diff --git a/apps/app_chanspy.c b/apps/app_chanspy.c
index 77a4ffe85d134138a8047ae34c96756faede667c..21e466fb3b930f0cb2c069150d67a7cac8881f2a 100644
--- a/apps/app_chanspy.c
+++ b/apps/app_chanspy.c
@@ -222,23 +222,31 @@ static struct ast_generator spygen = {
.generate = spy_generate,
};
-static int start_spying(struct ast_channel *chan, struct ast_channel *spychan, struct ast_audiohook *audiohook)
+static int start_spying(struct ast_channel *chan, const char *spychan_name, struct ast_audiohook *audiohook)
{
int res = 0;
struct ast_channel *peer = NULL;
- ast_log(LOG_NOTICE, "Attaching %s to %s\n", spychan->name, chan->name);
+ ast_log(LOG_NOTICE, "Attaching %s to %s\n", spychan_name, chan->name);
res = ast_audiohook_attach(chan, audiohook);
- if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan)))
+ if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) {
+ ast_channel_unlock(chan);
ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);
+ } else
+ ast_channel_unlock(chan);
return res;
}
-static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int *volfactor, int fd,
- const struct ast_flags *flags, char *exitcontext)
+struct chanspy_ds {
+ struct ast_channel *chan;
+ ast_mutex_t lock;
+};
+
+static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chanspy_ds,
+ int *volfactor, int fd, const struct ast_flags *flags, char *exitcontext)
{
struct chanspy_translation_helper csth;
int running = 0, res, x = 0;
@@ -246,6 +254,24 @@ static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int
char *name;
struct ast_frame *f;
struct ast_silence_generator *silgen = NULL;
+ struct ast_channel *spyee = NULL;
+ const char *spyer_name;
+
+ ast_channel_lock(chan);
+ spyer_name = ast_strdupa(chan->name);
+ ast_channel_unlock(chan);
+
+ ast_mutex_lock(&spyee_chanspy_ds->lock);
+ if (spyee_chanspy_ds->chan) {
+ spyee = spyee_chanspy_ds->chan;
+ ast_channel_lock(spyee);
+ }
+ ast_mutex_unlock(&spyee_chanspy_ds->lock);
+
+ if (!spyee)
+ return 0;
+
+ /* We now hold the channel lock on spyee */
if (ast_check_hangup(chan) || ast_check_hangup(spyee))
return 0;
@@ -257,16 +283,18 @@ static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int
ast_audiohook_init(&csth.spy_audiohook, AST_AUDIOHOOK_TYPE_SPY, "ChanSpy");
- if (start_spying(spyee, chan, &csth.spy_audiohook)) {
+ if (start_spying(spyee, spyer_name, &csth.spy_audiohook)) { /* Unlocks spyee */
ast_audiohook_destroy(&csth.spy_audiohook);
return 0;
}
if (ast_test_flag(flags, OPTION_WHISPER)) {
ast_audiohook_init(&csth.whisper_audiohook, AST_AUDIOHOOK_TYPE_WHISPER, "ChanSpy");
- start_spying(spyee, chan, &csth.whisper_audiohook);
+ start_spying(spyee, spyer_name, &csth.whisper_audiohook); /* Unlocks spyee */
}
+ spyee = NULL;
+
csth.volfactor = *volfactor;
if (csth.volfactor) {
@@ -380,12 +408,82 @@ static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int
return running;
}
-static struct ast_channel *next_channel(const struct ast_channel *last, const char *spec,
- const char *exten, const char *context)
+/*!
+ * \note This relies on the embedded lock to be recursive, as it may be called
+ * due to a call to chanspy_ds_free with the lock held there.
+ */
+static void chanspy_ds_destroy(void *data)
+{
+ struct chanspy_ds *chanspy_ds = data;
+
+ /* Setting chan to be NULL is an atomic operation, but we don't want this
+ * value to change while this lock is held. The lock is held elsewhere
+ * while it performs non-atomic operations with this channel pointer */
+
+ ast_mutex_lock(&chanspy_ds->lock);
+ chanspy_ds->chan = NULL;
+ ast_mutex_unlock(&chanspy_ds->lock);
+}
+
+static const struct ast_datastore_info chanspy_ds_info = {
+ .type = "chanspy",
+ .destroy = chanspy_ds_destroy,
+};
+
+static struct chanspy_ds *chanspy_ds_free(struct chanspy_ds *chanspy_ds)
+{
+ if (!chanspy_ds)
+ return NULL;
+
+ ast_mutex_lock(&chanspy_ds->lock);
+ if (chanspy_ds->chan) {
+ struct ast_datastore *datastore;
+ struct ast_channel *chan;
+
+ chan = chanspy_ds->chan;
+
+ ast_channel_lock(chan);
+ if ((datastore = ast_channel_datastore_find(chan, &chanspy_ds_info, NULL))) {
+ ast_channel_datastore_remove(chan, datastore);
+ /* chanspy_ds->chan is NULL after this call */
+ ast_channel_datastore_free(datastore);
+ }
+ ast_channel_unlock(chan);
+ }
+ ast_mutex_unlock(&chanspy_ds->lock);
+
+ return NULL;
+}
+
+/*! \note Returns the channel in the chanspy_ds locked as well as the chanspy_ds locked */
+static struct chanspy_ds *setup_chanspy_ds(struct ast_channel *chan, struct chanspy_ds *chanspy_ds)
+{
+ struct ast_datastore *datastore = NULL;
+
+ ast_mutex_lock(&chanspy_ds->lock);
+
+ chanspy_ds->chan = chan;
+
+ if (!(datastore = ast_channel_datastore_alloc(&chanspy_ds_info, NULL))) {
+ chanspy_ds = chanspy_ds_free(chanspy_ds);
+ ast_channel_unlock(chan);
+ return NULL;
+ }
+
+ datastore->data = chanspy_ds;
+
+ ast_channel_datastore_add(chan, datastore);
+
+ return chanspy_ds;
+}
+
+static struct chanspy_ds *next_channel(struct ast_channel *chan,
+ const struct ast_channel *last, const char *spec,
+ const char *exten, const char *context, struct chanspy_ds *chanspy_ds)
{
struct ast_channel *this;
- redo:
+redo:
if (!ast_strlen_zero(spec))
this = ast_walk_channel_by_name_prefix_locked(last, spec, strlen(spec));
@@ -394,20 +492,21 @@ static struct ast_channel *next_channel(const struct ast_channel *last, const ch
else
this = ast_channel_walk_locked(last);
- if (this) {
+ if (!this)
+ return NULL;
+
+ if (!strncmp(this->name, "Zap/pseudo", 10)) {
ast_channel_unlock(this);
- if (!strncmp(this->name, "Zap/pseudo", 10))
- goto redo;
+ goto redo;
}
- return this;
+ return setup_chanspy_ds(this, chanspy_ds);
}
static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
int volfactor, const int fd, const char *mygroup, const char *myenforced,
const char *spec, const char *exten, const char *context)
{
- struct ast_channel *peer, *prev, *next;
char nameprefix[AST_NAME_STRLEN];
char peer_name[AST_NAME_STRLEN + 5];
char exitcontext[AST_MAX_CONTEXT] = "";
@@ -417,6 +516,7 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
char *ptr;
int num;
int num_spyed_upon = 1;
+ struct chanspy_ds chanspy_ds;
if (ast_test_flag(flags, OPTION_EXIT)) {
const char *c;
@@ -428,6 +528,8 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
ast_copy_string(exitcontext, chan->context, sizeof(exitcontext));
}
+ ast_mutex_init(&chanspy_ds.lock);
+
if (chan->_state != AST_STATE_UP)
ast_answer(chan);
@@ -436,6 +538,9 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
waitms = 100;
for (;;) {
+ struct chanspy_ds *peer_chanspy_ds = NULL, *next_chanspy_ds = NULL;
+ struct ast_channel *prev = NULL, *peer = NULL;
+
if (!ast_test_flag(flags, OPTION_QUIET) && num_spyed_upon) {
res = ast_streamfile(chan, "beep", chan->language);
if (!res)
@@ -472,12 +577,13 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
/* reset for the next loop around, unless overridden later */
waitms = 100;
- peer = prev = next = NULL;
num_spyed_upon = 0;
- for (peer = next_channel(peer, spec, exten, context);
- peer;
- prev = peer, peer = next ? next : next_channel(peer, spec, exten, context), next = NULL) {
+ for (peer_chanspy_ds = next_channel(chan, prev, spec, exten, context, &chanspy_ds);
+ peer_chanspy_ds;
+ chanspy_ds_free(peer_chanspy_ds), prev = peer,
+ peer_chanspy_ds = next_chanspy_ds ? next_chanspy_ds :
+ next_channel(chan, prev, spec, exten, context, &chanspy_ds), next_chanspy_ds = NULL) {
const char *group;
int igrp = !mygroup;
char *groups[25];
@@ -490,18 +596,32 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
char *ext;
char *form_enforced;
int ienf = !myenforced;
+ struct ast_channel *peer;
- if (peer == prev)
+ peer = peer_chanspy_ds->chan;
+
+ ast_mutex_unlock(&peer_chanspy_ds->lock);
+
+ if (peer == prev) {
+ ast_channel_unlock(peer);
+ chanspy_ds_free(peer_chanspy_ds);
break;
+ }
- if (peer == chan)
+ if (peer == chan) {
+ ast_channel_unlock(peer);
continue;
+ }
- if (ast_test_flag(flags, OPTION_BRIDGED) && !ast_bridged_channel(peer))
+ if (ast_test_flag(flags, OPTION_BRIDGED) && !ast_bridged_channel(peer)) {
+ ast_channel_unlock(peer);
continue;
+ }
- if (ast_check_hangup(peer) || ast_test_flag(peer, AST_FLAG_SPYING))
+ if (ast_check_hangup(peer) || ast_test_flag(peer, AST_FLAG_SPYING)) {
+ ast_channel_unlock(peer);
continue;
+ }
if (mygroup) {
if ((group = pbx_builtin_getvar_helper(peer, "SPYGROUP"))) {
@@ -518,8 +638,10 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
}
}
- if (!igrp)
+ if (!igrp) {
+ ast_channel_unlock(peer);
continue;
+ }
if (myenforced) {
@@ -559,6 +681,12 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
for (s = peer_name; s < ptr; s++)
*s = tolower(*s);
+
+ /* We have to unlock the peer channel here to avoid a deadlock.
+ * So, when we need it again, we have to lock the datastore and get
+ * the pointer from there to see if the channel is still valid. */
+ ast_channel_unlock(peer);
+ peer = NULL;
if (!ast_test_flag(flags, OPTION_QUIET)) {
if (ast_fileexists(peer_name, NULL, NULL) != -1) {
@@ -574,8 +702,8 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
}
waitms = 5000;
- res = channel_spy(chan, peer, &volfactor, fd, flags, exitcontext);
- num_spyed_upon++;
+ res = channel_spy(chan, peer_chanspy_ds, &volfactor, fd, flags, exitcontext);
+ num_spyed_upon++;
if (res == -1) {
goto exit;
@@ -583,13 +711,28 @@ static int common_exec(struct ast_channel *chan, const struct ast_flags *flags,
res = 0;
goto exit;
} else if (res > 1 && spec) {
+ struct ast_channel *next;
+
snprintf(nameprefix, AST_NAME_STRLEN, "%s/%d", spec, res);
+
if ((next = ast_get_channel_by_name_prefix_locked(nameprefix, strlen(nameprefix)))) {
- ast_channel_unlock(next);
+ peer_chanspy_ds = chanspy_ds_free(peer_chanspy_ds);
+ next_chanspy_ds = setup_chanspy_ds(next, &chanspy_ds);
} else {
- /* stay on this channel */
- next = peer;
+ /* stay on this channel, if it is still valid */
+
+ ast_mutex_lock(&peer_chanspy_ds->lock);
+ if (peer_chanspy_ds->chan) {
+ ast_channel_lock(peer_chanspy_ds->chan);
+ next_chanspy_ds = peer_chanspy_ds;
+ peer_chanspy_ds = NULL;
+ } else {
+ /* the channel is gone */
+ ast_mutex_unlock(&peer_chanspy_ds->lock);
+ next_chanspy_ds = NULL;
+ }
}
+
peer = NULL;
}
}
@@ -600,6 +743,8 @@ exit:
ast_channel_setoption(chan, AST_OPTION_TXGAIN, &zero_volume, sizeof(zero_volume), 0);
+ ast_mutex_destroy(&chanspy_ds.lock);
+
return res;
}