gdbsupport/environ.cc

   1 /* environ.c -- library for manipulating environments for GNU.
   2
   3    Copyright (C) 1986-2020 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   m_environ_vector = std::move (e.m_environ_vector);
  33   m_user_set_env = std::move (e.m_user_set_env);
  34   m_user_unset_env = std::move (e.m_user_unset_env);
  35   e.m_environ_vector.clear ();
  36   e.m_environ_vector.push_back (NULL);
  37   e.m_user_set_env.clear ();
  38   e.m_user_unset_env.clear ();
  39   return *this;
  40 }
  41
  42 /* See gdbsupport/environ.h.  */
  43
  44 gdb_environ gdb_environ::from_host_environ ()
  45 {
  46   extern char **environ;
  47   gdb_environ e;
  48
  49   if (environ == NULL)
  50     return e;
  51
  52   for (int i = 0; environ[i] != NULL; ++i)
  53     {
  54       /* Make sure we add the element before the last (NULL).  */
  55       e.m_environ_vector.insert (e.m_environ_vector.end () - 1,
  56                                  xstrdup (environ[i]));
  57     }
  58
  59   return e;
  60 }
  61
  62 /* See gdbsupport/environ.h.  */
  63
  64 void
  65 gdb_environ::clear ()
  66 {
  67   for (char *v : m_environ_vector)
  68     xfree (v);
  69   m_environ_vector.clear ();
  70   /* Always add the NULL element.  */
  71   m_environ_vector.push_back (NULL);
  72   m_user_set_env.clear ();
  73   m_user_unset_env.clear ();
  74 }
  75
  76 /* Helper function to check if STRING contains an environment variable
  77    assignment of VAR, i.e., if STRING starts with 'VAR='.  Return true
  78    if it contains, false otherwise.  */
  79
  80 static bool
  81 match_var_in_string (const char *string, const char *var, size_t var_len)
  82 {
  83   if (strncmp (string, var, var_len) == 0 && string[var_len] == '=')
  84     return true;
  85
  86   return false;
  87 }
  88
  89 /* See gdbsupport/environ.h.  */
  90
  91 const char *
  92 gdb_environ::get (const char *var) const
  93 {
  94   size_t len = strlen (var);
  95
  96   for (char *el : m_environ_vector)
  97     if (el != NULL && match_var_in_string (el, var, len))
  98       return &el[len + 1];
  99
 100   return NULL;
 101 }
 102
 103 /* See gdbsupport/environ.h.  */
 104
 105 void
 106 gdb_environ::set (const char *var, const char *value)
 107 {
 108   char *fullvar = concat (var, "=", value, (char *) NULL);
 109
 110   /* We have to unset the variable in the vector if it exists.  */
 111   unset (var, false);
 112
 113   /* Insert the element before the last one, which is always NULL.  */
 114   m_environ_vector.insert (m_environ_vector.end () - 1, fullvar);
 115
 116   /* Mark this environment variable as having been set by the user.
 117      This will be useful when we deal with setting environment
 118      variables on the remote target.  */
 119   m_user_set_env.insert (std::string (fullvar));
 120
 121   /* If this environment variable is marked as unset by the user, then
 122      remove it from the list, because now the user wants to set
 123      it.  */
 124   m_user_unset_env.erase (std::string (var));
 125 }
 126
 127 /* See gdbsupport/environ.h.  */
 128
 129 void
 130 gdb_environ::unset (const char *var, bool update_unset_list)
 131 {
 132   size_t len = strlen (var);
 133   std::vector<char *>::iterator it_env;
 134
 135   /* We iterate until '.end () - 1' because the last element is
 136      always NULL.  */
 137   for (it_env = m_environ_vector.begin ();
 138        it_env != m_environ_vector.end () - 1;
 139        ++it_env)
 140     if (match_var_in_string (*it_env, var, len))
 141       break;
 142
 143   if (it_env != m_environ_vector.end () - 1)
 144     {
 145       m_user_set_env.erase (std::string (*it_env));
 146       xfree (*it_env);
 147
 148       m_environ_vector.erase (it_env);
 149     }
 150
 151   if (update_unset_list)
 152     m_user_unset_env.insert (std::string (var));
 153 }
 154
 155 /* See gdbsupport/environ.h.  */
 156
 157 void
 158 gdb_environ::unset (const char *var)
 159 {
 160   unset (var, true);
 161 }
 162
 163 /* See gdbsupport/environ.h.  */
 164
 165 char **
 166 gdb_environ::envp () const
 167 {
 168   return const_cast<char **> (&m_environ_vector[0]);
 169 }
 170
 171 /* See gdbsupport/environ.h.  */
 172
 173 const std::set<std::string> &
 174 gdb_environ::user_set_env () const
 175 {
 176   return m_user_set_env;
 177 }
 178
 179 const std::set<std::string> &
 180 gdb_environ::user_unset_env () const
 181 {
 182   return m_user_unset_env;
 183 }