1 files changed, 99 insertions, 0 deletions
diff --git a/hbbpd.c b/hbbpd.c
new file mode 100644
index 0000000..e24cf55
--- /dev/null
+++ b/hbbpd.c
@@ -0,0 +1,99 @@
+/*
+** listener.c -- a datagram sockets "server" demo
+*/
+
+#include "common.h"
+
+int main(int argc, char **argv, char **envp) {
+  int fd;
+  int numbytes;
+  struct sockaddr_storage their_addr;
+  char buf[MAXBUFLEN];
+  socklen_t addr_len;
+
+  /* setup socket, parse cmd line */
+  {
+    struct sockaddr_in6 ba;
+    struct ipv6_mreq ga;
+    if (argc > 2) {
+      fprintf(stderr, "usage: %s [interface]\n", argv[0]);
+      exit(1);
+    }
+    ENP((fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP)), "listener: socket");
+    if (argc == 2) {
+      inet_pton(AF_INET6, "ff02::1", &(ba.sin6_addr));
+      if ((ba.sin6_scope_id = if_nametoindex(argv[1])) == 0) {
+	fprintf(stderr, "interface not found\n");
+	exit(1);
+      }
+    }else{
+      ba.sin6_addr = in6addr_any;
+      ba.sin6_scope_id = 0;
+    }
+    ba.sin6_family = AF_INET6;
+    ba.sin6_port = htons(SERVERPORT);
+    ba.sin6_flowinfo = 0;
+    ENP(bind(fd, (struct sockaddr*) &ba, sizeof ba), "listener: bind");
+  }
+
+  /* daemonize */
+#ifndef DEBUG
+  switch (fork()) {
+  case 0:
+    ENP(setsid(), "setsid");
+    umask(0);
+    break;
+  case -1:
+    perror("fork");
+    exit(1);
+  default:
+    exit(0);
+  }
+#endif
+    
+  /* receive loop */
+  addr_len = sizeof their_addr;
+  while ((numbytes = recvfrom(fd, buf, MAXBUFLEN-1 , 0,
+			      (struct sockaddr *) &their_addr, &addr_len)) != -1) {
+    /* decode packet & launch handler */
+    buf[numbytes] = '\0';
+    char *task = buf,
+      *cl_argv[2] = {task, NULL};
+    if (task[0] == '/' || strstr(task, "..")) {
+      fprintf(stderr, "payload tried directory traversal\n");
+      continue;
+    }
+
+    int fd_payload[2];
+    ENP(pipe(fd_payload), "pipe");
+      
+    switch (fork()) {
+    case 0:
+      /* redirect payload to stdio, leave stdout/err, close the rest */
+      ENP(dup2(fd_payload[0], 0), "dup");
+      ENP(close(fd_payload[0]),  "close");
+      ENP(close(fd_payload[1]),  "close");
+      ENP(close(fd),             "close");
+
+      /* run our task task */
+      execve(task, cl_argv, envp);
+      perror("exec");
+      exit(1);
+    case -1:
+      perror("fork");
+      exit(1);
+    }
+
+    /* write payload to child process; the return value of write is
+       intentionally ignored */
+    int tasklen = strlen(task);
+    if (tasklen < numbytes)
+      write(fd_payload[1], buf + tasklen + 1, numbytes - tasklen - 1);
+    ENP(close(fd_payload[1]), "close");
+    ENP(close(fd_payload[0]), "close");
+    ENP(wait(NULL), "wait");
+  }
+    
+  perror("recvfrom");
+  return 1;
+}