implement part of `fs_respond`

7 files changed, 40 insertions, 12 deletions

diff --git a/src/init/main.c b/src/init/main.c
index fa4fda7..de8a599 100644
--- a/src/init/main.c
+++ b/src/init/main.c
@@ -39,10 +39,12 @@ void fs_test(void) {
 		_syscall_fs_wait(back, buf, &len);
 		log("fs_wait returned. ");
 		_syscall_write(tty_fd, buf, len);
+		_syscall_fs_respond(0, NULL, 0);
 	} else {
 		// parent: accesses the fs
 		_syscall_mount(front, argify("/mnt"));
 		log("requesting file. ");
 		file = _syscall_open(argify("/mnt/test"));
+		log("open returned. ");
 	}
 }
diff --git a/src/init/syscalls.c b/src/init/syscalls.c
index 8d5ecf2..50d7067 100644
--- a/src/init/syscalls.c
+++ b/src/init/syscalls.c
@@ -45,6 +45,10 @@ int _syscall_fs_wait(handle_t back, char __user *buf, int __user *len) {
 	return _syscall(_SYSCALL_FS_WAIT, back, (int)buf, (int)len);
 }
 
+int _syscall_fs_respond(int ret, char __user *buf, int len) {
+	return _syscall(_SYSCALL_FS_RESPOND, ret, (int)buf, len);
+}
+
 int _syscall_memflag(void __user *addr, size_t len, int flags) {
 	return _syscall(_SYSCALL_MEMFLAG, (int)addr, len, flags);
 }
diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index 21a1d54..e82971c 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -19,6 +19,7 @@ struct process *process_seed(void) {
 	proc->parent  = NULL;
 	proc->mount   = vfs_mount_seed();
 	proc->id      = next_pid++;
+	proc->handled_req = NULL;
 
 	process_first = proc;
 
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index 595d62c..73a6651 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -36,6 +36,7 @@ struct process {
 			int  __user *len;
 		} awaited_req; // PS_WAITS4REQUEST
 	};
+	struct vfs_request *handled_req;
 
 	struct vfs_mount *mount;
 
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 1180197..b247619 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -222,6 +222,17 @@ int _syscall_fs_wait(handle_t back, char __user *buf, int __user *len) {
 	}
 }
 
+int _syscall_fs_respond(int ret, char __user *buf, int len) {
+	struct vfs_request *req = process_current->handled_req;
+	if (!req) return -1;
+
+	// TODO copy buffer
+
+	process_current->handled_req = NULL;
+	vfs_request_finish(req, ret);
+	return 0;
+}
+
 int _syscall_memflag(void __user *addr, size_t len, int flags) {
 	userptr_t goal = addr + len;
 	struct pagedir *pages = process_current->pages;
@@ -263,6 +274,8 @@ int syscall_handler(int num, int a, int b, int c) {
 			return _syscall_fs_create((userptr_t)a);
 		case _SYSCALL_FS_WAIT:
 			return _syscall_fs_wait(a, (userptr_t)b, (userptr_t)c);
+		case _SYSCALL_FS_RESPOND:
+			return _syscall_fs_respond(a, (userptr_t)b, c);
 		case _SYSCALL_MEMFLAG:
 			return _syscall_memflag((userptr_t)a, b, c);
 		default:
diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index 2ff5d72..a8f2fc0 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -6,23 +6,27 @@
 #include <kernel/vfs/root.h>
 
 // dispatches a VFS operation to the correct process
-_Noreturn void vfs_request_create(struct vfs_request req) {
+_Noreturn void vfs_request_create(struct vfs_request req_) {
+	struct vfs_request *req;
 	int ret;
-	switch (req.backend->type) {
+	process_current->state = PS_WAITS4FS;
+
+	// the request is owned by the caller
+	process_current->pending_req = req_;
+	req = &process_current->pending_req;
+
+	switch (req->backend->type) {
 		case VFS_BACK_ROOT:
-			ret = vfs_root_handler(&req);
-			vfs_request_finish(&req, ret);
+			ret = vfs_root_handler(req);
+			vfs_request_finish(req, ret);
 		case VFS_BACK_USER:
-			process_current->state = PS_WAITS4FS;
-			if (req.backend->handler == NULL) { 
+			if (req->backend->handler == NULL) {
 				// backend isn't ready yet, join the queue
-				assert(req.backend->queue == NULL); // TODO implement a proper queue
-
-				req.backend->queue = process_current;
-				process_current->pending_req = req;
+				assert(req->backend->queue == NULL); // TODO implement a proper queue
+				req->backend->queue = process_current;
 				process_switch_any();
 			} else {
-				vfs_request_pass2handler(&req);
+				vfs_request_pass2handler(req);
 			}
 		default:
 			panic();
@@ -34,7 +38,9 @@ _Noreturn void vfs_request_pass2handler(struct vfs_request *req) {
 	int len;
 	assert(handler);
 	assert(handler->state == PS_WAITS4REQUEST);
+	assert(!handler->handled_req);
 	handler->state = PS_RUNNING;
+	handler->handled_req = req;
 
 	if (!virt_cpy_from(handler->pages,
 				&len, handler->awaited_req.len, sizeof len))
diff --git a/src/shared/syscalls.h b/src/shared/syscalls.h
index d96c8a7..2b5a80e 100644
--- a/src/shared/syscalls.h
+++ b/src/shared/syscalls.h
@@ -22,6 +22,7 @@ enum {
 
 	_SYSCALL_FS_CREATE,
 	_SYSCALL_FS_WAIT,
+	_SYSCALL_FS_RESPOND,
 
 	_SYSCALL_MEMFLAG,
 };
@@ -53,7 +54,7 @@ int _syscall_close(handle_t);
  * @param back a pointer to a handle_t which will store the back pointer
  */
 handle_t _syscall_fs_create(handle_t __user *back);
-
 int _syscall_fs_wait(handle_t back, char __user *buf, int __user *len);
+int _syscall_fs_respond(int ret, char __user *buf, int len);
 
 int _syscall_memflag(void __user *addr, size_t len, int flags);