opt: Don't raise RLIMIT_NOFILE if it would prevent using posix_spawn()

If we raise RLIMIT_NOFILE, we have to lower it before calling exec() for
compatibility with select().  If posix_spawn() doesn't support that, we
fall back to fork(), which is quite a bit slower.

Therefore, if we're going to exec() on most files, it's better to keep
RLIMIT_NOFILE the same to avoid the fork() cost, even though it makes
bftw() somewhat slower.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/ctx.h b/src/ctx.h
index fc3020c..b28a63c 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -102,6 +102,8 @@ struct bfs_ctx {
 	struct rlimit orig_nofile;
 	/** The current RLIMIT_NOFILE limits. */
 	struct rlimit cur_nofile;
+	/** Whether the fd limit should be raised. */
+	bool raise_nofile;
 
 	/** The current time. */
 	struct timespec now;