From cbc9aef2953df0245c39ff5894170566ff2a396e Mon Sep 17 00:00:00 2001
From: Alex <alexander3.stratford@live.uwe.ac.uk>
Date: Thu, 5 Dec 2019 10:20:27 +0000
Subject: [PATCH] Added guard condition to seek Fixed guard condition in
filesize to exit properly
---
userprog/syscall_filesize.c | 1 +
userprog/syscall_seek.c | 3 +++
2 files changed, 4 insertions(+)
diff --git a/userprog/syscall_filesize.c b/userprog/syscall_filesize.c
index aff7fe7..7247c5c 100644
--- a/userprog/syscall_filesize.c
+++ b/userprog/syscall_filesize.c
@@ -13,6 +13,7 @@ void syscall_filesize(struct intr_frame *f) {
struct file *file = get_associated_file_pointer(file_descriptor);
if (file == NULL) { // Checking if file is empty or non-existent
f->eax -1; // Returning failure state
+ return;
}
// Using the file_length function in file.h to get the length and store it
int size = file_length(file);
diff --git a/userprog/syscall_seek.c b/userprog/syscall_seek.c
index 9a665a1..e016d6f 100644
--- a/userprog/syscall_seek.c
+++ b/userprog/syscall_seek.c
@@ -17,6 +17,9 @@ void syscall_seek(struct intr_frame *f) {
// pop off second int argument from interrupt frame
unsigned file_pos = *((unsigned*)((int*)f->esp + 2));
struct file *file = get_associated_file_pointer(file_descriptor);
+ if (file == NULL) { // Checking if file is empty or non-existent
+ return;
+ }
// Seek through the file
file_seek(file, file_pos);
}
--
GitLab