gdbsupport/environ.cc

   1 /* environ.c -- library for manipulating environments for GNU.
   2
   3    Copyright (C) 1986-2023 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 #include "common-defs.h"
  19 #include "environ.h"
  20 #include <algorithm>
  21 #include <utility>
  22
  23 /* See gdbsupport/environ.h.  */
  24
  25 gdb_environ &
  26 gdb_environ::operator= (gdb_environ &&e)
  27 {
  28   /* Are we self-moving?  */
  29   if (&e == this)
  30     return *this;
  31
  32   this->clear ();
  33
  34   m_environ_vector = std::move (e.m_environ_vector);
  35   m_user_set_env = std::move (e.m_user_set_env);
  36   m_user_unset_env = std::move (e.m_user_unset_env);
  37   e.m_environ_vector.clear ();
  38   e.m_environ_vector.push_back (NULL);
  39   e.m_user_set_env.clear ();
  40   e.m_user_unset_env.clear ();
  41   return *this;
  42 }
  43
  44 /* See gdbsupport/environ.h.  */
  45
  46 gdb_environ gdb_environ::from_host_environ ()
  47 {
  48   extern char **environ;
  49   gdb_environ e;
  50
  51   if (environ == NULL)
  52     return e;
  53
  54   for (int i = 0; environ[i] != NULL; ++i)
  55     {
  56       /* Make sure we add the element before the last (NULL).  */
  57       e.m_environ_vector.insert (e.m_environ_vector.end () - 1,
  58                                  xstrdup (environ[i]));
  59     }
  60
  61   return e;
  62 }
  63
  64 /* See gdbsupport/environ.h.  */
  65
  66 void
  67 gdb_environ::clear ()
  68 {
  69   for (char *v : m_environ_vector)
  70     xfree (v);
  71   m_environ_vector.clear ();
  72   /* Always add the NULL element.  */
  73   m_environ_vector.push_back (NULL);
  74   m_user_set_env.clear ();
  75   m_user_unset_env.clear ();
  76 }
  77
  78 /* Helper function to check if STRING contains an environment variable
  79    assignment of VAR, i.e., if STRING starts with 'VAR='.  Return true
  80    if it contains, false otherwise.  */
  81
  82 static bool
  83 match_var_in_string (const char *string, const char *var, size_t var_len)
  84 {
  85   if (strncmp (string, var, var_len) == 0 && string[var_len] == '=')
  86     return true;
  87
  88   return false;
  89 }
  90
  91 /* See gdbsupport/environ.h.  */
  92
  93 const char *
  94 gdb_environ::get (const char *var) const
  95 {
  96   size_t len = strlen (var);
  97
  98   for (char *el : m_environ_vector)
  99     if (el != NULL && match_var_in_string (el, var, len))
 100       return &el[len + 1];
 101
 102   return NULL;
 103 }
 104
 105 /* See gdbsupport/environ.h.  */
 106
 107 void
 108 gdb_environ::set (const char *var, const char *value)
 109 {
 110   char *fullvar = concat (var, "=", value, (char *) NULL);
 111
 112   /* We have to unset the variable in the vector if it exists.  */
 113   unset (var, false);
 114
 115   /* Insert the element before the last one, which is always NULL.  */
 116   m_environ_vector.insert (m_environ_vector.end () - 1, fullvar);
 117
 118   /* Mark this environment variable as having been set by the user.
 119      This will be useful when we deal with setting environment
 120      variables on the remote target.  */
 121   m_user_set_env.insert (std::string (fullvar));
 122
 123   /* If this environment variable is marked as unset by the user, then
 124      remove it from the list, because now the user wants to set
 125      it.  */
 126   m_user_unset_env.erase (std::string (var));
 127 }
 128
 129 /* See gdbsupport/environ.h.  */
 130
 131 void
 132 gdb_environ::unset (const char *var, bool update_unset_list)
 133 {
 134   size_t len = strlen (var);
 135   std::vector<char *>::iterator it_env;
 136
 137   /* We iterate until '.end () - 1' because the last element is
 138      always NULL.  */
 139   for (it_env = m_environ_vector.begin ();
 140        it_env != m_environ_vector.end () - 1;
 141        ++it_env)
 142     if (match_var_in_string (*it_env, var, len))
 143       break;
 144
 145   if (it_env != m_environ_vector.end () - 1)
 146     {
 147       m_user_set_env.erase (std::string (*it_env));
 148       xfree (*it_env);
 149
 150       m_environ_vector.erase (it_env);
 151     }
 152
 153   if (update_unset_list)
 154     m_user_unset_env.insert (std::string (var));
 155 }
 156
 157 /* See gdbsupport/environ.h.  */
 158
 159 void
 160 gdb_environ::unset (const char *var)
 161 {
 162   unset (var, true);
 163 }
 164
 165 /* See gdbsupport/environ.h.  */
 166
 167 char **
 168 gdb_environ::envp () const
 169 {
 170   return const_cast<char **> (&m_environ_vector[0]);
 171 }
 172
 173 /* See gdbsupport/environ.h.  */
 174
 175 const std::set<std::string> &
 176 gdb_environ::user_set_env () const
 177 {
 178   return m_user_set_env;
 179 }
 180
 181 const std::set<std::string> &
 182 gdb_environ::user_unset_env () const
 183 {
 184   return m_user_unset_env;
 185 }