Subject: Prevent SIGSEGV on handling events for already closed devices.
Bug: http://sourceforge.net/apps/trac/portmedia/ticket/3
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=695842
Bug-Ubuntu: https://launchpad.net/bugs/1073484
Applied-Upstream: yes
---
 pm_linux/pmlinuxalsa.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- portmidi-200.orig/pm_linux/pmlinuxalsa.c
+++ portmidi-200/pm_linux/pmlinuxalsa.c
@@ -193,6 +193,7 @@ static PmError alsa_write_byte(PmInterna
     snd_seq_event_t ev;
     int err;
 
+    if (!desc) return pmBadPtr;
     snd_seq_ev_clear(&ev);
     if (snd_midi_event_encode_byte(desc->parser, byte, &ev) == 1) {
         snd_seq_ev_set_dest(&ev, desc->client, desc->port);
@@ -339,6 +340,7 @@ static PmError alsa_in_close(PmInternal
         pm_hosterror = snd_seq_delete_port(seq, desc->this_port);
     }
     alsa_unuse_queue();
+    midi->descriptor = NULL;
     pm_free(desc);
     if (pm_hosterror) {
         get_alsa_error_text(pm_hosterror_text, PM_HOST_ERROR_MSG_LEN, 
@@ -433,6 +435,7 @@ static PmError alsa_write(PmInternal *mi
 static PmError alsa_write_flush(PmInternal *midi, PmTimestamp timestamp)
 {
     alsa_descriptor_type desc = (alsa_descriptor_type) midi->descriptor;
+    if (!desc) return pmBadPtr;
     VERBOSE printf("snd_seq_drain_output: 0x%x\n", (unsigned int) seq);
     desc->error = snd_seq_drain_output(seq);
     if (desc->error < 0) return pmHostError;
@@ -448,6 +451,7 @@ static PmError alsa_write_short(PmIntern
     PmMessage msg = event->message;
     int i;
     alsa_descriptor_type desc = (alsa_descriptor_type) midi->descriptor;
+    if (!desc) return pmBadPtr;
     for (i = 0; i < bytes; i++) {
         unsigned char byte = msg;
         VERBOSE printf("sending 0x%x\n", byte);
@@ -481,6 +485,10 @@ static void handle_event(snd_seq_event_t
 {
     int device_id = ev->dest.port;
     PmInternal *midi = descriptors[device_id].internalDescriptor;
+    /* The device we received events for might have been closed before we
+       processed them. */
+    if (!midi)
+        return;
     PmEvent pm_ev;
     PmTimeProcPtr time_proc = midi->time_proc;
     PmTimestamp timestamp;
@@ -650,6 +658,7 @@ static PmError alsa_poll(PmInternal *mid
 static unsigned int alsa_has_host_error(PmInternal *midi)
 {
     alsa_descriptor_type desc = (alsa_descriptor_type) midi->descriptor;
+    if (!desc) return 0;
     return desc->error;
 }
 
@@ -657,6 +666,7 @@ static unsigned int alsa_has_host_error(
 static void alsa_get_host_error(PmInternal *midi, char *msg, unsigned int len)
 {
     alsa_descriptor_type desc = (alsa_descriptor_type) midi->descriptor;
+    if (!desc) return;
     int err = (pm_hosterror || desc->error);
     get_alsa_error_text(msg, len, err);
 }