man/vtable-example.c

   1 /* SPDX-License-Identifier: MIT-0 */
   2
   3 #include <errno.h>
   4 #include <stdbool.h>
   5 #include <stddef.h>
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <systemd/sd-bus.h>
   9
  10 #define _cleanup_(f) __attribute__((cleanup(f)))
  11
  12 #define check(x) ({                             \
  13   int r = (x);                                  \
  14   errno = r < 0 ? -r : 0;                       \
  15   printf(#x ": %m\n");                          \
  16   if (r < 0)                                    \
  17     return EXIT_FAILURE;                        \
  18   })
  19
  20 typedef struct object {
  21   char *name;
  22   uint32_t number;
  23 } object;
  24
  25 static int method(sd_bus_message *m, void *userdata, sd_bus_error *error) {
  26   printf("Got called with userdata=%p\n", userdata);
  27
  28   if (sd_bus_message_is_method_call(m,
  29                                     "org.freedesktop.systemd.VtableExample",
  30                                     "Method4"))
  31     return 1;
  32
  33   const char *string;
  34   check(sd_bus_message_read(m, "s", &string));
  35   check(sd_bus_reply_method_return(m, "s", string));
  36
  37   return 1;
  38 }
  39
  40 static const sd_bus_vtable vtable[] = {
  41         SD_BUS_VTABLE_START(0),
  42         SD_BUS_METHOD(
  43             "Method1", "s", "s", method, 0),
  44         SD_BUS_METHOD_WITH_NAMES_OFFSET(
  45             "Method2",
  46             "so", SD_BUS_PARAM(string) SD_BUS_PARAM(path),
  47             "s", SD_BUS_PARAM(returnstring),
  48             method, offsetof(object, number),
  49             SD_BUS_VTABLE_DEPRECATED),
  50         SD_BUS_METHOD_WITH_ARGS_OFFSET(
  51             "Method3",
  52             SD_BUS_ARGS("s", string, "o", path),
  53             SD_BUS_RESULT("s", returnstring),
  54             method, offsetof(object, number),
  55             SD_BUS_VTABLE_UNPRIVILEGED),
  56         SD_BUS_METHOD_WITH_ARGS(
  57             "Method4",
  58             SD_BUS_NO_ARGS,
  59             SD_BUS_NO_RESULT,
  60             method,
  61             SD_BUS_VTABLE_UNPRIVILEGED),
  62         SD_BUS_SIGNAL(
  63             "Signal1",
  64             "so",
  65             0),
  66         SD_BUS_SIGNAL_WITH_NAMES(
  67             "Signal2",
  68             "so", SD_BUS_PARAM(string) SD_BUS_PARAM(path),
  69             0),
  70         SD_BUS_SIGNAL_WITH_ARGS(
  71             "Signal3",
  72             SD_BUS_ARGS("s", string, "o", path),
  73             0),
  74         SD_BUS_WRITABLE_PROPERTY(
  75             "AutomaticStringProperty", "s", NULL, NULL,
  76             offsetof(object, name),
  77             SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
  78         SD_BUS_WRITABLE_PROPERTY(
  79             "AutomaticIntegerProperty", "u", NULL, NULL,
  80             offsetof(object, number),
  81             SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
  82         SD_BUS_VTABLE_END
  83 };
  84
  85 int main(int argc, char **argv) {
  86   _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
  87
  88   sd_bus_default(&bus);
  89
  90   object object = { .number = 666 };
  91   check((object.name = strdup("name")) != NULL);
  92
  93   check(sd_bus_add_object_vtable(bus, NULL,
  94                                  "/org/freedesktop/systemd/VtableExample",
  95                                  "org.freedesktop.systemd.VtableExample",
  96                                  vtable,
  97                                  &object));
  98
  99   check(sd_bus_request_name(bus,
 100                             "org.freedesktop.systemd.VtableExample",
 101                             0));
 102
 103   for (;;) {
 104     check(sd_bus_wait(bus, UINT64_MAX));
 105     check(sd_bus_process(bus, NULL));
 106   }
 107
 108   check(sd_bus_release_name(bus, "org.freedesktop.systemd.VtableExample"));
 109   free(object.name);
 110
 111   return 0;
 112 }