Initial commit (argument parsing and tcp setup only)

1 files changed, 199 insertions, 0 deletions

diff --git a/risu.c b/risu.c
new file mode 100644
index 0000000..34be02c
--- /dev/null
+++ b/risu.c
@@ -0,0 +1,199 @@
+/* Random Instruction Sequences for Userspace */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <getopt.h>
+
+
+int apprentice_connect(const char *hostname, uint16_t port)
+{
+   /* We are the client end of the TCP connection */
+   int sock;
+   struct sockaddr_in sa;
+   sock = socket(PF_INET, SOCK_STREAM, 0);
+   if (sock < 0)
+   {
+      perror("socket");
+      exit(1);
+   }
+   struct hostent *hostinfo;
+   sa.sin_family = AF_INET;
+   sa.sin_port = htons(port);
+   hostinfo = gethostbyname(hostname);
+   if (!hostinfo)
+   {
+      fprintf(stderr, "Unknown host %s\n", hostname);
+      exit(1);
+   }
+   sa.sin_addr = *(struct in_addr*)hostinfo->h_addr;
+   if (connect(sock, (struct sockaddr*)&sa, sizeof(sa)) < 0)
+   {
+      perror("connect");
+      exit(1);
+   }
+   return sock;
+}
+
+int master_connect(uint16_t port)
+{
+   int sock;
+   struct sockaddr_in sa;
+   sock = socket(PF_INET, SOCK_STREAM, 0);
+   if (sock < 0)
+   {
+      perror("socket");
+      exit(1);
+   }
+   int sora = 1;
+   if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &sora, sizeof(sora)) != 0)
+   {
+      perror("setsockopt(SO_REUSEADDR)");
+      exit(1);
+   }
+
+   sa.sin_family = AF_INET;
+   sa.sin_port = htons(port);
+   sa.sin_addr.s_addr = htonl(INADDR_ANY);
+   if (bind(sock, (struct sockaddr*)&sa, sizeof(sa)) < 0)
+   {
+      perror("bind");
+      exit(1);
+   }
+   if (listen(sock, 1) < 0)
+   {
+      perror("listen");
+      exit(1);
+   }
+   /* Just block until we get a connection */
+   fprintf(stderr, "master: waiting for connection on port %d...\n", port);
+   struct sockaddr_in csa;
+   size_t csasz;
+   int nsock = accept(sock, (struct sockaddr*)&csa, &csasz);
+   if (nsock < 0)
+   {
+      perror("accept");
+      exit(1);
+   }
+   /* We're done with the server socket now */
+   close(sock);
+   return nsock;
+}
+
+int send_stop_test(int sock)
+{
+    const char *stopme = "S";
+    char resp;
+    write(sock, stopme, 1);
+    read(sock, &resp, 1);
+    return resp;
+}
+
+int read_cmd_byte(int sock)
+{
+    char cmd;
+    read(sock, &cmd, 1);
+    return cmd;
+}
+
+void send_response_byte(int sock, int resp)
+{
+    char r = resp;
+    write(sock, &r, 1);
+}
+
+
+int master(int sock)
+{
+    printf("master waiting for data\n");
+    int cmd = read_cmd_byte(sock);
+    printf("Got cmd %c, sending resp 0\n", cmd);
+    send_response_byte(sock, 0);
+    printf("Exiting.\n");
+    return 0;
+    
+}
+
+int apprentice(int sock)
+{
+    printf("requesting stop\n");
+    int resp = send_stop_test(sock);
+    printf("got response %d\n", resp);
+    return resp;
+}
+
+
+int ismaster;
+
+int main(int argc, char **argv)
+{
+   uint16_t port = 0;
+   char *hostname = 0;
+   int sock;
+   
+
+   // TODO clean this up later
+   
+   for (;;)
+   {
+      static struct option longopts[] = 
+         {
+            { "master", no_argument, &ismaster, 1 },
+            { "host", required_argument, 0, 'h' },
+            { "port", required_argument, 0, 'p' },
+            { 0,0,0,0 }
+         };
+      int optidx = 0;
+      int c = getopt_long(argc, argv, "h:p:", longopts, &optidx);
+      if (c == -1)
+      {
+         break;
+      }
+      
+      switch (c)
+      {
+         case 0:
+         {
+            /* flag set by getopt_long, do nothing */
+            break;
+         }
+         case 'h':
+         {
+            hostname = optarg;
+            break;
+         }
+         case 'p':
+         {
+            // FIXME err handling
+            port = strtol(optarg, 0, 10);
+            break;
+         }
+         case '?':
+         {
+            /* error message printed by getopt_long */
+            exit(1);
+         }
+         default:
+            abort();
+      }
+   }
+   if (ismaster)
+   {
+      printf("master port %d\n", port);
+      sock = master_connect(port);
+      return master(sock);
+   }
+   else
+   {
+      printf("apprentice host %s port %d\n", hostname, port);
+      sock = apprentice_connect(hostname, port);
+      return apprentice(sock);
+   }
+}
+
+