13665439908

Committed 04 Mar 2025 09:54PM UTC coverage: 71.855% (+0.04%) from 71.819%

Build # 13665439908

Build Type

push

github

Committed by

poettering

Commit Message

dirent-util: add several assertions in posix_getdents()

Follow-up for e86a492ff.

Coverage Stats

4 of 4 new or added lines in 1 file covered. (100.0%)

8029 existing lines in 84 files now uncovered.

294783 of 410245 relevant lines covered (71.86%)

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92.61

/src/basic/stat-util.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <sys/statvfs.h>
#include <sys/types.h>
#include <unistd.h>

#include "alloc-util.h"
#include "chase.h"
#include "dirent-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "filesystems.h"
#include "fs-util.h"
#include "hash-funcs.h"
#include "macro.h"
#include "missing_fs.h"
#include "missing_magic.h"
#include "mountpoint-util.h"
#include "nulstr-util.h"
#include "parse-util.h"
#include "stat-util.h"
#include "string-util.h"

static int verify_stat_at(
                int fd,
                const char *path,
                bool follow,
                int (*verify_func)(const struct stat *st),
                bool verify) {

        struct stat st;
        int r;

        assert(fd >= 0 || fd == AT_FDCWD);
        assert(!isempty(path) || !follow);
        assert(verify_func);

        if (fstatat(fd, strempty(path), &st,
                    (isempty(path) ? AT_EMPTY_PATH : 0) | (follow ? 0 : AT_SYMLINK_NOFOLLOW)) < 0)
                return -errno;

        r = verify_func(&st);
        return verify ? r : r >= 0;
}

int stat_verify_regular(const struct stat *st) {
        assert(st);

        /* Checks whether the specified stat() structure refers to a regular file. If not returns an
         * appropriate error code. */

        if (S_ISDIR(st->st_mode))
                return -EISDIR;

        if (S_ISLNK(st->st_mode))
                return -ELOOP;

        if (!S_ISREG(st->st_mode))
                return -EBADFD;

        return 0;
}

int verify_regular_at(int fd, const char *path, bool follow) {
        return verify_stat_at(fd, path, follow, stat_verify_regular, true);
}

int fd_verify_regular(int fd) {
        assert(fd >= 0);
        return verify_regular_at(fd, NULL, false);
}

int stat_verify_directory(const struct stat *st) {
        assert(st);

        if (S_ISLNK(st->st_mode))
                return -ELOOP;

        if (!S_ISDIR(st->st_mode))
                return -ENOTDIR;

        return 0;
}

int fd_verify_directory(int fd) {
        assert(fd >= 0);
        return verify_stat_at(fd, NULL, false, stat_verify_directory, true);
}

int is_dir_at(int fd, const char *path, bool follow) {
        return verify_stat_at(fd, path, follow, stat_verify_directory, false);
}

int is_dir(const char *path, bool follow) {
        assert(!isempty(path));
        return is_dir_at(AT_FDCWD, path, follow);
}

int stat_verify_symlink(const struct stat *st) {
        assert(st);

        if (S_ISDIR(st->st_mode))
                return -EISDIR;

        if (!S_ISLNK(st->st_mode))
                return -ENOLINK;

        return 0;
}

int is_symlink(const char *path) {
        assert(!isempty(path));
        return verify_stat_at(AT_FDCWD, path, false, stat_verify_symlink, false);
}

int stat_verify_linked(const struct stat *st) {
        assert(st);

        if (st->st_nlink <= 0)
                return -EIDRM; /* recognizable error. */

        return 0;
}

int fd_verify_linked(int fd) {
        assert(fd >= 0);
        return verify_stat_at(fd, NULL, false, stat_verify_linked, true);
}

int stat_verify_device_node(const struct stat *st) {
        assert(st);

        if (S_ISLNK(st->st_mode))
                return -ELOOP;

        if (S_ISDIR(st->st_mode))
                return -EISDIR;

        if (!S_ISBLK(st->st_mode) && !S_ISCHR(st->st_mode))
                return -ENOTTY;

        return 0;
}

int is_device_node(const char *path) {
        assert(!isempty(path));
        return verify_stat_at(AT_FDCWD, path, false, stat_verify_device_node, false);
}

int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup) {
        _cleanup_close_ int fd = -EBADF;
        struct dirent *buf;
        size_t m;

        fd = xopenat(dir_fd, path, O_DIRECTORY|O_CLOEXEC);
        if (fd < 0)
                return fd;

        /* Allocate space for at least 3 full dirents, since every dir has at least two entries ("."  +
         * ".."), and only once we have seen if there's a third we know whether the dir is empty or not. If
         * 'ignore_hidden_or_backup' is true we'll allocate a bit more, since we might skip over a bunch of
         * entries that we end up ignoring. */
        m = (ignore_hidden_or_backup ? 16 : 3) * DIRENT_SIZE_MAX;
        buf = alloca(m);

        for (;;) {
                struct dirent *de;
                ssize_t n;

                n = posix_getdents(fd, buf, m, /* flags = */ 0);
                if (n < 0)
                        return -errno;
                if (n == 0)
                        break;

                assert((size_t) n <= m);
                msan_unpoison(buf, n);

                FOREACH_DIRENT_IN_BUFFER(de, buf, n)
                        if (!(ignore_hidden_or_backup ? hidden_or_backup_file(de->d_name) : dot_or_dot_dot(de->d_name)))
                                return 0;
        }

        return 1;
}

bool null_or_empty(struct stat *st) {
        assert(st);

        if (S_ISREG(st->st_mode) && st->st_size <= 0)
                return true;

        /* We don't want to hardcode the major/minor of /dev/null, hence we do a simpler "is this a character
         * device node?" check. */

        if (S_ISCHR(st->st_mode))
                return true;

        return false;
}

int null_or_empty_path_with_root(const char *fn, const char *root) {
        struct stat st;
        int r;

        assert(fn);

        /* A symlink to /dev/null or an empty file?
         * When looking under root_dir, we can't expect /dev/ to be mounted,
         * so let's see if the path is a (possibly dangling) symlink to /dev/null. */

        if (path_equal(path_startswith(fn, root ?: "/"), "dev/null"))
                return true;

        r = chase_and_stat(fn, root, CHASE_PREFIX_ROOT, NULL, &st);
        if (r < 0)
                return r;

        return null_or_empty(&st);
}

int fd_is_read_only_fs(int fd) {
        struct statvfs st;

        assert(fd >= 0);

        if (fstatvfs(fd, &st) < 0)
                return -errno;

        if (st.f_flag & ST_RDONLY)
                return true;

        /* On NFS, fstatvfs() might not reflect whether we can actually write to the remote share. Let's try
         * again with access(W_OK) which is more reliable, at least sometimes. */
        if (access_fd(fd, W_OK) == -EROFS)
                return true;

        return false;
}

int path_is_read_only_fs(const char *path) {
        _cleanup_close_ int fd = -EBADF;

        assert(path);

        fd = open(path, O_CLOEXEC | O_PATH);
        if (fd < 0)
                return -errno;

        return fd_is_read_only_fs(fd);
}

int inode_same_at(int fda, const char *filea, int fdb, const char *fileb, int flags) {
        struct stat sta, stb;
        int r;

        assert(fda >= 0 || fda == AT_FDCWD);
        assert(fdb >= 0 || fdb == AT_FDCWD);
        assert((flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW|AT_NO_AUTOMOUNT)) == 0);

        /* Refuse an unset filea or fileb early unless AT_EMPTY_PATH is set */
        if ((isempty(filea) || isempty(fileb)) && !FLAGS_SET(flags, AT_EMPTY_PATH))
                return -EINVAL;

        /* Shortcut: comparing the same fd with itself means we can return true */
        if (fda >= 0 && fda == fdb && isempty(filea) && isempty(fileb) && FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW))
                return true;

        _cleanup_close_ int pin_a = -EBADF, pin_b = -EBADF;
        if (!FLAGS_SET(flags, AT_NO_AUTOMOUNT)) {
                /* Let's try to use the name_to_handle_at() AT_HANDLE_FID API to identify identical
                 * inodes. We have to issue multiple calls on the same file for that (first, to acquire the
                 * FID, and then to check if .st_dev is actually the same). Hence let's pin the inode in
                 * between via O_PATH, unless we already have an fd for it. */

                if (!isempty(filea)) {
                        pin_a = openat(fda, filea, O_PATH|O_CLOEXEC|(FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW) ? O_NOFOLLOW : 0));
                        if (pin_a < 0)
                                return -errno;

                        fda = pin_a;
                        filea = NULL;
                        flags |= AT_EMPTY_PATH;
                }

                if (!isempty(fileb)) {
                        pin_b = openat(fdb, fileb, O_PATH|O_CLOEXEC|(FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW) ? O_NOFOLLOW : 0));
                        if (pin_b < 0)
                                return -errno;

                        fdb = pin_b;
                        fileb = NULL;
                        flags |= AT_EMPTY_PATH;
                }

                int ntha_flags = at_flags_normalize_follow(flags) & (AT_EMPTY_PATH|AT_SYMLINK_FOLLOW);
                _cleanup_free_ struct file_handle *ha = NULL, *hb = NULL;
                int mntida = -1, mntidb = -1;

                r = name_to_handle_at_try_fid(
                                fda,
                                filea,
                                &ha,
                                &mntida,
                                ntha_flags);
                if (r < 0) {
                        if (is_name_to_handle_at_fatal_error(r))
                                return r;

                        goto fallback;
                }

                r = name_to_handle_at_try_fid(
                                fdb,
                                fileb,
                                &hb,
                                &mntidb,
                                ntha_flags);
                if (r < 0) {
                        if (is_name_to_handle_at_fatal_error(r))
                                return r;

                        goto fallback;
                }

                /* Now compare the two file handles */
                if (!file_handle_equal(ha, hb))
                        return false;

                /* If the file handles are the same and they come from the same mount ID? Great, then we are
                 * good, they are definitely the same */
                if (mntida == mntidb)
                        return true;

                /* File handles are the same, they are not on the same mount id. This might either be because
                 * they are on two entirely different file systems, that just happen to have the same FIDs
                 * (because they originally where created off the same disk images), or it could be because
                 * they are located on two distinct bind mounts of the same fs. To check that, let's look at
                 * .st_rdev of the inode. We simply reuse the fallback codepath for that, since it checks
                 * exactly that (it checks slightly more, but we don't care.) */
        }

fallback:
        if (fstatat(fda, strempty(filea), &sta, flags) < 0)
                return log_debug_errno(errno, "Cannot stat %s: %m", strna(filea));

        if (fstatat(fdb, strempty(fileb), &stb, flags) < 0)
                return log_debug_errno(errno, "Cannot stat %s: %m", strna(fileb));

        return stat_inode_same(&sta, &stb);
}

bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) {
        assert(s);
        assert_cc(sizeof(statfs_f_type_t) >= sizeof(s->f_type));

        return F_TYPE_EQUAL(s->f_type, magic_value);
}

int is_fs_type_at(int dir_fd, const char *path, statfs_f_type_t magic_value) {
        struct statfs s;
        int r;

        r = xstatfsat(dir_fd, path, &s);
        if (r < 0)
                return r;

        return is_fs_type(&s, magic_value);
}

bool is_temporary_fs(const struct statfs *s) {
        return fs_in_group(s, FILESYSTEM_SET_TEMPORARY);
}

bool is_network_fs(const struct statfs *s) {
        return fs_in_group(s, FILESYSTEM_SET_NETWORK);
}

int fd_is_temporary_fs(int fd) {
        struct statfs s;

        if (fstatfs(fd, &s) < 0)
                return -errno;

        return is_temporary_fs(&s);
}

int fd_is_network_fs(int fd) {
        struct statfs s;

        if (fstatfs(fd, &s) < 0)
                return -errno;

        return is_network_fs(&s);
}

int path_is_temporary_fs(const char *path) {
        struct statfs s;

        if (statfs(path, &s) < 0)
                return -errno;

        return is_temporary_fs(&s);
}

int path_is_network_fs(const char *path) {
        struct statfs s;

        if (statfs(path, &s) < 0)
                return -errno;

        return is_network_fs(&s);
}

int proc_mounted(void) {
        int r;

        /* A quick check of procfs is properly mounted */

        r = path_is_fs_type("/proc/", PROC_SUPER_MAGIC);
        if (r == -ENOENT) /* not mounted at all */
                return false;

        return r;
}

bool stat_inode_same(const struct stat *a, const struct stat *b) {

        /* Returns if the specified stat structure references the same (though possibly modified) inode. Does
         * a thorough check, comparing inode nr, backing device and if the inode is still of the same type. */

        return stat_is_set(a) && stat_is_set(b) &&
                ((a->st_mode ^ b->st_mode) & S_IFMT) == 0 &&  /* same inode type */
                a->st_dev == b->st_dev &&
                a->st_ino == b->st_ino;
}

bool stat_inode_unmodified(const struct stat *a, const struct stat *b) {

        /* Returns if the specified stat structures reference the same, unmodified inode. This check tries to
         * be reasonably careful when detecting changes: we check both inode and mtime, to cater for file
         * systems where mtimes are fixed to 0 (think: ostree/nixos type installations). We also check file
         * size, backing device, inode type and if this refers to a device not the major/minor.
         *
         * Note that we don't care if file attributes such as ownership or access mode change, this here is
         * about contents of the file. The purpose here is to detect file contents changes, and nothing
         * else. */

        return stat_inode_same(a, b) &&
                a->st_mtim.tv_sec == b->st_mtim.tv_sec &&
                a->st_mtim.tv_nsec == b->st_mtim.tv_nsec &&
                (!S_ISREG(a->st_mode) || a->st_size == b->st_size) && /* if regular file, compare file size */
                (!(S_ISCHR(a->st_mode) || S_ISBLK(a->st_mode)) || a->st_rdev == b->st_rdev); /* if device node, also compare major/minor, because we can */
}

bool statx_inode_same(const struct statx *a, const struct statx *b) {

        /* Same as stat_inode_same() but for struct statx */

        return statx_is_set(a) && statx_is_set(b) &&
                FLAGS_SET(a->stx_mask, STATX_TYPE|STATX_INO) && FLAGS_SET(b->stx_mask, STATX_TYPE|STATX_INO) &&
                ((a->stx_mode ^ b->stx_mode) & S_IFMT) == 0 &&
                a->stx_dev_major == b->stx_dev_major &&
                a->stx_dev_minor == b->stx_dev_minor &&
                a->stx_ino == b->stx_ino;
}

bool statx_mount_same(const struct statx *a, const struct statx *b) {
        if (!statx_is_set(a) || !statx_is_set(b))
                return false;

        /* if we have the mount ID, that's all we need */
        if (FLAGS_SET(a->stx_mask, STATX_MNT_ID) && FLAGS_SET(b->stx_mask, STATX_MNT_ID))
                return a->stx_mnt_id == b->stx_mnt_id;

        /* Otherwise, major/minor of backing device must match */
        return a->stx_dev_major == b->stx_dev_major &&
                a->stx_dev_minor == b->stx_dev_minor;
}

int xstatfsat(int dir_fd, const char *path, struct statfs *ret) {
        _cleanup_close_ int fd = -EBADF;

        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
        assert(ret);

        fd = xopenat(dir_fd, path, O_PATH|O_CLOEXEC|O_NOCTTY);
        if (fd < 0)
                return fd;

        return RET_NERRNO(fstatfs(fd, ret));
}

void inode_hash_func(const struct stat *q, struct siphash *state) {
        siphash24_compress_typesafe(q->st_dev, state);
        siphash24_compress_typesafe(q->st_ino, state);
}

int inode_compare_func(const struct stat *a, const struct stat *b) {
        int r;

        r = CMP(a->st_dev, b->st_dev);
        if (r != 0)
                return r;

        return CMP(a->st_ino, b->st_ino);
}

DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(inode_hash_ops, struct stat, inode_hash_func, inode_compare_func, free);

const char* inode_type_to_string(mode_t m) {

        /* Returns a short string for the inode type. We use the same name as the underlying macros for each
         * inode type. */

        switch (m & S_IFMT) {
        case S_IFREG:
                return "reg";
        case S_IFDIR:
                return "dir";
        case S_IFLNK:
                return "lnk";
        case S_IFCHR:
                return "chr";
        case S_IFBLK:
                return "blk";
        case S_IFIFO:
                return "fifo";
        case S_IFSOCK:
                return "sock";
        }

        /* Note anonymous inodes in the kernel will have a zero type. Hence fstat() of an eventfd() will
         * return an .st_mode where we'll return NULL here! */
        return NULL;
}

mode_t inode_type_from_string(const char *s) {
        if (!s)
                return MODE_INVALID;

        if (streq(s, "reg"))
                return S_IFREG;
        if (streq(s, "dir"))
                return S_IFDIR;
        if (streq(s, "lnk"))
                return S_IFLNK;
        if (streq(s, "chr"))
                return S_IFCHR;
        if (streq(s, "blk"))
                return S_IFBLK;
        if (streq(s, "fifo"))
                return S_IFIFO;
        if (streq(s, "sock"))
                return S_IFSOCK;

        return MODE_INVALID;
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <errno.h>
4	#include <fcntl.h>
5	#include <sched.h>
6	#include <sys/statvfs.h>
7	#include <sys/types.h>
8	#include <unistd.h>
9
10	#include "alloc-util.h"
11	#include "chase.h"
12	#include "dirent-util.h"
13	#include "errno-util.h"
14	#include "fd-util.h"
15	#include "fileio.h"
16	#include "filesystems.h"
17	#include "fs-util.h"
18	#include "hash-funcs.h"
19	#include "macro.h"
20	#include "missing_fs.h"
21	#include "missing_magic.h"
22	#include "mountpoint-util.h"
23	#include "nulstr-util.h"
24	#include "parse-util.h"
25	#include "stat-util.h"
26	#include "string-util.h"
27
28	static int verify_stat_at(	2,179,461✔
29	int fd,
30	const char *path,
31	bool follow,
32	int (verify_func)(const struct stat st),
33	bool verify) {
34
35	struct stat st;	2,179,461✔
36	int r;	2,179,461✔
37
38	assert(fd >= 0 \|\| fd == AT_FDCWD);	2,179,461✔
39	assert(!isempty(path) \|\| !follow);	2,179,461✔
40	assert(verify_func);	2,179,461✔
41
42	if (fstatat(fd, strempty(path), &st,	5,172,091✔
43	(isempty(path) ? AT_EMPTY_PATH : 0) \| (follow ? 0 : AT_SYMLINK_NOFOLLOW)) < 0)	2,179,461✔
44	return -errno;	8,760✔
45
46	r = verify_func(&st);	2,170,701✔
47	return verify ? r : r >= 0;	2,170,701✔
48	}
49
50	int stat_verify_regular(const struct stat *st) {	2,650,880✔
51	assert(st);	2,650,880✔
52
53	/* Checks whether the specified stat() structure refers to a regular file. If not returns an
54	* appropriate error code. */
55
56	if (S_ISDIR(st->st_mode))	2,650,880✔
57	return -EISDIR;
58
59	if (S_ISLNK(st->st_mode))	2,648,692✔
60	return -ELOOP;
61
62	if (!S_ISREG(st->st_mode))	2,648,678✔
63	return -EBADFD;	17✔
64
65	return 0;
66	}
67
68	int verify_regular_at(int fd, const char *path, bool follow) {	813,420✔
69	return verify_stat_at(fd, path, follow, stat_verify_regular, true);	813,420✔
70	}
71
72	int fd_verify_regular(int fd) {	813,153✔
73	assert(fd >= 0);	813,153✔
74	return verify_regular_at(fd, NULL, false);	813,153✔
75	}
76
77	int stat_verify_directory(const struct stat *st) {	1,397,417✔
78	assert(st);	1,397,417✔
79
80	if (S_ISLNK(st->st_mode))	1,397,417✔
81	return -ELOOP;
82
83	if (!S_ISDIR(st->st_mode))	1,397,408✔
84	return -ENOTDIR;	8✔
85
86	return 0;
87	}
88
89	int fd_verify_directory(int fd) {	13✔
90	assert(fd >= 0);	13✔
91	return verify_stat_at(fd, NULL, false, stat_verify_directory, true);	13✔
92	}
93
94	int is_dir_at(int fd, const char *path, bool follow) {	1,345,587✔
95	return verify_stat_at(fd, path, follow, stat_verify_directory, false);	1,345,587✔
96	}
97
98	int is_dir(const char *path, bool follow) {	483,828✔
99	assert(!isempty(path));	483,828✔
100	return is_dir_at(AT_FDCWD, path, follow);	483,828✔
101	}
102
103	int stat_verify_symlink(const struct stat *st) {	20,297✔
104	assert(st);	20,297✔
105
106	if (S_ISDIR(st->st_mode))	20,297✔
107	return -EISDIR;
108
109	if (!S_ISLNK(st->st_mode))	20,230✔
110	return -ENOLINK;	700✔
111
112	return 0;
113	}
114
115	int is_symlink(const char *path) {	20,297✔
116	assert(!isempty(path));	20,297✔
117	return verify_stat_at(AT_FDCWD, path, false, stat_verify_symlink, false);	20,297✔
118	}
119
120	int stat_verify_linked(const struct stat *st) {	1,809,093✔
121	assert(st);	1,809,093✔
122
123	if (st->st_nlink <= 0)	1,809,093✔
124	return -EIDRM; /* recognizable error. */	2✔
125
126	return 0;
127	}
128
129	int fd_verify_linked(int fd) {	3✔
130	assert(fd >= 0);	3✔
131	return verify_stat_at(fd, NULL, false, stat_verify_linked, true);	3✔
132	}
133
134	int stat_verify_device_node(const struct stat *st) {	7,978✔
135	assert(st);	7,978✔
136
137	if (S_ISLNK(st->st_mode))	7,978✔
138	return -ELOOP;
139
140	if (S_ISDIR(st->st_mode))	7,978✔
141	return -EISDIR;
142
143	if (!S_ISBLK(st->st_mode) && !S_ISCHR(st->st_mode))	7,845✔
144	return -ENOTTY;	5✔
145
146	return 0;
147	}
148
149	int is_device_node(const char *path) {	141✔
150	assert(!isempty(path));	141✔
151	return verify_stat_at(AT_FDCWD, path, false, stat_verify_device_node, false);	141✔
152	}
153
154	int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup) {	38,754✔
155	_cleanup_close_ int fd = -EBADF;	38,754✔
156	struct dirent *buf;	38,754✔
157	size_t m;	38,754✔
158
159	fd = xopenat(dir_fd, path, O_DIRECTORY\|O_CLOEXEC);	38,754✔
160	if (fd < 0)	38,754✔
161	return fd;
162
163	/* Allocate space for at least 3 full dirents, since every dir has at least two entries ("." +
164	* ".."), and only once we have seen if there's a third we know whether the dir is empty or not. If
165	* 'ignore_hidden_or_backup' is true we'll allocate a bit more, since we might skip over a bunch of
166	* entries that we end up ignoring. */
167	m = (ignore_hidden_or_backup ? 16 : 3) * DIRENT_SIZE_MAX;	3,223✔
168	buf = alloca(m);	3,223✔
169
170	for (;;) {	5,418✔
171	struct dirent *de;	5,418✔
172	ssize_t n;	5,418✔
173
174	n = posix_getdents(fd, buf, m, /* flags = */ 0);	5,418✔
175	if (n < 0)	5,418✔
UNCOV 176	return -errno;	×
177	if (n == 0)	5,418✔
178	break;
179
180	assert((size_t) n <= m);	3,223✔
181	msan_unpoison(buf, n);	3,223✔
182
183	FOREACH_DIRENT_IN_BUFFER(de, buf, n)	8,819✔
184	if (!(ignore_hidden_or_backup ? hidden_or_backup_file(de->d_name) : dot_or_dot_dot(de->d_name)))	6,624✔
185	return 0;
186	}
187
188	return 1;
189	}
190
191	bool null_or_empty(struct stat *st) {	355,675✔
192	assert(st);	355,675✔
193
194	if (S_ISREG(st->st_mode) && st->st_size <= 0)	355,675✔
195	return true;
196
197	/* We don't want to hardcode the major/minor of /dev/null, hence we do a simpler "is this a character
198	* device node?" check. */
199
200	if (S_ISCHR(st->st_mode))	355,663✔
201	return true;	849✔
202
203	return false;
204	}
205
206	int null_or_empty_path_with_root(const char fn, const char root) {	253,628✔
207	struct stat st;	253,628✔
208	int r;	253,628✔
209
210	assert(fn);	253,628✔
211
212	/* A symlink to /dev/null or an empty file?
213	* When looking under root_dir, we can't expect /dev/ to be mounted,
214	* so let's see if the path is a (possibly dangling) symlink to /dev/null. */
215
216	if (path_equal(path_startswith(fn, root ?: "/"), "dev/null"))	507,256✔
217	return true;	253,628✔
218
219	r = chase_and_stat(fn, root, CHASE_PREFIX_ROOT, NULL, &st);	253,466✔
220	if (r < 0)	253,466✔
221	return r;
222
223	return null_or_empty(&st);	253,352✔
224	}
225
226	int fd_is_read_only_fs(int fd) {	2,031✔
227	struct statvfs st;	2,031✔
228
229	assert(fd >= 0);	2,031✔
230
231	if (fstatvfs(fd, &st) < 0)	2,031✔
UNCOV 232	return -errno;	×
233
234	if (st.f_flag & ST_RDONLY)	2,031✔
235	return true;
236
237	/* On NFS, fstatvfs() might not reflect whether we can actually write to the remote share. Let's try
238	* again with access(W_OK) which is more reliable, at least sometimes. */
239	if (access_fd(fd, W_OK) == -EROFS)	1,671✔
UNCOV 240	return true;	×
241
242	return false;
243	}
244
245	int path_is_read_only_fs(const char *path) {	1,763✔
246	_cleanup_close_ int fd = -EBADF;	1,763✔
247
248	assert(path);	1,763✔
249
250	fd = open(path, O_CLOEXEC \| O_PATH);	1,763✔
251	if (fd < 0)	1,763✔
252	return -errno;	146✔
253
254	return fd_is_read_only_fs(fd);	1,617✔
255	}
256
257	int inode_same_at(int fda, const char filea, int fdb, const char fileb, int flags) {	14,260✔
258	struct stat sta, stb;	14,260✔
259	int r;	14,260✔
260
261	assert(fda >= 0 \|\| fda == AT_FDCWD);	14,260✔
262	assert(fdb >= 0 \|\| fdb == AT_FDCWD);	14,260✔
263	assert((flags & ~(AT_EMPTY_PATH\|AT_SYMLINK_NOFOLLOW\|AT_NO_AUTOMOUNT)) == 0);	14,260✔
264
265	/* Refuse an unset filea or fileb early unless AT_EMPTY_PATH is set */
266	if ((isempty(filea) \|\| isempty(fileb)) && !FLAGS_SET(flags, AT_EMPTY_PATH))	28,333✔
267	return -EINVAL;	14,260✔
268
269	/* Shortcut: comparing the same fd with itself means we can return true */
270	if (fda >= 0 && fda == fdb && isempty(filea) && isempty(fileb) && FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW))	14,262✔
271	return true;
272
273	_cleanup_close_ int pin_a = -EBADF, pin_b = -EBADF;	28,519✔
274	if (!FLAGS_SET(flags, AT_NO_AUTOMOUNT)) {	14,259✔
275	/* Let's try to use the name_to_handle_at() AT_HANDLE_FID API to identify identical
276	* inodes. We have to issue multiple calls on the same file for that (first, to acquire the
277	* FID, and then to check if .st_dev is actually the same). Hence let's pin the inode in
278	* between via O_PATH, unless we already have an fd for it. */
279
280	if (!isempty(filea)) {	14,259✔
281	pin_a = openat(fda, filea, O_PATH\|O_CLOEXEC\|(FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW) ? O_NOFOLLOW : 0));	14,073✔
282	if (pin_a < 0)	14,073✔
283	return -errno;	14,108✔
284
285	fda = pin_a;	13,535✔
286	filea = NULL;	13,535✔
287	flags \|= AT_EMPTY_PATH;	13,535✔
288	}
289
290	if (!isempty(fileb)) {	13,721✔
291	pin_b = openat(fdb, fileb, O_PATH\|O_CLOEXEC\|(FLAGS_SET(flags, AT_SYMLINK_NOFOLLOW) ? O_NOFOLLOW : 0));	13,533✔
292	if (pin_b < 0)	13,533✔
293	return -errno;	4✔
294
295	fdb = pin_b;	13,529✔
296	fileb = NULL;	13,529✔
297	flags \|= AT_EMPTY_PATH;	13,529✔
298	}
299
300	int ntha_flags = at_flags_normalize_follow(flags) & (AT_EMPTY_PATH\|AT_SYMLINK_FOLLOW);	13,717✔
301	_cleanup_free_ struct file_handle ha = NULL, hb = NULL;	13,717✔
302	int mntida = -1, mntidb = -1;	13,717✔
303
304	r = name_to_handle_at_try_fid(	13,717✔
305	fda,
306	filea,
307	&ha,
308	&mntida,
309	ntha_flags);
310	if (r < 0) {	13,717✔
UNCOV 311	if (is_name_to_handle_at_fatal_error(r))	×
312	return r;
313
UNCOV 314	goto fallback;	×
315	}
316
317	r = name_to_handle_at_try_fid(	13,717✔
318	fdb,
319	fileb,
320	&hb,
321	&mntidb,
322	ntha_flags);
323	if (r < 0) {	13,717✔
UNCOV 324	if (is_name_to_handle_at_fatal_error(r))	×
325	return r;
326
UNCOV 327	goto fallback;	×
328	}
329
330	/* Now compare the two file handles */
331	if (!file_handle_equal(ha, hb))	13,717✔
332	return false;
333
334	/* If the file handles are the same and they come from the same mount ID? Great, then we are
335	* good, they are definitely the same */
336	if (mntida == mntidb)	13,452✔
337	return true;
338
339	/* File handles are the same, they are not on the same mount id. This might either be because
340	* they are on two entirely different file systems, that just happen to have the same FIDs
341	* (because they originally where created off the same disk images), or it could be because
342	* they are located on two distinct bind mounts of the same fs. To check that, let's look at
343	* .st_rdev of the inode. We simply reuse the fallback codepath for that, since it checks
344	* exactly that (it checks slightly more, but we don't care.) */
345	}
346
UNCOV 347	fallback:	×
348	if (fstatat(fda, strempty(filea), &sta, flags) < 0)	302✔
UNCOV 349	return log_debug_errno(errno, "Cannot stat %s: %m", strna(filea));	×
350
351	if (fstatat(fdb, strempty(fileb), &stb, flags) < 0)	302✔
UNCOV 352	return log_debug_errno(errno, "Cannot stat %s: %m", strna(fileb));	×
353
354	return stat_inode_same(&sta, &stb);	151✔
355	}
356
357	bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) {	9,450,737✔
358	assert(s);	9,450,737✔
359	assert_cc(sizeof(statfs_f_type_t) >= sizeof(s->f_type));	9,450,737✔
360
361	return F_TYPE_EQUAL(s->f_type, magic_value);	9,450,737✔
362	}
363
364	int is_fs_type_at(int dir_fd, const char *path, statfs_f_type_t magic_value) {	9,143,776✔
365	struct statfs s;	9,143,776✔
366	int r;	9,143,776✔
367
368	r = xstatfsat(dir_fd, path, &s);	9,143,776✔
369	if (r < 0)	9,143,776✔
370	return r;	9,143,776✔
371
372	return is_fs_type(&s, magic_value);	9,143,775✔
373	}
374
375	bool is_temporary_fs(const struct statfs *s) {	43,541✔
376	return fs_in_group(s, FILESYSTEM_SET_TEMPORARY);	43,541✔
377	}
378
379	bool is_network_fs(const struct statfs *s) {	15,667✔
380	return fs_in_group(s, FILESYSTEM_SET_NETWORK);	15,667✔
381	}
382
383	int fd_is_temporary_fs(int fd) {	199✔
384	struct statfs s;	199✔
385
386	if (fstatfs(fd, &s) < 0)	199✔
UNCOV 387	return -errno;	×
388
389	return is_temporary_fs(&s);	199✔
390	}
391
392	int fd_is_network_fs(int fd) {	15,564✔
393	struct statfs s;	15,564✔
394
395	if (fstatfs(fd, &s) < 0)	15,564✔
UNCOV 396	return -errno;	×
397
398	return is_network_fs(&s);	15,564✔
399	}
400
401	int path_is_temporary_fs(const char *path) {	11✔
402	struct statfs s;	11✔
403
404	if (statfs(path, &s) < 0)	11✔
405	return -errno;	2✔
406
407	return is_temporary_fs(&s);	9✔
408	}
409
UNCOV 410	int path_is_network_fs(const char *path) {	×
411	struct statfs s;	×
412
UNCOV 413	if (statfs(path, &s) < 0)	×
414	return -errno;	×
415
UNCOV 416	return is_network_fs(&s);	×
417	}
418
419	int proc_mounted(void) {	17,958✔
420	int r;	17,958✔
421
422	/* A quick check of procfs is properly mounted */
423
424	r = path_is_fs_type("/proc/", PROC_SUPER_MAGIC);	17,958✔
425	if (r == -ENOENT) /* not mounted at all */	17,958✔
UNCOV 426	return false;	×
427
428	return r;
429	}
430
431	bool stat_inode_same(const struct stat a, const struct stat b) {	1,301,889✔
432
433	/* Returns if the specified stat structure references the same (though possibly modified) inode. Does
434	* a thorough check, comparing inode nr, backing device and if the inode is still of the same type. */
435
436	return stat_is_set(a) && stat_is_set(b) &&	2,601,767✔
437	((a->st_mode ^ b->st_mode) & S_IFMT) == 0 && /* same inode type */	1,258,319✔
438	a->st_dev == b->st_dev &&	2,514,593✔
439	a->st_ino == b->st_ino;	1,212,704✔
440	}
441
442	bool stat_inode_unmodified(const struct stat a, const struct stat b) {	120,941✔
443
444	/* Returns if the specified stat structures reference the same, unmodified inode. This check tries to
445	* be reasonably careful when detecting changes: we check both inode and mtime, to cater for file
446	* systems where mtimes are fixed to 0 (think: ostree/nixos type installations). We also check file
447	* size, backing device, inode type and if this refers to a device not the major/minor.
448	*
449	* Note that we don't care if file attributes such as ownership or access mode change, this here is
450	* about contents of the file. The purpose here is to detect file contents changes, and nothing
451	* else. */
452
453	return stat_inode_same(a, b) &&	120,941✔
454	a->st_mtim.tv_sec == b->st_mtim.tv_sec &&	70,824✔
455	a->st_mtim.tv_nsec == b->st_mtim.tv_nsec &&	70,689✔
456	(!S_ISREG(a->st_mode) \|\| a->st_size == b->st_size) && /* if regular file, compare file size */	191,615✔
457	(!(S_ISCHR(a->st_mode) \|\| S_ISBLK(a->st_mode)) \|\| a->st_rdev == b->st_rdev); /* if device node, also compare major/minor, because we can */	70,674✔
458	}
459
460	bool statx_inode_same(const struct statx a, const struct statx b) {	3,617,757✔
461
462	/* Same as stat_inode_same() but for struct statx */
463
464	return statx_is_set(a) && statx_is_set(b) &&	7,235,514✔
465	FLAGS_SET(a->stx_mask, STATX_TYPE\|STATX_INO) && FLAGS_SET(b->stx_mask, STATX_TYPE\|STATX_INO) &&	3,617,757✔
466	((a->stx_mode ^ b->stx_mode) & S_IFMT) == 0 &&	3,617,757✔
467	a->stx_dev_major == b->stx_dev_major &&	3,617,757✔
468	a->stx_dev_minor == b->stx_dev_minor &&	6,937,995✔
469	a->stx_ino == b->stx_ino;	3,320,238✔
470	}
471
472	bool statx_mount_same(const struct statx a, const struct statx b) {	3,290,901✔
473	if (!statx_is_set(a) \|\| !statx_is_set(b))	6,581,802✔
474	return false;
475
476	/* if we have the mount ID, that's all we need */
477	if (FLAGS_SET(a->stx_mask, STATX_MNT_ID) && FLAGS_SET(b->stx_mask, STATX_MNT_ID))	3,290,901✔
478	return a->stx_mnt_id == b->stx_mnt_id;	3,290,901✔
479
480	/* Otherwise, major/minor of backing device must match */
UNCOV 481	return a->stx_dev_major == b->stx_dev_major &&	×
482	a->stx_dev_minor == b->stx_dev_minor;
483	}
484
485	int xstatfsat(int dir_fd, const char path, struct statfs ret) {	9,144,160✔
486	_cleanup_close_ int fd = -EBADF;	9,144,160✔
487
488	assert(dir_fd >= 0 \|\| dir_fd == AT_FDCWD);	9,144,160✔
489	assert(ret);	9,144,160✔
490
491	fd = xopenat(dir_fd, path, O_PATH\|O_CLOEXEC\|O_NOCTTY);	9,144,160✔
492	if (fd < 0)	9,144,160✔
493	return fd;
494
495	return RET_NERRNO(fstatfs(fd, ret));	9,144,160✔
496	}
497
498	void inode_hash_func(const struct stat q, struct siphash state) {	37,326✔
499	siphash24_compress_typesafe(q->st_dev, state);	37,326✔
500	siphash24_compress_typesafe(q->st_ino, state);	37,326✔
501	}	37,326✔
502
503	int inode_compare_func(const struct stat a, const struct stat b) {	31,157✔
504	int r;	31,157✔
505
506	r = CMP(a->st_dev, b->st_dev);	31,157✔
507	if (r != 0)	26,304✔
508	return r;	4,928✔
509
510	return CMP(a->st_ino, b->st_ino);	26,229✔
511	}
512
513	DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(inode_hash_ops, struct stat, inode_hash_func, inode_compare_func, free);	761✔
514
515	const char* inode_type_to_string(mode_t m) {	10,016✔
516
517	/* Returns a short string for the inode type. We use the same name as the underlying macros for each
518	* inode type. */
519
520	switch (m & S_IFMT) {	10,016✔
521	case S_IFREG:
522	return "reg";
523	case S_IFDIR:	3,955✔
524	return "dir";	3,955✔
525	case S_IFLNK:	1✔
526	return "lnk";	1✔
527	case S_IFCHR:	932✔
528	return "chr";	932✔
529	case S_IFBLK:	487✔
530	return "blk";	487✔
531	case S_IFIFO:	487✔
532	return "fifo";	487✔
533	case S_IFSOCK:	639✔
534	return "sock";	639✔
535	}
536
537	/* Note anonymous inodes in the kernel will have a zero type. Hence fstat() of an eventfd() will
538	* return an .st_mode where we'll return NULL here! */
539	return NULL;	3✔
540	}
541
542	mode_t inode_type_from_string(const char *s) {	13✔
543	if (!s)	13✔
544	return MODE_INVALID;
545
546	if (streq(s, "reg"))	13✔
547	return S_IFREG;
548	if (streq(s, "dir"))	10✔
549	return S_IFDIR;
550	if (streq(s, "lnk"))	7✔
551	return S_IFLNK;
552	if (streq(s, "chr"))	6✔
553	return S_IFCHR;
554	if (streq(s, "blk"))	5✔
555	return S_IFBLK;
556	if (streq(s, "fifo"))	4✔
557	return S_IFIFO;
558	if (streq(s, "sock"))	2✔
559	return S_IFSOCK;	2✔
560
561	return MODE_INVALID;
562	}

systemd / systemd / 13665439908

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