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According to Eric Blake on 11/11/2009 6:21 AM:
> I also discovered that readlink is broken on FreeBSD:
>
> $ touch a
> $ ln -s a b
> $ ln -s b c
> $ readlink c/
> a => Oops - read the contents of b.
I'm pushing this for readlink.
- --
Don't work too hard, make some time for fun as well!
Eric Blake e...@byu.net
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>From dfd4d11c50dd4729bf46c26a3bbdda0c6031409d Mon Sep 17 00:00:00 2001
From: Eric Blake <e...@byu.net>
Date: Wed, 11 Nov 2009 06:34:02 -0700
Subject: [PATCH] readlink: detect FreeBSD bug
readlink("link-to-symlink/",buf,len) mistakenly read the contents
of "symlink", rather than failing.
* m4/readlink.m4 (gl_FUNC_READLINK): Also detect FreeBSD bug with
slash on symlink.
* doc/posix-functions/readlink.texi (readlink): Document the bug.
* tests/test-readlink.h (test_readlink): Enhance test.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 6 ++++++
doc/posix-functions/readlink.texi | 2 +-
m4/readlink.m4 | 7 +++++--
tests/test-readlink.h | 13 ++++++++++++-
4 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 227d9bd..fbfa1e4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2009-11-11 Eric Blake <e...@byu.net>
+ readlink: detect FreeBSD bug
+ * m4/readlink.m4 (gl_FUNC_READLINK): Also detect FreeBSD bug with
+ slash on symlink.
+ * doc/posix-functions/readlink.texi (readlink): Document the bug.
+ * tests/test-readlink.h (test_readlink): Enhance test.
+
symlink: detect FreeBSD bug
* m4/symlink.m4 (gl_FUNC_SYMLINK): Also detect FreeBSD bug with
slash on symlink.
diff --git a/doc/posix-functions/readlink.texi
b/doc/posix-functions/readlink.texi
index b1218f6..de898fb 100644
--- a/doc/posix-functions/readlink.texi
+++ b/doc/posix-functions/readlink.texi
@@ -10,7 +10,7 @@ readlink
@itemize
@item
Some platforms mistakenly succeed on @code{readlink("link/",buf,len)}:
-Solaris 9.
+FreeBSD 7.2, Solaris 9.
@item
On some platforms, @code{readlink} returns @code{int} instead of
@code{ssize_t}:
diff --git a/m4/readlink.m4 b/m4/readlink.m4
index fa7c2dd..e61c1a1 100644
--- a/m4/readlink.m4
+++ b/m4/readlink.m4
@@ -1,4 +1,4 @@
-# readlink.m4 serial 7
+# readlink.m4 serial 8
dnl Copyright (C) 2003, 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -21,15 +21,18 @@ AC_DEFUN([gl_FUNC_READLINK],
/* Cause compilation failure if original declaration has wrong type. */
ssize_t readlink (const char *, char *, size_t);]])],
[gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
+ dnl Solaris 9 ignores trailing slash.
+ dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
[gl_cv_func_readlink_works],
[# We have readlink, so assume ln -s works.
ln -s conftest.no-such conftest.link
+ ln -s conftest.link conftest.lnk2
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]], [[char buf[20];
- return readlink ("conftest.link/", buf, sizeof buf) != -1;]])],
+ return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
[gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
[gl_cv_func_readlink_works="guessing no"])
rm -f conftest.link])
diff --git a/tests/test-readlink.h b/tests/test-readlink.h
index 4ce67f7..5f5e910 100644
--- a/tests/test-readlink.h
+++ b/tests/test-readlink.h
@@ -52,11 +52,11 @@ test_readlink (ssize_t (*func) (char const *, char *,
size_t), bool print)
errno = 0;
ASSERT (func (BASE "file/", buf, sizeof buf) == -1);
ASSERT (errno == ENOTDIR);
- ASSERT (unlink (BASE "file") == 0);
/* Now test actual symlinks. */
if (symlink (BASE "dir", BASE "link"))
{
+ ASSERT (unlink (BASE "file") == 0);
if (print)
fputs ("skipping test: symlinks not supported on this file system\n",
stderr);
@@ -66,6 +66,17 @@ test_readlink (ssize_t (*func) (char const *, char *,
size_t), bool print)
errno = 0;
ASSERT (func (BASE "link/", buf, sizeof buf) == -1);
ASSERT (errno == EINVAL);
+ ASSERT (symlink (BASE "link", BASE "link2") == 0);
+ errno = 0;
+ ASSERT (func (BASE "link2/", buf, sizeof buf) == -1);
+ ASSERT (errno == EINVAL);
+ ASSERT (unlink (BASE "link2") == 0);
+ ASSERT (symlink (BASE "file", BASE "link2") == 0);
+ errno = 0;
+ ASSERT (func (BASE "link2/", buf, sizeof buf) == -1);
+ ASSERT (errno == ENOTDIR);
+ ASSERT (unlink (BASE "file") == 0);
+ ASSERT (unlink (BASE "link2") == 0);
{
/* Up till now, no readlink has been successful, so buf should be
unchanged. */
--
1.6.5.rc1
