Застревает старт UDS-сервера

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>

void run_server(void);
void run_client(void);

int main(int ac, char *av[]) {
  int server = 0;
  if (ac > 1)
    server = 1;
  if (server) {
    run_server();
  } else {
    run_client();
  }
  return 0;
}

#define SOCKET_NAME "/tmp/testuds"

void run_server(void) {
  char buffer[1024];
  struct sockaddr_un server, client;
  int server_socket = 0;
  int res, name_len, i;

  unlink(SOCKET_NAME);
  server_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
  if (server_socket < 0) {
    printf("server: ERROR: server socket failed\n");
    return;
  }

  server.sun_family = AF_UNIX;
  strcpy(server.sun_path, SOCKET_NAME);
  if (bind(server_socket, (struct sockaddr *)&server, sizeof(server)) < 0) {
    printf("server: ERROR: bind failed \"%s\", errno = %d\n", SOCKET_NAME,
           errno);
    return;
  }

  printf("server: OK\n");

  while (1) {
    name_len = sizeof(client);
    res = recvfrom(server_socket, buffer, sizeof(buffer), 0,
                   (struct sockaddr *)&client, &name_len);
    if (res < 0) {
      printf("server: ERROR: recvfrom failed, errno = %d\n", errno);
      return;
    }
    if (client.sun_family != AF_UNIX) {
      printf("server: unexpected client family %d\n", client.sun_family);
      return;
    }
    printf("server: from client= \"%.*s\", client.sun_path= %s\n", (int)res,
           buffer, client.sun_path);

    strcpy(buffer, "replyfromserver");
    res = sendto(server_socket, buffer, strlen(buffer), 0,
                 (struct sockaddr *)&client, name_len);
    printf("server: reply res= %d\n\n", res);
  }
}

void run_client() {
  char buffer[1024];
  struct sockaddr_un server, client, reply;
  int client_socket = 0;
  int res, name_len;

  client_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
  if (client_socket < 0) {
    printf("client: ERROR: client socket failed, errno = %d\n", errno);
    return;
  }

  client.sun_family = AF_UNIX;
  sprintf(client.sun_path, "/tmp/pid%d", getpid());
  unlink(client.sun_path);

  if (bind(client_socket, (struct sockaddr *)&client, sizeof(client)) < 0) {
    printf("client: ERROR: bind failed \"%s\", errno = %d\n", client.sun_path,
           errno);
    return;
  }

  printf("client: bind OK, \"%s\"\n", client.sun_path);

  server.sun_family = AF_UNIX;
  strcpy(server.sun_path, SOCKET_NAME);
  strcpy(buffer, "datafromclient");
  res = sendto(client_socket, buffer, strlen(buffer), 0,
               (struct sockaddr *)&server, sizeof(server));
  printf("client: sent to server %d bytes, len= %d\n", res, strlen(buffer));

  name_len = sizeof(reply);
  res = recvfrom(client_socket, buffer, sizeof(buffer), 0,
                 (struct sockaddr *)&reply, &name_len);
  if (res < 0) {
    printf("client: ERROR: recvfrom failed, errno = %d\n", errno);
    return;
  }

  printf("client: from server= \"%.*s\"\n", (int)res, buffer);

  strcpy(buffer, "anotherdata");
  res = sendto(client_socket, buffer, strlen(buffer), 0,
               (struct sockaddr *)&server, sizeof(server));
  printf("client: sent to server %d bytes, len= %d\n", res, strlen(buffer));

  name_len = sizeof(reply);
  res = recvfrom(client_socket, buffer, sizeof(buffer), 0,
                 (struct sockaddr *)&reply, &name_len);
  if (res < 0) {
    printf("client: ERROR: recvfrom failed, errno = %d\n", errno);
    return;
  }
  printf("client: second reply= \"%.*s\"\n", (int)res, buffer);

  close(client_socket);
  unlink(client.sun_path);
}