git_open(): untangle possible NOATIME and CLOEXEC interactions

diff --git a/sha1_file.c b/sha1_file.c
index 266152de36a099bfa75bfaa8429f0234c52a80b1..dfbf398183d5b9593b56c27b8cf5011d0ddd5e84 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -370,7 +370,7 @@ void read_info_alternates(const char * relative_base, int depth)
        int fd;
 
        path = xstrfmt("%s/info/alternates", relative_base);
-       fd = git_open_noatime(path);
+       fd = git_open(path);
        free(path);
        if (fd < 0)
                return;
@@ -663,7 +663,7 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
        struct pack_idx_header *hdr;
        size_t idx_size;
        uint32_t version, nr, i, *index;
-       int fd = git_open_noatime(path);
+       int fd = git_open(path);
        struct stat st;
 
        if (fd < 0)
@@ -1069,7 +1069,7 @@ static int open_packed_git_1(struct packed_git *p)
        while (pack_max_fds <= pack_open_fds && close_one_pack())
                ; /* nothing */
 
-       p->pack_fd = git_open_noatime(p->pack_name);
+       p->pack_fd = git_open(p->pack_name);
        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
                return -1;
        pack_open_fds++;
@@ -1559,26 +1559,30 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
        return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-int git_open_noatime(const char *name)
+int git_open_cloexec(const char *name, int flags)
 {
-       static int sha1_file_open_flag = O_NOATIME;
+       static int cloexec = O_CLOEXEC;
+       int fd = open(name, flags | cloexec);
 
-       for (;;) {
-               int fd;
-
-               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)
@@ -1605,7 +1609,7 @@ static int open_sha1_file(const unsigned char *sha1)
        struct alternate_object_database *alt;
        int most_interesting_errno;
 
-       fd = git_open_noatime(sha1_file_name(sha1));
+       fd = git_open(sha1_file_name(sha1));
        if (fd >= 0)
                return fd;
        most_interesting_errno = errno;
@@ -1613,7 +1617,7 @@ static int open_sha1_file(const unsigned char *sha1)
        prepare_alt_odb();
        for (alt = alt_odb_list; alt; alt = alt->next) {
                const char *path = alt_sha1_path(alt, sha1);
-               fd = git_open_noatime(path);
+               fd = git_open(path);
                if (fd >= 0)
                        return fd;
                if (most_interesting_errno == ENOENT)