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 Lesser 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 #include <libgen.h>
  31
  32 #include "uci.h"
  33 #include "uci_internal.h"
  34
  35 __private void *uci_malloc(struct uci_context *ctx, size_t size)
  36 {
  37         void *ptr;
  38
  39         ptr = malloc(size);
  40         if (!ptr)
  41                 UCI_THROW(ctx, UCI_ERR_MEM);
  42         memset(ptr, 0, size);
  43
  44         return ptr;
  45 }
  46
  47 __private void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size)
  48 {
  49         ptr = realloc(ptr, size);
  50         if (!ptr)
  51                 UCI_THROW(ctx, UCI_ERR_MEM);
  52
  53         return ptr;
  54 }
  55
  56 __private char *uci_strdup(struct uci_context *ctx, const char *str)
  57 {
  58         char *ptr;
  59
  60         ptr = strdup(str);
  61         if (!ptr)
  62                 UCI_THROW(ctx, UCI_ERR_MEM);
  63
  64         return ptr;
  65 }
  66
  67 /*
  68  * validate strings for names and types, reject special characters
  69  * for names, only alphanum and _ is allowed (shell compatibility)
  70  * for types, we allow more characters
  71  */
  72 __private bool uci_validate_str(const char *str, bool name, bool package)
  73 {
  74         if (!*str)
  75                 return false;
  76
  77         for (; *str; str++) {
  78                 unsigned char c = *str;
  79
  80                 if (isalnum(c) || c == '_')
  81                         continue;
  82
  83                 if (c == '-' && package)
  84                         continue;
  85
  86                 if (name || (c < 33) || (c > 126))
  87                         return false;
  88         }
  89         return true;
  90 }
  91
  92 bool uci_validate_text(const char *str)
  93 {
  94         while (*str) {
  95                 unsigned char c = *str;
  96
  97                 if (c < 32 && c != '\t' && c != '\n' && c != '\r')
  98                         return false;
  99
 100                 str++;
 101         }
 102         return true;
 103 }
 104
 105 __private void uci_alloc_parse_context(struct uci_context *ctx)
 106 {
 107         ctx->pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 108 }
 109
 110 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str)
 111 {
 112         char *last = NULL;
 113         char *tmp;
 114
 115         UCI_HANDLE_ERR(ctx);
 116         UCI_ASSERT(ctx, str);
 117         UCI_ASSERT(ctx, ptr);
 118
 119         memset(ptr, 0, sizeof(struct uci_ptr));
 120
 121         /* value */
 122         last = strchr(str, '=');
 123         if (last) {
 124                 *last = 0;
 125                 last++;
 126                 ptr->value = last;
 127         }
 128
 129         ptr->package = strsep(&str, ".");
 130         if (!ptr->package)
 131                 goto error;
 132
 133         ptr->section = strsep(&str, ".");
 134         if (!ptr->section) {
 135                 ptr->target = UCI_TYPE_PACKAGE;
 136                 goto lastval;
 137         }
 138
 139         ptr->option = strsep(&str, ".");
 140         if (!ptr->option) {
 141                 ptr->target = UCI_TYPE_SECTION;
 142                 goto lastval;
 143         } else {
 144                 ptr->target = UCI_TYPE_OPTION;
 145         }
 146
 147         tmp = strsep(&str, ".");
 148         if (tmp)
 149                 goto error;
 150
 151 lastval:
 152         if (ptr->package && !uci_validate_package(ptr->package))
 153                 goto error;
 154         if (ptr->section && !uci_validate_name(ptr->section))
 155                 ptr->flags |= UCI_LOOKUP_EXTENDED;
 156         if (ptr->option && !uci_validate_name(ptr->option))
 157                 goto error;
 158         if (ptr->value && !uci_validate_text(ptr->value))
 159                 goto error;
 160
 161         return 0;
 162
 163 error:
 164         memset(ptr, 0, sizeof(struct uci_ptr));
 165         UCI_THROW(ctx, UCI_ERR_PARSE);
 166 }
 167
 168
 169 __private void uci_parse_error(struct uci_context *ctx, char *reason)
 170 {
 171         struct uci_parse_context *pctx = ctx->pctx;
 172
 173         pctx->reason = reason;
 174         pctx->byte = pctx_pos(pctx);
 175         UCI_THROW(ctx, UCI_ERR_PARSE);
 176 }
 177
 178
 179
 180 /*
 181  * open a stream and go to the right position
 182  *
 183  * note: when opening for write and seeking to the beginning of
 184  * the stream, truncate the file
 185  */
 186 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, const char *origfilename, int pos, bool write, bool create)
 187 {
 188         struct stat statbuf;
 189         FILE *file = NULL;
 190         int fd, ret;
 191         int flags = (write ? O_RDWR : O_RDONLY);
 192         mode_t mode = UCI_FILEMODE;
 193         char *name = NULL;
 194         char *filename2 = NULL;
 195
 196         if (create) {
 197                 flags |= O_CREAT;
 198                 if (origfilename) {
 199                         name = basename((char *) origfilename);
 200                 } else {
 201                         name = basename((char *) filename);
 202                 }
 203                 if ((asprintf(&filename2, "%s/%s", ctx->confdir, name) < 0) || !filename2) {
 204                         UCI_THROW(ctx, UCI_ERR_MEM);
 205                 } else {
 206                         if (stat(filename2, &statbuf) == 0)
 207                                 mode = statbuf.st_mode;
 208
 209                         free(filename2);
 210                 }
 211         }
 212
 213         if (!write && ((stat(filename, &statbuf) < 0) ||
 214                 ((statbuf.st_mode & S_IFMT) != S_IFREG))) {
 215                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 216         }
 217
 218         fd = open(filename, flags, mode);
 219         if (fd < 0)
 220                 goto error;
 221
 222         ret = flock(fd, (write ? LOCK_EX : LOCK_SH));
 223         if ((ret < 0) && (errno != ENOSYS))
 224                 goto error;
 225
 226         ret = lseek(fd, 0, pos);
 227
 228         if (ret < 0)
 229                 goto error;
 230
 231         file = fdopen(fd, (write ? "w+" : "r"));
 232         if (file)
 233                 goto done;
 234
 235 error:
 236         UCI_THROW(ctx, UCI_ERR_IO);
 237 done:
 238         return file;
 239 }
 240
 241 __private void uci_close_stream(FILE *stream)
 242 {
 243         int fd;
 244
 245         if (!stream)
 246                 return;
 247
 248         fflush(stream);
 249         fd = fileno(stream);
 250         flock(fd, LOCK_UN);
 251         fclose(stream);
 252 }
 253
 254