/src/proftpd/src/event.c

Source
/*
 * ProFTPD - FTP server daemon
 * Copyright (c) 2003-2026 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, see <https://www.gnu.org/licenses/>.
 *
 * 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: 2026-09-03 06:37

Line	Count	Source
1		/*
2		* ProFTPD - FTP server daemon
3		* Copyright (c) 2003-2026 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, see <https://www.gnu.org/licenses/>.
17		*
18		* As a special exemption, The ProFTPD Project team and other respective
19		* copyright holders give permission to link this program with OpenSSL, and
20		* distribute the resulting executable, without including the source code for
21		* OpenSSL in the source distribution.
22		*/
23
24		/* Event management code */
25
26		#include "conf.h"
27
28		/* Note: as more events are added, and as this API grows more and more used
29		* by the core code, look into using a different ADT for storage/retrieval
30		* of these objects, such as hash tables.
31		*/
32
33		struct event_handler {
34		struct event_handler next, prev;
35		module *module;
36		void (cb)(const void , void *);
37		void *user_data;
38		unsigned long flags;
39		};
40
41		struct event_list {
42		struct event_list *next;
43		pool *pool;
44		const char *event;
45		size_t event_len;
46		struct event_handler *handlers;
47		};
48
49		static pool *event_pool = NULL;
50		static struct event_list *events = NULL;
51
52		static const char *curr_event = NULL;
53		static struct event_list *curr_evl = NULL;
54		static struct event_handler *curr_evh = NULL;
55
56		/* Certain events are NOT logged via Trace logging (in order to prevent
57		* event/trace loops).
58		*/
59		static const char *untraced_events[] = {
60		PR_LOG_NAME_UNSPEC,
61		PR_LOG_NAME_XFERLOG,
62		PR_LOG_NAME_SYSLOG,
63		PR_LOG_NAME_SYSTEMLOG,
64		PR_LOG_NAME_EXTLOG,
65		PR_LOG_NAME_TRACELOG,
66		NULL
67		};
68
69	0	#define PR_EVENT_FL_UNTRACED 0x001
70
71		static const char *trace_channel = "event";
72
73	0	#define EVENT_POOL_SZ 256
74
75	0	static void event_cleanup_cb(void *user_data) {
76	0	event_pool = NULL;
77	0	events = NULL;
78
79	0	curr_event = NULL;
80	0	curr_evl = NULL;
81	0	curr_evh = NULL;
82	0	}
83
84		int pr_event_register(module m, const char event,
85	0	void (cb)(const void , void ), void user_data) {
86	0	register unsigned int i;
87	0	struct event_handler *evh;
88	0	struct event_list *evl;
89	0	pool *evl_pool;
90	0	unsigned long flags = 0;
91
92	0	if (event == NULL \|\|
93	0	cb == NULL) {
94	0	errno = EINVAL;
95	0	return -1;
96	0	}
97
98	0	if (event_pool == NULL) {
99	0	event_pool = make_sub_pool(permanent_pool);
100	0	pr_pool_tag(event_pool, "Event Pool");
101
102	0	register_cleanup2(event_pool, NULL, event_cleanup_cb);
103	0	}
104
105	0	pr_trace_msg(trace_channel, 3,
106	0	"module '%s' (%p) registering handler for event '%s' (at %p)",
107	0	m ? m->name : "(none)", m, event, cb);
108
109	0	evh = pcalloc(event_pool, sizeof(struct event_handler));
110
111	0	evh->module = m;
112	0	evh->cb = cb;
113	0	evh->user_data = user_data;
114
115		/* Is this an untraced event? */
116	0	for (i = 0; untraced_events[i] != NULL; i++) {
117	0	if (strcmp(event, untraced_events[i]) == 0) {
118	0	flags = PR_EVENT_FL_UNTRACED;
119	0	break;
120	0	}
121	0	}
122
123	0	evh->flags = flags;
124
125		/* Scan the currently registered lists, looking for where to add this
126		* registration.
127		*/
128
129	0	for (evl = events; evl; evl = evl->next) {
130	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
131	0	struct event_handler evhi, evhl = NULL;
132
133	0	evhi = evl->handlers;
134	0	if (evhi) {
135		/* Make sure this event handler is added to the START of the list,
136		* in order to preserve module load order handling of events (i.e.
137		* last module loaded, first module handled). The exception to this
138		* rule are core callbacks (i.e. where m == NULL); these will always
139		* be invoked last.
140		*
141		* Before that, though, check for duplicate registration/subscription.
142		*/
143	0	while (evhi) {
144	0	pr_signals_handle();
145
146	0	if (evhi->cb == evh->cb) {
147		/* Duplicate callback */
148	0	errno = EEXIST;
149	0	return -1;
150	0	}
151
152	0	evhl = evhi;
153
154	0	if (evhi->next == NULL) {
155	0	break;
156	0	}
157
158	0	evhi = evhi->next;
159	0	}
160
161	0	if (evh->module != NULL) {
162	0	if (evl->handlers != NULL) {
163	0	evl->handlers->prev = evh;
164	0	}
165
166	0	evh->next = evl->handlers;
167	0	evl->handlers = evh;
168
169	0	} else {
170		/* Core event listeners go at the end. */
171	0	evhl->next = evh;
172	0	evh->prev = evhl;
173	0	}
174
175	0	} else {
176	0	evl->handlers = evh;
177	0	}
178
179		/* All done */
180	0	return 0;
181	0	}
182	0	}
183
184	0	evl_pool = pr_pool_create_sz(event_pool, EVENT_POOL_SZ);
185	0	pr_pool_tag(evl_pool, "Event listener list pool");
186
187	0	evl = pcalloc(evl_pool, sizeof(struct event_list));
188	0	evl->pool = evl_pool;
189	0	evl->event = pstrdup(evl->pool, event);
190	0	evl->event_len = strlen(evl->event);
191	0	evl->handlers = evh;
192	0	evl->next = events;
193
194	0	events = evl;
195
196		/* Clear any cached data. */
197	0	curr_event = NULL;
198	0	curr_evl = NULL;
199	0	curr_evh = NULL;
200
201	0	return 0;
202	0	}
203
204		int pr_event_unregister(module m, const char event,
205	0	void (cb)(const void , void *)) {
206	0	struct event_list *evl;
207	0	int unregistered = FALSE;
208
209	0	if (events == NULL) {
210	0	return 0;
211	0	}
212
213	0	pr_trace_msg(trace_channel, 3,
214	0	"module '%s' (%p) unregistering handler for event '%s'",
215	0	m ? m->name : "(none)", m, event ? event : "(all)");
216
217		/* For now, simply remove the event_handler entry for this callback. In
218		* the future, add a static counter, and churn the event pool after a
219		* certain number of unregistrations, so that the memory pool doesn't
220		* grow unnecessarily.
221		*/
222
223	0	for (evl = events; evl; evl = evl->next) {
224	0	pr_signals_handle();
225
226	0	if (event == NULL \|\|
227	0	strncmp(evl->event, event, evl->event_len + 1) == 0) {
228	0	struct event_handler *evh;
229
230		/* If there are no handlers for this event, there is nothing to
231		* unregister. Skip on to the next list.
232		*/
233	0	if (evl->handlers == NULL) {
234	0	continue;
235	0	}
236
237	0	for (evh = evl->handlers; evh;) {
238
239	0	if ((m == NULL \|\| evh->module == m) &&
240	0	(cb == NULL \|\| evh->cb == cb)) {
241	0	struct event_handler *tmp = evh->next;
242
243	0	if (evh->next) {
244	0	evh->next->prev = evh->prev;
245	0	}
246
247	0	if (evh->prev) {
248	0	evh->prev->next = evh->next;
249
250	0	} else {
251		/* This is the head of the list. */
252	0	evl->handlers = evh->next;
253	0	}
254
255	0	evh->module = NULL;
256	0	evh = tmp;
257	0	unregistered = TRUE;
258
259	0	} else {
260	0	evh = evh->next;
261	0	}
262	0	}
263	0	}
264	0	}
265
266		/* Clear any cached data. */
267	0	curr_event = NULL;
268	0	curr_evl = NULL;
269	0	curr_evh = NULL;
270
271	0	if (!unregistered) {
272	0	errno = ENOENT;
273	0	return -1;
274	0	}
275
276	0	return 0;
277	0	}
278
279	5.23k	int pr_event_listening(const char *event) {
280	5.23k	struct event_list *evl;
281	5.23k	int count = 0;
282
283	5.23k	if (event == NULL) {
284	0	errno = EINVAL;
285	0	return -1;
286	0	}
287
288	5.23k	if (events == NULL) {
289		/* No registered listeners at all. */
290	5.23k	return 0;
291	5.23k	}
292
293		/* Lookup callbacks for this event. */
294	0	for (evl = events; evl; evl = evl->next) {
295
296	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
297	0	struct event_handler *evh;
298
299		/* If there are no registered callbacks for this event, be done. */
300	0	if (evl->handlers == NULL) {
301	0	return 0;
302	0	}
303
304	0	for (evh = evl->handlers; evh; evh = evh->next) {
305	0	count++;
306	0	}
307
308	0	break;
309	0	}
310	0	}
311
312	0	return count;
313	0	}
314
315	0	void pr_event_generate(const char event, const void event_data) {
316	0	int use_cache = FALSE;
317	0	struct event_list *evl;
318
319	0	if (event == NULL) {
320	0	return;
321	0	}
322
323		/* If there are no registered callbacks, be done. */
324	0	if (events == NULL) {
325	0	return;
326	0	}
327
328		/* If there is a cached event, see if the given event matches. */
329	0	if (curr_event != NULL &&
330	0	strcmp(curr_event, event) == 0) {
331	0	use_cache = TRUE;
332	0	}
333
334		/* Lookup callbacks for this event. */
335	0	for (evl = use_cache ? curr_evl : events; evl; evl = evl->next) {
336
337	0	if (strncmp(evl->event, event, evl->event_len + 1) == 0) {
338	0	struct event_handler *evh;
339
340		/* If there are no registered callbacks for this event, be done. */
341	0	if (!evl->handlers) {
342	0	pr_trace_msg(trace_channel, 8, "no event handlers registered for '%s'",
343	0	event);
344	0	return;
345	0	}
346
347	0	curr_event = event;
348	0	curr_evl = evl;
349
350	0	for (evh = use_cache ? curr_evh : evl->handlers; evh; evh = evh->next) {
351		/* Make sure that if the same event is generated by the current
352		* listener, the next time through we go to the next listener, rather
353		* sending the same event against to the same listener (Bug#3619).
354		*/
355	0	curr_evh = evh->next;
356
357	0	if (!(evh->flags & PR_EVENT_FL_UNTRACED)) {
358	0	if (evh->module) {
359	0	pr_trace_msg(trace_channel, 8,
360	0	"dispatching event '%s' to mod_%s (at %p, use cache = %s)", event,
361	0	evh->module->name, evh->cb, use_cache ? "true" : "false");
362
363	0	} else {
364	0	pr_trace_msg(trace_channel, 8,
365	0	"dispatching event '%s' to core (at %p, use cache = %s)", event,
366	0	evh->cb, use_cache ? "true" : "false");
367	0	}
368	0	}
369
370	0	evh->cb(event_data, evh->user_data);
371	0	}
372
373	0	break;
374	0	}
375	0	}
376
377		/* Clear any cached data after publishing the event to all interested
378		* listeners.
379		*/
380	0	curr_event = NULL;
381	0	curr_evl = NULL;
382	0	curr_evh = NULL;
383	0	}
384
385	0	void pr_event_dump(void (dumpf)(const char , ...)) {
386	0	struct event_list *evl;
387
388	0	if (dumpf == NULL) {
389	0	return;
390	0	}
391
392	0	if (events == NULL) {
393	0	dumpf("%s", "No events registered");
394	0	return;
395	0	}
396
397	0	for (evl = events; evl; evl = evl->next) {
398	0	pr_signals_handle();
399
400	0	if (evl->handlers == NULL) {
401	0	dumpf("No handlers registered for '%s'", evl->event);
402
403	0	} else {
404	0	struct event_handler *evh;
405
406	0	dumpf("Registered for '%s':", evl->event);
407	0	for (evh = evl->handlers; evh; evh = evh->next) {
408	0	if (evh->module != NULL) {
409	0	dumpf(" mod_%s.c", evh->module->name);
410
411	0	} else {
412	0	dumpf(" (core)");
413	0	}
414	0	}
415	0	}
416	0	}
417	0	}