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,
  17    Boston, MA 02111-1307, USA.  */
  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 #include "gdbcore.h"
  26 \f
  27
  28 /* Return a new environment object.  */
  29
  30 struct environ *
  31 make_environ ()
  32 {
  33   register struct environ *e;
  34
  35   e = (struct environ *) xmalloc (sizeof (struct environ));
  36
  37   e->allocated = 10;
  38   e->vector = (char **) xmalloc ((e->allocated + 1) * sizeof (char *));
  39   e->vector[0] = 0;
  40   return e;
  41 }
  42
  43 /* Free an environment and all the strings in it.  */
  44
  45 void
  46 free_environ (e)
  47      register struct environ *e;
  48 {
  49   register char **vector = e->vector;
  50
  51   while (*vector)
  52     free (*vector++);
  53
  54   free (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 (e)
  63      register struct environ *e;
  64 {
  65   extern char **environ;
  66   register int i;
  67
  68   if (environ == NULL)
  69     return;
  70
  71   for (i = 0; environ[i]; i++) /*EMPTY */ ;
  72
  73   if (e->allocated < i)
  74     {
  75       e->allocated = max (i, e->allocated + 10);
  76       e->vector = (char **) xrealloc ((char *) e->vector,
  77                                       (e->allocated + 1) * sizeof (char *));
  78     }
  79
  80   memcpy (e->vector, environ, (i + 1) * sizeof (char *));
  81
  82   while (--i >= 0)
  83     {
  84       register int len = strlen (e->vector[i]);
  85       register char *new = (char *) xmalloc (len + 1);
  86       memcpy (new, e->vector[i], len + 1);
  87       e->vector[i] = new;
  88     }
  89 }
  90
  91 /* Return the vector of environment E.
  92    This is used to get something to pass to execve.  */
  93
  94 char **
  95 environ_vector (e)
  96      struct environ *e;
  97 {
  98   return e->vector;
  99 }
 100 \f
 101 /* Return the value in environment E of variable VAR.  */
 102
 103 char *
 104 get_in_environ (e, var)
 105      const struct environ *e;
 106      const char *var;
 107 {
 108   register int len = strlen (var);
 109   register char **vector = e->vector;
 110   register char *s;
 111
 112   for (; (s = *vector) != NULL; vector++)
 113     if (STREQN (s, var, len) && s[len] == '=')
 114       return &s[len + 1];
 115
 116   return 0;
 117 }
 118
 119 /* Store the value in E of VAR as VALUE.  */
 120
 121 void
 122 set_in_environ (e, var, value)
 123      struct environ *e;
 124      const char *var;
 125      const char *value;
 126 {
 127   register int i;
 128   register int len = strlen (var);
 129   register char **vector = e->vector;
 130   register char *s;
 131
 132   for (i = 0; (s = vector[i]) != NULL; i++)
 133     if (STREQN (s, var, len) && s[len] == '=')
 134       break;
 135
 136   if (s == 0)
 137     {
 138       if (i == e->allocated)
 139         {
 140           e->allocated += 10;
 141           vector = (char **) xrealloc ((char *) vector,
 142                                        (e->allocated + 1) * sizeof (char *));
 143           e->vector = vector;
 144         }
 145       vector[i + 1] = 0;
 146     }
 147   else
 148     free (s);
 149
 150   s = (char *) xmalloc (len + strlen (value) + 2);
 151   strcpy (s, var);
 152   strcat (s, "=");
 153   strcat (s, value);
 154   vector[i] = s;
 155
 156   /* This used to handle setting the PATH and GNUTARGET variables
 157      specially.  The latter has been replaced by "set gnutarget"
 158      (which has worked since GDB 4.11).  The former affects searching
 159      the PATH to find SHELL, and searching the PATH to find the
 160      argument of "symbol-file" or "exec-file".  Maybe we should have
 161      some kind of "set exec-path" for that.  But in any event, having
 162      "set env" affect anything besides the inferior is a bad idea.
 163      What if we want to change the environment we pass to the program
 164      without afecting GDB's behavior?  */
 165
 166   return;
 167 }
 168
 169 /* Remove the setting for variable VAR from environment E.  */
 170
 171 void
 172 unset_in_environ (e, var)
 173      struct environ *e;
 174      char *var;
 175 {
 176   register int len = strlen (var);
 177   register char **vector = e->vector;
 178   register char *s;
 179
 180   for (; (s = *vector) != NULL; vector++)
 181     {
 182       if (STREQN (s, var, len) && s[len] == '=')
 183         {
 184           free (s);
 185           /* Walk through the vector, shuffling args down by one, including
 186              the NULL terminator.  Can't use memcpy() here since the regions
 187              overlap, and memmove() might not be available. */
 188           while ((vector[0] = vector[1]) != NULL)
 189             {
 190               vector++;
 191             }
 192           break;
 193         }
 194     }
 195 }