From b894b67417487a42ff8554da7e0bf57c67e0d3ba Mon Sep 17 00:00:00 2001
From: David Sheets <dsheets@docker.com>
Date: Thu, 14 Apr 2016 14:57:06 +0100
Subject: [PATCH] transfused: update the event protocol for streaming vsock

Signed-off-by: David Sheets <dsheets@docker.com>
---
 alpine/packages/transfused/transfused.c | 50 ++++++++-----------------
 1 file changed, 15 insertions(+), 35 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index cc6b55c7b..68ada7316 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -180,7 +180,7 @@ uint64_t message_id(uint64_t * message) {
   return message[1];
 }
 
-int read_message(char * descr, int fd, char * buf) {
+int read_message(char * descr, int fd, char * buf, size_t max_read) {
   int read_count;
   size_t nbyte;
   uint32_t len;
@@ -188,14 +188,14 @@ int read_message(char * descr, int fd, char * buf) {
   // TODO: socket read conditions e.g. EAGAIN
   read_count = read(fd, buf, 4);
   if (read_count != 4) {
-    if (read_count < 0) die(1, "", "copy %s: error reading: ", descr);
-    if (read_count == 0) die(1, NULL, "copy %s: EOF reading length", descr);
-    die(1, NULL, "copy %s: short read length %d", descr, read_count);
+    if (read_count < 0) die(1, "", "read %s: error reading: ", descr);
+    if (read_count == 0) die(1, NULL, "read %s: EOF reading length", descr);
+    die(1, NULL, "read %s: short read length %d", descr, read_count);
   }
   len = *((uint32_t *) buf);
-  if (len > IN_BUFSZ)
-    die(1, NULL, "copy %s: message size %d exceeds buffer capacity %d",
-        len, IN_BUFSZ);
+  if (len > max_read)
+    die(1, NULL, "read %s: message size %d exceeds buffer capacity %d",
+        len, max_read);
 
   nbyte = (size_t) (len - 4);
   buf += 4;
@@ -203,8 +203,8 @@ int read_message(char * descr, int fd, char * buf) {
   do {
     // TODO: socket read conditions e.g. EAGAIN
     read_count = read(fd, buf, nbyte);
-    if (read_count < 0) die(1, "", "copy %s: error reading: ", descr);
-    if (read_count == 0) die(1, NULL, "copy %s: EOF reading", descr);
+    if (read_count < 0) die(1, "", "read %s: error reading: ", descr);
+    if (read_count == 0) die(1, NULL, "read %s: EOF reading", descr);
     nbyte -= read_count;
     buf += read_count;
   } while (nbyte != 0);
@@ -222,7 +222,7 @@ void copy_into_fuse(copy_thread_state * copy_state) {
   buf = must_malloc(descr, IN_BUFSZ);
 
   while(1) {
-    read_count = read_message(descr, from, (char *) buf);
+    read_count = read_message(descr, from, (char *) buf, IN_BUFSZ);
 
     write_count = write(to, buf, read_count);
     if (write_count < 0) die(1, "", "copy %s: error writing: ", descr);
@@ -559,13 +559,12 @@ void perform_syscall(connection_t * conn, uint8_t syscall, char path[]) {
 }
 
 void * event_thread(void * connection_ptr) {
-  int read_count, event_len, path_len;
+  int read_count, path_len;
   void * buf;
   connection_t * connection = connection_ptr;
 
   char * path;
   uint8_t syscall;
-  void * msg;
 
   // This thread registers with the file system server as being an
   // fsnotify event actuator. Other mounted file system interactions
@@ -576,36 +575,17 @@ void * event_thread(void * connection_ptr) {
   buf = must_malloc("incoming event buffer", EVENT_BUFSZ);
 
   while(1) {
-    read_count = read(connection->sock, buf, EVENT_BUFSZ);
-    if (read_count < 0) die(1, "event thread: error reading", "");
-
-    event_len = (int) ntohs(*((uint16_t *) buf));
+    read_count = read_message("events", connection->sock, buf, EVENT_BUFSZ);
 
     if (debug)
       thread_log_time(connection, "read %d bytes from event connection\n",
                       read_count);
 
-    // TODO: handle short read
-    if (read_count != event_len) {
-      thread_log_time(connection, "event thread: only read %d of %d\n",
-                      read_count, event_len);
-
-      msg = must_malloc("event hex", read_count * 2 + 1);
-      for (int i = 0; i < read_count; i++) {
-        sprintf(((char *) msg) + (i * 2),"%02x",(int) (((char *) buf)[i]));
-      }
-      ((char *) msg)[read_count * 2] = 0;
-      thread_log_time(connection, "message: %s\n", (char *) msg);
-      free(msg);
-
-      continue;
-    }
-
-    path_len  = (int) ntohs(*(((uint16_t *) buf) + 1));
+    path_len  = (int) ntohs(*(((uint32_t *) buf) + 1));
     // TODO: could check the path length isn't a lie here
-    path = (char *) (((uint8_t *) buf) + 4);
+    path = (char *) (((uint8_t *) buf) + 6);
     // TODO: could check the path is NUL terminated here
-    syscall = *(((uint8_t *) buf) + 4 + path_len);
+    syscall = *(((uint8_t *) buf) + 6 + path_len);
 
     // TODO: should this be in another thread?
     perform_syscall(connection, syscall, path);