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Implement basic syscall_handler using the lookup table, w/ E

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This commit is contained in:
sBubshait
2024-11-03 23:47:22 +00:00
parent 87126237ad
commit d626b7a392
1 changed files with 21 additions and 3 deletions
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24
src/userprog/syscall.c
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@@ -17,6 +17,8 @@ typedef uintptr_t (*syscall_function) (uintptr_t, uintptr_t, uintptr_t);
static void halt (void); static void halt (void);
static void exit (int status); static void exit (int status);
static void *validate_user_pointer(void *ptr, size_t size);
/* A struct defining a pair of a syscall_function along with its arity. */ /* A struct defining a pair of a syscall_function along with its arity. */
typedef struct { typedef struct {
syscall_function function; syscall_function function;
@@ -29,6 +31,9 @@ static const syscall_arguments syscall_lookup[] = {
[SYS_EXIT] = {(syscall_function) exit, 1}, [SYS_EXIT] = {(syscall_function) exit, 1},
}; };
static const int lookup_size
= sizeof (syscall_lookup) / sizeof (syscall_arguments);
void void
syscall_init (void) syscall_init (void)
{ {
@@ -36,10 +41,23 @@ syscall_init (void)
} }
static void static void
syscall_handler (struct intr_frame *f UNUSED) syscall_handler (struct intr_frame *f)
{ {
printf ("system call!\n"); validate_user_pointer(f->esp, 1);
thread_exit (); int syscall_number = *(int *) f->esp;
if (syscall_number < 0 || syscall_number >= lookup_size)
thread_exit ();
syscall_arguments syscall = syscall_lookup[syscall_number];
validate_user_pointer (f->esp, syscall.arity);
uintptr_t args[3];
for (int i=0; i < syscall.arity; i++)
args[i] = *(uintptr_t *) (f->esp + 1 + i);
f->eax = syscall.function(args[0], args[1], args[2]);
} }
static void static void