From 0bf5fdb0e564213159ece8aa9682866d509d6998 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Sun, 3 Nov 2024 22:28:17 +0000
Subject: [PATCH 01/25] Add syscall_function type definition for the different
 syscall handlers, w/ E

---
 src/userprog/syscall.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 370c89b..6f8f660 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -6,6 +6,11 @@
 
 static void syscall_handler (struct intr_frame *);
 
+/* A syscall_function is a function that receives up to 3 arguments, the
+   arguments to the functions are either ints or pointers taking up to 32 bits
+   in size. */
+typedef uintptr_t syscall_function (uintptr_t, uintptr_t, uintptr_t);
+
 void
 syscall_init (void) 
 {

From fa6dac21089676b48b3a4433e55ffa3b022b0f6e Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Sun, 3 Nov 2024 22:34:50 +0000
Subject: [PATCH 02/25] Implement halt system call w/ S.

---
 src/userprog/syscall.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 6f8f660..1d3ef62 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -1,4 +1,5 @@
 #include "userprog/syscall.h"
+#include "devices/shutdown.h"
 #include <stdio.h>
 #include <syscall-nr.h>
 #include "threads/interrupt.h"
@@ -11,6 +12,9 @@ static void syscall_handler (struct intr_frame *);
    in size. */
 typedef uintptr_t syscall_function (uintptr_t, uintptr_t, uintptr_t);
 
+/* System Call Functions */
+static void halt (void);
+
 void
 syscall_init (void) 
 {
@@ -23,3 +27,9 @@ syscall_handler (struct intr_frame *f UNUSED)
   printf ("system call!\n");
   thread_exit ();
 }
+
+static void
+halt (void)
+{
+  shutdown_power_off ();
+}

From c0f85a6bccd74349293151038bbed222b6782a7c Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Sun, 3 Nov 2024 22:36:22 +0000
Subject: [PATCH 03/25] Implement skeleton for exit command w/ S.

---
 src/userprog/syscall.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 1d3ef62..5fec7d3 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -14,6 +14,7 @@ typedef uintptr_t syscall_function (uintptr_t, uintptr_t, uintptr_t);
 
 /* System Call Functions */
 static void halt (void);
+static void exit (int status);
 
 void
 syscall_init (void) 
@@ -33,3 +34,9 @@ halt (void)
 {
   shutdown_power_off ();
 }
+
+static void
+exit (int status)
+{
+  //TODO
+}
\ No newline at end of file

From 62453ef432877ec31ea8b72b810d321260301982 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Sun, 3 Nov 2024 22:54:03 +0000
Subject: [PATCH 04/25] Add a look up table from system call numbers to their
 handler functions, w/ E

---
 src/userprog/syscall.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 5fec7d3..6e7fb17 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -10,12 +10,24 @@ static void syscall_handler (struct intr_frame *);
 /* A syscall_function is a function that receives up to 3 arguments, the
    arguments to the functions are either ints or pointers taking up to 32 bits
    in size. */
-typedef uintptr_t syscall_function (uintptr_t, uintptr_t, uintptr_t);
+typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 
 /* System Call Functions */
 static void halt (void);
 static void exit (int status);
 
+/* A struct defining a pair of a syscall_function along with its arity. */
+typedef struct {
+  syscall_function function;
+  int arity;
+} syscall_arguments;
+
+/* A look-up table for system call functions mapped using their numbers. */
+static const syscall_arguments syscall_lookup[] = {
+  [SYS_HALT] = {(syscall_function) halt, 0},
+  [SYS_EXIT] = {(syscall_function) exit, 1},
+};
+
 void
 syscall_init (void) 
 {

From 87126237ad7ac56cac1062982d05b13c4179690f Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Sun, 3 Nov 2024 23:20:42 +0000
Subject: [PATCH 05/25] Implement function to validate user memory pointers w/
 S.

---
 src/userprog/syscall.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 6e7fb17..9164142 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -1,5 +1,6 @@
 #include "userprog/syscall.h"
 #include "devices/shutdown.h"
+#include "threads/vaddr.h"
 #include <stdio.h>
 #include <syscall-nr.h>
 #include "threads/interrupt.h"
@@ -51,4 +52,15 @@ static void
 exit (int status)
 {
   //TODO
+}
+
+/* A function to validate if a block of memory starting at PTR and of
+   size SIZE bytes is fully contained within user virtual memory.  */
+static void *
+validate_user_pointer (void *ptr, size_t size)
+{
+  if (ptr == NULL || !is_user_vaddr (ptr) || !is_user_vaddr (ptr + size - 1))
+    thread_exit ();
+
+  return ptr;
 }
\ No newline at end of file

From d626b7a392aca74c5327daf493d5183a24571106 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Sun, 3 Nov 2024 23:47:22 +0000
Subject: [PATCH 06/25] Implement basic syscall_handler using the lookup table,
 w/ E

---
 src/userprog/syscall.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 9164142..5e53cd3 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -17,6 +17,8 @@ typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 static void halt (void);
 static void exit (int status);
 
+static void *validate_user_pointer(void *ptr, size_t size);
+
 /* A struct defining a pair of a syscall_function along with its arity. */
 typedef struct {
   syscall_function function;
@@ -29,6 +31,9 @@ static const syscall_arguments syscall_lookup[] = {
   [SYS_EXIT] = {(syscall_function) exit, 1},
 };
 
+static const int lookup_size
+  = sizeof (syscall_lookup) / sizeof (syscall_arguments);
+
 void
 syscall_init (void) 
 {
@@ -36,10 +41,23 @@ syscall_init (void)
 }
 
 static void
-syscall_handler (struct intr_frame *f UNUSED) 
+syscall_handler (struct intr_frame *f)
 {
-  printf ("system call!\n");
-  thread_exit ();
+  validate_user_pointer(f->esp, 1);
+  int syscall_number = *(int *) f->esp;
+
+  if (syscall_number < 0 || syscall_number >= lookup_size)
+    thread_exit ();
+
+  syscall_arguments syscall = syscall_lookup[syscall_number];
+
+  validate_user_pointer (f->esp, syscall.arity);
+  uintptr_t args[3];
+
+  for (int i=0; i < syscall.arity; i++)
+      args[i] = *(uintptr_t *) (f->esp + 1 + i);
+
+  f->eax = syscall.function(args[0], args[1], args[2]);
 }
 
 static void

From ade8faf0f4abe285c103f8085dd2d8fe22c58197 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:20:09 +0000
Subject: [PATCH 07/25] Update syscall to add more comments explaining the
 basic handler

---
 src/userprog/syscall.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 5e53cd3..2926bbd 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -13,24 +13,27 @@ static void syscall_handler (struct intr_frame *);
    in size. */
 typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 
-/* System Call Functions */
+/* System call function prototypes */
 static void halt (void);
 static void exit (int status);
 
 static void *validate_user_pointer(void *ptr, size_t size);
 
-/* A struct defining a pair of a syscall_function along with its arity. */
+/* A struct defining a syscall_function pointer along with its arity. */
 typedef struct {
-  syscall_function function;
-  int arity;
+  syscall_function function;    /* Function pointer. */
+  int arity;                    /* Number of arguments of the function. */
 } syscall_arguments;
 
-/* A look-up table for system call functions mapped using their numbers. */
+/* A look-up table mapping numbers to system call functions with their number of
+   arguments. */
 static const syscall_arguments syscall_lookup[] = {
   [SYS_HALT] = {(syscall_function) halt, 0},
   [SYS_EXIT] = {(syscall_function) exit, 1},
 };
 
+/* The number of syscall functions (i.e, number of elements) within the
+   syscall_lookup table. */
 static const int lookup_size
   = sizeof (syscall_lookup) / sizeof (syscall_arguments);
 
@@ -43,20 +46,24 @@ syscall_init (void)
 static void
 syscall_handler (struct intr_frame *f)
 {
+  /* First, read the system call number from the stack. */
   validate_user_pointer(f->esp, 1);
   int syscall_number = *(int *) f->esp;
 
+  /* Ensures the number corresponds to a system call that can be handled. */
   if (syscall_number < 0 || syscall_number >= lookup_size)
     thread_exit ();
 
   syscall_arguments syscall = syscall_lookup[syscall_number];
 
+  /* Next, read and copy the arguments from the stack pointer. */
   validate_user_pointer (f->esp, syscall.arity);
   uintptr_t args[3];
-
   for (int i=0; i < syscall.arity; i++)
       args[i] = *(uintptr_t *) (f->esp + 1 + i);
 
+  /* Call the function that handles this system call with the arguments. When
+     there is a return value it is stored in f->eax. */
   f->eax = syscall.function(args[0], args[1], args[2]);
 }
 
@@ -67,13 +74,13 @@ halt (void)
 }
 
 static void
-exit (int status)
+exit (int status UNUSED)
 {
   //TODO
 }
 
-/* A function to validate if a block of memory starting at PTR and of
-   size SIZE bytes is fully contained within user virtual memory.  */
+/* Validates if a block of memory starting at PTR and of size SIZE bytes is
+   fully contained within user virtual memory. */
 static void *
 validate_user_pointer (void *ptr, size_t size)
 {

From e718159ed89acf205213caf4cb218a52bb5312d0 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:29:07 +0000
Subject: [PATCH 08/25] Update syscall to use screaming uppercase casing for a
 constant

---
 src/userprog/syscall.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 2926bbd..ddbbd39 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -34,7 +34,7 @@ static const syscall_arguments syscall_lookup[] = {
 
 /* The number of syscall functions (i.e, number of elements) within the
    syscall_lookup table. */
-static const int lookup_size
+static const int LOOKUP_SIZE
   = sizeof (syscall_lookup) / sizeof (syscall_arguments);
 
 void
@@ -51,7 +51,7 @@ syscall_handler (struct intr_frame *f)
   int syscall_number = *(int *) f->esp;
 
   /* Ensures the number corresponds to a system call that can be handled. */
-  if (syscall_number < 0 || syscall_number >= lookup_size)
+  if (syscall_number < 0 || syscall_number >= LOOKUP_SIZE)
     thread_exit ();
 
   syscall_arguments syscall = syscall_lookup[syscall_number];

From 3a258cf064c51f6f69df48a5bf37de9097f337c7 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:38:58 +0000
Subject: [PATCH 09/25] Update validate_user_pointer to perform no memory
 checks when size is 0

---
 src/userprog/syscall.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index ddbbd39..fc8c28e 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -80,11 +80,15 @@ exit (int status UNUSED)
 }
 
 /* Validates if a block of memory starting at PTR and of size SIZE bytes is
-   fully contained within user virtual memory. */
+   fully contained within user virtual memory. Kills the thread (by calling
+   thread_exit) if the memory is invalid. Otherwise, returns the PTR given.
+   If the size is 0, the function does no checks and returns PTR.*/
 static void *
 validate_user_pointer (void *ptr, size_t size)
 {
-  if (ptr == NULL || !is_user_vaddr (ptr) || !is_user_vaddr (ptr + size - 1))
+  if (size > 0 && (ptr == NULL ||
+                   !is_user_vaddr (ptr) ||
+                   !is_user_vaddr (ptr + size - 1)))
     thread_exit ();
 
   return ptr;

From 79f6a8e8080dfd2fc15fd9bd31dc0365600c4600 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:44:55 +0000
Subject: [PATCH 10/25] Fix Bug in syscall handler related to pointer
 arithmetic: add sizeof uintptr_t instead of 1

---
 src/userprog/syscall.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index fc8c28e..e2f0163 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -57,10 +57,11 @@ syscall_handler (struct intr_frame *f)
   syscall_arguments syscall = syscall_lookup[syscall_number];
 
   /* Next, read and copy the arguments from the stack pointer. */
-  validate_user_pointer (f->esp, syscall.arity);
-  uintptr_t args[3];
+  validate_user_pointer (f->esp + sizeof (uintptr_t),
+                         syscall.arity * sizeof (uintptr_t));
+  uintptr_t args[3] = {0};
   for (int i=0; i < syscall.arity; i++)
-      args[i] = *(uintptr_t *) (f->esp + 1 + i);
+      args[i] = *(uintptr_t *) (f->esp + sizeof (uintptr_t) * (i + 1));
 
   /* Call the function that handles this system call with the arguments. When
      there is a return value it is stored in f->eax. */

From 0d057da3dc56dd90fa487df96daf3410ac5ae65d Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:48:36 +0000
Subject: [PATCH 11/25] Refactor syscall to follow PintOS style in adding space
 after after function name in calls

---
 src/userprog/syscall.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index e2f0163..f225b41 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -17,17 +17,19 @@ typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 static void halt (void);
 static void exit (int status);
 
-static void *validate_user_pointer(void *ptr, size_t size);
+static void *validate_user_pointer (void *ptr, size_t size);
 
 /* A struct defining a syscall_function pointer along with its arity. */
-typedef struct {
-  syscall_function function;    /* Function pointer. */
-  int arity;                    /* Number of arguments of the function. */
-} syscall_arguments;
+typedef struct
+  {
+    syscall_function function;    /* Function pointer. */
+    int arity;                    /* Number of arguments of the function. */
+  } syscall_arguments;
 
 /* A look-up table mapping numbers to system call functions with their number of
    arguments. */
-static const syscall_arguments syscall_lookup[] = {
+static const syscall_arguments syscall_lookup[] =
+{
   [SYS_HALT] = {(syscall_function) halt, 0},
   [SYS_EXIT] = {(syscall_function) exit, 1},
 };
@@ -47,7 +49,7 @@ static void
 syscall_handler (struct intr_frame *f)
 {
   /* First, read the system call number from the stack. */
-  validate_user_pointer(f->esp, 1);
+  validate_user_pointer (f->esp, 1);
   int syscall_number = *(int *) f->esp;
 
   /* Ensures the number corresponds to a system call that can be handled. */
@@ -65,7 +67,7 @@ syscall_handler (struct intr_frame *f)
 
   /* Call the function that handles this system call with the arguments. When
      there is a return value it is stored in f->eax. */
-  f->eax = syscall.function(args[0], args[1], args[2]);
+  f->eax = syscall.function (args[0], args[1], args[2]);
 }
 
 static void

From 5e2342fad781a75a70bf6f7bda65d8b2b3d71e1a Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Mon, 4 Nov 2024 00:49:47 +0000
Subject: [PATCH 12/25] Update syscall to make syscall_number an unsigned
 integer instead of an int

---
 src/userprog/syscall.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index f225b41..2b504ec 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -50,10 +50,10 @@ syscall_handler (struct intr_frame *f)
 {
   /* First, read the system call number from the stack. */
   validate_user_pointer (f->esp, 1);
-  int syscall_number = *(int *) f->esp;
+  unsigned syscall_number = *(int *) f->esp;
 
   /* Ensures the number corresponds to a system call that can be handled. */
-  if (syscall_number < 0 || syscall_number >= LOOKUP_SIZE)
+  if (syscall_number >= LOOKUP_SIZE)
     thread_exit ();
 
   syscall_arguments syscall = syscall_lookup[syscall_number];

From 4c27aa020309f756de85b39b9879dfe2f544b123 Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Mon, 4 Nov 2024 00:57:19 +0000
Subject: [PATCH 13/25] Complete syscall lookup table, and syscall stubs and
 skeletons w/ S.

---
 src/userprog/syscall.c | 97 ++++++++++++++++++++++++++++++++++++++++++
 src/userprog/syscall.h |  2 +
 2 files changed, 99 insertions(+)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 5e53cd3..0e0a050 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -16,6 +16,17 @@ typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 /* System Call Functions */
 static void halt (void);
 static void exit (int status);
+static pid_t exec (const char *cmd_line);
+static int wait (pid_t pid);
+static bool file_create (const char *file, unsigned initial_size);
+static bool file_remove (const char *file);
+static int open (const char *file);
+static int filesize (int fd);
+static int read (int fd, void *buffer, unsigned size);
+static int write (int fd, const void *buffer, unsigned size);
+static void seek (int fd, unsigned position);
+static unsigned tell (int fd);
+static void close (int fd);
 
 static void *validate_user_pointer(void *ptr, size_t size);
 
@@ -29,6 +40,17 @@ typedef struct {
 static const syscall_arguments syscall_lookup[] = {
   [SYS_HALT] = {(syscall_function) halt, 0},
   [SYS_EXIT] = {(syscall_function) exit, 1},
+  [SYS_EXEC] = {(syscall_function) exec, 1},
+  [SYS_WAIT] = {(syscall_function) wait, 1},
+  [SYS_CREATE] = {(syscall_function) file_create, 2},
+  [SYS_REMOVE] = {(syscall_function) file_remove, 1},
+  [SYS_OPEN] = {(syscall_function) open, 1},
+  [SYS_FILESIZE] = {(syscall_function) filesize, 1},
+  [SYS_READ] = {(syscall_function) read, 3},
+  [SYS_WRITE] = {(syscall_function) write, 3},
+  [SYS_SEEK] = {(syscall_function) seek, 2},
+  [SYS_TELL] = {(syscall_function) tell, 1},
+  [SYS_CLOSE] = {(syscall_function) close, 1},
 };
 
 static const int lookup_size
@@ -72,6 +94,81 @@ exit (int status)
   //TODO
 }
 
+static pid_t
+exec (const char *cmd_line)
+{
+  //TODO
+  return 0;
+}
+
+static int
+wait (pid_t pid)
+{
+  //TODO
+  return 0;
+}
+
+static bool
+file_create (const char *file, unsigned initial_size)
+{
+  //TODO
+  return 0;
+}
+
+static bool
+file_remove (const char *file)
+{
+  //TODO
+  return 0;
+}
+
+static int
+open (const char *file)
+{
+  //TODO
+  return 0;
+}
+
+static int
+filesize (int fd)
+{
+  //TODO
+  return 0;
+}
+
+static int
+read (int fd, void *buffer, unsigned size)
+{
+  //TODO
+  return 0;
+}
+
+static int
+write (int fd, const void *buffer, unsigned size)
+{
+  //TODO
+  return 0;
+}
+
+static void
+seek (int fd, unsigned position)
+{
+  //TODO
+}
+
+static unsigned
+tell (int fd)
+{
+  //TODO
+  return 0;
+}
+
+static void
+close (int fd)
+{
+  //TODO
+}
+
 /* A function to validate if a block of memory starting at PTR and of
    size SIZE bytes is fully contained within user virtual memory.  */
 static void *
diff --git a/src/userprog/syscall.h b/src/userprog/syscall.h
index 9059096..702a6c7 100644
--- a/src/userprog/syscall.h
+++ b/src/userprog/syscall.h
@@ -1,6 +1,8 @@
 #ifndef USERPROG_SYSCALL_H
 #define USERPROG_SYSCALL_H
 
+typedef int pid_t;
+
 void syscall_init (void);
 
 #endif /* userprog/syscall.h */

From f8e529e87748ae9c0a9c69544259425ca3fbe59b Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Mon, 4 Nov 2024 01:02:04 +0000
Subject: [PATCH 14/25] Add UNUSED tag to system call function skeletons w/ S.

---
 src/userprog/syscall.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 61682aa..fedd1a4 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -105,76 +105,76 @@ exit (int status UNUSED)
 }
 
 static pid_t
-exec (const char *cmd_line)
+exec (const char *cmd_line UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-wait (pid_t pid)
+wait (pid_t pid UNUSED)
 {
   //TODO
   return 0;
 }
 
 static bool
-file_create (const char *file, unsigned initial_size)
+file_create (const char *file UNUSED, unsigned initial_size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static bool
-file_remove (const char *file)
+file_remove (const char *file UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-open (const char *file)
+open (const char *file UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-filesize (int fd)
+filesize (int fd UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-read (int fd, void *buffer, unsigned size)
+read (int fd UNUSED, void *buffer UNUSED, unsigned size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-write (int fd, const void *buffer, unsigned size)
+write (int fd UNUSED, const void *buffer UNUSED, unsigned size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static void
-seek (int fd, unsigned position)
+seek (int fd UNUSED, unsigned position UNUSED)
 {
   //TODO
 }
 
 static unsigned
-tell (int fd)
+tell (int fd UNUSED)
 {
   //TODO
   return 0;
 }
 
 static void
-close (int fd)
+close (int fd UNUSED)
 {
   //TODO
 }

From 2dccd87a76992159c2540604d5f8bd4ec8527982 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Tue, 5 Nov 2024 22:38:09 +0000
Subject: [PATCH 15/25] Update thread to add exit_status, intialised to -1,
 into the thread structure, w/ E

---
 src/threads/thread.c | 2 ++
 src/threads/thread.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/threads/thread.c b/src/threads/thread.c
index 7102ad2..457f7b9 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -659,6 +659,8 @@ init_thread (struct thread *t, const char *name, int nice, int priority,
   t->recent_cpu = recent_cpu;
   t->priority = t->base_priority;
 
+  t->exit_status = -1;
+
   old_level = intr_disable ();
   list_push_back (&all_list, &t->allelem);
   intr_set_level (old_level);
diff --git a/src/threads/thread.h b/src/threads/thread.h
index c7cc364..1c05030 100644
--- a/src/threads/thread.h
+++ b/src/threads/thread.h
@@ -111,6 +111,7 @@ struct thread
     /* Shared between thread.c and synch.c. */
     struct list_elem elem;              /* List element. */
 
+    int exit_status;                    /* Exit Status: 0 = successful exit. */
 
 #ifdef USERPROG
     /* Owned by userprog/process.c. */

From e9c4061531a26621b24e04eac0280384cd509182 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Tue, 5 Nov 2024 22:38:45 +0000
Subject: [PATCH 16/25] Implement the exit system call, w/ E

---
 src/userprog/syscall.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index fedd1a4..5113292 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -99,9 +99,12 @@ halt (void)
 }
 
 static void
-exit (int status UNUSED)
+exit (int status)
 {
-  //TODO
+  /* Sets exit_status of the thread to status. thread_exit () will call
+     process_exit () if user programs are allowed. */
+  thread_current ()->exit_status = status;
+  thread_exit ();
 }
 
 static pid_t

From 421f2c1206933624a58e9ad82bcf51c24e3ffcc4 Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Tue, 5 Nov 2024 22:46:21 +0000
Subject: [PATCH 17/25] Refactor function names and includes in syscall.c to
 avoid conflicts w/ S.

---
 src/userprog/syscall.c | 82 +++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 41 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 5113292..3cb3d69 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -1,10 +1,10 @@
 #include "userprog/syscall.h"
 #include "devices/shutdown.h"
 #include "threads/vaddr.h"
-#include <stdio.h>
-#include <syscall-nr.h>
 #include "threads/interrupt.h"
 #include "threads/thread.h"
+#include <stdio.h>
+#include <syscall-nr.h>
 
 static void syscall_handler (struct intr_frame *);
 
@@ -14,19 +14,19 @@ static void syscall_handler (struct intr_frame *);
 typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
 
 /* System call function prototypes */
-static void halt (void);
-static void exit (int status);
-static pid_t exec (const char *cmd_line);
-static int wait (pid_t pid);
-static bool file_create (const char *file, unsigned initial_size);
-static bool file_remove (const char *file);
-static int open (const char *file);
-static int filesize (int fd);
-static int read (int fd, void *buffer, unsigned size);
-static int write (int fd, const void *buffer, unsigned size);
-static void seek (int fd, unsigned position);
-static unsigned tell (int fd);
-static void close (int fd);
+static void syscall_halt (void);
+static void syscall_exit (int status);
+static pid_t syscall_exec (const char *cmd_line);
+static int syscall_wait (pid_t pid);
+static bool syscall_create (const char *file, unsigned initial_size);
+static bool syscall_remove (const char *file);
+static int syscall_open (const char *file);
+static int syscall_filesize (int fd);
+static int syscall_read (int fd, void *buffer, unsigned size);
+static int syscall_write (int fd, const void *buffer, unsigned size);
+static void syscall_seek (int fd, unsigned position);
+static unsigned syscall_tell (int fd);
+static void syscall_close (int fd);
 
 static void *validate_user_pointer (void *ptr, size_t size);
 
@@ -41,19 +41,19 @@ typedef struct
    arguments. */
 static const syscall_arguments syscall_lookup[] =
 {
-  [SYS_HALT] = {(syscall_function) halt, 0},
-  [SYS_EXIT] = {(syscall_function) exit, 1},
-  [SYS_EXEC] = {(syscall_function) exec, 1},
-  [SYS_WAIT] = {(syscall_function) wait, 1},
-  [SYS_CREATE] = {(syscall_function) file_create, 2},
-  [SYS_REMOVE] = {(syscall_function) file_remove, 1},
-  [SYS_OPEN] = {(syscall_function) open, 1},
-  [SYS_FILESIZE] = {(syscall_function) filesize, 1},
-  [SYS_READ] = {(syscall_function) read, 3},
-  [SYS_WRITE] = {(syscall_function) write, 3},
-  [SYS_SEEK] = {(syscall_function) seek, 2},
-  [SYS_TELL] = {(syscall_function) tell, 1},
-  [SYS_CLOSE] = {(syscall_function) close, 1},
+  [SYS_HALT] = {(syscall_function) syscall_halt, 0},
+  [SYS_EXIT] = {(syscall_function) syscall_exit, 1},
+  [SYS_EXEC] = {(syscall_function) syscall_exec, 1},
+  [SYS_WAIT] = {(syscall_function) syscall_wait, 1},
+  [SYS_CREATE] = {(syscall_function) syscall_create, 2},
+  [SYS_REMOVE] = {(syscall_function) syscall_remove, 1},
+  [SYS_OPEN] = {(syscall_function) syscall_open, 1},
+  [SYS_FILESIZE] = {(syscall_function) syscall_filesize, 1},
+  [SYS_READ] = {(syscall_function) syscall_read, 3},
+  [SYS_WRITE] = {(syscall_function) syscall_write, 3},
+  [SYS_SEEK] = {(syscall_function) syscall_seek, 2},
+  [SYS_TELL] = {(syscall_function) syscall_tell, 1},
+  [SYS_CLOSE] = {(syscall_function) syscall_close, 1},
 };
 
 /* The number of syscall functions (i.e, number of elements) within the
@@ -93,13 +93,13 @@ syscall_handler (struct intr_frame *f)
 }
 
 static void
-halt (void)
+syscall_halt (void)
 {
   shutdown_power_off ();
 }
 
 static void
-exit (int status)
+syscall_exit (int status)
 {
   /* Sets exit_status of the thread to status. thread_exit () will call
      process_exit () if user programs are allowed. */
@@ -108,76 +108,76 @@ exit (int status)
 }
 
 static pid_t
-exec (const char *cmd_line UNUSED)
+syscall_exec (const char *cmd_line UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-wait (pid_t pid UNUSED)
+syscall_wait (pid_t pid UNUSED)
 {
   //TODO
   return 0;
 }
 
 static bool
-file_create (const char *file UNUSED, unsigned initial_size UNUSED)
+syscall_create (const char *file UNUSED, unsigned initial_size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static bool
-file_remove (const char *file UNUSED)
+syscall_remove (const char *file UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-open (const char *file UNUSED)
+syscall_open (const char *file UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-filesize (int fd UNUSED)
+syscall_filesize (int fd UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-read (int fd UNUSED, void *buffer UNUSED, unsigned size UNUSED)
+syscall_read (int fd UNUSED, void *buffer UNUSED, unsigned size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static int
-write (int fd UNUSED, const void *buffer UNUSED, unsigned size UNUSED)
+syscall_write (int fd UNUSED, const void *buffer UNUSED, unsigned size UNUSED)
 {
   //TODO
   return 0;
 }
 
 static void
-seek (int fd UNUSED, unsigned position UNUSED)
+syscall_seek (int fd UNUSED, unsigned position UNUSED)
 {
   //TODO
 }
 
 static unsigned
-tell (int fd UNUSED)
+syscall_tell (int fd UNUSED)
 {
   //TODO
   return 0;
 }
 
 static void
-close (int fd UNUSED)
+syscall_close (int fd UNUSED)
 {
   //TODO
 }

From b3e23eb1ccf68a828175db9cbf1f32f870a652ef Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Tue, 5 Nov 2024 22:48:35 +0000
Subject: [PATCH 18/25] Implement system call wait w/ S.

---
 src/userprog/syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 3cb3d69..6eb1bce 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -3,6 +3,7 @@
 #include "threads/vaddr.h"
 #include "threads/interrupt.h"
 #include "threads/thread.h"
+#include "userprog/process.h"
 #include <stdio.h>
 #include <syscall-nr.h>
 
@@ -115,10 +116,9 @@ syscall_exec (const char *cmd_line UNUSED)
 }
 
 static int
-syscall_wait (pid_t pid UNUSED)
+syscall_wait (pid_t pid)
 {
-  //TODO
-  return 0;
+  return process_wait (pid);
 }
 
 static bool

From 01933cb5de852bcb14b1b225c7512eb0aa8c2255 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Tue, 5 Nov 2024 23:07:07 +0000
Subject: [PATCH 19/25] Implement the write system call, w/ E

---
 src/userprog/syscall.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 6eb1bce..dbcd3b8 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -29,7 +29,7 @@ static void syscall_seek (int fd, unsigned position);
 static unsigned syscall_tell (int fd);
 static void syscall_close (int fd);
 
-static void *validate_user_pointer (void *ptr, size_t size);
+static void *validate_user_pointer (const void *ptr, size_t size);
 
 /* A struct defining a syscall_function pointer along with its arity. */
 typedef struct
@@ -157,10 +157,26 @@ syscall_read (int fd UNUSED, void *buffer UNUSED, unsigned size UNUSED)
 }
 
 static int
-syscall_write (int fd UNUSED, const void *buffer UNUSED, unsigned size UNUSED)
+syscall_write (int fd, const void *buffer, unsigned size)
 {
-  //TODO
-  return 0;
+  /* Only console (fd = 1) or other files, not including STDIN, (fd > 1) are
+     allowed. */
+  if (fd <= 0)
+    return 0;
+
+  validate_user_pointer (buffer, size);
+
+  if (fd == STDOUT_FILENO)
+    {
+      /* Writing to the console. */
+      putbuf (buffer, size);
+      return size;
+    }
+  else
+    {
+      /* Writing to a file. */
+      return 0; // TODO: Implement Write to Files
+    }
 }
 
 static void
@@ -187,7 +203,7 @@ syscall_close (int fd UNUSED)
    thread_exit) if the memory is invalid. Otherwise, returns the PTR given.
    If the size is 0, the function does no checks and returns PTR.*/
 static void *
-validate_user_pointer (void *ptr, size_t size)
+validate_user_pointer (const void *ptr, size_t size)
 {
   if (size > 0 && (ptr == NULL ||
                    !is_user_vaddr (ptr) ||

From f4290c31f325b734b0d1acca1df44b048746b99f Mon Sep 17 00:00:00 2001
From: EDiasAlberto <proxamon1@gmail.com>
Date: Tue, 5 Nov 2024 23:20:18 +0000
Subject: [PATCH 20/25] Implement syscall_read for console input w/ S.

---
 src/userprog/syscall.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index dbcd3b8..6027de2 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -1,5 +1,6 @@
 #include "userprog/syscall.h"
 #include "devices/shutdown.h"
+#include "devices/input.h"
 #include "threads/vaddr.h"
 #include "threads/interrupt.h"
 #include "threads/thread.h"
@@ -150,10 +151,29 @@ syscall_filesize (int fd UNUSED)
 }
 
 static int
-syscall_read (int fd UNUSED, void *buffer UNUSED, unsigned size UNUSED)
+syscall_read (int fd, void *buffer, unsigned size)
 {
-  //TODO
-  return 0;
+  /* Only console (fd = 0) or other files, not including STDOUT, (fd > 1) are
+     allowed. */
+  if (fd < 0 && fd != STDOUT_FILENO)
+    return -1;
+
+  validate_user_pointer (buffer, size);
+
+  if (fd == STDIN_FILENO)
+  {
+    /* Reading from the console. */
+    char *write_buffer = buffer;
+    for (int i = 0; i < size; i++)
+      write_buffer[i] = input_getc ();
+
+    return size;
+  }
+  else
+  {
+    /* Reading from a file. */
+    return 0; // TODO: Implement Write to Files
+  }
 }
 
 static int

From 02fff62ca2dd77af8f59a9630337a0200dae040b Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Tue, 5 Nov 2024 23:24:41 +0000
Subject: [PATCH 21/25] Refactor syscall.c to follow PintOS styling, w/ E

---
 src/userprog/syscall.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 6027de2..1dbe73b 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -161,19 +161,19 @@ syscall_read (int fd, void *buffer, unsigned size)
   validate_user_pointer (buffer, size);
 
   if (fd == STDIN_FILENO)
-  {
-    /* Reading from the console. */
-    char *write_buffer = buffer;
-    for (int i = 0; i < size; i++)
-      write_buffer[i] = input_getc ();
+    {
+      /* Reading from the console. */
+      char *write_buffer = buffer;
+      for (int i = 0; i < size; i++)
+        write_buffer[i] = input_getc ();
 
-    return size;
-  }
+      return size;
+    }
   else
-  {
-    /* Reading from a file. */
-    return 0; // TODO: Implement Write to Files
-  }
+    {
+      /* Reading from a file. */
+      return 0; // TODO: Implement Write to Files
+    }
 }
 
 static int
@@ -231,4 +231,4 @@ validate_user_pointer (const void *ptr, size_t size)
     thread_exit ();
 
   return ptr;
-}
\ No newline at end of file
+}

From 5aac37d1674dfc5b3b32ea5c53b5d80376283914 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Tue, 5 Nov 2024 23:28:17 +0000
Subject: [PATCH 22/25] Add temporary fixes to process_wait and setup stack, w/
 E

---
 src/userprog/process.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/userprog/process.c b/src/userprog/process.c
index 49b9bd5..c9f6339 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -14,6 +14,7 @@
 #include "threads/flags.h"
 #include "threads/init.h"
 #include "threads/interrupt.h"
+#include "threads/synch.h"
 #include "threads/palloc.h"
 #include "threads/thread.h"
 #include "threads/vaddr.h"
@@ -88,7 +89,8 @@ start_process (void *file_name_)
 int
 process_wait (tid_t child_tid UNUSED) 
 {
-  return -1;
+  for (;;)
+    barrier ();
 }
 
 /* Free the current process's resources. */
@@ -451,7 +453,7 @@ setup_stack (void **esp)
     {
       success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage, true);
       if (success)
-        *esp = PHYS_BASE;
+        *esp = PHYS_BASE - 12;
       else
         palloc_free_page (kpage);
     }

From 91cef4d650922cc341b7d40fdd7038cde333039e Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Wed, 6 Nov 2024 15:36:56 +0000
Subject: [PATCH 23/25] Refactor lock release and sema up to remove unnecessary
 code

---
 src/threads/synch.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/threads/synch.c b/src/threads/synch.c
index 09fc71f..d706d19 100644
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -113,28 +113,33 @@ void
 sema_up (struct semaphore *sema)
 {
   enum intr_level old_level;
+  bool thread_unblocked = false; /* Flag to track if any thread was woken up. */
 
   ASSERT (sema != NULL);
 
   old_level = intr_disable ();
   if (!list_empty (&sema->waiters))
-    {
-      /* Enforces wake-up of the highest priority thread waiting for the
-         semaphore. */
-      struct list_elem *e = list_max (&sema->waiters, priority_less, NULL);
-      list_remove (e);
-      thread_unblock (list_entry (e, struct thread, elem));
-    }
+  {
+    /* Enforces wake-up of the highest priority thread waiting for the
+       semaphore. */
+    struct list_elem *e = list_max (&sema->waiters, priority_less, NULL);
+    list_remove (e);
+    thread_unblock (list_entry (e, struct thread, elem));
+    thread_unblocked = true;
+  }
   sema->value++;
   intr_set_level (old_level);
 
   /* Yields the CPU in case the thread that has been woken up has a higher
      priority that the current running thread, including the case when called
      within an interrupt handler. */
-  if (intr_context ())
-    intr_yield_on_return ();
-  else
-    thread_yield ();
+  if (thread_unblocked)
+  {
+    if (intr_context ())
+      intr_yield_on_return ();
+    else
+      thread_yield ();
+  }
 }
 
 static void sema_test_helper (void *sema_);
@@ -347,7 +352,6 @@ lock_release (struct lock *lock)
 
   lock->holder = NULL;
   sema_up (&lock->semaphore);
-  thread_yield ();
 }
 
 /* Returns true if the current thread holds LOCK, false

From ab716de0a6ed8dcb7b2f880dd3466d14fd727c11 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Wed, 6 Nov 2024 15:46:47 +0000
Subject: [PATCH 24/25] Update process_wait to temporarily sleep for 1 second
 to allow user programs to run

---
 src/userprog/process.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/userprog/process.c b/src/userprog/process.c
index 49b9bd5..017e14b 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -17,6 +17,7 @@
 #include "threads/palloc.h"
 #include "threads/thread.h"
 #include "threads/vaddr.h"
+#include "devices/timer.h"
 
 static thread_func start_process NO_RETURN;
 static bool load (const char *cmdline, void (**eip) (void), void **esp);
@@ -88,7 +89,12 @@ start_process (void *file_name_)
 int
 process_wait (tid_t child_tid UNUSED) 
 {
-  return -1;
+  /* As a temporary wait, waiting will just put the thread to sleep for one
+     second (TIMER_FREQ = 100 ticks ~ 1 second). */
+  /* TODO: Implement process_wait () correctly. Remove the next line. */
+  timer_sleep (TIMER_FREQ);
+
+  return 0; /* TODO: Change this too */
 }
 
 /* Free the current process's resources. */

From fcb7e9e4414d320bef117be95326c81f69d35b98 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Wed, 6 Nov 2024 15:48:27 +0000
Subject: [PATCH 25/25] Update setup_stack to temporarily fake set-up for a
 stack to prevent page faults in no arg user programs

---
 src/userprog/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/userprog/process.c b/src/userprog/process.c
index 017e14b..cde4b4a 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -457,7 +457,7 @@ setup_stack (void **esp)
     {
       success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage, true);
       if (success)
-        *esp = PHYS_BASE;
+        *esp = PHYS_BASE - 12;
       else
         palloc_free_page (kpage);
     }