gdb/environ.c

   1 /* environ.c -- library for manipulating environments for GNU.
   2    Copyright (C) 1986, 1989 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 2 of the License, or
   7 (at your option) any later version.
   8
   9 This program 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
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 #define min(a, b) ((a) < (b) ? (a) : (b))
  19 #define max(a, b) ((a) > (b) ? (a) : (b))
  20
  21 #include "defs.h"
  22 #include "environ.h"
  23 #include <string.h>
  24 #include "defs.h" /* For strsave().  */
  25
  26 \f
  27 /* Return a new environment object.  */
  28
  29 struct environ *
  30 make_environ ()
  31 {
  32   register struct environ *e;
  33
  34   e = (struct environ *) xmalloc (sizeof (struct environ));
  35
  36   e->allocated = 10;
  37   e->vector = (char **) xmalloc ((e->allocated + 1) * sizeof (char *));
  38   e->vector[0] = 0;
  39   return e;
  40 }
  41
  42 /* Free an environment and all the strings in it.  */
  43
  44 void
  45 free_environ (e)
  46      register struct environ *e;
  47 {
  48   register char **vector = e->vector;
  49
  50   while (*vector)
  51     free (*vector++);
  52
  53   free (e);
  54 }
  55
  56 /* Copy the environment given to this process into E.
  57    Also copies all the strings in it, so we can be sure
  58    that all strings in these environments are safe to free.  */
  59
  60 void
  61 init_environ (e)
  62      register struct environ *e;
  63 {
  64   extern char **environ;
  65   register int i;
  66
  67   for (i = 0; environ[i]; i++) /*EMPTY*/;
  68
  69   if (e->allocated < i)
  70     {
  71       e->allocated = max (i, e->allocated + 10);
  72       e->vector = (char **) xrealloc ((char *)e->vector,
  73                                       (e->allocated + 1) * sizeof (char *));
  74     }
  75
  76   memcpy (e->vector, environ, (i + 1) * sizeof (char *));
  77
  78   while (--i >= 0)
  79     {
  80       register int len = strlen (e->vector[i]);
  81       register char *new = (char *) xmalloc (len + 1);
  82       memcpy (new, e->vector[i], len + 1);
  83       e->vector[i] = new;
  84     }
  85 }
  86
  87 /* Return the vector of environment E.
  88    This is used to get something to pass to execve.  */
  89
  90 char **
  91 environ_vector (e)
  92      struct environ *e;
  93 {
  94   return e->vector;
  95 }
  96 \f
  97 /* Return the value in environment E of variable VAR.  */
  98
  99 char *
 100 get_in_environ (e, var)
 101      const struct environ *e;
 102      const char *var;
 103 {
 104   register int len = strlen (var);
 105   register char **vector = e->vector;
 106   register char *s;
 107
 108   for (; (s = *vector) != NULL; vector++)
 109     if (STREQN (s, var, len) && s[len] == '=')
 110       return &s[len + 1];
 111
 112   return 0;
 113 }
 114
 115 /* Store the value in E of VAR as VALUE.  */
 116
 117 void
 118 set_in_environ (e, var, value)
 119      struct environ *e;
 120      const char *var;
 121      const char *value;
 122 {
 123   register int i;
 124   register int len = strlen (var);
 125   register char **vector = e->vector;
 126   register char *s;
 127
 128   for (i = 0; (s = vector[i]) != NULL; i++)
 129     if (STREQN (s, var, len) && s[len] == '=')
 130       break;
 131
 132   if (s == 0)
 133     {
 134       if (i == e->allocated)
 135         {
 136           e->allocated += 10;
 137           vector = (char **) xrealloc ((char *)vector,
 138                                        (e->allocated + 1) * sizeof (char *));
 139           e->vector = vector;
 140         }
 141       vector[i + 1] = 0;
 142     }
 143   else
 144     free (s);
 145
 146   s = (char *) xmalloc (len + strlen (value) + 2);
 147   strcpy (s, var);
 148   strcat (s, "=");
 149   strcat (s, value);
 150   vector[i] = s;
 151
 152   /* Certain variables get exported back to the parent (e.g. our)
 153      environment, too.  FIXME: this is a hideous hack and should not be
 154      allowed to live.  What if we want to change the environment we pass to
 155      the program without affecting GDB's behavior?  */
 156   if (STREQ(var, "PATH")                /* Object file location */
 157       || STREQ (var, "G960BASE")                /* Intel 960 downloads */
 158       || STREQ (var, "G960BIN")                 /* Intel 960 downloads */
 159       )
 160     {
 161       putenv (strsave (s));
 162     }
 163
 164   /* This is a compatibility hack, since GDB 4.10 and older didn't have
 165      `set gnutarget'.  Eventually it should go away, so that (for example)
 166      you can debug objdump's handling of GNUTARGET without affecting GDB's
 167      behavior.  */
 168   if (STREQ (var, "GNUTARGET"))
 169     {
 170       set_gnutarget (value);
 171     }
 172   return;
 173 }
 174
 175 /* Remove the setting for variable VAR from environment E.  */
 176
 177 void
 178 unset_in_environ (e, var)
 179      struct environ *e;
 180      char *var;
 181 {
 182   register int len = strlen (var);
 183   register char **vector = e->vector;
 184   register char *s;
 185
 186   for (; (s = *vector) != NULL; vector++)
 187     {
 188       if (STREQN (s, var, len) && s[len] == '=')
 189         {
 190           free (s);
 191           /* Walk through the vector, shuffling args down by one, including
 192              the NULL terminator.  Can't use memcpy() here since the regions
 193              overlap, and memmove() might not be available. */
 194           while ((vector[0] = vector[1]) != NULL)
 195             {
 196               vector++;
 197             }
 198           break;
 199         }
 200     }
 201 }