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Refactor process_execute to remove use of 'goto'

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Themis Demetriades
2024-11-14 14:42:26 +00:00
parent 1a2ff35231
commit 8821851459
1 changed files with 12 additions and 18 deletions
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30
src/userprog/process.c
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@@ -67,9 +67,6 @@ process_execute (const char *cmd)
struct process_start_data data; struct process_start_data data;
sema_init (&data.loaded, 0);
data.success = false;
/* Make a copy of command. /* Make a copy of command.
Otherwise there's a race between the caller and load(). */ Otherwise there's a race between the caller and load(). */
cmd_copy = palloc_get_page (0); cmd_copy = palloc_get_page (0);
@@ -99,6 +96,8 @@ process_execute (const char *cmd)
arguments. For details of arguments, see 'start_process'. */ arguments. For details of arguments, see 'start_process'. */
data.cmd = cmd_copy; data.cmd = cmd_copy;
strlcpy (data.file_name, file_name, FNAME_MAX_LEN + 1); strlcpy (data.file_name, file_name, FNAME_MAX_LEN + 1);
sema_init (&data.loaded, 0);
data.success = false;
tid = thread_create (file_name, PRI_DEFAULT, start_process, &data); tid = thread_create (file_name, PRI_DEFAULT, start_process, &data);
if (tid == TID_ERROR) if (tid == TID_ERROR)
@@ -126,7 +125,6 @@ static void
start_process (void *proc_start_data) start_process (void *proc_start_data)
{ {
struct intr_frame if_; struct intr_frame if_;
bool success;
struct process_start_data *data = proc_start_data; struct process_start_data *data = proc_start_data;
@@ -143,34 +141,36 @@ start_process (void *proc_start_data)
if (exec_file == NULL) if (exec_file == NULL)
{ {
lock_release (&filesys_lock); lock_release (&filesys_lock);
goto fail; sema_up (&data->loaded);
thread_exit ();
} }
thread_current ()->exec_file = exec_file; thread_current ()->exec_file = exec_file;
file_deny_write (exec_file); file_deny_write (exec_file);
lock_release (&filesys_lock); lock_release (&filesys_lock);
success = load (data->file_name, &if_.eip, &if_.esp); data->success = load (data->file_name, &if_.eip, &if_.esp);
/* If load failed, quit. */ /* If load failed, quit. */
if (!success) if (!data->success)
{ {
palloc_free_page (data->cmd); palloc_free_page (data->cmd);
goto fail; sema_up (&data->loaded);
thread_exit ();
} }
/* Initialize user process stack and free page used to store the /* Initialize user process stack and free page used to store the
command that executed the process. */ command that executed the process. */
success = process_init_stack (data->cmd_saveptr, &if_.esp, data->file_name); data->success = process_init_stack (data->cmd_saveptr, &if_.esp, data->file_name);
bool success = data->success;
palloc_free_page (data->cmd); palloc_free_page (data->cmd);
sema_up (&data->loaded);
/* If stack initialization failed, free resources and quit. */ /* If stack initialization failed, free resources and quit. */
if (!success) if (!success)
{ {
goto fail; thread_exit ();
} }
data->success = true;
sema_up (&data->loaded);
/* Start the user process by simulating a return from an /* Start the user process by simulating a return from an
interrupt, implemented by intr_exit (in interrupt, implemented by intr_exit (in
threads/intr-stubs.S). Because intr_exit takes all of its threads/intr-stubs.S). Because intr_exit takes all of its
@@ -179,12 +179,6 @@ start_process (void *proc_start_data)
and jump to it. */ and jump to it. */
asm volatile ("movl %0, %%esp; jmp intr_exit" : : "g" (&if_) : "memory"); asm volatile ("movl %0, %%esp; jmp intr_exit" : : "g" (&if_) : "memory");
NOT_REACHED (); NOT_REACHED ();
/* If starting the process failed, exit. */
fail:
data->success = false;
sema_up (&data->loaded);
thread_exit ();
} }
/* Helper function that initializes the stack of a newly created /* Helper function that initializes the stack of a newly created