#include "userprog/process.h"
#include <debug.h>
#include <inttypes.h>
#include <round.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "userprog/gdt.h"
#include "userprog/pagedir.h"
#include "userprog/tss.h"
#include "filesys/directory.h"
#include "filesys/file.h"
#include "filesys/filesys.h"
#include "threads/flags.h"
#include "threads/init.h"
#include "threads/interrupt.h"
#include "threads/palloc.h"
#include "threads/thread.h"
#include "threads/vaddr.h"

Include dependency graph for process.c:

Data Structures
struct	Elf32_Ehdr
	Executable header. More...

struct	Elf32_Phdr
	Program header. More...

Macros
#define	PE32Wx PRIx32
	For use with ELF types in printf(). More...

#define	PE32Ax PRIx32
	Print Elf32_Addr in hexadecimal. More...

#define	PE32Ox PRIx32
	Print Elf32_Off in hexadecimal. More...

#define	PE32Hx PRIx16
	Print Elf32_Half in hexadecimal. More...

#define	PT_NULL 0
	Values for p_type. More...

#define	PT_LOAD 1
	Loadable segment. More...

#define	PT_DYNAMIC 2
	Dynamic linking info. More...

#define	PT_INTERP 3
	Name of dynamic loader. More...

#define	PT_NOTE 4
	Auxiliary info. More...

#define	PT_SHLIB 5
	Reserved. More...

#define	PT_PHDR 6
	Program header table. More...

#define	PT_STACK 0x6474e551
	Stack segment. More...

#define	PF_X 1
	Flags for p_flags. More...

#define	PF_W 2
	Writable. More...

#define	PF_R 4
	Readable. More...

Typedefs
typedef uint32_t	Elf32_Word
	We load ELF binaries. More...

typedef uint32_t	Elf32_Addr

typedef uint32_t	Elf32_Off

typedef uint16_t	Elf32_Half

Functions
static bool	load (const char file_name, void(eip)(void), void *esp)
	Loads an ELF executable from FILE_NAME into the current thread. More...

tid_t	process_execute (const char *file_name)
	Starts a new thread running a user program loaded from FILENAME. More...

static void	start_process (void *file_name_)
	A thread function that loads a user process and starts it running. More...

int	process_wait (tid_t child_tid UNUSED)
	Waits for thread TID to die and returns its exit status. More...

void	process_exit (void)
	Free the current process's resources. More...

void	process_activate (void)
	Sets up the CPU for running user code in the current thread. More...

static bool	setup_stack (void **esp)
	Create a minimal stack by mapping a zeroed page at the top of user virtual memory. More...

static bool	validate_segment (const struct Elf32_Phdr phdr, struct file file)
	Checks whether PHDR describes a valid, loadable segment in FILE and returns true if so, false otherwise. More...

static bool	load_segment (struct file file, off_t ofs, uint8_t upage, uint32_t read_bytes, uint32_t zero_bytes, bool writable)
	Loads a segment starting at offset OFS in FILE at address UPAGE. More...

static bool	install_page (void upage, void kpage, bool writable)
	load() helpers. More...

Variables
static thread_func start_process	NO_RETURN

Macro Definition Documentation

◆ PE32Ax

#define PE32Ax PRIx32

Print Elf32_Addr in hexadecimal.

Definition at line 144 of file process.c.

◆ PE32Hx

#define PE32Hx PRIx16

Print Elf32_Half in hexadecimal.

Definition at line 146 of file process.c.

◆ PE32Ox

#define PE32Ox PRIx32

Print Elf32_Off in hexadecimal.

Definition at line 145 of file process.c.

◆ PE32Wx

#define PE32Wx PRIx32

For use with ELF types in printf().

Print Elf32_Word in hexadecimal.

Definition at line 143 of file process.c.

◆ PF_R

#define PF_R 4

Readable.

Definition at line 196 of file process.c.

◆ PF_W

#define PF_W 2

Writable.

Definition at line 195 of file process.c.

◆ PF_X

#define PF_X 1

Flags for p_flags.

See [ELF3] 2-3 and 2-4. Executable.

Definition at line 194 of file process.c.

◆ PT_DYNAMIC

#define PT_DYNAMIC 2

Dynamic linking info.

Definition at line 186 of file process.c.

◆ PT_INTERP

#define PT_INTERP 3

Name of dynamic loader.

Definition at line 187 of file process.c.

◆ PT_LOAD

#define PT_LOAD 1

Loadable segment.

Definition at line 185 of file process.c.

◆ PT_NOTE

#define PT_NOTE 4

Auxiliary info.

Definition at line 188 of file process.c.

◆ PT_NULL

#define PT_NULL 0

Values for p_type.

See [ELF1] 2-3. Ignore.

Definition at line 184 of file process.c.

◆ PT_PHDR

#define PT_PHDR 6

Program header table.

Definition at line 190 of file process.c.

◆ PT_SHLIB

#define PT_SHLIB 5

Reserved.

Definition at line 189 of file process.c.

◆ PT_STACK

#define PT_STACK 0x6474e551

Stack segment.

Definition at line 191 of file process.c.

Typedef Documentation

◆ Elf32_Addr

typedef uint32_t Elf32_Addr

Definition at line 139 of file process.c.

◆ Elf32_Half

typedef uint16_t Elf32_Half

Definition at line 140 of file process.c.

◆ Elf32_Off

typedef uint32_t Elf32_Off

Definition at line 139 of file process.c.

◆ Elf32_Word

typedef uint32_t Elf32_Word

We load ELF binaries.

The following definitions are taken from the ELF specification, [ELF1], more-or-less verbatim.
ELF types. See [ELF1] 1-2.

Definition at line 139 of file process.c.

Function Documentation

◆ install_page()

static bool install_page	(	void *	upage,
		void *	kpage,
		bool	writable
	)

static

load() helpers.

Adds a mapping from user virtual address UPAGE to kernel virtual address KPAGE to the page table.

If WRITABLE is true, the user process may modify the page; otherwise, it is read-only. UPAGE must not already be mapped. KPAGE should probably be a page obtained from the user pool with palloc_get_page(). Returns true on success, false if UPAGE is already mapped or if memory allocation fails.

Definition at line 457 of file process.c.

References NULL, pagedir_get_page(), pagedir_set_page(), and thread_current().

Referenced by load_segment(), and setup_stack().

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◆ load()

bool load	(	const char *	file_name,
		void(**)(void)	eip,
		void **	esp
	)

static

Loads an ELF executable from FILE_NAME into the current thread.

Stores the executable's entry point into *EIP and its initial stack pointer into *ESP. Returns true if successful, false otherwise.

Definition at line 209 of file process.c.

References Elf32_Ehdr::e_entry, Elf32_Ehdr::e_ident, Elf32_Ehdr::e_machine, Elf32_Ehdr::e_phentsize, Elf32_Ehdr::e_phnum, Elf32_Ehdr::e_phoff, Elf32_Ehdr::e_type, Elf32_Ehdr::e_version, file_close(), file_length(), file_name, file_read(), file_seek(), filesys_open(), load_segment(), memcmp(), NULL, Elf32_Phdr::p_filesz, Elf32_Phdr::p_flags, Elf32_Phdr::p_memsz, Elf32_Phdr::p_offset, Elf32_Phdr::p_type, Elf32_Phdr::p_vaddr, pagedir_create(), PF_W, PGMASK, PGSIZE, printf(), process_activate(), PT_DYNAMIC, PT_INTERP, PT_LOAD, PT_NOTE, PT_NULL, PT_PHDR, PT_SHLIB, PT_STACK, ROUND_UP, setup_stack(), thread_current(), and validate_segment().

Referenced by start_process().

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◆ load_segment()

static bool load_segment	(	struct file *	file,
		off_t	ofs,
		uint8_t *	upage,
		uint32_t	read_bytes,
		uint32_t	zero_bytes,
		bool	writable
	)

static

Loads a segment starting at offset OFS in FILE at address UPAGE.

In total, READ_BYTES + ZERO_BYTES bytes of virtual memory are initialized, as follows:

 - READ_BYTES bytes at UPAGE must be read from FILE
   starting at offset OFS.

 - ZERO_BYTES bytes at UPAGE + READ_BYTES must be zeroed.

The pages initialized by this function must be writable by the user process if WRITABLE is true, read-only otherwise.

Return true if successful, false if a memory allocation error or disk read error occurs.

Definition at line 383 of file process.c.

References ASSERT, file_read(), file_seek(), install_page(), memset(), NULL, PAL_USER, palloc_free_page(), palloc_get_page(), pg_ofs(), and PGSIZE.

Referenced by load().

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◆ process_activate()

void process_activate ( void )

Sets up the CPU for running user code in the current thread.

userprog/process.h

This function is called on every context switch.

Definition at line 123 of file process.c.

References pagedir_activate(), thread_current(), and tss_update().

Referenced by load(), and thread_schedule_tail().

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◆ process_execute()

tid_t process_execute ( const char * file_name )

Starts a new thread running a user program loaded from FILENAME.

The new thread may be scheduled (and may even exit) before process_execute() returns. Returns the new process's thread id, or TID_ERROR if the thread cannot be created.

Definition at line 29 of file process.c.

References file_name, NULL, palloc_free_page(), palloc_get_page(), PGSIZE, PRI_DEFAULT, start_process(), strlcpy(), thread_create(), and TID_ERROR.

Referenced by run_task().

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◆ process_exit()

void process_exit ( void )

Free the current process's resources.

Definition at line 96 of file process.c.

References NULL, pagedir_activate(), pagedir_destroy(), and thread_current().

Referenced by thread_exit().

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◆ process_wait()

int process_wait ( tid_t child_tid UNUSED )

Waits for thread TID to die and returns its exit status.

If it was terminated by the kernel (i.e. killed due to an exception), returns -1. If TID is invalid or if it was not a child of the calling process, or if process_wait() has already been successfully called for the given TID, returns -1 immediately, without waiting.

This function will be implemented in problem 2-2. For now, it does nothing.

Definition at line 89 of file process.c.

Referenced by run_task().

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◆ setup_stack()

static bool setup_stack ( void ** esp )

static

Create a minimal stack by mapping a zeroed page at the top of user virtual memory.

Definition at line 430 of file process.c.

References install_page(), NULL, PAL_USER, PAL_ZERO, palloc_free_page(), palloc_get_page(), PGSIZE, and PHYS_BASE.

Referenced by load().

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◆ start_process()

static void start_process ( void * file_name_ )

static

A thread function that loads a user process and starts it running.

Definition at line 51 of file process.c.

References intr_frame::cs, intr_frame::ds, intr_frame::eflags, intr_frame::eip, intr_frame::es, intr_frame::esp, file_name, FLAG_IF, FLAG_MBS, intr_frame::fs, intr_frame::gs, load(), memset(), NOT_REACHED, palloc_free_page(), SEL_UCSEG, SEL_UDSEG, intr_frame::ss, and thread_exit().

Referenced by process_execute().

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◆ validate_segment()

static bool validate_segment	(	const struct Elf32_Phdr *	phdr,
		struct file *	file
	)

static

Checks whether PHDR describes a valid, loadable segment in FILE and returns true if so, false otherwise.

Definition at line 326 of file process.c.

References file_length(), is_user_vaddr(), Elf32_Phdr::p_filesz, Elf32_Phdr::p_memsz, Elf32_Phdr::p_offset, Elf32_Phdr::p_vaddr, PGMASK, and PGSIZE.

Referenced by load().

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Variable Documentation

◆ NO_RETURN

thread_func start_process NO_RETURN

static

Definition at line 21 of file process.c.

Data Structures

Macros

Typedefs

Functions

Variables

Macro Definition Documentation

◆ PE32Ax

◆ PE32Hx

◆ PE32Ox

◆ PE32Wx

◆ PF_R

◆ PF_W

◆ PF_X

◆ PT_DYNAMIC

◆ PT_INTERP

◆ PT_LOAD

◆ PT_NOTE

◆ PT_NULL

◆ PT_PHDR

◆ PT_SHLIB

◆ PT_STACK

Typedef Documentation

◆ Elf32_Addr

◆ Elf32_Half

◆ Elf32_Off

◆ Elf32_Word

Function Documentation

◆ install_page()

◆ load()

◆ load_segment()

◆ process_activate()

◆ process_execute()

◆ process_exit()

◆ process_wait()

◆ setup_stack()

◆ start_process()

◆ validate_segment()

Variable Documentation

◆ NO_RETURN