From 89c3f3c8f908957a0a878e60535772880ba81d91 Mon Sep 17 00:00:00 2001
From: Joshua Saxby <Joshua2.Saxby@live.uwe.ac.uk>
Date: Mon, 2 Dec 2019 17:51:39 +0000
Subject: [PATCH] Add skeleton of syscall handling implementation
---
Makefile.build | 4 +++
userprog/syscall.c | 56 ++++++++++++++++++++++++++++++++++++++++-
userprog/syscall_exec.c | 6 +++++
userprog/syscall_exit.c | 6 +++++
userprog/syscall_halt.c | 6 +++++
userprog/syscall_wait.c | 6 +++++
userprog/system_calls.h | 35 ++++++++++++++++++++++++++
7 files changed, 118 insertions(+), 1 deletion(-)
create mode 100644 userprog/syscall_exec.c
create mode 100644 userprog/syscall_exit.c
create mode 100644 userprog/syscall_halt.c
create mode 100644 userprog/syscall_wait.c
create mode 100644 userprog/system_calls.h
diff --git a/Makefile.build b/Makefile.build
index 823d5af..0810c23 100644
--- a/Makefile.build
+++ b/Makefile.build
@@ -62,6 +62,10 @@ userprog_SRC += userprog/exception.c # User exception handler.
userprog_SRC += userprog/syscall.c # System call handler.
userprog_SRC += userprog/gdt.c # GDT initialization.
userprog_SRC += userprog/tss.c # TSS management.
+userprog_SRC += userprog/syscall_exec.c
+userprog_SRC += userprog/syscall_exit.c
+userprog_SRC += userprog/syscall_halt.c
+userprog_SRC += userprog/syscall_wait.c
# No virtual memory code yet.
#vm_SRC = vm/file.c # Some file.
diff --git a/userprog/syscall.c b/userprog/syscall.c
index 0463515..210d7a8 100644
--- a/userprog/syscall.c
+++ b/userprog/syscall.c
@@ -1,9 +1,40 @@
#include "userprog/syscall.h"
#include <stdio.h>
#include <syscall-nr.h>
+#include "system_calls.h"
#include "threads/interrupt.h"
#include "threads/thread.h"
+
+/* System call numbers. */
+typedef enum syscall_t {
+ /* Projects 2 and later. */
+ SYSCALL_HALT, /* Halt the operating system. */
+ SYSCALL_EXIT, /* Terminate this process. */
+ SYSCALL_EXEC, /* Start another process. */
+ SYSCALL_WAIT, /* Wait for a child process to die. */
+ SYSCALL_CREATE, /* Create a file. */
+ SYSCALL_REMOVE, /* Delete a file. */
+ SYSCALL_OPEN, /* Open a file. */
+ SYSCALL_FILESIZE, /* Obtain a file's size. */
+ SYSCALL_READ, /* Read from a file. */
+ SYSCALL_WRITE, /* Write to a file. */
+ SYSCALL_SEEK, /* Change position in a file. */
+ SYSCALL_TELL, /* Report current position in a file. */
+ SYSCALL_CLOSE, /* Close a file. */
+
+ /* Project 3 and optionally project 4. */
+ SYSCALL_MMAP, /* Map a file into memory. */
+ SYSCALL_MUNMAP, /* Remove a memory mapping. */
+
+ /* Project 4 only. */
+ SYSCALL_CHDIR, /* Change the current directory. */
+ SYSCALL_MKDIR, /* Create a directory. */
+ SYSCALL_READDIR, /* Reads a directory entry. */
+ SYSCALL_ISDIR, /* Tests if a fd represents a directory. */
+ SYSCALL_INUMBER /* Returns the inode number for a fd. */
+} syscall_t;
+
static void syscall_handler (struct intr_frame *);
void
@@ -16,6 +47,29 @@ syscall_init (void)
static void
syscall_handler (struct intr_frame *f UNUSED)
{
- printf ("system call!\n");
+ /*
+ * the syscall number is addressed by f->esp (pointer to void)
+ * here we cast it to a pointer to int and then dereference that
+ * to get the system call number
+ * --Joshua Saxby
+ */
+ int syscall_number = *((int*)f->esp);
+ switch (syscall_number) {
+ case SYSCALL_HALT:
+ syscall_halt(f);
+ break;
+ case SYSCALL_EXIT:
+ syscall_exit(f);
+ break;
+ case SYSCALL_EXEC:
+ syscall_exec(f);
+ break;
+ case SYSCALL_WAIT:
+ syscall_exec(f);
+ break;
+ default:
+ printf ("WARNING: Invalid Syscall (%d)\n", syscall_number);
+ }
+ // TODO: remove this call to exit as we don't want all syscalls to make the thread exit
thread_exit ();
}
diff --git a/userprog/syscall_exec.c b/userprog/syscall_exec.c
new file mode 100644
index 0000000..94a060b
--- /dev/null
+++ b/userprog/syscall_exec.c
@@ -0,0 +1,6 @@
+#include "system_calls.h"
+#include "threads/interrupt.h"
+
+void syscall_exec(struct intr_frame *f) {
+ (void*)0;
+}
\ No newline at end of file
diff --git a/userprog/syscall_exit.c b/userprog/syscall_exit.c
new file mode 100644
index 0000000..07d917f
--- /dev/null
+++ b/userprog/syscall_exit.c
@@ -0,0 +1,6 @@
+#include "system_calls.h"
+#include "threads/interrupt.h"
+
+void syscall_exit(struct intr_frame *f) {
+ (void*)0;
+}
diff --git a/userprog/syscall_halt.c b/userprog/syscall_halt.c
new file mode 100644
index 0000000..1c36076
--- /dev/null
+++ b/userprog/syscall_halt.c
@@ -0,0 +1,6 @@
+#include "system_calls.h"
+#include "threads/interrupt.h"
+
+void syscall_halt(struct intr_frame *f) {
+ (void*)0;
+}
\ No newline at end of file
diff --git a/userprog/syscall_wait.c b/userprog/syscall_wait.c
new file mode 100644
index 0000000..6ef4d52
--- /dev/null
+++ b/userprog/syscall_wait.c
@@ -0,0 +1,6 @@
+#include "system_calls.h"
+#include "threads/interrupt.h"
+
+void syscall_wait(struct intr_frame *f) {
+ (void*)0;
+}
\ No newline at end of file
diff --git a/userprog/system_calls.h b/userprog/system_calls.h
new file mode 100644
index 0000000..5d07273
--- /dev/null
+++ b/userprog/system_calls.h
@@ -0,0 +1,35 @@
+#include "threads/interrupt.h"
+
+/*
+ * Terminates Pintos by calling shutdown_power_off()
+ * (declared in threads/init.h).
+ */
+void syscall_halt(struct intr_frame *f);
+
+/*
+ * Terminates the current user program, returning status to the kernel. If the
+ * process's parent waits for it (see below), this is the status that will be
+ * returned. Conventionally, a status of 0 indicates success and nonzero
+ * values indicate errors.
+ */
+void syscall_exit(struct intr_frame *f);
+
+/*
+ * Runs the executable whose name is given in cmd_line, passing any given
+ * arguments, and returns the new process's program id (pid). Must return pid
+ * -1, which otherwise should not be a valid pid, if the program cannot load or
+ * run for any reason. Thus, the parent process cannot return from the exec
+ * until it knows whether the child process successfully loaded its executable.
+ * You must use appropriate synchronization to ensure this.
+ */
+void syscall_exec(struct intr_frame *f);
+
+/*
+ * Waits for a child process pid and retrieves the child's exit status.
+ */
+void syscall_wait(struct intr_frame *f);
+
+/*
+ * NOTE: There are more system calls implemented by Pintos but we are not
+ * implementing them because the assignment brief does not ask of it.
+ */
\ No newline at end of file
--
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