gdb/environ.c

   1 /* environ.c -- library for manipulating environments for GNU.
   2
   3    Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 2000, 2005
   4    2003, 2007 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #define min(a, b) ((a) < (b) ? (a) : (b))
  20 #define max(a, b) ((a) > (b) ? (a) : (b))
  21
  22 #include "defs.h"
  23 #include "environ.h"
  24 #include "gdb_string.h"
  25 \f
  26
  27 /* Return a new environment object.  */
  28
  29 struct gdb_environ *
  30 make_environ (void)
  31 {
  32   struct gdb_environ *e;
  33
  34   e = (struct gdb_environ *) xmalloc (sizeof (struct gdb_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 (struct gdb_environ *e)
  46 {
  47   char **vector = e->vector;
  48
  49   while (*vector)
  50     xfree (*vector++);
  51
  52   xfree (e);
  53 }
  54
  55 /* Copy the environment given to this process into E.
  56    Also copies all the strings in it, so we can be sure
  57    that all strings in these environments are safe to free.  */
  58
  59 void
  60 init_environ (struct gdb_environ *e)
  61 {
  62   extern char **environ;
  63   int i;
  64
  65   if (environ == NULL)
  66     return;
  67
  68   for (i = 0; environ[i]; i++) /*EMPTY */ ;
  69
  70   if (e->allocated < i)
  71     {
  72       e->allocated = max (i, e->allocated + 10);
  73       e->vector = (char **) xrealloc ((char *) e->vector,
  74                                       (e->allocated + 1) * sizeof (char *));
  75     }
  76
  77   memcpy (e->vector, environ, (i + 1) * sizeof (char *));
  78
  79   while (--i >= 0)
  80     {
  81       int len = strlen (e->vector[i]);
  82       char *new = (char *) xmalloc (len + 1);
  83       memcpy (new, e->vector[i], len + 1);
  84       e->vector[i] = new;
  85     }
  86 }
  87
  88 /* Return the vector of environment E.
  89    This is used to get something to pass to execve.  */
  90
  91 char **
  92 environ_vector (struct gdb_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 (const struct gdb_environ *e, const char *var)
 101 {
 102   int len = strlen (var);
 103   char **vector = e->vector;
 104   char *s;
 105
 106   for (; (s = *vector) != NULL; vector++)
 107     if (strncmp (s, var, len) == 0 && s[len] == '=')
 108       return &s[len + 1];
 109
 110   return 0;
 111 }
 112
 113 /* Store the value in E of VAR as VALUE.  */
 114
 115 void
 116 set_in_environ (struct gdb_environ *e, const char *var, const char *value)
 117 {
 118   int i;
 119   int len = strlen (var);
 120   char **vector = e->vector;
 121   char *s;
 122
 123   for (i = 0; (s = vector[i]) != NULL; i++)
 124     if (strncmp (s, var, len) == 0 && s[len] == '=')
 125       break;
 126
 127   if (s == 0)
 128     {
 129       if (i == e->allocated)
 130         {
 131           e->allocated += 10;
 132           vector = (char **) xrealloc ((char *) vector,
 133                                        (e->allocated + 1) * sizeof (char *));
 134           e->vector = vector;
 135         }
 136       vector[i + 1] = 0;
 137     }
 138   else
 139     xfree (s);
 140
 141   s = (char *) xmalloc (len + strlen (value) + 2);
 142   strcpy (s, var);
 143   strcat (s, "=");
 144   strcat (s, value);
 145   vector[i] = s;
 146
 147   /* This used to handle setting the PATH and GNUTARGET variables
 148      specially.  The latter has been replaced by "set gnutarget"
 149      (which has worked since GDB 4.11).  The former affects searching
 150      the PATH to find SHELL, and searching the PATH to find the
 151      argument of "symbol-file" or "exec-file".  Maybe we should have
 152      some kind of "set exec-path" for that.  But in any event, having
 153      "set env" affect anything besides the inferior is a bad idea.
 154      What if we want to change the environment we pass to the program
 155      without afecting GDB's behavior?  */
 156
 157   return;
 158 }
 159
 160 /* Remove the setting for variable VAR from environment E.  */
 161
 162 void
 163 unset_in_environ (struct gdb_environ *e, char *var)
 164 {
 165   int len = strlen (var);
 166   char **vector = e->vector;
 167   char *s;
 168
 169   for (; (s = *vector) != NULL; vector++)
 170     {
 171       if (strncmp (s, var, len) == 0 && s[len] == '=')
 172         {
 173           xfree (s);
 174           /* Walk through the vector, shuffling args down by one, including
 175              the NULL terminator.  Can't use memcpy() here since the regions
 176              overlap, and memmove() might not be available. */
 177           while ((vector[0] = vector[1]) != NULL)
 178             {
 179               vector++;
 180             }
 181           break;
 182         }
 183     }
 184 }