Re: [PATCH] ls: print "?", not "0" as inode of dereferenced dangling symlink

[Jim Meyering]

Jim Meyering wrote:
> Here's another corner-case fix.
> I'll push something like this as soon as I've updated NEWS
> and added a test.
>
>>From 26a1306a0a9028eceed388dad0d8916aeeb00233 Mon Sep 17 00:00:00 2001
> From: Jim Meyering <address@hidden>
> Date: Mon, 28 Sep 2009 20:24:41 +0200

Here's a more complete patch, though I still have
to add a mention in NEWS about the origin.


>From f4d682808c6c8d2e1871278f3e81d0d0766f792b Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Mon, 28 Sep 2009 20:24:41 +0200
Subject: [PATCH] ls: print "?", not "0" as inode of dereferenced dangling 
symlink

ls prints inode numbers two ways: for long (-l) listings,
and for short ones, e.g., ls -li and ls -i.  The code to print
long listings properly printed "?" when the inode was unknown,
but the code for handling short listings would print 0 instead.
Factor out the formatting code into a new function so ls prints
the right string ("?") from both places:
* NEWS (Bug fixes): Mention it.
* src/ls.c (format_inode): New function.
(print_long_format): Use it here.
(print_file_name_and_frills): Use it here, too.
* tests/ls/dangle: Exercise this fix.
Reported by Yang Ren in http://bugzilla.redhat.com/525400
---
 NEWS            |    8 ++++++++
 src/ls.c        |   18 +++++++++++++-----
 tests/ls/dangle |    8 ++++++++
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index d0a9a7d..1a0c847 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,14 @@ GNU coreutils NEWS                                    -*- 
outline -*-

   ls -LR exits with status 2, not 0, when it encounters a cycle

+  ls -L now print "?", not "0" as the inode of a dangling symlink.
+  For example, before, "mkdir d; ln -s no-such d/s; ls -Li d" would print
+    ls: cannot access d/s: No such file or directory
+    0 s
+  now it prints this:
+    ls: cannot access d/s: No such file or directory
+    ? s
+
 ** Portability

   On Solaris 9, many commands would mistakenly treat file/ the same as
diff --git a/src/ls.c b/src/ls.c
index 86f5c32..c8e8abb 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -3556,9 +3556,19 @@ format_group_width (gid_t g)
   return format_user_or_group_width (numeric_ids ? NULL : getgroup (g), g);
 }

+/* Return a pointer to a formatted version of F->stat.st_ino,
+   possibly using buffer, BUF, of length BUFLEN, which must be at least
+   INT_BUFSIZE_BOUND (uintmax_t) bytes.  */
+static char *
+format_inode (char *buf, size_t buflen, const struct fileinfo *f)
+{
+  assert (INT_BUFSIZE_BOUND (uintmax_t) <= buflen);
+  return (f->stat.st_ino == NOT_AN_INODE_NUMBER
+          ? (char *) "?"
+          : umaxtostr (f->stat.st_ino, buf));
+}

 /* Print information about F in long format.  */
-
 static void
 print_long_format (const struct fileinfo *f)
 {
@@ -3615,9 +3625,7 @@ print_long_format (const struct fileinfo *f)
     {
       char hbuf[INT_BUFSIZE_BOUND (uintmax_t)];
       sprintf (p, "%*s ", inode_number_width,
-               (f->stat.st_ino == NOT_AN_INODE_NUMBER
-                ? "?"
-                : umaxtostr (f->stat.st_ino, hbuf)));
+               format_inode (hbuf, sizeof hbuf, f));
       /* Increment by strlen (p) here, rather than by inode_number_width + 1.
          The latter is wrong when inode_number_width is zero.  */
       p += strlen (p);
@@ -4004,7 +4012,7 @@ print_file_name_and_frills (const struct fileinfo *f, 
size_t start_col)

   if (print_inode)
     printf ("%*s ", format == with_commas ? 0 : inode_number_width,
-            umaxtostr (f->stat.st_ino, buf));
+            format_inode (buf, sizeof buf, f));

   if (print_block_size)
     printf ("%*s ", format == with_commas ? 0 : block_size_width,
diff --git a/tests/ls/dangle b/tests/ls/dangle
index b2f8539..6abad92 100755
--- a/tests/ls/dangle
+++ b/tests/ls/dangle
@@ -26,6 +26,9 @@ fi
 ln -s no-such-file dangle || framework_failure
 mkdir -p dir/sub || framework_failure
 ln -s dir slink-to-dir || framework_failure
+mkdir d || framework_failure
+ln -s no-such d/dangle || framework_failure
+echo '? dangle' > subdir_exp || framework_failure

 fail=0

@@ -50,4 +53,9 @@ EOF

 compare out exp || fail=1

+# Ensure that ls -Li prints "?" as the inode of a dangling symlink.
+rm -f out
+ls -Li d > out 2>/dev/null && fail=1
+compare out subdir_exp || fail=1
+
 Exit $fail
--
1.6.5.rc2.177.ga9dd6