usr.sbin/autofs/defined.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2016 The DragonFly Project
   5  * Copyright (c) 2014 The FreeBSD Foundation
   6  * All rights reserved.
   7  *
   8  * This software was developed by Edward Tomasz Napierala under sponsorship
   9  * from the FreeBSD Foundation.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  */
  33
  34 /*
  35  * All the "defined" stuff is for handling variables,
  36  * such as ${OSNAME}, in maps.
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/utsname.h>
  41 #include <assert.h>
  42 #include <ctype.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47
  48 #include "common.h"
  49
  50 static TAILQ_HEAD(, defined_value)      defined_values;
  51
  52 static const char *
  53 defined_find(const char *name)
  54 {
  55         struct defined_value *d;
  56
  57         TAILQ_FOREACH(d, &defined_values, d_next) {
  58                 if (strcmp(d->d_name, name) == 0)
  59                         return (d->d_value);
  60         }
  61
  62         return (NULL);
  63 }
  64
  65 char *
  66 defined_expand(const char *string)
  67 {
  68         const char *value;
  69         char c, *expanded, *name;
  70         int i, ret, before_len = 0, name_off = 0, name_len = 0, after_off = 0;
  71         bool backslashed = false, bracketed = false;
  72
  73         expanded = checked_strdup(string);
  74
  75         for (i = 0; string[i] != '\0'; i++) {
  76                 c = string[i];
  77                 if (c == '\\' && backslashed == false) {
  78                         backslashed = true;
  79                         continue;
  80                 }
  81                 if (backslashed) {
  82                         backslashed = false;
  83                         continue;
  84                 }
  85                 backslashed = false;
  86                 if (c != '$')
  87                         continue;
  88
  89                 /*
  90                  * The 'before_len' variable contains the number
  91                  * of characters before the '$'.
  92                  */
  93                 before_len = i;
  94                 assert(i + 1 < (int)strlen(string));
  95                 if (string[i + 1] == '{')
  96                         bracketed = true;
  97
  98                 if (string[i + 1] == '\0') {
  99                         log_warnx("truncated variable");
 100                         return (NULL);
 101                 }
 102
 103                 /*
 104                  * Skip '$'.
 105                  */
 106                 i++;
 107
 108                 if (bracketed) {
 109                         if (string[i + 1] == '\0') {
 110                                 log_warnx("truncated variable");
 111                                 return (NULL);
 112                         }
 113
 114                         /*
 115                          * Skip '{'.
 116                          */
 117                         i++;
 118                 }
 119
 120                 /*
 121                  * The 'name_off' variable contains the number
 122                  * of characters before the variable name,
 123                  * including the "$" or "${".
 124                  */
 125                 name_off = i;
 126
 127                 for (; string[i] != '\0'; i++) {
 128                         c = string[i];
 129                         /*
 130                          * XXX: Decide on the set of characters that can be
 131                          *      used in a variable name.
 132                          */
 133                         if (isalnum(c) || c == '_')
 134                                 continue;
 135
 136                         /*
 137                          * End of variable name.
 138                          */
 139                         if (bracketed) {
 140                                 if (c != '}')
 141                                         continue;
 142
 143                                 /*
 144                                  * The 'after_off' variable contains the number
 145                                  * of characters before the rest of the string,
 146                                  * i.e. after the variable name.
 147                                  */
 148                                 after_off = i + 1;
 149                                 assert(i > 1);
 150                                 assert(i - 1 > name_off);
 151                                 name_len = i - name_off;
 152                                 break;
 153                         }
 154
 155                         after_off = i;
 156                         assert(i > 1);
 157                         assert(i > name_off);
 158                         name_len = i - name_off;
 159                         break;
 160                 }
 161
 162                 name = strndup(string + name_off, name_len);
 163                 if (name == NULL)
 164                         log_err(1, "strndup");
 165                 value = defined_find(name);
 166                 if (value == NULL) {
 167                         log_warnx("undefined variable ${%s}", name);
 168                         return (NULL);
 169                 }
 170
 171                 /*
 172                  * Concatenate it back.
 173                  */
 174                 ret = asprintf(&expanded, "%.*s%s%s",
 175                     before_len, string, value, string + after_off);
 176                 if (ret < 0)
 177                         log_err(1, "asprintf");
 178
 179                 //log_debugx("\"%s\" expanded to \"%s\"", string, expanded);
 180                 free(name);
 181
 182                 /*
 183                  * Figure out where to start searching for next variable.
 184                  */
 185                 string = expanded;
 186                 i = before_len + strlen(value);
 187                 backslashed = bracketed = false;
 188                 before_len = name_off = name_len = after_off = 0;
 189                 assert(i <= (int)strlen(string));
 190         }
 191
 192         if (before_len != 0 || name_off != 0 || name_len != 0 || after_off != 0) {
 193                 log_warnx("truncated variable");
 194                 return (NULL);
 195         }
 196
 197         return (expanded);
 198 }
 199
 200 static void
 201 defined_add(const char *name, const char *value)
 202 {
 203         struct defined_value *d;
 204         const char *found;
 205
 206         found = defined_find(name);
 207         if (found != NULL)
 208                 log_errx(1, "variable %s already defined", name);
 209
 210         log_debugx("defining variable %s=%s", name, value);
 211
 212         d = calloc(1, sizeof(*d));
 213         if (d == NULL)
 214                 log_err(1, "calloc");
 215         d->d_name = checked_strdup(name);
 216         d->d_value = checked_strdup(value);
 217
 218         TAILQ_INSERT_TAIL(&defined_values, d, d_next);
 219 }
 220
 221 void
 222 defined_parse_and_add(char *def)
 223 {
 224         char *name, *value;
 225
 226         value = def;
 227         name = strsep(&value, "=");
 228
 229         if (value == NULL || value[0] == '\0')
 230                 log_errx(1, "missing variable value");
 231         if (name == NULL || name[0] == '\0')
 232                 log_errx(1, "missing variable name");
 233
 234         defined_add(name, value);
 235 }
 236
 237 void
 238 defined_init(void)
 239 {
 240         struct utsname name;
 241         int error;
 242
 243         TAILQ_INIT(&defined_values);
 244
 245         error = uname(&name);
 246         if (error != 0)
 247                 log_err(1, "uname");
 248
 249         defined_add("ARCH", name.machine);
 250         defined_add("CPU", name.machine);
 251         defined_add("DOLLAR", "$");
 252         defined_add("HOST", name.nodename);
 253         defined_add("OSNAME", name.sysname);
 254         defined_add("OSREL", name.release);
 255         defined_add("OSVERS", name.version);
 256 }