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 Dans gras, tu ne te contente pas d'écrire des choses à l'écran, mais tu
220 écris sur un sujet particulier (notion de canal) des choses d'une gravité
221 particulière. Il y a 7 niveaux de gravité.
222 trace: tracer les entrées dans une fonction, retour de fonction
223 (famille de macros XBT_IN/XBT_OUT)
224 debug: pour t'aider à mettre au point le module, potentiellement tres bavard
225 verbose: quelques infos succintes sur les internals du module
226 info: niveau normal, ton de la conversation
227 warning: problème potentiel, mais auquel on a su faire face
228 error: problème qui t'as empêché de faire ton job
229 critical: juste avant de mourir
231 Quand on compile avec -DNDEBUG (par défaut dans le paquet Debian), tout ce
232 qui est '>= verbose' est supprimé au moment de la compilation. Retiré du
235 Ensuite, tu écris dans un canal particulier. Tous les canaux sont rangés en
236 arbre. Il faudrait faire un ptit script qui fouille les sources à la
237 recherche des macros XBT_LOG_NEW_* utilisées pour créer des canaux. Le
238 dernier argument de ces macros est ignoré dans le source. Il est destiné à
239 être la documentation de la chose en une ligne. En gros, ca fait:
260 +--raw_trp (Je devrais tuer ce module, un jour)
266 Et ensuite les utilisateurs peuvent choisir le niveau de gravité qui les
267 interresse sur tel ou tel sujet.
269 Toute la mécanique de logging repose sur des variables statiques dont le nom
270 dépend du nom du canal.
271 => attention aux conflits de nom de canal
272 => il faut une macro XBT_LOG dans chaque fichier où tu fais des logs.
274 XBT_LOG_NEW_CATEGORY: nouveau canal sous "root". Rare, donc.
275 XBT_LOG_NEW_SUBCATEGORY: nouveau canal dont on précise le père.
276 XBT_LOG_DEFAULT_CATEGORY: indique quel est le canal par défaut dans ce fichier
277 XBT_LOG_NEW_DEFAULT_CATEGORY: Crèe un canal et l'utilise par défaut
278 XBT_LOG_NEW_DEFAULT_SUBCATEGORY: devine
279 XBT_LOG_EXTERNAL_CATEGORY: quand tu veux utiliser par défaut un canal créé
280 dans un autre fichier.
282 Une fois que ton canal est créé, tu l'utilise avec les macros LOG, DEBUG,
283 VERB, WARN, ERROR et CRITICAL. Il faut que tu donne le nombre d'arguments
284 après le nom de macro. Exemple: LOG2("My name is %s %s","Martin","Quinson")
285 Si tu veux préciser explicitement le canal où écrire, ajoute un C devant le
286 nom de la macro. Exemple: CCRITICAL0(module, "Cannot initialize GRAS")
288 Toutes ces macros (enfin, ce en quoi elles se réécrivent) vérifient leurs
289 arguments comme printf le fait lorsqu'on compile avec gcc.
290 LOG1("name: %d","toto"); donne un warning, et donc une erreur en mode
293 Enfin, tu peux tester si un canal est ouvert à une priorité donnée (pour
294 préparer plus de débug, par exemple. Dans le parseur, je fais du pretty
295 printing sur ce qu'il faut parser dans ce cas).
296 XBT_LOG_ISENABLED(catName, priority) Le second argument doit être une valeur
297 de e_xbt_log_priority_t (log.h). Par exemple: xbt_log_priority_verbose
299 Voila sur comment mettre des logs dans ton code. N'hesite pas à faire pleins
300 de canaux différents pour des aspects différents de ton code. En
301 particulier, dans les dict, j'ai un canal pour l'ajout, le retrait, le
302 netoyage du code après suppression et ainsi de suite. De cette façon, je
303 peux choisir qui m'interresse.
306 Pour utiliser les logs, tu déjà faire, non ? Tu colle sur la ligne de
307 commande un ou plusieurs arguments de la forme
308 --gras-log="<réglage> [<reglage>+]" (ou sans " si t'as pas d'espace)
309 chaque réglage étant de la forme:
310 <canal>.thres=<priorité>
311 Les différents réglages sont lus de gauche à droite.
312 "root.thres=debug root.thres=critical" ferme tout, normalement.
318 e_xbt_log_priority_t thresh;
319 } s_xbt_log_setting_t,*xbt_log_setting_t;
321 static xbt_dynar_t xbt_log_settings=NULL;
322 static void _free_setting(void *s) {
323 xbt_log_setting_t set=(xbt_log_setting_t)s;
326 /* free(set); FIXME: uncommenting this leads to segfault when more than one chunk is passed as gras-log */
330 const char *xbt_log_priority_names[8] = {
341 s_xbt_log_category_t _XBT_LOGV(XBT_LOG_ROOT_CAT) = {
343 "root", xbt_log_priority_uninitialized, 0,
347 XBT_LOG_NEW_CATEGORY(xbt,"All XBT categories (simgrid toolbox)");
348 XBT_LOG_NEW_CATEGORY(surf,"All SURF categories");
349 XBT_LOG_NEW_CATEGORY(msg,"All MSG categories");
350 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(log,xbt,"Loggings from the logging mechanism itself");
352 void xbt_log_init(int *argc,char **argv, const char *defaultlog) {
357 /* Set logs and init log submodule */
358 for (i=1; i<*argc; i++) {
359 if (!strncmp(argv[i],"--gras-log=",strlen("--gras-log=")) ||
360 !strncmp(argv[i],"--surf-log=",strlen("--surf-log=")) ||
361 !strncmp(argv[i],"--msg-log=",strlen("--msg-log=")) ||
362 !strncmp(argv[i],"--xbt-log=",strlen("--xbt-log="))) {
364 opt=strchr(argv[i],'=');
366 xbt_log_control_set(opt);
367 DEBUG1("Did apply '%s' as log setting",opt);
368 /*remove this from argv*/
369 for (j=i+1; j<*argc; j++) {
374 i--; /* compensate effect of next loop incrementation */
377 if (!found && defaultlog) {
378 xbt_log_control_set(defaultlog);
382 void xbt_log_exit(void) {
383 VERB0("Exiting log");
384 xbt_dynar_free(&xbt_log_settings);
388 static void _apply_control(xbt_log_category_t cat) {
390 xbt_log_setting_t setting=NULL;
393 if (!xbt_log_settings)
396 xbt_assert0(cat,"NULL category");
397 xbt_assert(cat->name);
399 xbt_dynar_foreach(xbt_log_settings,cursor,setting) {
400 xbt_assert0(setting,"Damnit, NULL cat in the list");
401 xbt_assert1(setting->catname,"NULL setting(=%p)->catname",(void*)setting);
403 if (!strcmp(setting->catname,cat->name)) {
406 xbt_log_threshold_set(cat, setting->thresh);
407 xbt_dynar_cursor_rm(xbt_log_settings,&cursor);
409 if (cat->threshold <= xbt_log_priority_verbose) {
410 s_xbt_log_event_t _log_ev =
411 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
412 _xbt_log_event_log(&_log_ev,
413 "Apply settings for category '%s': set threshold to %s (=%d)",
415 xbt_log_priority_names[cat->threshold], cat->threshold);
419 if (!found && cat->threshold <= xbt_log_priority_verbose) {
420 s_xbt_log_event_t _log_ev =
421 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
422 _xbt_log_event_log(&_log_ev,
423 "Category '%s': inherited threshold = %s (=%d)",
425 xbt_log_priority_names[cat->threshold], cat->threshold);
430 void _xbt_log_event_log( xbt_log_event_t ev, const char *fmt, ...) {
431 xbt_log_category_t cat = ev->cat;
432 va_start(ev->ap, fmt);
434 xbt_log_appender_t appender = cat->appender;
435 if (appender != NULL) {
436 appender->do_append(appender, ev, fmt);
438 if (!cat->willLogToParent)
446 static void _cat_init(xbt_log_category_t category) {
447 if (category == &_XBT_LOGV(XBT_LOG_ROOT_CAT)) {
448 category->threshold = xbt_log_priority_info;
449 category->appender = xbt_log_default_appender;
451 xbt_log_parent_set(category, category->parent);
453 _apply_control(category);
457 * This gets called the first time a category is referenced and performs the
459 * Also resets threshold to inherited!
461 int _xbt_log_cat_init(e_xbt_log_priority_t priority,
462 xbt_log_category_t category) {
466 return priority >= category->threshold;
469 void xbt_log_parent_set(xbt_log_category_t cat,
470 xbt_log_category_t parent) {
472 xbt_assert0(cat,"NULL category to be given a parent");
473 xbt_assert1(parent,"The parent category of %s is NULL",cat->name);
475 /* unlink from current parent */
476 if (cat->threshold != xbt_log_priority_uninitialized) {
477 xbt_log_category_t* cpp = &parent->firstChild;
478 while(*cpp != cat && *cpp != NULL) {
479 cpp = &(*cpp)->nextSibling;
481 xbt_assert(*cpp == cat);
482 *cpp = cat->nextSibling;
486 cat->parent = parent;
487 cat->nextSibling = parent->firstChild;
488 parent->firstChild = cat;
490 /* Make sure parent is initialized */
491 if (parent->threshold == xbt_log_priority_uninitialized) {
496 cat->threshold = parent->threshold;
497 cat->isThreshInherited = 1;
498 } /* log_setParent */
500 static void _set_inherited_thresholds(xbt_log_category_t cat) {
501 xbt_log_category_t child = cat->firstChild;
502 for( ; child != NULL; child = child->nextSibling) {
503 if (child->isThreshInherited) {
504 if (cat != &_XBT_LOGV(log))
505 VERB3("Set category threshold of %s to %s (=%d)",
506 child->name,xbt_log_priority_names[cat->threshold],cat->threshold);
507 child->threshold = cat->threshold;
508 _set_inherited_thresholds(child);
513 void xbt_log_threshold_set(xbt_log_category_t cat,
514 e_xbt_log_priority_t threshold) {
515 cat->threshold = threshold;
516 cat->isThreshInherited = 0;
517 _set_inherited_thresholds(cat);
520 static void _xbt_log_parse_setting(const char* control_string,
521 xbt_log_setting_t set) {
522 const char *name, *dot, *eq;
525 if (!*control_string)
527 DEBUG1("Parse log setting '%s'",control_string);
529 control_string += strspn(control_string, " ");
530 name = control_string;
531 control_string += strcspn(control_string, ".= ");
532 dot = control_string;
533 control_string += strcspn(control_string, "= ");
535 control_string += strcspn(control_string, " ");
537 xbt_assert1(*dot == '.' && *eq == '=',
538 "Invalid control string '%s'",control_string);
540 if (!strncmp(dot + 1, "thresh", min(eq - dot - 1,strlen("thresh")))) {
542 char *neweq=xbt_strdup(eq+1);
545 while (*(++p) != '\0') {
546 if (*p >= 'a' && *p <= 'z') {
551 DEBUG1("New priority name = %s",neweq);
552 for (i=0; i<xbt_log_priority_infinite-1; i++) {
553 if (!strncmp(xbt_log_priority_names[i],neweq,p-eq)) {
554 DEBUG1("This is priority %d",i);
558 if (i<xbt_log_priority_infinite-1) {
561 xbt_assert1(FALSE,"Unknown priority name: %s",eq+1);
566 snprintf(buff,min(512,eq - dot - 1),"%s",dot+1);
567 xbt_assert1(FALSE,"Unknown setting of the log category: %s",buff);
569 set->catname=(char*)xbt_malloc(dot - name+1);
571 strncpy(set->catname,name,dot-name);
572 set->catname[dot-name]='\0'; /* Just in case */
573 DEBUG1("This is for cat '%s'", set->catname);
576 static xbt_error_t _xbt_log_cat_searchsub(xbt_log_category_t cat,char *name,
577 /*OUT*/xbt_log_category_t*whereto) {
579 xbt_log_category_t child;
581 if (!strcmp(cat->name,name)) {
585 for(child=cat->firstChild ; child != NULL; child = child->nextSibling) {
586 errcode=_xbt_log_cat_searchsub(child,name,whereto);
587 if (errcode==no_error)
590 return mismatch_error;
593 static void _cleanup_double_spaces(char *s) {
616 if (e ^ !isspace(*p))
627 * \param control_string What to parse
629 * Typically passed a command-line argument. The string has the syntax:
631 * ( [category] "." [keyword] "=" value (" ")... )...
633 * where [category] is one the category names and keyword is one of the
636 * thresh value is an integer priority level. Sets the category's
637 * threshold priority.
640 * This routine may only be called once and that must be before any other
641 * logging command! Typically, this is done from main().
643 void xbt_log_control_set(const char* control_string) {
645 xbt_log_setting_t set;
650 DEBUG1("Parse log settings '%s'",control_string);
651 if (control_string == NULL)
653 if (xbt_log_settings == NULL)
654 xbt_log_settings = xbt_dynar_new(sizeof(xbt_log_setting_t),
657 set = xbt_new(s_xbt_log_setting_t,1);
658 cs=xbt_strdup(control_string);
660 _cleanup_double_spaces(cs);
663 xbt_log_category_t cat;
673 _xbt_log_parse_setting(p,set);
675 errcode = _xbt_log_cat_searchsub(&_XBT_LOGV(root),set->catname,&cat);
676 if (errcode == mismatch_error) {
677 DEBUG0("Store for further application");
678 DEBUG1("push %p to the settings",(void*)set);
679 xbt_dynar_push(xbt_log_settings,&set);
680 /* malloc in advance the next slot */
681 set = xbt_new(s_xbt_log_setting_t,1);
683 DEBUG0("Apply directly");
685 xbt_log_threshold_set(cat,set->thresh);
692 void xbt_log_appender_set(xbt_log_category_t cat, xbt_log_appender_t app) {