From f5b06759464e6b14a114ed74194805cfe66f00c3 Mon Sep 17 00:00:00 2001
From: Alex Stratford <alexander3.stratford@live.uwe.ac.uk>
Date: Mon, 2 Dec 2019 23:18:02 +0000
Subject: [PATCH] Implemented filesize system call Edited system_calls.h to add
common struct
---
userprog/syscall_filesize.c | 11 +++++++++++
userprog/system_calls.h | 11 +++++++++++
2 files changed, 22 insertions(+)
create mode 100644 userprog/syscall_filesize.c
diff --git a/userprog/syscall_filesize.c b/userprog/syscall_filesize.c
new file mode 100644
index 0000000..ab74aad
--- /dev/null
+++ b/userprog/syscall_filesize.c
@@ -0,0 +1,11 @@
+#include "system_calls.h"
+#include "filesys/file.h"
+
+int syscall_filesize(struct intr_frame *file_descriptor) {
+ struct file_map *file_map = get_file(file_descriptor); // Described in system_calls.h, stores file descriptors mapped to files
+ int size;
+ if (file_map == NULL) // Checking if file is empty or non-existent
+ return -1;
+ size = file_length(file_map->file); // Using the file_length function in file.h to get the length and store it
+ return size;
+}
\ No newline at end of file
diff --git a/userprog/system_calls.h b/userprog/system_calls.h
index 8dc87c9..c1b87c7 100644
--- a/userprog/system_calls.h
+++ b/userprog/system_calls.h
@@ -1,5 +1,16 @@
#include "filesys/file.h"
#include "threads/interrupt.h"
+#include "lib/kernel/list.h" // Added due to dependency for list_elem
+#include "filesys/file.c" // Added due to dependency for file
+
+// Maps file descriptions to the associated file structure
+struct file_map
+{
+ struct list_elem list_element; // Defined in list.h
+ int file_descriptor;
+ struct file *file; // Defined in file.c
+};
+
/*
* Terminates Pintos by calling shutdown_power_off()
--
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