[PATCH v3 2/3] sha1_file: open window into packfiles with O_CLOEXEC

[Junio C Hamano <gitster@pobox.com>]

From: Lars Schneider <larsxschneider@gmail.com>

All processes that the Git main process spawns inherit the open file
descriptors of the main process. These leaked file descriptors can
cause problems.

Use the O_CLOEXEC flag similar to 05d1ed61 to fix the leaked file
descriptors.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * And the remainder of original 1/2, again taking suggestion by DScho.

 sha1_file.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 5d2bcd3ed1..09045df1dc 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1561,7 +1561,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 
 int git_open(const char *name)
 {
-	static int sha1_file_open_flag = O_NOATIME;
+	static int sha1_file_open_flag = O_NOATIME | O_CLOEXEC;
 
 	for (;;) {
 		int fd;
@@ -1571,12 +1571,17 @@ int git_open(const char *name)
 		if (fd >= 0)
 			return fd;
 
-		/* Might the failure be due to O_NOATIME? */
-		if (errno != ENOENT && sha1_file_open_flag) {
-			sha1_file_open_flag = 0;
+		/* Try again w/o O_CLOEXEC: the kernel might not support it */
+		if ((sha1_file_open_flag & O_CLOEXEC) && errno == EINVAL) {
+			sha1_file_open_flag &= ~O_CLOEXEC;
 			continue;
 		}
 
+		/* Might the failure be due to O_NOATIME? */
+		if (errno != ENOENT && (sha1_file_open_flag & O_NOATIME)) {
+			sha1_file_open_flag &= ~O_NOATIME;
+			continue;
+		}
 		return -1;
 	}
 }
-- 
2.10.1-777-gd068e6bde7