[PATCH] remove: without -f, avoid unnecessary-expense/issues with euidaccess

[Jim Meyering]

Thinking about how one should avoid euidaccess,
I noticed that this corner of remove.c wasn't quite right:
if we call faccessat and it fails, there's no point in trying
with crufty, less-robust interfaces.

While technically this is a correctness issue,
the cases in which it makes a difference are so far-fetched
that it's not worth trying to write the test case.

Here's the fix:

>From 0d48e1d317844ffcadb434a694438e14993a4be9 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sat, 6 Mar 2010 13:16:19 +0100
Subject: [PATCH] remove: without -f, avoid unnecessary-expense/issues with 
euidaccess

* src/remove.c (write_protected_non_symlink): If faccessat fails,
return 1 or -1 directly, rather than falling back on euidaccess*.
---
 src/remove.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/remove.c b/src/remove.c
index b6cfc8e..d0b2dae 100644
--- a/src/remove.c
+++ b/src/remove.c
@@ -171,9 +171,13 @@ write_protected_non_symlink (int fd_cwd,
   {
     /* This implements #1: on decent systems, either faccessat is
        native or /proc/self/fd allows us to skip a chdir.  */
-    if (!openat_needs_fchdir ()
-        && faccessat (fd_cwd, file, W_OK, AT_EACCESS) == 0)
-      return 0;
+    if (!openat_needs_fchdir ())
+      {
+        if (faccessat (fd_cwd, file, W_OK, AT_EACCESS) == 0)
+          return 0;
+
+        return errno == EACCES ? 1 : -1;
+      }

     /* This implements #5: */
     size_t file_name_len = strlen (full_name);
--
1.7.0.1.324.g3bb92