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authorrmudgett <rmudgett@f38db490-d61c-443f-a65b-d21fe96a405b>2011-02-11 01:02:22 +0000
committerrmudgett <rmudgett@f38db490-d61c-443f-a65b-d21fe96a405b>2011-02-11 01:02:22 +0000
commitb54eb6e1d80b85a2e56caf6481919dbc79192611 (patch)
tree5bbb8761f832694db175dd11db68557ee2a90e44
parent86aaf263a6fcbfc83ccf2212aa1c2593a58dd091 (diff)
Merged revisions 307623 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r307623 | rmudgett | 2011-02-10 18:29:17 -0600 (Thu, 10 Feb 2011) | 13 lines Reentrancy problem if outgoing call gets different B channel than requested. The chan_dahdi pri_fixup_principle() routine needs to protect the Asterisk channel with the channel lock when it changes the technology private pointer to a new private structure. * Added lock protection while pri_fixup_principle() moves a call from one private structure to another. * Made some pri_fixup_principle() messages more meaningful. Partial backport from v1.8 -r300714. ........ git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.2@307624 f38db490-d61c-443f-a65b-d21fe96a405b
-rw-r--r--channels/chan_dahdi.c86
1 files changed, 82 insertions, 4 deletions
diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index b681ba906..f7bedbca1 100644
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -12502,6 +12502,51 @@ static struct dahdi_pvt *pri_find_crv(struct dahdi_pri *pri, int crv)
#endif /* defined(HAVE_PRI) */
#if defined(HAVE_PRI)
+/*!
+ * \internal
+ * \brief Obtain the DAHDI owner channel lock if the owner exists.
+ * \since 1.8
+ *
+ * \param pri DAHDI PRI control structure.
+ * \param chanpos Channel position in the span.
+ *
+ * \note Assumes the pri->lock is already obtained.
+ * \note Assumes the pri->pvts[chanpos]->lock is already obtained.
+ *
+ * \return Nothing
+ */
+static void sig_pri_lock_owner(struct dahdi_pri *pri, int chanpos)
+{
+ for (;;) {
+ if (!pri->pvts[chanpos]->owner) {
+ /* There is no owner lock to get. */
+ break;
+ }
+ if (!ast_channel_trylock(pri->pvts[chanpos]->owner)) {
+ /* We got the lock */
+ break;
+ }
+ /* We must unlock the PRI to avoid the possibility of a deadlock */
+ ast_mutex_unlock(&pri->lock);
+ DEADLOCK_AVOIDANCE(&pri->pvts[chanpos]->lock);
+ ast_mutex_lock(&pri->lock);
+ }
+}
+#endif /* defined(HAVE_PRI) */
+
+#if defined(HAVE_PRI)
+/*!
+ * \internal
+ * \brief Find the private structure for the libpri call.
+ *
+ * \param pri Span controller structure.
+ * \param channel LibPRI encoded channel ID.
+ *
+ * \note Assumes the pri->lock is already obtained.
+ *
+ * \retval array-index into private pointer array on success.
+ * \retval -1 on error.
+ */
static int pri_find_principle(struct dahdi_pri *pri, int channel)
{
int x;
@@ -12532,6 +12577,19 @@ static int pri_find_principle(struct dahdi_pri *pri, int channel)
#endif /* defined(HAVE_PRI) */
#if defined(HAVE_PRI)
+/*!
+ * \internal
+ * \brief Fixup the private structure associated with the libpri call.
+ *
+ * \param pri Span controller structure.
+ * \param principle Array-index into private array to move call to if not already there.
+ * \param c LibPRI opaque call pointer to find if need to move call.
+ *
+ * \note Assumes the pri->lock is already obtained.
+ *
+ * \retval principle on success.
+ * \retval -1 on error.
+ */
static int pri_fixup_principle(struct dahdi_pri *pri, int principle, q931_call *c)
{
int x;
@@ -12555,13 +12613,27 @@ static int pri_fixup_principle(struct dahdi_pri *pri, int principle, q931_call *
if (principle != x) {
struct dahdi_pvt *new = pri->pvts[principle], *old = pri->pvts[x];
- ast_verb(3, "Moving call from channel %d to channel %d\n",
- old->channel, new->channel);
+ /* Get locks to safely move to the new private structure. */
+ ast_mutex_lock(&old->lock);
+ sig_pri_lock_owner(pri, x);
+ ast_mutex_lock(&new->lock);
+
+ ast_verb(3, "Moving call (%s) from channel %d to %d.\n",
+ old->owner ? old->owner->name : "",
+ old->channel, new->channel);
if (new->owner) {
- ast_log(LOG_WARNING, "Can't fix up channel from %d to %d because %d is already in use\n",
- old->channel, new->channel, new->channel);
+ ast_log(LOG_WARNING,
+ "Can't move call (%s) from channel %d to %d. It is already in use.\n",
+ old->owner ? old->owner->name : "",
+ old->channel, new->channel);
+ ast_mutex_unlock(&new->lock);
+ if (old->owner) {
+ ast_channel_unlock(old->owner);
+ }
+ ast_mutex_unlock(&old->lock);
return -1;
}
+
/* Fix it all up now */
new->owner = old->owner;
old->owner = NULL;
@@ -12599,6 +12671,12 @@ static int pri_fixup_principle(struct dahdi_pri *pri, int principle, q931_call *
/* More stuff to transfer to the new channel. */
new->call_level = old->call_level;
old->call_level = DAHDI_CALL_LEVEL_IDLE;
+
+ ast_mutex_unlock(&old->lock);
+ if (new->owner) {
+ ast_channel_unlock(new->owner);
+ }
+ ast_mutex_unlock(&new->lock);
}
return principle;
}