[thirdparty/systemd.git] / src / basic / recurse-dir.c

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

#include "alloc-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "missing_syscall.h"
#include "mountpoint-util.h"
#include "recurse-dir.h"
#include "sort-util.h"

#define DEFAULT_RECURSION_MAX 100

static int sort_func(struct dirent * const *a, struct dirent * const *b) {
        return strcmp((*a)->d_name, (*b)->d_name);
}

static bool ignore_dirent(const struct dirent *de, RecurseDirFlags flags) {
        assert(de);

        /* Depending on flag either ignore everything starting with ".", or just "." itself and ".." */

        return FLAGS_SET(flags, RECURSE_DIR_IGNORE_DOT) ?
                de->d_name[0] == '.' :
                dot_or_dot_dot(de->d_name);
}

int readdir_all(int dir_fd,
                RecurseDirFlags flags,
                DirectoryEntries **ret) {

        _cleanup_free_ DirectoryEntries *de = NULL;
        struct dirent *entry;
        DirectoryEntries *nde;
        size_t add, sz, j;
        int r;

        assert(dir_fd >= 0);

        /* Returns an array with pointers to "struct dirent" directory entries, optionally sorted. Free the
         * array with readdir_all_freep().
         *
         * Start with space for up to 8 directory entries. We expect at least 2 ("." + ".."), hence hopefully
         * 8 will cover most cases comprehensively. (Note that most likely a lot more entries will actually
         * fit in the buffer, given we calculate maximum file name length here.) */
        de = malloc(offsetof(DirectoryEntries, buffer) + DIRENT_SIZE_MAX * 8);
        if (!de)
                return -ENOMEM;

        de->buffer_size = 0;
        for (;;) {
                size_t bs;
                ssize_t n;

                bs = MIN(MALLOC_SIZEOF_SAFE(de) - offsetof(DirectoryEntries, buffer), (size_t) SSIZE_MAX);
                assert(bs > de->buffer_size);

                n = getdents64(dir_fd, (uint8_t*) de->buffer + de->buffer_size, bs - de->buffer_size);
                if (n < 0)
                        return -errno;
                if (n == 0)
                        break;

                msan_unpoison((uint8_t*) de->buffer + de->buffer_size, n);

                de->buffer_size += n;

                if (de->buffer_size < bs - DIRENT_SIZE_MAX) /* Still room for one more entry, then try to
                                                             * fill it up without growing the structure. */
                        continue;

                if (bs >= SSIZE_MAX - offsetof(DirectoryEntries, buffer))
                        return -EFBIG;
                bs = bs >= (SSIZE_MAX - offsetof(DirectoryEntries, buffer))/2 ? SSIZE_MAX - offsetof(DirectoryEntries, buffer) : bs * 2;

                nde = realloc(de, bs);
                if (!nde)
                        return -ENOMEM;

                de = nde;
        }

        de->n_entries = 0;
        FOREACH_DIRENT_IN_BUFFER(entry, de->buffer, de->buffer_size) {
                if (ignore_dirent(entry, flags))
                        continue;

                if (FLAGS_SET(flags, RECURSE_DIR_ENSURE_TYPE)) {
                        r = dirent_ensure_type(dir_fd, entry);
                        if (r == -ENOENT)
                                /* dentry gone by now? no problem, let's just suppress it */
                                continue;
                        if (r < 0)
                                return r;
                }

                de->n_entries++;
        }

        sz = ALIGN(offsetof(DirectoryEntries, buffer) + de->buffer_size);
        add = sizeof(struct dirent*) * de->n_entries;
        if (add > SIZE_MAX - add)
                return -ENOMEM;

        nde = realloc(de, sz + add);
        if (!nde)
                return -ENOMEM;

        de = nde;
        de->entries = (struct dirent**) ((uint8_t*) de + ALIGN(offsetof(DirectoryEntries, buffer) + de->buffer_size));

        j = 0;
        FOREACH_DIRENT_IN_BUFFER(entry, de->buffer, de->buffer_size) {
                if (ignore_dirent(entry, flags))
                        continue;

                /* If d_type == DT_UNKNOWN that means we failed to ensure the type in the earlier loop and
                 * didn't include the dentry in de->n_entries and as such should skip it here as well. */
                if (FLAGS_SET(flags, RECURSE_DIR_ENSURE_TYPE) && entry->d_type == DT_UNKNOWN)
                        continue;

                de->entries[j++] = entry;
        }
        assert(j == de->n_entries);

        if (FLAGS_SET(flags, RECURSE_DIR_SORT))
                typesafe_qsort(de->entries, de->n_entries, sort_func);

        if (ret)
                *ret = TAKE_PTR(de);

        return 0;
}

int recurse_dir(
                int dir_fd,
                const char *path,
                unsigned statx_mask,
                unsigned n_depth_max,
                RecurseDirFlags flags,
                recurse_dir_func_t func,
                void *userdata) {

        _cleanup_free_ DirectoryEntries *de = NULL;
        STRUCT_STATX_DEFINE(root_sx);
        int r;

        assert(dir_fd >= 0);
        assert(func);

        /* This is a lot like ftw()/nftw(), but a lot more modern, i.e. built around openat()/statx()/O_PATH,
         * and under the assumption that fds are not as 'expensive' as they used to be. */

        if (n_depth_max == 0)
                return -EOVERFLOW;
        if (n_depth_max == UINT_MAX) /* special marker for "default" */
                n_depth_max = DEFAULT_RECURSION_MAX;

        if (FLAGS_SET(flags, RECURSE_DIR_TOPLEVEL)) {
                if (statx_mask != 0) {
                        r = statx_fallback(dir_fd, "", AT_EMPTY_PATH, statx_mask, &root_sx);
                        if (r < 0)
                                return r;
                }

                r = func(RECURSE_DIR_ENTER,
                         path,
                         -1, /* we have no parent fd */
                         dir_fd,
                         NULL, /* we have no dirent */
                         statx_mask != 0 ? &root_sx : NULL,
                         userdata);
                if (IN_SET(r, RECURSE_DIR_LEAVE_DIRECTORY, RECURSE_DIR_SKIP_ENTRY))
                        return 0;
                if (r != RECURSE_DIR_CONTINUE)
                        return r;
        }

        /* Mask out RECURSE_DIR_ENSURE_TYPE so we can do it ourselves and avoid an extra statx() call. */
        r = readdir_all(dir_fd, flags & ~RECURSE_DIR_ENSURE_TYPE, &de);
        if (r < 0)
                return r;

        for (size_t i = 0; i < de->n_entries; i++) {
                _cleanup_close_ int inode_fd = -EBADF, subdir_fd = -EBADF;
                _cleanup_free_ char *joined = NULL;
                STRUCT_STATX_DEFINE(sx);
                bool sx_valid = false;
                const char *p;

                /* For each directory entry we'll do one of the following:
                 *
                 * 1) If the entry refers to a directory, we'll open it as O_DIRECTORY 'subdir_fd' and then statx() the opened directory via that new fd (if requested)
                 * 2) Otherwise, if RECURSE_DIR_INODE_FD is set we'll open it as O_PATH 'inode_fd' and then statx() the opened inode via that new fd (if requested)
                 * 3) Otherwise, we'll statx() the directory entry via the directory fd we are currently looking at (if requested)
                 */

                if (path) {
                        joined = path_join(path, de->entries[i]->d_name);
                        if (!joined)
                                return -ENOMEM;

                        p = joined;
                } else
                        p = de->entries[i]->d_name;

                if (IN_SET(de->entries[i]->d_type, DT_UNKNOWN, DT_DIR)) {
                        subdir_fd = openat(dir_fd, de->entries[i]->d_name, O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC);
                        if (subdir_fd < 0) {
                                if (errno == ENOENT) /* Vanished by now, go for next file immediately */
                                        continue;

                                /* If it is a subdir but we failed to open it, then fail */
                                if (!IN_SET(errno, ENOTDIR, ELOOP)) {
                                        log_debug_errno(errno, "Failed to open directory '%s': %m", p);

                                        assert(errno <= RECURSE_DIR_SKIP_OPEN_DIR_ERROR_MAX - RECURSE_DIR_SKIP_OPEN_DIR_ERROR_BASE);

                                        r = func(RECURSE_DIR_SKIP_OPEN_DIR_ERROR_BASE + errno,
                                                 p,
                                                 dir_fd,
                                                 -1,
                                                 de->entries[i],
                                                 NULL,
                                                 userdata);
                                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                                break;
                                        if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                                return r;

                                        continue;
                                }

                                /* If it's not a subdir, then let's handle it like a regular inode below */

                        } else {
                                /* If we managed to get a DIR* off the inode, it's definitely a directory. */
                                de->entries[i]->d_type = DT_DIR;

                                if (statx_mask != 0 || (flags & RECURSE_DIR_SAME_MOUNT)) {
                                        r = statx_fallback(subdir_fd, "", AT_EMPTY_PATH, statx_mask, &sx);
                                        if (r < 0)
                                                return r;

                                        sx_valid = true;
                                }
                        }
                }

                if (subdir_fd < 0) {
                        /* It's not a subdirectory. */

                        if (flags & RECURSE_DIR_INODE_FD) {

                                inode_fd = openat(dir_fd, de->entries[i]->d_name, O_PATH|O_NOFOLLOW|O_CLOEXEC);
                                if (inode_fd < 0) {
                                        if (errno == ENOENT) /* Vanished by now, go for next file immediately */
                                                continue;

                                        log_debug_errno(errno, "Failed to open directory entry '%s': %m", p);

                                        assert(errno <= RECURSE_DIR_SKIP_OPEN_INODE_ERROR_MAX - RECURSE_DIR_SKIP_OPEN_INODE_ERROR_BASE);

                                        r = func(RECURSE_DIR_SKIP_OPEN_INODE_ERROR_BASE + errno,
                                                 p,
                                                 dir_fd,
                                                 -1,
                                                 de->entries[i],
                                                 NULL,
                                                 userdata);
                                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                                break;
                                        if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                                return r;

                                        continue;
                                }

                                /* If we open the inode, then verify it's actually a non-directory, like we
                                 * assume. Let's guarantee that we never pass statx data of a directory where
                                 * caller expects a non-directory */

                                r = statx_fallback(inode_fd, "", AT_EMPTY_PATH, statx_mask | STATX_TYPE, &sx);
                                if (r < 0)
                                        return r;

                                assert(sx.stx_mask & STATX_TYPE);
                                sx_valid = true;

                                if (S_ISDIR(sx.stx_mode)) {
                                        /* What? It's a directory now? Then someone must have quickly
                                         * replaced it. Let's handle that gracefully: convert it to a
                                         * directory fd — which should be riskless now that we pinned the
                                         * inode. */

                                        subdir_fd = fd_reopen(inode_fd, O_DIRECTORY|O_CLOEXEC);
                                        if (subdir_fd < 0)
                                                return subdir_fd;

                                        inode_fd = safe_close(inode_fd);
                                }

                        } else if (statx_mask != 0 || (de->entries[i]->d_type == DT_UNKNOWN && (flags & RECURSE_DIR_ENSURE_TYPE))) {

                                r = statx_fallback(dir_fd, de->entries[i]->d_name, AT_SYMLINK_NOFOLLOW, statx_mask | STATX_TYPE, &sx);
                                if (r == -ENOENT) /* Vanished by now? Go for next file immediately */
                                        continue;
                                if (r < 0) {
                                        log_debug_errno(r, "Failed to stat directory entry '%s': %m", p);

                                        assert(errno <= RECURSE_DIR_SKIP_STAT_INODE_ERROR_MAX - RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE);

                                        r = func(RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE + -r,
                                                 p,
                                                 dir_fd,
                                                 -1,
                                                 de->entries[i],
                                                 NULL,
                                                 userdata);
                                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                                break;
                                        if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                                return r;

                                        continue;
                                }

                                assert(sx.stx_mask & STATX_TYPE);
                                sx_valid = true;

                                if (S_ISDIR(sx.stx_mode)) {
                                        /* So it suddenly is a directory, but we couldn't open it as such
                                         * earlier?  That is weird, and probably means somebody is racing
                                         * against us. We could of course retry and open it as a directory
                                         * again, but the chance to win here is limited. Hence, let's
                                         * propagate this as EISDIR error instead. That way we make this
                                         * something that can be reasonably handled, even though we give the
                                         * guarantee that RECURSE_DIR_ENTRY is strictly issued for
                                         * non-directory dirents. */

                                        log_debug_errno(r, "Non-directory entry '%s' suddenly became a directory: %m", p);

                                        r = func(RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE + EISDIR,
                                                 p,
                                                 dir_fd,
                                                 -1,
                                                 de->entries[i],
                                                 NULL,
                                                 userdata);
                                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                                break;
                                        if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                                return r;

                                        continue;
                                }
                        }
                }

                if (sx_valid) {
                        /* Copy over the data we acquired through statx() if we acquired any */
                        if (sx.stx_mask & STATX_TYPE) {
                                assert((subdir_fd < 0) == !S_ISDIR(sx.stx_mode));
                                de->entries[i]->d_type = IFTODT(sx.stx_mode);
                        }

                        if (sx.stx_mask & STATX_INO)
                                de->entries[i]->d_ino = sx.stx_ino;
                }

                if (subdir_fd >= 0) {
                        if (FLAGS_SET(flags, RECURSE_DIR_SAME_MOUNT)) {
                                bool is_mount;

                                if (sx_valid && FLAGS_SET(sx.stx_attributes_mask, STATX_ATTR_MOUNT_ROOT))
                                        is_mount = FLAGS_SET(sx.stx_attributes, STATX_ATTR_MOUNT_ROOT);
                                else {
                                        r = fd_is_mount_point(dir_fd, de->entries[i]->d_name, 0);
                                        if (r < 0)
                                                log_debug_errno(r, "Failed to determine whether %s is a submount, assuming not: %m", p);

                                        is_mount = r > 0;
                                }

                                if (is_mount) {
                                        r = func(RECURSE_DIR_SKIP_MOUNT,
                                                 p,
                                                 dir_fd,
                                                 subdir_fd,
                                                 de->entries[i],
                                                 statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
                                                 userdata);
                                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                                break;
                                        if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                                return r;

                                        continue;
                                }
                        }

                        if (n_depth_max <= 1) {
                                /* When we reached max depth, generate a special event */

                                r = func(RECURSE_DIR_SKIP_DEPTH,
                                         p,
                                         dir_fd,
                                         subdir_fd,
                                         de->entries[i],
                                         statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
                                         userdata);
                                if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                        break;
                                if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
                                        return r;

                                continue;
                        }

                        r = func(RECURSE_DIR_ENTER,
                                 p,
                                 dir_fd,
                                 subdir_fd,
                                 de->entries[i],
                                 statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
                                 userdata);
                        if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                                break;
                        if (r == RECURSE_DIR_SKIP_ENTRY)
                                continue;
                        if (r != RECURSE_DIR_CONTINUE)
                                return r;

                        r = recurse_dir(subdir_fd,
                                        p,
                                        statx_mask,
                                        n_depth_max - 1,
                                        flags &~ RECURSE_DIR_TOPLEVEL, /* we already called the callback for this entry */
                                        func,
                                        userdata);
                        if (r != 0)
                                return r;

                        r = func(RECURSE_DIR_LEAVE,
                                 p,
                                 dir_fd,
                                 subdir_fd,
                                 de->entries[i],
                                 statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
                                 userdata);
                } else
                        /* Non-directory inode */
                        r = func(RECURSE_DIR_ENTRY,
                                 p,
                                 dir_fd,
                                 inode_fd,
                                 de->entries[i],
                                 statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
                                 userdata);


                if (r == RECURSE_DIR_LEAVE_DIRECTORY)
                        break;
                if (!IN_SET(r, RECURSE_DIR_SKIP_ENTRY, RECURSE_DIR_CONTINUE))
                        return r;
        }

        if (FLAGS_SET(flags, RECURSE_DIR_TOPLEVEL)) {

                r = func(RECURSE_DIR_LEAVE,
                         path,
                         -1,
                         dir_fd,
                         NULL,
                         statx_mask != 0 ? &root_sx : NULL,
                         userdata);
                if (!IN_SET(r, RECURSE_DIR_LEAVE_DIRECTORY, RECURSE_DIR_SKIP_ENTRY, RECURSE_DIR_CONTINUE))
                        return r;
        }

        return 0;
}

int recurse_dir_at(
                int atfd,
                const char *path,
                unsigned statx_mask,
                unsigned n_depth_max,
                RecurseDirFlags flags,
                recurse_dir_func_t func,
                void *userdata) {

        _cleanup_close_ int fd = -EBADF;

        assert(atfd >= 0 || atfd == AT_FDCWD);
        assert(func);

        fd = openat(atfd, path ?: ".", O_DIRECTORY|O_CLOEXEC);
        if (fd < 0)
                return -errno;

        return recurse_dir(fd, path, statx_mask, n_depth_max, flags, func, userdata);
}
Commit	Line	Data
b5a07e52 LP	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
	2
	3	#include "alloc-util.h"
	4	#include "dirent-util.h"
	5	#include "fd-util.h"
	6	#include "fileio.h"
6393b847	7	#include "missing_syscall.h"
b5a07e52 LP	8	#include "mountpoint-util.h"
	9	#include "recurse-dir.h"
	10	#include "sort-util.h"
	11
	12	#define DEFAULT_RECURSION_MAX 100
	13
	14	static int sort_func(struct dirent * const a, struct dirent const *b) {
	15	return strcmp((a)->d_name, (b)->d_name);
	16	}
	17
6393b847 LP	18	static bool ignore_dirent(const struct dirent *de, RecurseDirFlags flags) {
6393b847 LP	19	assert(de);
b5a07e52	20
6393b847	21	/* Depending on flag either ignore everything starting with ".", or just "." itself and ".." */
b5a07e52	22
6393b847 LP	23	return FLAGS_SET(flags, RECURSE_DIR_IGNORE_DOT) ?
	24	de->d_name[0] == '.' :
	25	dot_or_dot_dot(de->d_name);
b5a07e52 LP	26	}
b5a07e52 LP	27
6393b847	28	int readdir_all(int dir_fd,
b5a07e52	29	RecurseDirFlags flags,
6393b847	30	DirectoryEntries **ret) {
b5a07e52	31
6393b847	32	_cleanup_free_ DirectoryEntries *de = NULL;
a4e70ef7	33	struct dirent *entry;
6393b847 LP	34	DirectoryEntries *nde;
6393b847 LP	35	size_t add, sz, j;
a0a4c578	36	int r;
b5a07e52	37
6393b847	38	assert(dir_fd >= 0);
b5a07e52 LP	39
b5a07e52 LP	40	/* Returns an array with pointers to "struct dirent" directory entries, optionally sorted. Free the
ca664db2 LP	41	* array with readdir_all_freep().
	42	*
	43	* Start with space for up to 8 directory entries. We expect at least 2 ("." + ".."), hence hopefully
6393b847 LP	44	* 8 will cover most cases comprehensively. (Note that most likely a lot more entries will actually
	45	* fit in the buffer, given we calculate maximum file name length here.) */
	46	de = malloc(offsetof(DirectoryEntries, buffer) + DIRENT_SIZE_MAX * 8);
	47	if (!de)
	48	return -ENOMEM;
	49
	50	de->buffer_size = 0;
b5a07e52	51	for (;;) {
6393b847 LP	52	size_t bs;
6393b847 LP	53	ssize_t n;
b5a07e52	54
6393b847 LP	55	bs = MIN(MALLOC_SIZEOF_SAFE(de) - offsetof(DirectoryEntries, buffer), (size_t) SSIZE_MAX);
6393b847 LP	56	assert(bs > de->buffer_size);
b5a07e52	57
a4e70ef7	58	n = getdents64(dir_fd, (uint8_t*) de->buffer + de->buffer_size, bs - de->buffer_size);
6393b847	59	if (n < 0)
b5a07e52	60	return -errno;
6393b847 LP	61	if (n == 0)
6393b847 LP	62	break;
b5a07e52	63
0dbce03c LP	64	msan_unpoison((uint8_t*) de->buffer + de->buffer_size, n);
0dbce03c LP	65
6393b847 LP	66	de->buffer_size += n;
	67
	68	if (de->buffer_size < bs - DIRENT_SIZE_MAX) /* Still room for one more entry, then try to
	69	* fill it up without growing the structure. */
b5a07e52 LP	70	continue;
b5a07e52 LP	71
6393b847 LP	72	if (bs >= SSIZE_MAX - offsetof(DirectoryEntries, buffer))
	73	return -EFBIG;
	74	bs = bs >= (SSIZE_MAX - offsetof(DirectoryEntries, buffer))/2 ? SSIZE_MAX - offsetof(DirectoryEntries, buffer) : bs * 2;
b5a07e52	75
6393b847 LP	76	nde = realloc(de, bs);
6393b847 LP	77	if (!nde)
b5a07e52 LP	78	return -ENOMEM;
b5a07e52 LP	79
6393b847 LP	80	de = nde;
	81	}
	82
	83	de->n_entries = 0;
a4e70ef7	84	FOREACH_DIRENT_IN_BUFFER(entry, de->buffer, de->buffer_size) {
6393b847 LP	85	if (ignore_dirent(entry, flags))
6393b847 LP	86	continue;
b5a07e52	87
a0a4c578 DDM	88	if (FLAGS_SET(flags, RECURSE_DIR_ENSURE_TYPE)) {
	89	r = dirent_ensure_type(dir_fd, entry);
	90	if (r == -ENOENT)
	91	/* dentry gone by now? no problem, let's just suppress it */
	92	continue;
	93	if (r < 0)
	94	return r;
	95	}
	96
6393b847 LP	97	de->n_entries++;
	98	}
	99
	100	sz = ALIGN(offsetof(DirectoryEntries, buffer) + de->buffer_size);
	101	add = sizeof(struct dirent) de->n_entries;
	102	if (add > SIZE_MAX - add)
	103	return -ENOMEM;
	104
	105	nde = realloc(de, sz + add);
	106	if (!nde)
	107	return -ENOMEM;
	108
	109	de = nde;
	110	de->entries = (struct dirent*) ((uint8_t) de + ALIGN(offsetof(DirectoryEntries, buffer) + de->buffer_size));
	111
	112	j = 0;
a4e70ef7	113	FOREACH_DIRENT_IN_BUFFER(entry, de->buffer, de->buffer_size) {
6393b847 LP	114	if (ignore_dirent(entry, flags))
	115	continue;
	116
a0a4c578 DDM	117	/* If d_type == DT_UNKNOWN that means we failed to ensure the type in the earlier loop and
	118	* didn't include the dentry in de->n_entries and as such should skip it here as well. */
	119	if (FLAGS_SET(flags, RECURSE_DIR_ENSURE_TYPE) && entry->d_type == DT_UNKNOWN)
	120	continue;
	121
6393b847	122	de->entries[j++] = entry;
b5a07e52	123	}
a0a4c578	124	assert(j == de->n_entries);
b5a07e52 LP	125
b5a07e52 LP	126	if (FLAGS_SET(flags, RECURSE_DIR_SORT))
6393b847	127	typesafe_qsort(de->entries, de->n_entries, sort_func);
b5a07e52 LP	128
b5a07e52 LP	129	if (ret)
6393b847	130	*ret = TAKE_PTR(de);
b5a07e52	131
6393b847	132	return 0;
b5a07e52 LP	133	}
	134
	135	int recurse_dir(
6393b847	136	int dir_fd,
b5a07e52 LP	137	const char *path,
	138	unsigned statx_mask,
	139	unsigned n_depth_max,
	140	RecurseDirFlags flags,
	141	recurse_dir_func_t func,
	142	void *userdata) {
	143
6393b847	144	_cleanup_free_ DirectoryEntries *de = NULL;
b21ec07b	145	STRUCT_STATX_DEFINE(root_sx);
6393b847	146	int r;
b5a07e52	147
6393b847	148	assert(dir_fd >= 0);
b5a07e52 LP	149	assert(func);
b5a07e52 LP	150
6393b847 LP	151	/* This is a lot like ftw()/nftw(), but a lot more modern, i.e. built around openat()/statx()/O_PATH,
6393b847 LP	152	* and under the assumption that fds are not as 'expensive' as they used to be. */
b5a07e52 LP	153
	154	if (n_depth_max == 0)
	155	return -EOVERFLOW;
	156	if (n_depth_max == UINT_MAX) /* special marker for "default" */
	157	n_depth_max = DEFAULT_RECURSION_MAX;
	158
b21ec07b LP	159	if (FLAGS_SET(flags, RECURSE_DIR_TOPLEVEL)) {
	160	if (statx_mask != 0) {
	161	r = statx_fallback(dir_fd, "", AT_EMPTY_PATH, statx_mask, &root_sx);
	162	if (r < 0)
	163	return r;
	164	}
	165
	166	r = func(RECURSE_DIR_ENTER,
	167	path,
	168	-1, /* we have no parent fd */
	169	dir_fd,
	170	NULL, /* we have no dirent */
	171	statx_mask != 0 ? &root_sx : NULL,
	172	userdata);
	173	if (IN_SET(r, RECURSE_DIR_LEAVE_DIRECTORY, RECURSE_DIR_SKIP_ENTRY))
	174	return 0;
	175	if (r != RECURSE_DIR_CONTINUE)
	176	return r;
	177	}
	178
a0a4c578 DDM	179	/* Mask out RECURSE_DIR_ENSURE_TYPE so we can do it ourselves and avoid an extra statx() call. */
a0a4c578 DDM	180	r = readdir_all(dir_fd, flags & ~RECURSE_DIR_ENSURE_TYPE, &de);
6393b847 LP	181	if (r < 0)
6393b847 LP	182	return r;
b5a07e52	183
6393b847	184	for (size_t i = 0; i < de->n_entries; i++) {
254d1313	185	_cleanup_close_ int inode_fd = -EBADF, subdir_fd = -EBADF;
b5a07e52	186	_cleanup_free_ char *joined = NULL;
b5a07e52 LP	187	STRUCT_STATX_DEFINE(sx);
	188	bool sx_valid = false;
	189	const char *p;
	190
	191	/* For each directory entry we'll do one of the following:
	192	*
6393b847 LP	193	* 1) If the entry refers to a directory, we'll open it as O_DIRECTORY 'subdir_fd' and then statx() the opened directory via that new fd (if requested)
	194	* 2) Otherwise, if RECURSE_DIR_INODE_FD is set we'll open it as O_PATH 'inode_fd' and then statx() the opened inode via that new fd (if requested)
	195	* 3) Otherwise, we'll statx() the directory entry via the directory fd we are currently looking at (if requested)
b5a07e52 LP	196	*/
	197
	198	if (path) {
6393b847	199	joined = path_join(path, de->entries[i]->d_name);
b5a07e52 LP	200	if (!joined)
	201	return -ENOMEM;
	202
	203	p = joined;
	204	} else
6393b847	205	p = de->entries[i]->d_name;
b5a07e52	206
6393b847 LP	207	if (IN_SET(de->entries[i]->d_type, DT_UNKNOWN, DT_DIR)) {
	208	subdir_fd = openat(dir_fd, de->entries[i]->d_name, O_DIRECTORY\|O_NOFOLLOW\|O_CLOEXEC);
	209	if (subdir_fd < 0) {
b5a07e52 LP	210	if (errno == ENOENT) /* Vanished by now, go for next file immediately */
	211	continue;
	212
	213	/* If it is a subdir but we failed to open it, then fail */
	214	if (!IN_SET(errno, ENOTDIR, ELOOP)) {
	215	log_debug_errno(errno, "Failed to open directory '%s': %m", p);
	216
	217	assert(errno <= RECURSE_DIR_SKIP_OPEN_DIR_ERROR_MAX - RECURSE_DIR_SKIP_OPEN_DIR_ERROR_BASE);
	218
	219	r = func(RECURSE_DIR_SKIP_OPEN_DIR_ERROR_BASE + errno,
	220	p,
6393b847	221	dir_fd,
b5a07e52	222	-1,
6393b847	223	de->entries[i],
b5a07e52 LP	224	NULL,
	225	userdata);
	226	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	227	break;
	228	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	229	return r;
	230
	231	continue;
	232	}
	233
	234	/* If it's not a subdir, then let's handle it like a regular inode below */
	235
	236	} else {
	237	/* If we managed to get a DIR* off the inode, it's definitely a directory. */
6393b847	238	de->entries[i]->d_type = DT_DIR;
b5a07e52 LP	239
b5a07e52 LP	240	if (statx_mask != 0 \|\| (flags & RECURSE_DIR_SAME_MOUNT)) {
6393b847	241	r = statx_fallback(subdir_fd, "", AT_EMPTY_PATH, statx_mask, &sx);
b5a07e52 LP	242	if (r < 0)
	243	return r;
	244
	245	sx_valid = true;
	246	}
	247	}
	248	}
	249
6393b847	250	if (subdir_fd < 0) {
b5a07e52 LP	251	/* It's not a subdirectory. */
	252
	253	if (flags & RECURSE_DIR_INODE_FD) {
	254
6393b847	255	inode_fd = openat(dir_fd, de->entries[i]->d_name, O_PATH\|O_NOFOLLOW\|O_CLOEXEC);
b5a07e52 LP	256	if (inode_fd < 0) {
	257	if (errno == ENOENT) /* Vanished by now, go for next file immediately */
	258	continue;
	259
	260	log_debug_errno(errno, "Failed to open directory entry '%s': %m", p);
	261
	262	assert(errno <= RECURSE_DIR_SKIP_OPEN_INODE_ERROR_MAX - RECURSE_DIR_SKIP_OPEN_INODE_ERROR_BASE);
	263
	264	r = func(RECURSE_DIR_SKIP_OPEN_INODE_ERROR_BASE + errno,
	265	p,
6393b847	266	dir_fd,
b5a07e52	267	-1,
6393b847	268	de->entries[i],
b5a07e52 LP	269	NULL,
	270	userdata);
	271	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	272	break;
	273	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	274	return r;
	275
	276	continue;
	277	}
	278
	279	/* If we open the inode, then verify it's actually a non-directory, like we
	280	* assume. Let's guarantee that we never pass statx data of a directory where
	281	* caller expects a non-directory */
	282
	283	r = statx_fallback(inode_fd, "", AT_EMPTY_PATH, statx_mask \| STATX_TYPE, &sx);
	284	if (r < 0)
	285	return r;
	286
	287	assert(sx.stx_mask & STATX_TYPE);
	288	sx_valid = true;
	289
	290	if (S_ISDIR(sx.stx_mode)) {
	291	/* What? It's a directory now? Then someone must have quickly
	292	* replaced it. Let's handle that gracefully: convert it to a
ba669952	293	* directory fd — which should be riskless now that we pinned the
b5a07e52 LP	294	* inode. */
b5a07e52 LP	295
739d9cae	296	subdir_fd = fd_reopen(inode_fd, O_DIRECTORY\|O_CLOEXEC);
6393b847	297	if (subdir_fd < 0)
739d9cae	298	return subdir_fd;
b5a07e52 LP	299
	300	inode_fd = safe_close(inode_fd);
	301	}
	302
6393b847	303	} else if (statx_mask != 0 \|\| (de->entries[i]->d_type == DT_UNKNOWN && (flags & RECURSE_DIR_ENSURE_TYPE))) {
b5a07e52	304
6393b847	305	r = statx_fallback(dir_fd, de->entries[i]->d_name, AT_SYMLINK_NOFOLLOW, statx_mask \| STATX_TYPE, &sx);
b5a07e52 LP	306	if (r == -ENOENT) /* Vanished by now? Go for next file immediately */
	307	continue;
	308	if (r < 0) {
	309	log_debug_errno(r, "Failed to stat directory entry '%s': %m", p);
	310
	311	assert(errno <= RECURSE_DIR_SKIP_STAT_INODE_ERROR_MAX - RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE);
	312
	313	r = func(RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE + -r,
	314	p,
6393b847	315	dir_fd,
b5a07e52	316	-1,
6393b847	317	de->entries[i],
b5a07e52 LP	318	NULL,
	319	userdata);
	320	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	321	break;
	322	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	323	return r;
	324
	325	continue;
	326	}
	327
	328	assert(sx.stx_mask & STATX_TYPE);
	329	sx_valid = true;
	330
	331	if (S_ISDIR(sx.stx_mode)) {
	332	/* So it suddenly is a directory, but we couldn't open it as such
	333	* earlier? That is weird, and probably means somebody is racing
	334	* against us. We could of course retry and open it as a directory
	335	* again, but the chance to win here is limited. Hence, let's
	336	* propagate this as EISDIR error instead. That way we make this
	337	* something that can be reasonably handled, even though we give the
	338	* guarantee that RECURSE_DIR_ENTRY is strictly issued for
	339	* non-directory dirents. */
	340
	341	log_debug_errno(r, "Non-directory entry '%s' suddenly became a directory: %m", p);
	342
	343	r = func(RECURSE_DIR_SKIP_STAT_INODE_ERROR_BASE + EISDIR,
	344	p,
6393b847	345	dir_fd,
b5a07e52	346	-1,
6393b847	347	de->entries[i],
b5a07e52 LP	348	NULL,
	349	userdata);
	350	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	351	break;
	352	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	353	return r;
	354
	355	continue;
	356	}
	357	}
	358	}
	359
	360	if (sx_valid) {
	361	/* Copy over the data we acquired through statx() if we acquired any */
	362	if (sx.stx_mask & STATX_TYPE) {
6393b847 LP	363	assert((subdir_fd < 0) == !S_ISDIR(sx.stx_mode));
6393b847 LP	364	de->entries[i]->d_type = IFTODT(sx.stx_mode);
b5a07e52 LP	365	}
	366
	367	if (sx.stx_mask & STATX_INO)
6393b847	368	de->entries[i]->d_ino = sx.stx_ino;
b5a07e52 LP	369	}
b5a07e52 LP	370
6393b847	371	if (subdir_fd >= 0) {
b5a07e52 LP	372	if (FLAGS_SET(flags, RECURSE_DIR_SAME_MOUNT)) {
	373	bool is_mount;
	374
	375	if (sx_valid && FLAGS_SET(sx.stx_attributes_mask, STATX_ATTR_MOUNT_ROOT))
	376	is_mount = FLAGS_SET(sx.stx_attributes, STATX_ATTR_MOUNT_ROOT);
	377	else {
6393b847	378	r = fd_is_mount_point(dir_fd, de->entries[i]->d_name, 0);
b5a07e52 LP	379	if (r < 0)
	380	log_debug_errno(r, "Failed to determine whether %s is a submount, assuming not: %m", p);
	381
	382	is_mount = r > 0;
	383	}
	384
	385	if (is_mount) {
	386	r = func(RECURSE_DIR_SKIP_MOUNT,
	387	p,
6393b847 LP	388	dir_fd,
	389	subdir_fd,
	390	de->entries[i],
b5a07e52 LP	391	statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
	392	userdata);
	393	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	394	break;
	395	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	396	return r;
	397
	398	continue;
	399	}
	400	}
	401
	402	if (n_depth_max <= 1) {
	403	/* When we reached max depth, generate a special event */
	404
	405	r = func(RECURSE_DIR_SKIP_DEPTH,
	406	p,
6393b847 LP	407	dir_fd,
	408	subdir_fd,
	409	de->entries[i],
b5a07e52 LP	410	statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
	411	userdata);
	412	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	413	break;
	414	if (!IN_SET(r, RECURSE_DIR_CONTINUE, RECURSE_DIR_SKIP_ENTRY))
	415	return r;
	416
	417	continue;
	418	}
	419
	420	r = func(RECURSE_DIR_ENTER,
	421	p,
6393b847 LP	422	dir_fd,
	423	subdir_fd,
	424	de->entries[i],
b5a07e52 LP	425	statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
	426	userdata);
	427	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	428	break;
	429	if (r == RECURSE_DIR_SKIP_ENTRY)
	430	continue;
	431	if (r != RECURSE_DIR_CONTINUE)
	432	return r;
	433
6393b847	434	r = recurse_dir(subdir_fd,
b5a07e52 LP	435	p,
	436	statx_mask,
	437	n_depth_max - 1,
b21ec07b	438	flags &~ RECURSE_DIR_TOPLEVEL, /* we already called the callback for this entry */
b5a07e52 LP	439	func,
	440	userdata);
	441	if (r != 0)
	442	return r;
	443
	444	r = func(RECURSE_DIR_LEAVE,
	445	p,
6393b847 LP	446	dir_fd,
	447	subdir_fd,
	448	de->entries[i],
b5a07e52 LP	449	statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
	450	userdata);
	451	} else
	452	/* Non-directory inode */
	453	r = func(RECURSE_DIR_ENTRY,
	454	p,
6393b847	455	dir_fd,
b5a07e52	456	inode_fd,
6393b847	457	de->entries[i],
b5a07e52 LP	458	statx_mask != 0 ? &sx : NULL, /* only pass sx if user asked for it */
	459	userdata);
	460
	461
	462	if (r == RECURSE_DIR_LEAVE_DIRECTORY)
	463	break;
	464	if (!IN_SET(r, RECURSE_DIR_SKIP_ENTRY, RECURSE_DIR_CONTINUE))
	465	return r;
	466	}
	467
b21ec07b LP	468	if (FLAGS_SET(flags, RECURSE_DIR_TOPLEVEL)) {
	469
	470	r = func(RECURSE_DIR_LEAVE,
	471	path,
	472	-1,
	473	dir_fd,
	474	NULL,
	475	statx_mask != 0 ? &root_sx : NULL,
	476	userdata);
	477	if (!IN_SET(r, RECURSE_DIR_LEAVE_DIRECTORY, RECURSE_DIR_SKIP_ENTRY, RECURSE_DIR_CONTINUE))
	478	return r;
	479	}
	480
b5a07e52 LP	481	return 0;
	482	}
	483
	484	int recurse_dir_at(
	485	int atfd,
	486	const char *path,
	487	unsigned statx_mask,
	488	unsigned n_depth_max,
	489	RecurseDirFlags flags,
	490	recurse_dir_func_t func,
	491	void *userdata) {
	492
254d1313	493	_cleanup_close_ int fd = -EBADF;
6393b847 LP	494
	495	assert(atfd >= 0 \|\| atfd == AT_FDCWD);
	496	assert(func);
	497
aa3cc58a	498	fd = openat(atfd, path ?: ".", O_DIRECTORY\|O_CLOEXEC);
6393b847	499	if (fd < 0)
b5a07e52 LP	500	return -errno;
b5a07e52 LP	501
6393b847	502	return recurse_dir(fd, path, statx_mask, n_depth_max, flags, func, userdata);
b5a07e52	503	}