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More Avahi changes to fix threading issues (Issue #936)
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@michaelrsweet
michaelrsweet committed May 21, 2024
1 parent a1d9852 commit 0cb7215
Showing 1 changed file with 67 additions and 41 deletions.
108 changes: 67 additions & 41 deletions cups/dnssd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,7 @@ struct _cups_dnssd_s // DNS-SD context

#else // HAVE_AVAHI
cups_mutex_t mutex; // Avahi poll mutex
bool in_callback; // Doing a callback?
AvahiClient *client; // Avahi client connection
AvahiSimplePoll *poll; // Avahi poll class
cups_thread_t monitor; // Monitoring thread
Expand Down Expand Up @@ -772,7 +773,7 @@ cupsDNSSDBrowseNew(
if (!dnssd->browses)
{
// Create an array of browsers...
if ((dnssd->browses = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_func_t)delete_browse)) == NULL)
if ((dnssd->browses = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_cb_t)delete_browse)) == NULL)
{
// Unable to create...
free(browse);
Expand All @@ -796,8 +797,11 @@ cupsDNSSDBrowseNew(
#elif _WIN32

#else // HAVE_AVAHI
DEBUG_puts("2cupsDNSSDBrowseNew: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("2cupsDNSSDBrowseNew: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
}

browse->num_browsers = 1;
browse->browsers[0] = avahi_service_browser_new(dnssd->client, avahi_if_index(if_index), AVAHI_PROTO_UNSPEC, types, /*domain*/NULL, /*flags*/0, (AvahiServiceBrowserCallback)avahi_browse_cb, browse);
Expand All @@ -808,8 +812,11 @@ cupsDNSSDBrowseNew(
free(browse);
browse = NULL;

DEBUG_puts("2cupsDNSSDBrowseNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("2cupsDNSSDBrowseNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);
}

goto done;
}
Expand All @@ -826,10 +833,13 @@ cupsDNSSDBrowseNew(
}
}

DEBUG_puts("2cupsDNSSDBrowseNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("2cupsDNSSDBrowseNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);

avahi_simple_poll_wakeup(dnssd->poll);
avahi_simple_poll_wakeup(dnssd->poll);
}
#endif // HAVE_MDNSRESPONDER

DEBUG_printf("2cupsDNSSDBrowseNew: Adding browse=%p", (void *)browse);
Expand Down Expand Up @@ -940,7 +950,7 @@ cupsDNSSDQueryNew(
{
// Create an array of resolvers...
DEBUG_puts("2cupsDNSSDQueryNew: Creating queries array.");
if ((dnssd->queries = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_func_t)delete_query)) == NULL)
if ((dnssd->queries = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_cb_t)delete_query)) == NULL)
{
// Unable to create...
free(query);
Expand All @@ -964,13 +974,21 @@ cupsDNSSDQueryNew(
#elif _WIN32

#else // HAVE_AVAHI
DEBUG_puts("4avahi_poll_cb: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("4avahi_poll_cb: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
}

query->browser = avahi_record_browser_new(dnssd->client, avahi_if_index(if_index), AVAHI_PROTO_UNSPEC, fullname, AVAHI_DNS_CLASS_IN, rrtype, 0, (AvahiRecordBrowserCallback)avahi_query_cb, query);

DEBUG_puts("4avahi_poll_cb: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("4avahi_poll_cb: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);

avahi_simple_poll_wakeup(dnssd->poll);
}

if (!query->browser)
{
Expand All @@ -979,8 +997,6 @@ cupsDNSSDQueryNew(
query = NULL;
goto done;
}

avahi_simple_poll_wakeup(dnssd->poll);
#endif // HAVE_MDNSRESPONDER

DEBUG_printf("2cupsDNSSDQueryNew: Adding query=%p", (void *)query);
Expand Down Expand Up @@ -1091,23 +1107,6 @@ cupsDNSSDResolveNew(
resolve->cb = resolve_cb;
resolve->cb_data = cb_data;

DEBUG_puts("2cupsDNSSDResolveNew: Write locking rwlock.");
cupsRWLockWrite(&dnssd->rwlock);

if (!dnssd->resolves)
{
// Create an array of resolvers...
DEBUG_puts("2cupsDNSSDResolveNew: Creating resolver array.");
if ((dnssd->resolves = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_func_t)delete_resolve)) == NULL)
{
// Unable to create...
DEBUG_printf("2cupsDNSSDResolveNew: Unable to allocate memory: %s", strerror(errno));
free(resolve);
resolve = NULL;
goto done;
}
}

#ifdef HAVE_MDNSRESPONDER
DNSServiceErrorType error; // Error, if any

Expand All @@ -1123,13 +1122,21 @@ cupsDNSSDResolveNew(
#elif _WIN32

#else // HAVE_AVAHI
DEBUG_puts("2cupsDNSSDResolveNew: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("2cupsDNSSDResolveNew: Locking mutex.");
cupsMutexLock(&dnssd->mutex);
}

resolve->resolver = avahi_service_resolver_new(dnssd->client, avahi_if_index(if_index), AVAHI_PROTO_UNSPEC, name, type, domain, AVAHI_PROTO_UNSPEC, /*flags*/0, (AvahiServiceResolverCallback)avahi_resolve_cb, resolve);

DEBUG_puts("2cupsDNSSDResolveNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);
if (!dnssd->in_callback)
{
DEBUG_puts("2cupsDNSSDResolveNew: Unlocking mutex.");
cupsMutexUnlock(&dnssd->mutex);

avahi_simple_poll_wakeup(dnssd->poll);
}

if (!resolve->resolver)
{
Expand All @@ -1138,18 +1145,33 @@ cupsDNSSDResolveNew(
resolve = NULL;
goto done;
}

avahi_simple_poll_wakeup(dnssd->poll);
#endif // HAVE_MDNSRESPONDER

DEBUG_puts("2cupsDNSSDResolveNew: Write locking rwlock.");
cupsRWLockWrite(&dnssd->rwlock);

if (!dnssd->resolves)
{
// Create an array of resolvers...
DEBUG_puts("2cupsDNSSDResolveNew: Creating resolver array.");
if ((dnssd->resolves = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_cb_t)delete_resolve)) == NULL)
{
// Unable to create...
DEBUG_printf("2cupsDNSSDResolveNew: Unable to allocate memory: %s", strerror(errno));
free(resolve);
resolve = NULL;
goto done;
}
}

DEBUG_printf("2cupsDNSSDResolveNew: Adding resolver %p.", (void *)resolve);
cupsArrayAdd(dnssd->resolves, resolve);

done:

DEBUG_puts("2cupsDNSSDResolveNew: Unlocking rwlock.");
cupsRWUnlock(&dnssd->rwlock);

done:

return (resolve);
}

Expand Down Expand Up @@ -1419,7 +1441,7 @@ cupsDNSSDServiceNew(
if (!dnssd->services)
{
// Create an array of services...
if ((dnssd->services = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_func_t)delete_service)) == NULL)
if ((dnssd->services = cupsArrayNew3(NULL, NULL, NULL, 0, NULL, (cups_afree_cb_t)delete_service)) == NULL)
{
// Unable to create...
free(service->name);
Expand Down Expand Up @@ -2135,7 +2157,9 @@ avahi_browse_cb(
return;
}

browse->dnssd->in_callback = true;
(browse->cb)(browse, browse->cb_data, cups_flags, (uint32_t)if_index, name, type, domain);
browse->dnssd->in_callback = false;
}


Expand Down Expand Up @@ -2338,7 +2362,9 @@ avahi_query_cb(

DEBUG_printf("3avahi_query_cb(..., event=%s, fullname=\"%s\", ..., query=%p)", avahi_events[event], fullname, query);

query->dnssd->in_callback = true;
(query->cb)(query, query->cb_data, event == AVAHI_BROWSER_FAILURE ? CUPS_DNSSD_FLAGS_ERROR : event == AVAHI_BROWSER_NEW ? CUPS_DNSSD_FLAGS_ADD : CUPS_DNSSD_FLAGS_NONE, (uint32_t)if_index, fullname, rrtype, rdata, rdlen);
query->dnssd->in_callback = false;
}


Expand Down

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