git_open(): untangle possible NOATIME and CLOEXEC interactions

diff --git a/sha1_file.c b/sha1_file.c
index 5d2bcd3ed13cb2ca2a4645fdc968ed4580dcaf35..dfbf398183d5b9593b56c27b8cf5011d0ddd5e84 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1559,26 +1559,30 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
        return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-int git_open(const char *name)
+int git_open_cloexec(const char *name, int flags)
 {
-       static int sha1_file_open_flag = O_NOATIME;
-
-       for (;;) {
-               int fd;
+       static int cloexec = O_CLOEXEC;
+       int fd = open(name, flags | cloexec);
 
-               errno = 0;
-               fd = open(name, O_RDONLY | sha1_file_open_flag);
-               if (fd >= 0)
-                       return fd;
+       if ((cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
+               /* Try again w/o O_CLOEXEC: the kernel might not support it */
+               cloexec &= ~O_CLOEXEC;
+               fd = open(name, flags | cloexec);
+       }
+       return fd;
+}
 
-               /* Might the failure be due to O_NOATIME? */
-               if (errno != ENOENT && sha1_file_open_flag) {
-                       sha1_file_open_flag = 0;
-                       continue;
-               }
+int git_open(const char *name)
+{
+       static int noatime = O_NOATIME;
+       int fd = git_open_cloexec(name, O_RDONLY);
 
-               return -1;
+       if (0 <= fd && (noatime & O_NOATIME)) {
+               int flags = fcntl(fd, F_GETFL);
+               if (fcntl(fd, F_SETFL, flags | noatime))
+                       noatime = 0;
        }
+       return fd;
 }
 
 static int stat_sha1_file(const unsigned char *sha1, struct stat *st)