Added shutdown daemon

shutdownd.c

@@ -0,0 +1,97 @@
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+#include <syslog.h>
+#include <stdbool.h>
+#include <mraa.h>
+
+#define GPIO_PIN_12 12
+
+#define MRAA_CHECK_RESULT(X, Y, Z, Q)		\
+  if (X == MRAA_SUCCESS) {			\
+    syslog(LOG_DAEMON | LOG_NOTICE, Y);		\
+  } else {					\
+    syslog(LOG_DAEMON | LOG_ERR, Z);		\
+    if (Q) {					\
+      clean_up();				\
+      exit(EXIT_FAILURE);			\
+    }						\
+  }
+
+void clean_up() {
+  syslog(LOG_DAEMON | LOG_WARNING, "Cleaning up.");
+  closelog();
+}
+
+void sig_handler(int signal) {
+  syslog(LOG_DAEMON | LOG_WARNING, "Shutdown daemon interrupted.");
+  clean_up();
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char ** argv) {
+  int               rv;
+  bool              done = false;
+  sighandler_t      sh;
+  mraa_result_t     mr;
+  mraa_gpio_context pin12;
+
+  // Turn the process into a daemon.
+  rv = daemon(0, 1);
+
+  if (rv != 0) {
+    perror("daemon(0, 1)");
+    return EXIT_FAILURE;
+  }
+
+  // Set SIGINT signal handler
+  sh = signal(SIGINT, sig_handler);
+
+  if (sh == SIG_ERR) {
+    perror("sh = signal(SIGINT, sig_handler)");
+    return EXIT_FAILURE;
+  }
+
+  // Create PID file
+  FILE * pid = fopen("/var/run/shutdown.pid", "w");
+
+  if (pid == NULL) {
+    perror("FILE * pid = fopen(\"/var/run/shutdown.pid\", \"w\")");
+    syslog(LOG_DAEMON | LOG_ERR, "Failed to create PID file.");
+    return EXIT_FAILURE;
+  }
+
+  fprintf(pid, "%d", getpid());
+  fclose(pid);
+  
+  // Open a syslog connection
+  openlog(argv[0], LOG_NDELAY | LOG_PID, LOG_DAEMON);
+  syslog(LOG_DAEMON | LOG_NOTICE, "Started shutdown daemon.");
+
+  // Open PIN 12 as a PULLUP input pin for the push button
+  pin12 = mraa_gpio_init(GPIO_PIN_12);
+  mr = mraa_gpio_dir(pin12, MRAA_GPIO_IN);
+  MRAA_CHECK_RESULT(mr, "Opened push button pin.", "Failed to open push button pin.", true);
+  mr = mraa_gpio_mode(pin12, MRAA_GPIO_PULLUP);
+  MRAA_CHECK_RESULT(mr, "Push button ready.", "Failed to set push button mode.", true);
+
+  // Start pin processing loop
+  while (!done) {    
+    rv = mraa_gpio_read(pin12);
+
+    if (rv == 0) {
+      // If the button is pressed then stop reading and go on with the program
+      syslog(LOG_DAEMON | LOG_NOTICE, "Button push detected.");
+      done = true;
+    }
+  }
+
+  syslog(LOG_DAEMON | LOG_NOTICE, "Finishing.");
+  closelog();
+  execlp("shutdown", "shutdown", "-Ph", "now", (char *)NULL);
+
+  return EXIT_SUCCESS;
+}