Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 503 insertions, 0 deletions

diff --git a/src/basic/recurse-dir.c b/src/basic/recurse-dir.c
new file mode 100644
index 0000000..5e98b7a
--- /dev/null
+++ b/src/basic/recurse-dir.c
@@ -0,0 +1,503 @@
+/* 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);
+}