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Re: [PATCH v2 06/10] setup_git_env: use git_pathdup instead of xmalloc + sprintf

From
Junio C Hamano <gitster@pobox.com>
Date
Jun 25, 2014, 17:20 UTC
Message-ID
<xmqqmwd0aotu.fsf@gitster.dls.corp.google.com>
In-Reply-To
<20140624205815.GA28724@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 13 quoted lines
> Here's a replacement patch that handles this (and just drops the ugly
> mallocs as a side effect).
>
> -- >8 --
> Subject: [PATCH] setup_git_env: copy getenv return value
>
> The return value of getenv is not guaranteed to survive
> across further invocations of setenv or even getenv. When we
> are assigning it to globals that last the lifetime of the
> program, we should make our own copy.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---

Sigh. This mail unfortunately crossed with 64f25581 (Merge branch 'jk/xstrfmt' into next, 2014-06-23) with about 20 hours of lag.

I'd make it relative like the attached on top of the series. Note that I tweaked the args to git_pathdup() to avoid the "are you sure you want to give a variable format string to git_pathdup() which you said is like printf(3)?" warning from the compiler.

Thanks.
-- >8 --
From: Jeff King <peff@peff.net>
Date: Tue, 24 Jun 2014 16:58:15 -0400
Subject: [PATCH] setup_git_env(): introduce git_path_from_env() helper

"Check the value of an environment and fall back to a known path inside $GIT_DIR" is repeated a few times to determine the location of the data store, the index and the graft file, but the return value of getenv is not guaranteed to survive across further invocations of setenv or even getenv.

Make sure to xstrdup() the value we receive from getenv(3), and encapsulate the pattern into a helper function.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 environment.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/environment.c b/environment.c
index 4de7b81..565f652 100644
--- a/environment.c
+++ b/environment.c
@@ -124,6 +124,12 @@ static char *expand_namespace(const char *raw_namespace)
 	return strbuf_detach(&buf, NULL);
 }
 
+static char *git_path_from_env(const char *envvar, const char *path)
+{
+	const char *value = getenv(envvar);
+	return value ? xstrdup(value) : git_pathdup("%s", path);
+}
+
 static void setup_git_env(void)
 {
 	const char *gitfile;
@@ -134,15 +140,9 @@ static void setup_git_env(void)
 		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
 	gitfile = read_gitfile(git_dir);
 	git_dir = xstrdup(gitfile ? gitfile : git_dir);
-	git_object_dir = getenv(DB_ENVIRONMENT);
-	if (!git_object_dir)
-		git_object_dir = git_pathdup("objects");
-	git_index_file = getenv(INDEX_ENVIRONMENT);
-	if (!git_index_file)
-		git_index_file = git_pathdup("index");
-	git_graft_file = getenv(GRAFT_ENVIRONMENT);
-	if (!git_graft_file)
-		git_graft_file = git_pathdup("info/grafts");
+	git_object_dir = git_path_from_env(DB_ENVIRONMENT, "objects");
+	git_index_file = git_path_from_env(INDEX_ENVIRONMENT, "index");
+	git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, "info/grafts");
 	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
 		check_replace_refs = 0;
 	namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
-- 
2.0.0-641-g934bf98
Previous: Duy NguyenNext: Jeff King
Message 19 of 27 in “dropping manual malloc calculations”
  1. 0/2 dropping manual malloc calculationsJeff King, Jun 18, 2014
  2. 1/2 strbuf: add xstrdup_fmt helperJeff King, Jun 18, 2014
  3. Junio C HamanoJun 18, 2014
  4. Jeff KingJun 19, 2014
  5. Junio C HamanoJun 19, 2014
  6. dropping manual malloc calculationsJeff King, Jun 19, 2014
  7. 01/10 strbuf: add xstrfmt helperJeff King, Jun 19, 2014
  8. 02/10 use xstrfmt in favor of manual size calculationsJeff King, Jun 19, 2014
  9. 03/10 use xstrdup instead of xmalloc + strcpyJeff King, Jun 19, 2014
  10. 04/10 use xstrfmt to replace xmalloc + sprintfJeff King, Jun 19, 2014
  11. 05/10 use xstrfmt to replace xmalloc + strcpy/strcatJeff King, Jun 19, 2014
  12. 06/10 setup_git_env: use git_pathdup instead of xmalloc + sprintfJeff King, Jun 19, 2014
  13. Eric SunshineJun 23, 2014
  14. Junio C HamanoJun 23, 2014
  15. Duy NguyenJun 24, 2014
  16. Duy NguyenJun 24, 2014
  17. Jeff KingJun 24, 2014
  18. Duy NguyenJun 25, 2014
  19. Junio C HamanoJun 25, 2014
  20. Jeff KingJun 25, 2014
  21. Junio C HamanoJun 25, 2014
  22. 07/10 sequencer: use argv_array_pushfJeff King, Jun 19, 2014
  23. 08/10 merge: use argv_array when spawning merge strategyJeff King, Jun 19, 2014
  24. 09/10 walker_fetch: fix minor memory leakJeff King, Jun 19, 2014
  25. 10/10 unique_path: fix unlikely heap overflowJeff King, Jun 19, 2014
  26. René ScharfeJun 19, 2014
  27. 2/2 use xstrdup_fmt in favor of manual size calculationsJeff King, Jun 18, 2014

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