maint: replace FSF snail-mail addresses with URLs * config/argz.mk, lib/accept4.c, lib/alignof.h, lib/alloca.in.h: * lib/alphasort.c, lib/arcfour.c, lib/arcfour.h, lib/arctwo.c: * lib/arctwo.h, lib/argz.c, lib/arpa_inet.in.h, lib/asnprintf.c: * lib/asprintf.c, lib/assert.in.h, lib/base32.c, lib/base32.h: * lib/base64.c, lib/base64.h, lib/c-ctype.c, lib/c-ctype.h: * lib/c-strcase.h, lib/c-strcasecmp.c, lib/c-strncasecmp.c: * lib/check-version.c, lib/check-version.h, lib/config.charset: * lib/ctype.in.h, lib/des.c, lib/des.h, lib/dup3.c, lib/errno.in.h: * lib/float+.h, lib/fnmatch.c, lib/fnmatch.in.h, lib/fnmatch_loop.c: * lib/fseeko.c, lib/gai_strerror.c, lib/gc-gnulib.c: * lib/gc-libgcrypt.c, lib/gc-pbkdf2-sha1.c, lib/gc.h: * lib/getaddrinfo.c, lib/getdelim.c, lib/getfilecon.c, lib/getline.c: * lib/getlogin_r.c, lib/getpass.c, lib/getpass.h, lib/gettext.h: * lib/gettimeofday.c, lib/glob.in.h, lib/glthread/cond.c: * lib/glthread/cond.h, lib/glthread/lock.c, lib/glthread/lock.h: * lib/glthread/thread.c, lib/glthread/thread.h: * lib/glthread/threadlib.c, lib/glthread/yield.h, lib/hmac-md5.c: * lib/hmac-sha1.c, lib/hmac.h, lib/iconv.c, lib/iconv.in.h: * lib/iconv_close.c, lib/iconv_open.c, lib/inet_ntop.c, lib/isfinite.c: * lib/isinf.c, lib/iswblank.c, lib/langinfo.in.h, lib/link.c: * lib/localcharset.c, lib/localcharset.h, lib/lseek.c, lib/malloc.c: * lib/malloca.c, lib/malloca.h, lib/md2.c, lib/md2.h, lib/md4.c: * lib/md4.h, lib/md5.c, lib/md5.h, lib/memmem.c, lib/mempcpy.c: * lib/memset.c, lib/memxor.c, lib/memxor.h, lib/minmax.h, lib/mktime.c: * lib/msvc-inval.c, lib/msvc-inval.h, lib/msvc-nothrow.c: * lib/msvc-nothrow.h, lib/netdb.in.h, lib/netinet_in.in.h, lib/nproc.c: * lib/nproc.h, lib/obstack_printf.c, lib/pathmax.h, lib/pipe.c: * lib/pipe2.c, lib/poll.c, lib/poll.in.h, lib/printf-args.c: * lib/printf-args.h, lib/printf-parse.c, lib/printf-parse.h: * lib/pselect.c, lib/pthread.in.h, lib/pty-private.h, lib/pty.in.h: * lib/read-file.c, lib/read-file.h, lib/ref-add.sin, lib/ref-del.sin: * lib/regcomp.c, lib/regex.c, lib/regex.h, lib/regex_internal.c: * lib/regex_internal.h, lib/regexec.c, lib/rijndael-alg-fst.c: * lib/rijndael-alg-fst.h, lib/rijndael-api-fst.c: * lib/rijndael-api-fst.h, lib/rint.c, lib/rintf.c, lib/rintl.c: * lib/round.c, lib/roundf.c, lib/roundl.c, lib/scandir.c, lib/select.c: * lib/sha1.c, lib/sha1.h, lib/size_max.h, lib/snprintf.c: * lib/stdalign.in.h, lib/stdarg.in.h, lib/stdbool.in.h: * lib/stddef.in.h, lib/stdint.in.h, lib/stdio.in.h, lib/str-kmp.h: * lib/str-two-way.h, lib/strcasecmp.c, lib/strcasestr.c, lib/strdup.c: * lib/striconv.c, lib/striconv.h, lib/string.in.h, lib/strings.in.h: * lib/strncasecmp.c, lib/strndup.c, lib/strnlen.c, lib/strpbrk.c: * lib/strptime.c, lib/strsep.c, lib/strstr.c, lib/strverscmp.c: * lib/sys_file.in.h, lib/sys_ioctl.in.h, lib/sys_select.in.h: * lib/sys_socket.in.h, lib/sys_stat.in.h, lib/sys_time.in.h: * lib/sys_times.in.h, lib/sys_types.in.h, lib/sys_uio.in.h: * lib/sys_utsname.in.h, lib/sys_wait.in.h, lib/tcgetsid.c: * lib/termios.in.h, lib/time.in.h, lib/time_r.c, lib/timegm.c: * lib/times.c, lib/unictype/3level.h, lib/unictype/3levelbit.h: * lib/unistd.in.h, lib/vasnprintf.c, lib/vasnprintf.h, lib/vasprintf.c: * lib/vsnprintf.c, lib/waitpid.c, lib/wchar.in.h, lib/wctype.in.h: * lib/xsize.h, tests/test-closein.c, tests/test-des.c: * tests/test-fclose.c, tests/test-fgetc.c, tests/test-filevercmp.c: * tests/test-fputc.c, tests/test-fread.c, tests/test-fwrite.c: * tests/test-gc-arcfour.c, tests/test-gc-arctwo.c, tests/test-gc-des.c: * tests/test-gc-hmac-md5.c, tests/test-gc-hmac-sha1.c: * tests/test-gc-md2.c, tests/test-gc-md4.c, tests/test-gc-md5.c: * tests/test-gc-pbkdf2-sha1.c, tests/test-gc-rijndael.c: * tests/test-gc-sha1.c, tests/test-gc.c, tests/test-getdelim.c: * tests/test-getline.c, tests/test-getndelim2.c, tests/test-md2.c: * tests/test-md4.c, tests/test-parse-datetime.c, tests/test-perror.c: * tests/test-perror2.c, tests/test-pipe.c, tests/test-pipe2.c: * tests/test-poll.c, tests/test-quotearg-simple.c: * tests/test-quotearg.c, tests/test-quotearg.h: * tests/test-round-ieee.c, tests/test-round1.c: * tests/test-roundf-ieee.c, tests/test-roundf1.c: * tests/test-roundl-ieee.c, tests/test-roundl.c: * tests/test-safe-alloc.c, tests/test-sigpipe.c: * tests/test-spawn-pipe-child.c, tests/test-spawn-pipe-main.c: * tests/test-strerror.c, tests/test-strerror_r.c: * tests/test-strsignal.c, tests/test-strverscmp.c: * tests/test-xmemdup0.c: Replace FSF snail mail addresses with URLs, as per GNU coding standards. See glibc bug <http://sourceware.org/bugzilla/show_bug.cgi?id=13673>.

/* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2012 Free Software
   Foundation, Inc.

   NOTE: The canonical source of this file is maintained with the GNU C
   Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.

   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 3 of the License, or 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.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <stdlib.h>

#include <stddef.h>

/* Include errno.h *after* sys/types.h to work around header problems
   on AIX 3.2.5.  */
#include <errno.h>
#ifndef __set_errno
# define __set_errno(ev) ((errno) = (ev))
#endif

#include <string.h>
#include <unistd.h>

#if _LIBC
# if HAVE_GNU_LD
#  define environ __environ
# else
extern char **environ;
# endif
#endif

#if _LIBC
/* This lock protects against simultaneous modifications of 'environ'.  */
# include <bits/libc-lock.h>
__libc_lock_define_initialized (static, envlock)
# define LOCK   __libc_lock_lock (envlock)
# define UNLOCK __libc_lock_unlock (envlock)
#else
# define LOCK
# define UNLOCK
#endif

static int
_unsetenv (const char *name)
{
  size_t len;
  char **ep;

  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
    {
      __set_errno (EINVAL);
      return -1;
    }

  len = strlen (name);

  LOCK;

  ep = environ;
  while (*ep != NULL)
    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
      {
        /* Found it.  Remove this pointer by moving later ones back.  */
        char **dp = ep;

        do
          dp[0] = dp[1];
        while (*dp++);
        /* Continue the loop in case NAME appears again.  */
      }
    else
      ++ep;

  UNLOCK;

  return 0;
}


/* Put STRING, which is of the form "NAME=VALUE", in the environment.
   If STRING contains no '=', then remove STRING from the environment.  */
int
putenv (char *string)
{
  const char *const name_end = strchr (string, '=');
  register size_t size;
  register char **ep;

  if (name_end == NULL)
    {
      /* Remove the variable from the environment.  */
      return _unsetenv (string);
    }

  size = 0;
  for (ep = environ; *ep != NULL; ++ep)
    if (!strncmp (*ep, string, name_end - string) &&
        (*ep)[name_end - string] == '=')
      break;
    else
      ++size;

  if (*ep == NULL)
    {
      static char **last_environ = NULL;
      char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
      if (new_environ == NULL)
        return -1;
      (void) memcpy ((void *) new_environ, (void *) environ,
                     size * sizeof (char *));
      new_environ[size] = (char *) string;
      new_environ[size + 1] = NULL;
      free (last_environ);
      last_environ = new_environ;
      environ = new_environ;
    }
  else
    *ep = string;

  return 0;
}