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Sources/uci/uci.h

  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 #ifndef __LIBUCI_H
 16 #define __LIBUCI_H
 17 
 18 #ifdef __cplusplus
 19 extern "C" {
 20 #endif
 21 
 22 #include "uci_config.h"
 23 
 24 /*
 25  * you can use these defines to enable debugging behavior for
 26  * apps compiled against libuci:
 27  *
 28  * #define UCI_DEBUG_TYPECAST:
 29  *   enable uci_element typecast checking at run time
 30  *
 31  */
 32 
 33 #include <stdbool.h>
 34 #include <setjmp.h>
 35 #include <stdio.h>
 36 #include <stdint.h>
 37 #include <stddef.h>
 38 
 39 #define UCI_CONFDIR "/etc/config"
 40 #define UCI_SAVEDIR "/tmp/.uci"
 41 #define UCI_DIRMODE 0700
 42 #define UCI_FILEMODE 0600
 43 
 44 enum
 45 {
 46         UCI_OK = 0,
 47         UCI_ERR_MEM,
 48         UCI_ERR_INVAL,
 49         UCI_ERR_NOTFOUND,
 50         UCI_ERR_IO,
 51         UCI_ERR_PARSE,
 52         UCI_ERR_DUPLICATE,
 53         UCI_ERR_UNKNOWN,
 54         UCI_ERR_LAST
 55 };
 56 
 57 struct uci_list;
 58 struct uci_list
 59 {
 60         struct uci_list *next;
 61         struct uci_list *prev;
 62 };
 63 
 64 struct uci_ptr;
 65 struct uci_element;
 66 struct uci_package;
 67 struct uci_section;
 68 struct uci_option;
 69 struct uci_delta;
 70 struct uci_context;
 71 struct uci_backend;
 72 struct uci_parse_option;
 73 struct uci_parse_context;
 74 
 75 
 76 /**
 77  * uci_alloc_context: Allocate a new uci context
 78  */
 79 extern struct uci_context *uci_alloc_context(void);
 80 
 81 /**
 82  * uci_free_context: Free the uci context including all of its data
 83  */
 84 extern void uci_free_context(struct uci_context *ctx);
 85 
 86 /**
 87  * uci_perror: Print the last uci error that occured
 88  * @ctx: uci context
 89  * @str: string to print before the error message
 90  */
 91 extern void uci_perror(struct uci_context *ctx, const char *str);
 92 
 93 /**
 94  * uci_geterror: Get an error string for the last uci error
 95  * @ctx: uci context
 96  * @dest: target pointer for the string
 97  * @str: prefix for the error message
 98  *
 99  * Note: string must be freed by the caller
100  */
101 extern void uci_get_errorstr(struct uci_context *ctx, char **dest, const char *str);
102 
103 /**
104  * uci_import: Import uci config data from a stream
105  * @ctx: uci context
106  * @stream: file stream to import from
107  * @name: (optional) assume the config has the given name
108  * @package: (optional) store the last parsed config package in this variable
109  * @single: ignore the 'package' keyword and parse everything into a single package
110  *
111  * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
112  * if 'package' points to a non-null struct pointer, enable delta tracking and merge
113  */
114 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
115 
116 /**
117  * uci_export: Export one or all uci config packages
118  * @ctx: uci context
119  * @stream: output stream
120  * @package: (optional) uci config package to export
121  * @header: include the package header
122  */
123 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
124 
125 /**
126  * uci_load: Parse an uci config file and store it in the uci context
127  *
128  * @ctx: uci context
129  * @name: name of the config file (relative to the config directory)
130  * @package: store the loaded config package in this variable
131  */
132 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
133 
134 /**
135  * uci_unload: Unload a config file from the uci context
136  *
137  * @ctx: uci context
138  * @package: pointer to the uci_package struct
139  */
140 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
141 
142 /**
143  * uci_lookup_ptr: Split an uci tuple string and look up an element tree
144  * @ctx: uci context
145  * @ptr: lookup result struct
146  * @str: uci tuple string to look up
147  * @extended: allow extended syntax lookup
148  *
149  * if extended is set to true, uci_lookup_ptr supports the following
150  * extended syntax:
151  *
152  * Examples:
153  *   network.@interface[0].ifname ('ifname' option of the first interface section)
154  *   network.@interface[-1]       (last interface section)
155  * Note: uci_lookup_ptr will automatically load a config package if necessary
156  * @str must not be constant, as it will be modified and used for the strings inside @ptr,
157  * thus it must also be available as long as @ptr is in use.
158  *
159  * This function returns UCI_ERR_NOTFOUND if the package specified in the tuple
160  * string cannot be found.  Otherwise it will return UCI_OK.
161  *
162  * Note that failures in looking up other parts, if they are also specfied,
163  * including section and option, will also have a return value UCI_OK but with
164  * ptr->flags * UCI_LOOKUP_COMPLETE not set.
165  */
166 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
167 
168 /**
169  * uci_add_section: Add an unnamed section
170  * @ctx: uci context
171  * @p: package to add the section to
172  * @type: section type
173  * @res: pointer to store a reference to the new section in
174  */
175 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
176 
177 /**
178  * uci_set: Set an element's value; create the element if necessary
179  * @ctx: uci context
180  * @ptr: uci pointer
181  *
182  * The updated/created element is stored in ptr->last
183  */
184 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
185 
186 /**
187  * uci_add_list: Append a string to an element list
188  * @ctx: uci context
189  * @ptr: uci pointer (with value)
190  *
191  * Note: if the given option already contains a string value,
192  * it will be converted to an 1-element-list before appending the next element
193  */
194 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
195 
196 /**
197  * uci_del_list: Remove a string from an element list
198  * @ctx: uci context
199  * @ptr: uci pointer (with value)
200  *
201  */
202 extern int uci_del_list(struct uci_context *ctx, struct uci_ptr *ptr);
203 
204 /**
205  * uci_reorder: Reposition a section
206  * @ctx: uci context
207  * @s: uci section to reposition
208  * @pos: new position in the section list
209  */
210 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
211 
212 /**
213  * uci_rename: Rename an element
214  * @ctx: uci context
215  * @ptr: uci pointer (with value)
216  */
217 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
218 
219 /**
220  * uci_delete: Delete a section or option
221  * @ctx: uci context
222  * @ptr: uci pointer
223  */
224 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
225 
226 /**
227  * uci_save: save change delta for a package
228  * @ctx: uci context
229  * @p: uci_package struct
230  */
231 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
232 
233 /**
234  * uci_commit: commit changes to a package
235  * @ctx: uci context
236  * @p: uci_package struct pointer
237  * @overwrite: overwrite existing config data and flush delta
238  *
239  * committing may reload the whole uci_package data,
240  * the supplied pointer is updated accordingly
241  */
242 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
243 
244 /**
245  * uci_list_configs: List available uci config files
246  * @ctx: uci context
247  *
248  * caller is responsible for freeing the allocated memory behind list
249  */
250 extern int uci_list_configs(struct uci_context *ctx, char ***list);
251 
252 /**
253  * uci_set_savedir: override the default delta save directory
254  * @ctx: uci context
255  * @dir: directory name
256  *
257  * This will also try adding the specified dir to the end of delta pathes.
258  */
259 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
260 
261 /**
262  * uci_set_savedir: override the default config storage directory
263  * @ctx: uci context
264  * @dir: directory name
265  */
266 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
267 
268 /**
269  * uci_add_delta_path: add a directory to the search path for change delta files
270  * @ctx: uci context
271  * @dir: directory name
272  *
273  * This function allows you to add directories, which contain 'overlays'
274  * for the active config, that will never be committed.
275  *
276  * Adding a duplicate directory will cause UCI_ERR_DUPLICATE be returned.
277  */
278 extern int uci_add_delta_path(struct uci_context *ctx, const char *dir);
279 
280 /**
281  * uci_revert: revert all changes to a config item
282  * @ctx: uci context
283  * @ptr: uci pointer
284  */
285 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
286 
287 /**
288  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
289  * @ctx: uci context
290  * @stream: input stream
291  * @str: pointer to the current line (use NULL for parsing the next line)
292  * @result: pointer for the result
293  */
294 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
295 
296 /**
297  * uci_set_backend: change the default backend
298  * @ctx: uci context
299  * @name: name of the backend
300  *
301  * The default backend is "file", which uses /etc/config for config storage
302  */
303 extern int uci_set_backend(struct uci_context *ctx, const char *name);
304 
305 /**
306  * uci_validate_text: validate a value string for uci options
307  * @str: value
308  *
309  * this function checks whether a given string is acceptable as value
310  * for uci options
311  */
312 extern bool uci_validate_text(const char *str);
313 
314 /**
315  * uci_parse_ptr: parse a uci string into a uci_ptr
316  * @ctx: uci context
317  * @ptr: target data structure
318  * @str: string to parse
319  *
320  * str is modified by this function
321  */
322 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str);
323 
324 /**
325  * uci_lookup_next: lookup a child element
326  * @ctx: uci context
327  * @e: target element pointer
328  * @list: list of elements
329  * @name: name of the child element
330  *
331  * if parent is NULL, the function looks up the package with the given name
332  */
333 int uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name);
334 
335 /**
336  * uci_parse_section: look up a set of options
337  * @s: uci section
338  * @opts: list of options to look up
339  * @n_opts: number of options to look up
340  * @tb: array of pointers to found options
341  */
342 void uci_parse_section(struct uci_section *s, const struct uci_parse_option *opts,
343                        int n_opts, struct uci_option **tb);
344 
345 /**
346  * uci_hash_options: build a hash over a list of options
347  * @tb: list of option pointers
348  * @n_opts: number of options
349  */
350 uint32_t uci_hash_options(struct uci_option **tb, int n_opts);
351 
352 
353 /* UCI data structures */
354 enum uci_type {
355         UCI_TYPE_UNSPEC = 0,
356         UCI_TYPE_DELTA = 1,
357         UCI_TYPE_PACKAGE = 2,
358         UCI_TYPE_SECTION = 3,
359         UCI_TYPE_OPTION = 4,
360         UCI_TYPE_PATH = 5,
361         UCI_TYPE_BACKEND = 6,
362         UCI_TYPE_ITEM = 7,
363         UCI_TYPE_HOOK = 8,
364 };
365 
366 enum uci_option_type {
367         UCI_TYPE_STRING = 0,
368         UCI_TYPE_LIST = 1,
369 };
370 
371 enum uci_flags {
372         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
373         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
374         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
375         UCI_FLAG_SAVED_DELTA = (1 << 3), /* store the saved delta in memory as well */
376 };
377 
378 struct uci_element
379 {
380         struct uci_list list;
381         enum uci_type type;
382         char *name;
383 };
384 
385 struct uci_backend
386 {
387         struct uci_element e;
388         char **(*list_configs)(struct uci_context *ctx);
389         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
390         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
391 
392         /* private: */
393         const void *ptr;
394         void *priv;
395 };
396 
397 struct uci_context
398 {
399         /* list of config packages */
400         struct uci_list root;
401 
402         /* parser context, use for error handling only */
403         struct uci_parse_context *pctx;
404 
405         /* backend for import and export */
406         struct uci_backend *backend;
407         struct uci_list backends;
408 
409         /* uci runtime flags */
410         enum uci_flags flags;
411 
412         char *confdir;
413         char *savedir;
414 
415         /* search path for delta files */
416         struct uci_list delta_path;
417 
418         /* private: */
419         int err;
420         const char *func;
421         jmp_buf trap;
422         bool internal, nested;
423         char *buf;
424         int bufsz;
425 };
426 
427 struct uci_package
428 {
429         struct uci_element e;
430         struct uci_list sections;
431         struct uci_context *ctx;
432         bool has_delta;
433         char *path;
434 
435         /* private: */
436         struct uci_backend *backend;
437         void *priv;
438         int n_section;
439         struct uci_list delta;
440         struct uci_list saved_delta;
441 };
442 
443 struct uci_section
444 {
445         struct uci_element e;
446         struct uci_list options;
447         struct uci_package *package;
448         bool anonymous;
449         char *type;
450 };
451 
452 struct uci_option
453 {
454         struct uci_element e;
455         struct uci_section *section;
456         enum uci_option_type type;
457         union {
458                 struct uci_list list;
459                 char *string;
460         } v;
461 };
462 
463 /*
464  * UCI_CMD_ADD is used for anonymous sections or list values
465  */
466 enum uci_command {
467         UCI_CMD_ADD,
468         UCI_CMD_REMOVE,
469         UCI_CMD_CHANGE,
470         UCI_CMD_RENAME,
471         UCI_CMD_REORDER,
472         UCI_CMD_LIST_ADD,
473         UCI_CMD_LIST_DEL,
474         __UCI_CMD_MAX,
475         __UCI_CMD_LAST = __UCI_CMD_MAX - 1
476 };
477 extern char const uci_command_char[];
478 
479 struct uci_delta
480 {
481         struct uci_element e;
482         enum uci_command cmd;
483         char *section;
484         char *value;
485 };
486 
487 struct uci_ptr
488 {
489         enum uci_type target;
490         enum {
491                 UCI_LOOKUP_DONE =     (1 << 0),
492                 UCI_LOOKUP_COMPLETE = (1 << 1),
493                 UCI_LOOKUP_EXTENDED = (1 << 2),
494         } flags;
495 
496         struct uci_package *p;
497         struct uci_section *s;
498         struct uci_option *o;
499         struct uci_element *last;
500 
501         const char *package;
502         const char *section;
503         const char *option;
504         const char *value;
505 };
506 
507 struct uci_parse_option {
508         const char *name;
509         enum uci_option_type type;
510 };
511 
512 
513 /**
514  * container_of - cast a member of a structure out to the containing structure
515  * @ptr:    the pointer to the member.
516  * @type:   the type of the container struct this is embedded in.
517  * @member: the name of the member within the struct.
518  */
519 #ifndef container_of
520 #define container_of(ptr, type, member) \
521         ((type *) ((char *)ptr - offsetof(type,member)))
522 #endif
523 
524 
525 /**
526  * uci_list_entry: casts an uci_list pointer to the containing struct.
527  * @_type: config, section or option
528  * @_ptr: pointer to the uci_list struct
529  */
530 #define list_to_element(ptr) \
531         container_of(ptr, struct uci_element, list)
532 
533 /**
534  * uci_foreach_entry: loop through a list of uci elements
535  * @_list: pointer to the uci_list struct
536  * @_ptr: iteration variable, struct uci_element
537  *
538  * use like a for loop, e.g:
539  *   uci_foreach(&list, p) {
540  *      ...
541  *   }
542  */
543 #define uci_foreach_element(_list, _ptr)                \
544         for(_ptr = list_to_element((_list)->next);      \
545                 &_ptr->list != (_list);                 \
546                 _ptr = list_to_element(_ptr->list.next))
547 
548 /**
549  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
550  * @_list: pointer to the uci_list struct
551  * @_tmp: temporary variable, struct uci_element *
552  * @_ptr: iteration variable, struct uci_element *
553  *
554  * use like a for loop, e.g:
555  *   uci_foreach(&list, p) {
556  *      ...
557  *   }
558  */
559 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
560         for(_ptr = list_to_element((_list)->next),              \
561                 _tmp = list_to_element(_ptr->list.next);        \
562                 &_ptr->list != (_list);                 \
563                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
564 
565 /**
566  * uci_list_empty: returns true if a list is empty
567  * @list: list head
568  */
569 #define uci_list_empty(list) ((list)->next == (list))
570 
571 /* wrappers for dynamic type handling */
572 #define uci_type_backend UCI_TYPE_BACKEND
573 #define uci_type_delta UCI_TYPE_DELTA
574 #define uci_type_package UCI_TYPE_PACKAGE
575 #define uci_type_section UCI_TYPE_SECTION
576 #define uci_type_option UCI_TYPE_OPTION
577 
578 /* element typecasting */
579 #ifdef UCI_DEBUG_TYPECAST
580 static const char *uci_typestr[] = {
581         [uci_type_backend] = "backend",
582         [uci_type_delta] = "delta",
583         [uci_type_package] = "package",
584         [uci_type_section] = "section",
585         [uci_type_option] = "option",
586 };
587 
588 static void uci_typecast_error(int from, int to)
589 {
590         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
591 }
592 
593 #define BUILD_CAST(_type) \
594         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
595         { \
596                 if (e->type != uci_type_ ## _type) { \
597                         uci_typecast_error(e->type, uci_type_ ## _type); \
598                 } \
599                 return (struct uci_ ## _type *) e; \
600         }
601 
602 BUILD_CAST(backend)
603 BUILD_CAST(delta)
604 BUILD_CAST(package)
605 BUILD_CAST(section)
606 BUILD_CAST(option)
607 
608 #else
609 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
610 #define uci_to_delta(ptr) container_of(ptr, struct uci_delta, e)
611 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
612 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
613 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
614 #endif
615 
616 /**
617  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
618  * @ctx: uci context
619  * @type: {package,section,option}
620  * @name: string containing the name of the element
621  * @datasize: additional buffer size to reserve at the end of the struct
622  */
623 #define uci_alloc_element(ctx, type, name, datasize) \
624         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
625 
626 #define uci_dataptr(ptr) \
627         (((char *) ptr) + sizeof(*ptr))
628 
629 /**
630  * uci_lookup_package: look up a package
631  * @ctx: uci context
632  * @name: name of the package
633  */
634 static inline struct uci_package *
635 uci_lookup_package(struct uci_context *ctx, const char *name)
636 {
637         struct uci_element *e = NULL;
638         if (uci_lookup_next(ctx, &e, &ctx->root, name) == 0)
639                 return uci_to_package(e);
640         else
641                 return NULL;
642 }
643 
644 /**
645  * uci_lookup_section: look up a section
646  * @ctx: uci context
647  * @p: package that the section belongs to
648  * @name: name of the section
649  */
650 static inline struct uci_section *
651 uci_lookup_section(struct uci_context *ctx, struct uci_package *p, const char *name)
652 {
653         struct uci_element *e = NULL;
654         if (uci_lookup_next(ctx, &e, &p->sections, name) == 0)
655                 return uci_to_section(e);
656         else
657                 return NULL;
658 }
659 
660 /**
661  * uci_lookup_option: look up an option
662  * @ctx: uci context
663  * @section: section that the option belongs to
664  * @name: name of the option
665  */
666 static inline struct uci_option *
667 uci_lookup_option(struct uci_context *ctx, struct uci_section *s, const char *name)
668 {
669         struct uci_element *e = NULL;
670         if (uci_lookup_next(ctx, &e, &s->options, name) == 0)
671                 return uci_to_option(e);
672         else
673                 return NULL;
674 }
675 
676 static inline const char *
677 uci_lookup_option_string(struct uci_context *ctx, struct uci_section *s, const char *name)
678 {
679         struct uci_option *o;
680 
681         o = uci_lookup_option(ctx, s, name);
682         if (!o || o->type != UCI_TYPE_STRING)
683                 return NULL;
684 
685         return o->v.string;
686 }
687 
688 #ifndef BITS_PER_LONG
689 #define BITS_PER_LONG (8 * sizeof(unsigned long))
690 #endif
691 
692 static inline void uci_bitfield_set(unsigned long *bits, int bit)
693 {
694         bits[bit / BITS_PER_LONG] |= (1UL << (bit % BITS_PER_LONG));
695 }
696 
697 #ifdef __cplusplus
698 }
699 #endif
700 
701 #endif
702 

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