This patch allocates VMC IDs by finding the first ID not used
instead of using a global variable and incrementing the value
for each channel created.
This solves some potential issues:
- remove the global state potentially making possible
to use multiple SpiceServer on the same process;
- don't potentially overflow the variable. This can happen if
channels are allocated/deallocated multiple times
(currently not done by Qemu).
Signed-off-by: Frediano Ziglio <fziglio@xxxxxxxxxx>
---
server/reds.c | 32 ++++++++++++++++++++++++++++++++
server/reds.h | 1 +
server/spicevmc.c | 10 ++++++++--
3 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/server/reds.c b/server/reds.c
index a738afc3..b6ecc6c6 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -408,6 +408,38 @@ RedChannel *reds_find_channel(RedsState *reds, uint32_t type, uint32_t id)
return NULL;
}
+/* Search for first free channel id for a specific channel type.
+ * Return first id free or <0 if not found. */
+int reds_get_free_channel_id(RedsState *reds, uint32_t type)
+{
+ RedChannel *channel;
+
+ // this mark if some IDs are used.
+ // The size of the array limits the possible id returned but
+ // usually the IDs used for a channel type are not much.
+ bool used_ids[256];
+
+ unsigned n;
+
+ // mark id used for the specific channel type
+ memset(used_ids, 0, sizeof(used_ids));
+ GLIST_FOREACH(reds->channels, RedChannel, channel) {
+ uint32_t this_type, this_id;
+ g_object_get(channel, "channel-type", &this_type, "id", &this_id, NULL);
+ if (this_type == type && this_id < SPICE_N_ELEMENTS(used_ids)) {
+ used_ids[this_id] = true;
+ }
+ }
+
+ // find first ID not marked as used
+ for (n = 0; n < SPICE_N_ELEMENTS(used_ids); ++n) {
+ if (!used_ids[n]) {
+ return n;
+ }
+ }
+ return -1;
+}
+
static void reds_mig_cleanup(RedsState *reds)
{
if (reds->mig_inprogress) {
diff --git a/server/reds.h b/server/reds.h
index ee5a46c0..4f5fc28c 100644
--- a/server/reds.h
+++ b/server/reds.h
@@ -48,6 +48,7 @@ uint32_t reds_get_mm_time(void);
void reds_register_channel(RedsState *reds, RedChannel *channel);
void reds_unregister_channel(RedsState *reds, RedChannel *channel);
RedChannel *reds_find_channel(RedsState *reds, uint32_t type, uint32_t id);
+int reds_get_free_channel_id(RedsState *reds, uint32_t type);
SpiceMouseMode reds_get_mouse_mode(RedsState *reds); // used by inputs_channel
gboolean reds_config_get_agent_mouse(const RedsState *reds); // used by inputs_channel
int reds_has_vdagent(RedsState *reds); // used by inputs channel
diff --git a/server/spicevmc.c b/server/spicevmc.c
index 9305c9b4..08d9954b 100644
--- a/server/spicevmc.c
+++ b/server/spicevmc.c
@@ -272,7 +272,6 @@ red_vmc_channel_finalize(GObject *object)
static RedVmcChannel *red_vmc_channel_new(RedsState *reds, uint8_t channel_type)
{
GType gtype = G_TYPE_NONE;
- static uint8_t id[SPICE_END_CHANNEL] = { 0, };
switch (channel_type) {
case SPICE_CHANNEL_USBREDIR:
@@ -288,11 +287,18 @@ static RedVmcChannel *red_vmc_channel_new(RedsState *reds, uint8_t channel_type)
g_error("Unsupported channel_type for red_vmc_channel_new(): %u", channel_type);
return NULL;
}
+
+ int id = reds_get_free_channel_id(reds, channel_type);
+ if (id < 0) {
+ g_warning("Free ID not found creating new VMC channel");
+ return NULL;
+ }
+
return g_object_new(gtype,
"spice-server", reds,
"core-interface", reds_get_core_interface(reds),
"channel-type", channel_type,
- "id", id[channel_type]++,
+ "id", id,
"handle-acks", FALSE,
"migration-flags",
(SPICE_MIGRATE_NEED_FLUSH | SPICE_MIGRATE_NEED_DATA_TRANSFER),
--
2.13.5
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