[PATCH v4 05/23] safe_create_leading_directories(): set errno on SCLD_EXISTS

[Michael Haggerty <mhagger@alum.mit.edu>]

The exit path for SCLD_EXISTS wasn't setting errno, which some callers
use to generate error messages for the user. Fix the problem and
document that the function sets errno correctly to help avoid similar
regressions in the future.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 cache.h     | 5 +++--
 sha1_file.c | 4 +++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/cache.h b/cache.h
index a50a61a..8177c3a 100644
--- a/cache.h
+++ b/cache.h
@@ -1031,8 +1031,9 @@ int adjust_shared_perm(const char *path);
 
 /*
  * Create the directory containing the named path, using care to be
- * somewhat safe against races.  Return one of the scld_error values
- * to indicate success/failure.
+ * somewhat safe against races. Return one of the scld_error values to
+ * indicate success/failure. On error, set errno to describe the
+ * problem.
  *
  * SCLD_VANISHED indicates that one of the ancestor directories of the
  * path existed at one point during the function call and then
diff --git a/sha1_file.c b/sha1_file.c
index 10395e7..ae8f0b4 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -137,8 +137,10 @@ enum scld_error safe_create_leading_directories(char *path)
 		*slash = '\0';
 		if (!stat(path, &st)) {
 			/* path exists */
-			if (!S_ISDIR(st.st_mode))
+			if (!S_ISDIR(st.st_mode)) {
+				errno = ENOTDIR;
 				ret = SCLD_EXISTS;
+			}
 		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
 			    !stat(path, &st) && S_ISDIR(st.st_mode))
-- 
2.9.3