stat-util: introduce a common (stat|fd)_verify_regular_or_block() helper

We already had one in repart.c, let's generalize it, and use it
everywhere.

src/basic/stat-util.c

@@ -220,6 +220,28 @@ int is_device_node(const char *path) {
         return verify_stat_at(AT_FDCWD, path, false, stat_verify_device_node, false);
 }
 
+int stat_verify_regular_or_block(const struct stat *st) {
+        assert(st);
+
+        if (S_ISDIR(st->st_mode))
+                return -EISDIR;
+
+        if (S_ISLNK(st->st_mode))
+                return -ELOOP;
+
+        if (!S_ISREG(st->st_mode) && !S_ISBLK(st->st_mode))
+                return -EBADFD;
+
+        return 0;
+}
+
+int fd_verify_regular_or_block(int fd) {
+        if (IN_SET(fd, AT_FDCWD, XAT_FDROOT))
+                return -EISDIR;
+
+        return verify_stat_at(fd, /* path= */ NULL, /* follow= */ false, stat_verify_regular_or_block, /* verify= */ true);
+}
+
 int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup) {
         _cleanup_close_ int fd = -EBADF;
         struct dirent *buf;

src/basic/stat-util.h

@@ -31,6 +31,9 @@ int fd_verify_linked(int fd);
 int stat_verify_device_node(const struct stat *st);
 int is_device_node(const char *path);
 
+int stat_verify_regular_or_block(const struct stat *st);
+int fd_verify_regular_or_block(int fd);
+
 int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup);
 static inline int dir_is_empty(const char *path, bool ignore_hidden_or_backup) {
         return dir_is_empty_at(AT_FDCWD, path, ignore_hidden_or_backup);

src/home/homework-luks.c

@@ -1250,10 +1250,9 @@ static int open_image_file(
 
         if (fstat(image_fd, &st) < 0)
                 return log_error_errno(errno, "Failed to fstat() image file: %m");
-        if (!S_ISREG(st.st_mode) && !S_ISBLK(st.st_mode))
-                return log_error_errno(
-                                S_ISDIR(st.st_mode) ? SYNTHETIC_ERRNO(EISDIR) : SYNTHETIC_ERRNO(EBADFD),
-                                "Image file %s is not a regular file or block device.", ip);
+        r = stat_verify_regular_or_block(&st);
+        if (r < 0)
+                return log_error_errno(r, "Image file '%s' is not a regular file or block device.", ip);
 
         /* Locking block devices doesn't really make sense, as this might interfere with
          * udev's workings, and these locks aren't network propagated anyway, hence not what

src/import/import-raw.c

@@ -22,6 +22,7 @@
 #include "pretty-print.h"
 #include "qcow2-util.h"
 #include "ratelimit.h"
+#include "stat-util.h"
 #include "string-util.h"
 #include "terminal-util.h"
 #include "time-util.h"
@@ -309,9 +310,9 @@ static int raw_import_open_disk(RawImport *i) {
         if (fstat(i->output_fd, &i->output_stat) < 0)
                 return log_error_errno(errno, "Failed to stat() output file: %m");
 
-        if (!S_ISREG(i->output_stat.st_mode) && !S_ISBLK(i->output_stat.st_mode))
-                return log_error_errno(SYNTHETIC_ERRNO(EBADFD),
-                                       "Target file is not a regular file or block device");
+        r = stat_verify_regular_or_block(&i->output_stat);
+        if (r < 0)
+                return log_error_errno(r, "Target file is not a regular file or block device.");
 
         if (i->offset != UINT64_MAX) {
                 if (lseek(i->output_fd, i->offset, SEEK_SET) < 0)

src/mountfsd/mountwork.c

@@ -158,16 +158,10 @@ static int validate_image_fd(int fd, MountImageParameters *p) {
         assert(fd >= 0);
         assert(p);
 
-        struct stat st;
-        if (fstat(fd, &st) < 0)
-                return -errno;
-        /* Only support regular files and block devices. Let's use stat_verify_regular() here for the nice
-         * error numbers it generates. */
-        if (!S_ISBLK(st.st_mode)) {
-                r = stat_verify_regular(&st);
-                if (r < 0)
-                        return r;
-        }
+        /* Only support regular files and block devices. */
+        r = fd_verify_regular_or_block(fd);
+        if (r < 0)
+                return r;
 
         fl = fd_verify_safe_flags_full(fd, O_NONBLOCK);
         if (fl < 0)

src/repart/repart.c

@@ -3226,26 +3226,6 @@ static int determine_current_padding(
         return 0;
 }
 
-static int verify_regular_or_block(int fd) {
-        struct stat st;
-
-        assert(fd >= 0);
-
-        if (fstat(fd, &st) < 0)
-                return -errno;
-
-        if (S_ISDIR(st.st_mode))
-                return -EISDIR;
-
-        if (S_ISLNK(st.st_mode))
-                return -ELOOP;
-
-        if (!S_ISREG(st.st_mode) && !S_ISBLK(st.st_mode))
-                return -EBADFD;
-
-        return 0;
-}
-
 static int context_copy_from_one(Context *context, const char *src) {
         _cleanup_close_ int fd = -EBADF;
         _cleanup_(fdisk_unref_contextp) struct fdisk_context *c = NULL;
@@ -3261,9 +3241,9 @@ static int context_copy_from_one(Context *context, const char *src) {
         if (r < 0)
                 return r;
 
-        r = verify_regular_or_block(fd);
+        r = fd_verify_regular_or_block(fd);
         if (r < 0)
-                return log_error_errno(r, "%s is not a file nor a block device: %m", src);
+                return log_error_errno(r, "'%s' is not a file nor a block device: %m", src);
 
         r = fdisk_new_context_at(fd, /* path= */ NULL, /* read_only= */ true, /* sector_size= */ UINT32_MAX, &c);
         if (r < 0)

src/shared/loop-util.c

@@ -820,7 +820,6 @@ int loop_device_make_by_path_memory(
 
         _cleanup_close_ int fd = -EBADF, mfd = -EBADF;
         _cleanup_free_ char *fn = NULL;
-        struct stat st;
         int r;
 
         assert(path);
@@ -837,11 +836,9 @@ int loop_device_make_by_path_memory(
         if (fd < 0)
                 return -errno;
 
-        if (fstat(fd, &st) < 0)
-                return -errno;
-
-        if (!S_ISREG(st.st_mode) && !S_ISBLK(st.st_mode))
-                return -EBADF;
+        r = fd_verify_regular_or_block(fd);
+        if (r < 0)
+                return r;
 
         r = path_extract_filename(path, &fn);
         if (r < 0)