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[PATCH] link: work around IRIX bug
From: |
Eric Blake |
Subject: |
[PATCH] link: work around IRIX bug |
Date: |
Wed, 22 Jun 2011 12:42:46 -0600 |
On IRIX 6.5, link(file, "dangling") creates the target of dangling
as a link to file, rather than failing with EEXIST.
* m4/link.m4 (gl_FUNC_LINK): Expose the bug.
* lib/link.c (rpl_link): Work around it.
* tests/test-link.h (test_link): Enhance test.
* doc/posix-functions/link.texi (link): Document the bug.
Signed-off-by: Eric Blake <address@hidden>
---
ChangeLog | 6 ++++++
doc/posix-functions/link.texi | 4 ++++
lib/link.c | 17 +++++++++++++----
m4/link.m4 | 8 ++++++--
tests/test-link.h | 3 +++
5 files changed, 32 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 8ca76fa..440a244 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2011-06-22 Eric Blake <address@hidden>
+ link: work around IRIX bug
+ * m4/link.m4 (gl_FUNC_LINK): Expose the bug.
+ * lib/link.c (rpl_link): Work around it.
+ * tests/test-link.h (test_link): Enhance test.
+ * doc/posix-functions/link.texi (link): Document the bug.
+
getopt: silence clang warning
* lib/getopt.c (_getopt_internal_r): Avoid unlikely NULL
dereference.
diff --git a/doc/posix-functions/link.texi b/doc/posix-functions/link.texi
index 172037c..d4f2a7e 100644
--- a/doc/posix-functions/link.texi
+++ b/doc/posix-functions/link.texi
@@ -15,6 +15,10 @@ link
This function fails to reject trailing slashes on non-directories on
some platforms:
FreeBSD 7.2, Solaris 11 2010-11, Cygwin 1.5.x.
address@hidden
+When the second argument is a dangling symlink, some platforms follow
+that link and create the destination rather than failing:
+IRIX 6.5.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/lib/link.c b/lib/link.c
index 1b0fe0a..b58eb25 100644
--- a/lib/link.c
+++ b/lib/link.c
@@ -155,9 +155,20 @@ link (const char *file1, const char *file2)
int
rpl_link (char const *file1, char const *file2)
{
+ size_t len1;
+ size_t len2;
+ struct stat st;
+
+ /* Don't allow IRIX to dereference dangling file2 symlink. */
+ if (!lstat (file2, &st))
+ {
+ errno = EEXIST;
+ return -1;
+ }
+
/* Reject trailing slashes on non-directories. */
- size_t len1 = strlen (file1);
- size_t len2 = strlen (file2);
+ len1 = strlen (file1);
+ len2 = strlen (file2);
if ((len1 && file1[len1 - 1] == '/')
|| (len2 && file2[len2 - 1] == '/'))
{
@@ -165,7 +176,6 @@ rpl_link (char const *file1, char const *file2)
If stat() fails, then link() should fail for the same reason
(although on Solaris 9, link("file/","oops") mistakenly
succeeds); if stat() succeeds, require a directory. */
- struct stat st;
if (stat (file1, &st))
return -1;
if (!S_ISDIR (st.st_mode))
@@ -178,7 +188,6 @@ rpl_link (char const *file1, char const *file2)
{
/* Fix Cygwin 1.5.x bug where link("a","b/.") creates file "b". */
char *dir = strdup (file2);
- struct stat st;
char *p;
if (!dir)
return -1;
diff --git a/m4/link.m4 b/m4/link.m4
index 2f1a439..ed8427a 100644
--- a/m4/link.m4
+++ b/m4/link.m4
@@ -1,4 +1,4 @@
-# link.m4 serial 6
+# link.m4 serial 7
dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_LINK],
if test $ac_cv_func_link = no; then
HAVE_LINK=0
else
- AC_CACHE_CHECK([whether link handles trailing slash correctly],
+ AC_CACHE_CHECK([whether link obeys POSIX],
[gl_cv_func_link_works],
[touch conftest.a
# Assume that if we have lstat, we can also check symlinks.
@@ -28,6 +28,10 @@ AC_DEFUN([gl_FUNC_LINK],
#if HAVE_LSTAT
if (!link ("conftest.lnk/", "conftest.b"))
result |= 2;
+ if (rename ("conftest.a", "conftest.b"))
+ result |= 4;
+ if (!link ("conftest.b", "conftest.lnk"))
+ result |= 8;
#endif
return result;
]])],
diff --git a/tests/test-link.h b/tests/test-link.h
index 5e90951..5c50da0 100644
--- a/tests/test-link.h
+++ b/tests/test-link.h
@@ -166,6 +166,9 @@ test_link (int (*func) (char const *, char const *), bool
print)
ASSERT (func (BASE "b", BASE "link/") == -1);
ASSERT (errno == ENOTDIR || errno == ENOENT || errno == EEXIST
|| errno == EINVAL);
+ errno = 0;
+ ASSERT (func (BASE "b", BASE "link") == -1);
+ ASSERT (errno == EEXIST);
ASSERT (rename (BASE "b", BASE "a") == 0);
errno = 0;
ASSERT (func (BASE "link/", BASE "b") == -1);
--
1.7.4.4
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