From 267a85f9ef709ccbefe5ae0ccbb306bd21921418 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 16 Sep 2021 06:42:07 +0000
Subject: implement output from vfs calls

---
 src/kernel/syscalls.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'src/kernel/syscalls.c')

diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index d39aed9..a5c6f43 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -236,7 +236,16 @@ int _syscall_fs_respond(char __user *buf, int ret) {
 	struct vfs_request *req = process_current->handled_req;
 	if (!req) return -1;
 
-	// TODO copy buffer
+	if (req->output.len > 0 && ret > 0) {
+		// if this vfsop outputs data and ret is positive, it's the length of the buffer
+		// TODO document
+		if (ret > req->output.len)
+			ret = req->output.len; // i'm not handling this in a special way - the fs server can prevent this on its own
+		if (!virt_cpy(req->caller->pages, req->output.buf,
+					process_current->pages, buf, ret)) {
+			// how should this error even be handled? TODO
+		}
+	}
 
 	process_current->handled_req = NULL;
 	vfs_request_finish(req, ret);
-- 
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