a78c5a7abc8fc9dd07d7844a010624966a7d30f9
[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 <unistd.h>
23 #include <fcntl.h>
24 #include <stdio.h>
25 #include <ctype.h>
26
27 #define LINEBUF 32
28 #define LINEBUF_MAX 4096
29
30 static void uci_parse_error(struct uci_context *ctx, char *pos, char *reason)
31 {
32 struct uci_parse_context *pctx = ctx->pctx;
33
34 pctx->reason = reason;
35 pctx->byte = pos - pctx->buf;
36 UCI_THROW(ctx, UCI_ERR_PARSE);
37 }
38
39 /*
40 * Fetch a new line from the input stream and resize buffer if necessary
41 */
42 static void uci_getln(struct uci_context *ctx, int offset)
43 {
44 struct uci_parse_context *pctx = ctx->pctx;
45 char *p;
46 int ofs;
47
48 if (pctx->buf == NULL) {
49 pctx->buf = uci_malloc(ctx, LINEBUF);
50 pctx->bufsz = LINEBUF;
51 }
52
53 ofs = offset;
54 do {
55 p = &pctx->buf[ofs];
56 p[ofs] = 0;
57
58 p = fgets(p, pctx->bufsz - ofs, pctx->file);
59 if (!p || !*p)
60 return;
61
62 ofs += strlen(p);
63 if (pctx->buf[ofs - 1] == '\n') {
64 pctx->line++;
65 pctx->buf[ofs - 1] = 0;
66 return;
67 }
68
69 if (pctx->bufsz > LINEBUF_MAX/2)
70 uci_parse_error(ctx, p, "line too long");
71
72 pctx->bufsz *= 2;
73 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
74 } while (1);
75 }
76
77 /*
78 * Clean up all extra memory used by the parser and exporter
79 */
80 static void uci_file_cleanup(struct uci_context *ctx)
81 {
82 struct uci_parse_context *pctx;
83
84 if (ctx->buf) {
85 free(ctx->buf);
86 ctx->buf = NULL;
87 ctx->bufsz = 0;
88 }
89
90 pctx = ctx->pctx;
91 if (!pctx)
92 return;
93
94 ctx->pctx = NULL;
95 if (pctx->package)
96 uci_free_package(pctx->package);
97
98 if (pctx->buf)
99 free(pctx->buf);
100 if (pctx->file)
101 fclose(pctx->file);
102
103 free(pctx);
104 }
105
106 /*
107 * parse a character escaped by '\'
108 * returns true if the escaped character is to be parsed
109 * returns false if the escaped character is to be ignored
110 */
111 static inline bool parse_backslash(struct uci_context *ctx, char **str)
112 {
113 /* skip backslash */
114 *str += 1;
115
116 /* undecoded backslash at the end of line, fetch the next line */
117 if (!**str) {
118 *str += 1;
119 uci_getln(ctx, *str - ctx->pctx->buf);
120 return false;
121 }
122
123 /* FIXME: decode escaped char, necessary? */
124 return true;
125 }
126
127 /*
128 * move the string pointer forward until a non-whitespace character or
129 * EOL is reached
130 */
131 static void skip_whitespace(struct uci_context *ctx, char **str)
132 {
133 restart:
134 while (**str && isspace(**str))
135 *str += 1;
136
137 if (**str == '\\') {
138 if (!parse_backslash(ctx, str))
139 goto restart;
140 }
141 }
142
143 static inline void addc(char **dest, char **src)
144 {
145 **dest = **src;
146 *dest += 1;
147 *src += 1;
148 }
149
150 /*
151 * parse a double quoted string argument from the command line
152 */
153 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
154 {
155 char c;
156
157 /* skip quote character */
158 *str += 1;
159
160 while ((c = **str)) {
161 switch(c) {
162 case '"':
163 **target = 0;
164 *str += 1;
165 return;
166 case '\\':
167 if (!parse_backslash(ctx, str))
168 continue;
169 /* fall through */
170 default:
171 addc(target, str);
172 break;
173 }
174 }
175 uci_parse_error(ctx, *str, "unterminated \"");
176 }
177
178 /*
179 * parse a single quoted string argument from the command line
180 */
181 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
182 {
183 char c;
184 /* skip quote character */
185 *str += 1;
186
187 while ((c = **str)) {
188 switch(c) {
189 case '\'':
190 **target = 0;
191 *str += 1;
192 return;
193 default:
194 addc(target, str);
195 }
196 }
197 uci_parse_error(ctx, *str, "unterminated '");
198 }
199
200 /*
201 * parse a string from the command line and detect the quoting style
202 */
203 static void parse_str(struct uci_context *ctx, char **str, char **target)
204 {
205 do {
206 switch(**str) {
207 case '\'':
208 parse_single_quote(ctx, str, target);
209 break;
210 case '"':
211 parse_double_quote(ctx, str, target);
212 break;
213 case 0:
214 goto done;
215 case '\\':
216 if (!parse_backslash(ctx, str))
217 continue;
218 /* fall through */
219 default:
220 addc(target, str);
221 break;
222 }
223 } while (**str && !isspace(**str));
224 done:
225
226 /*
227 * if the string was unquoted and we've stopped at a whitespace
228 * character, skip to the next one, because the whitespace will
229 * be overwritten by a null byte here
230 */
231 if (**str)
232 *str += 1;
233
234 /* terminate the parsed string */
235 **target = 0;
236 }
237
238 /*
239 * extract the next argument from the command line
240 */
241 static char *next_arg(struct uci_context *ctx, char **str, bool required)
242 {
243 char *val;
244 char *ptr;
245
246 val = ptr = *str;
247 skip_whitespace(ctx, str);
248 parse_str(ctx, str, &ptr);
249 if (required && !*val)
250 uci_parse_error(ctx, *str, "insufficient arguments");
251
252 return val;
253 }
254
255 /*
256 * verify that the end of the line or command is reached.
257 * throw an error if extra arguments are given on the command line
258 */
259 static void assert_eol(struct uci_context *ctx, char **str)
260 {
261 char *tmp;
262
263 tmp = next_arg(ctx, str, false);
264 if (tmp && *tmp)
265 uci_parse_error(ctx, *str, "too many arguments");
266 }
267
268 /*
269 * switch to a different config, either triggered by uci_load, or by a
270 * 'package <...>' statement in the import file
271 */
272 static void uci_switch_config(struct uci_context *ctx)
273 {
274 struct uci_parse_context *pctx;
275 struct uci_element *e;
276 const char *name;
277
278 pctx = ctx->pctx;
279 name = pctx->name;
280
281 /* add the last config to main config file list */
282 if (pctx->package) {
283 uci_list_add(&ctx->root, &pctx->package->e.list);
284
285 pctx->package = NULL;
286 pctx->section = NULL;
287 }
288
289 if (!name)
290 return;
291
292 /*
293 * if an older config under the same name exists, unload it
294 * ignore errors here, e.g. if the config was not found
295 */
296 e = uci_lookup_list(ctx, &ctx->root, name);
297 if (e)
298 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
299 pctx->package = uci_alloc_package(ctx, name);
300 }
301
302 /*
303 * parse the 'package' uci command (next config package)
304 */
305 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
306 {
307 char *name = NULL;
308
309 /* command string null-terminated by strtok */
310 *str += strlen(*str) + 1;
311
312 name = next_arg(ctx, str, true);
313 assert_eol(ctx, str);
314 if (single)
315 return;
316
317 ctx->pctx->name = name;
318 uci_switch_config(ctx);
319 }
320
321 /*
322 * parse the 'config' uci command (open a section)
323 */
324 static void uci_parse_config(struct uci_context *ctx, char **str)
325 {
326 char *name = NULL;
327 char *type = NULL;
328
329 if (!ctx->pctx->package) {
330 if (!ctx->pctx->name)
331 uci_parse_error(ctx, *str, "attempting to import a file without a package name");
332
333 uci_switch_config(ctx);
334 }
335
336 /* command string null-terminated by strtok */
337 *str += strlen(*str) + 1;
338
339 type = next_arg(ctx, str, true);
340 name = next_arg(ctx, str, false);
341 assert_eol(ctx, str);
342 ctx->pctx->section = uci_alloc_section(ctx->pctx->package, type, name);
343 }
344
345 /*
346 * parse the 'option' uci command (open a value)
347 */
348 static void uci_parse_option(struct uci_context *ctx, char **str)
349 {
350 char *name = NULL;
351 char *value = NULL;
352
353 if (!ctx->pctx->section)
354 uci_parse_error(ctx, *str, "option command found before the first section");
355
356 /* command string null-terminated by strtok */
357 *str += strlen(*str) + 1;
358
359 name = next_arg(ctx, str, true);
360 value = next_arg(ctx, str, true);
361 assert_eol(ctx, str);
362 uci_alloc_option(ctx->pctx->section, name, value);
363 }
364
365
366 /*
367 * parse a complete input line, split up combined commands by ';'
368 */
369 static void uci_parse_line(struct uci_context *ctx, bool single)
370 {
371 struct uci_parse_context *pctx = ctx->pctx;
372 char *word, *brk = NULL;
373
374 for (word = strtok_r(pctx->buf, ";", &brk);
375 word;
376 word = strtok_r(NULL, ";", &brk)) {
377
378 char *pbrk = NULL;
379 word = strtok_r(word, " \t", &pbrk);
380
381 switch(word[0]) {
382 case 'p':
383 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
384 uci_parse_package(ctx, &word, single);
385 break;
386 case 'c':
387 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
388 uci_parse_config(ctx, &word);
389 break;
390 case 'o':
391 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
392 uci_parse_option(ctx, &word);
393 break;
394 default:
395 uci_parse_error(ctx, word, "unterminated command");
396 break;
397 }
398 }
399 }
400
401 /* max number of characters that escaping adds to the string */
402 #define UCI_QUOTE_ESCAPE "'\\''"
403
404 /*
405 * escape an uci string for export
406 */
407 static char *uci_escape(struct uci_context *ctx, char *str)
408 {
409 char *s, *p;
410 int pos = 0;
411
412 if (!ctx->buf) {
413 ctx->bufsz = LINEBUF;
414 ctx->buf = malloc(LINEBUF);
415 }
416
417 s = str;
418 p = strchr(str, '\'');
419 if (!p)
420 return str;
421
422 do {
423 int len = p - s;
424 if (len > 0) {
425 if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
426 ctx->bufsz *= 2;
427 ctx->buf = realloc(ctx->buf, ctx->bufsz);
428 if (!ctx->buf)
429 UCI_THROW(ctx, UCI_ERR_MEM);
430 }
431 memcpy(&ctx->buf[pos], s, len);
432 pos += len;
433 }
434 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
435 pos += sizeof(UCI_QUOTE_ESCAPE);
436 s = p + 1;
437 } while ((p = strchr(s, '\'')));
438
439 return ctx->buf;
440 }
441
442
443 /*
444 * export a single config package to a file stream
445 */
446 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
447 {
448 struct uci_context *ctx = p->ctx;
449 struct uci_element *s, *o;
450
451 if (header)
452 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
453 uci_foreach_element(&p->sections, s) {
454 struct uci_section *sec = uci_to_section(s);
455 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
456 fprintf(stream, " '%s'\n", uci_escape(ctx, sec->e.name));
457 uci_foreach_element(&sec->options, o) {
458 struct uci_option *opt = uci_to_option(o);
459 fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
460 fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
461 }
462 }
463 fprintf(stream, "\n");
464 }
465
466 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
467 {
468 struct uci_element *e;
469
470 UCI_HANDLE_ERR(ctx);
471 UCI_ASSERT(ctx, stream != NULL);
472
473 if (package)
474 uci_export_package(package, stream, header);
475 else {
476 uci_foreach_element(&ctx->root, e) {
477 uci_export_package(uci_to_package(e), stream, header);
478 }
479 }
480
481 return 0;
482 }
483
484 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
485 {
486 struct uci_parse_context *pctx;
487
488 /* make sure no memory from previous parse attempts is leaked */
489 uci_file_cleanup(ctx);
490
491 pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
492 ctx->pctx = pctx;
493 pctx->file = stream;
494
495 /*
496 * If 'name' was supplied, assume that the supplied stream does not contain
497 * the appropriate 'package <name>' string to specify the config name
498 * NB: the config file can still override the package name
499 */
500 if (name)
501 pctx->name = name;
502
503 while (!feof(pctx->file)) {
504 uci_getln(ctx, 0);
505 if (pctx->buf[0])
506 uci_parse_line(ctx, single);
507 }
508
509 if (package)
510 *package = pctx->package;
511
512 pctx->name = NULL;
513 uci_switch_config(ctx);
514
515 /* no error happened, we can get rid of the parser context now */
516 uci_file_cleanup(ctx);
517
518 return 0;
519 }
520
521 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
522 {
523 struct stat statbuf;
524 char *filename;
525 bool confdir;
526 FILE *file;
527 int fd;
528
529 UCI_HANDLE_ERR(ctx);
530 UCI_ASSERT(ctx, name != NULL);
531
532 switch (name[0]) {
533 case '.':
534 if (name[1] != '/')
535 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
536 /* fall through */
537 case '/':
538 /* absolute/relative path outside of /etc/config */
539 filename = uci_strdup(ctx, name);
540 name = strrchr(name, '/') + 1;
541 confdir = false;
542 break;
543 default:
544 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
545 sprintf(filename, UCI_CONFDIR "/%s", name);
546 confdir = true;
547 break;
548 }
549
550 if ((stat(filename, &statbuf) < 0) ||
551 ((statbuf.st_mode & S_IFMT) != S_IFREG)) {
552 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
553 }
554
555 fd = open(filename, O_RDONLY);
556 if (fd <= 0)
557 UCI_THROW(ctx, UCI_ERR_IO);
558
559 if (flock(fd, LOCK_SH) < 0)
560 UCI_THROW(ctx, UCI_ERR_IO);
561
562 file = fdopen(fd, "r");
563 if (!file)
564 UCI_THROW(ctx, UCI_ERR_IO);
565
566 ctx->errno = 0;
567 UCI_TRAP_SAVE(ctx, done);
568 uci_import(ctx, file, name, package, true);
569 UCI_TRAP_RESTORE(ctx);
570
571 if (*package) {
572 (*package)->path = filename;
573 (*package)->confdir = confdir;
574 }
575
576 done:
577 flock(fd, LOCK_UN);
578 fclose(file);
579 return ctx->errno;
580 }
581
582 int uci_commit(struct uci_context *ctx, struct uci_package *p)
583 {
584 FILE *f = NULL;
585 int fd = 0;
586 int err = UCI_ERR_IO;
587
588 UCI_HANDLE_ERR(ctx);
589 UCI_ASSERT(ctx, p != NULL);
590 UCI_ASSERT(ctx, p->path != NULL);
591
592 fd = open(p->path, O_RDWR);
593 if (fd < 0)
594 goto done;
595
596 if (flock(fd, LOCK_EX) < 0)
597 goto done;
598
599 ftruncate(fd, 0);
600 f = fdopen(fd, "w");
601 if (!f)
602 goto done;
603
604 UCI_TRAP_SAVE(ctx, done);
605 uci_export(ctx, f, p, false);
606 UCI_TRAP_RESTORE(ctx);
607
608 done:
609 if (f)
610 fclose(f);
611 else if (fd > 0)
612 close(fd);
613
614 if (ctx->errno)
615 UCI_THROW(ctx, ctx->errno);
616 if (err)
617 UCI_THROW(ctx, UCI_ERR_IO);
618 return 0;
619 }
620
621
622 /*
623 * This function returns the filename by returning the string
624 * after the last '/' character. By checking for a non-'\0'
625 * character afterwards, directories are ignored (glob marks
626 * those with a trailing '/'
627 */
628 static inline char *get_filename(char *path)
629 {
630 char *p;
631
632 p = strrchr(path, '/');
633 p++;
634 if (!*p)
635 return NULL;
636 return p;
637 }
638
639 char **uci_list_configs(struct uci_context *ctx)
640 {
641 char **configs;
642 glob_t globbuf;
643 int size, i;
644 char *buf;
645
646 if (glob(UCI_CONFDIR "/*", GLOB_MARK, NULL, &globbuf) != 0)
647 return NULL;
648
649 size = sizeof(char *) * (globbuf.gl_pathc + 1);
650 for(i = 0; i < globbuf.gl_pathc; i++) {
651 char *p;
652
653 p = get_filename(globbuf.gl_pathv[i]);
654 if (!p)
655 continue;
656
657 size += strlen(p) + 1;
658 }
659
660 configs = malloc(size);
661 if (!configs)
662 return NULL;
663
664 memset(configs, 0, size);
665 buf = (char *) &configs[globbuf.gl_pathc + 1];
666 for(i = 0; i < globbuf.gl_pathc; i++) {
667 char *p;
668
669 p = get_filename(globbuf.gl_pathv[i]);
670 if (!p)
671 continue;
672
673 configs[i] = buf;
674 strcpy(buf, p);
675 buf += strlen(buf) + 1;
676 }
677 return configs;
678 }
679
680