1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * Apache example_hooks module. Provide demonstrations of how modules do things.
19 * It is not meant to be used in a production server. Since it participates
20 * in all of the processing phases, it could conceivable interfere with
21 * the proper operation of other modules -- particularly the ones related
22 * to security.
23 *
24 * In the interest of brevity, all functions and structures internal to
25 * this module, but which may have counterparts in *real* modules, are
26 * prefixed with 'x_' instead of 'example_'.
27 *
28 * To use mod_example_hooks, configure the Apache build with
29 * --enable-example-hooks and compile. Set up a <Location> block in your
30 * configuration file like so:
31 *
32 * <Location /example>
33 * SetHandler example-hooks-handler
34 * </Location>
35 *
36 * When you look at that location on your server, you will see a backtrace of
37 * the callbacks that have been invoked up to that point. See the ErrorLog for
38 * more information on code paths that touch mod_example_hooks.
39 *
40 * IMPORTANT NOTES
41 * ===============
42 *
43 * Do NOT use this module on a production server. It attaches itself to every
44 * phase of the server runtime operations including startup, shutdown and
45 * request processing, and produces copious amounts of logging data. This will
46 * negatively affect server performance.
47 *
48 * Do NOT use mod_example_hooks as the basis for your own code. This module
49 * implements every callback hook offered by the Apache core, and your
50 * module will almost certainly not have to implement this much. If you
51 * want a simple module skeleton to start development, use apxs -g.
52 *
53 * XXX TO DO XXX
54 * =============
55 *
56 * * Enable HTML backtrace entries for more callbacks that are not directly
57 * associated with a request
58 * * Make sure every callback that posts an HTML backtrace entry does so in the * right category, so nothing gets overwritten
59 * * Implement some logic to show what happens in the parent, and what in the
60 * child(ren)
61 */
62
63 #include "httpd.h"
64 #include "http_config.h"
65 #include "http_core.h"
66 #include "http_log.h"
67 #include "http_main.h"
68 #include "http_protocol.h"
69 #include "http_request.h"
70 #include "util_script.h"
71 #include "http_connection.h"
72 #ifdef HAVE_UNIX_SUEXEC
73 #include "unixd.h"
74 #endif
75 #include "scoreboard.h"
76 #include "mpm_common.h"
77
78 #include "apr_strings.h"
79
80 #include <stdio.h>
81
82 /*--------------------------------------------------------------------------*/
83 /* */
84 /* Data declarations. */
85 /* */
86 /* Here are the static cells and structure declarations private to our */
87 /* module. */
88 /* */
89 /*--------------------------------------------------------------------------*/
90
91 /*
92 * Sample configuration record. Used for both per-directory and per-server
93 * configuration data.
94 *
95 * It's perfectly reasonable to have two different structures for the two
96 * different environments. The same command handlers will be called for
97 * both, though, so the handlers need to be able to tell them apart. One
98 * possibility is for both structures to start with an int which is 0 for
99 * one and 1 for the other.
100 *
101 * Note that while the per-directory and per-server configuration records are
102 * available to most of the module handlers, they should be treated as
103 * READ-ONLY by all except the command and merge handlers. Sometimes handlers
104 * are handed a record that applies to the current location by implication or
105 * inheritance, and modifying it will change the rules for other locations.
106 */
107 typedef struct x_cfg {
108 int cmode; /* Environment to which record applies
109 * (directory, server, or combination).
110 */
111 #define CONFIG_MODE_SERVER 1
112 #define CONFIG_MODE_DIRECTORY 2
113 #define CONFIG_MODE_COMBO 3 /* Shouldn't ever happen. */
114 int local; /* Boolean: "Example" directive declared
115 * here?
116 */
117 int congenital; /* Boolean: did we inherit an "Example"? */
118 char *trace; /* Pointer to trace string. */
119 char *loc; /* Location to which this record applies. */
120 } x_cfg;
121
122 /*
123 * String pointer to hold the startup trace. No harm working with a global until
124 * the server is (may be) multi-threaded.
125 */
126 static const char *trace = NULL;
127
128 /*
129 * Declare ourselves so the configuration routines can find and know us.
130 * We'll fill it in at the end of the module.
131 */
132 module AP_MODULE_DECLARE_DATA example_hooks_module;
133
134 /*--------------------------------------------------------------------------*/
135 /* */
136 /* The following pseudo-prototype declarations illustrate the parameters */
137 /* passed to command handlers for the different types of directive */
138 /* syntax. If an argument was specified in the directive definition */
139 /* (look for "command_rec" below), it's available to the command handler */
140 /* via the (void *) info field in the cmd_parms argument passed to the */
141 /* handler (cmd->info for the examples below). */
142 /* */
143 /*--------------------------------------------------------------------------*/
144
145 /*
146 * Command handler for a NO_ARGS directive. Declared in the command_rec
147 * list with
148 * AP_INIT_NO_ARGS("directive", function, mconfig, where, help)
149 *
150 * static const char *handle_NO_ARGS(cmd_parms *cmd, void *mconfig);
151 */
152
153 /*
154 * Command handler for a RAW_ARGS directive. The "args" argument is the text
155 * of the commandline following the directive itself. Declared in the
156 * command_rec list with
157 * AP_INIT_RAW_ARGS("directive", function, mconfig, where, help)
158 *
159 * static const char *handle_RAW_ARGS(cmd_parms *cmd, void *mconfig,
160 * const char *args);
161 */
162
163 /*
164 * Command handler for a FLAG directive. The single parameter is passed in
165 * "bool", which is either zero or not for Off or On respectively.
166 * Declared in the command_rec list with
167 * AP_INIT_FLAG("directive", function, mconfig, where, help)
168 *
169 * static const char *handle_FLAG(cmd_parms *cmd, void *mconfig, int bool);
170 */
171
172 /*
173 * Command handler for a TAKE1 directive. The single parameter is passed in
174 * "word1". Declared in the command_rec list with
175 * AP_INIT_TAKE1("directive", function, mconfig, where, help)
176 *
177 * static const char *handle_TAKE1(cmd_parms *cmd, void *mconfig,
178 * char *word1);
179 */
180
181 /*
182 * Command handler for a TAKE2 directive. TAKE2 commands must always have
183 * exactly two arguments. Declared in the command_rec list with
184 * AP_INIT_TAKE2("directive", function, mconfig, where, help)
185 *
186 * static const char *handle_TAKE2(cmd_parms *cmd, void *mconfig,
187 * char *word1, char *word2);
188 */
189
190 /*
191 * Command handler for a TAKE3 directive. Like TAKE2, these must have exactly
192 * three arguments, or the parser complains and doesn't bother calling us.
193 * Declared in the command_rec list with
194 * AP_INIT_TAKE3("directive", function, mconfig, where, help)
195 *
196 * static const char *handle_TAKE3(cmd_parms *cmd, void *mconfig,
197 * char *word1, char *word2, char *word3);
198 */
199
200 /*
201 * Command handler for a TAKE12 directive. These can take either one or two
202 * arguments.
203 * - word2 is a NULL pointer if no second argument was specified.
204 * Declared in the command_rec list with
205 * AP_INIT_TAKE12("directive", function, mconfig, where, help)
206 *
207 * static const char *handle_TAKE12(cmd_parms *cmd, void *mconfig,
208 * char *word1, char *word2);
209 */
210
211 /*
212 * Command handler for a TAKE123 directive. A TAKE123 directive can be given,
213 * as might be expected, one, two, or three arguments.
214 * - word2 is a NULL pointer if no second argument was specified.
215 * - word3 is a NULL pointer if no third argument was specified.
216 * Declared in the command_rec list with
217 * AP_INIT_TAKE123("directive", function, mconfig, where, help)
218 *
219 * static const char *handle_TAKE123(cmd_parms *cmd, void *mconfig,
220 * char *word1, char *word2, char *word3);
221 */
222
223 /*
224 * Command handler for a TAKE13 directive. Either one or three arguments are
225 * permitted - no two-parameters-only syntax is allowed.
226 * - word2 and word3 are NULL pointers if only one argument was specified.
227 * Declared in the command_rec list with
228 * AP_INIT_TAKE13("directive", function, mconfig, where, help)
229 *
230 * static const char *handle_TAKE13(cmd_parms *cmd, void *mconfig,
231 * char *word1, char *word2, char *word3);
232 */
233
234 /*
235 * Command handler for a TAKE23 directive. At least two and as many as three
236 * arguments must be specified.
237 * - word3 is a NULL pointer if no third argument was specified.
238 * Declared in the command_rec list with
239 * AP_INIT_TAKE23("directive", function, mconfig, where, help)
240 *
241 * static const char *handle_TAKE23(cmd_parms *cmd, void *mconfig,
242 * char *word1, char *word2, char *word3);
243 */
244
245 /*
246 * Command handler for a ITERATE directive.
247 * - Handler is called once for each of n arguments given to the directive.
248 * - word1 points to each argument in turn.
249 * Declared in the command_rec list with
250 * AP_INIT_ITERATE("directive", function, mconfig, where, help)
251 *
252 * static const char *handle_ITERATE(cmd_parms *cmd, void *mconfig,
253 * char *word1);
254 */
255
256 /*
257 * Command handler for a ITERATE2 directive.
258 * - Handler is called once for each of the second and subsequent arguments
259 * given to the directive.
260 * - word1 is the same for each call for a particular directive instance (the
261 * first argument).
262 * - word2 points to each of the second and subsequent arguments in turn.
263 * Declared in the command_rec list with
264 * AP_INIT_ITERATE2("directive", function, mconfig, where, help)
265 *
266 * static const char *handle_ITERATE2(cmd_parms *cmd, void *mconfig,
267 * char *word1, char *word2);
268 */
269
270 /*--------------------------------------------------------------------------*/
271 /* */
272 /* These routines are strictly internal to this module, and support its */
273 /* operation. They are not referenced by any external portion of the */
274 /* server. */
275 /* */
276 /*--------------------------------------------------------------------------*/
277
278 /*
279 * Locate our directory configuration record for the current request.
280 */
our_dconfig(const request_rec * r)281 static x_cfg *our_dconfig(const request_rec *r)
282 {
283 return (x_cfg *) ap_get_module_config(r->per_dir_config, &example_hooks_module);
284 }
285
286 /*
287 * The following utility routines are not used in the module. Don't
288 * compile them so -Wall doesn't complain about functions that are
289 * defined but not used.
290 */
291 #if 0
292 /*
293 * Locate our server configuration record for the specified server.
294 */
295 static x_cfg *our_sconfig(const server_rec *s)
296 {
297 return (x_cfg *) ap_get_module_config(s->module_config, &example_hooks_module);
298 }
299
300 /*
301 * Likewise for our configuration record for the specified request.
302 */
303 static x_cfg *our_rconfig(const request_rec *r)
304 {
305 return (x_cfg *) ap_get_module_config(r->request_config, &example_hooks_module);
306 }
307 #endif /* if 0 */
308
309 /*
310 * Likewise for our configuration record for a connection.
311 */
our_cconfig(const conn_rec * c)312 static x_cfg *our_cconfig(const conn_rec *c)
313 {
314 return (x_cfg *) ap_get_module_config(c->conn_config, &example_hooks_module);
315 }
316
317 /*
318 * You *could* change the following if you wanted to see the calling
319 * sequence reported in the server's error_log, but beware - almost all of
320 * these co-routines are called for every single request, and the impact
321 * on the size (and readability) of the error_log is considerable.
322 */
323 #ifndef EXAMPLE_LOG_EACH
324 #define EXAMPLE_LOG_EACH 0
325 #endif
326
327 #if EXAMPLE_LOG_EACH
example_log_each(apr_pool_t * p,server_rec * s,const char * note)328 static void example_log_each(apr_pool_t *p, server_rec *s, const char *note)
329 {
330 if (s != NULL) {
331 ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02991)
332 "mod_example_hooks: %s", note);
333 }
334 else {
335 apr_file_t *out = NULL;
336 apr_file_open_stderr(&out, p);
337 apr_file_printf(out, "mod_example_hooks traced in non-loggable "
338 "context: %s\n", note);
339 }
340 }
341 #endif
342
343 /*
344 * This utility routine traces the hooks called when the server starts up.
345 * It leaves a trace in a global variable, so it should not be called from
346 * a hook handler that runs in a multi-threaded situation.
347 */
348
trace_startup(apr_pool_t * p,server_rec * s,x_cfg * mconfig,const char * note)349 static void trace_startup(apr_pool_t *p, server_rec *s, x_cfg *mconfig,
350 const char *note)
351 {
352 const char *sofar;
353 char *where, *addon;
354
355 #if EXAMPLE_LOG_EACH
356 example_log_each(p, s, note);
357 #endif
358
359 /*
360 * If we weren't passed a configuration record, we can't figure out to
361 * what location this call applies. This only happens for co-routines
362 * that don't operate in a particular directory or server context. If we
363 * got a valid record, extract the location (directory or server) to which
364 * it applies.
365 */
366 where = (mconfig != NULL) ? mconfig->loc : "nowhere";
367 where = (where != NULL) ? where : "";
368
369 addon = apr_pstrcat(p,
370 " <li>\n"
371 " <dl>\n"
372 " <dt><samp>", note, "</samp></dt>\n"
373 " <dd><samp>[", where, "]</samp></dd>\n"
374 " </dl>\n"
375 " </li>\n",
376 NULL);
377
378 /*
379 * Make sure that we start with a valid string, even if we have never been
380 * called.
381 */
382 sofar = (trace == NULL) ? "" : trace;
383
384 trace = apr_pstrcat(p, sofar, addon, NULL);
385 }
386
387
388 /*
389 * This utility route traces the hooks called as a request is handled.
390 * It takes the current request as argument
391 */
392 #define TRACE_NOTE "example-hooks-trace"
393
trace_request(const request_rec * r,const char * note)394 static void trace_request(const request_rec *r, const char *note)
395 {
396 const char *trace_copy, *sofar;
397 char *addon, *where;
398 x_cfg *cfg;
399
400 #if EXAMPLE_LOG_EACH
401 example_log_each(r->pool, r->server, note);
402 #endif
403
404 if ((sofar = apr_table_get(r->notes, TRACE_NOTE)) == NULL) {
405 sofar = "";
406 }
407
408 cfg = our_dconfig(r);
409
410 where = (cfg != NULL) ? cfg->loc : "nowhere";
411 where = (where != NULL) ? where : "";
412
413 addon = apr_pstrcat(r->pool,
414 " <li>\n"
415 " <dl>\n"
416 " <dt><samp>", note, "</samp></dt>\n"
417 " <dd><samp>[", where, "]</samp></dd>\n"
418 " </dl>\n"
419 " </li>\n",
420 NULL);
421
422 trace_copy = apr_pstrcat(r->pool, sofar, addon, NULL);
423 apr_table_set(r->notes, TRACE_NOTE, trace_copy);
424 }
425
426 /*
427 * This utility routine traces the hooks called while processing a
428 * Connection. Its trace is kept in the pool notes of the pool associated
429 * with the Connection.
430 */
431
432 /*
433 * Key to get and set the userdata. We should be able to get away
434 * with a constant key, since in prefork mode the process will have
435 * the connection and its pool to itself entirely, and in
436 * multi-threaded mode each connection will have its own pool.
437 */
438 #define CONN_NOTE "example-hooks-connection"
439
trace_connection(conn_rec * c,const char * note)440 static void trace_connection(conn_rec *c, const char *note)
441 {
442 const char *trace_copy, *sofar;
443 char *addon, *where;
444 void *data;
445 x_cfg *cfg;
446
447 #if EXAMPLE_LOG_EACH
448 example_log_each(c->pool, c->base_server, note);
449 #endif
450
451 cfg = our_cconfig(c);
452
453 where = (cfg != NULL) ? cfg->loc : "nowhere";
454 where = (where != NULL) ? where : "";
455
456 addon = apr_pstrcat(c->pool,
457 " <li>\n"
458 " <dl>\n"
459 " <dt><samp>", note, "</samp></dt>\n"
460 " <dd><samp>[", where, "]</samp></dd>\n"
461 " </dl>\n"
462 " </li>\n",
463 NULL);
464
465 /* Find existing notes and copy */
466 apr_pool_userdata_get(&data, CONN_NOTE, c->pool);
467 sofar = (data == NULL) ? "" : (const char *) data;
468
469 /* Tack addon onto copy */
470 trace_copy = apr_pstrcat(c->pool, sofar, addon, NULL);
471
472 /*
473 * Stash copy back into pool notes. This call has a cleanup
474 * parameter, but we're not using it because the string has been
475 * allocated from that same pool. There is also an unused return
476 * value: we have nowhere to communicate any error that might
477 * occur, and will have to check for the existence of this data on
478 * the other end.
479 */
480 apr_pool_userdata_set((const void *) trace_copy, CONN_NOTE,
481 NULL, c->pool);
482 }
483
trace_nocontext(apr_pool_t * p,const char * file,int line,const char * note)484 static void trace_nocontext(apr_pool_t *p, const char *file, int line,
485 const char *note)
486 {
487 /*
488 * Since we have no request or connection to trace, or any idea
489 * from where this routine was called, there's really not much we
490 * can do. If we are not logging everything by way of the
491 * EXAMPLE_LOG_EACH constant, do nothing in this routine.
492 */
493
494 #ifdef EXAMPLE_LOG_EACH
495 ap_log_perror(file, line, APLOG_MODULE_INDEX, APLOG_NOTICE, 0, p, "%s", note);
496 #endif
497 }
498
499
500 /*--------------------------------------------------------------------------*/
501 /* We prototyped the various syntax for command handlers (routines that */
502 /* are called when the configuration parser detects a directive declared */
503 /* by our module) earlier. Now we actually declare a "real" routine that */
504 /* will be invoked by the parser when our "real" directive is */
505 /* encountered. */
506 /* */
507 /* If a command handler encounters a problem processing the directive, it */
508 /* signals this fact by returning a non-NULL pointer to a string */
509 /* describing the problem. */
510 /* */
511 /* The magic return value DECLINE_CMD is used to deal with directives */
512 /* that might be declared by multiple modules. If the command handler */
513 /* returns NULL, the directive was processed; if it returns DECLINE_CMD, */
514 /* the next module (if any) that declares the directive is given a chance */
515 /* at it. If it returns any other value, it's treated as the text of an */
516 /* error message. */
517 /*--------------------------------------------------------------------------*/
518 /*
519 * Command handler for the NO_ARGS "Example" directive. All we do is mark the
520 * call in the trace log, and flag the applicability of the directive to the
521 * current location in that location's configuration record.
522 */
cmd_example(cmd_parms * cmd,void * mconfig)523 static const char *cmd_example(cmd_parms *cmd, void *mconfig)
524 {
525 x_cfg *cfg = (x_cfg *) mconfig;
526
527 /*
528 * "Example Wuz Here"
529 */
530 cfg->local = 1;
531 trace_startup(cmd->pool, cmd->server, cfg, "cmd_example()");
532 return NULL;
533 }
534
535 /*
536 * This function gets called to create a per-directory configuration
537 * record. This will be called for the "default" server environment, and for
538 * each directory for which the parser finds any of our directives applicable.
539 * If a directory doesn't have any of our directives involved (i.e., they
540 * aren't in the .htaccess file, or a <Location>, <Directory>, or related
541 * block), this routine will *not* be called - the configuration for the
542 * closest ancestor is used.
543 *
544 * The return value is a pointer to the created module-specific
545 * structure.
546 */
x_create_dir_config(apr_pool_t * p,char * dirspec)547 static void *x_create_dir_config(apr_pool_t *p, char *dirspec)
548 {
549 x_cfg *cfg;
550 char *dname = dirspec;
551 char *note;
552
553 /*
554 * Allocate the space for our record from the pool supplied.
555 */
556 cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
557 /*
558 * Now fill in the defaults. If there are any `parent' configuration
559 * records, they'll get merged as part of a separate callback.
560 */
561 cfg->local = 0;
562 cfg->congenital = 0;
563 cfg->cmode = CONFIG_MODE_DIRECTORY;
564 /*
565 * Finally, add our trace to the callback list.
566 */
567 dname = (dname != NULL) ? dname : "";
568 cfg->loc = apr_pstrcat(p, "DIR(", dname, ")", NULL);
569 note = apr_psprintf(p, "x_create_dir_config(p == %pp, dirspec == %s)",
570 (void*) p, dirspec);
571 trace_startup(p, NULL, cfg, note);
572 return (void *) cfg;
573 }
574
575 /*
576 * This function gets called to merge two per-directory configuration
577 * records. This is typically done to cope with things like .htaccess files
578 * or <Location> directives for directories that are beneath one for which a
579 * configuration record was already created. The routine has the
580 * responsibility of creating a new record and merging the contents of the
581 * other two into it appropriately. If the module doesn't declare a merge
582 * routine, the record for the closest ancestor location (that has one) is
583 * used exclusively.
584 *
585 * The routine MUST NOT modify any of its arguments!
586 *
587 * The return value is a pointer to the created module-specific structure
588 * containing the merged values.
589 */
x_merge_dir_config(apr_pool_t * p,void * parent_conf,void * newloc_conf)590 static void *x_merge_dir_config(apr_pool_t *p, void *parent_conf,
591 void *newloc_conf)
592 {
593
594 x_cfg *merged_config = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
595 x_cfg *pconf = (x_cfg *) parent_conf;
596 x_cfg *nconf = (x_cfg *) newloc_conf;
597 char *note;
598
599 /*
600 * Some things get copied directly from the more-specific record, rather
601 * than getting merged.
602 */
603 merged_config->local = nconf->local;
604 merged_config->loc = apr_pstrdup(p, nconf->loc);
605 /*
606 * Others, like the setting of the `congenital' flag, get ORed in. The
607 * setting of that particular flag, for instance, is TRUE if it was ever
608 * true anywhere in the upstream configuration.
609 */
610 merged_config->congenital = (pconf->congenital | pconf->local);
611 /*
612 * If we're merging records for two different types of environment (server
613 * and directory), mark the new record appropriately. Otherwise, inherit
614 * the current value.
615 */
616 merged_config->cmode =
617 (pconf->cmode == nconf->cmode) ? pconf->cmode : CONFIG_MODE_COMBO;
618 /*
619 * Now just record our being called in the trace list. Include the
620 * locations we were asked to merge.
621 */
622 note = apr_psprintf(p, "x_merge_dir_config(p == %pp, parent_conf == "
623 "%pp, newloc_conf == %pp)", (void*) p,
624 (void*) parent_conf, (void*) newloc_conf);
625 trace_startup(p, NULL, merged_config, note);
626 return (void *) merged_config;
627 }
628
629 /*
630 * This function gets called to create a per-server configuration
631 * record. It will always be called for the "default" server.
632 *
633 * The return value is a pointer to the created module-specific
634 * structure.
635 */
x_create_server_config(apr_pool_t * p,server_rec * s)636 static void *x_create_server_config(apr_pool_t *p, server_rec *s)
637 {
638
639 x_cfg *cfg;
640 char *sname = s->server_hostname;
641
642 /*
643 * As with the x_create_dir_config() reoutine, we allocate and fill
644 * in an empty record.
645 */
646 cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
647 cfg->local = 0;
648 cfg->congenital = 0;
649 cfg->cmode = CONFIG_MODE_SERVER;
650 /*
651 * Note that we were called in the trace list.
652 */
653 sname = (sname != NULL) ? sname : "";
654 cfg->loc = apr_pstrcat(p, "SVR(", sname, ")", NULL);
655 trace_startup(p, s, cfg, "x_create_server_config()");
656 return (void *) cfg;
657 }
658
659 /*
660 * This function gets called to merge two per-server configuration
661 * records. This is typically done to cope with things like virtual hosts and
662 * the default server configuration The routine has the responsibility of
663 * creating a new record and merging the contents of the other two into it
664 * appropriately. If the module doesn't declare a merge routine, the more
665 * specific existing record is used exclusively.
666 *
667 * The routine MUST NOT modify any of its arguments!
668 *
669 * The return value is a pointer to the created module-specific structure
670 * containing the merged values.
671 */
x_merge_server_config(apr_pool_t * p,void * server1_conf,void * server2_conf)672 static void *x_merge_server_config(apr_pool_t *p, void *server1_conf,
673 void *server2_conf)
674 {
675
676 x_cfg *merged_config = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg));
677 x_cfg *s1conf = (x_cfg *) server1_conf;
678 x_cfg *s2conf = (x_cfg *) server2_conf;
679 char *note;
680
681 /*
682 * Our inheritance rules are our own, and part of our module's semantics.
683 * Basically, just note whence we came.
684 */
685 merged_config->cmode =
686 (s1conf->cmode == s2conf->cmode) ? s1conf->cmode : CONFIG_MODE_COMBO;
687 merged_config->local = s2conf->local;
688 merged_config->congenital = (s1conf->congenital | s1conf->local);
689 merged_config->loc = apr_pstrdup(p, s2conf->loc);
690 /*
691 * Trace our call, including what we were asked to merge.
692 */
693 note = apr_pstrcat(p, "x_merge_server_config(\"", s1conf->loc, "\",\"",
694 s2conf->loc, "\")", NULL);
695 trace_startup(p, NULL, merged_config, note);
696 return (void *) merged_config;
697 }
698
699
700 /*--------------------------------------------------------------------------*
701 * *
702 * Now let's declare routines for each of the callback hooks in order. *
703 * (That's the order in which they're listed in the callback list, *not *
704 * the order in which the server calls them! See the command_rec *
705 * declaration near the bottom of this file.) Note that these may be *
706 * called for situations that don't relate primarily to our function - in *
707 * other words, the fixup handler shouldn't assume that the request has *
708 * to do with "example_hooks" stuff. *
709 * *
710 * With the exception of the content handler, all of our routines will be *
711 * called for each request, unless an earlier handler from another module *
712 * aborted the sequence. *
713 * *
714 * There are three types of hooks (see include/ap_config.h): *
715 * *
716 * VOID : No return code, run all handlers declared by any module *
717 * RUN_FIRST : Run all handlers until one returns something other *
718 * than DECLINED. Hook runner result is result of last callback *
719 * RUN_ALL : Run all handlers until one returns something other than OK *
720 * or DECLINED. The hook runner returns that other value. If *
721 * all hooks run, the hook runner returns OK. *
722 * *
723 * Handlers that are declared as "int" can return the following: *
724 * *
725 * OK Handler accepted the request and did its thing with it. *
726 * DECLINED Handler took no action. *
727 * HTTP_mumble Handler looked at request and found it wanting. *
728 * *
729 * See include/httpd.h for a list of HTTP_mumble status codes. Handlers *
730 * that are not declared as int return a valid pointer, or NULL if they *
731 * DECLINE to handle their phase for that specific request. Exceptions, if *
732 * any, are noted with each routine. *
733 *--------------------------------------------------------------------------*/
734
735 /*
736 * This routine is called before the server processes the configuration
737 * files. There is no return value.
738 */
x_pre_config(apr_pool_t * pconf,apr_pool_t * plog,apr_pool_t * ptemp)739 static int x_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
740 apr_pool_t *ptemp)
741 {
742 /*
743 * Log the call and exit.
744 */
745 trace_startup(pconf, NULL, NULL, "x_pre_config()");
746 return OK;
747 }
748
749 /*
750 * This routine is called after the server processes the configuration
751 * files. At this point the module may review and adjust its configuration
752 * settings in relation to one another and report any problems. On restart,
753 * this routine will be called twice, once in the startup process (which
754 * exits shortly after this phase) and once in the running server process.
755 *
756 * The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
757 * server will still call any remaining modules with an handler for this
758 * phase.
759 */
x_check_config(apr_pool_t * pconf,apr_pool_t * plog,apr_pool_t * ptemp,server_rec * s)760 static int x_check_config(apr_pool_t *pconf, apr_pool_t *plog,
761 apr_pool_t *ptemp, server_rec *s)
762 {
763 /*
764 * Log the call and exit.
765 */
766 trace_startup(pconf, s, NULL, "x_check_config()");
767 return OK;
768 }
769
770 /*
771 * This routine is called when the -t command-line option is supplied.
772 * It executes only once, in the startup process, after the check_config
773 * phase and just before the process exits. At this point the module
774 * may output any information useful in configuration testing.
775 *
776 * This is a VOID hook: all defined handlers get called.
777 */
x_test_config(apr_pool_t * pconf,server_rec * s)778 static void x_test_config(apr_pool_t *pconf, server_rec *s)
779 {
780 apr_file_t *out = NULL;
781
782 apr_file_open_stderr(&out, pconf);
783
784 apr_file_printf(out, "Example module configuration test routine\n");
785
786 trace_startup(pconf, s, NULL, "x_test_config()");
787 }
788
789 /*
790 * This routine is called to perform any module-specific log file
791 * openings. It is invoked just before the post_config phase
792 *
793 * The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
794 * server will still call any remaining modules with an handler for this
795 * phase.
796 */
x_open_logs(apr_pool_t * pconf,apr_pool_t * plog,apr_pool_t * ptemp,server_rec * s)797 static int x_open_logs(apr_pool_t *pconf, apr_pool_t *plog,
798 apr_pool_t *ptemp, server_rec *s)
799 {
800 /*
801 * Log the call and exit.
802 */
803 trace_startup(pconf, s, NULL, "x_open_logs()");
804 return OK;
805 }
806
807 /*
808 * This routine is called after the server finishes the configuration
809 * process. At this point the module may review and adjust its configuration
810 * settings in relation to one another and report any problems. On restart,
811 * this routine will be called only once, in the running server process.
812 *
813 * The return value is OK, DECLINED, or HTTP_mumble. If we return OK, the
814 * server will still call any remaining modules with an handler for this
815 * phase.
816 */
x_post_config(apr_pool_t * pconf,apr_pool_t * plog,apr_pool_t * ptemp,server_rec * s)817 static int x_post_config(apr_pool_t *pconf, apr_pool_t *plog,
818 apr_pool_t *ptemp, server_rec *s)
819 {
820 /*
821 * Log the call and exit.
822 */
823 trace_startup(pconf, s, NULL, "x_post_config()");
824 return OK;
825 }
826
827 /*
828 * All our process-death routine does is add its trace to the log.
829 */
x_child_exit(void * data)830 static apr_status_t x_child_exit(void *data)
831 {
832 char *note;
833 server_rec *s = data;
834 char *sname = s->server_hostname;
835
836 /*
837 * The arbitrary text we add to our trace entry indicates for which server
838 * we're being called.
839 */
840 sname = (sname != NULL) ? sname : "";
841 note = apr_pstrcat(s->process->pool, "x_child_exit(", sname, ")", NULL);
842 trace_startup(s->process->pool, s, NULL, note);
843 return APR_SUCCESS;
844 }
845
846 /*
847 * All our process initialiser does is add its trace to the log.
848 *
849 * This is a VOID hook: all defined handlers get called.
850 */
x_child_init(apr_pool_t * p,server_rec * s)851 static void x_child_init(apr_pool_t *p, server_rec *s)
852 {
853 char *note;
854 char *sname = s->server_hostname;
855
856 /*
857 * The arbitrary text we add to our trace entry indicates for which server
858 * we're being called.
859 */
860 sname = (sname != NULL) ? sname : "";
861 note = apr_pstrcat(p, "x_child_init(", sname, ")", NULL);
862 trace_startup(p, s, NULL, note);
863
864 apr_pool_cleanup_register(p, s, x_child_exit, x_child_exit);
865 }
866
867 /*
868 * The hook runner for ap_hook_http_scheme is aliased to ap_http_scheme(),
869 * a routine that the core and other modules call when they need to know
870 * the URL scheme for the request. For instance, mod_ssl returns "https"
871 * if the server_rec associated with the request has SSL enabled.
872 *
873 * This hook was named 'ap_hook_http_method' in httpd 2.0.
874 *
875 * This is a RUN_FIRST hook: the first handler to return a non NULL
876 * value aborts the handler chain. The http_core module inserts a
877 * fallback handler (with APR_HOOK_REALLY_LAST preference) that returns
878 * "http".
879 */
x_http_scheme(const request_rec * r)880 static const char *x_http_scheme(const request_rec *r)
881 {
882 /*
883 * Log the call and exit.
884 */
885 trace_request(r, "x_http_scheme()");
886
887 /* We have no claims to make about the request scheme */
888 return NULL;
889 }
890
891 /*
892 * The runner for this hook is aliased to ap_default_port(), which the
893 * core and other modules call when they need to know the default port
894 * for a particular server. This is used for instance to omit the
895 * port number from a Redirect response Location header URL if the port
896 * number is equal to the default port for the service (like 80 for http).
897 *
898 * This is a RUN_FIRST hook: the first handler to return a non-zero
899 * value is the last one executed. The http_core module inserts a
900 * fallback handler (with APR_HOOK_REALLY_LAST order specifier) that
901 * returns 80.
902 */
x_default_port(const request_rec * r)903 static apr_port_t x_default_port(const request_rec *r)
904 {
905 /*
906 * Log the call and exit.
907 */
908 trace_request(r, "x_default_port()");
909 return 0;
910 }
911
912 /*
913 * This routine is called just before the handler gets invoked. It allows
914 * a module to insert a previously defined filter into the filter chain.
915 *
916 * No filter has been defined by this module, so we just log the call
917 * and exit.
918 *
919 * This is a VOID hook: all defined handlers get called.
920 */
x_insert_filter(request_rec * r)921 static void x_insert_filter(request_rec *r)
922 {
923 /*
924 * Log the call and exit.
925 */
926 trace_request(r, "x_insert_filter()");
927 }
928
929 /*
930 * This routine is called to insert a previously defined error filter into
931 * the filter chain as the request is being processed.
932 *
933 * For the purpose of this example, we don't have a filter to insert,
934 * so just add to the trace and exit.
935 *
936 * This is a VOID hook: all defined handlers get called.
937 */
x_insert_error_filter(request_rec * r)938 static void x_insert_error_filter(request_rec *r)
939 {
940 trace_request(r, "x_insert_error_filter()");
941 }
942
943 /*--------------------------------------------------------------------------*/
944 /* */
945 /* Now we declare our content handlers, which are invoked when the server */
946 /* encounters a document which our module is supposed to have a chance to */
947 /* see. (See mod_mime's SetHandler and AddHandler directives, and the */
948 /* mod_info and mod_status examples, for more details.) */
949 /* */
950 /* Since content handlers are dumping data directly into the connection */
951 /* (using the r*() routines, such as rputs() and rprintf()) without */
952 /* intervention by other parts of the server, they need to make */
953 /* sure any accumulated HTTP headers are sent first. This is done by */
954 /* calling send_http_header(). Otherwise, no header will be sent at all, */
955 /* and the output sent to the client will actually be HTTP-uncompliant. */
956 /*--------------------------------------------------------------------------*/
957 /*
958 * Sample content handler. All this does is display the call list that has
959 * been built up so far.
960 *
961 * This routine gets called for every request, unless another handler earlier
962 * in the callback chain has already handled the request. It is up to us to
963 * test the request_rec->handler field and see whether we are meant to handle
964 * this request.
965 *
966 * The content handler gets to write directly to the client using calls like
967 * ap_rputs() and ap_rprintf()
968 *
969 * This is a RUN_FIRST hook.
970 */
x_handler(request_rec * r)971 static int x_handler(request_rec *r)
972 {
973 x_cfg *dcfg;
974 char *note;
975 void *conn_data;
976 apr_status_t status;
977
978 dcfg = our_dconfig(r);
979 /*
980 * Add our trace to the log, and whether we get to write
981 * content for this request.
982 */
983 note = apr_pstrcat(r->pool, "x_handler(), handler is \"",
984 r->handler, "\"", NULL);
985 trace_request(r, note);
986
987 /* If it's not for us, get out as soon as possible. */
988 if (strcmp(r->handler, "example-hooks-handler")) {
989 return DECLINED;
990 }
991
992 /*
993 * Set the Content-type header. Note that we do not actually have to send
994 * the headers: this is done by the http core.
995 */
996 ap_set_content_type(r, "text/html");
997 /*
998 * If we're only supposed to send header information (HEAD request), we're
999 * already there.
1000 */
1001 if (r->header_only) {
1002 return OK;
1003 }
1004
1005 /*
1006 * Now send our actual output. Since we tagged this as being
1007 * "text/html", we need to embed any HTML.
1008 */
1009 ap_rputs(DOCTYPE_HTML_3_2, r);
1010 ap_rputs("<HTML>\n", r);
1011 ap_rputs(" <HEAD>\n", r);
1012 ap_rputs(" <TITLE>mod_example_hooks Module Content-Handler Output\n", r);
1013 ap_rputs(" </TITLE>\n", r);
1014 ap_rputs(" </HEAD>\n", r);
1015 ap_rputs(" <BODY>\n", r);
1016 ap_rputs(" <H1><SAMP>mod_example_hooks</SAMP> Module Content-Handler Output\n", r);
1017 ap_rputs(" </H1>\n", r);
1018 ap_rputs(" <P>\n", r);
1019 ap_rprintf(r, " Apache HTTP Server version: \"%s\"\n",
1020 ap_get_server_banner());
1021 ap_rputs(" <BR>\n", r);
1022 ap_rprintf(r, " Server built: \"%s\"\n", ap_get_server_built());
1023 ap_rputs(" </P>\n", r);
1024 ap_rputs(" <P>\n", r);
1025 ap_rputs(" The format for the callback trace is:\n", r);
1026 ap_rputs(" </P>\n", r);
1027 ap_rputs(" <DL>\n", r);
1028 ap_rputs(" <DT><EM>n</EM>.<SAMP><routine-name>", r);
1029 ap_rputs("(<routine-data>)</SAMP>\n", r);
1030 ap_rputs(" </DT>\n", r);
1031 ap_rputs(" <DD><SAMP>[<applies-to>]</SAMP>\n", r);
1032 ap_rputs(" </DD>\n", r);
1033 ap_rputs(" </DL>\n", r);
1034 ap_rputs(" <P>\n", r);
1035 ap_rputs(" The <SAMP><routine-data></SAMP> is supplied by\n", r);
1036 ap_rputs(" the routine when it requests the trace,\n", r);
1037 ap_rputs(" and the <SAMP><applies-to></SAMP> is extracted\n", r);
1038 ap_rputs(" from the configuration record at the time of the trace.\n", r);
1039 ap_rputs(" <STRONG>SVR()</STRONG> indicates a server environment\n", r);
1040 ap_rputs(" (blank means the main or default server, otherwise it's\n", r);
1041 ap_rputs(" the name of the VirtualHost); <STRONG>DIR()</STRONG>\n", r);
1042 ap_rputs(" indicates a location in the URL or filesystem\n", r);
1043 ap_rputs(" namespace.\n", r);
1044 ap_rputs(" </P>\n", r);
1045 ap_rprintf(r, " <H2>Startup callbacks so far:</H2>\n <OL>\n%s </OL>\n",
1046 trace);
1047 ap_rputs(" <H2>Connection-specific callbacks so far:</H2>\n", r);
1048
1049 status = apr_pool_userdata_get(&conn_data, CONN_NOTE,
1050 r->connection->pool);
1051 if ((status == APR_SUCCESS) && conn_data) {
1052 ap_rprintf(r, " <OL>\n%s </OL>\n", (char *) conn_data);
1053 }
1054 else {
1055 ap_rputs(" <P>No connection-specific callback information was "
1056 "retrieved.</P>\n", r);
1057 }
1058
1059 ap_rputs(" <H2>Request-specific callbacks so far:</H2>\n", r);
1060 ap_rprintf(r, " <OL>\n%s </OL>\n", apr_table_get(r->notes, TRACE_NOTE));
1061 ap_rputs(" <H2>Environment for <EM>this</EM> call:</H2>\n", r);
1062 ap_rputs(" <UL>\n", r);
1063 ap_rprintf(r, " <LI>Applies-to: <SAMP>%s</SAMP>\n </LI>\n", dcfg->loc);
1064 ap_rprintf(r, " <LI>\"Example\" directive declared here: %s\n </LI>\n",
1065 (dcfg->local ? "YES" : "NO"));
1066 ap_rprintf(r, " <LI>\"Example\" inherited: %s\n </LI>\n",
1067 (dcfg->congenital ? "YES" : "NO"));
1068 ap_rputs(" </UL>\n", r);
1069 ap_rputs(" </BODY>\n", r);
1070 ap_rputs("</HTML>\n", r);
1071 /*
1072 * We're all done, so cancel the timeout we set. Since this is probably
1073 * the end of the request we *could* assume this would be done during
1074 * post-processing - but it's possible that another handler might be
1075 * called and inherit our outstanding timer. Not good; to each its own.
1076 */
1077 /*
1078 * We did what we wanted to do, so tell the rest of the server we
1079 * succeeded.
1080 */
1081 return OK;
1082 }
1083
1084 /*
1085 * The quick_handler hook presents modules with a very powerful opportunity to
1086 * serve their content in a very early request phase. Note that this handler
1087 * can not serve any requests from the file system because hooks like
1088 * map_to_storage have not run. The quick_handler hook also runs before any
1089 * authentication and access control.
1090 *
1091 * This hook is used by mod_cache to serve cached content.
1092 *
1093 * This is a RUN_FIRST hook. Return OK if you have served the request,
1094 * DECLINED if you want processing to continue, or a HTTP_* error code to stop
1095 * processing the request.
1096 */
x_quick_handler(request_rec * r,int lookup_uri)1097 static int x_quick_handler(request_rec *r, int lookup_uri)
1098 {
1099 /*
1100 * Log the call and exit.
1101 */
1102 trace_request(r, "x_quick_handler()");
1103 return DECLINED;
1104 }
1105
1106 /*
1107 * This routine is called just after the server accepts the connection,
1108 * but before it is handed off to a protocol module to be served. The point
1109 * of this hook is to allow modules an opportunity to modify the connection
1110 * as soon as possible. The core server uses this phase to setup the
1111 * connection record based on the type of connection that is being used.
1112 *
1113 * This is a RUN_ALL hook.
1114 */
x_pre_connection(conn_rec * c,void * csd)1115 static int x_pre_connection(conn_rec *c, void *csd)
1116 {
1117 char *note;
1118
1119 /*
1120 * Log the call and exit.
1121 */
1122 note = apr_psprintf(c->pool, "x_pre_connection(c = %pp, p = %pp)",
1123 (void*) c, (void*) c->pool);
1124 trace_connection(c, note);
1125
1126 return OK;
1127 }
1128
1129 /* This routine is used to actually process the connection that was received.
1130 * Only protocol modules should implement this hook, as it gives them an
1131 * opportunity to replace the standard HTTP processing with processing for
1132 * some other protocol. Both echo and POP3 modules are available as
1133 * examples.
1134 *
1135 * This is a RUN_FIRST hook.
1136 */
x_process_connection(conn_rec * c)1137 static int x_process_connection(conn_rec *c)
1138 {
1139 trace_connection(c, "x_process_connection()");
1140 return DECLINED;
1141 }
1142
1143 /*
1144 * This routine is called after the request has been read but before any other
1145 * phases have been processed. This allows us to make decisions based upon
1146 * the input header fields.
1147 *
1148 * This is a HOOK_VOID hook.
1149 */
x_pre_read_request(request_rec * r,conn_rec * c)1150 static void x_pre_read_request(request_rec *r, conn_rec *c)
1151 {
1152 /*
1153 * We don't actually *do* anything here, except note the fact that we were
1154 * called.
1155 */
1156 trace_request(r, "x_pre_read_request()");
1157 }
1158
1159 /*
1160 * This routine is called after the request has been read but before any other
1161 * phases have been processed. This allows us to make decisions based upon
1162 * the input header fields.
1163 *
1164 * This is a RUN_ALL hook.
1165 */
x_post_read_request(request_rec * r)1166 static int x_post_read_request(request_rec *r)
1167 {
1168 /*
1169 * We don't actually *do* anything here, except note the fact that we were
1170 * called.
1171 */
1172 trace_request(r, "x_post_read_request()");
1173 return DECLINED;
1174 }
1175
1176 /*
1177 * This routine gives our module an opportunity to translate the URI into an
1178 * actual filename, before URL decoding happens.
1179 *
1180 * This is a RUN_FIRST hook.
1181 */
x_pre_translate_name(request_rec * r)1182 static int x_pre_translate_name(request_rec *r)
1183 {
1184 /*
1185 * We don't actually *do* anything here, except note the fact that we were
1186 * called.
1187 */
1188 trace_request(r, "x_pre_translate_name()");
1189 return DECLINED;
1190 }
1191
1192 /*
1193 * This routine gives our module an opportunity to translate the URI into an
1194 * actual filename. If we don't do anything special, the server's default
1195 * rules (Alias directives and the like) will continue to be followed.
1196 *
1197 * This is a RUN_FIRST hook.
1198 */
x_translate_name(request_rec * r)1199 static int x_translate_name(request_rec *r)
1200 {
1201 /*
1202 * We don't actually *do* anything here, except note the fact that we were
1203 * called.
1204 */
1205 trace_request(r, "x_translate_name()");
1206 return DECLINED;
1207 }
1208
1209 /*
1210 * This routine maps r->filename to a physical file on disk. Useful for
1211 * overriding default core behavior, including skipping mapping for
1212 * requests that are not file based.
1213 *
1214 * This is a RUN_FIRST hook.
1215 */
x_map_to_storage(request_rec * r)1216 static int x_map_to_storage(request_rec *r)
1217 {
1218 /*
1219 * We don't actually *do* anything here, except note the fact that we were
1220 * called.
1221 */
1222 trace_request(r, "x_map_to_storage()");
1223 return DECLINED;
1224 }
1225
1226 /*
1227 * this routine gives our module another chance to examine the request
1228 * headers and to take special action. This is the first phase whose
1229 * hooks' configuration directives can appear inside the <Directory>
1230 * and similar sections, because at this stage the URI has been mapped
1231 * to the filename. For example this phase can be used to block evil
1232 * clients, while little resources were wasted on these.
1233 *
1234 * This is a RUN_ALL hook.
1235 */
x_header_parser(request_rec * r)1236 static int x_header_parser(request_rec *r)
1237 {
1238 /*
1239 * We don't actually *do* anything here, except note the fact that we were
1240 * called.
1241 */
1242 trace_request(r, "x_header_parser()");
1243 return DECLINED;
1244 }
1245
1246
1247 /*
1248 * This routine is called to check for any module-specific restrictions placed
1249 * upon the requested resource. (See the mod_access_compat module for an
1250 * example.)
1251 *
1252 * This is a RUN_ALL hook. The first handler to return a status other than OK
1253 * or DECLINED (for instance, HTTP_FORBIDDEN) aborts the callback chain.
1254 */
x_check_access(request_rec * r)1255 static int x_check_access(request_rec *r)
1256 {
1257 trace_request(r, "x_check_access()");
1258 return DECLINED;
1259 }
1260
1261 /*
1262 * This routine is called to check the authentication information sent with
1263 * the request (such as looking up the user in a database and verifying that
1264 * the [encrypted] password sent matches the one in the database).
1265 *
1266 * This is a RUN_FIRST hook. The return value is OK, DECLINED, or some
1267 * HTTP_mumble error (typically HTTP_UNAUTHORIZED).
1268 */
x_check_authn(request_rec * r)1269 static int x_check_authn(request_rec *r)
1270 {
1271 /*
1272 * Don't do anything except log the call.
1273 */
1274 trace_request(r, "x_check_authn()");
1275 return DECLINED;
1276 }
1277
1278 /*
1279 * This routine is called to check to see if the resource being requested
1280 * requires authorisation.
1281 *
1282 * This is a RUN_FIRST hook. The return value is OK, DECLINED, or
1283 * HTTP_mumble. If we return OK, no other modules are called during this
1284 * phase.
1285 *
1286 * If *all* modules return DECLINED, the request is aborted with a server
1287 * error.
1288 */
x_check_authz(request_rec * r)1289 static int x_check_authz(request_rec *r)
1290 {
1291 /*
1292 * Log the call and return OK, or access will be denied (even though we
1293 * didn't actually do anything).
1294 */
1295 trace_request(r, "x_check_authz()");
1296 return DECLINED;
1297 }
1298
1299 /*
1300 * This routine is called to determine and/or set the various document type
1301 * information bits, like Content-type (via r->content_type), language, et
1302 * cetera.
1303 *
1304 * This is a RUN_FIRST hook.
1305 */
x_type_checker(request_rec * r)1306 static int x_type_checker(request_rec *r)
1307 {
1308 /*
1309 * Log the call, but don't do anything else - and report truthfully that
1310 * we didn't do anything.
1311 */
1312 trace_request(r, "x_type_checker()");
1313 return DECLINED;
1314 }
1315
1316 /*
1317 * This routine is called to perform any module-specific fixing of header
1318 * fields, et cetera. It is invoked just before any content-handler.
1319 *
1320 * This is a RUN_ALL HOOK.
1321 */
x_fixups(request_rec * r)1322 static int x_fixups(request_rec *r)
1323 {
1324 /*
1325 * Log the call and exit.
1326 */
1327 trace_request(r, "x_fixups()");
1328 return DECLINED;
1329 }
1330
1331 /*
1332 * This routine is called to perform any module-specific logging activities
1333 * over and above the normal server things.
1334 *
1335 * This is a RUN_ALL hook.
1336 */
x_log_transaction(request_rec * r)1337 static int x_log_transaction(request_rec *r)
1338 {
1339 trace_request(r, "x_log_transaction()");
1340 return DECLINED;
1341 }
1342
1343 #ifdef HAVE_UNIX_SUEXEC
1344
1345 /*
1346 * This routine is called to find out under which user id to run suexec
1347 * Unless our module runs CGI programs, there is no reason for us to
1348 * mess with this information.
1349 *
1350 * This is a RUN_FIRST hook. The return value is a pointer to an
1351 * ap_unix_identity_t or NULL.
1352 */
x_get_suexec_identity(const request_rec * r)1353 static ap_unix_identity_t *x_get_suexec_identity(const request_rec *r)
1354 {
1355 trace_request(r, "x_get_suexec_identity()");
1356 return NULL;
1357 }
1358 #endif
1359
1360 /*
1361 * This routine is called to create a connection. This hook is implemented
1362 * by the Apache core: there is no known reason a module should override
1363 * it.
1364 *
1365 * This is a RUN_FIRST hook.
1366 *
1367 * Return NULL to decline, a valid conn_rec pointer to accept.
1368 */
x_create_connection(apr_pool_t * p,server_rec * server,apr_socket_t * csd,long conn_id,void * sbh,apr_bucket_alloc_t * alloc)1369 static conn_rec *x_create_connection(apr_pool_t *p, server_rec *server,
1370 apr_socket_t *csd, long conn_id,
1371 void *sbh, apr_bucket_alloc_t *alloc)
1372 {
1373 trace_nocontext(p, __FILE__, __LINE__, "x_create_connection()");
1374 return NULL;
1375 }
1376
1377 /*
1378 * This hook is defined in server/core.c, but it is not actually called
1379 * or documented.
1380 *
1381 * This is a RUN_ALL hook.
1382 */
x_get_mgmt_items(apr_pool_t * p,const char * val,apr_hash_t * ht)1383 static int x_get_mgmt_items(apr_pool_t *p, const char *val, apr_hash_t *ht)
1384 {
1385 /* We have nothing to do here but trace the call, and no context
1386 * in which to trace it.
1387 */
1388 trace_nocontext(p, __FILE__, __LINE__, "x_check_config()");
1389 return DECLINED;
1390 }
1391
1392 /*
1393 * This routine gets called shortly after the request_rec structure
1394 * is created. It provides the opportunity to manipulae the request
1395 * at a very early stage.
1396 *
1397 * This is a RUN_ALL hook.
1398 */
x_create_request(request_rec * r)1399 static int x_create_request(request_rec *r)
1400 {
1401 /*
1402 * We have a request_rec, but it is not filled in enough to give
1403 * us a usable configuration. So, add a trace without context.
1404 */
1405 trace_nocontext( r->pool, __FILE__, __LINE__, "x_create_request()");
1406 return DECLINED;
1407 }
1408
1409 /*
1410 * This routine gets called during the startup of the MPM.
1411 * No known existing module implements this hook.
1412 *
1413 * This is a RUN_ALL hook.
1414 */
x_pre_mpm(apr_pool_t * p,ap_scoreboard_e sb_type)1415 static int x_pre_mpm(apr_pool_t *p, ap_scoreboard_e sb_type)
1416 {
1417 trace_nocontext(p, __FILE__, __LINE__, "x_pre_mpm()");
1418 return DECLINED;
1419 }
1420
1421 /*
1422 * This hook gets run periodically by a maintenance function inside
1423 * the MPM. Its exact purpose is unknown and undocumented at this time.
1424 *
1425 * This is a RUN_ALL hook.
1426 */
x_monitor(apr_pool_t * p,server_rec * s)1427 static int x_monitor(apr_pool_t *p, server_rec *s)
1428 {
1429 trace_nocontext(p, __FILE__, __LINE__, "x_monitor()");
1430 return DECLINED;
1431 }
1432
1433 /*--------------------------------------------------------------------------*/
1434 /* */
1435 /* Which functions are responsible for which hooks in the server. */
1436 /* */
1437 /*--------------------------------------------------------------------------*/
1438 /*
1439 * Each function our module provides to handle a particular hook is
1440 * specified here. The functions are registered using
1441 * ap_hook_foo(name, predecessors, successors, position)
1442 * where foo is the name of the hook.
1443 *
1444 * The args are as follows:
1445 * name -> the name of the function to call.
1446 * predecessors -> a list of modules whose calls to this hook must be
1447 * invoked before this module.
1448 * successors -> a list of modules whose calls to this hook must be
1449 * invoked after this module.
1450 * position -> The relative position of this module. One of
1451 * APR_HOOK_FIRST, APR_HOOK_MIDDLE, or APR_HOOK_LAST.
1452 * Most modules will use APR_HOOK_MIDDLE. If multiple
1453 * modules use the same relative position, Apache will
1454 * determine which to call first.
1455 * If your module relies on another module to run first,
1456 * or another module running after yours, use the
1457 * predecessors and/or successors.
1458 *
1459 * The number in brackets indicates the order in which the routine is called
1460 * during request processing. Note that not all routines are necessarily
1461 * called (such as if a resource doesn't have access restrictions).
1462 * The actual delivery of content to the browser [9] is not handled by
1463 * a hook; see the handler declarations below.
1464 */
x_register_hooks(apr_pool_t * p)1465 static void x_register_hooks(apr_pool_t *p)
1466 {
1467 trace = NULL;
1468 ap_hook_pre_config(x_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
1469 ap_hook_check_config(x_check_config, NULL, NULL, APR_HOOK_MIDDLE);
1470 ap_hook_test_config(x_test_config, NULL, NULL, APR_HOOK_MIDDLE);
1471 ap_hook_open_logs(x_open_logs, NULL, NULL, APR_HOOK_MIDDLE);
1472 ap_hook_post_config(x_post_config, NULL, NULL, APR_HOOK_MIDDLE);
1473 ap_hook_child_init(x_child_init, NULL, NULL, APR_HOOK_MIDDLE);
1474 ap_hook_handler(x_handler, NULL, NULL, APR_HOOK_MIDDLE);
1475 ap_hook_quick_handler(x_quick_handler, NULL, NULL, APR_HOOK_MIDDLE);
1476 ap_hook_pre_connection(x_pre_connection, NULL, NULL, APR_HOOK_MIDDLE);
1477 ap_hook_process_connection(x_process_connection, NULL, NULL, APR_HOOK_MIDDLE);
1478 ap_hook_pre_read_request(x_pre_read_request, NULL, NULL,
1479 APR_HOOK_MIDDLE);
1480 /* [1] post read_request handling */
1481 ap_hook_post_read_request(x_post_read_request, NULL, NULL,
1482 APR_HOOK_MIDDLE);
1483 ap_hook_log_transaction(x_log_transaction, NULL, NULL, APR_HOOK_MIDDLE);
1484 ap_hook_http_scheme(x_http_scheme, NULL, NULL, APR_HOOK_MIDDLE);
1485 ap_hook_default_port(x_default_port, NULL, NULL, APR_HOOK_MIDDLE);
1486 ap_hook_pre_translate_name(x_pre_translate_name, NULL, NULL, APR_HOOK_MIDDLE);
1487 ap_hook_translate_name(x_translate_name, NULL, NULL, APR_HOOK_MIDDLE);
1488 ap_hook_map_to_storage(x_map_to_storage, NULL,NULL, APR_HOOK_MIDDLE);
1489 ap_hook_header_parser(x_header_parser, NULL, NULL, APR_HOOK_MIDDLE);
1490 ap_hook_fixups(x_fixups, NULL, NULL, APR_HOOK_MIDDLE);
1491 ap_hook_type_checker(x_type_checker, NULL, NULL, APR_HOOK_MIDDLE);
1492 ap_hook_check_access(x_check_access, NULL, NULL, APR_HOOK_MIDDLE,
1493 AP_AUTH_INTERNAL_PER_CONF);
1494 ap_hook_check_authn(x_check_authn, NULL, NULL, APR_HOOK_MIDDLE,
1495 AP_AUTH_INTERNAL_PER_CONF);
1496 ap_hook_check_authz(x_check_authz, NULL, NULL, APR_HOOK_MIDDLE,
1497 AP_AUTH_INTERNAL_PER_CONF);
1498 ap_hook_insert_filter(x_insert_filter, NULL, NULL, APR_HOOK_MIDDLE);
1499 ap_hook_insert_error_filter(x_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
1500 #ifdef HAVE_UNIX_SUEXEC
1501 ap_hook_get_suexec_identity(x_get_suexec_identity, NULL, NULL, APR_HOOK_MIDDLE);
1502 #endif
1503 ap_hook_create_connection(x_create_connection, NULL, NULL, APR_HOOK_MIDDLE);
1504 ap_hook_get_mgmt_items(x_get_mgmt_items, NULL, NULL, APR_HOOK_MIDDLE);
1505 ap_hook_create_request(x_create_request, NULL, NULL, APR_HOOK_MIDDLE);
1506 ap_hook_pre_mpm(x_pre_mpm, NULL, NULL, APR_HOOK_MIDDLE);
1507 ap_hook_monitor(x_monitor, NULL, NULL, APR_HOOK_MIDDLE);
1508 }
1509
1510 /*--------------------------------------------------------------------------*/
1511 /* */
1512 /* All of the routines have been declared now. Here's the list of */
1513 /* directives specific to our module, and information about where they */
1514 /* may appear and how the command parser should pass them to us for */
1515 /* processing. Note that care must be taken to ensure that there are NO */
1516 /* collisions of directive names between modules. */
1517 /* */
1518 /*--------------------------------------------------------------------------*/
1519 /*
1520 * List of directives specific to our module.
1521 */
1522 static const command_rec x_cmds[] =
1523 {
1524 AP_INIT_NO_ARGS(
1525 "Example", /* directive name */
1526 cmd_example, /* config action routine */
1527 NULL, /* argument to include in call */
1528 OR_OPTIONS, /* where available */
1529 "Example directive - no arguments" /* directive description */
1530 ),
1531 {NULL}
1532 };
1533 /*--------------------------------------------------------------------------*/
1534 /* */
1535 /* Finally, the list of callback routines and data structures that provide */
1536 /* the static hooks into our module from the other parts of the server. */
1537 /* */
1538 /*--------------------------------------------------------------------------*/
1539 /*
1540 * Module definition for configuration. If a particular callback is not
1541 * needed, replace its routine name below with the word NULL.
1542 */
1543 AP_DECLARE_MODULE(example_hooks) =
1544 {
1545 STANDARD20_MODULE_STUFF,
1546 x_create_dir_config, /* per-directory config creator */
1547 x_merge_dir_config, /* dir config merger */
1548 x_create_server_config, /* server config creator */
1549 x_merge_server_config, /* server config merger */
1550 x_cmds, /* command table */
1551 x_register_hooks, /* set up other request processing hooks */
1552 };
1553