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