usr.sbin/autofs/defined.c

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