diff --git a/src/userprog/process.c b/src/userprog/process.c
index 890165a8d922983315e45ae0a1c500acfa327f27..45c2fd527cbfb828b5b33a21b51ea4998a797975 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -1,571 +1,3 @@
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-Update src/userprog/process.c
-sa2-alarjani authored 1 day ago
-a984983a
-process.c
-15.67 KiB
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#include "userprog/process.h"
#include <debug.h>
#include <inttypes.h>
@@ -585,8 +17,10 @@ process.c
#include "threads/palloc.h"
#include "threads/thread.h"
#include "threads/vaddr.h"
+
static thread_func start_process NO_RETURN;
static bool load (const char *cmdline, void (**eip) (void), void **esp);
+
/* 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
@@ -596,22 +30,27 @@ process_execute (const char *file_name)
{
char *fn_copy, *filename_, *args;
tid_t tid;
+
/* Make a copy of FILE_NAME.
Otherwise there's a race between the caller and load(). */
fn_copy = palloc_get_page (0);
if (fn_copy == NULL)
return TID_ERROR;
strlcpy (fn_copy, file_name, PGSIZE);
+
int len = strlen(file_name) + 1;
char file_copy[len];
strlcpy(file_copy, file_name, len);
filename_ = strtok_r(file_copy, " ", &args);
+
/* Create a new thread to execute FILE_NAME. */
tid = thread_create (filename_, PRI_DEFAULT, start_process, fn_copy);
+
if (tid == TID_ERROR)
palloc_free_page (fn_copy);
return tid;
}
+
/* A thread function that loads a user process and starts it
running. */
static void
@@ -620,17 +59,20 @@ start_process (void *file_name_)
char *file_name = file_name_;
struct intr_frame if_;
bool success;
+
/* Initialize interrupt frame and load executable. */
memset (&if_, 0, sizeof if_);
if_.gs = if_.fs = if_.es = if_.ds = if_.ss = SEL_UDSEG;
if_.cs = SEL_UCSEG;
if_.eflags = FLAG_IF | FLAG_MBS;
+
success = load (file_name, &if_.eip, &if_.esp);
/* If load failed, quit. */
palloc_free_page (file_name);
if (!success)
thread_exit ();
+
/* Start the user process by simulating a return from an
interrupt, implemented by intr_exit (in
threads/intr-stubs.S). Because intr_exit takes all of its
@@ -640,12 +82,14 @@ start_process (void *file_name_)
asm volatile ("movl %0, %%esp; jmp intr_exit" : : "g" (&if_) : "memory");
NOT_REACHED ();
}
+
/* 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. */
int
@@ -656,13 +100,16 @@ process_wait (tid_t child_tid UNUSED)
return -1;
}
+
/* Free the current process's resources. */
void
process_exit (void)
{
struct thread *cur = thread_current ();
uint32_t *pd;
+
printf("%s: exit_code(%d)\n",cur->name,cur->exit_code);
+
/* Destroy the current process's page directory and switch back
to the kernel-only page directory. */
pd = cur->pagedir;
@@ -680,6 +127,7 @@ process_exit (void)
pagedir_destroy (pd);
}
}
+
/* Sets up the CPU for running user code in the current
thread.
This function is called on every context switch. */
@@ -687,8 +135,10 @@ void
process_activate (void)
{
struct thread *t = thread_current ();
+
/* Activate thread's page tables. */
pagedir_activate (t->pagedir);
+
/* Set thread's kernel stack for use in processing
interrupts. */
tss_update ();
@@ -696,14 +146,17 @@ process_activate (void)
/* We load ELF binaries. The following definitions are taken
from the ELF specification, [ELF1], more-or-less verbatim. */
+
/* ELF types. See [ELF1] 1-2. */
typedef uint32_t Elf32_Word, Elf32_Addr, Elf32_Off;
typedef uint16_t Elf32_Half;
+
/* For use with ELF types in printf(). */
#define PE32Wx PRIx32 /* Print Elf32_Word in hexadecimal. */
#define PE32Ax PRIx32 /* Print Elf32_Addr in hexadecimal. */
#define PE32Ox PRIx32 /* Print Elf32_Off in hexadecimal. */
#define PE32Hx PRIx16 /* Print Elf32_Half in hexadecimal. */
+
/* Executable header. See [ELF1] 1-4 to 1-8.
This appears at the very beginning of an ELF binary. */
struct Elf32_Ehdr
@@ -723,6 +176,7 @@ struct Elf32_Ehdr
Elf32_Half e_shnum;
Elf32_Half e_shstrndx;
};
+
/* Program header. See [ELF1] 2-2 to 2-4.
There are e_phnum of these, starting at file offset e_phoff
(see [ELF1] 1-6). */
@@ -737,6 +191,7 @@ struct Elf32_Phdr
Elf32_Word p_flags;
Elf32_Word p_align;
};
+
/* Values for p_type. See [ELF1] 2-3. */
#define PT_NULL 0 /* Ignore. */
#define PT_LOAD 1 /* Loadable segment. */
@@ -746,10 +201,12 @@ struct Elf32_Phdr
#define PT_SHLIB 5 /* Reserved. */
#define PT_PHDR 6 /* Program header table. */
#define PT_STACK 0x6474e551 /* Stack segment. */
+
/* Flags for p_flags. See [ELF3] 2-3 and 2-4. */
#define PF_X 1 /* Executable. */
#define PF_W 2 /* Writable. */
#define PF_R 4 /* Readable. */
+
static bool setup_stack (void **esp, char *filename, char *argu);
static bool validate_segment (const struct Elf32_Phdr *, struct file *);
static bool load_segment (struct file *file, off_t ofs, uint8_t *upage,
@@ -774,18 +231,22 @@ load (const char *file_name, void (**eip) (void), void **esp)
strlcpy(file_copy, file_name, len);
char *args, *file_name_;
file_name_ = strtok_r(file_copy, " ", &args);
+
/* Allocate and activate page directory. */
t->pagedir = pagedir_create ();
if (t->pagedir == NULL)
goto done;
process_activate ();
+
/* Open executable file. */
file = filesys_open (file_name_);
+
if (file == NULL)
{
printf ("load: %s: open failed\n", file_name_);
goto done;
}
+
/* Read and verify executable header. */
if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr
|| memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7)
@@ -798,14 +259,17 @@ load (const char *file_name, void (**eip) (void), void **esp)
printf ("load: %s: error loading executable\n", file_name_);
goto done;
}
+
/* Read program headers. */
file_ofs = ehdr.e_phoff;
for (i = 0; i < ehdr.e_phnum; i++)
{
struct Elf32_Phdr phdr;
+
if (file_ofs < 0 || file_ofs > file_length (file))
goto done;
file_seek (file, file_ofs);
+
if (file_read (file, &phdr, sizeof phdr) != sizeof phdr)
goto done;
file_ofs += sizeof phdr;
@@ -854,12 +318,16 @@ load (const char *file_name, void (**eip) (void), void **esp)
break;
}
}
+
/* Set up stack. */
if (!setup_stack (esp, file_name_, args))
goto done;
+
/* Start address. */
*eip = (void (*) (void)) ehdr.e_entry;
+
success = true;
+
done:
/* We arrive here whether the load is successful or not. */
file_close (file);
@@ -867,7 +335,9 @@ load (const char *file_name, void (**eip) (void), void **esp)
}
/* load() helpers. */
+
static bool install_page (void *upage, void *kpage, bool writable);
+
/* Checks whether PHDR describes a valid, loadable segment in
FILE and returns true if so, false otherwise. */
static bool
@@ -876,12 +346,15 @@ validate_segment (const struct Elf32_Phdr *phdr, struct file *file)
/* p_offset and p_vaddr must have the same page offset. */
if ((phdr->p_offset & PGMASK) != (phdr->p_vaddr & PGMASK))
return false;
+
/* p_offset must point within FILE. */
if (phdr->p_offset > (Elf32_Off) file_length (file))
return false;
+
/* p_memsz must be at least as big as p_filesz. */
if (phdr->p_memsz < phdr->p_filesz)
return false;
+
/* The segment must not be empty. */
if (phdr->p_memsz == 0)
return false;
@@ -892,10 +365,12 @@ validate_segment (const struct Elf32_Phdr *phdr, struct file *file)
return false;
if (!is_user_vaddr ((void *) (phdr->p_vaddr + phdr->p_memsz)))
return false;
+
/* The region cannot "wrap around" across the kernel virtual
address space. */
if (phdr->p_vaddr + phdr->p_memsz < phdr->p_vaddr)
return false;
+
/* Disallow mapping page 0.
Not only is it a bad idea to map page 0, but if we allowed
it then user code that passed a null pointer to system calls
@@ -903,17 +378,23 @@ validate_segment (const struct Elf32_Phdr *phdr, struct file *file)
assertions in memcpy(), etc. */
if (phdr->p_vaddr < PGSIZE)
return false;
+
/* It's okay. */
return true;
}
+
/* 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. */
static bool
@@ -923,6 +404,7 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
ASSERT ((read_bytes + zero_bytes) % PGSIZE == 0);
ASSERT (pg_ofs (upage) == 0);
ASSERT (ofs % PGSIZE == 0);
+
file_seek (file, ofs);
while (read_bytes > 0 || zero_bytes > 0)
{
@@ -931,10 +413,12 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
and zero the final PAGE_ZERO_BYTES bytes. */
size_t page_read_bytes = read_bytes < PGSIZE ? read_bytes : PGSIZE;
size_t page_zero_bytes = PGSIZE - page_read_bytes;
+
/* Get a page of memory. */
uint8_t *kpage = palloc_get_page (PAL_USER);
if (kpage == NULL)
return false;
+
/* Load this page. */
if (file_read (file, kpage, page_read_bytes) != (int) page_read_bytes)
{
@@ -942,12 +426,14 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
return false;
}
memset (kpage + page_read_bytes, 0, page_zero_bytes);
+
/* Add the page to the process's address space. */
if (!install_page (upage, kpage, writable))
{
palloc_free_page (kpage);
return false;
}
+
/* Advance. */
read_bytes -= page_read_bytes;
zero_bytes -= page_zero_bytes;
@@ -955,6 +441,7 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
}
return true;
}
+
/* Create a minimal stack by mapping a zeroed page at the top of
user virtual memory. */
static bool
@@ -962,6 +449,7 @@ setup_stack (void **esp, char *filename, char *argu)
{
uint8_t *kpage;
bool success = false;
+
kpage = palloc_get_page (PAL_USER | PAL_ZERO);
if (kpage != NULL)
{
@@ -977,6 +465,7 @@ setup_stack (void **esp, char *filename, char *argu)
}
return success;
}
+
/* 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;
@@ -990,11 +479,13 @@ static bool
install_page (void *upage, void *kpage, bool writable)
{
struct thread *t = thread_current ();
+
/* Verify that there's not already a page at that virtual
address, then map our page there. */
return (pagedir_get_page (t->pagedir, upage) == NULL
&& pagedir_set_page (t->pagedir, upage, kpage, writable));
}
+
/*Helper function push name of file and arguments on esp stack*/
void
handle_argsinstack(void **esp, char *file_name, char *args)
@@ -1018,6 +509,7 @@ handle_argsinstack(void **esp, char *file_name, char *args)
memcpy(*esp,argu_arr[i],arg_len);
argus[arg_c - i + 1] = *esp;
}
+
//push the name of file on esp stack
int size = strlen(file_name) + 1;
*esp -= size;
@@ -1025,6 +517,7 @@ handle_argsinstack(void **esp, char *file_name, char *args)
argus[0] = *esp;
argus[arg_c + 1] = NULL;
+
//Add Padding to align the esp stack
int pad = 4 * ((t_arg_s) / 4);
*esp -= pad;
@@ -1035,4 +528,5 @@ handle_argsinstack(void **esp, char *file_name, char *args)
memcpy(*esp,argus,4*(arg_c + 1));
}
+
//--------------------------------------------------------------------