3 /* log - a generic logging facility in the spirit of log4j */
5 /* Copyright (c) 2003, 2004 Martin Quinson. All rights reserved. */
7 /* This program is free software; you can redistribute it and/or modify it
8 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include "xbt_modinter.h"
16 #include "xbt/sysdep.h"
18 #include "xbt/error.h"
19 #include "xbt/dynar.h"
21 /** \addtogroup XBT_log
23 * This section describes the API to the log functions used
24 * everywhere in this project.
26 \section log_overview Overview
28 This is an adaptation of the log4c project, which is dead upstream, and
29 which I was given the permission to fork under the LGPL licence by the
30 authors. log4c itself was loosely based on the Apache project's Log4J,
31 Log4CC, etc. project. Because C is not object oriented, a lot had to change.
33 There is 3 main concepts: category, priority and appender. These three
34 concepts work together to enable developers to log messages according to
35 message type and priority, and to control at runtime how these messages are
36 formatted and where they are reported.
38 \section log_cat Category hierarchy
40 The first and foremost advantage of any logging API over plain printf()
41 resides in its ability to disable certain log statements while allowing
42 others to print unhindered. This capability assumes that the logging space,
43 that is, the space of all possible logging statements, is categorized
44 according to some developer-chosen criteria.
46 This observation led to choosing category as the central concept of the
47 system. Every category is declared by providing a name and an optional
48 parent. If no parent is explicitly named, the root category, LOG_ROOT_CAT is
49 the category's parent.
51 A category is created by a macro call at the top level of a file. A
52 category can be created with any one of the following macros:
54 - \ref XBT_LOG_NEW_CATEGORY(MyCat); Create a new root
55 - \ref XBT_LOG_NEW_SUBCATEGORY(MyCat, ParentCat);
56 Create a new category being child of the category ParentCat
57 - \ref XBT_LOG_NEW_DEFAULT_CATEGORY(MyCat);
58 Like XBT_LOG_NEW_CATEGORY, but the new category is the default one
60 - \ref XBT_LOG_NEW_DEFAULT_SUBCATEGORY(MyCat, ParentCat);
61 Like XBT_LOG_NEW_SUBCATEGORY, but the new category is the default one
64 The parent cat can be defined in the same file or in another file (in
65 which case you want to use the \ref XBT_LOG_EXTERNAL_CATEGORY macro to make
66 it visible in the current file), but each category may have only one
69 Typically, there will be a Category for each module and sub-module, so you
70 can independently control logging for each module.
72 For a list of all existing categories, please refer to the \ref XBT_log_cats section.
74 \section log_pri Priority
76 A category may be assigned a threshold priorty. The set of priorites are
77 defined by the \ref e_xbt_log_priority_t enum. All logging request under
78 this priority will be discarded.
80 If a given category is not assigned a threshold priority, then it inherits
81 one from its closest ancestor with an assigned threshold. To ensure that all
82 categories can eventually inherit a threshold, the root category always has
83 an assigned threshold priority.
85 Logging requests are made by invoking a logging macro on a category. All of
86 the macros have a printf-style format string followed by arguments. If you
87 compile with the -Wall option, gcc will warn you for unmatched arguments, ie
88 when you pass a pointer to a string where an integer was specified by the
89 format. This is usualy a good idea.
91 Because most C compilers do not support vararg macros, there is a version of
92 the macro for any number of arguments from 0 to 6. The macro name ends with
93 the total number of arguments.
95 Here is an example of the most basic type of macro. This is a logging
96 request with priority <i>warning</i>.
98 <code>CLOG5(MyCat, gras_log_priority_warning, "Values are: %d and '%s'", 5,
101 A logging request is said to be enabled if its priority is higher than or
102 equal to the threshold priority of its category. Otherwise, the request is
103 said to be disabled. A category without an assigned priority will inherit
104 one from the hierarchy.
106 It is possible to use any non-negative integer as a priority. If, as in the
107 example, one of the standard priorites is used, then there is a convenience
108 macro that is typically used instead. For example, the above example is
109 equivalent to the shorter:
111 <code>CWARN4(MyCat, "Values are: %d and '%s'", 5, "oops");</code>
113 \subsection log_subcat Using a default category
115 If \ref XBT_LOG_NEW_DEFAULT_SUBCATEGORY(MyCat, Parent) or
116 \ref XBT_LOG_NEW_DEFAULT_CATEGORY(MyCat) is used to create the
117 category, then the even shorter form can be used:
119 <code>WARN3("Values are: %d and '%s'", 5, "oops");</code>
121 Only one default category can be created per file, though multiple
122 non-defaults can be created and used.
124 \section log_example Example
126 Here is a more complete example:
131 / * create a category and a default subcategory * /
132 XBT_LOG_NEW_CATEGORY(VSS);
133 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(SA, VSS);
136 / * Now set the parent's priority. (the string would typcially be a runtime option) * /
137 xbt_log_control_set("SA.thresh=3");
139 / * This request is enabled, because WARNING >= INFO. * /
140 CWARN2(VSS, "Low fuel level.");
142 / * This request is disabled, because DEBUG < INFO. * /
143 CDEBUG2(VSS, "Starting search for nearest gas station.");
145 / * The default category SA inherits its priority from VSS. Thus,
146 the following request is enabled because INFO >= INFO. * /
147 INFO1("Located nearest gas station.");
149 / * This request is disabled, because DEBUG < INFO. * /
150 DEBUG1("Exiting gas station search");
154 \section log_conf Configuration
155 Configuration is typically done during program initialization by invoking
156 the xbt_log_control_set() method. The control string passed to it typically
157 comes from the command line. Look at the documentation for that function for
158 the format of the control string.
160 Any SimGrid program can furthermore be configured at run time by passing a
161 --xbt-log argument on the command line (--gras-log, --msg-log and
162 --surf-log are synonyms). You can provide several of those arguments to
163 change the setting of several categories.
165 \section log_perf Performance
167 Clever design insures efficiency. Except for the first invocation, a
168 disabled logging request requires an a single comparison of a static
169 variable to a constant.
171 There is also compile time constant, \ref XBT_LOG_STATIC_THRESHOLD, which
172 causes all logging requests with a lower priority to be optimized to 0 cost
173 by the compiler. By setting it to gras_log_priority_infinite, all logging
174 requests are statically disabled and cost nothing. Released executables
175 might be compiled with
176 \verbatim-DXBT_LOG_STATIC_THRESHOLD=gras_log_priority_infinite\endverbatim
178 Compiling with the \verbatim-DNLOG\endverbatim option disables all logging
179 requests at compilation time while the \verbatim-DNDEBUG\endverbatim disables
180 the requests of priority below INFO.
182 \section log_app Appenders
184 Each category has an optional appender. An appender is a pointer to a
185 structure which starts with a pointer to a doAppend() function. DoAppend()
186 prints a message to a log.
188 When a category is passed a message by one of the logging macros, the
189 category performs the following actions:
191 - if the category has an appender, the message is passed to the
192 appender's doAppend() function,
193 - if 'willLogToParent' is true for the category, the message is passed
194 to the category's parent.
196 By default, only the root category have an appender, and 'willLogToParent'
197 is true for any other category. This situation causes all messages to be
198 logged by the root category's appender.
200 The default appender function currently prints to stderr, and no other one
201 exist, even if more would be needed, like the one able to send the logs to a
202 remote dedicated server, or other ones offering different output formats.
203 This is on our TODO list for quite a while now, but your help would be
206 \section log_misc Misc and Caveats
208 - Do not use any of the macros that start with '_'.
209 - Log4J has a 'rolling file appender' which you can select with a run-time
210 option and specify the max file size. This would be a nice default for
211 non-kernel applications.
212 - Careful, category names are global variables.
219 Pour utiliser les logs, tu déjà faire, non ? Tu colle sur la ligne de
220 commande un ou plusieurs arguments de la forme
221 --gras-log="<réglage> [<reglage>+]" (ou sans " si t'as pas d'espace)
222 chaque réglage étant de la forme:
223 <canal>.thres=<priorité>
224 Les différents réglages sont lus de gauche à droite.
225 "root.thres=debug root.thres=critical" ferme tout, normalement.
231 e_xbt_log_priority_t thresh;
232 } s_xbt_log_setting_t,*xbt_log_setting_t;
234 static xbt_dynar_t xbt_log_settings=NULL;
235 static void _free_setting(void *s) {
236 xbt_log_setting_t set=(xbt_log_setting_t)s;
239 /* free(set); FIXME: uncommenting this leads to segfault when more than one chunk is passed as gras-log */
243 const char *xbt_log_priority_names[8] = {
254 s_xbt_log_category_t _XBT_LOGV(XBT_LOG_ROOT_CAT) = {
256 "root", xbt_log_priority_uninitialized, 0,
260 XBT_LOG_NEW_CATEGORY(xbt,"All XBT categories (simgrid toolbox)");
261 XBT_LOG_NEW_CATEGORY(surf,"All SURF categories");
262 XBT_LOG_NEW_CATEGORY(msg,"All MSG categories");
263 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(log,xbt,"Loggings from the logging mechanism itself");
265 void xbt_log_init(int *argc,char **argv) {
269 /* Set logs and init log submodule */
270 for (i=1; i<*argc; i++) {
271 if (!strncmp(argv[i],"--gras-log=",strlen("--gras-log=")) ||
272 !strncmp(argv[i],"--surf-log=",strlen("--surf-log=")) ||
273 !strncmp(argv[i],"--msg-log=",strlen("--msg-log=")) ||
274 !strncmp(argv[i],"--xbt-log=",strlen("--xbt-log="))) {
275 opt=strchr(argv[i],'=');
277 xbt_log_control_set(opt);
278 DEBUG1("Did apply '%s' as log setting",opt);
279 /*remove this from argv*/
280 for (j=i+1; j<*argc; j++) {
285 i--; /* compensate effect of next loop incrementation */
290 void xbt_log_exit(void) {
291 VERB0("Exiting log");
292 xbt_dynar_free(&xbt_log_settings);
296 static void _apply_control(xbt_log_category_t cat) {
298 xbt_log_setting_t setting=NULL;
301 if (!xbt_log_settings)
304 xbt_assert0(cat,"NULL category");
305 xbt_assert(cat->name);
307 xbt_dynar_foreach(xbt_log_settings,cursor,setting) {
308 xbt_assert0(setting,"Damnit, NULL cat in the list");
309 xbt_assert1(setting->catname,"NULL setting(=%p)->catname",(void*)setting);
311 if (!strcmp(setting->catname,cat->name)) {
314 xbt_log_threshold_set(cat, setting->thresh);
315 xbt_dynar_cursor_rm(xbt_log_settings,&cursor);
317 if (cat->threshold <= xbt_log_priority_debug) {
318 s_xbt_log_event_t _log_ev =
319 {cat,xbt_log_priority_debug,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
320 _xbt_log_event_log(&_log_ev,
321 "Apply settings for category '%s': set threshold to %s (=%d)",
323 xbt_log_priority_names[cat->threshold], cat->threshold);
327 if (!found && cat->threshold <= xbt_log_priority_verbose) {
328 s_xbt_log_event_t _log_ev =
329 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
330 _xbt_log_event_log(&_log_ev,
331 "Category '%s': inherited threshold = %s (=%d)",
333 xbt_log_priority_names[cat->threshold], cat->threshold);
338 void _xbt_log_event_log( xbt_log_event_t ev, const char *fmt, ...) {
339 xbt_log_category_t cat = ev->cat;
340 va_start(ev->ap, fmt);
342 xbt_log_appender_t appender = cat->appender;
343 if (appender != NULL) {
344 appender->do_append(appender, ev, fmt);
346 if (!cat->willLogToParent)
354 static void _cat_init(xbt_log_category_t category) {
355 if (category == &_XBT_LOGV(XBT_LOG_ROOT_CAT)) {
356 category->threshold = xbt_log_priority_info;
357 category->appender = xbt_log_default_appender;
359 xbt_log_parent_set(category, category->parent);
361 _apply_control(category);
365 * This gets called the first time a category is referenced and performs the
367 * Also resets threshold to inherited!
369 int _xbt_log_cat_init(e_xbt_log_priority_t priority,
370 xbt_log_category_t category) {
374 return priority >= category->threshold;
377 void xbt_log_parent_set(xbt_log_category_t cat,
378 xbt_log_category_t parent) {
380 xbt_assert0(cat,"NULL category to be given a parent");
381 xbt_assert1(parent,"The parent category of %s is NULL",cat->name);
383 /* unlink from current parent */
384 if (cat->threshold != xbt_log_priority_uninitialized) {
385 xbt_log_category_t* cpp = &parent->firstChild;
386 while(*cpp != cat && *cpp != NULL) {
387 cpp = &(*cpp)->nextSibling;
389 xbt_assert(*cpp == cat);
390 *cpp = cat->nextSibling;
394 cat->parent = parent;
395 cat->nextSibling = parent->firstChild;
396 parent->firstChild = cat;
398 /* Make sure parent is initialized */
399 if (parent->threshold == xbt_log_priority_uninitialized) {
404 cat->threshold = parent->threshold;
405 cat->isThreshInherited = 1;
406 } /* log_setParent */
408 static void _set_inherited_thresholds(xbt_log_category_t cat) {
409 xbt_log_category_t child = cat->firstChild;
410 for( ; child != NULL; child = child->nextSibling) {
411 if (child->isThreshInherited) {
412 if (cat != &_XBT_LOGV(log))
413 VERB3("Set category threshold of %s to %s (=%d)",
414 child->name,xbt_log_priority_names[cat->threshold],cat->threshold);
415 child->threshold = cat->threshold;
416 _set_inherited_thresholds(child);
421 void xbt_log_threshold_set(xbt_log_category_t cat,
422 e_xbt_log_priority_t threshold) {
423 cat->threshold = threshold;
424 cat->isThreshInherited = 0;
425 _set_inherited_thresholds(cat);
428 static void _xbt_log_parse_setting(const char* control_string,
429 xbt_log_setting_t set) {
430 const char *name, *dot, *eq;
433 if (!*control_string)
435 DEBUG1("Parse log setting '%s'",control_string);
437 control_string += strspn(control_string, " ");
438 name = control_string;
439 control_string += strcspn(control_string, ".= ");
440 dot = control_string;
441 control_string += strcspn(control_string, "= ");
443 control_string += strcspn(control_string, " ");
445 xbt_assert1(*dot == '.' && *eq == '=',
446 "Invalid control string '%s'",control_string);
448 if (!strncmp(dot + 1, "thresh", min(eq - dot - 1,strlen("thresh")))) {
450 char *neweq=xbt_strdup(eq+1);
453 while (*(++p) != '\0') {
454 if (*p >= 'a' && *p <= 'z') {
459 DEBUG1("New priority name = %s",neweq);
460 for (i=0; i<xbt_log_priority_infinite-1; i++) {
461 if (!strncmp(xbt_log_priority_names[i],neweq,p-eq)) {
462 DEBUG1("This is priority %d",i);
466 if (i<xbt_log_priority_infinite-1) {
469 xbt_assert1(FALSE,"Unknown priority name: %s",eq+1);
474 snprintf(buff,min(512,eq - dot - 1),"%s",dot+1);
475 xbt_assert1(FALSE,"Unknown setting of the log category: %s",buff);
477 set->catname=(char*)xbt_malloc(dot - name+1);
479 strncpy(set->catname,name,dot-name);
480 set->catname[dot-name]='\0'; /* Just in case */
481 DEBUG1("This is for cat '%s'", set->catname);
484 static xbt_error_t _xbt_log_cat_searchsub(xbt_log_category_t cat,char *name,
485 /*OUT*/xbt_log_category_t*whereto) {
487 xbt_log_category_t child;
489 if (!strcmp(cat->name,name)) {
493 for(child=cat->firstChild ; child != NULL; child = child->nextSibling) {
494 errcode=_xbt_log_cat_searchsub(child,name,whereto);
495 if (errcode==no_error)
498 return mismatch_error;
501 static void _cleanup_double_spaces(char *s) {
524 if (e ^ !isspace(*p))
535 * \param control_string What to parse
537 * Typically passed a command-line argument. The string has the syntax:
539 * ( [category] "." [keyword] "=" value (" ")... )...
541 * where [category] is one the category names and keyword is one of the
544 * thresh value is an integer priority level. Sets the category's
545 * threshold priority.
548 * This routine may only be called once and that must be before any other
549 * logging command! Typically, this is done from main().
551 void xbt_log_control_set(const char* control_string) {
553 xbt_log_setting_t set;
558 DEBUG1("Parse log settings '%s'",control_string);
559 if (control_string == NULL)
561 if (xbt_log_settings == NULL)
562 xbt_log_settings = xbt_dynar_new(sizeof(xbt_log_setting_t),
565 set = xbt_new(s_xbt_log_setting_t,1);
566 cs=xbt_strdup(control_string);
568 _cleanup_double_spaces(cs);
571 xbt_log_category_t cat;
581 _xbt_log_parse_setting(p,set);
583 errcode = _xbt_log_cat_searchsub(&_XBT_LOGV(root),set->catname,&cat);
584 if (errcode == mismatch_error) {
585 DEBUG0("Store for further application");
586 DEBUG1("push %p to the settings",(void*)set);
587 xbt_dynar_push(xbt_log_settings,&set);
588 /* malloc in advance the next slot */
589 set = xbt_new(s_xbt_log_setting_t,1);
591 DEBUG0("Apply directly");
593 xbt_log_threshold_set(cat,set->thresh);
600 void xbt_log_appender_set(xbt_log_category_t cat, xbt_log_appender_t app) {