/src/proftpd/src/event.c

Source (jump to first uncovered line)
/*
 * ProFTPD - FTP server daemon
 * Copyright (c) 2003-2020 The ProFTPD Project team
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
 *
 * As a special exemption, The ProFTPD Project team and other respective
 * copyright holders give permission to link this program with OpenSSL, and
 * distribute the resulting executable, without including the source code for
 * OpenSSL in the source distribution.
 */

/* Event management code */

#include "conf.h"

/* Note: as more events are added, and as this API grows more and more used
 * by the core code, look into using a different ADT for storage/retrieval
 * of these objects, such as hash tables.
 */

struct event_handler {
  struct event_handler *next, *prev;
  module *module;
  void (*cb)(const void *, void *);
  void *user_data;
  unsigned long flags;
};

struct event_list {
  struct event_list *next;
  pool *pool;
  const char *event;
  size_t event_len;
  struct event_handler *handlers;
};

static pool *event_pool = NULL;
static struct event_list *events = NULL;

static const char *curr_event = NULL;
static struct event_list *curr_evl = NULL;
static struct event_handler *curr_evh = NULL;

/* Certain events are NOT logged via Trace logging (in order to prevent
 * event/trace loops).
 */
static const char *untraced_events[] = {
  PR_LOG_NAME_UNSPEC,
  PR_LOG_NAME_XFERLOG,
  PR_LOG_NAME_SYSLOG,
  PR_LOG_NAME_SYSTEMLOG,
  PR_LOG_NAME_EXTLOG,
  PR_LOG_NAME_TRACELOG,
  NULL
};

#define PR_EVENT_FL_UNTRACED    0x001

static const char *trace_channel = "event";

#define EVENT_POOL_SZ 256

static void event_cleanup_cb(void *user_data) {
  event_pool = NULL;
  events = NULL;

  curr_event = NULL;
  curr_evl = NULL;
  curr_evh = NULL;
}

int pr_event_register(module *m, const char *event,
    void (*cb)(const void *, void *), void *user_data) {
  register unsigned int i;
  struct event_handler *evh;
  struct event_list *evl;
  pool *evl_pool;
  unsigned long flags = 0;

  if (event == NULL ||
      cb == NULL) {
    errno = EINVAL;
    return -1;
  }

  if (event_pool == NULL) {
    event_pool = make_sub_pool(permanent_pool);
    pr_pool_tag(event_pool, "Event Pool");

    register_cleanup2(event_pool, NULL, event_cleanup_cb);
  }

  pr_trace_msg(trace_channel, 3,
    "module '%s' (%p) registering handler for event '%s' (at %p)",
    m ? m->name : "(none)", m, event, cb);

  evh = pcalloc(event_pool, sizeof(struct event_handler));

  evh->module = m;
  evh->cb = cb;
  evh->user_data = user_data;

  /* Is this an untraced event? */
  for (i = 0; untraced_events[i] != NULL; i++) {
    if (strcmp(event, untraced_events[i]) == 0) {
      flags = PR_EVENT_FL_UNTRACED;
      break;
    }
  }

  evh->flags = flags;

  /* Scan the currently registered lists, looking for where to add this
   * registration.
   */

  for (evl = events; evl; evl = evl->next) {
    if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
      struct event_handler *evhi, *evhl = NULL;

      evhi = evl->handlers;
      if (evhi) {
        /* Make sure this event handler is added to the START of the list,
         * in order to preserve module load order handling of events (i.e.
         * last module loaded, first module handled).  The exception to this
         * rule are core callbacks (i.e. where m == NULL); these will always
         * be invoked last.
         *
         * Before that, though, check for duplicate registration/subscription.
         */
        while (evhi) {
          pr_signals_handle();

          if (evhi->cb == evh->cb) {
            /* Duplicate callback */
            errno = EEXIST;
            return -1;
          }

          evhl = evhi;

          if (evhi->next == NULL) {
            break;
          }

          evhi = evhi->next;
        }

        if (evh->module != NULL) {
          if (evl->handlers != NULL) {
            evl->handlers->prev = evh;
          }

          evh->next = evl->handlers;
          evl->handlers = evh;

        } else {
          /* Core event listeners go at the end. */
          evhl->next = evh;
          evh->prev = evhl;
        }

      } else {
        evl->handlers = evh;
      }

      /* All done */
      return 0;
    }
  }

  evl_pool = pr_pool_create_sz(event_pool, EVENT_POOL_SZ);
  pr_pool_tag(evl_pool, "Event listener list pool");

  evl = pcalloc(evl_pool, sizeof(struct event_list));
  evl->pool = evl_pool;
  evl->event = pstrdup(evl->pool, event);
  evl->event_len = strlen(evl->event);
  evl->handlers = evh;
  evl->next = events;

  events = evl;

  /* Clear any cached data. */
  curr_event = NULL;
  curr_evl = NULL;
  curr_evh = NULL;

  return 0;
}

int pr_event_unregister(module *m, const char *event,
    void (*cb)(const void *, void *)) {
  struct event_list *evl;
  int unregistered = FALSE;

  if (events == NULL) {
    return 0;
  }

  pr_trace_msg(trace_channel, 3,
    "module '%s' (%p) unregistering handler for event '%s'",
    m ? m->name : "(none)", m, event ? event : "(all)");

  /* For now, simply remove the event_handler entry for this callback.  In
   * the future, add a static counter, and churn the event pool after a
   * certain number of unregistrations, so that the memory pool doesn't
   * grow unnecessarily.
   */

  for (evl = events; evl; evl = evl->next) {
    pr_signals_handle();

    if (event == NULL ||
        strncmp(evl->event, event, evl->event_len + 1) == 0) {
      struct event_handler *evh;

      /* If there are no handlers for this event, there is nothing to
       * unregister.  Skip on to the next list.
       */
      if (evl->handlers == NULL) {
        continue;
      }

      for (evh = evl->handlers; evh;) {

        if ((m == NULL || evh->module == m) &&
            (cb == NULL || evh->cb == cb)) {
          struct event_handler *tmp = evh->next;

          if (evh->next) {
            evh->next->prev = evh->prev;
          }

          if (evh->prev) {
            evh->prev->next = evh->next;

          } else {
            /* This is the head of the list. */
            evl->handlers = evh->next;
          }

          evh->module = NULL;
          evh = tmp;
          unregistered = TRUE;

        } else {
          evh = evh->next;
        }
      }
    }
  }

  /* Clear any cached data. */
  curr_event = NULL;
  curr_evl = NULL;
  curr_evh = NULL;

  if (!unregistered) {
    errno = ENOENT;
    return -1;
  }

  return 0;
}

int pr_event_listening(const char *event) {
  struct event_list *evl;
  int count = 0;

  if (event == NULL) {
    errno = EINVAL;
    return -1;
  }

  if (events == NULL) {
    /* No registered listeners at all. */
    return 0;
  }

  /* Lookup callbacks for this event. */
  for (evl = events; evl; evl = evl->next) {

    if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
      struct event_handler *evh;

      /* If there are no registered callbacks for this event, be done. */
      if (evl->handlers == NULL) {
        return 0;
      }

      for (evh = evl->handlers; evh; evh = evh->next) {
        count++;
      }

      break;
    }
  }

  return count;
}

void pr_event_generate(const char *event, const void *event_data) {
  int use_cache = FALSE;
  struct event_list *evl;

  if (event == NULL) {
    return;
  }

  /* If there are no registered callbacks, be done. */
  if (events == NULL) {
    return;
  }

  /* If there is a cached event, see if the given event matches. */
  if (curr_event != NULL &&
      strcmp(curr_event, event) == 0) {
    use_cache = TRUE;
  }

  /* Lookup callbacks for this event. */
  for (evl = use_cache ? curr_evl : events; evl; evl = evl->next) {

    if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
      struct event_handler *evh;

      /* If there are no registered callbacks for this event, be done. */
      if (!evl->handlers) {
        pr_trace_msg(trace_channel, 8, "no event handlers registered for '%s'",
          event);
        return;
      }

      curr_event = event;
      curr_evl = evl;

      for (evh = use_cache ? curr_evh : evl->handlers; evh; evh = evh->next) {
        /* Make sure that if the same event is generated by the current
         * listener, the next time through we go to the next listener, rather
         * sending the same event against to the same listener (Bug#3619).
         */
        curr_evh = evh->next;

        if (!(evh->flags & PR_EVENT_FL_UNTRACED)) {
          if (evh->module) {
            pr_trace_msg(trace_channel, 8,
              "dispatching event '%s' to mod_%s (at %p, use cache = %s)", event,
              evh->module->name, evh->cb, use_cache ? "true" : "false");

          } else {
            pr_trace_msg(trace_channel, 8,
              "dispatching event '%s' to core (at %p, use cache = %s)", event,
              evh->cb, use_cache ? "true" : "false");
          }
        }

        evh->cb(event_data, evh->user_data);
      }

      break;
    }
  }

  /* Clear any cached data after publishing the event to all interested
   * listeners.
   */
  curr_event = NULL;
  curr_evl = NULL;
  curr_evh = NULL;
}

void pr_event_dump(void (*dumpf)(const char *, ...)) {
  struct event_list *evl;

  if (dumpf == NULL) {
    return;
  }

  if (events == NULL) {
    dumpf("%s", "No events registered");
    return;
  }

  for (evl = events; evl; evl = evl->next) {
    pr_signals_handle();

    if (evl->handlers == NULL) {
      dumpf("No handlers registered for '%s'", evl->event);

    } else {
      struct event_handler *evh;

      dumpf("Registered for '%s':", evl->event);
      for (evh = evl->handlers; evh; evh = evh->next) {
        if (evh->module != NULL) {
          dumpf("  mod_%s.c", evh->module->name);

        } else {
          dumpf("  (core)");
        }
      }
    }
  }
}

Coverage Report

Created: 2024-09-30 06:24

Line	Count	Source (jump to first uncovered line)
1		/*
2		* ProFTPD - FTP server daemon
3		* Copyright (c) 2003-2020 The ProFTPD Project team
4		*
5		* This program is free software; you can redistribute it and/or modify
6		* it under the terms of the GNU General Public License as published by
7		* the Free Software Foundation; either version 2 of the License, or
8		* (at your option) any later version.
9		*
10		* This program is distributed in the hope that it will be useful,
11		* but WITHOUT ANY WARRANTY; without even the implied warranty of
12		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13		* GNU General Public License for more details.
14		*
15		* You should have received a copy of the GNU General Public License
16		* along with this program; if not, write to the Free Software
17		* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
18		*
19		* As a special exemption, The ProFTPD Project team and other respective
20		* copyright holders give permission to link this program with OpenSSL, and
21		* distribute the resulting executable, without including the source code for
22		* OpenSSL in the source distribution.
23		*/
24
25		/* Event management code */
26
27		#include "conf.h"
28
29		/* Note: as more events are added, and as this API grows more and more used
30		* by the core code, look into using a different ADT for storage/retrieval
31		* of these objects, such as hash tables.
32		*/
33
34		struct event_handler {
35		struct event_handler next, prev;
36		module *module;
37		void (cb)(const void , void *);
38		void *user_data;
39		unsigned long flags;
40		};
41
42		struct event_list {
43		struct event_list *next;
44		pool *pool;
45		const char *event;
46		size_t event_len;
47		struct event_handler *handlers;
48		};
49
50		static pool *event_pool = NULL;
51		static struct event_list *events = NULL;
52
53		static const char *curr_event = NULL;
54		static struct event_list *curr_evl = NULL;
55		static struct event_handler *curr_evh = NULL;
56
57		/* Certain events are NOT logged via Trace logging (in order to prevent
58		* event/trace loops).
59		*/
60		static const char *untraced_events[] = {
61		PR_LOG_NAME_UNSPEC,
62		PR_LOG_NAME_XFERLOG,
63		PR_LOG_NAME_SYSLOG,
64		PR_LOG_NAME_SYSTEMLOG,
65		PR_LOG_NAME_EXTLOG,
66		PR_LOG_NAME_TRACELOG,
67		NULL
68		};
69
70	0	#define PR_EVENT_FL_UNTRACED 0x001
71
72		static const char *trace_channel = "event";
73
74	0	#define EVENT_POOL_SZ 256
75
76	0	static void event_cleanup_cb(void *user_data) {
77	0	event_pool = NULL;
78	0	events = NULL;
79
80	0	curr_event = NULL;
81	0	curr_evl = NULL;
82	0	curr_evh = NULL;
83	0	}
84
85		int pr_event_register(module m, const char event,
86	0	void (cb)(const void , void ), void user_data) {
87	0	register unsigned int i;
88	0	struct event_handler *evh;
89	0	struct event_list *evl;
90	0	pool *evl_pool;
91	0	unsigned long flags = 0;
92
93	0	if (event == NULL \|\|
94	0	cb == NULL) {
95	0	errno = EINVAL;
96	0	return -1;
97	0	}
98
99	0	if (event_pool == NULL) {
100	0	event_pool = make_sub_pool(permanent_pool);
101	0	pr_pool_tag(event_pool, "Event Pool");
102
103	0	register_cleanup2(event_pool, NULL, event_cleanup_cb);
104	0	}
105
106	0	pr_trace_msg(trace_channel, 3,
107	0	"module '%s' (%p) registering handler for event '%s' (at %p)",
108	0	m ? m->name : "(none)", m, event, cb);
109
110	0	evh = pcalloc(event_pool, sizeof(struct event_handler));
111
112	0	evh->module = m;
113	0	evh->cb = cb;
114	0	evh->user_data = user_data;
115
116		/* Is this an untraced event? */
117	0	for (i = 0; untraced_events[i] != NULL; i++) {
118	0	if (strcmp(event, untraced_events[i]) == 0) {
119	0	flags = PR_EVENT_FL_UNTRACED;
120	0	break;
121	0	}
122	0	}
123
124	0	evh->flags = flags;
125
126		/* Scan the currently registered lists, looking for where to add this
127		* registration.
128		*/
129
130	0	for (evl = events; evl; evl = evl->next) {
131	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
132	0	struct event_handler evhi, evhl = NULL;
133
134	0	evhi = evl->handlers;
135	0	if (evhi) {
136		/* Make sure this event handler is added to the START of the list,
137		* in order to preserve module load order handling of events (i.e.
138		* last module loaded, first module handled). The exception to this
139		* rule are core callbacks (i.e. where m == NULL); these will always
140		* be invoked last.
141		*
142		* Before that, though, check for duplicate registration/subscription.
143		*/
144	0	while (evhi) {
145	0	pr_signals_handle();
146
147	0	if (evhi->cb == evh->cb) {
148		/* Duplicate callback */
149	0	errno = EEXIST;
150	0	return -1;
151	0	}
152
153	0	evhl = evhi;
154
155	0	if (evhi->next == NULL) {
156	0	break;
157	0	}
158
159	0	evhi = evhi->next;
160	0	}
161
162	0	if (evh->module != NULL) {
163	0	if (evl->handlers != NULL) {
164	0	evl->handlers->prev = evh;
165	0	}
166
167	0	evh->next = evl->handlers;
168	0	evl->handlers = evh;
169
170	0	} else {
171		/* Core event listeners go at the end. */
172	0	evhl->next = evh;
173	0	evh->prev = evhl;
174	0	}
175
176	0	} else {
177	0	evl->handlers = evh;
178	0	}
179
180		/* All done */
181	0	return 0;
182	0	}
183	0	}
184
185	0	evl_pool = pr_pool_create_sz(event_pool, EVENT_POOL_SZ);
186	0	pr_pool_tag(evl_pool, "Event listener list pool");
187
188	0	evl = pcalloc(evl_pool, sizeof(struct event_list));
189	0	evl->pool = evl_pool;
190	0	evl->event = pstrdup(evl->pool, event);
191	0	evl->event_len = strlen(evl->event);
192	0	evl->handlers = evh;
193	0	evl->next = events;
194
195	0	events = evl;
196
197		/* Clear any cached data. */
198	0	curr_event = NULL;
199	0	curr_evl = NULL;
200	0	curr_evh = NULL;
201
202	0	return 0;
203	0	}
204
205		int pr_event_unregister(module m, const char event,
206	0	void (cb)(const void , void *)) {
207	0	struct event_list *evl;
208	0	int unregistered = FALSE;
209
210	0	if (events == NULL) {
211	0	return 0;
212	0	}
213
214	0	pr_trace_msg(trace_channel, 3,
215	0	"module '%s' (%p) unregistering handler for event '%s'",
216	0	m ? m->name : "(none)", m, event ? event : "(all)");
217
218		/* For now, simply remove the event_handler entry for this callback. In
219		* the future, add a static counter, and churn the event pool after a
220		* certain number of unregistrations, so that the memory pool doesn't
221		* grow unnecessarily.
222		*/
223
224	0	for (evl = events; evl; evl = evl->next) {
225	0	pr_signals_handle();
226
227	0	if (event == NULL \|\|
228	0	strncmp(evl->event, event, evl->event_len + 1) == 0) {
229	0	struct event_handler *evh;
230
231		/* If there are no handlers for this event, there is nothing to
232		* unregister. Skip on to the next list.
233		*/
234	0	if (evl->handlers == NULL) {
235	0	continue;
236	0	}
237
238	0	for (evh = evl->handlers; evh;) {
239
240	0	if ((m == NULL \|\| evh->module == m) &&
241	0	(cb == NULL \|\| evh->cb == cb)) {
242	0	struct event_handler *tmp = evh->next;
243
244	0	if (evh->next) {
245	0	evh->next->prev = evh->prev;
246	0	}
247
248	0	if (evh->prev) {
249	0	evh->prev->next = evh->next;
250
251	0	} else {
252		/* This is the head of the list. */
253	0	evl->handlers = evh->next;
254	0	}
255
256	0	evh->module = NULL;
257	0	evh = tmp;
258	0	unregistered = TRUE;
259
260	0	} else {
261	0	evh = evh->next;
262	0	}
263	0	}
264	0	}
265	0	}
266
267		/* Clear any cached data. */
268	0	curr_event = NULL;
269	0	curr_evl = NULL;
270	0	curr_evh = NULL;
271
272	0	if (!unregistered) {
273	0	errno = ENOENT;
274	0	return -1;
275	0	}
276
277	0	return 0;
278	0	}
279
280	1.42k	int pr_event_listening(const char *event) {
281	1.42k	struct event_list *evl;
282	1.42k	int count = 0;
283
284	1.42k	if (event == NULL) {
285	0	errno = EINVAL;
286	0	return -1;
287	0	}
288
289	1.42k	if (events == NULL) {
290		/* No registered listeners at all. */
291	1.42k	return 0;
292	1.42k	}
293
294		/* Lookup callbacks for this event. */
295	0	for (evl = events; evl; evl = evl->next) {
296
297	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
298	0	struct event_handler *evh;
299
300		/* If there are no registered callbacks for this event, be done. */
301	0	if (evl->handlers == NULL) {
302	0	return 0;
303	0	}
304
305	0	for (evh = evl->handlers; evh; evh = evh->next) {
306	0	count++;
307	0	}
308
309	0	break;
310	0	}
311	0	}
312
313	0	return count;
314	0	}
315
316	0	void pr_event_generate(const char event, const void event_data) {
317	0	int use_cache = FALSE;
318	0	struct event_list *evl;
319
320	0	if (event == NULL) {
321	0	return;
322	0	}
323
324		/* If there are no registered callbacks, be done. */
325	0	if (events == NULL) {
326	0	return;
327	0	}
328
329		/* If there is a cached event, see if the given event matches. */
330	0	if (curr_event != NULL &&
331	0	strcmp(curr_event, event) == 0) {
332	0	use_cache = TRUE;
333	0	}
334
335		/* Lookup callbacks for this event. */
336	0	for (evl = use_cache ? curr_evl : events; evl; evl = evl->next) {
337
338	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
339	0	struct event_handler *evh;
340
341		/* If there are no registered callbacks for this event, be done. */
342	0	if (!evl->handlers) {
343	0	pr_trace_msg(trace_channel, 8, "no event handlers registered for '%s'",
344	0	event);
345	0	return;
346	0	}
347
348	0	curr_event = event;
349	0	curr_evl = evl;
350
351	0	for (evh = use_cache ? curr_evh : evl->handlers; evh; evh = evh->next) {
352		/* Make sure that if the same event is generated by the current
353		* listener, the next time through we go to the next listener, rather
354		* sending the same event against to the same listener (Bug#3619).
355		*/
356	0	curr_evh = evh->next;
357
358	0	if (!(evh->flags & PR_EVENT_FL_UNTRACED)) {
359	0	if (evh->module) {
360	0	pr_trace_msg(trace_channel, 8,
361	0	"dispatching event '%s' to mod_%s (at %p, use cache = %s)", event,
362	0	evh->module->name, evh->cb, use_cache ? "true" : "false");
363
364	0	} else {
365	0	pr_trace_msg(trace_channel, 8,
366	0	"dispatching event '%s' to core (at %p, use cache = %s)", event,
367	0	evh->cb, use_cache ? "true" : "false");
368	0	}
369	0	}
370
371	0	evh->cb(event_data, evh->user_data);
372	0	}
373
374	0	break;
375	0	}
376	0	}
377
378		/* Clear any cached data after publishing the event to all interested
379		* listeners.
380		*/
381	0	curr_event = NULL;
382	0	curr_evl = NULL;
383	0	curr_evh = NULL;
384	0	}
385
386	0	void pr_event_dump(void (dumpf)(const char , ...)) {
387	0	struct event_list *evl;
388
389	0	if (dumpf == NULL) {
390	0	return;
391	0	}
392
393	0	if (events == NULL) {
394	0	dumpf("%s", "No events registered");
395	0	return;
396	0	}
397
398	0	for (evl = events; evl; evl = evl->next) {
399	0	pr_signals_handle();
400
401	0	if (evl->handlers == NULL) {
402	0	dumpf("No handlers registered for '%s'", evl->event);
403
404	0	} else {
405	0	struct event_handler *evh;
406
407	0	dumpf("Registered for '%s':", evl->event);
408	0	for (evh = evl->handlers; evh; evh = evh->next) {
409	0	if (evh->module != NULL) {
410	0	dumpf(" mod_%s.c", evh->module->name);
411
412	0	} else {
413	0	dumpf(" (core)");
414	0	}
415	0	}
416	0	}
417	0	}
418	0	}