Add device monitoring feature (hotplug device detection)

Changes:
- Implement libudev 'monitor' interface to detect hotplug devices.
- Forward udev rules as AFB 'subscribe' args to udev_monitoring
objects.
- Filter retrieved property fields through 'mask' argument from
'subscribe' args.
- Generate detached threads (event loop) and data  context for each
client,
so every user can subscribe for device events with their own udev
rules and receive their desired device parameters.

Bug-AGL: SPEC-3512

Signed-off-by: Farshid Monhaseri <monhaseri.f@gmail.com>
Change-Id: I0fc007d9707deaf39d21147aa8240fde302f5f9e

1 files changed, 100 insertions, 33 deletions

diff --git a/src/platform-info-binding.c b/src/platform-info-binding.c
index 5e78fd9..4ae3c70 100644
--- a/src/platform-info-binding.c
+++ b/src/platform-info-binding.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016-2019 "IoT.bzh"
+ * Copyright (C) 2016-2020 "IoT.bzh"
  *
  * Author "Romain Forlot" <romain.forlot@iot.bzh>
  *
@@ -23,6 +23,7 @@
 
 #include <afb/afb-binding.h>
 #include "platform-info-binding.h"
+#include "platform-info-devices.h"
 
 #ifndef PLATFORM_INFO_DIR
 #define PLATFORM_INFO_DIR "/etc/platform-info"
@@ -33,30 +34,42 @@
 #endif
 
 void afv_get(afb_req_t req) {
-	char *json_path = NULL, *full_json_path = NULL;
-	json_object *platform_info = (json_object*) afb_api_get_userdata(req->api);
-	json_object *args = afb_req_json(req), *result = NULL;
-
-	switch (json_object_get_type(args)) {
-		case json_type_null:
-			result = platform_info;
-			break;
-		case json_type_string:
-			full_json_path = strdupa(json_object_get_string(args));
-			result = platform_info;
-			for(json_path = strtok(full_json_path, "."); json_path && *json_path; json_path = strtok(NULL, ".")) {
-				if(! json_object_object_get_ex(result, json_path, &result)) {
-					afb_req_fail(req, "A key hasn't been found in JSON path.", json_path);
-					return;
+	pinfo_api_ctx_t *api_ctx = (pinfo_api_ctx_t*)afb_api_get_userdata(req->api);
+
+	if(api_ctx) {
+		json_object *result = NULL;
+		json_object *args = afb_req_json(req);
+
+		switch (json_object_get_type(args)) {
+			case json_type_null:
+				result = api_ctx->info;
+				break;
+			case json_type_string: {
+				char *json_path = NULL;
+				char *full_json_path = NULL;
+
+				full_json_path = strdupa(json_object_get_string(args));
+				result = api_ctx->info;
+
+				for(json_path = strtok(full_json_path, ".");
+					json_path && *json_path;
+					json_path = strtok(NULL, ".")) {
+					if(! json_object_object_get_ex(result, json_path, &result)) {
+						afb_req_fail(req, "A key hasn't been found in JSON path.", json_path);
+						return;
+					}
 				}
+				break;
 			}
-			break;
-		default:
-			afb_req_fail(req, "Type error", "Argument type is unknown, you must provide a string only");
-			return;
-	}
+			default:
+				afb_req_fail(req, "Type error", "Argument type is unknown, you must provide a string only");
+				return;
+		}
 
-	afb_req_success(req, json_object_get(result), NULL);
+		afb_req_success(req, json_object_get(result), NULL);
+	} else {
+		afb_req_fail(req,"failed","The API contains no context!");
+	}
 }
 
 void afv_set(afb_req_t req) {
@@ -75,27 +88,60 @@ void afv_set(afb_req_t req) {
 	afb_req_success(req, NULL, NULL);
 }
 
-// TODO RFOR: interface with inotify and udev
+// TODO RFOR: interface with inotify
 void afv_unsubscribe(afb_req_t req) {
-	afb_req_success(req, NULL, NULL);
+	pinfo_client_ctx_t* client_ctx = NULL;
+	client_ctx = (pinfo_client_ctx_t*)afb_req_context_get(req);
+
+	if(client_ctx) {
+		const char* event_str = afb_req_value(req,"event");
+
+		if(event_str && strcmp("monitor-devices",event_str) == 0) {
+			afb_req_unsubscribe(req,client_ctx->ev_devs_changed);
+			afb_req_context_clear(req);
+			afb_req_success(req,NULL, NULL);
+		} else {
+			afb_req_fail(req,"failed","No 'event' value provided.");
+		}
+	} else {
+		afb_req_fail(req,"failed","No context available for the client.");
+	}
 }
 
 void afv_subscribe(afb_req_t req) {
-	afb_req_success(req, NULL, NULL);
+	const char* event_str = NULL;
+	event_str = afb_req_value(req,"event");
+
+	if(event_str && strcmp("monitor-devices",event_str) == 0) {
+		if(!afb_req_context_get(req)) {
+			if(pinfo_device_monitor(req) == PINFO_OK) {
+				afb_req_success(req,NULL,NULL);
+			} else {
+				afb_req_fail(req,"failed","Unable to create new context");
+			}
+		} else {
+			afb_req_fail(req,"failed","The client already subscribed.");
+		}
+	} else {
+		afb_req_fail(req,"failed","Invalid event subscription");
+	}
 }
 
-int init(afb_api_t api) {
+static json_object*
+afv_static_info(const char* dir) {
 	struct dirent* dir_ent = NULL;
+	DIR* dir_handle = opendir(dir);
+	json_object* static_info = NULL;
 
-	DIR* dir_handle = opendir(PLATFORM_INFO_DIR);
 	if (! dir_handle) {
 		AFB_ERROR("The directory %s does not exist.", PLATFORM_INFO_DIR);
-		return -1;
+		return NULL;
 	}
-	json_object *json_file = json_object_new_object(), *current_file = NULL;
 
+	static_info = json_object_new_object();
 	while( (dir_ent = readdir(dir_handle)) != NULL) {
 		if(dir_ent->d_type == DT_REG && dir_ent->d_name[0] != '.') {
+			json_object* current_file = NULL;
 			size_t filepath_len = strlen(PLATFORM_INFO_DIR) + strlen(dir_ent->d_name) + 2;
 			char *filepath = alloca(filepath_len);
 
@@ -117,14 +163,35 @@ int init(afb_api_t api) {
 				continue;
 			}
 #endif
-			wrap_json_object_add(json_file, current_file);
-			AFB_DEBUG("JSON loaded: %s", json_object_get_string(json_file));
+			wrap_json_object_add(static_info, current_file);
+			AFB_DEBUG("JSON loaded: %s",
+			json_object_to_json_string_ext(current_file,JSON_C_TO_STRING_PRETTY));
 		}
 	}
 
+	return static_info;
+}
+
+int init(afb_api_t api) {
 	// Initializing the platform_info binding object and associated it to
 	// the api
-	afb_api_set_userdata(api, (void*)json_file);
+	AFB_DEBUG("init() ...");
+	pinfo_api_ctx_t *api_ctx = NULL;
+	int ret = PINFO_OK;
+
+	api_ctx = malloc(sizeof(*api_ctx));
+
+	if(api_ctx) {
+		AFB_DEBUG("init() ... OK");
+		api_ctx->info = afv_static_info(PLATFORM_INFO_DIR);
+		AFB_API_DEBUG(api,"The API static data: %s",
+		json_object_to_json_string_ext(api_ctx->info, JSON_C_TO_STRING_PRETTY));
+		api_ctx->client_count = 0;
+		afb_api_set_userdata(api, (void*)api_ctx);
+	} else {
+		AFB_API_WARNING(api,"Failed to load the static data");
+		ret = PINFO_ERR;
+	}
 
-	return 0;
+	return ret;
 }