From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jiang Xin <worldhello.net@gmail.com>,
Lea Wiemann <lewiemann@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH 1/8] Introduce new static function real_path_internal()
Date: Sat, 29 Sep 2012 06:56:30 +0200 [thread overview]
Message-ID: <50667F7E.7040903@alum.mit.edu> (raw)
In-Reply-To: <7vk3vfp36g.fsf@alter.siamese.dyndns.org>
On 09/27/2012 11:27 PM, Junio C Hamano wrote:
> Michael Haggerty <mhagger@alum.mit.edu> writes:
>
>> @@ -54,20 +73,36 @@ const char *real_path(const char *path)
>> }
>>
>> if (*buf) {
>> - if (!*cwd && !getcwd(cwd, sizeof(cwd)))
>> - die_errno ("Could not get current working directory");
>> + if (!*cwd && !getcwd(cwd, sizeof(cwd))) {
>> + if (die_on_error)
>> + die_errno("Could not get current working directory");
>> + else
>> + goto error_out;
>> + }
>>
>> - if (chdir(buf))
>> - die_errno ("Could not switch to '%s'", buf);
>> + if (chdir(buf)) {
>> + if (die_on_error)
>> + die_errno("Could not switch to '%s'", buf);
>> + else
>> + goto error_out;
>> + }
>> + }
>
> The patch makes sense, but while you are touching this code, I have
> to wonder if there is an easy way to tell, before entering the loop,
> if we have to chdir() around in the loop. That would allow us to
> hoist the getcwd() that is done only so that we can come back to
> where we started outside the loop, making it clear why the call is
> there, instead of cryptic "if (!*cwd &&" to ensure we do getcwd()
> once and before doing any chdir().
I don't see an easy way to predict, before entering the loop, whether
chdir() will be needed. For example, compare
touch filename
ln -s filename foo
./test-path-utils real_path foo
with
touch filename
ln -s $(pwd)/filename foo
./test-path-utils real_path foo
In the first case no chdir() is needed, whereas in the second case a
chdir() is needed but only on the second loop iteration.
All I can offer you is a palliative like the one below.
Michael
diff --git a/abspath.c b/abspath.c
index 5748b91..40cdc46 100644
--- a/abspath.c
+++ b/abspath.c
@@ -35,7 +35,14 @@ static const char *real_path_internal(const char
*path, int die_on_error)
{
static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf =
bufs[1];
char *retval = NULL;
+
+ /*
+ * If we have to temporarily chdir(), store the original CWD
+ * here so that we can chdir() back to it at the end of the
+ * function:
+ */
char cwd[1024] = "";
+
int buf_index = 1;
int depth = MAXDEPTH;
--
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/
next prev parent reply other threads:[~2012-09-29 4:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-24 8:00 [PATCH] test: some testcases failed if cwd is on a symlink Jiang Xin
2012-07-24 8:24 ` Stefano Lattarini
2012-07-24 10:59 ` Pete Wyckoff
2012-07-24 14:47 ` Junio C Hamano
2012-07-24 22:06 ` Jiang Xin
2012-08-18 14:41 ` Michael Haggerty
2012-08-18 20:36 ` Junio C Hamano
2012-08-19 13:57 ` Michael Haggerty
2012-08-19 16:43 ` Junio C Hamano
2012-08-21 5:59 ` Michael Haggerty
2012-08-27 5:13 ` [PATCH v2] test: set the realpath of CWD as TRASH_DIRECTORY Jiang Xin
2012-08-27 16:15 ` Junio C Hamano
2012-08-29 4:14 ` Michael Haggerty
2012-08-29 6:06 ` Junio C Hamano
2012-08-29 8:15 ` Michael Haggerty
2012-08-29 16:33 ` Junio C Hamano
2012-08-30 4:37 ` Michael Haggerty
2012-08-30 5:26 ` Junio C Hamano
2012-08-31 7:49 ` Michael Haggerty
2012-09-26 19:34 ` [PATCH 0/8] Fix GIT_CEILING_DIRECTORIES that contain symlinks Michael Haggerty
2012-09-26 19:34 ` [PATCH 1/8] Introduce new static function real_path_internal() Michael Haggerty
2012-09-27 21:27 ` Junio C Hamano
2012-09-29 4:56 ` Michael Haggerty [this message]
2012-09-29 5:40 ` Junio C Hamano
2012-09-26 19:34 ` [PATCH 2/8] Introduce new function real_path_if_valid() Michael Haggerty
2012-09-26 19:34 ` [PATCH 3/8] longest_ancestor_length(): use string_list_split() Michael Haggerty
2012-09-27 22:48 ` Junio C Hamano
2012-09-29 5:25 ` Michael Haggerty
2012-09-29 5:43 ` Junio C Hamano
2012-09-26 19:34 ` [PATCH 4/8] longest_ancestor_length(): explicitly filter list before loop Michael Haggerty
2012-09-27 22:48 ` Junio C Hamano
2012-09-26 19:34 ` [PATCH 5/8] longest_ancestor_length(): always add a slash to the end of prefixes Michael Haggerty
2012-09-26 19:34 ` [PATCH 6/8] longest_ancestor_length(): use string_list_longest_prefix() Michael Haggerty
2012-09-26 19:34 ` [PATCH 7/8] longest_ancestor_length(): resolve symlinks before comparing paths Michael Haggerty
2012-09-27 22:51 ` Junio C Hamano
2012-09-29 5:46 ` Michael Haggerty
2012-09-26 19:34 ` [PATCH 8/8] t1504: stop resolving symlinks in GIT_CEILING_DIRECTORIES Michael Haggerty
2012-09-27 19:42 ` [PATCH 0/8] Fix GIT_CEILING_DIRECTORIES that contain symlinks Junio C Hamano
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