path-util: rework find_binary(), fsck_exists() and mkfs_exists()

Modernize the code a bit:

- Get rid of FOREACH_WORD_SEPARATOR() loop in favour of a
  extract_first_word() loop.

- Remove find_binary()'s "local" flag. It's not reasonably possible to
  look for binaries on remote systems, we hence should not pretend we
  could.

- When we cannot find a suitable binary, return the last error returned
  from access() rather than ENOENT unconditionally.

- Rework fsck_exists() and mkfs_exists() to return 1 on success, 0 if
  the implementation is missing and negative on real errors. This is
  more like we do it in other functions.

- Make sure we also detect direct fsck symlinks to "true", rather than
  just absolute ones to /bin/true.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/shared/generator.c b/src/shared/generator.c
index e58bbea77c..d912bcd9e1 100644
--- a/src/shared/generator.c
+++ b/src/shared/generator.c
@@ -32,10 +32,9 @@
 #include "dropin.h"
 
 static int write_fsck_sysroot_service(const char *dir, const char *what) {
-        const char *unit;
-        _cleanup_free_ char *device = NULL;
-        _cleanup_free_ char *escaped;
+        _cleanup_free_ char *device = NULL, *escaped = NULL;
         _cleanup_fclose_ FILE *f = NULL;
+        const char *unit;
         int r;
 
         escaped = cescape(what);
@@ -101,16 +100,17 @@ int generator_write_fsck_deps(
 
         if (!isempty(fstype) && !streq(fstype, "auto")) {
                 r = fsck_exists(fstype);
-                if (r == -ENOENT) {
+                if (r < 0)
+                        log_warning_errno(r, "Checking was requested for %s, but couldn't detect if fsck.%s may be used, proceeding: %m", what, fstype);
+                else if (r == 0) {
                         /* treat missing check as essentially OK */
-                        log_debug_errno(r, "Checking was requested for %s, but fsck.%s does not exist: %m", what, fstype);
+                        log_debug("Checking was requested for %s, but fsck.%s does not exist.", what, fstype);
                         return 0;
-                } else if (r < 0)
-                        return log_warning_errno(r, "Checking was requested for %s, but fsck.%s cannot be used: %m", what, fstype);
+                }
         }
 
         if (path_equal(where, "/")) {
-                char *lnk;
+                const char *lnk;
 
                 lnk = strjoina(dir, "/" SPECIAL_LOCAL_FS_TARGET ".wants/systemd-fsck-root.service");