move export functionality to libuci
[project/uci.git] / file.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 the code for parsing uci config files
17 */
18
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <stdbool.h>
22 #include <stdio.h>
23 #include <ctype.h>
24
25 #define LINEBUF 32
26 #define LINEBUF_MAX 4096
27
28 /*
29 * Fetch a new line from the input stream and resize buffer if necessary
30 */
31 static void uci_getln(struct uci_context *ctx, int offset)
32 {
33 struct uci_parse_context *pctx = ctx->pctx;
34 char *p;
35 int ofs;
36
37 if (pctx->buf == NULL) {
38 pctx->buf = uci_malloc(ctx, LINEBUF);
39 pctx->bufsz = LINEBUF;
40 }
41
42 ofs = offset;
43 do {
44 p = &pctx->buf[ofs];
45 p[ofs] = 0;
46
47 p = fgets(p, pctx->bufsz - ofs, pctx->file);
48 if (!p || !*p)
49 return;
50
51 ofs += strlen(p);
52 if (pctx->buf[ofs - 1] == '\n') {
53 pctx->line++;
54 pctx->buf[ofs - 1] = 0;
55 return;
56 }
57
58 if (pctx->bufsz > LINEBUF_MAX/2) {
59 pctx->reason = "line too long";
60 pctx->byte = LINEBUF_MAX;
61 UCI_THROW(ctx, UCI_ERR_PARSE);
62 }
63
64 pctx->bufsz *= 2;
65 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
66 } while (1);
67 }
68
69 /*
70 * Clean up all extra memory used by the parser and exporter
71 */
72 static void uci_file_cleanup(struct uci_context *ctx)
73 {
74 struct uci_parse_context *pctx;
75
76 if (ctx->buf) {
77 free(ctx->buf);
78 ctx->bufsz = 0;
79 }
80
81 pctx = ctx->pctx;
82 if (!pctx)
83 return;
84
85 ctx->pctx = NULL;
86 if (pctx->cfg) {
87 uci_list_del(&pctx->cfg->list);
88 uci_drop_config(pctx->cfg);
89 }
90 if (pctx->buf)
91 free(pctx->buf);
92 if (pctx->file)
93 fclose(pctx->file);
94
95 free(pctx);
96 }
97
98 /*
99 * parse a character escaped by '\'
100 * returns true if the escaped character is to be parsed
101 * returns false if the escaped character is to be ignored
102 */
103 static inline bool parse_backslash(struct uci_context *ctx, char **str)
104 {
105 /* skip backslash */
106 *str += 1;
107
108 /* undecoded backslash at the end of line, fetch the next line */
109 if (!**str) {
110 *str += 1;
111 uci_getln(ctx, *str - ctx->pctx->buf);
112 return false;
113 }
114
115 /* FIXME: decode escaped char, necessary? */
116 return true;
117 }
118
119 /*
120 * move the string pointer forward until a non-whitespace character or
121 * EOL is reached
122 */
123 static void skip_whitespace(struct uci_context *ctx, char **str)
124 {
125 restart:
126 while (**str && isspace(**str))
127 *str += 1;
128
129 if (**str == '\\') {
130 if (!parse_backslash(ctx, str))
131 goto restart;
132 }
133 }
134
135 static inline void addc(char **dest, char **src)
136 {
137 **dest = **src;
138 *dest += 1;
139 *src += 1;
140 }
141
142 /*
143 * parse a double quoted string argument from the command line
144 */
145 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
146 {
147 char c;
148
149 /* skip quote character */
150 *str += 1;
151
152 while ((c = **str)) {
153 switch(c) {
154 case '"':
155 **target = 0;
156 *str += 1;
157 return;
158 case '\\':
159 if (!parse_backslash(ctx, str))
160 continue;
161 /* fall through */
162 default:
163 addc(target, str);
164 break;
165 }
166 }
167 ctx->pctx->reason = "unterminated \"";
168 ctx->pctx->byte = *str - ctx->pctx->buf;
169 UCI_THROW(ctx, UCI_ERR_PARSE);
170 }
171
172 /*
173 * parse a single quoted string argument from the command line
174 */
175 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
176 {
177 char c;
178 /* skip quote character */
179 *str += 1;
180
181 while ((c = **str)) {
182 switch(c) {
183 case '\'':
184 **target = 0;
185 *str += 1;
186 return;
187 default:
188 addc(target, str);
189 }
190 }
191 ctx->pctx->reason = "unterminated '";
192 ctx->pctx->byte = *str - ctx->pctx->buf;
193 UCI_THROW(ctx, UCI_ERR_PARSE);
194 }
195
196 /*
197 * parse a string from the command line and detect the quoting style
198 */
199 static void parse_str(struct uci_context *ctx, char **str, char **target)
200 {
201 do {
202 switch(**str) {
203 case '\'':
204 parse_single_quote(ctx, str, target);
205 break;
206 case '"':
207 parse_double_quote(ctx, str, target);
208 break;
209 case 0:
210 goto done;
211 case '\\':
212 if (!parse_backslash(ctx, str))
213 continue;
214 /* fall through */
215 default:
216 addc(target, str);
217 break;
218 }
219 } while (**str && !isspace(**str));
220 done:
221
222 /*
223 * if the string was unquoted and we've stopped at a whitespace
224 * character, skip to the next one, because the whitespace will
225 * be overwritten by a null byte here
226 */
227 if (**str)
228 *str += 1;
229
230 /* terminate the parsed string */
231 **target = 0;
232 }
233
234 /*
235 * extract the next argument from the command line
236 */
237 static char *next_arg(struct uci_context *ctx, char **str, bool required)
238 {
239 char *val;
240 char *ptr;
241
242 val = ptr = *str;
243 skip_whitespace(ctx, str);
244 parse_str(ctx, str, &ptr);
245 if (required && !*val) {
246 ctx->pctx->reason = "insufficient arguments";
247 ctx->pctx->byte = *str - ctx->pctx->buf;
248 UCI_THROW(ctx, UCI_ERR_PARSE);
249 }
250
251 return uci_strdup(ctx, val);
252 }
253
254 /*
255 * verify that the end of the line or command is reached.
256 * throw an error if extra arguments are given on the command line
257 */
258 static void assert_eol(struct uci_context *ctx, char **str)
259 {
260 char *tmp;
261
262 tmp = next_arg(ctx, str, false);
263 if (tmp && *tmp) {
264 ctx->pctx->reason = "too many arguments";
265 ctx->pctx->byte = tmp - ctx->pctx->buf;
266 UCI_THROW(ctx, UCI_ERR_PARSE);
267 }
268 }
269
270 /*
271 * switch to a different config, either triggered by uci_load, or by a
272 * 'package <...>' statement in the import file
273 */
274 static void uci_switch_config(struct uci_context *ctx)
275 {
276 struct uci_parse_context *pctx;
277 const char *name;
278
279 pctx = ctx->pctx;
280 name = pctx->name;
281
282 /* add the last config to main config file list */
283 if (pctx->cfg) {
284 uci_list_add(&ctx->root, &pctx->cfg->list);
285
286 pctx->cfg = NULL;
287 pctx->section = NULL;
288 }
289
290 if (!name)
291 return;
292
293 /*
294 * if an older config under the same name exists, unload it
295 * ignore errors here, e.g. if the config was not found
296 */
297 UCI_TRAP_SAVE(ctx, ignore);
298 uci_unload(ctx, name);
299 UCI_TRAP_RESTORE(ctx);
300 ignore:
301 ctx->errno = 0;
302
303 pctx->cfg = uci_alloc_config(ctx, name);
304 }
305
306 /*
307 * parse the 'package' uci command (next config package)
308 */
309 static void uci_parse_package(struct uci_context *ctx, char **str)
310 {
311 char *name = NULL;
312
313 /* command string null-terminated by strtok */
314 *str += strlen(*str) + 1;
315
316 UCI_TRAP_SAVE(ctx, error);
317 name = next_arg(ctx, str, true);
318 assert_eol(ctx, str);
319 ctx->pctx->name = name;
320 uci_switch_config(ctx);
321 UCI_TRAP_RESTORE(ctx);
322 return;
323
324 error:
325 if (name)
326 free(name);
327 UCI_THROW(ctx, ctx->errno);
328 }
329
330 /*
331 * parse the 'config' uci command (open a section)
332 */
333 static void uci_parse_config(struct uci_context *ctx, char **str)
334 {
335 char *name = NULL;
336 char *type = NULL;
337
338 if (!ctx->pctx->cfg) {
339 if (!ctx->pctx->name) {
340 ctx->pctx->byte = *str - ctx->pctx->buf;
341 ctx->pctx->reason = "attempting to import a file without a package name";
342 UCI_THROW(ctx, UCI_ERR_PARSE);
343 }
344 uci_switch_config(ctx);
345 }
346
347 /* command string null-terminated by strtok */
348 *str += strlen(*str) + 1;
349
350 UCI_TRAP_SAVE(ctx, error);
351 type = next_arg(ctx, str, true);
352 name = next_arg(ctx, str, false);
353 assert_eol(ctx, str);
354 ctx->pctx->section = uci_add_section(ctx->pctx->cfg, type, name);
355 UCI_TRAP_RESTORE(ctx);
356 return;
357
358 error:
359 if (name)
360 free(name);
361 if (type)
362 free(type);
363 UCI_THROW(ctx, ctx->errno);
364 }
365
366 /*
367 * parse the 'option' uci command (open a value)
368 */
369 static void uci_parse_option(struct uci_context *ctx, char **str)
370 {
371 char *name = NULL;
372 char *value = NULL;
373
374 if (!ctx->pctx->section) {
375 ctx->pctx->byte = *str - ctx->pctx->buf;
376 ctx->pctx->reason = "option command found before the first section";
377 UCI_THROW(ctx, UCI_ERR_PARSE);
378 }
379 /* command string null-terminated by strtok */
380 *str += strlen(*str) + 1;
381
382 UCI_TRAP_SAVE(ctx, error);
383 name = next_arg(ctx, str, true);
384 value = next_arg(ctx, str, true);
385 assert_eol(ctx, str);
386 uci_add_option(ctx->pctx->section, name, value);
387 UCI_TRAP_RESTORE(ctx);
388 return;
389
390 error:
391 if (name)
392 free(name);
393 if (value)
394 free(value);
395 UCI_THROW(ctx, ctx->errno);
396 }
397
398
399 /*
400 * parse a complete input line, split up combined commands by ';'
401 */
402 static void uci_parse_line(struct uci_context *ctx)
403 {
404 struct uci_parse_context *pctx = ctx->pctx;
405 char *word, *brk;
406
407 for (word = strtok_r(pctx->buf, ";", &brk);
408 word;
409 word = strtok_r(NULL, ";", &brk)) {
410
411 char *pbrk;
412 word = strtok_r(word, " \t", &pbrk);
413
414 switch(word[0]) {
415 case 'p':
416 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
417 uci_parse_package(ctx, &word);
418 break;
419 case 'c':
420 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
421 uci_parse_config(ctx, &word);
422 break;
423 case 'o':
424 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
425 uci_parse_option(ctx, &word);
426 break;
427 default:
428 pctx->reason = "unterminated command";
429 pctx->byte = word - pctx->buf;
430 UCI_THROW(ctx, UCI_ERR_PARSE);
431 break;
432 }
433 }
434 }
435
436 /* max number of characters that escaping adds to the string */
437 #define UCI_QUOTE_ESCAPE "'\\'"
438
439 /*
440 * escape an uci string for export
441 */
442 static char *uci_escape(struct uci_context *ctx, char *str)
443 {
444 char *s, *p, *t;
445 int pos = 0;
446
447 if (!ctx->buf) {
448 ctx->bufsz = LINEBUF;
449 ctx->buf = malloc(LINEBUF);
450 }
451
452 s = str;
453 p = strchr(str, '\'');
454 if (!p)
455 return str;
456
457 do {
458 int len = p - s;
459 if (len > 0) {
460 if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
461 ctx->bufsz *= 2;
462 ctx->buf = realloc(ctx->buf, ctx->bufsz);
463 if (!ctx->buf)
464 UCI_THROW(ctx, UCI_ERR_MEM);
465 }
466 memcpy(&ctx->buf[pos], s, len);
467 pos += len;
468 }
469 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
470 pos += sizeof(UCI_QUOTE_ESCAPE);
471 s = p + 1;
472 } while ((p = strchr(s, '\'')));
473
474 return ctx->buf;
475 }
476
477
478 /*
479 * export a single config package to a file stream
480 */
481 static void uci_export_config(struct uci_config *cfg, FILE *stream)
482 {
483 struct uci_context *ctx = cfg->ctx;
484 struct uci_section *s;
485 struct uci_option *o;
486
487 fprintf(stream, "package '%s'\n", uci_escape(ctx, cfg->name));
488 uci_foreach_entry(section, &cfg->sections, s) {
489 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, s->type));
490 fprintf(stream, " '%s'\n", uci_escape(ctx, s->name));
491 uci_foreach_entry(option, &s->options, o) {
492 fprintf(stream, "\toption '%s'", uci_escape(ctx, o->name));
493 fprintf(stream, " '%s'\n", uci_escape(ctx, o->value));
494 }
495 }
496 fprintf(stream, "\n");
497 }
498
499 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_config *cfg)
500 {
501 UCI_HANDLE_ERR(ctx);
502 UCI_ASSERT(ctx, stream != NULL);
503
504 if (cfg) {
505 uci_export_config(cfg, stream);
506 goto done;
507 }
508
509 uci_foreach_entry(config, &ctx->root, cfg) {
510 uci_export_config(cfg, stream);
511 }
512 done:
513 return 0;
514 }
515
516 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_config **cfg)
517 {
518 struct uci_parse_context *pctx;
519
520 /* make sure no memory from previous parse attempts is leaked */
521 uci_file_cleanup(ctx);
522
523 pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
524 ctx->pctx = pctx;
525 pctx->file = stream;
526
527 /*
528 * If 'name' was supplied, assume that the supplied stream does not contain
529 * the appropriate 'package <name>' string to specify the config name
530 * NB: the config file can still override the package name
531 */
532 if (name)
533 pctx->name = name;
534
535 while (!feof(pctx->file)) {
536 uci_getln(ctx, 0);
537 if (pctx->buf[0])
538 uci_parse_line(ctx);
539 }
540
541 if (cfg)
542 *cfg = pctx->cfg;
543
544 pctx->name = NULL;
545 uci_switch_config(ctx);
546
547 /* no error happened, we can get rid of the parser context now */
548 uci_file_cleanup(ctx);
549
550 return 0;
551 }
552
553 int uci_load(struct uci_context *ctx, const char *name, struct uci_config **cfg)
554 {
555 struct stat statbuf;
556 char *filename;
557 bool confpath;
558 FILE *file;
559
560 UCI_HANDLE_ERR(ctx);
561 UCI_ASSERT(ctx, name != NULL);
562
563 ignore:
564 ctx->errno = 0;
565
566 switch (name[0]) {
567 case '.':
568 case '/':
569 /* absolute/relative path outside of /etc/config */
570 filename = (char *) name;
571 confpath = false;
572 break;
573 default:
574 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
575 sprintf(filename, UCI_CONFDIR "/%s", name);
576 confpath = true;
577 break;
578 }
579
580 if ((stat(filename, &statbuf) < 0) ||
581 ((statbuf.st_mode & S_IFMT) != S_IFREG)) {
582 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
583 }
584
585 file = fopen(filename, "r");
586 if (filename != name)
587 free(filename);
588
589 if (!file)
590 UCI_THROW(ctx, UCI_ERR_IO);
591
592 return uci_import(ctx, file, name, cfg);
593 }
594