From a0d9a2ebdf8265d40d51f47aa55c627c0e6decd3 Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Thu, 17 Oct 2013 12:03:51 +0800 Subject: [PATCH] ui/common: Don't talloc_free sysinfo and status explicitly Currently, we talloc_free() the sysinfo and status messages in the discover client, right after performing the ui's callback. However, the client may wish to keep a reference to this information beyond the callback invocation. This change introduces a per-message talloc context, which these structures are allocated under. This allows the callbacks to talloc_steal() anything they wish to keep a reference to. Signed-off-by: Jeremy Kerr --- ui/common/discover-client.c | 20 ++++++++++++-------- ui/common/discover-client.h | 9 +++++++++ 2 files changed, 21 insertions(+), 8 deletions(-) diff --git a/ui/common/discover-client.c b/ui/common/discover-client.c index de210bd..b48d541 100644 --- a/ui/common/discover-client.c +++ b/ui/common/discover-client.c @@ -115,7 +115,6 @@ static void update_status(struct discover_client *client, { if (client->ops.update_status) client->ops.update_status(status, client->ops.cb_arg); - talloc_free(status); } static void update_sysinfo(struct discover_client *client, @@ -123,7 +122,6 @@ static void update_sysinfo(struct discover_client *client, { if (client->ops.update_sysinfo) client->ops.update_sysinfo(sysinfo, client->ops.cb_arg); - talloc_free(sysinfo); } static void update_config(struct discover_client *client, @@ -143,16 +141,21 @@ static int discover_client_process(void *arg) struct config *config; struct device *dev; char *dev_id; + void *ctx; int rc; - message = pb_protocol_read_message(client, client->fd); + /* We use a temporary context for processing one message; persistent + * data is re-parented to the client in the callbacks. */ + ctx = talloc_new(client); + + message = pb_protocol_read_message(ctx, client->fd); if (!message) return -1; switch (message->action) { case PB_PROTOCOL_ACTION_DEVICE_ADD: - dev = talloc_zero(client, struct device); + dev = talloc_zero(ctx, struct device); list_init(&dev->boot_options); rc = pb_protocol_deserialise_device(dev, message); @@ -164,7 +167,7 @@ static int discover_client_process(void *arg) device_add(client, dev); break; case PB_PROTOCOL_ACTION_BOOT_OPTION_ADD: - opt = talloc_zero(client, struct boot_option); + opt = talloc_zero(ctx, struct boot_option); rc = pb_protocol_deserialise_boot_option(opt, message); if (rc) { @@ -175,7 +178,7 @@ static int discover_client_process(void *arg) boot_option_add(client, opt); break; case PB_PROTOCOL_ACTION_DEVICE_REMOVE: - dev_id = pb_protocol_deserialise_string(client, message); + dev_id = pb_protocol_deserialise_string(ctx, message); if (!dev_id) { pb_log("%s: no device id?\n", __func__); return 0; @@ -183,7 +186,7 @@ static int discover_client_process(void *arg) device_remove(client, dev_id); break; case PB_PROTOCOL_ACTION_STATUS: - status = talloc_zero(client, struct boot_status); + status = talloc_zero(ctx, struct boot_status); rc = pb_protocol_deserialise_boot_status(status, message); if (rc) { @@ -193,7 +196,7 @@ static int discover_client_process(void *arg) update_status(client, status); break; case PB_PROTOCOL_ACTION_SYSTEM_INFO: - sysinfo = talloc_zero(client, struct system_info); + sysinfo = talloc_zero(ctx, struct system_info); rc = pb_protocol_deserialise_system_info(sysinfo, message); if (rc) { @@ -216,6 +219,7 @@ static int discover_client_process(void *arg) pb_log("%s: unknown action %d\n", __func__, message->action); } + talloc_free(ctx); return 0; } diff --git a/ui/common/discover-client.h b/ui/common/discover-client.h index 6aa0432..fa97fa5 100644 --- a/ui/common/discover-client.h +++ b/ui/common/discover-client.h @@ -18,6 +18,15 @@ struct pb_boot_data { * @device_add: PB_PROTOCOL_ACTION_ADD event callback. * @device_remove: PB_PROTOCOL_ACTION_REMOVE event callback. * @cb_arg: Client managed convenience variable passed to callbacks. + * + * The discover client holds talloc references to the devices (and the + * devices' boot options), so callbacks may store boot options and devices + * as long as the client remains allocated. + * + * The boot_status and system_info structs are allocated by the client, + * and will be free()ed after the callback is invoked. If the callback + * stores these structures for usage beyond the duration of the callback, + * it must talloc_steal() them. */ struct discover_client_ops { -- 2.39.5