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Merge branch 'stack-init-memfix' into 'master'

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Fix memory leak in start_process

See merge request lab2425_autumn/pintos_22!42
This commit is contained in:
Demetriades, Themis
2024-11-14 21:06:20 +00:00
parent bbe41e178d 5e2e7199f2
commit 9b82947beb
1 changed files with 4 additions and 12 deletions
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16
src/userprog/process.c
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@@ -40,8 +40,6 @@ struct arg_elem
that executes process_start for the purpose of starting a user process. */ that executes process_start for the purpose of starting a user process. */
struct process_start_data struct process_start_data
{ {
char *cmd; /* Pointer to a copy of the command used to execute the process.
Allocated a page that must be freed by process_start. */
char *cmd_saveptr; /* Value pointed to by 'saveptr' argument used by char *cmd_saveptr; /* Value pointed to by 'saveptr' argument used by
successive calls to strtok_r to split 'cmd' into successive calls to strtok_r to split 'cmd' into
tokens while maintaining state. */ tokens while maintaining state. */
@@ -90,26 +88,22 @@ process_execute (const char *cmd)
/* Create a new thread to execute the command, by initializing /* Create a new thread to execute the command, by initializing
it running the function 'start_process' with the appropriate it running the function 'start_process' with the appropriate
arguments. For details of arguments, see 'start_process'. */ arguments. For details of arguments, see 'start_process'. */
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); sema_init (&data.loaded, 0);
data.success = false; data.success = false;
tid = thread_create (file_name, PRI_DEFAULT, start_process, &data); tid = thread_create (file_name, PRI_DEFAULT, start_process, &data);
/* Return TID_ERROR and free resources if starting execution went wrong. */ /* Wait until process file has finished attempting to load via the child
if (tid == TID_ERROR) thread before reporting success of starting execution. */
palloc_free_page (cmd_copy); if (tid != TID_ERROR)
else
{ {
/* Wait until process file has finished attempting to load via the child
thread before reporting success of starting execution. */
sema_down (&data.loaded); sema_down (&data.loaded);
if (!data.success) if (!data.success)
tid = TID_ERROR; tid = TID_ERROR;
} }
palloc_free_page (cmd_copy);
return tid; return tid;
} }
@@ -158,7 +152,6 @@ start_process (void *proc_start_data)
/* If load failed, quit. */ /* If load failed, quit. */
if (!data->success) if (!data->success)
{ {
palloc_free_page (data->cmd);
sema_up (&data->loaded); sema_up (&data->loaded);
thread_exit (); thread_exit ();
} }
@@ -167,7 +160,6 @@ start_process (void *proc_start_data)
command that executed the process. */ command that executed the process. */
data->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; bool success = data->success;
palloc_free_page (data->cmd);
sema_up (&data->loaded); sema_up (&data->loaded);
/* If stack initialization failed, free resources and quit. */ /* If stack initialization failed, free resources and quit. */