[Asterisk-code-review] channel.c: Fix usage of CHECK BLOCKING() (asterisk[13])
Richard Mudgett
asteriskteam at digium.com
Tue Jun 19 15:04:04 CDT 2018
Richard Mudgett has uploaded this change for review. ( https://gerrit.asterisk.org/9212
Change subject: channel.c: Fix usage of CHECK_BLOCKING()
......................................................................
channel.c: Fix usage of CHECK_BLOCKING()
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
---
M include/asterisk/channel.h
M main/channel.c
2 files changed, 44 insertions(+), 17 deletions(-)
git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/12/9212/1
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index 0fc236a..8c171b6 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -2649,15 +2649,30 @@
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);
diff --git a/main/channel.c b/main/channel.c
index 27a959a..2a72aee 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3266,10 +3266,10 @@
}
}
- 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 @@
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 @@
/* 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 @@
whentohangup = diff;
}
}
- ast_channel_unlock(c[i]);
CHECK_BLOCKING(c[i]);
+ ast_channel_unlock(c[i]);
}
rms = *ms;
@@ -3365,7 +3369,9 @@
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 @@
}
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 @@
/* 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 @@
/* 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 @@
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 @@
}
}
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 @@
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 @@
/* 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 @@
} 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 @@
/* 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) {
--
To view, visit https://gerrit.asterisk.org/9212
To unsubscribe, visit https://gerrit.asterisk.org/settings
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-MessageType: newchange
Gerrit-Change-Id: I4dfc33e01e60627d962efa29d0a4244cf151a84d
Gerrit-Change-Number: 9212
Gerrit-PatchSet: 1
Gerrit-Owner: Richard Mudgett <rmudgett at digium.com>
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