2 * UCW Library -- Configuration files
4 * (c) 2001--2006 Robert Spalek <robert@ucw.cz>
5 * (c) 2003--2012 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>
20 * Configuration contexts
21 * ~~~~~~~~~~~~~~~~~~~~~~
23 * The state of the configuration parser is stored within a configuration context.
24 * One such context is automatically created during initialization of the library
25 * and you need not care about more, as long as you use a single configuration file.
27 * In full generality, you can define as many context as you wish and switch
28 * between them. Each thread has its own pointer to the current context, which
29 * must not be shared with other threads.
32 /** Create a new configuration context. **/
33 struct cf_context *cf_new_context(void);
36 * Free a configuration context. The context must not be set as current
37 * for any thread, nor can it be the default context.
39 * All configuration settings made within the context are rolled back
40 * (except when journalling is turned off). All memory allocated on behalf
41 * of the context is freed, which includes memory obtained by calls to
44 void cf_free_context(struct cf_context *cc);
47 * Make the given configuration context current and return the previously
48 * active context. Both the new and the old context may be NULL.
50 struct cf_context *cf_switch_context(struct cf_context *cc);
54 * Safe configuration loading
55 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
57 * These functions can be used to to safely load or reload configuration.
60 int cf_reload(const char *file); /** Reload configuration from @file, replace the old one. **/
61 int cf_load(const char *file); /** Load configuration from @file. If @file is NULL, reload all loaded configuration files. **/
63 * Parse some part of configuration passed in @string.
64 * The syntax is the same as in the <<config:,configuration file>>.
66 int cf_set(const char *string);
68 /*** === Data types [[conf_types]] ***/
70 enum cf_class { /** Class of the configuration item. **/
71 CC_END, // end of list
72 CC_STATIC, // single variable or static array
73 CC_DYNAMIC, // dynamically allocated array
74 CC_PARSER, // arbitrary parser function
75 CC_SECTION, // section appears exactly once
76 CC_LIST, // list with 0..many nodes
77 CC_BITMAP // of up to 32 items
80 enum cf_type { /** Type of a single value. **/
81 CT_INT, CT_U64, CT_DOUBLE, // number types
83 CT_STRING, // string type
84 CT_LOOKUP, // in a string table
85 CT_USER // user-defined type
91 * A parser function gets an array of (strdup'ed) strings and a pointer with
92 * the customized information (most likely the target address). It can store
93 * the parsed value anywhere in any way it likes, however it must first call
94 * @cf_journal_block() on the overwritten memory block. It returns an error
95 * message or NULL if everything is all right.
97 typedef char *cf_parser(uns number, char **pars, void *ptr);
99 * A parser function for user-defined types gets a string and a pointer to
100 * the destination variable. It must store the value within [ptr,ptr+size),
101 * where size is fixed for each type. It should not call @cf_journal_block().
103 typedef char *cf_parser1(char *string, void *ptr);
105 * An init- or commit-hook gets a pointer to the section or NULL if this
106 * is the global section. It returns an error message or NULL if everything
107 * is all right. The init-hook should fill in default values (needed for
108 * dynamically allocated nodes of link lists or for filling global variables
109 * that are run-time dependent). The commit-hook should perform sanity
110 * checks and postprocess the parsed values. Commit-hooks must call
111 * @cf_journal_block() too. Caveat! init-hooks for static sections must not
112 * use @cf_malloc() but normal <<memory:xmalloc()>>.
114 typedef char *cf_hook(void *ptr);
116 * Dumps the contents of a variable of a user-defined type.
118 typedef void cf_dumper1(struct fastbuf *fb, void *ptr);
120 * Similar to init-hook, but it copies attributes from another list node
121 * instead of setting the attributes to default values. You have to provide
122 * it if your node contains parsed values and/or sub-lists.
124 typedef char *cf_copier(void *dest, void *src);
126 struct cf_user_type { /** Structure to store information about user-defined variable type. **/
127 uns size; // of the parsed attribute
128 char *name; // name of the type (for dumping)
129 cf_parser1 *parser; // how to parse it
130 cf_dumper1 *dumper; // how to dump the type
134 struct cf_item { /** Single configuration item. **/
135 const char *name; // case insensitive
136 int number; // length of an array or #parameters of a parser (negative means at most)
137 void *ptr; // pointer to a global variable or an offset in a section
139 struct cf_section *sec; // declaration of a section or a list
140 cf_parser *par; // parser function
141 const char * const *lookup; // NULL-terminated sequence of allowed strings for lookups
142 struct cf_user_type *utype; // specification of the user-defined type
144 enum cf_class cls:16; // attribute class
145 enum cf_type type:16; // type of a static or dynamic attribute
148 struct cf_section { /** A section. **/
149 uns size; // 0 for a global block, sizeof(struct) for a section
150 cf_hook *init; // fills in default values (no need to bzero)
151 cf_hook *commit; // verifies parsed data (optional)
152 cf_copier *copy; // copies values from another instance (optional, no need to copy basic attributes)
153 struct cf_item *cfg; // CC_END-terminated array of items
154 uns flags; // for internal use only
162 * You could create the structures manually, but you can use these macros to
167 * Declaration of <<struct_cf_section,`cf_section`>>
168 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
170 * These macros can be used to configure the <<struct_cf_section,`cf_section`>>
175 * Data type of a section.
176 * If you store the section into a structure, use this macro.
178 * Storing a section into a structure is useful mostly when you may have multiple instances of the
179 * section (eg. <<conf_multi,array or list>>).
184 * cnode n; // This one is for the list itself
189 * static struct clist nodes;
191 * static struct cf_section node = {
192 * CF_TYPE(struct list_node),
194 * CF_STRING("name", PTR_TO(struct list_node, name)),
195 * CF_UNS("value", PTR_TO(struct list_node, value)),
200 * static struct cf_section section = {
201 * CF_LIST("node", &nodes, &node),
205 * You could use <<def_CF_STATIC,`CF_STATIC`>> or <<def_CF_DYNAMIC,`CF_DYNAMIC`>>
206 * macros to create arrays.
208 #define CF_TYPE(s) .size = sizeof(s)
210 * An init <<hooks,hook>>.
211 * You can use this to initialize dynamically allocated items (for a dynamic array or list).
212 * The hook returns an error message or NULL if everything was OK.
214 #define CF_INIT(f) .init = (cf_hook*) f
216 * A commit <<hooks,hook>>.
217 * You can use this one to check sanity of loaded data and postprocess them.
218 * You must call @cf_journal_block() if you change anything.
220 * Return error message or NULL if everything went OK.
222 #define CF_COMMIT(f) .commit = (cf_hook*) f
224 * A <<hooks,copy function>>.
225 * You need to provide one for too complicated sections where a memcpy is not
226 * enough to copy it properly. It happens, for example, when you have a dynamically
227 * allocated section containing a list of other sections.
229 * You return an error message or NULL if you succeed.
231 #define CF_COPY(f) .copy = (cf_copier*) f /** **/
232 #define CF_ITEMS .cfg = ( struct cf_item[] ) /** List of sub-items. **/
233 #define CF_END { .cls = CC_END } /** End of the structure. **/
235 * Declaration of a configuration item
236 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
238 * Each of these describe single <<struct_cf_item,configuration item>>. They are mostly
239 * for internal use, do not use them directly unless you really know what you are doing.
243 * Static array of items.
244 * Expects you to allocate the memory and provide pointer to it.
246 #define CF_STATIC(n,p,T,t,c) { .cls = CC_STATIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t*) }
248 * Dynamic array of items.
249 * Expects you to provide pointer to your pointer to data and it will allocate new memory for it
250 * and set your pointer to it.
252 #define CF_DYNAMIC(n,p,T,t,c) { .cls = CC_DYNAMIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t**) }
253 #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. **/
254 #define CF_SECTION(n,p,s) { .cls = CC_SECTION, .name = n, .number = 1, .ptr = p, .u.sec = s } /** A sub-section. **/
255 #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. **/
256 #define CF_BITMAP_INT(n,p) { .cls = CC_BITMAP, .type = CT_INT, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*) } /** A bitmap. **/
257 #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. **/
259 * Basic configuration items
260 * ^^^^^^^^^^^^^^^^^^^^^^^^^
262 * They describe basic data types used in the configuration. This should be enough for
263 * most real-life purposes.
265 * The parameters are as follows:
267 * * @n -- name of the item.
268 * * @p -- pointer to the variable where it shall be stored.
271 #define CF_INT(n,p) CF_STATIC(n,p,INT,int,1) /** Single `int` value. **/
272 #define CF_INT_ARY(n,p,c) CF_STATIC(n,p,INT,int,c) /** Static array of integers. **/
273 #define CF_INT_DYN(n,p,c) CF_DYNAMIC(n,p,INT,int,c) /** Dynamic array of integers. **/
274 #define CF_UNS(n,p) CF_STATIC(n,p,INT,uns,1) /** Single `uns` (`unsigned`) value. **/
275 #define CF_UNS_ARY(n,p,c) CF_STATIC(n,p,INT,uns,c) /** Static array of unsigned integers. **/
276 #define CF_UNS_DYN(n,p,c) CF_DYNAMIC(n,p,INT,uns,c) /** Dynamic array of unsigned integers. **/
277 #define CF_U64(n,p) CF_STATIC(n,p,U64,u64,1) /** Single unsigned 64bit integer (`u64`). **/
278 #define CF_U64_ARY(n,p,c) CF_STATIC(n,p,U64,u64,c) /** Static array of u64s. **/
279 #define CF_U64_DYN(n,p,c) CF_DYNAMIC(n,p,U64,u64,c) /** Dynamic array of u64s. **/
280 #define CF_DOUBLE(n,p) CF_STATIC(n,p,DOUBLE,double,1) /** Single instance of `double`. **/
281 #define CF_DOUBLE_ARY(n,p,c) CF_STATIC(n,p,DOUBLE,double,c) /** Static array of doubles. **/
282 #define CF_DOUBLE_DYN(n,p,c) CF_DYNAMIC(n,p,DOUBLE,double,c) /** Dynamic array of doubles. **/
283 #define CF_IP(n,p) CF_STATIC(n,p,IP,u32,1) /** Single IPv4 address. **/
284 #define CF_IP_ARY(n,p,c) CF_STATIC(n,p,IP,u32,c) /** Static array of IP addresses. **/.
285 #define CF_IP_DYN(n,p,c) CF_DYNAMIC(n,p,IP,u32,c) /** Dynamic array of IP addresses. **/
288 * You provide a pointer to a `char *` variable and it will fill it with
289 * dynamically allocated string. For example:
291 * static char *string = "Default string";
293 * static struct cf_section section = {
295 * CF_STRING("string", &string),
300 #define CF_STRING(n,p) CF_STATIC(n,p,STRING,char*,1)
301 #define CF_STRING_ARY(n,p,c) CF_STATIC(n,p,STRING,char*,c) /** Static array of strings. **/
302 #define CF_STRING_DYN(n,p,c) CF_DYNAMIC(n,p,STRING,char*,c) /** Dynamic array of strings. **/
304 * One string out of a predefined set.
305 * You provide the set as an array of strings terminated by NULL (similar to @argv argument
306 * of main()) as the @t parameter.
308 * The configured variable (pointer to `int`) is set to index of the string.
309 * So, it works this way:
311 * static *strings[] = { "First", "Second", "Third", NULL };
313 * static int variable;
315 * static struct cf_section section = {
317 * CF_LOOKUP("choice", &variable, strings),
322 * Now, if the configuration contains `choice "Second"`, `variable` will be set to 1.
324 #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 }
326 * Static array of strings out of predefined set.
328 #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 }
330 * Dynamic array of strings out of predefined set.
332 #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 }
334 * A user-defined type.
335 * See <<custom_parser,creating custom parsers>> section if you want to know more.
337 #define CF_USER(n,p,t) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = 1, .ptr = p, .u.utype = t }
339 * Static array of user-defined types (all of the same type).
340 * See <<custom_parser,creating custom parsers>> section.
342 #define CF_USER_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
344 * Dynamic array of user-defined types.
345 * See <<custom_parser,creating custom parsers>> section.
347 #define CF_USER_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
350 * Any number of dynamic array elements
352 #define CF_ANY_NUM -0x7fffffff
354 #define DARY_LEN(a) ((uns*)a)[-1] /** Length of an dynamic array. **/
355 #define DARY_ALLOC(type,len,val...) ((struct { uns l; type a[len]; }) { .l = len, .a = { val } }).a
356 // creates a static instance of a dynamic array
363 * Each configuration context has one or more <<mempool:,memory pools>>, where all
364 * data related to the configuration are stored.
366 * The following set of functions allocate from these pools. The allocated memory
367 * is valid as long as the current configuration (when the configuration file is
368 * reloaded or rolled back, or the context is deleted, it gets lost).
370 * Memory allocated from within custom parsers should be allocated from the pools.
372 struct mempool *cf_get_pool(void); /** Return a pointer to the current configuration pool. **/
373 void *cf_malloc(uns size); /** Returns @size bytes of memory allocated from the current configuration pool. **/
374 void *cf_malloc_zero(uns size); /** Like @cf_malloc(), but zeroes the memory. **/
375 char *cf_strdup(const char *s); /** Copy a string into @cf_malloc()ed memory. **/
376 char *cf_printf(const char *fmt, ...) FORMAT_CHECK(printf,1,2); /** printf() into @cf_malloc()ed memory. **/
383 * The configuration system uses journaling to safely reload
384 * configuration. It begins a transaction and tries to load the
385 * configuration. If it fails, it restores the original state.
387 * The behaviour of journal is described in <<reload,reloading configuration>>.
390 * By default, the configuration mechanism remembers all changes in a journal,
391 * so that the configuration can be rolled back or reloaded. This function
392 * can be used to disable journalling, which saves some memory.
394 void cf_set_journalling(int enable);
396 * When a block of memory is about to be changed, put the old value
397 * into journal with this function. You need to call it from a <<hooks,commit hook>>
398 * if you change anything. It is used internally by low-level parsers.
399 * <<custom_parser,Custom parsers>> do not need to call it, it is called
402 void cf_journal_block(void *ptr, uns len);
403 #define CF_JOURNAL_VAR(var) cf_journal_block(&(var), sizeof(var)) // Store single value into journal.
405 struct cf_journal_item; /** Opaque identifier of the journal state. **/
407 * Starts a new transaction. It returns the current state so you can
408 * get back to it. The @new_pool parameter tells if a new memory pool
409 * should be created and used from now.
411 struct cf_journal_item *cf_journal_new_transaction(uns new_pool);
413 * Marks current state as a complete transaction. The @new_pool
414 * parameter tells if the transaction was created with new memory pool
415 * (the parameter must be the same as the one with
416 * @cf_journal_new_transaction() was called with). The @oldj parameter
417 * is the journal state returned from last
418 * @cf_journal_new_transaction() call.
420 void cf_journal_commit_transaction(uns new_pool, struct cf_journal_item *oldj);
422 * Returns to an old journal state, reverting anything the current
423 * transaction did. The @new_pool parameter must be the same as the
424 * one you used when you created the transaction. The @oldj parameter
425 * is the journal state you got from @cf_journal_new_transaction() --
426 * it is the state to return to.
428 void cf_journal_rollback_transaction(uns new_pool, struct cf_journal_item *oldj);
432 * Section declaration
433 * ~~~~~~~~~~~~~~~~~~~
437 * Plug another top-level section into the configuration system.
438 * @name is the name in the configuration file,
439 * @sec is pointer to the section description.
440 * If @allow_unknown is set to 0 and a variable not described in @sec
441 * is found in the configuration file, it produces an error.
442 * If you set it to 1, all such variables are ignored.
444 void cf_declare_section(const char *name, struct cf_section *sec, uns allow_unknown);
446 * If you have a section in a structure and you want to initialize it
447 * (eg. if you want a copy of default values outside the configuration),
448 * you can use this. It initializes it recursively.
450 * This is used mostly internally. You probably do not need it.
452 void cf_init_section(const char *name, struct cf_section *sec, void *ptr, uns do_bzero);
456 * Parsers for basic types
457 * ~~~~~~~~~~~~~~~~~~~~~~~
459 * Each of them gets a string to parse and pointer to store the value.
460 * It returns either NULL or error message.
462 * The parsers support units. See <<config:units,their list>>.
464 char *cf_parse_int(const char *str, int *ptr); /** Parser for integers. **/
465 char *cf_parse_u64(const char *str, u64 *ptr); /** Parser for 64 unsigned integers. **/
466 char *cf_parse_double(const char *str, double *ptr); /** Parser for doubles. **/
467 char *cf_parse_ip(const char *p, u32 *varp); /** Parser for IP addresses. **/
474 * Direct access to configuration items.
475 * You probably should not need this.
479 * List of operations used on items.
480 * This macro is used to generate internal source code,
481 * but you may be interested in the list of operations it creates.
483 * Each operation corresponds to the same-named operation
484 * described in <<config:operations,configuration syntax>>.
486 #define CF_OPERATIONS T(CLOSE) T(SET) T(CLEAR) T(ALL) \
487 T(APPEND) T(PREPEND) T(REMOVE) T(EDIT) T(AFTER) T(BEFORE) T(COPY) T(RESET)
488 /* Closing brace finishes previous block.
489 * Basic attributes (static, dynamic, parsed) can be used with SET.
490 * Dynamic arrays can be used with SET, APPEND, PREPEND.
491 * Sections can be used with SET.
492 * Lists can be used with everything. */
494 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`). **/
498 * Searches for a configuration item called @name.
499 * If it is found, it is copied into @item and NULL is returned.
500 * Otherwise, an error is returned and @item is zeroed.
502 char *cf_find_item(const char *name, struct cf_item *item);
504 * Performs a single operation on a given item.
506 char *cf_modify_item(struct cf_item *item, enum cf_operation op, int number, char **pars);
516 * Take everything and write it into @fb.
518 void cf_dump_sections(struct fastbuf *fb);