extend uci_set so that it can store the resulting element in a variable
[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 #define _GNU_SOURCE
20 #include <sys/types.h>
21 #include <sys/file.h>
22 #include <stdbool.h>
23 #include <unistd.h>
24 #include <fcntl.h>
25 #include <stdio.h>
26 #include <ctype.h>
27
28 /*
29 * Clean up all extra memory used by the parser and exporter
30 */
31 static void uci_file_cleanup(struct uci_context *ctx)
32 {
33 struct uci_parse_context *pctx;
34
35 if (ctx->buf) {
36 free(ctx->buf);
37 ctx->buf = NULL;
38 ctx->bufsz = 0;
39 }
40
41 pctx = ctx->pctx;
42 if (!pctx)
43 return;
44
45 ctx->pctx = NULL;
46 if (pctx->package)
47 uci_free_package(&pctx->package);
48
49 if (pctx->buf)
50 free(pctx->buf);
51
52 free(pctx);
53 }
54
55
56 /*
57 * verify that the end of the line or command is reached.
58 * throw an error if extra arguments are given on the command line
59 */
60 static void assert_eol(struct uci_context *ctx, char **str)
61 {
62 char *tmp;
63
64 tmp = next_arg(ctx, str, false, false);
65 if (*tmp && (ctx->flags & UCI_FLAG_STRICT))
66 uci_parse_error(ctx, *str, "too many arguments");
67 }
68
69 /*
70 * switch to a different config, either triggered by uci_load, or by a
71 * 'package <...>' statement in the import file
72 */
73 static void uci_switch_config(struct uci_context *ctx)
74 {
75 struct uci_parse_context *pctx;
76 struct uci_element *e;
77 const char *name;
78
79 pctx = ctx->pctx;
80 name = pctx->name;
81
82 /* add the last config to main config file list */
83 if (pctx->package) {
84 uci_list_add(&ctx->root, &pctx->package->e.list);
85
86 pctx->package = NULL;
87 pctx->section = NULL;
88 }
89
90 if (!name)
91 return;
92
93 /*
94 * if an older config under the same name exists, unload it
95 * ignore errors here, e.g. if the config was not found
96 */
97 e = uci_lookup_list(ctx, &ctx->root, name);
98 if (e)
99 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
100 pctx->package = uci_alloc_package(ctx, name);
101 }
102
103 /*
104 * parse the 'package' uci command (next config package)
105 */
106 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
107 {
108 char *name = NULL;
109
110 /* command string null-terminated by strtok */
111 *str += strlen(*str) + 1;
112
113 name = next_arg(ctx, str, true, true);
114 assert_eol(ctx, str);
115 if (single)
116 return;
117
118 ctx->pctx->name = name;
119 uci_switch_config(ctx);
120 }
121
122 /* Based on an efficient hash function published by D. J. Bernstein */
123 static unsigned int djbhash(unsigned int hash, char *str)
124 {
125 int len = strlen(str);
126 int i;
127
128 /* initial value */
129 if (hash == ~0)
130 hash = 5381;
131
132 for(i = 0; i < len; i++) {
133 hash = ((hash << 5) + hash) + str[i];
134 }
135 return (hash & 0x7FFFFFFF);
136 }
137
138 /* fix up an unnamed section */
139 static void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
140 {
141 unsigned int hash = ~0;
142 struct uci_element *e;
143 char buf[16];
144
145 if (!s || s->e.name)
146 return;
147
148 /*
149 * Generate a name for unnamed sections. This is used as reference
150 * when locating or updating the section from apps/scripts.
151 * To make multiple concurrent versions somewhat safe for updating,
152 * the name is generated from a hash of its type and name/value
153 * pairs of its option, and it is prefixed by a counter value.
154 * If the order of the unnamed sections changes for some reason,
155 * updates to them will be rejected.
156 */
157 hash = djbhash(hash, s->type);
158 uci_foreach_element(&s->options, e) {
159 hash = djbhash(hash, e->name);
160 hash = djbhash(hash, uci_to_option(e)->value);
161 }
162 sprintf(buf, "cfg%02x%04x", ++s->package->n_section, hash % (1 << 16));
163 s->e.name = uci_strdup(ctx, buf);
164 }
165
166 /*
167 * parse the 'config' uci command (open a section)
168 */
169 static void uci_parse_config(struct uci_context *ctx, char **str)
170 {
171 struct uci_parse_context *pctx = ctx->pctx;
172 char *name = NULL;
173 char *type = NULL;
174
175 uci_fixup_section(ctx, ctx->pctx->section);
176 if (!ctx->pctx->package) {
177 if (!ctx->pctx->name)
178 uci_parse_error(ctx, *str, "attempting to import a file without a package name");
179
180 uci_switch_config(ctx);
181 }
182
183 /* command string null-terminated by strtok */
184 *str += strlen(*str) + 1;
185
186 type = next_arg(ctx, str, true, false);
187 if (!uci_validate_str(type, false))
188 uci_parse_error(ctx, type, "invalid character in field");
189 name = next_arg(ctx, str, false, true);
190 assert_eol(ctx, str);
191
192 if (pctx->merge) {
193 UCI_TRAP_SAVE(ctx, error);
194 uci_set(ctx, pctx->package, name, NULL, type, NULL);
195 UCI_TRAP_RESTORE(ctx);
196 return;
197 error:
198 UCI_THROW(ctx, ctx->errno);
199 } else
200 pctx->section = uci_alloc_section(pctx->package, type, name);
201 }
202
203 /*
204 * parse the 'option' uci command (open a value)
205 */
206 static void uci_parse_option(struct uci_context *ctx, char **str)
207 {
208 struct uci_parse_context *pctx = ctx->pctx;
209 char *name = NULL;
210 char *value = NULL;
211
212 if (!pctx->section)
213 uci_parse_error(ctx, *str, "option command found before the first section");
214
215 /* command string null-terminated by strtok */
216 *str += strlen(*str) + 1;
217
218 name = next_arg(ctx, str, true, true);
219 value = next_arg(ctx, str, false, false);
220 assert_eol(ctx, str);
221
222 if (pctx->merge) {
223 UCI_TRAP_SAVE(ctx, error);
224 uci_set(ctx, pctx->package, pctx->section->e.name, name, value, NULL);
225 UCI_TRAP_RESTORE(ctx);
226 return;
227 error:
228 UCI_THROW(ctx, ctx->errno);
229 } else
230 uci_alloc_option(pctx->section, name, value);
231 }
232
233
234 /*
235 * parse a complete input line, split up combined commands by ';'
236 */
237 static void uci_parse_line(struct uci_context *ctx, bool single)
238 {
239 struct uci_parse_context *pctx = ctx->pctx;
240 char *word, *brk = NULL;
241
242 for (word = strtok_r(pctx->buf, ";", &brk);
243 word;
244 word = strtok_r(NULL, ";", &brk)) {
245
246 char *pbrk = NULL;
247 word = strtok_r(word, " \t", &pbrk);
248
249 if (!word)
250 continue;
251
252 switch(word[0]) {
253 case '#':
254 return;
255 case 'p':
256 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
257 uci_parse_package(ctx, &word, single);
258 break;
259 case 'c':
260 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
261 uci_parse_config(ctx, &word);
262 break;
263 case 'o':
264 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
265 uci_parse_option(ctx, &word);
266 break;
267 default:
268 uci_parse_error(ctx, word, "unterminated command");
269 break;
270 }
271 }
272 }
273
274 /* max number of characters that escaping adds to the string */
275 #define UCI_QUOTE_ESCAPE "'\\''"
276
277 /*
278 * escape an uci string for export
279 */
280 static char *uci_escape(struct uci_context *ctx, char *str)
281 {
282 char *s, *p;
283 int pos = 0;
284
285 if (!ctx->buf) {
286 ctx->bufsz = LINEBUF;
287 ctx->buf = malloc(LINEBUF);
288 }
289
290 s = str;
291 p = strchr(str, '\'');
292 if (!p)
293 return str;
294
295 do {
296 int len = p - s;
297 if (len > 0) {
298 if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
299 ctx->bufsz *= 2;
300 ctx->buf = realloc(ctx->buf, ctx->bufsz);
301 if (!ctx->buf)
302 UCI_THROW(ctx, UCI_ERR_MEM);
303 }
304 memcpy(&ctx->buf[pos], s, len);
305 pos += len;
306 }
307 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
308 pos += sizeof(UCI_QUOTE_ESCAPE);
309 s = p + 1;
310 } while ((p = strchr(s, '\'')));
311
312 return ctx->buf;
313 }
314
315
316 /*
317 * export a single config package to a file stream
318 */
319 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
320 {
321 struct uci_context *ctx = p->ctx;
322 struct uci_element *s, *o;
323
324 if (header)
325 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
326 uci_foreach_element(&p->sections, s) {
327 struct uci_section *sec = uci_to_section(s);
328 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
329 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
330 fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
331 fprintf(stream, "\n");
332 uci_foreach_element(&sec->options, o) {
333 struct uci_option *opt = uci_to_option(o);
334 fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
335 fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
336 }
337 }
338 fprintf(stream, "\n");
339 }
340
341 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
342 {
343 struct uci_element *e;
344
345 UCI_HANDLE_ERR(ctx);
346 UCI_ASSERT(ctx, stream != NULL);
347
348 if (package)
349 uci_export_package(package, stream, header);
350 else {
351 uci_foreach_element(&ctx->root, e) {
352 uci_export_package(uci_to_package(e), stream, header);
353 }
354 }
355
356 return 0;
357 }
358
359 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
360 {
361 struct uci_parse_context *pctx;
362 UCI_HANDLE_ERR(ctx);
363
364 /* make sure no memory from previous parse attempts is leaked */
365 uci_file_cleanup(ctx);
366
367 uci_alloc_parse_context(ctx);
368 pctx = ctx->pctx;
369 pctx->file = stream;
370 if (*package && single) {
371 pctx->package = *package;
372 pctx->merge = true;
373 }
374
375 /*
376 * If 'name' was supplied, assume that the supplied stream does not contain
377 * the appropriate 'package <name>' string to specify the config name
378 * NB: the config file can still override the package name
379 */
380 if (name) {
381 UCI_ASSERT(ctx, uci_validate_name(name));
382 pctx->name = name;
383 }
384
385 while (!feof(pctx->file)) {
386 uci_getln(ctx, 0);
387 UCI_TRAP_SAVE(ctx, error);
388 if (pctx->buf[0])
389 uci_parse_line(ctx, single);
390 UCI_TRAP_RESTORE(ctx);
391 continue;
392 error:
393 if (ctx->flags & UCI_FLAG_PERROR)
394 uci_perror(ctx, NULL);
395 if ((ctx->errno != UCI_ERR_PARSE) ||
396 (ctx->flags & UCI_FLAG_STRICT))
397 UCI_THROW(ctx, ctx->errno);
398 }
399
400 uci_fixup_section(ctx, ctx->pctx->section);
401 if (package)
402 *package = pctx->package;
403 if (pctx->merge)
404 pctx->package = NULL;
405
406 pctx->name = NULL;
407 uci_switch_config(ctx);
408
409 /* no error happened, we can get rid of the parser context now */
410 uci_file_cleanup(ctx);
411
412 return 0;
413 }
414
415
416 static char *uci_config_path(struct uci_context *ctx, const char *name)
417 {
418 char *filename;
419
420 UCI_ASSERT(ctx, uci_validate_name(name));
421 filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
422 sprintf(filename, "%s/%s", ctx->confdir, name);
423
424 return filename;
425 }
426
427 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
428 {
429 char *filename;
430 bool confdir;
431 FILE *file = NULL;
432
433 UCI_HANDLE_ERR(ctx);
434
435 switch (name[0]) {
436 case '.':
437 /* relative path outside of /etc/config */
438 if (name[1] != '/')
439 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
440 /* fall through */
441 case '/':
442 /* absolute path outside of /etc/config */
443 filename = uci_strdup(ctx, name);
444 name = strrchr(name, '/') + 1;
445 confdir = false;
446 break;
447 default:
448 /* config in /etc/config */
449 filename = uci_config_path(ctx, name);
450 confdir = true;
451 break;
452 }
453
454 file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
455 ctx->errno = 0;
456 UCI_TRAP_SAVE(ctx, done);
457 UCI_INTERNAL(uci_import, ctx, file, name, package, true);
458 UCI_TRAP_RESTORE(ctx);
459
460 if (*package) {
461 (*package)->path = filename;
462 (*package)->confdir = confdir;
463 uci_load_history(ctx, *package, false);
464 }
465
466 done:
467 uci_close_stream(file);
468 return ctx->errno;
469 }
470
471 int uci_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
472 {
473 struct uci_package *p;
474 FILE *f = NULL;
475 char *name = NULL;
476 char *path = NULL;
477
478 UCI_HANDLE_ERR(ctx);
479 UCI_ASSERT(ctx, package != NULL);
480 p = *package;
481
482 UCI_ASSERT(ctx, p != NULL);
483 if (!p->path) {
484 if (overwrite)
485 p->path = uci_config_path(ctx, p->e.name);
486 else
487 UCI_THROW(ctx, UCI_ERR_INVAL);
488 }
489
490
491 /* open the config file for writing now, so that it is locked */
492 f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
493
494 /* flush unsaved changes and reload from history file */
495 UCI_TRAP_SAVE(ctx, done);
496 if (p->confdir) {
497 if (!overwrite) {
498 name = uci_strdup(ctx, p->e.name);
499 path = uci_strdup(ctx, p->path);
500 /* dump our own changes to the history file */
501 if (!uci_list_empty(&p->history))
502 UCI_INTERNAL(uci_save, ctx, p);
503
504 /*
505 * other processes might have modified the config
506 * as well. dump and reload
507 */
508 uci_free_package(&p);
509 uci_file_cleanup(ctx);
510 UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
511
512 p->path = path;
513 p->confdir = true;
514 *package = p;
515
516 /* freed together with the uci_package */
517 path = NULL;
518
519 /* check for updated history, flush */
520 if (!uci_load_history(ctx, p, true))
521 goto done;
522 } else {
523 /* flush history */
524 if (!uci_load_history(ctx, NULL, true))
525 goto done;
526 }
527 }
528
529 rewind(f);
530 ftruncate(fileno(f), 0);
531
532 uci_export(ctx, f, p, false);
533 UCI_TRAP_RESTORE(ctx);
534
535 done:
536 if (name)
537 free(name);
538 if (path)
539 free(path);
540 uci_close_stream(f);
541 if (ctx->errno)
542 UCI_THROW(ctx, ctx->errno);
543
544 return 0;
545 }
546
547
548 /*
549 * This function returns the filename by returning the string
550 * after the last '/' character. By checking for a non-'\0'
551 * character afterwards, directories are ignored (glob marks
552 * those with a trailing '/'
553 */
554 static inline char *get_filename(char *path)
555 {
556 char *p;
557
558 p = strrchr(path, '/');
559 p++;
560 if (!*p)
561 return NULL;
562 return p;
563 }
564
565 int uci_list_configs(struct uci_context *ctx, char ***list)
566 {
567 char **configs;
568 glob_t globbuf;
569 int size, i;
570 char *buf;
571 char *dir;
572
573 UCI_HANDLE_ERR(ctx);
574
575 dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
576 sprintf(dir, "%s/*", ctx->confdir);
577 if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
578 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
579
580 size = sizeof(char *) * (globbuf.gl_pathc + 1);
581 for(i = 0; i < globbuf.gl_pathc; i++) {
582 char *p;
583
584 p = get_filename(globbuf.gl_pathv[i]);
585 if (!p)
586 continue;
587
588 size += strlen(p) + 1;
589 }
590
591 configs = uci_malloc(ctx, size);
592 buf = (char *) &configs[globbuf.gl_pathc + 1];
593 for(i = 0; i < globbuf.gl_pathc; i++) {
594 char *p;
595
596 p = get_filename(globbuf.gl_pathv[i]);
597 if (!p)
598 continue;
599
600 configs[i] = buf;
601 strcpy(buf, p);
602 buf += strlen(buf) + 1;
603 }
604 *list = configs;
605 free(dir);
606
607 return 0;
608 }
609