2 * UCW Library -- Configuration files
4 * (c) 2001--2006 Robert Spalek <robert@ucw.cz>
5 * (c) 2003--2014 Martin Mares <mj@ucw.cz>
7 * This software may be freely distributed and used according to the terms
8 * of the GNU Lesser General Public License.
14 #include <ucw/clists.h>
17 #ifdef CONFIG_UCW_CLEAN_ABI
18 #define cf_close_group ucw_cf_close_group
19 #define cf_declare_rel_section ucw_cf_declare_rel_section
20 #define cf_declare_section ucw_cf_declare_section
21 #define cf_delete_context ucw_cf_delete_context
22 #define cf_dump_sections ucw_cf_dump_sections
23 #define cf_find_item ucw_cf_find_item
24 #define cf_get_pool ucw_cf_get_pool
25 #define cf_init_section ucw_cf_init_section
26 #define cf_journal_block ucw_cf_journal_block
27 #define cf_journal_commit_transaction ucw_cf_journal_commit_transaction
28 #define cf_journal_new_transaction ucw_cf_journal_new_transaction
29 #define cf_journal_rollback_transaction ucw_cf_journal_rollback_transaction
30 #define cf_load ucw_cf_load
31 #define cf_malloc ucw_cf_malloc
32 #define cf_malloc_zero ucw_cf_malloc_zero
33 #define cf_modify_item ucw_cf_modify_item
34 #define cf_new_context ucw_cf_new_context
35 #define cf_open_group ucw_cf_open_group
36 #define cf_parse_double ucw_cf_parse_double
37 #define cf_parse_int ucw_cf_parse_int
38 #define cf_parse_ip ucw_cf_parse_ip
39 #define cf_parse_u64 ucw_cf_parse_u64
40 #define cf_printf ucw_cf_printf
41 #define cf_reload ucw_cf_reload
42 #define cf_revert ucw_cf_revert
43 #define cf_set ucw_cf_set
44 #define cf_set_journalling ucw_cf_set_journalling
45 #define cf_strdup ucw_cf_strdup
46 #define cf_switch_context ucw_cf_switch_context
53 * Configuration contexts
54 * ~~~~~~~~~~~~~~~~~~~~~~
56 * The state of the configuration parser is stored within a configuration context.
57 * One such context is automatically created during initialization of the library
58 * and you need not care about more, as long as you use a single configuration file.
60 * In full generality, you can define as many contexts as you wish and switch
61 * between them. Each thread has its own pointer to the current context, which
62 * must not be shared with other threads.
65 /** Create a new configuration context. **/
66 struct cf_context *cf_new_context(void);
69 * Free a configuration context. The context must not be set as current
70 * for any thread, nor can it be the default context.
72 * All configuration settings made within the context are rolled back
73 * (except when journalling is turned off). All memory allocated on behalf
74 * of the context is freed, which includes memory obtained by calls to
77 void cf_delete_context(struct cf_context *cc);
80 * Make the given configuration context current and return the previously
81 * active context. Both the new and the old context may be NULL.
83 struct cf_context *cf_switch_context(struct cf_context *cc);
87 * Safe configuration loading
88 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
90 * These functions can be used to to safely load or reload configuration.
94 * Load configuration from @file.
95 * Returns a non-zero value upon error. In that case, all changes to the
96 * configuration specified in the file are undone.
98 int cf_load(const char *file);
101 * Reload configuration from @file, replace the old one.
102 * If @file is NULL, reload all loaded configuration files and re-apply
103 * bits of configuration passed to @cf_set().
104 * Returns a non-zero value upon error. In that case, all configuration
105 * settings are rolled back to the state before calling this function.
107 int cf_reload(const char *file);
110 * Parse some part of configuration passed in @string.
111 * The syntax is the same as in the <<config:,configuration file>>.
112 * Returns a non-zero value upon error. In that case, all changes to the
113 * configuration specified by the already executed parts of the string
116 int cf_set(const char *string);
119 * Sometimes, the configuration is split to multiple files and when only
120 * some of the are loaded, the settings are not consistent -- for example,
121 * they might have been rejected by a commit hook, because a mandatory setting
124 * This function opens a configuration group, in which multiple files can be
125 * loaded and all commit hooks are deferred until the group is closed.
127 void cf_open_group(void);
130 * Close a group opened by @cf_open_group(). Returns a non-zero value upon error,
131 * which usually means that a commit hook has failed.
133 int cf_close_group(void);
136 * Return all configuration items to their initial state before loading the
137 * configuration file. If journalling is disabled, it does nothing.
139 void cf_revert(void);
141 /*** === Data types [[conf_types]] ***/
143 enum cf_class { /** Class of the configuration item. **/
144 CC_END, // end of list
145 CC_STATIC, // single variable or static array
146 CC_DYNAMIC, // dynamically allocated array
147 CC_PARSER, // arbitrary parser function
148 CC_SECTION, // section appears exactly once
149 CC_LIST, // list with 0..many nodes
150 CC_BITMAP // of up to 32 items
153 enum cf_type { /** Type of a single value. **/
154 CT_INT, CT_U64, CT_DOUBLE, // number types
156 CT_STRING, // string type
157 CT_LOOKUP, // in a string table
158 CT_USER // user-defined type
164 * A parser function gets an array of (strdup'ed) strings and a pointer with
165 * the customized information (most likely the target address). It can store
166 * the parsed value anywhere in any way it likes, however it must first call
167 * @cf_journal_block() on the overwritten memory block. It returns an error
168 * message or NULL if everything is all right.
170 typedef char *cf_parser(uns number, char **pars, void *ptr);
172 * A parser function for user-defined types gets a string and a pointer to
173 * the destination variable. It must store the value within [ptr,ptr+size),
174 * where size is fixed for each type. It should not call @cf_journal_block().
176 typedef char *cf_parser1(char *string, void *ptr);
178 * An init- or commit-hook gets a pointer to the section or NULL if this
179 * is the global section. It returns an error message or NULL if everything
180 * is all right. The init-hook should fill in default values (needed for
181 * dynamically allocated nodes of link lists or for filling global variables
182 * that are run-time dependent). The commit-hook should perform sanity
183 * checks and postprocess the parsed values. Commit-hooks must call
184 * @cf_journal_block() too. Caveat! init-hooks for static sections must not
185 * use @cf_malloc() but normal <<memory:xmalloc()>>.
187 typedef char *cf_hook(void *ptr);
189 * Dumps the contents of a variable of a user-defined type.
191 typedef void cf_dumper1(struct fastbuf *fb, void *ptr);
193 * Similar to init-hook, but it copies attributes from another list node
194 * instead of setting the attributes to default values. You have to provide
195 * it if your node contains parsed values and/or sub-lists.
197 typedef char *cf_copier(void *dest, void *src);
199 struct cf_user_type { /** Structure to store information about user-defined variable type. **/
200 uns size; // of the parsed attribute
201 char *name; // name of the type (for dumping)
202 cf_parser1 *parser; // how to parse it
203 cf_dumper1 *dumper; // how to dump the type
207 struct cf_item { /** Single configuration item. **/
208 const char *name; // case insensitive
209 int number; // length of an array or #parameters of a parser (negative means at most)
210 void *ptr; // pointer to a global variable or an offset in a section
212 struct cf_section *sec; // declaration of a section or a list
213 cf_parser *par; // parser function
214 const char * const *lookup; // NULL-terminated sequence of allowed strings for lookups
215 struct cf_user_type *utype; // specification of the user-defined type
217 enum cf_class cls:16; // attribute class
218 enum cf_type type:16; // type of a static or dynamic attribute
221 struct cf_section { /** A section. **/
222 uns size; // 0 for a global block, sizeof(struct) for a section
223 cf_hook *init; // fills in default values (no need to bzero)
224 cf_hook *commit; // verifies parsed data (optional)
225 cf_copier *copy; // copies values from another instance (optional, no need to copy basic attributes)
226 struct cf_item *cfg; // CC_END-terminated array of items
227 uns flags; // for internal use only
235 * You could create the structures manually, but you can use these macros to
240 * Declaration of <<struct_cf_section,`cf_section`>>
241 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
243 * These macros can be used to configure the <<struct_cf_section,`cf_section`>>
248 * Data type of a section.
249 * If you store the section into a structure, use this macro.
251 * Storing a section into a structure is useful mostly when you may have multiple instances of the
252 * section (eg. <<conf_multi,array or list>>).
257 * cnode n; // This one is for the list itself
262 * static struct clist nodes;
264 * static struct cf_section node = {
265 * CF_TYPE(struct list_node),
267 * CF_STRING("name", PTR_TO(struct list_node, name)),
268 * CF_UNS("value", PTR_TO(struct list_node, value)),
273 * static struct cf_section section = {
274 * CF_LIST("node", &nodes, &node),
278 * You could use <<def_CF_STATIC,`CF_STATIC`>> or <<def_CF_DYNAMIC,`CF_DYNAMIC`>>
279 * macros to create arrays.
281 #define CF_TYPE(s) .size = sizeof(s)
283 * An init <<hooks,hook>>.
284 * You can use this to initialize dynamically allocated items (for a dynamic array or list).
285 * The hook returns an error message or NULL if everything was OK.
287 #define CF_INIT(f) .init = (cf_hook*) f
289 * A commit <<hooks,hook>>.
290 * You can use this one to check sanity of loaded data and postprocess them.
291 * You must call @cf_journal_block() if you change anything.
293 * Return error message or NULL if everything went OK.
295 #define CF_COMMIT(f) .commit = (cf_hook*) f
297 * A <<hooks,copy function>>.
298 * You need to provide one for too complicated sections where a memcpy is not
299 * enough to copy it properly. It happens, for example, when you have a dynamically
300 * allocated section containing a list of other sections.
302 * You return an error message or NULL if you succeed.
304 #define CF_COPY(f) .copy = (cf_copier*) f /** **/
305 #define CF_ITEMS .cfg = ( struct cf_item[] ) /** List of sub-items. **/
306 #define CF_END { .cls = CC_END } /** End of the structure. **/
308 * Declaration of a configuration item
309 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
311 * Each of these describe single <<struct_cf_item,configuration item>>. They are mostly
312 * for internal use, do not use them directly unless you really know what you are doing.
316 * Static array of items.
317 * Expects you to allocate the memory and provide pointer to it.
319 #define CF_STATIC(n,p,T,t,c) { .cls = CC_STATIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t*) }
321 * Dynamic array of items.
322 * Expects you to provide pointer to your pointer to data and it will allocate new memory for it
323 * and set your pointer to it.
325 #define CF_DYNAMIC(n,p,T,t,c) { .cls = CC_DYNAMIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t**) }
326 #define CF_PARSER(n,p,f,c) { .cls = CC_PARSER, .name = n, .number = c, .ptr = p, .u.par = (cf_parser*) f } /** A low-level parser. **/
327 #define CF_SECTION(n,p,s) { .cls = CC_SECTION, .name = n, .number = 1, .ptr = p, .u.sec = s } /** A sub-section. **/
328 #define CF_LIST(n,p,s) { .cls = CC_LIST, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,clist*), .u.sec = s } /** A list with sub-items. **/
329 #define CF_BITMAP_INT(n,p) { .cls = CC_BITMAP, .type = CT_INT, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*) } /** A bitmap. **/
330 #define CF_BITMAP_LOOKUP(n,p,t) { .cls = CC_BITMAP, .type = CT_LOOKUP, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*), .u.lookup = t } /** A bitmap with named bits. **/
332 * Basic configuration items
333 * ^^^^^^^^^^^^^^^^^^^^^^^^^
335 * They describe basic data types used in the configuration. This should be enough for
336 * most real-life purposes.
338 * The parameters are as follows:
340 * * @n -- name of the item.
341 * * @p -- pointer to the variable where it shall be stored.
344 #define CF_INT(n,p) CF_STATIC(n,p,INT,int,1) /** Single `int` value. **/
345 #define CF_INT_ARY(n,p,c) CF_STATIC(n,p,INT,int,c) /** Static array of integers. **/
346 #define CF_INT_DYN(n,p,c) CF_DYNAMIC(n,p,INT,int,c) /** Dynamic array of integers. **/
347 #define CF_UNS(n,p) CF_STATIC(n,p,INT,uns,1) /** Single `uns` (`unsigned`) value. **/
348 #define CF_UNS_ARY(n,p,c) CF_STATIC(n,p,INT,uns,c) /** Static array of unsigned integers. **/
349 #define CF_UNS_DYN(n,p,c) CF_DYNAMIC(n,p,INT,uns,c) /** Dynamic array of unsigned integers. **/
350 #define CF_U64(n,p) CF_STATIC(n,p,U64,u64,1) /** Single unsigned 64bit integer (`u64`). **/
351 #define CF_U64_ARY(n,p,c) CF_STATIC(n,p,U64,u64,c) /** Static array of u64s. **/
352 #define CF_U64_DYN(n,p,c) CF_DYNAMIC(n,p,U64,u64,c) /** Dynamic array of u64s. **/
353 #define CF_DOUBLE(n,p) CF_STATIC(n,p,DOUBLE,double,1) /** Single instance of `double`. **/
354 #define CF_DOUBLE_ARY(n,p,c) CF_STATIC(n,p,DOUBLE,double,c) /** Static array of doubles. **/
355 #define CF_DOUBLE_DYN(n,p,c) CF_DYNAMIC(n,p,DOUBLE,double,c) /** Dynamic array of doubles. **/
356 #define CF_IP(n,p) CF_STATIC(n,p,IP,u32,1) /** Single IPv4 address. **/
357 #define CF_IP_ARY(n,p,c) CF_STATIC(n,p,IP,u32,c) /** Static array of IP addresses. **/.
358 #define CF_IP_DYN(n,p,c) CF_DYNAMIC(n,p,IP,u32,c) /** Dynamic array of IP addresses. **/
361 * You provide a pointer to a `char *` variable and it will fill it with
362 * dynamically allocated string. For example:
364 * static char *string = "Default string";
366 * static struct cf_section section = {
368 * CF_STRING("string", &string),
373 #define CF_STRING(n,p) CF_STATIC(n,p,STRING,char*,1)
374 #define CF_STRING_ARY(n,p,c) CF_STATIC(n,p,STRING,char*,c) /** Static array of strings. **/
375 #define CF_STRING_DYN(n,p,c) CF_DYNAMIC(n,p,STRING,char*,c) /** Dynamic array of strings. **/
377 * One string out of a predefined set.
378 * You provide the set as an array of strings terminated by NULL (similar to @argv argument
379 * of main()) as the @t parameter.
381 * The configured variable (pointer to `int`) is set to index of the string.
382 * So, it works this way:
384 * static *strings[] = { "First", "Second", "Third", NULL };
386 * static int variable;
388 * static struct cf_section section = {
390 * CF_LOOKUP("choice", &variable, strings),
395 * Now, if the configuration contains `choice "Second"`, `variable` will be set to 1.
397 #define CF_LOOKUP(n,p,t) { .cls = CC_STATIC, .type = CT_LOOKUP, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,int*), .u.lookup = t }
399 * Static array of strings out of predefined set.
401 #define CF_LOOKUP_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_LOOKUP, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,int*), .u.lookup = t }
403 * Dynamic array of strings out of predefined set.
405 #define CF_LOOKUP_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_LOOKUP, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,int**), .u.lookup = t }
407 * A user-defined type.
408 * See <<custom_parser,creating custom parsers>> section if you want to know more.
410 #define CF_USER(n,p,t) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = 1, .ptr = p, .u.utype = t }
412 * Static array of user-defined types (all of the same type).
413 * See <<custom_parser,creating custom parsers>> section.
415 #define CF_USER_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
417 * Dynamic array of user-defined types.
418 * See <<custom_parser,creating custom parsers>> section.
420 #define CF_USER_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
423 * Any number of dynamic array elements
425 #define CF_ANY_NUM -0x7fffffff
427 #define DARY_LEN(a) GARY_SIZE(a) /** Length of an dynamic array. An alias for `GARY_SIZE`. **/
434 * Each configuration context has one or more <<mempool:,memory pools>>, where all
435 * data related to the configuration are stored.
437 * The following set of functions allocate from these pools. The allocated memory
438 * is valid as long as the current configuration (when the configuration file is
439 * reloaded or rolled back, or the context is deleted, it gets lost).
441 * Memory allocated from within custom parsers should be allocated from the pools.
443 * Please note that the pool is not guaranteed to exist before you call cf_load(),
444 * cf_set(), or cf_getopt() on the particular context.
446 struct mempool *cf_get_pool(void); /** Return a pointer to the current configuration pool. **/
447 void *cf_malloc(uns size); /** Returns @size bytes of memory allocated from the current configuration pool. **/
448 void *cf_malloc_zero(uns size); /** Like @cf_malloc(), but zeroes the memory. **/
449 char *cf_strdup(const char *s); /** Copy a string into @cf_malloc()ed memory. **/
450 char *cf_printf(const char *fmt, ...) FORMAT_CHECK(printf,1,2); /** printf() into @cf_malloc()ed memory. **/
457 * The configuration system uses a simple journaling mechanism, which makes
458 * it possible to undo changes to configuration. A typical example is loading
459 * of configuration by cf_load(): internally, it creates a transaction, applies
460 * all changes specified by the configuration and if one of them fails, the whole
461 * journal is replayed to restore the whole original state. Similarly, cf_reload()
462 * uses the journal to switch between configurations.
464 * In most cases, you need not care about the journal, except when you need
465 * to change some data from a <<hooks,hook>>, or if you want to call cf_modify_item() and then
469 * This function can be used to disable the whole journalling mechanism.
470 * It saves some memory, but it makes undoing of configuration changes impossible,
471 * which breaks for example cf_reload().
473 void cf_set_journalling(int enable);
475 * When a block of memory is about to be changed, put the old value
476 * into journal with this function. You need to call it from a <<hooks,commit hook>>
477 * if you change anything. It is used internally by low-level parsers.
478 * <<custom_parser,Custom parsers>> do not need to call it, it is called
481 void cf_journal_block(void *ptr, uns len);
482 #define CF_JOURNAL_VAR(var) cf_journal_block(&(var), sizeof(var)) // Store a single value into the journal
484 struct cf_journal_item; /** Opaque identifier of the journal state. **/
486 * Starts a new transaction. It returns the current state so you can
487 * get back to it. The @new_pool parameter tells if a new memory pool
488 * should be created and used from now.
490 struct cf_journal_item *cf_journal_new_transaction(uns new_pool);
492 * Marks current state as a complete transaction. The @new_pool
493 * parameter tells if the transaction was created with new memory pool
494 * (the parameter must be the same as the one with
495 * @cf_journal_new_transaction() was called with). The @oldj parameter
496 * is the journal state returned from last
497 * @cf_journal_new_transaction() call.
499 void cf_journal_commit_transaction(uns new_pool, struct cf_journal_item *oldj);
501 * Returns to an old journal state, reverting anything the current
502 * transaction did. The @new_pool parameter must be the same as the
503 * one you used when you created the transaction. The @oldj parameter
504 * is the journal state you got from @cf_journal_new_transaction() --
505 * it is the state to return to.
507 void cf_journal_rollback_transaction(uns new_pool, struct cf_journal_item *oldj);
511 * Section declaration
512 * ~~~~~~~~~~~~~~~~~~~
516 * Plug another top-level section into the configuration system.
517 * @name is the name in the configuration file,
518 * @sec is pointer to the section description.
519 * If @allow_unknown is set to 0 and a variable not described in @sec
520 * is found in the configuration file, it produces an error.
521 * If you set it to 1, all such variables are ignored.
523 * Please note that a single section definition cannot be used in multiple
524 * configuration contexts simultaneously.
526 void cf_declare_section(const char *name, struct cf_section *sec, uns allow_unknown);
528 * Like @cf_declare_section(), but instead of item pointers, the section
529 * contains offsets relative to @ptr. In other words, it does the same
530 * as `CF_SECTION`, but for top-level sections.
532 void cf_declare_rel_section(const char *name, struct cf_section *sec, void *ptr, uns allow_unknown);
534 * If you have a section in a structure and you want to initialize it
535 * (eg. if you want a copy of default values outside the configuration),
536 * you can use this. It initializes it recursively.
538 * This is used mostly internally. You probably do not need it.
540 void cf_init_section(const char *name, struct cf_section *sec, void *ptr, uns do_bzero);
544 * Parsers for basic types
545 * ~~~~~~~~~~~~~~~~~~~~~~~
547 * Each of them gets a string to parse and pointer to store the value.
548 * It returns either NULL or error message.
550 * The parsers support units. See <<config:units,their list>>.
552 char *cf_parse_int(const char *str, int *ptr); /** Parser for integers. **/
553 char *cf_parse_u64(const char *str, u64 *ptr); /** Parser for 64 unsigned integers. **/
554 char *cf_parse_double(const char *str, double *ptr); /** Parser for doubles. **/
555 char *cf_parse_ip(const char *p, u32 *varp); /** Parser for IP addresses. **/
562 * Direct access to configuration items.
563 * You probably should not need this, but in your do, you have to handle
564 * <<journal,journalling>> yourself.
568 * List of operations used on items.
569 * This macro is used to generate internal source code,
570 * but you may be interested in the list of operations it creates.
572 * Each operation corresponds to the same-named operation
573 * described in <<config:operations,configuration syntax>>.
575 #define CF_OPERATIONS T(CLOSE) T(SET) T(CLEAR) T(ALL) \
576 T(APPEND) T(PREPEND) T(REMOVE) T(EDIT) T(AFTER) T(BEFORE) T(COPY) T(RESET)
577 /* Closing brace finishes previous block.
578 * Basic attributes (static, dynamic, parsed) can be used with SET.
579 * Dynamic arrays can be used with SET, APPEND, PREPEND.
580 * Sections can be used with SET.
581 * Lists can be used with everything. */
583 enum cf_operation { CF_OPERATIONS }; /** Allowed operations on items. See <<def_CF_OPERATIONS,`CF_OPERATIONS`>> for list (they have an `OP_` prefix -- it means you use `OP_SET` instead of just `SET`). **/
587 * Searches for a configuration item called @name.
588 * If it is found, it is copied into @item and NULL is returned.
589 * Otherwise, an error is returned and @item is zeroed.
591 char *cf_find_item(const char *name, struct cf_item *item);
593 * Performs a single operation on a given item.
595 char *cf_modify_item(struct cf_item *item, enum cf_operation op, int number, char **pars);
605 * Write the current state of all configuration items into @fb.
607 void cf_dump_sections(struct fastbuf *fb);