forked from ariadne/libucontext
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/*
|
|
* Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
|
|
*
|
|
* Permission to use, copy, modify, and/or distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* This software is provided 'as is' and without any warranty, express or
|
|
* implied. In no event shall the authors be liable for any damages arising
|
|
* from the use of this software.
|
|
*/
|
|
|
|
#define _GNU_SOURCE
|
|
#include <stddef.h>
|
|
#include <stdarg.h>
|
|
#include <signal.h>
|
|
#include <string.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
|
|
|
|
extern void __start_context(void);
|
|
|
|
|
|
void
|
|
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
|
|
{
|
|
unsigned long *sp;
|
|
unsigned long *regp;
|
|
va_list va;
|
|
int i;
|
|
|
|
sp = (unsigned long *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
|
|
sp = (unsigned long *) (((uintptr_t) sp & -16L) - 8);
|
|
|
|
if (argc > 4)
|
|
sp -= (argc - 4);
|
|
|
|
ucp->uc_mcontext.arm_sp = (uintptr_t) sp;
|
|
ucp->uc_mcontext.arm_pc = (uintptr_t) func;
|
|
ucp->uc_mcontext.arm_r4 = (uintptr_t) ucp->uc_link;
|
|
ucp->uc_mcontext.arm_lr = (uintptr_t) &__start_context;
|
|
|
|
va_start(va, argc);
|
|
|
|
regp = &(ucp->uc_mcontext.arm_r0);
|
|
|
|
for (i = 0; (i < argc && i < 4); i++)
|
|
*regp++ = va_arg (va, unsigned long);
|
|
|
|
for (; i < argc; i++)
|
|
*sp++ = va_arg (va, unsigned long);
|
|
|
|
va_end(va);
|
|
|
|
/*
|
|
printf("R4 offset = %d\n", offsetof(ucontext_t, uc_mcontext.arm_r4));
|
|
printf("SP offset = %d\n", offsetof(ucontext_t, uc_mcontext.arm_sp));
|
|
printf("LR offset = %d\n", offsetof(ucontext_t, uc_mcontext.arm_lr));
|
|
printf("PC offset = %d\n", offsetof(ucontext_t, uc_mcontext.arm_pc));
|
|
*/
|
|
}
|
|
|
|
|
|
extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
|