Re: [PATCH 1/2] config: check if config path is a file before parsing it

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 3, 2017, 21:05 UTC
Message-ID: <xmqq4lza840k.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20170303095351.rgifjpfuvafx33jy@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

>        a. actually check ferror() after getting EOF and report the read
>           error. That catches EISDIR, along with any other unexpected
> 	  errors.

That is the most sensible, I would think (assuming that we really get EISDIR instead of silent EOF).

>        b. use an fopen wrapper that checks fstat(fileno(fh)) after the
>           open, and turns fopen(some_dir) into an error.

That's already an option with FREAD_READS_DIRECTORIES, I think.

Show 5 quoted lines

>   2. It doesn't address the root problem for git_config_from_file(),
>      which is that it is quiet when fopen fails, even if the reason is
>      something interesting besides ENOENT. The caller can't check errno
>      because it doesn't know if fopen() failed, or if the config
>      callback returned an error.

Perhaps like this one as a starting point, with FREAD_READS_DIRECTORIES?

 config.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/config.c b/config.c
index 0dac0f4cb2..af8c01c8a3 100644
--- a/config.c
+++ b/config.c
@@ -1305,6 +1305,9 @@ int git_config_from_file(config_fn_t fn, const char *filename, void *data)
 	FILE *f;
 
 	f = fopen(filename, "r");
+	if (!f && errno != ENOENT)
+		die_errno("fopen('%s') failed", filename);
+
 	if (f) {
 		flockfile(f);
 		ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename, filename, f, data);