ioctl: don't set outbufsz when not needed

libfuse/include/fuse_lowlevel.h

@@ -888,7 +888,7 @@ struct fuse_lowlevel_ops {
 	 */
 	void (*ioctl) (fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
 		       struct fuse_file_info *fi, unsigned flags,
-		       const void *in_buf, size_t in_bufsz, size_t out_bufsz);
+		       const void *in_buf, uint32_t in_bufsz, uint32_t out_bufsz);
 
 	/**
 	 * Poll for IO readiness
@@ -1286,7 +1286,7 @@ int fuse_reply_ioctl_retry(fuse_req_t req,
  * @param buf buffer containing output data
  * @param size length of output data
  */
-int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, size_t size);
+int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, uint32_t size);
 
 /**
  * Reply to finish ioctl with iov buffer

libfuse/lib/fuse.c

@@ -3896,8 +3896,8 @@ static void fuse_lib_bmap(fuse_req_t req, fuse_ino_t ino, size_t blocksize,
 
 static void fuse_lib_ioctl(fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
 			   struct fuse_file_info *llfi, unsigned int flags,
-			   const void *in_buf, size_t in_bufsz,
-			   size_t out_bufsz_)
+			   const void *in_buf, uint32_t in_bufsz,
+			   uint32_t out_bufsz_)
 {
 	struct fuse *f = req_fuse_prepare(req);
 	struct fuse_intr_data d;

libfuse/lib/fuse_lowlevel.c

@@ -916,23 +916,28 @@ enomem:
 	goto out;
 }
 
-int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, size_t size)
+int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, uint32_t size)
 {
-	struct fuse_ioctl_out arg;
+	int count;
 	struct iovec iov[3];
-	size_t count = 1;
+        struct fuse_ioctl_out arg;
 
-	memset(&arg, 0, sizeof(arg));
-	arg.result = result;
+	arg.result   = result;
+        arg.flags    = 0;
+        arg.in_iovs  = 0;
+        arg.out_iovs = 0;
+
+        count = 1;
 	iov[count].iov_base = &arg;
-	iov[count].iov_len = sizeof(arg);
+	iov[count].iov_len  = sizeof(arg);
 	count++;
 
-	if (size) {
-		iov[count].iov_base = (char *) buf;
-		iov[count].iov_len = size;
-		count++;
-	}
+	if(size)
+          {
+            iov[count].iov_base = (char*)buf;
+            iov[count].iov_len  = size;
+            count++;
+          }
 
 	return send_reply_iov(req, 0, iov, count);
 }

src/fuse_ioctl.cpp

@@ -90,7 +90,8 @@ namespace l
       case FS_IOC_SETVERSION:
         if(endian::is_big() && (sizeof(long) != sizeof(int)))
           return -ENOTTY;
-        *out_bufsz_ = 4;
+        if((data_ != NULL) && (*out_bufsz_ > 4))
+          *out_bufsz_ = 4;
         break;
       }