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 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 2 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, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19    Boston, MA 02110-1301, USA.  */
  20
  21 #define min(a, b) ((a) < (b) ? (a) : (b))
  22 #define max(a, b) ((a) > (b) ? (a) : (b))
  23
  24 #include "defs.h"
  25 #include "environ.h"
  26 #include "gdb_string.h"
  27 \f
  28
  29 /* Return a new environment object.  */
  30
  31 struct gdb_environ *
  32 make_environ (void)
  33 {
  34   struct gdb_environ *e;
  35
  36   e = (struct gdb_environ *) xmalloc (sizeof (struct gdb_environ));
  37
  38   e->allocated = 10;
  39   e->vector = (char **) xmalloc ((e->allocated + 1) * sizeof (char *));
  40   e->vector[0] = 0;
  41   return e;
  42 }
  43
  44 /* Free an environment and all the strings in it.  */
  45
  46 void
  47 free_environ (struct gdb_environ *e)
  48 {
  49   char **vector = e->vector;
  50
  51   while (*vector)
  52     xfree (*vector++);
  53
  54   xfree (e);
  55 }
  56
  57 /* Copy the environment given to this process into E.
  58    Also copies all the strings in it, so we can be sure
  59    that all strings in these environments are safe to free.  */
  60
  61 void
  62 init_environ (struct gdb_environ *e)
  63 {
  64   extern char **environ;
  65   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       int len = strlen (e->vector[i]);
  84       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 (struct gdb_environ *e)
  95 {
  96   return e->vector;
  97 }
  98 \f
  99 /* Return the value in environment E of variable VAR.  */
 100
 101 char *
 102 get_in_environ (const struct gdb_environ *e, const char *var)
 103 {
 104   int len = strlen (var);
 105   char **vector = e->vector;
 106   char *s;
 107
 108   for (; (s = *vector) != NULL; vector++)
 109     if (strncmp (s, var, len) == 0 && 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 (struct gdb_environ *e, const char *var, const char *value)
 119 {
 120   int i;
 121   int len = strlen (var);
 122   char **vector = e->vector;
 123   char *s;
 124
 125   for (i = 0; (s = vector[i]) != NULL; i++)
 126     if (strncmp (s, var, len) == 0 && s[len] == '=')
 127       break;
 128
 129   if (s == 0)
 130     {
 131       if (i == e->allocated)
 132         {
 133           e->allocated += 10;
 134           vector = (char **) xrealloc ((char *) vector,
 135                                        (e->allocated + 1) * sizeof (char *));
 136           e->vector = vector;
 137         }
 138       vector[i + 1] = 0;
 139     }
 140   else
 141     xfree (s);
 142
 143   s = (char *) xmalloc (len + strlen (value) + 2);
 144   strcpy (s, var);
 145   strcat (s, "=");
 146   strcat (s, value);
 147   vector[i] = s;
 148
 149   /* This used to handle setting the PATH and GNUTARGET variables
 150      specially.  The latter has been replaced by "set gnutarget"
 151      (which has worked since GDB 4.11).  The former affects searching
 152      the PATH to find SHELL, and searching the PATH to find the
 153      argument of "symbol-file" or "exec-file".  Maybe we should have
 154      some kind of "set exec-path" for that.  But in any event, having
 155      "set env" affect anything besides the inferior is a bad idea.
 156      What if we want to change the environment we pass to the program
 157      without afecting GDB's behavior?  */
 158
 159   return;
 160 }
 161
 162 /* Remove the setting for variable VAR from environment E.  */
 163
 164 void
 165 unset_in_environ (struct gdb_environ *e, char *var)
 166 {
 167   int len = strlen (var);
 168   char **vector = e->vector;
 169   char *s;
 170
 171   for (; (s = *vector) != NULL; vector++)
 172     {
 173       if (strncmp (s, var, len) == 0 && s[len] == '=')
 174         {
 175           xfree (s);
 176           /* Walk through the vector, shuffling args down by one, including
 177              the NULL terminator.  Can't use memcpy() here since the regions
 178              overlap, and memmove() might not be available. */
 179           while ((vector[0] = vector[1]) != NULL)
 180             {
 181               vector++;
 182             }
 183           break;
 184         }
 185     }
 186 }