environ.cc revision 1.1.1.1 
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
25gdb_environ &
26gdb_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
44gdb_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
64void
65gdb_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
80static bool
81match_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
91const char *
92gdb_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
105void
106gdb_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
129void
130gdb_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
157void
158gdb_environ::unset (const char *var)
159{
160  unset (var, true);
161}
162
163/* See gdbsupport/environ.h.  */
164
165char **
166gdb_environ::envp () const
167{
168  return const_cast<char **> (&m_environ_vector[0]);
169}
170
171/* See gdbsupport/environ.h.  */
172
173const std::set<std::string> &
174gdb_environ::user_set_env () const
175{
176  return m_user_set_env;
177}
178
179const std::set<std::string> &
180gdb_environ::user_unset_env () const
181{
182  return m_user_unset_env;
183}
184