On 12/27/2013 12:35 PM, Pádraig Brady wrote:
> On 12/27/2013 12:31 PM, Pádraig Brady wrote:
>> This is a bug and happens when ln tries to determine of the last arg is a
>> directory.
>> It does a stat(2) which gives this error. ENOENT is specifically ignored,
>> but it
>> seems like others should be too. You can see the source of the error with:
>>
>> $ stat -L len256
>> stat: cannot stat `len256': File name too long
>>
>> When resetting symlinks to point to somewhere else I always use -nsf
>> and that does avoid the issue here too.
>
> Note the 255 limit probably comes from:
>
> $ getconf NAME_MAX .
> 255
I'll push the attached soon to fix this.
thanks,
Pádraig.
>From 672b0b5f1023f7f433973edec7376fce330cb2a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <p...@draigbrady.com>
Date: Fri, 17 Jan 2014 03:54:29 +0000
Subject: [PATCH] ln: fix replacing symbolic links whose targets can't exist
* src/ln.c (errno_nonexisting): A new function to determine if
the errno implies that a file doesn't or can't (currently) exist.
(target_directory_operand): Use the new function to expand the
set of errors we handle.
* tests/ln/sf-1.sh: Add test cases for the newly handled errors.
* THANKS.in: Mention the reporter.
* NEWS: Mention the bug fix.
---
NEWS | 4 ++++
THANKS.in | 1 +
src/ln.c | 14 ++++++++++++--
tests/ln/sf-1.sh | 16 +++++++++++++++-
4 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/NEWS b/NEWS
index 699a7d3..88a4154 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,10 @@ GNU coreutils NEWS -*- outline -*-
when reading the SELinux context for a file.
[bug introduced in coreutils-8.22]
+ ln -sf now replaces symbolic links whose targets can't exist. Previously
+ it would display an error, requiring --no-dereference to avoid the issue.
+ [bug introduced in coreutils-5.3.0]
+
* Noteworthy changes in release 8.22 (2013-12-13) [stable]
diff --git a/THANKS.in b/THANKS.in
index 5b3e96e..fb7d6e0 100644
--- a/THANKS.in
+++ b/THANKS.in
@@ -341,6 +341,7 @@ Kaveh R. Ghazi gh...@caip.rutgers.edu
Keith M. Briggs keith.bri...@bt.com
Keith Owens k...@audio.apana.org.au
Keith Thompson k...@cts.com
+Ken Irving ken.irv...@alaska.edu
Ken Pizzini k...@halcyon.com
Kevin Mudrick kmudr...@healthmarketscience.com
Kirk Kelsey kirk.kel...@0x4b.net
diff --git a/src/ln.c b/src/ln.c
index b490362..aab9cf2 100644
--- a/src/ln.c
+++ b/src/ln.c
@@ -103,8 +103,18 @@ static struct option const long_options[] =
{NULL, 0, NULL, 0}
};
+/* Return true when the passed ERR implies
+ that a file does not or could not exist. */
+
+static bool
+errno_nonexisting (int err)
+{
+ return err == ENOENT || err == ENAMETOOLONG || err == ENOTDIR || err == ELOOP;
+}
+
+
/* FILE is the last operand of this command. Return true if FILE is a
- directory. But report an error there is a problem accessing FILE,
+ directory. But report an error if there is a problem accessing FILE,
or if FILE does not exist but would have to refer to an existing
directory if it referred to anything at all. */
@@ -119,7 +129,7 @@ target_directory_operand (char const *file)
(dereference_dest_dir_symlinks ? stat (file, &st) : lstat (file, &st));
int err = (stat_result == 0 ? 0 : errno);
bool is_a_dir = !err && S_ISDIR (st.st_mode);
- if (err && err != ENOENT)
+ if (err && ! errno_nonexisting (errno))
error (EXIT_FAILURE, err, _("failed to access %s"), quote (file));
if (is_a_dir < looks_like_a_dir)
error (EXIT_FAILURE, err, _("target %s is not a directory"), quote (file));
diff --git a/tests/ln/sf-1.sh b/tests/ln/sf-1.sh
index 3f4f8f1..ecf3aae 100755
--- a/tests/ln/sf-1.sh
+++ b/tests/ln/sf-1.sh
@@ -20,12 +20,26 @@
print_ver_ ln
echo foo > a || framework_failure_
-ln -s . b || framework_failure_
+# Check that a target directory of '.' is supported
+# and that indirectly specifying the same target and link name
+# through that is detected.
+ln -s . b || framework_failure_
ln -sf a b > err 2>&1 && fail=1
case $(cat err) in
*'are the same file') ;;
*) fail=1 ;;
esac
+# Ensure we replace symlinks that don't or can't link to an existing target.
+# coreutils-8.22 would fail to replace {ENOTDIR,ELOOP,ENAMETOOLONG}_link below.
+name_max_plus1=$(expr $(stat -f -c %l .) + 1)
+long_name=$(printf '%0*d' $name_max_plus1 0)
+for f in '' f; do
+ ln -s$f missing ENOENT_link || fail=1
+ ln -s$f a/b ENOTDIR_link || fail=1
+ ln -s$f ELOOP_link ELOOP_link || fail=1
+ ln -s$f "$long_name" ENAMETOOLONG_link || fail=1
+done
+
Exit $fail
--
1.7.7.6
