assert_se(path_is_mount_point("/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/", NULL, 0) > 0);
assert_se(path_is_mount_point("//", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("//", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/proc", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/proc/", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc/1", NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point("/proc/1", NULL, 0) == 0);
assert_se(path_is_mount_point("/proc/1/", NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point("/proc/1/", NULL, 0) == 0);
assert_se(path_is_mount_point("/sys", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/sys", NULL, 0) > 0);
assert_se(path_is_mount_point("/sys/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/sys/", NULL, 0) > 0);
/* we'll create a hierarchy of different kinds of dir/file/link
* layouts:
*
* <tmp>/file1, <tmp>/file2
* <tmp>/link1 -> file1, <tmp>/link2 -> file2
* <tmp>/dir1/
* <tmp>/dir1/file
* <tmp>/dirlink1 -> dir1
* <tmp>/dirlink1file -> dirlink1/file
* <tmp>/dir2/
* <tmp>/dir2/file
*/
/* file mountpoints */
assert_se(mkdtemp(tmp_dir) != NULL);
file1 = path_join(NULL, tmp_dir, "file1");
assert_se(file1);
file2 = path_join(NULL, tmp_dir, "file2");
assert_se(file2);
fd = open(file1, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
fd = open(file2, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
link1 = path_join(NULL, tmp_dir, "link1");
assert_se(link1);
assert_se(symlink("file1", link1) == 0);
link2 = path_join(NULL, tmp_dir, "link2");
assert_se(link1);
assert_se(symlink("file2", link2) == 0);
assert_se(path_is_mount_point(file1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(file1, NULL, 0) == 0);
assert_se(path_is_mount_point(link1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(link1, NULL, 0) == 0);
/* directory mountpoints */
dir1 = path_join(NULL, tmp_dir, "dir1");
assert_se(dir1);
assert_se(mkdir(dir1, 0755) == 0);
dirlink1 = path_join(NULL, tmp_dir, "dirlink1");
assert_se(dirlink1);
assert_se(symlink("dir1", dirlink1) == 0);
dirlink1file = path_join(NULL, tmp_dir, "dirlink1file");
assert_se(dirlink1file);
assert_se(symlink("dirlink1/file", dirlink1file) == 0);
dir2 = path_join(NULL, tmp_dir, "dir2");
assert_se(dir2);
assert_se(mkdir(dir2, 0755) == 0);
assert_se(path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1, NULL, 0) == 0);
assert_se(path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1, NULL, 0) == 0);
/* file in subdirectory mountpoints */
dir1file = path_join(NULL, dir1, "file");
assert_se(dir1file);
fd = open(dir1file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(path_is_mount_point(dir1file, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1file, NULL, 0) == 0);
assert_se(path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1file, NULL, 0) == 0);
/* these tests will only work as root */
if (mount(file1, file2, NULL, MS_BIND, NULL) >= 0) {
int rf, rt, rdf, rdt, rlf, rlt, rl1f, rl1t;
const char *file2d;
/* files */
/* capture results in vars, to avoid dangling mounts on failure */
log_info("%s: %s", __func__, file2);
rf = path_is_mount_point(file2, NULL, 0);
rt = path_is_mount_point(file2, NULL, AT_SYMLINK_FOLLOW);
file2d = strjoina(file2, "/");
log_info("%s: %s", __func__, file2d);
rdf = path_is_mount_point(file2d, NULL, 0);
rdt = path_is_mount_point(file2d, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, link2);
rlf = path_is_mount_point(link2, NULL, 0);
rlt = path_is_mount_point(link2, NULL, AT_SYMLINK_FOLLOW);
assert_se(umount(file2) == 0);
assert_se(rf == 1);
assert_se(rt == 1);
assert_se(rdf == -ENOTDIR);
assert_se(rdt == -ENOTDIR);
assert_se(rlf == 0);
assert_se(rlt == 1);
/* dirs */
dir2file = path_join(NULL, dir2, "file");
assert_se(dir2file);
fd = open(dir2file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(mount(dir2, dir1, NULL, MS_BIND, NULL) >= 0);
log_info("%s: %s", __func__, dir1);
rf = path_is_mount_point(dir1, NULL, 0);
rt = path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, dirlink1);
rlf = path_is_mount_point(dirlink1, NULL, 0);
rlt = path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, dirlink1file);
/* its parent is a mount point, but not /file itself */
rl1f = path_is_mount_point(dirlink1file, NULL, 0);
rl1t = path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW);
assert_se(umount(dir1) == 0);
assert_se(rf == 1);
assert_se(rt == 1);
assert_se(rlf == 0);
assert_se(rlt == 1);
assert_se(rl1f == 0);
assert_se(rl1t == 0);
} else
printf("Skipping bind mount file test: %m\n");
assert_se(rm_rf(tmp_dir, REMOVE_ROOT|REMOVE_PHYSICAL) == 0);
}
static void test_mount_option_mangle(void) {
char *opts = NULL;
unsigned long f;
@ -295,19 +62,8 @@ static void test_mount_option_mangle(void) {
}
int main(int argc, char *argv[]) {
test_setup_logging(LOG_DEBUG);
test_mount_propagation_flags("shared", 0, MS_SHARED);
test_mount_propagation_flags("slave", 0, MS_SLAVE);
test_mount_propagation_flags("private", 0, MS_PRIVATE);
test_mount_propagation_flags(NULL, 0, 0);
test_mount_propagation_flags("", 0, 0);
test_mount_propagation_flags("xxxx", -EINVAL, 0);
test_mount_propagation_flags(" ", -EINVAL, 0);
test_mnt_id();
test_path_is_mount_point();
test_mount_option_mangle();
return 0;

258
src/test/test-mountpoint-util.c Normal file
View File

@ -0,0 +1,258 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sys/mount.h>
#include "alloc-util.h"
#include "def.h"
#include "fd-util.h"
#include "fileio.h"
#include "hashmap.h"
#include "log.h"
#include "log.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"
#include "tests.h"
static void test_mount_propagation_flags(const char *name, int ret, unsigned long expected) {
long unsigned flags;
assert_se(mount_propagation_flags_from_string(name, &flags) == ret);
if (ret >= 0) {
const char *c;
assert_se(flags == expected);
c = mount_propagation_flags_to_string(flags);
if (isempty(name))
assert_se(isempty(c));
else
assert_se(streq(c, name));
}
}
static void test_mnt_id(void) {
_cleanup_fclose_ FILE *f = NULL;
Hashmap *h;
Iterator i;
char *p;
void *k;
int r;
assert_se(f = fopen("/proc/self/mountinfo", "re"));
assert_se(h = hashmap_new(&trivial_hash_ops));
for (;;) {
_cleanup_free_ char *line = NULL, *path = NULL;
int mnt_id;
r = read_line(f, LONG_LINE_MAX, &line);
if (r == 0)
break;
assert_se(r > 0);
assert_se(sscanf(line, "%i %*s %*s %*s %ms", &mnt_id, &path) == 2);
assert_se(hashmap_put(h, INT_TO_PTR(mnt_id), path) >= 0);
path = NULL;
}
HASHMAP_FOREACH_KEY(p, k, h, i) {
int mnt_id = PTR_TO_INT(k), mnt_id2;
r = path_get_mnt_id(p, &mnt_id2);
if (r < 0) {
log_debug_errno(r, "Failed to get the mnt id of %s: %m\n", p);
continue;
}
log_debug("mnt id of %s is %i\n", p, mnt_id2);
if (mnt_id == mnt_id2)
continue;
/* The ids don't match? If so, then there are two mounts on the same path, let's check if that's really
* the case */
assert_se(path_equal_ptr(hashmap_get(h, INT_TO_PTR(mnt_id2)), p));
}
hashmap_free_free(h);
}
static void test_path_is_mount_point(void) {
int fd;
char tmp_dir[] = "/tmp/test-path-is-mount-point-XXXXXX";
_cleanup_free_ char *file1 = NULL, *file2 = NULL, *link1 = NULL, *link2 = NULL;
_cleanup_free_ char *dir1 = NULL, *dir1file = NULL, *dirlink1 = NULL, *dirlink1file = NULL;
_cleanup_free_ char *dir2 = NULL, *dir2file = NULL;
assert_se(path_is_mount_point("/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/", NULL, 0) > 0);
assert_se(path_is_mount_point("//", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("//", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/proc", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/proc/", NULL, 0) > 0);
assert_se(path_is_mount_point("/proc/1", NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point("/proc/1", NULL, 0) == 0);
assert_se(path_is_mount_point("/proc/1/", NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point("/proc/1/", NULL, 0) == 0);
assert_se(path_is_mount_point("/sys", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/sys", NULL, 0) > 0);
assert_se(path_is_mount_point("/sys/", NULL, AT_SYMLINK_FOLLOW) > 0);
assert_se(path_is_mount_point("/sys/", NULL, 0) > 0);
/* we'll create a hierarchy of different kinds of dir/file/link
* layouts:
*
* <tmp>/file1, <tmp>/file2
* <tmp>/link1 -> file1, <tmp>/link2 -> file2
* <tmp>/dir1/
* <tmp>/dir1/file
* <tmp>/dirlink1 -> dir1
* <tmp>/dirlink1file -> dirlink1/file
* <tmp>/dir2/
* <tmp>/dir2/file
*/
/* file mountpoints */
assert_se(mkdtemp(tmp_dir) != NULL);
file1 = path_join(NULL, tmp_dir, "file1");
assert_se(file1);
file2 = path_join(NULL, tmp_dir, "file2");
assert_se(file2);
fd = open(file1, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
fd = open(file2, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
link1 = path_join(NULL, tmp_dir, "link1");
assert_se(link1);
assert_se(symlink("file1", link1) == 0);
link2 = path_join(NULL, tmp_dir, "link2");
assert_se(link1);
assert_se(symlink("file2", link2) == 0);
assert_se(path_is_mount_point(file1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(file1, NULL, 0) == 0);
assert_se(path_is_mount_point(link1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(link1, NULL, 0) == 0);
/* directory mountpoints */
dir1 = path_join(NULL, tmp_dir, "dir1");
assert_se(dir1);
assert_se(mkdir(dir1, 0755) == 0);
dirlink1 = path_join(NULL, tmp_dir, "dirlink1");
assert_se(dirlink1);
assert_se(symlink("dir1", dirlink1) == 0);
dirlink1file = path_join(NULL, tmp_dir, "dirlink1file");
assert_se(dirlink1file);
assert_se(symlink("dirlink1/file", dirlink1file) == 0);
dir2 = path_join(NULL, tmp_dir, "dir2");
assert_se(dir2);
assert_se(mkdir(dir2, 0755) == 0);
assert_se(path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1, NULL, 0) == 0);
assert_se(path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1, NULL, 0) == 0);
/* file in subdirectory mountpoints */
dir1file = path_join(NULL, dir1, "file");
assert_se(dir1file);
fd = open(dir1file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(path_is_mount_point(dir1file, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dir1file, NULL, 0) == 0);
assert_se(path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW) == 0);
assert_se(path_is_mount_point(dirlink1file, NULL, 0) == 0);
/* these tests will only work as root */
if (mount(file1, file2, NULL, MS_BIND, NULL) >= 0) {
int rf, rt, rdf, rdt, rlf, rlt, rl1f, rl1t;
const char *file2d;
/* files */
/* capture results in vars, to avoid dangling mounts on failure */
log_info("%s: %s", __func__, file2);
rf = path_is_mount_point(file2, NULL, 0);
rt = path_is_mount_point(file2, NULL, AT_SYMLINK_FOLLOW);
file2d = strjoina(file2, "/");
log_info("%s: %s", __func__, file2d);
rdf = path_is_mount_point(file2d, NULL, 0);
rdt = path_is_mount_point(file2d, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, link2);
rlf = path_is_mount_point(link2, NULL, 0);
rlt = path_is_mount_point(link2, NULL, AT_SYMLINK_FOLLOW);
assert_se(umount(file2) == 0);
assert_se(rf == 1);
assert_se(rt == 1);
assert_se(rdf == -ENOTDIR);
assert_se(rdt == -ENOTDIR);
assert_se(rlf == 0);
assert_se(rlt == 1);
/* dirs */
dir2file = path_join(NULL, dir2, "file");
assert_se(dir2file);
fd = open(dir2file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
assert_se(fd > 0);
close(fd);
assert_se(mount(dir2, dir1, NULL, MS_BIND, NULL) >= 0);
log_info("%s: %s", __func__, dir1);
rf = path_is_mount_point(dir1, NULL, 0);
rt = path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, dirlink1);
rlf = path_is_mount_point(dirlink1, NULL, 0);
rlt = path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW);
log_info("%s: %s", __func__, dirlink1file);
/* its parent is a mount point, but not /file itself */
rl1f = path_is_mount_point(dirlink1file, NULL, 0);
rl1t = path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW);
assert_se(umount(dir1) == 0);
assert_se(rf == 1);
assert_se(rt == 1);
assert_se(rlf == 0);
assert_se(rlt == 1);
assert_se(rl1f == 0);
assert_se(rl1t == 0);
} else
printf("Skipping bind mount file test: %m\n");
assert_se(rm_rf(tmp_dir, REMOVE_ROOT|REMOVE_PHYSICAL) == 0);
}
int main(int argc, char *argv[]) {
test_setup_logging(LOG_DEBUG);
test_mount_propagation_flags("shared", 0, MS_SHARED);
test_mount_propagation_flags("slave", 0, MS_SLAVE);
test_mount_propagation_flags("private", 0, MS_PRIVATE);
test_mount_propagation_flags(NULL, 0, 0);
test_mount_propagation_flags("", 0, 0);
test_mount_propagation_flags("xxxx", -EINVAL, 0);
test_mount_propagation_flags(" ", -EINVAL, 0);
test_mnt_id();
test_path_is_mount_point();
return 0;
}

2
src/test/test-path-util.c
View File

@ -6,7 +6,7 @@
#include "alloc-util.h"
#include "fd-util.h"
#include "macro.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"

2
src/test/test-stat-util.c
View File

@ -9,7 +9,7 @@
#include "fileio.h"
#include "macro.h"
#include "missing.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "stat-util.h"
static void test_files_same(void) {

2
src/tmpfiles/tmpfiles.c
View File

@ -41,7 +41,7 @@
#include "macro.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "pager.h"
#include "parse-util.h"
#include "path-lookup.h"

1
src/volatile-root/volatile-root.c
View File

@ -7,6 +7,7 @@
#include "main-func.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "stat-util.h"
#include "string-util.h"