X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fcareadlinkat.c;h=cd4aa846dcaac99ae3016a059bc33df78f2505ef;hb=150ce1bef700d6a3e56861c3a316da64be93d880;hp=7a7806d121c60cbd731ebe9842660f5f6fa741db;hpb=cb4ce86374195eccbc3591f74a0c7b8168273667;p=gnulib.git

diff --git a/lib/careadlinkat.c b/lib/careadlinkat.c
index 7a7806d12..cd4aa846d 100644
--- a/lib/careadlinkat.c
+++ b/lib/careadlinkat.c
@@ -1,6 +1,6 @@
 /* Read symbolic links into a buffer without size limitation, relative to fd.
 
-   Copyright (C) 2001, 2003-2004, 2007, 2009-2011 Free Software Foundation,
+   Copyright (C) 2001, 2003-2004, 2007, 2009-2012 Free Software Foundation,
    Inc.
 
    This program is free software: you can redistribute it and/or modify
@@ -22,10 +22,9 @@
 
 #include "careadlinkat.h"
 
-#include "allocator.h"
-
 #include <errno.h>
 #include <limits.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -38,18 +37,21 @@
 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
 #endif
 
-#if ! HAVE_READLINKAT
-/* Ignore FD.  Get the symbolic link value of FILENAME and put it into
-   BUFFER, with size BUFFER_SIZE.  This function acts like readlink
-   but has readlinkat's signature.  */
+#include "allocator.h"
+
+/* Get the symbolic link value of FILENAME and put it into BUFFER, with
+   size BUFFER_SIZE.  This function acts like readlink  but has
+   readlinkat's signature.  */
 ssize_t
 careadlinkatcwd (int fd, char const *filename, char *buffer,
                  size_t buffer_size)
 {
-  (void) fd;
+  /* FD must be AT_FDCWD here, otherwise the caller is using this
+     function in contexts for which it was not meant for.  */
+  if (fd != AT_FDCWD)
+    abort ();
   return readlink (filename, buffer, buffer_size);
 }
-#endif
 
 /* Assuming the current directory is FD, get the symbolic link value
    of FILENAME as a null-terminated string and put it into a buffer.
@@ -65,7 +67,10 @@ careadlinkatcwd (int fd, char const *filename, char *buffer,
    the returned value if it is nonnull and is not BUFFER.  A null
    ALLOC stands for the standard allocator.
 
-   The PREADLINKAT function specifies how to read links.
+   The PREADLINKAT function specifies how to read links.  It operates
+   like POSIX readlinkat()
+   <http://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html>
+   but can assume that its first argument is the same as FD.
 
    If successful, return the buffer address; otherwise return NULL and
    set errno.  */
@@ -128,6 +133,7 @@ careadlinkat (int fd, char const *filename,
           if (buf == stack_buf)
             {
               char *b = (char *) alloc->allocate (link_size);
+              buf_size = link_size;
               if (! b)
                 break;
               memcpy (b, buf, link_size);
@@ -151,6 +157,11 @@ careadlinkat (int fd, char const *filename,
         buf_size *= 2;
       else if (buf_size < buf_size_max)
         buf_size = buf_size_max;
+      else if (buf_size_max < SIZE_MAX)
+        {
+          errno = ENAMETOOLONG;
+          return NULL;
+        }
       else
         break;
       buf = (char *) alloc->allocate (buf_size);
@@ -158,7 +169,7 @@ careadlinkat (int fd, char const *filename,
   while (buf);
 
   if (alloc->die)
-    alloc->die ();
+    alloc->die (buf_size);
   errno = ENOMEM;
   return NULL;
 }