kc3-lang/gnulib/lib/unsetenv.c

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• Hash : 281b825e
  Author :
  Date : 2018-01-01T00:57:25
  

  maint: Run 'make update-copyright'
  

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• lib/unsetenv.c

• /* Copyright (C) 1992, 1995-2002, 2005-2018 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     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
     (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.  If not, see <https://www.gnu.org/licenses/>.  */
  
  /* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
     optimizes away the name == NULL test below.  */
  #define _GL_ARG_NONNULL(params)
  
  #include <config.h>
  
  /* Specification.  */
  #include <stdlib.h>
  
  #include <errno.h>
  #if !_LIBC
  # define __set_errno(ev) ((errno) = (ev))
  #endif
  
  #include <string.h>
  #include <unistd.h>
  
  #if !_LIBC
  # define __environ      environ
  #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
  
  /* In the GNU C library we must keep the namespace clean.  */
  #ifdef _LIBC
  # define unsetenv __unsetenv
  #endif
  
  #if _LIBC || !HAVE_UNSETENV
  
  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;
  }
  
  #ifdef _LIBC
  # undef unsetenv
  weak_alias (__unsetenv, unsetenv)
  #endif
  
  #else /* HAVE_UNSETENV */
  
  # undef unsetenv
  # if !HAVE_DECL_UNSETENV
  #  if VOID_UNSETENV
  extern void unsetenv (const char *);
  #  else
  extern int unsetenv (const char *);
  #  endif
  # endif
  
  /* Call the underlying unsetenv, in case there is hidden bookkeeping
     that needs updating beyond just modifying environ.  */
  int
  rpl_unsetenv (const char *name)
  {
    int result = 0;
    if (!name || !*name || strchr (name, '='))
      {
        errno = EINVAL;
        return -1;
      }
    while (getenv (name))
  # if !VOID_UNSETENV
      result =
  # endif
        unsetenv (name);
    return result;
  }
  
  #endif /* HAVE_UNSETENV */
  

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