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StartDiscovery: Scan for new devices and list it
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/* | |
* bluez_adapter_scan.c - Scan for bluetooth devices | |
* - This example scans for new devices after powering the adapter, if any devices | |
* appeared in /org/hciX/dev_XX_YY_ZZ_AA_BB_CC, it is monitered using "InterfaceAdded" | |
* signal and all the properties of the device is printed | |
* - Scanning continues to run until any device is disappered, this happens after 180 seconds | |
* automatically if the device is not used. | |
* gcc `pkg-config --cflags glib-2.0 gio-2.0` -Wall -Wextra -o ./bin/bluez_adapter_scan ./bluez_adapter_scan.c `pkg-config --libs glib-2.0 gio-2.0` | |
*/ | |
#include <glib.h> | |
#include <gio/gio.h> | |
GDBusConnection *con; | |
static void bluez_property_value(const gchar *key, GVariant *value) | |
{ | |
const gchar *type = g_variant_get_type_string(value); | |
g_print("\t%s : ", key); | |
switch(*type) { | |
case 'o': | |
case 's': | |
g_print("%s\n", g_variant_get_string(value, NULL)); | |
break; | |
case 'b': | |
g_print("%d\n", g_variant_get_boolean(value)); | |
break; | |
case 'u': | |
g_print("%d\n", g_variant_get_uint32(value)); | |
break; | |
case 'a': | |
/* TODO Handling only 'as', but not array of dicts */ | |
if(g_strcmp0(type, "as")) | |
break; | |
g_print("\n"); | |
const gchar *uuid; | |
GVariantIter i; | |
g_variant_iter_init(&i, value); | |
while(g_variant_iter_next(&i, "s", &uuid)) | |
g_print("\t\t%s\n", uuid); | |
break; | |
default: | |
g_print("Other\n"); | |
break; | |
} | |
} | |
static void bluez_device_appeared(GDBusConnection *sig, | |
const gchar *sender_name, | |
const gchar *object_path, | |
const gchar *interface, | |
const gchar *signal_name, | |
GVariant *parameters, | |
gpointer user_data) | |
{ | |
(void)sig; | |
(void)sender_name; | |
(void)object_path; | |
(void)interface; | |
(void)signal_name; | |
(void)user_data; | |
GVariantIter *interfaces; | |
const char *object; | |
const gchar *interface_name; | |
GVariant *properties; | |
g_variant_get(parameters, "(&oa{sa{sv}})", &object, &interfaces); | |
while(g_variant_iter_next(interfaces, "{&s@a{sv}}", &interface_name, &properties)) { | |
if(g_strstr_len(g_ascii_strdown(interface_name, -1), -1, "device")) { | |
g_print("[ %s ]\n", object); | |
const gchar *property_name; | |
GVariantIter i; | |
GVariant *prop_val; | |
g_variant_iter_init(&i, properties); | |
while(g_variant_iter_next(&i, "{&sv}", &property_name, &prop_val)) | |
bluez_property_value(property_name, prop_val); | |
g_variant_unref(prop_val); | |
} | |
g_variant_unref(properties); | |
} | |
return; | |
} | |
#define BT_ADDRESS_STRING_SIZE 18 | |
static void bluez_device_disappeared(GDBusConnection *sig, | |
const gchar *sender_name, | |
const gchar *object_path, | |
const gchar *interface, | |
const gchar *signal_name, | |
GVariant *parameters, | |
gpointer user_data) | |
{ | |
(void)sig; | |
(void)sender_name; | |
(void)object_path; | |
(void)interface; | |
(void)signal_name; | |
GVariantIter *interfaces; | |
const char *object; | |
const gchar *interface_name; | |
char address[BT_ADDRESS_STRING_SIZE] = {'\0'}; | |
g_variant_get(parameters, "(&oas)", &object, &interfaces); | |
while(g_variant_iter_next(interfaces, "s", &interface_name)) { | |
if(g_strstr_len(g_ascii_strdown(interface_name, -1), -1, "device")) { | |
int i; | |
char *tmp = g_strstr_len(object, -1, "dev_") + 4; | |
for(i = 0; *tmp != '\0'; i++, tmp++) { | |
if(*tmp == '_') { | |
address[i] = ':'; | |
continue; | |
} | |
address[i] = *tmp; | |
} | |
g_print("\nDevice %s removed\n", address); | |
g_main_loop_quit((GMainLoop *)user_data); | |
} | |
} | |
return; | |
} | |
static void bluez_signal_adapter_changed(GDBusConnection *conn, | |
const gchar *sender, | |
const gchar *path, | |
const gchar *interface, | |
const gchar *signal, | |
GVariant *params, | |
void *userdata) | |
{ | |
(void)conn; | |
(void)sender; | |
(void)path; | |
(void)interface; | |
(void)userdata; | |
GVariantIter *properties = NULL; | |
GVariantIter *unknown = NULL; | |
const char *iface; | |
const char *key; | |
GVariant *value = NULL; | |
const gchar *signature = g_variant_get_type_string(params); | |
if(g_strcmp0(signature, "(sa{sv}as)") != 0) { | |
g_print("Invalid signature for %s: %s != %s", signal, signature, "(sa{sv}as)"); | |
goto done; | |
} | |
g_variant_get(params, "(&sa{sv}as)", &iface, &properties, &unknown); | |
while(g_variant_iter_next(properties, "{&sv}", &key, &value)) { | |
if(!g_strcmp0(key, "Powered")) { | |
if(!g_variant_is_of_type(value, G_VARIANT_TYPE_BOOLEAN)) { | |
g_print("Invalid argument type for %s: %s != %s", key, | |
g_variant_get_type_string(value), "b"); | |
goto done; | |
} | |
g_print("Adapter is Powered \"%s\"\n", g_variant_get_boolean(value) ? "on" : "off"); | |
} | |
if(!g_strcmp0(key, "Discovering")) { | |
if(!g_variant_is_of_type(value, G_VARIANT_TYPE_BOOLEAN)) { | |
g_print("Invalid argument type for %s: %s != %s", key, | |
g_variant_get_type_string(value), "b"); | |
goto done; | |
} | |
g_print("Adapter scan \"%s\"\n", g_variant_get_boolean(value) ? "on" : "off"); | |
} | |
} | |
done: | |
if(properties != NULL) | |
g_variant_iter_free(properties); | |
if(value != NULL) | |
g_variant_unref(value); | |
} | |
static int bluez_adapter_call_method(const char *method) | |
{ | |
GVariant *result; | |
GError *error = NULL; | |
result = g_dbus_connection_call_sync(con, | |
"org.bluez", | |
/* TODO Find the adapter path runtime */ | |
"/org/bluez/hci0", | |
"org.bluez.Adapter1", | |
method, | |
NULL, | |
NULL, | |
G_DBUS_CALL_FLAGS_NONE, | |
-1, | |
NULL, | |
&error); | |
if(error != NULL) | |
return 1; | |
g_variant_unref(result); | |
return 0; | |
} | |
static int bluez_adapter_set_property(const char *prop, GVariant *value) | |
{ | |
GVariant *result; | |
GError *error = NULL; | |
result = g_dbus_connection_call_sync(con, | |
"org.bluez", | |
"/org/bluez/hci0", | |
"org.freedesktop.DBus.Properties", | |
"Set", | |
g_variant_new("(ssv)", "org.bluez.Adapter1", prop, value), | |
NULL, | |
G_DBUS_CALL_FLAGS_NONE, | |
-1, | |
NULL, | |
&error); | |
if(error != NULL) | |
return 1; | |
g_variant_unref(result); | |
return 0; | |
} | |
int main(void) | |
{ | |
GMainLoop *loop; | |
int rc; | |
guint prop_changed; | |
guint iface_added; | |
guint iface_removed; | |
con = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, NULL); | |
if(con == NULL) { | |
g_print("Not able to get connection to system bus\n"); | |
return 1; | |
} | |
loop = g_main_loop_new(NULL, FALSE); | |
prop_changed = g_dbus_connection_signal_subscribe(con, | |
"org.bluez", | |
"org.freedesktop.DBus.Properties", | |
"PropertiesChanged", | |
NULL, | |
"org.bluez.Adapter1", | |
G_DBUS_SIGNAL_FLAGS_NONE, | |
bluez_signal_adapter_changed, | |
NULL, | |
NULL); | |
iface_added = g_dbus_connection_signal_subscribe(con, | |
"org.bluez", | |
"org.freedesktop.DBus.ObjectManager", | |
"InterfacesAdded", | |
NULL, | |
NULL, | |
G_DBUS_SIGNAL_FLAGS_NONE, | |
bluez_device_appeared, | |
loop, | |
NULL); | |
iface_removed = g_dbus_connection_signal_subscribe(con, | |
"org.bluez", | |
"org.freedesktop.DBus.ObjectManager", | |
"InterfacesRemoved", | |
NULL, | |
NULL, | |
G_DBUS_SIGNAL_FLAGS_NONE, | |
bluez_device_disappeared, | |
loop, | |
NULL); | |
rc = bluez_adapter_set_property("Powered", g_variant_new("b", TRUE)); | |
if(rc) { | |
g_print("Not able to enable the adapter\n"); | |
goto fail; | |
} | |
rc = bluez_adapter_call_method("StartDiscovery"); | |
if(rc) { | |
g_print("Not able to scan for new devices\n"); | |
goto fail; | |
} | |
g_main_loop_run(loop); | |
rc = bluez_adapter_call_method("StopDiscovery"); | |
if(rc) | |
g_print("Not able to stop scanning\n"); | |
g_usleep(100); | |
rc = bluez_adapter_set_property("Powered", g_variant_new("b", FALSE)); | |
if(rc) | |
g_print("Not able to disable the adapter\n"); | |
fail: | |
g_dbus_connection_signal_unsubscribe(con, prop_changed); | |
g_dbus_connection_signal_unsubscribe(con, iface_added); | |
g_dbus_connection_signal_unsubscribe(con, iface_removed); | |
g_object_unref(con); | |
return 0; | |
} |
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I think the
g_variant_unref(prop_val);
on line 77 should be within the while loop. Right now the code may be leaking memory or callingg_variant_unref
on an uninitialized value depending on whether there are more than 1 or 0 properties respectively. See my fork of the gist.