diff --git a/userprog/argument_parsing.h b/userprog/argument_parsing.h
index 585efe1b65621145e6316efb3b7ecfcc35c470d7..b84be707d1c4adb0e17dfeb8f92c75ce4908e8e7 100644
--- a/userprog/argument_parsing.h
+++ b/userprog/argument_parsing.h
@@ -25,9 +25,10 @@ int parse_arguments(const char* command_line, char**argv);
/*
* Given stack pointer `esp`, argument count `argc` and arguments array `argv`,
* Populates the stack pointed to by the stack pointer with the given arguments.
- * TODO: clarify what, if anything, `esp` stands for and rename it to something
- * clearer if possible.
+ * esp is the initial stack pointer from process.c,
+ * I have used stackPointer as the name as that makes sense inside,
+ * populate_stack, in process.c esp has been renamed to initial_stack_pointer
*/
-void populate_stack(void* esp, int argc, char** argv);
+void populate_stack(void** stack_pointer, int argc, char** argv);
#endif /* userprog/argument_parsing.h */
diff --git a/userprog/populate_stack.c b/userprog/populate_stack.c
index 6a7bb2e4897aa6e05b7cd050e2ebff4e41445525..d82e18fb72b85a3ac7546f23e393812534d1f83a 100644
--- a/userprog/populate_stack.c
+++ b/userprog/populate_stack.c
@@ -1,6 +1,55 @@
-#include "userprog/argument_parsing.h"
+/*
+ * populates_stack.c --implements function for populating the program stack
+ *
+ *
+ * Authored by Alex Stratford
+ */
+#include <string.h>
+#include "threads/vaddr.h"
+#include "userprog/argument_parsing.h"
-void populate_stack(void* esp, int argc, char** argv) {
- #warning "Implement me"
+ // Adds the move value to the stack pointer
+static void move_stack_pointer(void** stack_pointer, int move_value) {
+ *stack_pointer = *stack_pointer + move_value;
}
+
+void populate_stack(void** stack_pointer, int argc, char** argv) {
+ *stack_pointer = PHYS_BASE;
+ int i = argc;
+
+ uint32_t * arr[argc]; // Creates an array to hold arguments in the stack
+
+ while (--i >= 0)
+ {
+ *stack_pointer = *stack_pointer - (strlen(argv[i]) + 1) * sizeof(char);
+
+ arr[i] = (uint32_t *)*stack_pointer; // Assigns the current reference of the stack pointer to the array
+
+ memcpy(*stack_pointer, argv[i], strlen(argv[i]) + 1);
+ }
+
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
+
+ (*(int *)(*stack_pointer)) = 0;//sentinel
+ i = argc;
+
+ while (--i >= 0)
+ {
+ move_stack_pointer(stack_pointer, -4); //32bit Moves the stack pointer back 4
+
+ (*(uint32_t **)(*stack_pointer)) = arr[i];
+ }
+
+ move_stack_pointer(stack_pointer, -4);
+ move_stack_pointer(stack_pointer, 4); //Moves the stack pointer forwards 4
+ // TODO: Test if still required in later version
+
+ (*(uintptr_t **)(*stack_pointer)) = *stack_pointer;
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
+
+ *(int *)(*stack_pointer) = argc;
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
+
+ (*(int *)(*stack_pointer)) = 0;
+}
\ No newline at end of file
diff --git a/userprog/process.c b/userprog/process.c
index 5fbfb38e05f7d429a994a2e87d71221068c56531..6577694d14e487db6c346888600c65ef9e9427a0 100644
--- a/userprog/process.c
+++ b/userprog/process.c
@@ -20,8 +20,7 @@
#include "threads/vaddr.h"
static thread_func start_process NO_RETURN;
-static bool load (const char *command, void (**eip) (void), void **esp);
-
+static bool load (const char *cmdline, void (**eip) (void), void **initial_stack_pointer);
/* Starts a new thread running a user program loaded by parsing
COMMAND. The new thread may be scheduled (and may even exit)
before process_execute() returns. Returns the new process's
@@ -78,7 +77,7 @@ start_process (void *file_name_)
interrupt, implemented by intr_exit (in
threads/intr-stubs.S). Because intr_exit takes all of its
arguments on the stack in the form of a `struct intr_frame',
- we just point the stack pointer (%esp) to our stack frame
+ we just point the stack pointer (%initial_stack_pointer) to our stack frame
and jump to it. */
asm volatile ("movl %0, %%esp; jmp intr_exit" : : "g" (&if_) : "memory");
NOT_REACHED ();
@@ -211,7 +210,7 @@ struct Elf32_Phdr
#define PF_W 2 /* Writable. */
#define PF_R 4 /* Readable. */
-static bool setup_stack (void **esp, char **argv, int argc);
+static bool setup_stack(void **initial_stack_pointer, char **argv, int argc);
static bool validate_segment (const struct Elf32_Phdr *, struct file *);
static bool load_segment (struct file *file, off_t ofs, uint8_t *upage,
uint32_t read_bytes, uint32_t zero_bytes,
@@ -219,10 +218,10 @@ static bool load_segment (struct file *file, off_t ofs, uint8_t *upage,
/* Loads an ELF executable from COMMAND into the current thread.
Stores the executable's entry point into *EIP
- and its initial stack pointer into *ESP.
+ and its initial stack pointer into *initial_stack_pointer.
Returns true if successful, false otherwise. */
bool
-load (const char *command, void (**eip) (void), void **esp)
+load (const char *cmdline, void (**eip) (void), void **initial_stack_pointer)
{
struct thread *t = thread_current ();
struct Elf32_Ehdr ehdr;
@@ -235,7 +234,7 @@ load (const char *command, void (**eip) (void), void **esp)
char* argv[USERPROG_ARGV_COUNT];
// copy the command string so we have a separate copy to manipulate
char command_copy[USERPROG_RAW_ARGV_LENGTH];
- strlcpy(command_copy, command, USERPROG_RAW_ARGV_LENGTH);
+ strlcpy(command_copy, cmdline, USERPROG_RAW_ARGV_LENGTH);
int argc = parse_arguments(command_copy, argv);
char* file_name = argv[0]; // file name is always argument 0
@@ -250,12 +249,12 @@ load (const char *command, void (**eip) (void), void **esp)
if (file == NULL)
{
- printf ("load: %s: open failed\n", file_name);
+ printf ("load: %s: open failed\n", cmdline);
goto done;
}
/* Read and verify executable header. */
- if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr
+ if (file_read(file, &ehdr, sizeof ehdr) != sizeof ehdr
|| memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7)
|| ehdr.e_type != 2
|| ehdr.e_machine != 3
@@ -263,7 +262,7 @@ load (const char *command, void (**eip) (void), void **esp)
|| ehdr.e_phentsize != sizeof (struct Elf32_Phdr)
|| ehdr.e_phnum > 1024)
{
- printf ("load: %s: error loading executable\n", file_name);
+ printf ("load: %s: error loading executable\n", cmdline);
goto done;
}
@@ -327,7 +326,7 @@ load (const char *command, void (**eip) (void), void **esp)
}
/* Set up stack. */
- if (!setup_stack (esp, argv, argc))
+ if (!setup_stack (initial_stack_pointer, argv, argc))
goto done;
/* Start address. */
@@ -452,7 +451,7 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
/* Create a minimal stack by mapping a zeroed page at the top of
user virtual memory. */
static bool
-setup_stack (void **esp, char **argv, int argc)
+setup_stack (void **initial_stack_pointer, char **argv, int argc)
{
uint8_t *kpage;
bool success = false;
@@ -462,8 +461,8 @@ setup_stack (void **esp, char **argv, int argc)
{
success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage, true);
if (success) {
- *esp = PHYS_BASE - 12;
- populate_stack(esp, argc, argv);
+ *initial_stack_pointer = PHYS_BASE - 12;
+ populate_stack(initial_stack_pointer, argc, argv);
} else
palloc_free_page (kpage);
}
diff --git a/utils/pintos b/utils/pintos
index 16a725a9ef4dd44351f9b82e911eca1841cd50b1..53942f2427d78512a635eef98ffef3adb9293f56 100755
--- a/utils/pintos
+++ b/utils/pintos
@@ -929,15 +929,18 @@ sub exec_setitimer {
exit (1);
}
-sub SIGVTALRM {
- use Config;
- my $i = 0;
- foreach my $name (split(' ', $Config{sig_name})) {
- return $i if $name eq 'VTALRM';
- $i++;
- }
- return 0;
-}
+# This subroutine has been commented out because otherwise if it is not then
+# Pintos will refuse to run at all once the code for putting arguments into
+# the stack is added
+#sub SIGVTALRM {
+# use Config;
+# my $i = 0;
+# foreach my $name (split(' ', $Config{sig_name})) {
+# return $i if $name eq 'VTALRM';
+# $i++;
+# }
+# return 0;
+#}
# find_in_path ($program)
#