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channel.c: Fix usage of CHECK_BLOCKING()

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The CHECK_BLOCKING() macro is used to indicate if a channel's handling
thread is about to do a blocking operation (poll, read, or write) of
media.  A few operations such as ast_queue_frame(), soft hangup, and
masquerades use the indication to wake up the blocked thread to reevaluate
what is going on.

ASTERISK-27625

Change-Id: I4dfc33e01e60627d962efa29d0a4244cf151a84d
This commit is contained in:
Richard Mudgett
2018-06-12 14:09:54 -05:00
parent 5d34ca5b33
commit 1abcc41fff
2 changed files with 44 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
include/asterisk/channel.h
View File

@@ -2649,15 +2649,30 @@ static inline enum ast_t38_state ast_channel_get_t38_state(struct ast_channel *c
return state;
}
#define CHECK_BLOCKING(c) do { \
if (ast_test_flag(ast_channel_flags(c), AST_FLAG_BLOCKING)) {\
ast_debug(1, "Thread %p is blocking '%s', already blocked by thread %p in procedure %s\n", \
(void *) pthread_self(), ast_channel_name(c), (void *) ast_channel_blocker(c), ast_channel_blockproc(c)); \
} else { \
/*!
* \brief Set the blocking indication on the channel.
*
* \details
* Indicate that the thread handling the channel is about to do a blocking
* operation to wait for media on the channel. (poll, read, or write)
*
* Masquerading and ast_queue_frame() use this indication to wake up the thread.
*
* \pre The channel needs to be locked
*/
#define CHECK_BLOCKING(c) \
do { \
if (ast_test_flag(ast_channel_flags(c), AST_FLAG_BLOCKING)) { \
/* This should not happen as there should only be one thread handling a channel's media at a time. */ \
ast_log(LOG_DEBUG, "Thread %p is blocking '%s', already blocked by thread %p in procedure %s\n", \
(void *) pthread_self(), ast_channel_name(c), \
(void *) ast_channel_blocker(c), ast_channel_blockproc(c)); \
ast_assert(0); \
} \
ast_channel_blocker_set((c), pthread_self()); \
ast_channel_blockproc_set((c), __PRETTY_FUNCTION__); \
ast_set_flag(ast_channel_flags(c), AST_FLAG_BLOCKING); \
} } while (0)
} while (0)
ast_group_t ast_get_group(const char *s);

34
main/channel.c
View File

@@ -3266,11 +3266,11 @@ static struct ast_channel *ast_waitfor_nandfds_simple(struct ast_channel *chan,
}
}
ast_channel_unlock(chan);
/* Time to make this channel block... */
CHECK_BLOCKING(chan);
ast_channel_unlock(chan);
if (*ms > 0) {
start = ast_tvnow();
}
@@ -3279,7 +3279,9 @@ static struct ast_channel *ast_waitfor_nandfds_simple(struct ast_channel *chan,
res = epoll_wait(ast_channel_epfd(chan), ev, 1, rms);
/* Stop blocking */
ast_channel_lock(chan);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
ast_channel_unlock(chan);
/* Simulate a timeout if we were interrupted */
if (res < 0) {
@@ -3305,12 +3307,14 @@ static struct ast_channel *ast_waitfor_nandfds_simple(struct ast_channel *chan,
/* See what events are pending */
aed = ev[0].data.ptr;
ast_channel_lock(chan);
ast_channel_fdno_set(chan, aed->which);
if (ev[0].events & EPOLLPRI) {
ast_set_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
} else {
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
}
ast_channel_unlock(chan);
if (*ms > 0) {
*ms -= ast_tvdiff_ms(ast_tvnow(), start);
@@ -3346,8 +3350,8 @@ static struct ast_channel *ast_waitfor_nandfds_complex(struct ast_channel **c, i
whentohangup = diff;
}
}
ast_channel_unlock(c[i]);
CHECK_BLOCKING(c[i]);
ast_channel_unlock(c[i]);
}
rms = *ms;
@@ -3365,7 +3369,9 @@ static struct ast_channel *ast_waitfor_nandfds_complex(struct ast_channel **c, i
res = epoll_wait(ast_channel_epfd(c[0]), ev, 25, rms);
for (i = 0; i < n; i++) {
ast_channel_lock(c[i]);
ast_clear_flag(ast_channel_flags(c[i]), AST_FLAG_BLOCKING);
ast_channel_unlock(c[i]);
}
if (res < 0) {
@@ -3400,12 +3406,14 @@ static struct ast_channel *ast_waitfor_nandfds_complex(struct ast_channel **c, i
}
winner = aed->chan;
ast_channel_lock(winner);
if (ev[i].events & EPOLLPRI) {
ast_set_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
} else {
ast_clear_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
}
ast_channel_fdno_set(winner, aed->which);
ast_channel_unlock(winner);
}
if (*ms > 0) {
@@ -5220,11 +5228,9 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
/* There is a generator running while we're in the middle of a digit.
* It's probably inband DTMF, so go ahead and pass it so it can
* stop the generator */
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
ast_channel_unlock(chan);
res = ast_senddigit_end(chan, fr->subclass.integer, fr->len);
ast_channel_lock(chan);
CHECK_BLOCKING(chan);
} else if (fr->frametype == AST_FRAME_CONTROL
&& fr->subclass.integer == AST_CONTROL_UNHOLD) {
/*
@@ -5242,7 +5248,6 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
/* High bit prints debugging */
if (ast_channel_fout(chan) & DEBUGCHAN_FLAG)
ast_frame_dump(ast_channel_name(chan), fr, ">>");
CHECK_BLOCKING(chan);
switch (fr->frametype) {
case AST_FRAME_CONTROL:
indicate_data_internal(chan, fr->subclass.integer, fr->data.ptr, fr->datalen);
@@ -5256,11 +5261,9 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
f = fr;
}
send_dtmf_begin_event(chan, DTMF_SENT, fr->subclass.integer);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
ast_channel_unlock(chan);
res = ast_senddigit_begin(chan, fr->subclass.integer);
ast_channel_lock(chan);
CHECK_BLOCKING(chan);
break;
case AST_FRAME_DTMF_END:
if (ast_channel_audiohooks(chan)) {
@@ -5272,13 +5275,12 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
}
}
send_dtmf_end_event(chan, DTMF_SENT, fr->subclass.integer, fr->len);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
ast_channel_unlock(chan);
res = ast_senddigit_end(chan, fr->subclass.integer, fr->len);
ast_channel_lock(chan);
CHECK_BLOCKING(chan);
break;
case AST_FRAME_TEXT:
CHECK_BLOCKING(chan);
if (ast_format_cmp(fr->subclass.format, ast_format_t140) == AST_FORMAT_CMP_EQUAL) {
res = (ast_channel_tech(chan)->write_text == NULL) ? 0 :
ast_channel_tech(chan)->write_text(chan, fr);
@@ -5286,19 +5288,26 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
res = (ast_channel_tech(chan)->send_text == NULL) ? 0 :
ast_channel_tech(chan)->send_text(chan, (char *) fr->data.ptr);
}
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
case AST_FRAME_HTML:
CHECK_BLOCKING(chan);
res = (ast_channel_tech(chan)->send_html == NULL) ? 0 :
ast_channel_tech(chan)->send_html(chan, fr->subclass.integer, (char *) fr->data.ptr, fr->datalen);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
case AST_FRAME_VIDEO:
/* XXX Handle translation of video codecs one day XXX */
CHECK_BLOCKING(chan);
res = (ast_channel_tech(chan)->write_video == NULL) ? 0 :
ast_channel_tech(chan)->write_video(chan, fr);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
case AST_FRAME_MODEM:
CHECK_BLOCKING(chan);
res = (ast_channel_tech(chan)->write == NULL) ? 0 :
ast_channel_tech(chan)->write(chan, fr);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
case AST_FRAME_VOICE:
if (ast_channel_tech(chan)->write == NULL)
@@ -5459,6 +5468,7 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
/* the translator on chan->writetrans may have returned multiple frames
from the single frame we passed in; if so, feed each one of them to the
channel, freeing each one after it has been written */
CHECK_BLOCKING(chan);
if ((f != fr) && AST_LIST_NEXT(f, frame_list)) {
struct ast_frame *cur, *next = NULL;
unsigned int skip = 0;
@@ -5487,6 +5497,7 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
} else {
res = ast_channel_tech(chan)->write(chan, f);
}
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
case AST_FRAME_NULL:
case AST_FRAME_IAX:
@@ -5497,13 +5508,14 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
/* At this point, fr is the incoming frame and f is NULL. Channels do
* not expect to get NULL as a frame pointer and will segfault. Hence,
* we output the original frame passed in. */
CHECK_BLOCKING(chan);
res = ast_channel_tech(chan)->write(chan, fr);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
break;
}
if (f && f != fr)
ast_frfree(f);
ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);
/* Consider a write failure to force a soft hangup */
if (res < 0) {