Implement daemon (background) mode by default with optional foreground mode that can be specified on the command line.

3 files changed, 73 insertions, 11 deletions

diff --git a/README b/README
index 9bee79b..c399a62 100644
--- a/README
+++ b/README
@@ -8,6 +8,14 @@ To compile run "make".
 
 To run from the current directory once compiled run "./blabouncer".
 
+Running with command line arguments takes the form:
+./blabouncer [-f] [-c /path/to/blabouncer.conf]
+
+-f sets foreground mode (without this, blabouncer will detach and run in the background as a daemon)
+-c sets a path to a configuration file (this is optional)
+
+Arguments are all optional, but they must be specified in the order shown above.
+
 == Configuration ==
 
 An example configuration file is provided named "blabouncer.conf".
diff --git a/TODO b/TODO
index 7d3fd57..81e62bc 100644
--- a/TODO
+++ b/TODO
@@ -9,4 +9,4 @@ Might need to #include <limits.h> in blabouncer.c to make some operating systems
 
 Send a PING to the server before assuming a timeout is definite.
 
-Implement daemon (background) mode with optional foreground mode.
+Capture Ctrl-C/kill and exit cleanly.
diff --git a/blabouncer.c b/blabouncer.c
index f7e38a1..cd50a0a 100644
--- a/blabouncer.c
+++ b/blabouncer.c
@@ -114,6 +114,7 @@ struct settings {
   char basedir[PATH_MAX];
   int logging;
   int replaylogging;
+  int background; // Whether or not we're running in the background (detached from the terminal as a daemon)
 };
 
 // Structure of connected clients, their socket/file descriptors, their authentication status, and their OpenSSL structures
@@ -2310,7 +2311,10 @@ void dochat(int *serversockfd, int *clientsockfd, struct settings *settings) {
     debugprint(DEBUG_FULL, "top of loop, fdmax %d.\n", fdmax);
     FD_ZERO(&rfds); // clear entries from fd set
 
-    FD_SET(STDIN, &rfds); // add STDIN (fd 0) to read fds to monitor
+     // Add STDIN (fd 0) to read fds to monitor if we're not in background/daemon mode
+    if (!settings->background) {
+      FD_SET(STDIN, &rfds);
+    }
     FD_SET(*serversockfd, &rfds); // add our server network socket to monitor
     FD_SET(*clientsockfd, &rfds); // add our client network socket to monitor
 
@@ -2416,8 +2420,8 @@ void dochat(int *serversockfd, int *clientsockfd, struct settings *settings) {
       }
     }
 
-    // see if there's anything from stdin
-    if (FD_ISSET(STDIN, &rfds)) {
+    // see if there's anything from stdin (unless we're in background/daemon mode)
+    if (!settings->background && FD_ISSET(STDIN, &rfds)) {
       debugprint(DEBUG_FULL, "reading stdin!\n");
 
       char outgoingmsg[MAXDATASIZE]; // String to send to server
@@ -2577,19 +2581,43 @@ int main(int argc, char *argv[]) {
   // Terminate our global debug file string in case it's referenced before being read from file
   debugpath[0] = '\0';
 
-  // Check to see if a configuration file was specified on the command line
-  if (argc == 3) {
+  // Assume background/daemon mode unless specified otherwise on the command line
+  settings.background = 1;
+  // Set configuration file to string to blank for now
+  settings.conffile[0] = '\0';
+
+  // Check to see what was specified on the command line
+  // TODO - Do better command line argument handling (no required order)
+  char helptext[] = "usage: %s [-f] [-c /path/to/blabouncer.conf] (-f for foreground mode)\n";
+  if (argc == 2) {
+    if (strcmp(argv[1], "-f")) {
+      fprintf(stderr, helptext, argv[0]);
+      exit(1);
+    } else {
+      settings.background = 0;
+    }
+  } else if (argc == 3) {
     if (strcmp(argv[1], "-c")) {
-      fprintf(stderr,"usage: %s [-c /path/to/blabouncer.conf]\n", argv[0]);
+      fprintf(stderr, helptext, argv[0]);
       exit(1);
     } else {
       strcpy(settings.conffile, argv[2]);
     }
-  } else if (argc == 2 || argc > 3) {
-    fprintf(stderr,"usage: %s [-c /path/to/blabouncer.conf]\n", argv[0]);
+  } else if (argc == 4) {
+    if (strcmp(argv[1], "-f") || strcmp(argv[2], "-c")) {
+      fprintf(stderr, helptext, argv[0]);
+      exit(1);
+    } else {
+      settings.background = 0;
+      strcpy(settings.conffile, argv[3]);
+    }
+  } else if (argc > 4) {
+    fprintf(stderr, helptext, argv[0]);
     exit(1);
-  } else {
-    // If none provided, set to default
+  }
+
+  // If a configuration file wasn't set on the command line, set it now
+  if (!settings.conffile[0]) {
     snprintf(settings.conffile, PATH_MAX, "%s/.blabouncer/blabouncer.conf", getenv("HOME"));
     // Since this is the default, it might not exist yet, so let's check...
     struct stat st = {0};
@@ -2777,6 +2805,32 @@ int main(int argc, char *argv[]) {
 
   debugprint(DEBUG_SOME, "Using configuration file '%s'.\n", settings.conffile);
 
+  // Unless specified otherwise on the command line, fork to background
+  if (settings.background) {
+    pid_t pid, sid;
+    // Fork from parent
+    if ((pid = fork()) < 0) {
+      printf("Couldn't fork, exiting.\n");
+      debugprint(DEBUG_CRIT, "Couldn't fork, exiting.\n");
+      exit(1);
+    }
+    // Exit parent (pid will be > 0 for the child)
+    if (pid > 0) {
+      exit(0);
+    }
+    umask(0);
+    // Let child become process group leader
+    if ((sid = setsid()) < 0) {
+      printf("Couldn't setsid() child, exiting.\n");
+      debugprint(DEBUG_CRIT, "Couldn't setsid() child, exiting.\n");
+      exit(1);
+    }
+    // In case our cwd changes
+    chdir("/");
+    // TODO - close() STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO here, might need to change fd number
+    // logic/assumptions elsewhere (such as fd 3 being server, fd 4 being clients, etc.)
+  }
+
   // TODO: see if any of this can be shared (i.e. 1. avoid code duplication, and 2. see if variables can be shared between client/server sockets)
 
   // I will try to keep to the notation of "server" meaning the real IRCd, "bouncer" meaning the bouncer, and "client" meaning the real IRC client