util.c

   1 /*
   2  * libuci - Library for the Unified Configuration Interface
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License version 2.1
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 /*
  16  * This file contains misc utility functions and wrappers to standard
  17  * functions, which throw exceptions upon failure.
  18  */
  19 #define _GNU_SOURCE
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <sys/file.h>
  23 #include <stdbool.h>
  24 #include <unistd.h>
  25 #include <ctype.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #include "uci.h"
  32 #include "uci_internal.h"
  33
  34 __plugin void *uci_malloc(struct uci_context *ctx, size_t size)
  35 {
  36         void *ptr;
  37
  38         ptr = malloc(size);
  39         if (!ptr)
  40                 UCI_THROW(ctx, UCI_ERR_MEM);
  41         memset(ptr, 0, size);
  42
  43         return ptr;
  44 }
  45
  46 __plugin void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size)
  47 {
  48         ptr = realloc(ptr, size);
  49         if (!ptr)
  50                 UCI_THROW(ctx, UCI_ERR_MEM);
  51
  52         return ptr;
  53 }
  54
  55 __plugin char *uci_strdup(struct uci_context *ctx, const char *str)
  56 {
  57         char *ptr;
  58
  59         ptr = strdup(str);
  60         if (!ptr)
  61                 UCI_THROW(ctx, UCI_ERR_MEM);
  62
  63         return ptr;
  64 }
  65
  66 /*
  67  * validate strings for names and types, reject special characters
  68  * for names, only alphanum and _ is allowed (shell compatibility)
  69  * for types, we allow more characters
  70  */
  71 __plugin bool uci_validate_str(const char *str, bool name)
  72 {
  73         if (!*str)
  74                 return false;
  75
  76         while (*str) {
  77                 unsigned char c = *str;
  78                 if (!isalnum(c) && c != '_') {
  79                         if (name || (c < 33) || (c > 126))
  80                                 return false;
  81                 }
  82                 str++;
  83         }
  84         return true;
  85 }
  86
  87 bool uci_validate_text(const char *str)
  88 {
  89         while (*str) {
  90                 unsigned char c = *str;
  91                 if ((c == '\r') || (c == '\n') ||
  92                         ((c < 32) && (c != '\t')))
  93                         return false;
  94                 str++;
  95         }
  96         return true;
  97 }
  98
  99 __private void uci_alloc_parse_context(struct uci_context *ctx)
 100 {
 101         ctx->pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 102 }
 103
 104 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str)
 105 {
 106         char *last = NULL;
 107         char *tmp;
 108
 109         UCI_HANDLE_ERR(ctx);
 110         UCI_ASSERT(ctx, str);
 111         UCI_ASSERT(ctx, ptr);
 112
 113         memset(ptr, 0, sizeof(struct uci_ptr));
 114
 115         /* value */
 116         last = strchr(str, '=');
 117         if (last) {
 118                 *last = 0;
 119                 last++;
 120                 ptr->value = last;
 121         }
 122
 123         ptr->package = strsep(&str, ".");
 124         if (!ptr->package)
 125                 goto error;
 126
 127         ptr->section = strsep(&str, ".");
 128         if (!ptr->section) {
 129                 ptr->target = UCI_TYPE_PACKAGE;
 130                 goto lastval;
 131         }
 132
 133         ptr->option = strsep(&str, ".");
 134         if (!ptr->option) {
 135                 ptr->target = UCI_TYPE_SECTION;
 136                 goto lastval;
 137         } else {
 138                 ptr->target = UCI_TYPE_OPTION;
 139         }
 140
 141         tmp = strsep(&str, ".");
 142         if (tmp)
 143                 goto error;
 144
 145 lastval:
 146         if (ptr->package && !uci_validate_package(ptr->package))
 147                 goto error;
 148         if (ptr->section && !uci_validate_name(ptr->section))
 149                 ptr->flags |= UCI_LOOKUP_EXTENDED;
 150         if (ptr->option && !uci_validate_name(ptr->option))
 151                 goto error;
 152         if (ptr->value && !uci_validate_text(ptr->value))
 153                 goto error;
 154
 155         return 0;
 156
 157 error:
 158         memset(ptr, 0, sizeof(struct uci_ptr));
 159         UCI_THROW(ctx, UCI_ERR_PARSE);
 160 }
 161
 162
 163 __private void uci_parse_error(struct uci_context *ctx, char *pos, char *reason)
 164 {
 165         struct uci_parse_context *pctx = ctx->pctx;
 166
 167         pctx->reason = reason;
 168         pctx->byte = pos - pctx->buf;
 169         UCI_THROW(ctx, UCI_ERR_PARSE);
 170 }
 171
 172
 173
 174 /*
 175  * open a stream and go to the right position
 176  *
 177  * note: when opening for write and seeking to the beginning of
 178  * the stream, truncate the file
 179  */
 180 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, int pos, bool write, bool create)
 181 {
 182         struct stat statbuf;
 183         FILE *file = NULL;
 184         int fd, ret;
 185         int mode = (write ? O_RDWR : O_RDONLY);
 186
 187         if (create)
 188                 mode |= O_CREAT;
 189
 190         if (!write && ((stat(filename, &statbuf) < 0) ||
 191                 ((statbuf.st_mode &  S_IFMT) != S_IFREG))) {
 192                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 193         }
 194
 195         fd = open(filename, mode, UCI_FILEMODE);
 196         if (fd < 0)
 197                 goto error;
 198
 199         ret = flock(fd, (write ? LOCK_EX : LOCK_SH));
 200         if ((ret < 0) && (errno != ENOSYS))
 201                 goto error;
 202
 203         ret = lseek(fd, 0, pos);
 204
 205         if (ret < 0)
 206                 goto error;
 207
 208         file = fdopen(fd, (write ? "w+" : "r"));
 209         if (file)
 210                 goto done;
 211
 212 error:
 213         UCI_THROW(ctx, UCI_ERR_IO);
 214 done:
 215         return file;
 216 }
 217
 218 __private void uci_close_stream(FILE *stream)
 219 {
 220         int fd;
 221
 222         if (!stream)
 223                 return;
 224
 225         fflush(stream);
 226         fd = fileno(stream);
 227         flock(fd, LOCK_UN);
 228         fclose(stream);
 229 }
 230
 231