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