libiberty/putenv.c

   1 /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
   2    This file based on putenv.c in the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  17    Boston, MA 02110-1301, USA.  */
  18
  19 /*
  20
  21 @deftypefn Supplemental int putenv (const char *@var{string})
  22
  23 Uses @code{setenv} or @code{unsetenv} to put @var{string} into
  24 the environment or remove it.  If @var{string} is of the form
  25 @samp{name=value} the string is added; if no @samp{=} is present the
  26 name is unset/removed.
  27
  28 @end deftypefn
  29
  30 */
  31
  32 #if defined (_AIX) && !defined (__GNUC__)
  33  #pragma alloca
  34 #endif
  35
  36 #if HAVE_CONFIG_H
  37 # include <config.h>
  38 #endif
  39
  40 #include "ansidecl.h"
  41
  42 #define putenv libiberty_putenv
  43
  44 #if HAVE_STDLIB_H
  45 # include <stdlib.h>
  46 #endif
  47 #if HAVE_STRING_H
  48 # include <string.h>
  49 #endif
  50
  51 #ifdef HAVE_ALLOCA_H
  52 # include <alloca.h>
  53 #else
  54 # ifndef alloca
  55 #  ifdef __GNUC__
  56 #   define alloca __builtin_alloca
  57 #  else
  58 extern char *alloca ();
  59 #  endif /* __GNUC__ */
  60 # endif /* alloca */
  61 #endif /* HAVE_ALLOCA_H */
  62
  63 #undef putenv
  64
  65 /* Below this point, it's verbatim code from the glibc-2.0 implementation */
  66
  67
  68 /* Put STRING, which is of the form "NAME=VALUE", in the environment.  */
  69 int
  70 putenv (const char *string)
  71 {
  72   const char *const name_end = strchr (string, '=');
  73
  74   if (name_end)
  75     {
  76       char *name = (char *) alloca (name_end - string + 1);
  77       memcpy (name, string, name_end - string);
  78       name[name_end - string] = '\0';
  79       return setenv (name, name_end + 1, 1);
  80     }
  81
  82   unsetenv (string);
  83   return 0;
  84 }