xreadlink.c

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Hash : 359c0a71
Author :
Date : 2005-06-02T20:41:04

Sync from coreutils.
Use "file name" when talking about file names, instead of "filename"
or "path", as per the GNU coding standards.

* MODULES.html.sh: mkdir-p renamed from makepath.
filenamecat renamed from path-concat.
* modules/filenamecat: Renamed from modules/path-concat.
(Files): filenamecat.h and filenamecat.c renamed from
path-concat.h and path-concat.c.
(configure.ac): gl_FILE_NAME_CONCAT, not gl_PATH_CONCAT.
(Include): filenamecat.h, not path-concat.h.
* modules/mkdir-p: Renamed from modules/makepath.
(Files): mkdir-p.h and mkdir-p.c renamed from makepath.h and makepath.c.
(configure.ac): gl_MKDIR_PARENTS, not gl_MAKEPATH.
(Include): mkdir-p.h, not makepath.h.
* lib/mkdir-p.c: Renamed from makepath.c.
(make_dir_parents): Renamed from make_path.  All callers changed.
* lib/mkdir-p.h: Likewise.  All includers changed.
* lib/filenamecat.c: Renamed from path-concat.c.
(file_name_concat): Renamed from path_concat.  All callers changed.
[TEST_FILE_NAME_CONCAT]: Renamed from TEST_PATH_CONCAT.
* lib/filenamecat.h: Likewise.  All includers changed.
* lib/acl.c: Don't use "path" or "filename" to mean "file name"
in comments or local variable names.
* lib/basename.c: Likewise.
* lib/canonicalize.c, canonicalize.h: Likewise.
* lib/dirname.c, dirname.h: Likewise.
* lib/euidaccess.c: Likewise.
* lib/exclude.c: Likewise
* lib/fnmatch_.h, fnmatch_loop.c: Likewise.
* lib/fsusage.c, fsuage.h: Likewise.
* lib/fts.c, fts_.h: Likewise.
* lib/getcwd.c: Likewise.
* lib/getloadavg.c: Likewise.
* lib/mkstemp.c: Likewise.
* lib/mountlist.c, mountlist.h: Likewise.
* lib/openat.c, openat.h: Likewise.
* lib/readlink-stub.c: Likewise.
* lib/readutmp.c, readutmp.h: Likewise.
* lib/rename.c: Likewise.
* lib/rmdir.c: Likewise.
* lib/same.c: Likewise.
* lib/savedir.c: Likewise.
* lib/stripslash.c: Likewise.
* lib/tempname.c: Likewise.
* lib/xreadlink.c: Likewise.
* lib/exclude.c (excluded_file_name): Renamed from excluded_filename.
All uses changed.
* lib/exclude.h: Likewise.
* m4/mkdir-p.m4: Renamed from makepath.m4.
(gl_MKDIR_PARENTS): Renamed from gl_MAKEPATH.  All uses changed.
Rename files from makepath.c to mkdir-p.c, and from
makepath.h to mkdir-p.h.
* m4/filenamecat.m4: Renamed from path-concat.m4.
(gl_FILE_NAME_CONCAT): Renamed from gl_PATH_CONCAT.  All uses changed.
Rename files from path-concat.c to filenamecat.c,
and from path-concat.h to filenamecat.h.
* m4/getcwd-path-max.m4: Don't use "path" or "filename" to mean
"file name" in local variables or comments.
* rename.m4: Likewise.

* lib/euidaccess.c (getuid, getgid, getuid, getegid)
[!defined _POSIX_VERSION]: Remove decls; not needed these days.
* lib/idcache.c (getpwuid, getpwnam, getgrgid, getgrnam)
[!defined _POSIX_VERSION]: Remove decls; not needed these days.
* lib/pathmax.h: Include <limits.h> unconditionally, since other
files have been getting away with it for years (MORE/BSD 4.3
is extinct now).
* lib/userspec.c (getpwnam, getgrnam, getgrgid)
[!defined _POSIX_VERSION]: Remove decls; not needed these days.

* lib/pathmax.h (_POSIX_PATH_MAX) [!defined _POSIX_PATH_MAX]:
Define to 256, not 255, as per modern POSIX.

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lib/xreadlink.c

/* xreadlink.c -- readlink wrapper to return the link name in malloc'd storage

   Copyright (C) 2001, 2003, 2004, 2005 Free Software Foundation, Inc.

   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.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   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.  */

/* Written by Jim Meyering <jim@meyering.net>  */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include "xreadlink.h"

#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <stdlib.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif

#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif
#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif

#define MAXSIZE (SIZE_MAX < SSIZE_MAX ? SIZE_MAX : SSIZE_MAX)

#include "xalloc.h"

/* Call readlink to get the symbolic link value of FILE.
   SIZE is a hint as to how long the link is expected to be;
   typically it is taken from st_size.  It need not be correct.
   Return a pointer to that NUL-terminated string in malloc'd storage.
   If readlink fails, return NULL (caller may use errno to diagnose).
   If malloc fails, or if the link value is longer than SSIZE_MAX :-),
   give a diagnostic and exit.  */

char *
xreadlink (char const *file, size_t size)
{
  /* The initial buffer size for the link value.  A power of 2
     detects arithmetic overflow earlier, but is not required.  */
  size_t buf_size = size < MAXSIZE ? size + 1 : MAXSIZE;

  while (1)
    {
      char *buffer = xmalloc (buf_size);
      ssize_t r = readlink (file, buffer, buf_size);
      size_t link_length = r;

      /* 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 (r < 0 && errno != ERANGE)
	{
	  int saved_errno = errno;
	  free (buffer);
	  errno = saved_errno;
	  return NULL;
	}

      if (link_length < buf_size)
	{
	  buffer[link_length] = 0;
	  return buffer;
	}

      free (buffer);
      if (buf_size <= MAXSIZE / 2)
	buf_size *= 2;
      else if (buf_size < MAXSIZE)
	buf_size = MAXSIZE;
      else
	xalloc_die ();
    }
}

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kc3-lang/gnulib/lib/xreadlink.c

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lib/xreadlink.c