[PATCH 02/20] safe_create_leading_directories(): set errno on SCLD_EXISTS

From

Michael Haggerty <mhagger@alum.mit.edu>

Date

Feb 16, 2016, 13:22 UTC

Message-ID

<7ddc8ac89f36b01494fbdc6f97bf1ca258b3e885.1455626201.git.mhagger@alum.mit.edu>

In-Reply-To

<cover.1455626201.git.mhagger@alum.mit.edu>

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 cache.h     | 10 ++++++++--
 sha1_file.c |  4 +++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/cache.h b/cache.h
index 26640b4..7d3f80c 100644
--- a/cache.h
+++ b/cache.h
@@ -950,8 +950,9 @@ 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
@@ -959,6 +960,11 @@ int adjust_shared_perm(const char *path);
  * directory while we were working.  To be robust against this kind of
  * race, callers might want to try invoking the function again when it
  * returns SCLD_VANISHED.
+ *
+ * The non _const version of this function temporarily modifies its
+ * path parameter while it is working but restores it before exiting.
+ * The _const version does not modify path (at the cost of having to
+ * make a temporary scratch copy).
  */
 enum scld_error {
 	SCLD_OK = 0,
diff --git a/sha1_file.c b/sha1_file.c
index 568120e..a1ac646 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -135,8 +135,10 @@ 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 = EEXIST;
 				ret = SCLD_EXISTS;
+			}
 		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
 			    !stat(path, &st) && S_ISDIR(st.st_mode))

-- 
2.7.0