commit 80a57afaf29e6ba3fa5fe210e98fc8e97c530e05
Author: Barak Michener <me@barakmich.com>
Date:   Fri Aug 30 19:56:30 2013 -0400

    Initial revision of the daemon

diff --git a/tpm.c b/tpm.c
new file mode 100644
index 0000000..a133682
--- /dev/null
+++ b/tpm.c
@@ -0,0 +1,152 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <time.h>
+#include <unistd.h>
+
+const int kDefaultLengthSecs = 25 * 60;
+
+char* MakeSocketName() {
+  char* username = getenv("USER");
+  char* socket_name =  (char*) calloc(strlen(username) + strlen(P_tmpdir) + 40, sizeof(char));
+  strcat(socket_name, P_tmpdir);
+  strcat(socket_name, "/.tpm-");
+  strcat(socket_name, username);
+  return socket_name;
+}
+
+int DaemonMain(int countdown_time) {
+        /* Our process ID and Session ID */
+        int ok;
+        pid_t pid, sid;
+        struct timespec ts;
+        ts.tv_sec = 0;
+        ts.tv_nsec = 1000 /*micro*/ * 1000 /* milli */ * 50;
+
+        char * socket_name = MakeSocketName();
+    
+        int sock_fd;
+        struct sockaddr_un local, remote;
+
+        if ((sock_fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+          perror("socket");
+          exit(1);
+        }
+        local.sun_family = AF_UNIX;
+        strcpy(local.sun_path, socket_name);
+        unlink(local.sun_path);
+        free(socket_name);
+        int len = strlen(local.sun_path) + sizeof(local.sun_family);
+        if (bind(sock_fd, (struct sockaddr *)&local, len) == -1) {
+          perror("bind");
+          exit(1);
+        }
+        int flags = fcntl(sock_fd,F_GETFL,0);
+        fcntl(sock_fd, F_SETFL, flags | O_NONBLOCK);
+
+        /* Fork off the parent process */
+        pid = fork();
+        if (pid < 0) {
+                exit(EXIT_FAILURE);
+        }
+        /* If we got a good PID, then
+           we can exit the parent process. */
+        if (pid > 0) {
+                exit(EXIT_SUCCESS);
+        }
+
+        /* Change the file mode mask */
+        umask(0);
+                
+        /* Open any logs here */        
+                
+        /* Create a new SID for the child process */
+        sid = setsid();
+        if (sid < 0) {
+                /* Log the failure */
+                exit(EXIT_FAILURE);
+        }
+        
+        
+        /* Change the current working directory */
+        if ((chdir("/")) < 0) {
+                /* Log the failure */
+                exit(EXIT_FAILURE);
+        }
+        
+        /* Close out the standard file descriptors */
+        close(STDIN_FILENO);
+        close(STDOUT_FILENO);
+        close(STDERR_FILENO);
+        
+        if (listen(sock_fd, 5) == -1) {
+          exit(1);
+        }
+
+        
+        /* The Big Loop */
+        int wakeup = 0;
+        struct timeval start_time;
+        ok = gettimeofday(&start_time, NULL);
+        int remote_fd = -1;
+
+        while (!wakeup) {
+           struct timeval current_time;
+           struct timeval diff_time;
+           ok = gettimeofday(&current_time, NULL);
+           timersub(&current_time, &start_time, &diff_time);
+           if (diff_time.tv_sec >= countdown_time) {
+             wakeup = 1;
+             continue;
+           }
+           long remaining_time = (long)countdown_time - diff_time.tv_sec;
+           socklen_t t = sizeof(remote);
+           while ((remote_fd = accept(sock_fd, (struct sockaddr *)&remote, &t)) != -1) {
+             char message[100];
+             int message_len = snprintf(message, 100, "%ld:%02ld", remaining_time / 60, remaining_time % 60);
+             if (send(remote_fd, message, message_len, 0) < 0) {
+              exit(1);
+             }
+             close(remote_fd);
+           }
+           // Make sure it was just EWOULDBLOCK
+           if (errno != EAGAIN && errno != EWOULDBLOCK) {
+             exit(1);
+           }
+           ok = nanosleep(&ts, NULL);
+        }
+   unlink(local.sun_path);
+   exit(EXIT_SUCCESS);
+}
+
+int main(int argc, char** argv) {
+    int c;
+    int countdown_time = kDefaultLengthSecs;
+    while ( (c = getopt(argc, argv, "bsm")) != -1) {
+        switch (c) {
+        case 's':
+            countdown_time = atoi(optarg);
+            break;
+        case 'm':
+            countdown_time = atoi(optarg) * 60;
+            break;
+        }
+    }
+    if (optind < argc) {
+        char* command = argv[optind];
+        if (strcmp(command, "start") == 0) {
+          DaemonMain(countdown_time);
+        }
+    } else {
+      return DaemonMain(25);
+    }
+    exit (0);   
+}