README.md

@@ -6,21 +6,27 @@ This is a system utility written in C that allows one to quickly black hole host
 
 # How it Works
 
+The program "blackholes" hosts by setting their entries in /etc/hosts to be
+`0.0.0.0` so that when one tries to resolve the host in the browser the host will
+resolve to `0.0.0.0`.
+
 The program will wake up in a configurable timeframe continuously, reading a config file into memory and making appropriate changes to the /etc/hosts based on what it reads from the config.
 
+Starting the program like this allows for the program to run as a daemon:
+
+```bash
+sudo hb -period <wakeup period> -config <path/to/config> -daemon
+```
+
+The config file at the moment is just a newline separated list of hosts that will
+be added to the /etc/hosts file.
+
 # Motivations
 
 I would like to get better with C, and will be using C much more in the near future. In addition, I have issues with browsing to sites that hurt my productivity and am always on the command line.
 
 # TODO
 
-1. Get  delete working for my /etc/hosts editor.
+- Debug logging
-2. Daemonize this program to be started up by systemd.
+- Systemd unit file for running as a daemon
-    - As part of daemonization, remember and remove added hosts on teardown.
+ 
-    - Can do this with an atexit handler, and a routine in main.
-3. Log dns requests that look at the hosts file -- To see how many go where
-4. As part of daemonization -- only block hosts within a time limit.
-    - Sleep, wakeup, check if time has passed or not, block/unblock host,
-      sleep again.
-5. Read hosts to block from a config file (to not pollute the /etc/hosts file)
-6. Design a unified interface for reading a hosts file. 

main.c

@@ -31,8 +31,7 @@ static char *CONFIG;
  * @param mode whichever mode host file you want to open
  * @return FILE *
  */
-FILE *fopenHostsFile(char *mode)
+FILE *fopenHostsFile(char *mode) {
-{
     return fopen(HOSTFILE, mode);
 }
 
@@ -71,23 +70,22 @@ void modifyHostsFile(char *oldhost, char *newhost, int deleteHost) {
     newHostsFile[strlen(newHostsFile)] = EOF;
 
 //    // Seek to 0
-//    fseek(hostsFile, 0, SEEK_SET);
+    fseek(hostsFile, 0, SEEK_SET);
-    fclose(hostsFile);
+//    fclose(hostsFile);
 
     // If this failed, write an error message to stderr
-//    ONFAILED(0, (fwrite(newHostsFile, sizeof(char), sizeof(newHostsFile), hostsFile))) {
+    ONFAILED(0, (fwrite(newHostsFile, sizeof(char), sizeof(newHostsFile), hostsFile))) {
-//        fprintf(stderr, "Did not write anything!\n");
+        fprintf(stderr, "Did not write anything!\n");
-//    }
+    }
     fprintf(stderr, "New hosts file: \n%s\n", newHostsFile);
-//    fclose(hostsFile);
+    fclose(hostsFile);
 }
 
 
 /**
  * Block a hosts using the hostsFile in FILE
  */
-void blockHost(char *host)
+void blockHost(char *host) {
-{
     FILE *hostsFile = fopenHostsFile("a");
     char blockRule[256];
     sprintf(blockRule, "%s %s\n", blockString, host);