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I want to read the data available in Link 2; mainly DNS Servers and DNS Domains. I am not able to figure out how to read those data using c sd bus api.

test@ubuntu:~/Desktop/$systemd-resolve --status
Global
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa

                      ....bla bla.
Link 2 (ens33)
      Current Scopes: DNS
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 49.205.72.130
                      183.82.243.66
          DNS Domain: ~.

If I had to use GetLink method, how could I get the DNS Servers and Domain information?

Needed something similar as below

#define DESTINATION "org.freedesktop.resolve1"
#define PATH        "/org/freedesktop/resolve1"
#define INTERFACE   "org.freedesktop.resolve1.Manager"
#define MEMBER      "GetLink"


static int log_error(int error, const char *message) {
  errno = -error;
  fprintf(stderr, "%s: %m\n", message);
  return error;
}

static int print_unit_path(sd_bus *bus) {
   sd_bus_message *m = NULL;
   sd_bus_error error = SD_BUS_ERROR_NULL;
   sd_bus_message *reply = NULL;
   int r;

  r = sd_bus_message_new_method_call(bus, &m,
                                     DESTINATION, PATH, INTERFACE, MEMBER);
  if (r < 0)
    return log_error(r, "Failed to create bus message");

  r = sd_bus_message_append(m, "i", 2);
  if (r < 0)
    return log_error(r, "Failed to append to bus message");

  r = sd_bus_call(bus, m, -1, &error, &reply);
  if (r < 0)
    return log_error(r, "Call failed");

  const char *ans;
  r = sd_bus_message_read(reply, "o", &ans);
  if (r < 0)
    return log_error(r, "Failed to read reply");

  printf("Link is \"%s\".\n", ans);

}

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

  r = sd_bus_open_system(&bus);
  if (r < 0)
    return log_error(r, "Failed to acquire bus");

  print_unit_path(bus);
}

Output: "/org/freedesktop/resolve1/link/_32"

How do I read the DNS using this link?

Thanks

0 Answers0