channel: Remove old epoll support and fixed max number of file descriptors.

This change removes the old epoll support which has not been used or
maintained in quite some time.

The fixed number of file descriptors on a channel has also been removed.
File descriptors are now contained in a growable vector. This can be
used like before by specifying a specific position to store a file
descriptor at or using a new API call, ast_channel_fd_add, which adds
a file descriptor to the channel and returns its position.

Tests have been added which cover the growing behavior of the vector
and the new API call.

ASTERISK-26885

Change-Id: I1a754b506c009b83dfdeeb08c2d2815db30ef928

main/channel_internal_api.c

@@ -48,6 +48,7 @@
 #include "asterisk/stringfields.h"
 #include "asterisk/stream.h"
 #include "asterisk/test.h"
+#include "asterisk/vector.h"
 
 /*!
  * \brief Channel UniqueId structure
@@ -96,9 +97,6 @@ struct ast_channel {
 							 *   in the CHANNEL dialplan function */
 	struct ast_channel_monitor *monitor;		/*!< Channel monitoring */
 	ast_callid callid;			/*!< Bound call identifier pointer */
-#ifdef HAVE_EPOLL
-	struct ast_epoll_data *epfd_data[AST_MAX_FDS];
-#endif
 	struct ao2_container *dialed_causes;		/*!< Contains tech-specific and Asterisk cause data from dialed channels */
 
 	AST_DECLARE_STRING_FIELDS(
@@ -167,7 +165,7 @@ struct ast_channel {
 	unsigned long insmpl;				/*!< Track the read/written samples for monitor use */
 	unsigned long outsmpl;				/*!< Track the read/written samples for monitor use */
 
-	int fds[AST_MAX_FDS];				/*!< File descriptors for channel -- Drivers will poll on
+	AST_VECTOR(, int) fds;				/*!< File descriptors for channel -- Drivers will poll on
 							 *   these file descriptors, so at least one must be non -1.
 							 *   See \arg \ref AstFileDesc */
 	int softhangup;				/*!< Whether or not we have been hung up...  Do not set this value
@@ -197,9 +195,6 @@ struct ast_channel {
 	struct ast_format *rawreadformat;         /*!< Raw read format (before translation) */
 	struct ast_format *rawwriteformat;        /*!< Raw write format (after translation) */
 	unsigned int emulate_dtmf_duration;		/*!< Number of ms left to emulate DTMF for */
-#ifdef HAVE_EPOLL
-	int epfd;
-#endif
 	int visible_indication;                         /*!< Indication currently playing on the channel */
 	int hold_state;							/*!< Current Hold/Unhold state */
 
@@ -597,17 +592,6 @@ void ast_channel_amaflags_set(struct ast_channel *chan, enum ama_flags value)
 	chan->amaflags = value;
 	ast_channel_publish_snapshot(chan);
 }
-
-#ifdef HAVE_EPOLL
-int ast_channel_epfd(const struct ast_channel *chan)
-{
-	return chan->epfd;
-}
-void ast_channel_epfd_set(struct ast_channel *chan, int value)
-{
-	chan->epfd = value;
-}
-#endif
 int ast_channel_fdno(const struct ast_channel *chan)
 {
 	return chan->fdno;
@@ -1432,38 +1416,55 @@ void ast_channel_internal_alertpipe_swap(struct ast_channel *chan1, struct ast_c
 /* file descriptor array accessors */
 void ast_channel_internal_fd_set(struct ast_channel *chan, int which, int value)
 {
-	chan->fds[which] = value;
+	int pos;
+
+	/* This ensures that if the vector has to grow with unused positions they will be
+	 * initialized to -1.
+	 */
+	for (pos = AST_VECTOR_SIZE(&chan->fds); pos < which; pos++) {
+		AST_VECTOR_REPLACE(&chan->fds, pos, -1);
+	}
+
+	AST_VECTOR_REPLACE(&chan->fds, which, value);
 }
 void ast_channel_internal_fd_clear(struct ast_channel *chan, int which)
 {
-	ast_channel_internal_fd_set(chan, which, -1);
+	if (which >= AST_VECTOR_SIZE(&chan->fds)) {
+		return;
+	}
+
+	AST_VECTOR_REPLACE(&chan->fds, which, -1);
 }
 void ast_channel_internal_fd_clear_all(struct ast_channel *chan)
 {
-	int i;
-	for (i = 0; i < AST_MAX_FDS; i++) {
-		ast_channel_internal_fd_clear(chan, i);
-	}
+	AST_VECTOR_RESET(&chan->fds, AST_VECTOR_ELEM_CLEANUP_NOOP);
 }
 int ast_channel_fd(const struct ast_channel *chan, int which)
 {
-	return chan->fds[which];
+	return (which >= AST_VECTOR_SIZE(&chan->fds)) ? -1 : AST_VECTOR_GET(&chan->fds, which);
 }
 int ast_channel_fd_isset(const struct ast_channel *chan, int which)
 {
 	return ast_channel_fd(chan, which) > -1;
 }
 
-#ifdef HAVE_EPOLL
-struct ast_epoll_data *ast_channel_internal_epfd_data(const struct ast_channel *chan, int which)
+int ast_channel_fd_count(const struct ast_channel *chan)
 {
-	return chan->epfd_data[which];
+	return AST_VECTOR_SIZE(&chan->fds);
 }
-void ast_channel_internal_epfd_data_set(struct ast_channel *chan, int which , struct ast_epoll_data *value)
+
+int ast_channel_fd_add(struct ast_channel *chan, int value)
 {
-	chan->epfd_data[which] = value;
+	int pos = AST_EXTENDED_FDS;
+
+	while (ast_channel_fd_isset(chan, pos)) {
+		pos += 1;
+	}
+
+	AST_VECTOR_REPLACE(&chan->fds, pos, value);
+
+	return pos;
 }
-#endif
 
 pthread_t ast_channel_blocker(const struct ast_channel *chan)
 {
@@ -1617,6 +1618,8 @@ struct ast_channel *__ast_channel_internal_alloc(void (*destructor)(void *obj),
 		tmp->linkedid = tmp->uniqueid;
 	}
 
+	AST_VECTOR_INIT(&tmp->fds, AST_MAX_FDS);
+
 	return tmp;
 }
 
@@ -1693,6 +1696,8 @@ void ast_channel_internal_cleanup(struct ast_channel *chan)
 	chan->topics = NULL;
 
 	ast_channel_internal_set_stream_topology(chan, NULL);
+
+	AST_VECTOR_FREE(&chan->fds);
 }
 
 void ast_channel_internal_finalize(struct ast_channel *chan)