sdbus-server.c

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h> 
#include <errno.h>
#include <systemd/sd-bus.h>

static int method_ping(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
        size_t in_arr_size;
        uint8_t *in_arr = NULL;
        int r;

        /* Read the parameters */
        r = sd_bus_message_read_array(m, 'y', (const void**) &in_arr, &in_arr_size);
        if (r < 0) {
                fprintf(stderr, "Failed to parse parameters: %s\n", strerror(-r));
                return r;
        }

        printf("Received PING - %zu\n", in_arr_size);

        /* Reply with the response */
        return sd_bus_reply_method_return(m, "t", in_arr_size);
}


/* The vtable of our little object, implements the com.nstack.DbusTest interface */
static const sd_bus_vtable calculator_vtable[] = {
        SD_BUS_VTABLE_START(0),
        SD_BUS_METHOD("Ping", "ay", "t", method_ping, SD_BUS_VTABLE_UNPRIVILEGED),
        SD_BUS_VTABLE_END
};

int main(int argc, char *argv[]) {
        sd_bus_slot *slot = NULL;
        sd_bus *bus = NULL;
        int r;

        /* Connect to the user bus this time */
        r = sd_bus_open_user(&bus);
        if (r < 0) {
                fprintf(stderr, "Failed to connect to system bus: %s\n", strerror(-r));
                goto finish;
        }

        /* Install the object */
        r = sd_bus_add_object_vtable(bus,
                                     &slot,
                                     "/com/nstack/DbusTest",  /* object path */
                                     "com.nstack.DbusTest",   /* interface name */
                                     calculator_vtable,
                                     NULL);
        if (r < 0) {
                fprintf(stderr, "Failed to issue method call: %s\n", strerror(-r));
                goto finish;
        }

        /* Take a well-known service name so that clients can find us */
        r = sd_bus_request_name(bus, "com.nstack.DbusTest", 0);
        if (r < 0) {
                fprintf(stderr, "Failed to acquire service name: %s\n", strerror(-r));
                goto finish;
        }

        for (;;) {
                /* Process requests */
                r = sd_bus_process(bus, NULL);
                if (r < 0) {
                        fprintf(stderr, "Failed to process bus: %s\n", strerror(-r));
                        goto finish;
                }
                if (r > 0) /* we processed a request, try to process another one, right-away */
                        continue;

                /* Wait for the next request to process */
                r = sd_bus_wait(bus, (uint64_t) -1);
                if (r < 0) {
                        fprintf(stderr, "Failed to wait on bus: %s\n", strerror(-r));
                        goto finish;
                }
        }

finish:
        sd_bus_slot_unref(slot);
        sd_bus_unref(bus);

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}