Re: areadlinkat

[Eric Blake]

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According to Eric Blake on 10/21/2009 9:33 PM:
>> +    * lib/at-func.c (FUNC_FAIL): New define.
>> +    (AT_FUNC_NAME, VALIDATE_FLAG): Use it rather than raw -1.
> 
> Oops - I missed one instance relating to FUNC_FAIL.  test-areadlinkat was
> failing on older Linux, because /proc/self/fd/-1/name gave ENOENT rather
> than EBADF.  But since 0 <= char* was always true, the fallback code that
> converts ENOENT into the correct error was never triggered.
> areadlinkat-with-size was the only other impacted client of at-func.c.

And yet one more instance, this time caught by gcc warnings, but harder to
trigger in code.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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>From 185233aa304e916609398bc9539029c01805b4d6 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Mon, 26 Oct 2009 21:41:21 -0600
Subject: [PATCH] areadlinkat: fix fallback path

* lib/at-func.c (AT_FUNC_NAME): Avoid signed comparison between
pointer and zero.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog     |    6 ++++++
 lib/at-func.c |    2 +-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e2f8551..0897109 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-10-26  Eric Blake  <address@hidden>
+
+       areadlinkat: fix fallback path
+       * lib/at-func.c (AT_FUNC_NAME): Avoid signed comparison between
+       pointer and zero.
+
 2009-10-22  Pádraig Brady  <address@hidden>

        Use a better IO block size for modern systems
diff --git a/lib/at-func.c b/lib/at-func.c
index cc7bfc2..73be401 100644
--- a/lib/at-func.c
+++ b/lib/at-func.c
@@ -115,7 +115,7 @@ AT_FUNC_NAME (int fd, char const *file 
AT_FUNC_POST_FILE_PARAM_DECLS)
     }

   err = CALL_FUNC (file);
-  saved_errno = (err < 0 ? errno : 0);
+  saved_errno = (err == FUNC_FAIL ? errno : 0);

   if (restore_cwd (&saved_cwd) != 0)
     openat_restore_fail (errno);
-- 
1.6.5.rc1