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 * If you do not create contexts explicitly, the library will create one for you
25 * and you need not care, as long as you use a single configuration file.
27 * In whole 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
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);
53 * Return a pointer to the current context, or create the default context
54 * if there is no context active.
56 struct cf_context *cf_obtain_context(void);
59 * Set name of default configuration file. May be NULL if there should be
61 * FIXME: Explain where it is used
63 void cf_set_default_file(char *name);
66 * Set name of environment variable used to override the name of the default
67 * configuration file. May be NULL if there should be no such variable.
69 void cf_set_env_override(char *name);
71 /*** === Data types [[conf_types]] ***/
73 enum cf_class { /** Class of the configuration item. **/
74 CC_END, // end of list
75 CC_STATIC, // single variable or static array
76 CC_DYNAMIC, // dynamically allocated array
77 CC_PARSER, // arbitrary parser function
78 CC_SECTION, // section appears exactly once
79 CC_LIST, // list with 0..many nodes
80 CC_BITMAP // of up to 32 items
83 enum cf_type { /** Type of a single value. **/
84 CT_INT, CT_U64, CT_DOUBLE, // number types
86 CT_STRING, // string type
87 CT_LOOKUP, // in a string table
88 CT_USER // user-defined type
94 * A parser function gets an array of (strdup'ed) strings and a pointer with
95 * the customized information (most likely the target address). It can store
96 * the parsed value anywhere in any way it likes, however it must first call
97 * @cf_journal_block() on the overwritten memory block. It returns an error
98 * message or NULL if everything is all right.
100 typedef char *cf_parser(uns number, char **pars, void *ptr);
102 * A parser function for user-defined types gets a string and a pointer to
103 * the destination variable. It must store the value within [ptr,ptr+size),
104 * where size is fixed for each type. It should not call @cf_journal_block().
106 typedef char *cf_parser1(char *string, void *ptr);
108 * An init- or commit-hook gets a pointer to the section or NULL if this
109 * is the global section. It returns an error message or NULL if everything
110 * is all right. The init-hook should fill in default values (needed for
111 * dynamically allocated nodes of link lists or for filling global variables
112 * that are run-time dependent). The commit-hook should perform sanity
113 * checks and postprocess the parsed values. Commit-hooks must call
114 * @cf_journal_block() too. Caveat! init-hooks for static sections must not
115 * use @cf_malloc() but normal <<memory:xmalloc()>>.
117 typedef char *cf_hook(void *ptr);
119 * Dumps the contents of a variable of a user-defined type.
121 typedef void cf_dumper1(struct fastbuf *fb, void *ptr);
123 * Similar to init-hook, but it copies attributes from another list node
124 * instead of setting the attributes to default values. You have to provide
125 * it if your node contains parsed values and/or sub-lists.
127 typedef char *cf_copier(void *dest, void *src);
129 struct cf_user_type { /** Structure to store information about user-defined variable type. **/
130 uns size; // of the parsed attribute
131 char *name; // name of the type (for dumping)
132 cf_parser1 *parser; // how to parse it
133 cf_dumper1 *dumper; // how to dump the type
137 struct cf_item { /** Single configuration item. **/
138 const char *name; // case insensitive
139 int number; // length of an array or #parameters of a parser (negative means at most)
140 void *ptr; // pointer to a global variable or an offset in a section
142 struct cf_section *sec; // declaration of a section or a list
143 cf_parser *par; // parser function
144 const char * const *lookup; // NULL-terminated sequence of allowed strings for lookups
145 struct cf_user_type *utype; // specification of the user-defined type
147 enum cf_class cls:16; // attribute class
148 enum cf_type type:16; // type of a static or dynamic attribute
151 struct cf_section { /** A section. **/
152 uns size; // 0 for a global block, sizeof(struct) for a section
153 cf_hook *init; // fills in default values (no need to bzero)
154 cf_hook *commit; // verifies parsed data (optional)
155 cf_copier *copy; // copies values from another instance (optional, no need to copy basic attributes)
156 struct cf_item *cfg; // CC_END-terminated array of items
157 uns flags; // for internal use only
165 * You could create the structures manually, but you can use these macros to
170 * Declaration of <<struct_cf_section,`cf_section`>>
171 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
173 * These macros can be used to configure the <<struct_cf_section,`cf_section`>>
178 * Data type of a section.
179 * If you store the section into a structure, use this macro.
181 * Storing a section into a structure is useful mostly when you may have multiple instances of the
182 * section (eg. <<conf_multi,array or list>>).
187 * cnode n; // This one is for the list itself
192 * static struct clist nodes;
194 * static struct cf_section node = {
195 * CF_TYPE(struct list_node),
197 * CF_STRING("name", PTR_TO(struct list_node, name)),
198 * CF_UNS("value", PTR_TO(struct list_node, value)),
203 * static struct cf_section section = {
204 * CF_LIST("node", &nodes, &node),
208 * You could use <<def_CF_STATIC,`CF_STATIC`>> or <<def_CF_DYNAMIC,`CF_DYNAMIC`>>
209 * macros to create arrays.
211 #define CF_TYPE(s) .size = sizeof(s)
213 * An init <<hooks,hook>>.
214 * You can use this to initialize dynamically allocated items (for a dynamic array or list).
215 * The hook returns an error message or NULL if everything was OK.
217 #define CF_INIT(f) .init = (cf_hook*) f
219 * A commit <<hooks,hook>>.
220 * You can use this one to check sanity of loaded data and postprocess them.
221 * You must call @cf_journal_block() if you change anything.
223 * Return error message or NULL if everything went OK.
225 #define CF_COMMIT(f) .commit = (cf_hook*) f
227 * A <<hooks,copy function>>.
228 * You need to provide one for too complicated sections where a memcpy is not
229 * enough to copy it properly. It happens, for example, when you have a dynamically
230 * allocated section containing a list of other sections.
232 * You return an error message or NULL if you succeed.
234 #define CF_COPY(f) .copy = (cf_copier*) f /** **/
235 #define CF_ITEMS .cfg = ( struct cf_item[] ) /** List of sub-items. **/
236 #define CF_END { .cls = CC_END } /** End of the structure. **/
238 * Declaration of a configuration item
239 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
241 * Each of these describe single <<struct_cf_item,configuration item>>. They are mostly
242 * for internal use, do not use them directly unless you really know what you are doing.
246 * Static array of items.
247 * Expects you to allocate the memory and provide pointer to it.
249 #define CF_STATIC(n,p,T,t,c) { .cls = CC_STATIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t*) }
251 * Dynamic array of items.
252 * Expects you to provide pointer to your pointer to data and it will allocate new memory for it
253 * and set your pointer to it.
255 #define CF_DYNAMIC(n,p,T,t,c) { .cls = CC_DYNAMIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t**) }
256 #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. **/
257 #define CF_SECTION(n,p,s) { .cls = CC_SECTION, .name = n, .number = 1, .ptr = p, .u.sec = s } /** A sub-section. **/
258 #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. **/
259 #define CF_BITMAP_INT(n,p) { .cls = CC_BITMAP, .type = CT_INT, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*) } /** A bitmap. **/
260 #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. **/
262 * Basic configuration items
263 * ^^^^^^^^^^^^^^^^^^^^^^^^^
265 * They describe basic data types used in the configuration. This should be enough for
266 * most real-life purposes.
268 * The parameters are as follows:
270 * * @n -- name of the item.
271 * * @p -- pointer to the variable where it shall be stored.
274 #define CF_INT(n,p) CF_STATIC(n,p,INT,int,1) /** Single `int` value. **/
275 #define CF_INT_ARY(n,p,c) CF_STATIC(n,p,INT,int,c) /** Static array of integers. **/
276 #define CF_INT_DYN(n,p,c) CF_DYNAMIC(n,p,INT,int,c) /** Dynamic array of integers. **/
277 #define CF_UNS(n,p) CF_STATIC(n,p,INT,uns,1) /** Single `uns` (`unsigned`) value. **/
278 #define CF_UNS_ARY(n,p,c) CF_STATIC(n,p,INT,uns,c) /** Static array of unsigned integers. **/
279 #define CF_UNS_DYN(n,p,c) CF_DYNAMIC(n,p,INT,uns,c) /** Dynamic array of unsigned integers. **/
280 #define CF_U64(n,p) CF_STATIC(n,p,U64,u64,1) /** Single unsigned 64bit integer (`u64`). **/
281 #define CF_U64_ARY(n,p,c) CF_STATIC(n,p,U64,u64,c) /** Static array of u64s. **/
282 #define CF_U64_DYN(n,p,c) CF_DYNAMIC(n,p,U64,u64,c) /** Dynamic array of u64s. **/
283 #define CF_DOUBLE(n,p) CF_STATIC(n,p,DOUBLE,double,1) /** Single instance of `double`. **/
284 #define CF_DOUBLE_ARY(n,p,c) CF_STATIC(n,p,DOUBLE,double,c) /** Static array of doubles. **/
285 #define CF_DOUBLE_DYN(n,p,c) CF_DYNAMIC(n,p,DOUBLE,double,c) /** Dynamic array of doubles. **/
286 #define CF_IP(n,p) CF_STATIC(n,p,IP,u32,1) /** Single IPv4 address. **/
287 #define CF_IP_ARY(n,p,c) CF_STATIC(n,p,IP,u32,c) /** Static array of IP addresses. **/.
288 #define CF_IP_DYN(n,p,c) CF_DYNAMIC(n,p,IP,u32,c) /** Dynamic array of IP addresses. **/
291 * You provide a pointer to a `char *` variable and it will fill it with
292 * dynamically allocated string. For example:
294 * static char *string = "Default string";
296 * static struct cf_section section = {
298 * CF_STRING("string", &string),
303 #define CF_STRING(n,p) CF_STATIC(n,p,STRING,char*,1)
304 #define CF_STRING_ARY(n,p,c) CF_STATIC(n,p,STRING,char*,c) /** Static array of strings. **/
305 #define CF_STRING_DYN(n,p,c) CF_DYNAMIC(n,p,STRING,char*,c) /** Dynamic array of strings. **/
307 * One string out of a predefined set.
308 * You provide the set as an array of strings terminated by NULL (similar to @argv argument
309 * of main()) as the @t parameter.
311 * The configured variable (pointer to `int`) is set to index of the string.
312 * So, it works this way:
314 * static *strings[] = { "First", "Second", "Third", NULL };
316 * static int variable;
318 * static struct cf_section section = {
320 * CF_LOOKUP("choice", &variable, strings),
325 * Now, if the configuration contains `choice "Second"`, `variable` will be set to 1.
327 #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 }
329 * Static array of strings out of predefined set.
331 #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 }
333 * Dynamic array of strings out of predefined set.
335 #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 }
337 * A user-defined type.
338 * See <<custom_parser,creating custom parsers>> section if you want to know more.
340 #define CF_USER(n,p,t) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = 1, .ptr = p, .u.utype = t }
342 * Static array of user-defined types (all of the same type).
343 * See <<custom_parser,creating custom parsers>> section.
345 #define CF_USER_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
347 * Dynamic array of user-defined types.
348 * See <<custom_parser,creating custom parsers>> section.
350 #define CF_USER_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
353 * Any number of dynamic array elements
355 #define CF_ANY_NUM -0x7fffffff
357 #define DARY_LEN(a) ((uns*)a)[-1] /** Length of an dynamic array. **/
358 #define DARY_ALLOC(type,len,val...) ((struct { uns l; type a[len]; }) { .l = len, .a = { val } }).a
359 // creates a static instance of a dynamic array
366 * Each configuration context has one or more <<mempool:,memory pools>>, where all
367 * data related to the configuration are stored.
369 * The following set of functions allocate from these pools. The allocated memory
370 * is valid as long as the current configuration (when the configuration file is
371 * reloaded or rolled back, or the context is deleted, it gets lost).
373 * Memory allocated from within custom parsers should be allocated from the pools.
375 struct mempool *cf_get_pool(void); /** Return a pointer to the current configuration pool. **/
376 void *cf_malloc(uns size); /** Returns @size bytes of memory allocated from the current configuration pool. **/
377 void *cf_malloc_zero(uns size); /** Like @cf_malloc(), but zeroes the memory. **/
378 char *cf_strdup(const char *s); /** Copy a string into @cf_malloc()ed memory. **/
379 char *cf_printf(const char *fmt, ...) FORMAT_CHECK(printf,1,2); /** printf() into @cf_malloc()ed memory. **/
386 * For error recovery when <<reload,reloading configuration>>.
388 extern uns cf_need_journal; /** Is the journal needed? If you do not reload configuration, you set this to 0 and gain a little more performance and free memory. **/
390 * When a block of memory is about to be changed, put the old value
391 * into journal with this function. You need to call it from a <<hooks,commit hook>>
392 * if you change anything. It is used internally by low-level parsers.
393 * <<custom_parser,Custom parsers>> do not need to call it, it is called
396 void cf_journal_block(void *ptr, uns len);
397 #define CF_JOURNAL_VAR(var) cf_journal_block(&(var), sizeof(var)) // Store single value into journal.
401 * Section declaration
402 * ~~~~~~~~~~~~~~~~~~~
406 * Plug another top-level section into the configuration system.
407 * @name is the name in the configuration file,
408 * @sec is pointer to the section description.
409 * If @allow_unknown is set to 0 and a variable not described in @sec
410 * is found in the configuration file, it produces an error.
411 * If you set it to 1, all such variables are ignored.
413 void cf_declare_section(const char *name, struct cf_section *sec, uns allow_unknown);
415 * If you have a section in a structure and you want to initialize it
416 * (eg. if you want a copy of default values outside the configuration),
417 * you can use this. It initializes it recursively.
419 * This is used mostly internally. You probably do not need it.
421 void cf_init_section(const char *name, struct cf_section *sec, void *ptr, uns do_bzero);
425 * Parsers for basic types
426 * ~~~~~~~~~~~~~~~~~~~~~~~
428 * Each of them gets a string to parse and pointer to store the value.
429 * It returns either NULL or error message.
431 * The parsers support units. See <<config:units,their list>>.
433 char *cf_parse_int(const char *str, int *ptr); /** Parser for integers. **/
434 char *cf_parse_u64(const char *str, u64 *ptr); /** Parser for 64 unsigned integers. **/
435 char *cf_parse_double(const char *str, double *ptr); /** Parser for doubles. **/
436 char *cf_parse_ip(const char *p, u32 *varp); /** Parser for IP addresses. **/