libwpa_client monitor example

monitor.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/time.h>
#include <wpa_ctrl.h>

#define CTRL_INTERFACE_DIR "/var/run/wpa_supplicant/wlan0"  

int main(int argc, char *argv[]) {

  int ret;
  int conn_fd = -1;
  fd_set rfds;

  char buf[256];
  size_t len = sizeof(buf) - 1;

  struct timeval tv;
  tv.tv_sec = 5;
  tv.tv_usec = 0;

  struct wpa_ctrl *monitor_conn = NULL;

  monitor_conn = wpa_ctrl_open(CTRL_INTERFACE_DIR);
  if(monitor_conn == NULL) {
    fprintf(stderr, "Open monitor conn failed");
    return -1;
  }

  if(wpa_ctrl_attach(monitor_conn) != 0) {
    fprintf(stderr, "Attach monitor conn failed");
    return -1;
  }

  if((conn_fd = wpa_ctrl_get_fd(monitor_conn)) < 0) {
    fprintf(stderr, "Monitor conn get failed");
    return -1;
  }

  while(monitor_conn) {

    FD_ZERO(&rfds);
    FD_SET(conn_fd, &rfds);
    if(select(conn_fd + 1, &rfds, NULL, NULL, &tv) < 0) {
      break;
    }

    if(FD_ISSET(conn_fd, &rfds)) {
      len = sizeof(buf) - 1;
      ret = wpa_ctrl_recv(monitor_conn, buf, &len);
      if(ret < 0) {
        break;
      }
      buf[len] = '\0';
      printf("%s\n", buf);
    }
  }
  return 0;
}