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recurse-dir: optionally, only enumerate dentries of a specific type

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At various places we filter directory enumerations by inode type. Let's
add explicit support for that, so that the "struct dirent" array we
return already suppresses them.

This shortens code and makes things more robust.
This commit is contained in:
Lennart Poettering
2026-06-22 14:40:16 +02:00
parent fe83c5be7f
commit 90d285ade7
9 changed files with 129 additions and 55 deletions
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src/basic/recurse-dir.c
+41 -6
View File
@@ -27,6 +27,35 @@ static bool ignore_dirent(const struct dirent *de, RecurseDirFlags flags) {
/* Depending on flag either ignore everything starting with ".", or just "." itself and ".." */
if ((flags & _RECURSE_DIR_MUST_BE_MASK) != 0) {
RecurseDirFlags f;
switch (de->d_type) {
case DT_DIR:
f = RECURSE_DIR_MUST_BE_DIRECTORY;
break;
case DT_REG:
f = RECURSE_DIR_MUST_BE_REGULAR;
break;
case DT_LNK:
f = RECURSE_DIR_MUST_BE_SYMLINK;
break;
case DT_SOCK:
f = RECURSE_DIR_MUST_BE_SOCKET;
break;
default:
return true;
}
if (!FLAGS_SET(flags, f))
return true;
}
return FLAGS_SET(flags, RECURSE_DIR_IGNORE_DOT) ?
de->d_name[0] == '.' :
dot_or_dot_dot(de->d_name);
@@ -39,6 +68,9 @@ int readdir_all(int dir_fd, RecurseDirFlags flags, DirectoryEntries **ret) {
assert(dir_fd >= 0);
if ((flags & _RECURSE_DIR_MUST_BE_MASK) != 0) /* We need the type to validate it */
flags |= RECURSE_DIR_ENSURE_TYPE;
/* Returns an array with pointers to "struct dirent" directory entries, optionally sorted.
*
* Start with space for up to 8 directory entries. We expect at least 2 ("." + ".."), hence hopefully
@@ -87,9 +119,6 @@ int readdir_all(int dir_fd, RecurseDirFlags flags, DirectoryEntries **ret) {
de->n_entries = 0;
struct dirent *entry;
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)
@@ -99,6 +128,9 @@ int readdir_all(int dir_fd, RecurseDirFlags flags, DirectoryEntries **ret) {
return r;
}
if (ignore_dirent(entry, flags))
continue;
de->n_entries++;
}
@@ -117,14 +149,14 @@ int readdir_all(int dir_fd, RecurseDirFlags flags, DirectoryEntries **ret) {
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;
if (ignore_dirent(entry, flags))
continue;
de->entries[j++] = entry;
}
assert(j == de->n_entries);
@@ -166,6 +198,9 @@ int recurse_dir(
assert(dir_fd >= 0);
assert(func);
/* We cannot descend into dirs if we are supposed to ignore them */
assert((flags & _RECURSE_DIR_MUST_BE_MASK) == 0 || FLAGS_SET(flags, RECURSE_DIR_MUST_BE_DIRECTORY));
/* 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. */
src/basic/recurse-dir.h
+11 -6
View File
@@ -7,14 +7,19 @@
typedef enum RecurseDirFlags {
/* Interpreted by readdir_all() */
RECURSE_DIR_SORT = 1 << 0, /* sort file directory entries before processing them */
RECURSE_DIR_IGNORE_DOT = 1 << 1, /* ignore all dot files ("." and ".." are always ignored) */
RECURSE_DIR_ENSURE_TYPE = 1 << 2, /* guarantees that 'd_type' field of 'de' is not DT_UNKNOWN */
RECURSE_DIR_SORT = 1 << 0, /* sort file directory entries before processing them */
RECURSE_DIR_IGNORE_DOT = 1 << 1, /* ignore all dot files ("." and ".." are always ignored) */
RECURSE_DIR_ENSURE_TYPE = 1 << 2, /* guarantees that 'd_type' field of 'de' is not DT_UNKNOWN */
RECURSE_DIR_MUST_BE_DIRECTORY = 1 << 3, /* ignore all entries that aren't directories */
RECURSE_DIR_MUST_BE_REGULAR = 1 << 4, /* ignore all entries that aren't regular files */
RECURSE_DIR_MUST_BE_SYMLINK = 1 << 5, /* ignore all entries that aren't symlinks */
RECURSE_DIR_MUST_BE_SOCKET = 1 << 6, /* ignore all entries that aren't socket */
_RECURSE_DIR_MUST_BE_MASK = RECURSE_DIR_MUST_BE_DIRECTORY|RECURSE_DIR_MUST_BE_REGULAR|RECURSE_DIR_MUST_BE_SYMLINK|RECURSE_DIR_MUST_BE_SOCKET,
/* Interpreted by recurse_dir() */
RECURSE_DIR_SAME_MOUNT = 1 << 3, /* skips over subdirectories that are submounts */
RECURSE_DIR_INODE_FD = 1 << 4, /* passes an opened inode fd (O_DIRECTORY fd in case of dirs, O_PATH otherwise) */
RECURSE_DIR_TOPLEVEL = 1 << 5, /* call RECURSE_DIR_ENTER/RECURSE_DIR_LEAVE once for top-level dir, too, with dir_fd=-1 and NULL dirent */
RECURSE_DIR_SAME_MOUNT = 1 << 7, /* skips over subdirectories that are submounts */
RECURSE_DIR_INODE_FD = 1 << 8, /* passes an opened inode fd (O_DIRECTORY fd in case of dirs, O_PATH otherwise) */
RECURSE_DIR_TOPLEVEL = 1 << 9, /* call RECURSE_DIR_ENTER/RECURSE_DIR_LEAVE once for top-level dir, too, with dir_fd=-1 and NULL dirent */
} RecurseDirFlags;
typedef struct DirectoryEntries {
src/debug-generator/debug-generator.c
+1 -4
View File
@@ -279,7 +279,7 @@ static int process_unit_credentials(const char *credentials_dir) {
assert(credentials_dir);
r = readdir_all_at(AT_FDCWD, credentials_dir, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &des);
r = readdir_all_at(AT_FDCWD, credentials_dir, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_REGULAR, &des);
if (r < 0)
return log_error_errno(r, "Failed to enumerate credentials from credentials directory '%s': %m", credentials_dir);
@@ -287,9 +287,6 @@ static int process_unit_credentials(const char *credentials_dir) {
struct dirent *de = *i;
const char *unit, *dropin;
if (de->d_type != DT_REG)
continue;
unit = startswith(de->d_name, "systemd.extra-unit.");
dropin = startswith(de->d_name, "systemd.unit-dropin.");
src/kernel-install/kernel-install.c
+2 -23
View File
@@ -11,7 +11,6 @@
#include "build.h"
#include "chase.h"
#include "conf-files.h"
#include "dirent-util.h"
#include "dissect-image.h"
#include "env-file.h"
#include "env-util.h"
@@ -1247,21 +1246,11 @@ static int verb_add_all(int argc, char *argv[], uintptr_t _data, void *userdata)
return log_error_errno(fd, "Failed to open %s/usr/lib/modules/: %m", strempty(arg_root));
_cleanup_free_ DirectoryEntries *de = NULL;
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT, &de);
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_DIRECTORY, &de);
if (r < 0)
return log_error_errno(r, "Failed to numerate /usr/lib/modules/ contents: %m");
FOREACH_ARRAY(d, de->entries, de->n_entries) {
r = dirent_ensure_type(fd, *d);
if (r < 0) {
if (r != -ENOENT) /* don't log if just gone by now */
log_debug_errno(r, "Failed to check if '%s/usr/lib/modules/%s' is a directory, ignoring: %m", strempty(arg_root), (*d)->d_name);
continue;
}
if ((*d)->d_type != DT_DIR)
continue;
_cleanup_free_ char *fn = path_join((*d)->d_name, "vmlinuz");
if (!fn)
return log_oom();
@@ -1483,7 +1472,7 @@ static int verb_list(int argc, char *argv[], uintptr_t _data, void *userdata) {
return log_error_errno(fd, "Failed to open %s/usr/lib/modules/: %m", strempty(arg_root));
_cleanup_free_ DirectoryEntries *de = NULL;
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT, &de);
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_DIRECTORY, &de);
if (r < 0)
return log_error_errno(r, "Failed to numerate /usr/lib/modules/ contents: %m");
@@ -1501,16 +1490,6 @@ static int verb_list(int argc, char *argv[], uintptr_t _data, void *userdata) {
if (!j)
return log_oom();
r = dirent_ensure_type(fd, *d);
if (r < 0) {
if (r != -ENOENT) /* don't log if just gone by now */
log_debug_errno(r, "Failed to check if '%s/%s' is a directory, ignoring: %m", strempty(arg_root), j);
continue;
}
if ((*d)->d_type != DT_DIR)
continue;
_cleanup_free_ char *fn = path_join((*d)->d_name, "vmlinuz");
if (!fn)
return log_oom();
src/libsystemd/sd-varlink/varlink-util.c
+1 -4
View File
@@ -272,7 +272,7 @@ ssize_t varlink_execute_directory(
return log_debug_errno(errno, "Failed to open '%s': %m", path);
_cleanup_free_ DirectoryEntries *dentries = NULL;
r = readdir_all(fd, RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &dentries);
r = readdir_all(fd, RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_SOCKET|RECURSE_DIR_MUST_BE_SYMLINK, &dentries);
if (r < 0)
return log_debug_errno(r, "Failed to enumerate '%s': %m", path);
@@ -282,9 +282,6 @@ ssize_t varlink_execute_directory(
FOREACH_ARRAY(dp, dentries->entries, dentries->n_entries) {
struct dirent *de = *dp;
if (!IN_SET(de->d_type, DT_SOCK, DT_LNK))
continue;
t++;
_cleanup_free_ char *j = path_join(path, de->d_name);
src/nsresourced/userns-registry.c
+1 -4
View File
@@ -1219,7 +1219,7 @@ int userns_registry_per_uid(int dir_fd, uid_t owner) {
_cleanup_free_ DirectoryEntries *de = NULL;
r = readdir_all_at(dir_fd, uid_fn, RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &de);
r = readdir_all_at(dir_fd, uid_fn, RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_REGULAR, &de);
if (r == -ENOENT)
return 0;
if (r < 0)
@@ -1228,9 +1228,6 @@ int userns_registry_per_uid(int dir_fd, uid_t owner) {
FOREACH_ARRAY(i, de->entries, de->n_entries) {
struct dirent *e = *i;
if (e->d_type != DT_REG)
continue;
if (!startswith(e->d_name, "i") || !endswith(e->d_name, ".userns"))
continue;
src/shared/creds-util.c
+1 -4
View File
@@ -1805,16 +1805,13 @@ int pick_up_credentials(const PickUpCredential *table, size_t n_table_entry) {
return log_error_errno(credential_dir_fd, "Failed to open credentials directory: %m");
_cleanup_free_ DirectoryEntries *des = NULL;
r = readdir_all(credential_dir_fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &des);
r = readdir_all(credential_dir_fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_REGULAR, &des);
if (r < 0)
return log_error_errno(r, "Failed to enumerate credentials: %m");
FOREACH_ARRAY(i, des->entries, des->n_entries) {
struct dirent *de = *i;
if (de->d_type != DT_REG)
continue;
FOREACH_ARRAY(t, table, n_table_entry) {
r = pick_up_credential_one(credential_dir_fd, de->d_name, t);
if (r != 0) {
src/storage/storagectl.c
+1 -4
View File
@@ -348,16 +348,13 @@ static int verb_providers(int argc, char *argv[], uintptr_t data, void *userdata
return log_error_errno(errno, "Failed to open '%s': %m", socket_path);
} else {
_cleanup_free_ DirectoryEntries *dentries = NULL;
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &dentries);
r = readdir_all(fd, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_MUST_BE_SOCKET, &dentries);
if (r < 0)
return log_error_errno(r, "Failed to enumerate '%s': %m", socket_path);
FOREACH_ARRAY(dp, dentries->entries, dentries->n_entries) {
struct dirent *de = *dp;
if (de->d_type != DT_SOCK)
continue;
if (!storage_provider_name_is_valid(de->d_name))
continue;
src/test/test-recurse-dir.c
+70
View File
@@ -2,14 +2,17 @@
#include <ftw.h>
#include <linux/magic.h>
#include <sys/stat.h>
#include "fd-util.h"
#include "log.h"
#include "recurse-dir.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "strv.h"
#include "tests.h"
#include "time-util.h"
#include "tmpfile-util.h"
static char **list_nftw = NULL;
@@ -119,6 +122,71 @@ static int recurse_dir_callback(
return RECURSE_DIR_CONTINUE;
}
static void assert_entries(DirectoryEntries *de, char **expected) {
ASSERT_NOT_NULL(de);
/* Verifies that the directory entries enumerated in 'de' are exactly the ones listed in
* 'expected' (order is irrelevant). */
ASSERT_EQ(de->n_entries, strv_length(expected));
FOREACH_ARRAY(i, de->entries, de->n_entries)
ASSERT_TRUE(strv_contains(expected, (*i)->d_name));
STRV_FOREACH(e, expected) {
bool found = false;
FOREACH_ARRAY(i, de->entries, de->n_entries)
if (streq((*i)->d_name, *e)) {
found = true;
break;
}
ASSERT_TRUE(found);
}
}
static void check_readdir_all(int tfd, RecurseDirFlags flags, char **expected) {
_cleanup_free_ DirectoryEntries *de = NULL;
_cleanup_close_ int fd = -EBADF;
/* readdir_all() consumes the directory fd offset, hence reopen a fresh fd for each enumeration. */
ASSERT_OK(fd = fd_reopen(tfd, O_DIRECTORY|O_CLOEXEC));
ASSERT_OK(readdir_all(fd, flags, &de));
assert_entries(de, expected);
}
static void test_must_be_flags(void) {
_cleanup_(rm_rf_physical_and_freep) char *t = NULL;
_cleanup_close_ int tfd = -EBADF, reg_fd = -EBADF;
log_info("/* %s */", __func__);
/* Populate a temporary directory with one entry of each interesting type and verify that the
* RECURSE_DIR_MUST_BE_* flags select exactly the right subset. */
ASSERT_OK(tfd = mkdtemp_open(NULL, O_DIRECTORY|O_CLOEXEC, &t));
ASSERT_OK_ERRNO(mkdirat(tfd, "dir", 0777));
ASSERT_OK_ERRNO(reg_fd = openat(tfd, "reg", O_CREAT|O_EXCL|O_WRONLY|O_CLOEXEC, 0666));
reg_fd = safe_close(reg_fd);
ASSERT_OK_ERRNO(symlinkat("reg", tfd, "lnk"));
ASSERT_OK_ERRNO(mknodat(tfd, "sock", S_IFSOCK|0666, 0));
/* Without any MUST_BE flag we get all four entries. */
check_readdir_all(tfd, 0, STRV_MAKE("dir", "reg", "lnk", "sock"));
/* A single MUST_BE flag selects exactly the entries of the matching type. */
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_DIRECTORY, STRV_MAKE("dir"));
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_REGULAR, STRV_MAKE("reg"));
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_SYMLINK, STRV_MAKE("lnk"));
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_SOCKET, STRV_MAKE("sock"));
/* The flags may be combined, in which case we get the union of the matching entries. */
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_REGULAR|RECURSE_DIR_MUST_BE_SYMLINK, STRV_MAKE("reg", "lnk"));
check_readdir_all(tfd, RECURSE_DIR_MUST_BE_DIRECTORY|RECURSE_DIR_MUST_BE_SOCKET, STRV_MAKE("dir", "sock"));
}
int main(int argc, char *argv[]) {
_cleanup_strv_free_ char **list_recurse_dir = NULL;
const char *p;
@@ -128,6 +196,8 @@ int main(int argc, char *argv[]) {
log_show_color(true);
test_setup_logging(LOG_INFO);
test_must_be_flags();
if (argc > 1)
p = argv[1];
else