undef/git-commit-vandalism
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

config: move flockfile() closer to unlocked functions

Browse Source 
Commit 260d408e32 (config: use getc_unlocked when reading
from file, 2015-04-16) taught git_config_from_file() to lock
the filehandle so that we could safely use the faster
unlocked functions to access the handle.

However, it split the logic into two places:

  1. The master lock/unlock happens in git_config_from_file().

  2. The decision to use the unlocked functions happens in
     do_config_from_file().

That means that if anybody calls the latter function, they
will accidentally use the unlocked functions without holding
the lock. And indeed, git_config_from_stdin() does so.

In practice, this hasn't been a problem since this code
isn't generally multi-threaded (and even if some Git program
happened to have another thread running, it's unlikely to be
reading from stdin). But it's a good practice to make sure
we're always holding the lock before using the unlocked
functions.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2018-03-30 15:26:15 -04:00 committed by Junio C Hamano
parent 3013dff866
commit 05e293c1ac
1 changed files with 5 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
config.c
View File

@ -1408,6 +1408,7 @@ static int do_config_from_file(config_fn_t fn,
void *data)
{
struct config_source top;
int ret;
top.u.file = f;
top.origin_type = origin_type;
@ -1418,7 +1419,10 @@ static int do_config_from_file(config_fn_t fn,
top.do_ungetc = config_file_ungetc;
top.do_ftell = config_file_ftell;
return do_config_from(&top, fn, data);
flockfile(f);
ret = do_config_from(&top, fn, data);
funlockfile(f);
return ret;
}
static int git_config_from_stdin(config_fn_t fn, void *data)
@ -1433,9 +1437,7 @@ int git_config_from_file(config_fn_t fn, const char *filename, void *data)
f = fopen_or_warn(filename, "r");
if (f) {
flockfile(f);
ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename, filename, f, data);
funlockfile(f);
fclose(f);
}
return ret;