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