tree-wide: warn when a directory path already exists but has bad mode/owner/type

When we are attempting to create directory somewhere in the bowels of /var/lib
and get an error that it already exists, it can be quite hard to diagnose what
is wrong (especially for a user who is not aware that the directory must have
the specified owner, and permissions not looser than what was requested). Let's
print a warning in most cases. A warning is appropriate, because such state is
usually a sign of borked installation and needs to be resolved by the adminstrator.

$ build/test-fs-util

Path "/tmp/test-readlink_and_make_absolute" already exists and is not a directory, refusing.
   (or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but has mode 0775 that is too permissive (0755 was requested), refusing.
   (or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but is owned by 1001:1000 (1000:1000 was requested), refusing.

Assertion 'mkdir_safe(tempdir, 0755, getuid(), getgid(), MKDIR_WARN_MODE) >= 0' failed at ../src/test/test-fs-util.c:320, function test_readlink_and_make_absolute(). Aborting.

No functional change except for the new log lines.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index daa4ab6a7..155ec6a5a 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -145,7 +145,7 @@ static int user_save_internal(User *u) {
         assert(u);
         assert(u->state_file);
 
-        r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, 0);
+        r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
         if (r < 0)
                 goto fail;
 
@@ -343,7 +343,7 @@ static int user_mkdir_runtime_path(User *u) {
 
         assert(u);
 
-        r = mkdir_safe_label("/run/user", 0755, 0, 0, 0);
+        r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE);
         if (r < 0)
                 return log_error_errno(r, "Failed to create /run/user: %m");