forked from ariadne/libucontext
63 lines
1.9 KiB
C
63 lines
1.9 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <stdarg.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include "defs.h"
|
||
|
|
#include <libucontext/libucontext.h>
|
||
|
|
|
||
|
|
|
||
|
|
extern void libucontext_trampoline(void);
|
||
|
|
|
||
|
|
|
||
|
|
void
|
||
|
|
libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
|
||
|
|
{
|
||
|
|
libucontext_greg_t *sp, *regp;
|
||
|
|
va_list va;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
/* set up and align the stack. */
|
||
|
|
sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
|
||
|
|
sp -= argc < 8 ? 0 : argc - 8;
|
||
|
|
sp = (libucontext_greg_t *) (((uintptr_t) sp & -16L));
|
||
|
|
|
||
|
|
/* set up the ucontext structure */
|
||
|
|
ucp->uc_mcontext.__gregs[REG_RA] = (libucontext_greg_t) libucontext_trampoline;
|
||
|
|
ucp->uc_mcontext.__gregs[REG_S0] = 0;
|
||
|
|
ucp->uc_mcontext.__gregs[REG_S1] = (libucontext_greg_t) ucp->uc_link;
|
||
|
|
ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp;
|
||
|
|
ucp->uc_mcontext.__gregs[REG_PC] = (libucontext_greg_t) func;
|
||
|
|
|
||
|
|
va_start(va, argc);
|
||
|
|
|
||
|
|
/* first 8 args go in $a0 through $a7. */
|
||
|
|
regp = &(ucp->uc_mcontext.__gregs[REG_A0]);
|
||
|
|
|
||
|
|
for (i = 0; (i < argc && i < 8); i++)
|
||
|
|
*regp++ = va_arg (va, libucontext_greg_t);
|
||
|
|
|
||
|
|
/* remainder overflows into stack */
|
||
|
|
for (; i < argc; i++)
|
||
|
|
*sp++ = va_arg (va, libucontext_greg_t);
|
||
|
|
|
||
|
|
va_end(va);
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef EXPORT_UNPREFIXED
|
||
|
|
extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
|
||
|
|
extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
|
||
|
|
#endif
|