read/write payloads via stdio

To allow binary save payload transmission:

- broadcaster reads the payload from stdin if the 2nd param is "-"
- listener passes the payload via stdin to all handlers

3 files changed, 42 insertions, 10 deletions

diff --git a/handler/hello b/handler/hello
index 92e1aa1..68ee5a4 100755
--- a/handler/hello
+++ b/handler/hello
@@ -4,6 +4,8 @@
 
 LOGFILE="./hello.log"
 
-echo "Someone called 'hello $1'!" >> "$LOGFILE"
-
+(   echo -n "Someone called 'hello "
+    cat
+    echo  "'!"
+) >> "$LOGFILE"
 
diff --git a/src/broadcaster.c b/src/broadcaster.c
index c945b91..2f0e194 100644
--- a/src/broadcaster.c
+++ b/src/broadcaster.c
@@ -13,21 +13,36 @@ int main(int argc, char **argv)
 
     /* assemble packet, parse cmd line */
     if (argc < 3 || argc > 4) {
-      fprintf(stderr, "usage: %s interface task [message]\n", argv[0]);
+      fprintf(stderr, "usage: %s interface task [message|-]\n", argv[0]);
       exit(1);
     }
     char buf[MAXBUFLEN],
       *task = argv[2],
       *message = (argc == 4) ? argv[3] : "";
     int task_len = strlen(task),
-      total_len = task_len + 1 + strlen(message);
+      total_len = task_len + 1;
+    strcpy(buf, task);
+    buf[task_len] = 0;
+    if (strcmp(message, "-") == 0) {
+      /* read payload from stdin */
+      int i;
+      while ((MAXBUFLEN-total_len > 0)
+	     && ((i = read(0, &(buf[total_len]), MAXBUFLEN-total_len)) > 0))
+	total_len += i;
+      if (i < 0) {
+	perror("read(stdin)");
+	exit(1);
+      }
+    }else{
+      /* use cmd line for payload */
+      total_len += strlen(message);
+      if (total_len <= MAXBUFLEN)
+	strcpy(buf + 1 + task_len, message);
+    }
     if (total_len > MAXBUFLEN) {
       fprintf(stderr,"payload to long: max %d bytes, was %d\n", MAXBUFLEN, total_len);
       exit(1);
     }
-    strcpy(buf, task);
-    buf[task_len] = 0;
-    strcpy(buf + 1 + task_len, message);
 
     /* setup socket */
     if ((fd = socket(AF_INET6, SOCK_DGRAM, 0)) == -1) {
diff --git a/src/listener.c b/src/listener.c
index 3c2ee64..020b90e 100644
--- a/src/listener.c
+++ b/src/listener.c
@@ -64,16 +64,24 @@ int main(int argc, char **argv, char **envp) {
     /* decode packet & launch handler */
     buf[numbytes] = '\0';
     char *task = buf,
-      *cl_argv[3] = {task, (strlen(task)<numbytes) ? (buf+strlen(task)+1) : NULL, NULL };
-      
+      *cl_argv[2] = {task, NULL};
     if (task[0] == '/' || strstr(task, "..")) {
       fprintf(stderr, "payload tried directory traversal\n");
       continue;
     }
+
+    int fd_payload[2];
+    pipe(fd_payload);
       
     switch (fork()) {
     case 0:
-      close(fd); // close socket handler, leave std io
+      /* redirect payload to stdio, leave stdout/err, close the rest */
+      dup(fd_payload[0], 1);
+      close(fd_payload[0]);
+      close(fd_payload[1]);
+      close(fd);
+
+      /* run our task task */
       execve(task, cl_argv, envp);
       perror("exec");
       exit(1);
@@ -83,6 +91,13 @@ int main(int argc, char **argv, char **envp) {
     default:
       wait();
     }
+
+    /* write payload to child process */
+    int tasklen = strlen(task);
+    if (tasklen < numbytes)
+      write(fd_payload[1], buf + tasklen + 1, numbytes - tasklen - 1);
+    close(fd_payload[1]);
+    close(fd_payload[0]);
   }
     
   perror("recvfrom");