Merge branch 'jh/rlimit-nofile-fallback' into maint

When we figure out how many file descriptors to allocate for
keeping packfiles open, a system with non-working getrlimit() could
cause us to die(), but because we make this call only to get a
rough estimate of how many is available and we do not even attempt
to use up all file descriptors available ourselves, it is nicer to
fall back to a reasonable low value rather than dying.

* jh/rlimit-nofile-fallback:
get_max_fd_limit(): fall back to OPEN_MAX upon getrlimit/sysconf failure

diff --git a/sha1_file.c b/sha1_file.c
index 760dd60031bc4de7f0155303da5938c1571a2378..06c809aeeb3a608c09247b4f2146eb246938d6bf 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -807,15 +807,38 @@ void free_pack_by_name(const char *pack_name)
 static unsigned int get_max_fd_limit(void)
 {
 #ifdef RLIMIT_NOFILE
-       struct rlimit lim;
+       {
+               struct rlimit lim;
 
-       if (getrlimit(RLIMIT_NOFILE, &lim))
-               die_errno("cannot get RLIMIT_NOFILE");
+               if (!getrlimit(RLIMIT_NOFILE, &lim))
+                       return lim.rlim_cur;
+       }
+#endif
+
+#ifdef _SC_OPEN_MAX
+       {
+               long open_max = sysconf(_SC_OPEN_MAX);
+               if (0 < open_max)
+                       return open_max;
+               /*
+                * Otherwise, we got -1 for one of the two
+                * reasons:
+                *
+                * (1) sysconf() did not understand _SC_OPEN_MAX
+                *     and signaled an error with -1; or
+                * (2) sysconf() said there is no limit.
+                *
+                * We _could_ clear errno before calling sysconf() to
+                * tell these two cases apart and return a huge number
+                * in the latter case to let the caller cap it to a
+                * value that is not so selfish, but letting the
+                * fallback OPEN_MAX codepath take care of these cases
+                * is a lot simpler.
+                */
+       }
+#endif
 
-       return lim.rlim_cur;
-#elif defined(_SC_OPEN_MAX)
-       return sysconf(_SC_OPEN_MAX);
-#elif defined(OPEN_MAX)
+#ifdef OPEN_MAX
        return OPEN_MAX;
 #else
        return 1; /* see the caller ;-) */