ttcpd

commit bb728c97c6475bc60f235438cfa445e509e53957
parent 6c2680e277779f86e5a1a25a403b9b2e3bc5c71f
Author: finwo <finwo@pm.me>
Date:   Wed, 15 Nov 2017 21:17:14 +0100

Keep buildfiles simple ; rewritten main code

Diffstat:
D
.dep
 | 
4
----
D
build/50-Makefile
 | 
2
--
M
src/main.c
 | 
90
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------

3 files changed, 72 insertions(+), 24 deletions(-)
diff --git a/.dep b/.dep
@@ -1,4 +0,0 @@
-AUTHOR="Robin Bron"
-NAME="tcpd"
-DEPS=()
-DEPS+=("cdeps/cc-simple")
diff --git a/build/50-Makefile b/build/50-Makefile
@@ -1,2 +0,0 @@
-tcpd: $(OBJS)
-	$(CC) $(OBJS) $(CFLAGS) -o $@
diff --git a/src/main.c b/src/main.c
@@ -7,57 +7,111 @@ extern "C" {
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
+#include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
-int error( char *str ) {
-  printf("%s\n", str);
-  exit(1);
-}
+int main( int argc, char *argv[] ) {
 
-int main( int argc, char **argv ) {
-  if(argc<3) error("Not enough arguments");
-  int i, port = 8080;
+  // Initialize
+  int opt=0,port = 8080;
   char *cmd = 0;
   char **args = 0;
-  for(i=0;i<4&&i<argc;i++) {
-    switch(i) {
-      case 0: break;
-      case 1: port = atoi(*(argv+i)); break;
-      case 2: cmd=*(argv+i); break;
-      case 3: args=argv+i; break;
+
+  // Detect port by environment variables
+  if(getenv("PORT")) {
+    port = atoi(getenv("PORT"));
+  }
+
+  // Parse arguments
+  while((opt = getopt(argc, argv, "c:p:")) != -1) {
+    switch(opt) {
+      case 'c':
+        cmd = optarg;
+        break;
+      case 'p':
+        port = atoi(optarg);
+        break;
+      default:
+        fprintf( stderr, "Usage: %s [-p port] [-c command] [-- arg arg ...]\n", argv[0]);
+        exit(EXIT_FAILURE);
     }
   }
 
+  // Catch arguments to child
+  if(strcmp(argv[optind-1],"--")==0) {
+    args = argv + optind;
+  }
+
+  // Make sure we have a command set
+  if(!cmd) {
+    fprintf( stderr, "Required argument not given: command\n" );
+    exit(EXIT_FAILURE);
+  };
+
+  // Start listening socket
   int sockfd = socket( AF_INET, SOCK_STREAM, 0 );
-  if(sockfd<0) error("socket");
+  if(sockfd<0) {
+    fprintf( stderr, "Could not initialize socket\n" );
+    exit(EXIT_FAILURE);
+  }
+
+  // Setup server address
   struct sockaddr_in saddr, caddr;
   bzero((char *) &saddr, sizeof(saddr));
   saddr.sin_family      = AF_INET;
   saddr.sin_addr.s_addr = INADDR_ANY;
   saddr.sin_port        = htons(port);
 
-  if(bind(sockfd,(struct sockaddr *) &saddr, sizeof(saddr)) < 0) {
-    error("bind");
+  // Bind socket to port
+  if(bind(sockfd,(struct sockaddr *) &saddr, sizeof(saddr))<0) {
+    fprintf( stderr, "Could not bind to port %d\n", port );
+    exit(EXIT_FAILURE);
   }
 
-  listen(sockfd,5);
-  printf("Listening on port %d\n", port);
+  // Start listening
+  if(listen(sockfd,5)) {
+    fprintf( stderr, "Could not start listening\n" );
+    exit(EXIT_FAILURE);
+  } else {
+    printf( "Listening on port %d\n", port );
+  }
+
+  // Prepare for the client
   socklen_t clen = sizeof(caddr);
   int nsock;
+
+  // Start accepting connections
   while( (nsock=accept(sockfd,(struct sockaddr *) &caddr,&clen)) >= 0 ) {
+
+    // Spawn a clone
     if(fork()) {
+
+      // We're the parent, we don't need the socket anymore
       close(nsock);
+
+      // Don't wait for childs, ever
       waitpid(-1,NULL,WNOHANG);
     } else {
+
+      // We're the child, bind the socket to stdio
       dup2(nsock,0);
       dup2(nsock,1);
+
+      // Close the old reference
       close(nsock);
+
+      // Start the given command
       execvp( cmd, args );
+
+      // Being here is a major failure
+      // Simply exit with an error code
       return 3;
     }
   }
 
+  // We should never reach this
+  // Maybe a SIGHUP received?
   return 0;
 }