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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 "gdb_string.h"
  24 #include "gdbcore.h"
  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   if (environ == NULL)
  68     return;
  69
  70   for (i = 0; environ[i]; i++) /*EMPTY*/;
  71
  72   if (e->allocated < i)
  73     {
  74       e->allocated = max (i, e->allocated + 10);
  75       e->vector = (char **) xrealloc ((char *)e->vector,
  76                                       (e->allocated + 1) * sizeof (char *));
  77     }
  78
  79   memcpy (e->vector, environ, (i + 1) * sizeof (char *));
  80
  81   while (--i >= 0)
  82     {
  83       register int len = strlen (e->vector[i]);
  84       register char *new = (char *) xmalloc (len + 1);
  85       memcpy (new, e->vector[i], len + 1);
  86       e->vector[i] = new;
  87     }
  88 }
  89
  90 /* Return the vector of environment E.
  91    This is used to get something to pass to execve.  */
  92
  93 char **
  94 environ_vector (e)
  95      struct environ *e;
  96 {
  97   return e->vector;
  98 }
  99 \f
 100 /* Return the value in environment E of variable VAR.  */
 101
 102 char *
 103 get_in_environ (e, var)
 104      const struct environ *e;
 105      const char *var;
 106 {
 107   register int len = strlen (var);
 108   register char **vector = e->vector;
 109   register char *s;
 110
 111   for (; (s = *vector) != NULL; vector++)
 112     if (STREQN (s, var, len) && s[len] == '=')
 113       return &s[len + 1];
 114
 115   return 0;
 116 }
 117
 118 /* Store the value in E of VAR as VALUE.  */
 119
 120 void
 121 set_in_environ (e, var, value)
 122      struct environ *e;
 123      const char *var;
 124      const char *value;
 125 {
 126   register int i;
 127   register int len = strlen (var);
 128   register char **vector = e->vector;
 129   register char *s;
 130
 131   for (i = 0; (s = vector[i]) != NULL; i++)
 132     if (STREQN (s, var, len) && s[len] == '=')
 133       break;
 134
 135   if (s == 0)
 136     {
 137       if (i == e->allocated)
 138         {
 139           e->allocated += 10;
 140           vector = (char **) xrealloc ((char *)vector,
 141                                        (e->allocated + 1) * sizeof (char *));
 142           e->vector = vector;
 143         }
 144       vector[i + 1] = 0;
 145     }
 146   else
 147     free (s);
 148
 149   s = (char *) xmalloc (len + strlen (value) + 2);
 150   strcpy (s, var);
 151   strcat (s, "=");
 152   strcat (s, value);
 153   vector[i] = s;
 154
 155   /* This used to handle setting the PATH and GNUTARGET variables
 156      specially.  The latter has been replaced by "set gnutarget"
 157      (which has worked since GDB 4.11).  The former affects searching
 158      the PATH to find SHELL, and searching the PATH to find the
 159      argument of "symbol-file" or "exec-file".  Maybe we should have
 160      some kind of "set exec-path" for that.  But in any event, having
 161      "set env" affect anything besides the inferior is a bad idea.
 162      What if we want to change the environment we pass to the program
 163      without afecting GDB's behavior?  */
 164
 165   return;
 166 }
 167
 168 /* Remove the setting for variable VAR from environment E.  */
 169
 170 void
 171 unset_in_environ (e, var)
 172      struct environ *e;
 173      char *var;
 174 {
 175   register int len = strlen (var);
 176   register char **vector = e->vector;
 177   register char *s;
 178
 179   for (; (s = *vector) != NULL; vector++)
 180     {
 181       if (STREQN (s, var, len) && s[len] == '=')
 182         {
 183           free (s);
 184           /* Walk through the vector, shuffling args down by one, including
 185              the NULL terminator.  Can't use memcpy() here since the regions
 186              overlap, and memmove() might not be available. */
 187           while ((vector[0] = vector[1]) != NULL)
 188             {
 189               vector++;
 190             }
 191           break;
 192         }
 193     }
 194 }