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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
This commit is contained in:
rmudgett 2011-02-11 01:02:22 +00:00
parent 86aaf263a6
commit b54eb6e1d8
1 changed files with 82 additions and 4 deletions
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86
channels/chan_dahdi.c
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@ -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;
}