gdb/environ.c

   1 /* environ.c -- library for manipulating environments for GNU.
   2
   3    Copyright (C) 1986-2013 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  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 \f
  25
  26 /* Return a new environment object.  */
  27
  28 struct gdb_environ *
  29 make_environ (void)
  30 {
  31   struct gdb_environ *e;
  32
  33   e = (struct gdb_environ *) xmalloc (sizeof (struct gdb_environ));
  34
  35   e->allocated = 10;
  36   e->vector = (char **) xmalloc ((e->allocated + 1) * sizeof (char *));
  37   e->vector[0] = 0;
  38   return e;
  39 }
  40
  41 /* Free an environment and all the strings in it.  */
  42
  43 void
  44 free_environ (struct gdb_environ *e)
  45 {
  46   char **vector = e->vector;
  47
  48   while (*vector)
  49     xfree (*vector++);
  50
  51   xfree (e->vector);
  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
  84       memcpy (new, e->vector[i], len + 1);
  85       e->vector[i] = new;
  86     }
  87 }
  88
  89 /* Return the vector of environment E.
  90    This is used to get something to pass to execve.  */
  91
  92 char **
  93 environ_vector (struct gdb_environ *e)
  94 {
  95   return e->vector;
  96 }
  97 \f
  98 /* Return the value in environment E of variable VAR.  */
  99
 100 char *
 101 get_in_environ (const struct gdb_environ *e, const char *var)
 102 {
 103   int len = strlen (var);
 104   char **vector = e->vector;
 105   char *s;
 106
 107   for (; (s = *vector) != NULL; vector++)
 108     if (strncmp (s, var, len) == 0 && s[len] == '=')
 109       return &s[len + 1];
 110
 111   return 0;
 112 }
 113
 114 /* Store the value in E of VAR as VALUE.  */
 115
 116 void
 117 set_in_environ (struct gdb_environ *e, const char *var, const char *value)
 118 {
 119   int i;
 120   int len = strlen (var);
 121   char **vector = e->vector;
 122   char *s;
 123
 124   for (i = 0; (s = vector[i]) != NULL; i++)
 125     if (strncmp (s, var, len) == 0 && s[len] == '=')
 126       break;
 127
 128   if (s == 0)
 129     {
 130       if (i == e->allocated)
 131         {
 132           e->allocated += 10;
 133           vector = (char **) xrealloc ((char *) vector,
 134                                        (e->allocated + 1) * sizeof (char *));
 135           e->vector = vector;
 136         }
 137       vector[i + 1] = 0;
 138     }
 139   else
 140     xfree (s);
 141
 142   s = (char *) xmalloc (len + strlen (value) + 2);
 143   strcpy (s, var);
 144   strcat (s, "=");
 145   strcat (s, value);
 146   vector[i] = s;
 147
 148   /* This used to handle setting the PATH and GNUTARGET variables
 149      specially.  The latter has been replaced by "set gnutarget"
 150      (which has worked since GDB 4.11).  The former affects searching
 151      the PATH to find SHELL, and searching the PATH to find the
 152      argument of "symbol-file" or "exec-file".  Maybe we should have
 153      some kind of "set exec-path" for that.  But in any event, having
 154      "set env" affect anything besides the inferior is a bad idea.
 155      What if we want to change the environment we pass to the program
 156      without afecting GDB's behavior?  */
 157
 158   return;
 159 }
 160
 161 /* Remove the setting for variable VAR from environment E.  */
 162
 163 void
 164 unset_in_environ (struct gdb_environ *e, char *var)
 165 {
 166   int len = strlen (var);
 167   char **vector = e->vector;
 168   char *s;
 169
 170   for (; (s = *vector) != NULL; vector++)
 171     {
 172       if (strncmp (s, var, len) == 0 && s[len] == '=')
 173         {
 174           xfree (s);
 175           /* Walk through the vector, shuffling args down by one, including
 176              the NULL terminator.  Can't use memcpy() here since the regions
 177              overlap, and memmove() might not be available.  */
 178           while ((vector[0] = vector[1]) != NULL)
 179             {
 180               vector++;
 181             }
 182           break;
 183         }
 184     }
 185 }