diff --git a/userprog/argument_parsing.h b/userprog/argument_parsing.h
index 37b47e8003c0e7bdbc9cd3cabcb1eca421e8aa82..b84be707d1c4adb0e17dfeb8f92c75ce4908e8e7 100644
--- a/userprog/argument_parsing.h
+++ b/userprog/argument_parsing.h
@@ -1,14 +1,26 @@
+/*
+ * argument_parsing.h --prototypes functions required for parsing arguments from
+ * command line and placing these into the program stack structure.
+ *
+ * Authored by Joshua Saxby
+ */
#ifndef USERPROG_ARGUMENT_PARSING_H
#define USERPROG_ARGUMENT_PARSING_H
+
+// some macros for argument length and count limits
+// TODO: decide how many arguments we want --is 255 the standard number?
+#define USERPROG_ARGV_COUNT 255
+// TODO: clarify what a sensible value for this is
+#define USERPROG_RAW_ARGV_LENGTH 255
+
/*
* Given a string containing the command invoking the program `command_line`
- * and a pointer to an array of C strings (pointer to `char* argv[]`), parse
- * `command_line` into individual arguments, populate `argv` with these and
- * return the number of arguments that were parsed (this is the value that can
- * be used for `argc`).
+ * and an array of C strings (pointer to `char* argv[]`), parse `command_line`
+ * into individual arguments, populate `argv` with these and return the number
+ * of arguments that were parsed (this is the value that can be used for `argc`).
*/
-int parse_arguments(const char* command_line, char***argv);
+int parse_arguments(const char* command_line, char**argv);
/*
* Given stack pointer `esp`, argument count `argc` and arguments array `argv`,
diff --git a/userprog/parse_arguments.c b/userprog/parse_arguments.c
index aeaefd0778156808a54f8c2b1da7b1197886efbc..9de6f294fa5d77fc3319b6a36cb7c52458ed1241 100644
--- a/userprog/parse_arguments.c
+++ b/userprog/parse_arguments.c
@@ -1,6 +1,29 @@
+/*
+ * parse_arguments.c --implements function for parsing a command-line string
+ * into the program arguments contained within it.
+ *
+ * Authored by Joshua Saxby
+ */
+#include <stddef.h>
+#include <string.h>
+
#include "userprog/argument_parsing.h"
-int parse_arguments(const char* command_line, char***argv) {
- #warning "Implement me"
+int parse_arguments(const char* command_line, char**argv) {
+ int argc = 0;
+ // the state pointer required by strtok_r() for use between calls
+ char* state_pointer;
+ // first call to strtok_r() is the only one where string to parse is passed
+ argv[0] = strtok_r(command_line, " ", &state_pointer);
+ argc++;
+ // now, parse token-by-token for any additional arguments
+ char* token = strtok_r(NULL, " ", &state_pointer);
+ // continue while still tokens to read and maximum arg count is not reached
+ while (token != NULL && argc < USERPROG_ARGV_COUNT) {
+ argv[argc] = token;
+ argc++;
+ token = strtok_r(NULL, " ", &state_pointer);
+ }
+ return argc;
}
diff --git a/userprog/process.c b/userprog/process.c
index e5b66aa9108910c254ec627497800cadc2c3b0bb..98ff0aaff1c93c0851eefa08c7a947534314f5d0 100644
--- a/userprog/process.c
+++ b/userprog/process.c
@@ -5,6 +5,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include "userprog/argument_parsing.h"
#include "userprog/gdt.h"
#include "userprog/pagedir.h"
#include "userprog/tss.h"
@@ -20,7 +21,6 @@
static thread_func start_process NO_RETURN;
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
@@ -29,24 +29,22 @@ tid_t
process_execute (const char *command)
{
char *command_copy;
- tid_t tid;
-
/* Make a copy of COMMAND.
Otherwise there's a race between the caller and load(). */
command_copy = palloc_get_page (0);
if (command_copy == NULL)
return TID_ERROR;
strlcpy (command_copy, command, PGSIZE);
+ // we need to extract out the filename from the command string
+ char* file_name;
+ char* save_ptr; // this is the save pointer expected by strtok_r()
+ // file name is the first part of the command-line (space-delimited)
+ file_name = strtok_r(command, " ", &save_ptr);
+ tid_t tid;
+
/* Create a new thread to execute COMMAND. */
- /*
- * FIXME: right now, COMMAND is assumed to be just the filename on its own
- *
- * If this is not the case (if the user passed a program name with arguments),
- * then loading will fail.
- * NOTE: remove this comment block when argument parsing is implemented.
- */
- tid = thread_create (command, PRI_DEFAULT, start_process, command_copy);
+ tid = thread_create (file_name, PRI_DEFAULT, start_process, command_copy);
if (tid == TID_ERROR)
palloc_free_page (command_copy);
@@ -218,7 +216,7 @@ static bool load_segment (struct file *file, off_t ofs, uint8_t *upage,
uint32_t read_bytes, uint32_t zero_bytes,
bool writable);
-/* Loads an ELF executable from FILE_NAME into the current thread.
+/* Loads an ELF executable from COMMAND into the current thread.
Stores the executable's entry point into *EIP
and its initial stack pointer into *initial_stack_pointer.
Returns true if successful, false otherwise. */
@@ -232,6 +230,14 @@ load (const char *cmdline, void (**eip) (void), void **initial_stack_pointer)
bool success = false;
int i;
+ // extract arguments (including file name)
+ 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, cmdline, USERPROG_RAW_ARGV_LENGTH);
+ int argc = parse_arguments(command_copy, argv);
+ char* file_name = argv[0]; // file name is always argument 0
+
/* Allocate and activate page directory. */
t->pagedir = pagedir_create ();
if (t->pagedir == NULL)
@@ -239,7 +245,7 @@ load (const char *cmdline, void (**eip) (void), void **initial_stack_pointer)
process_activate ();
/* Open executable file. */
- file = filesys_open (cmdline);
+ file = filesys_open (file_name);
if (file == NULL)
{
@@ -320,7 +326,7 @@ load (const char *cmdline, void (**eip) (void), void **initial_stack_pointer)
}
/* Set up stack. */
- if (!setup_stack (initial_stack_pointer))
+ if (!setup_stack (initial_stack_pointer, argv, argc))
goto done;
/* Start address. */
@@ -456,6 +462,7 @@ setup_stack (void **initial_stack_pointer, char **argv, int argc)
success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage, true);
if (success) {
*initial_stack_pointer = PHYS_BASE - 12;
+ populate_stack(initial_stack_pointer, argc, argv);
} else
palloc_free_page (kpage);
}