1  /* environment.c  --  Function for extracting data from the OpenVPN environment table
 2   *
 3   *  GPLv2 only - Copyright (C) 2008 - 2012
 4   *               David Sommerseth <dazo@users.sourceforge.net>
 5   *
 6   *  This program is free software; you can redistribute it and/or
 7   *  modify it under the terms of the GNU General Public License
 8   *  as published by the Free Software Foundation; version 2
 9   *  of the License.
10   *
11   *  This program is distributed in the hope that it will be useful,
12   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   *  GNU General Public License for more details.
15   *
16   *  You should have received a copy of the GNU General Public License
17   *  along with this program; if not, write to the Free Software
18   *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
19   *
20   */
21  
22  /**
23   * @file   environment.c
24   * @author David Sommerseth <dazo@users.sourceforge.net>
25   * @date   2008-08-06
26   *
27   * @brief  Function for extracting data from the OpenVPN environment table.
28   *
29   */
30  
31  #include <stdio.h>
32  #include <stdarg.h>
33  #include <string.h>
34  
35  #include <eurephia_nullsafe.h>
36  #include <eurephia_context.h>
37  #include <eurephia_log.h>
38  
39  /**
40   * get_env() retrieve values from the openvpn environment table
41   *
42   * @param ctx        eurephiaCTX context
43   * @param logmasking If 1, the value will be masked in the log files (eg. to hide password)
44   * @param len        How many bytes to copy out of the environment variable
45   * @param envp       the environment table
46   * @param fmt        The key to look for (stdarg)
47   *
48   * @return Returns a const char * with the value, or NULL if not found
49   */
50  char *get_env(eurephiaCTX *ctx, int logmasking, size_t len,
51                const char *envp[], const char *fmt, ... )
52  {
53          if (envp) {
54                  va_list ap;
55                  char key[384];
56                  int keylen = 0;
57                  int i;
58  
59                  // Build up the key we are looking for
60                  memset(&key, 0, 384);
61                  va_start(ap, fmt);
62                  vsnprintf(key, 382, fmt, ap);
63  
64                  // Find the key
65                  keylen = strlen (key);
66                  for (i = 0; envp[i]; ++i) {
67                          if (!strncmp (envp[i], key, keylen)) {
68                                  const char *cp = envp[i] + keylen;
69                                  char *ret = NULL;
70                                  if (*cp == '=') {
71                                          ret = malloc_nullsafe(ctx, len+2);
72                                          strncpy(ret, cp+1, len);
73  #ifdef ENABLE_DEBUG
74                                          int do_mask = 0;
75  #ifndef SHOW_SECRETS
76                                          do_mask = logmasking;
77  #endif
78                                          if( ctx != NULL ) {
79                                                  DEBUG(ctx, 30, "Function call: get_env(envp, '%s') == '%s'",
80                                                        key, (do_mask == 0 ? ret : "xxxxxxxxxxxxxx"));
81                                          }
82  #endif
83                                          return ret;
84                                  }
85                          }
86                  }
87                  if( ctx != NULL ) {
88                          DEBUG(ctx, 15, "Function call: get_env(envp, '%s') -- environment variable not found",
89                                key);
90                  }
91                  va_end(ap);
92          }
93          return NULL;
94  }