doc: use ASCII in .texi files where UTF-8 isn't needed

[gnulib.git] / lib / areadlink.c

diff --git a/lib/areadlink.c b/lib/areadlink.c
index 1b01d6f..b4b856c 100644 (file)
--- a/lib/areadlink.c
+++ b/lib/areadlink.c
@@ -1,12 +1,12 @@
 /* areadlink.c -- readlink wrapper to return the link name in malloc'd storage
    Unlike xreadlink and xreadlink_with_size, don't ever call exit.
 
-   Copyright (C) 2001, 2003-2007 Free Software Foundation, Inc.
+   Copyright (C) 2001, 2003-2007, 2009-2014 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -14,9 +14,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; see the file COPYING.
-   If not, write to the Free Software Foundation,
-   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Written by Jim Meyering <jim@meyering.net>
    and Bruno Haible <bruno@clisp.org>.  */
@@ -26,97 +24,33 @@
 /* Specification.  */
 #include "areadlink.h"
 
-#include <string.h>
-#include <errno.h>
-#include <limits.h>
-#include <sys/types.h>
+#include "careadlinkat.h"
+
 #include <stdlib.h>
 #include <unistd.h>
 
-#ifndef SIZE_MAX
-# define SIZE_MAX ((size_t) -1)
-#endif
-#ifndef SSIZE_MAX
-# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
-#endif
+/* 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.  */
+static ssize_t
+careadlinkatcwd (int fd, char const *filename, char *buffer,
+                 size_t buffer_size)
+{
+  /* FD must be AT_FDCWD here, otherwise the caller is using this
+     function in contexts it was not meant for.  */
+  if (fd != AT_FDCWD)
+    abort ();
+  return readlink (filename, buffer, buffer_size);
+}
 
 /* Call readlink to get the symbolic link value of FILENAME.
    Return a pointer to that NUL-terminated string in malloc'd storage.
    If readlink fails, return NULL and set errno.
-   If realloc fails, or if the link value is longer than SIZE_MAX :-),
+   If allocation fails, or if the link value is longer than SIZE_MAX :-),
    return NULL and set errno to ENOMEM.  */
 
 char *
 areadlink (char const *filename)
 {
-  /* The initial buffer size for the link value.  A power of 2
-     detects arithmetic overflow earlier, but is not required.  */
-#define INITIAL_BUF_SIZE 1024
-
-  /* Allocate the initial buffer on the stack.  This way, in the common
-     case of a symlink of small size, we get away with a single small malloc()
-     instead of a big malloc() followed by a shrinking realloc().  */
-  char initial_buf[INITIAL_BUF_SIZE];
-
-  char *buffer = initial_buf;
-  size_t buf_size = sizeof (initial_buf);
-
-  while (1)
-    {
-      /* Attempt to read the link into the current buffer.  */
-      ssize_t link_length = readlink (filename, buffer, buf_size);
-
-      /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
-        with errno == ERANGE if the buffer is too small.  */
-      if (link_length < 0 && errno != ERANGE)
-       {
-         if (buffer != initial_buf)
-           {
-             int saved_errno = errno;
-             free (buffer);
-             errno = saved_errno;
-           }
-         return NULL;
-       }
-
-      if ((size_t) link_length < buf_size)
-       {
-         buffer[link_length++] = '\0';
-
-         /* Return it in a chunk of memory as small as possible.  */
-         if (buffer == initial_buf)
-           {
-             buffer = (char *) malloc (link_length);
-             if (buffer == NULL)
-               /* errno is ENOMEM.  */
-               return NULL;
-             memcpy (buffer, initial_buf, link_length);
-           }
-         else
-           {
-             /* Shrink buffer before returning it.  */
-             if ((size_t) link_length < buf_size)
-               {
-                 char *smaller_buffer = (char *) realloc (buffer, link_length);
-
-                 if (smaller_buffer != NULL)
-                   buffer = smaller_buffer;
-               }
-           }
-         return buffer;
-       }
-
-      if (buffer != initial_buf)
-       free (buffer);
-      buf_size *= 2;
-      if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
-       {
-         errno = ENOMEM;
-         return NULL;
-       }
-      buffer = (char *) malloc (buf_size);
-      if (buffer == NULL)
-       /* errno is ENOMEM.  */
-       return NULL;
-    }
+  return careadlinkat (AT_FDCWD, filename, NULL, 0, NULL, careadlinkatcwd);
 }