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/* $NetBSD: crt0-common.c,v 1.27 2022/06/21 06:52:17 skrll Exp $ */
/*
* Copyright (c) 1998 Christos Zoulas
* Copyright (c) 1995 Christopher G. Demetriou
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the
* NetBSD Project. See http://www.NetBSD.org/ for
* information about NetBSD.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: crt0-common.c,v 1.27 2022/06/21 06:52:17 skrll Exp $");
#include <sys/types.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <sys/syscall.h>
#include <machine/profile.h>
#include <stdlib.h>
#include <unistd.h>
#include "csu-common.h"
extern int main(int, char **, char **);
typedef void (*fptr_t)(void);
#ifndef HAVE_INITFINI_ARRAY
extern void _init(void);
extern void _fini(void);
#endif
extern void _libc_init(void);
/*
* Arrange for _DYNAMIC to be weak and undefined (and therefore to show up
* as being at address zero, unless something else defines it). That way,
* if we happen to be compiling without -static but with without any
* shared libs present, things will still work.
*/
__weakref_visible int rtld_DYNAMIC __weak_reference(_DYNAMIC);
#ifdef MCRT0
extern void monstartup(u_long, u_long);
extern void _mcleanup(void);
extern unsigned char __etext, __eprol;
#endif /* MCRT0 */
static char empty_string[] = "";
char **environ __common;
struct ps_strings *__ps_strings __common = 0;
char *__progname __common = empty_string;
__dead __dso_hidden void ___start(void (*)(void), struct ps_strings *);
#define write(fd, s, n) __syscall(SYS_write, (fd), (s), (n))
#define _FATAL(str) \
do { \
write(2, str, sizeof(str)-1); \
_exit(1); \
} while (0)
/*
* If we are using INIT_ARRAY/FINI_ARRAY and we are linked statically,
* we have to process these instead of relying on RTLD to do it for us.
*
* Since we don't need .init or .fini sections, just code them in C
* to make life easier.
*/
extern const fptr_t __preinit_array_start[] __dso_hidden;
extern const fptr_t __preinit_array_end[] __dso_hidden __weak;
extern const fptr_t __init_array_start[] __dso_hidden;
extern const fptr_t __init_array_end[] __dso_hidden __weak;
extern const fptr_t __fini_array_start[] __dso_hidden;
extern const fptr_t __fini_array_end[] __dso_hidden __weak;
static inline void
_preinit(void)
{
for (const fptr_t *f = __preinit_array_start; f < __preinit_array_end; f++) {
(*f)();
}
}
static inline void
_initarray(void)
{
for (const fptr_t *f = __init_array_start; f < __init_array_end; f++) {
(*f)();
}
}
static void
_finiarray(void)
{
for (const fptr_t *f = __fini_array_start; f < __fini_array_end; f++) {
(*f)();
}
}
#if \
defined(__aarch64__) || \
defined(__powerpc__) || \
defined(__sparc__) || \
defined(__x86_64__)
#define HAS_IPLTA
static void fix_iplta(void) __noinline;
#elif \
defined(__arm__) || \
defined(__i386__)
#define HAS_IPLT
static void fix_iplt(void) __noinline;
#endif
#ifdef HAS_IPLTA
#include <stdio.h>
extern const Elf_Rela __rela_iplt_start[] __dso_hidden __weak;
extern const Elf_Rela __rela_iplt_end[] __dso_hidden __weak;
#ifdef __sparc__
#define IFUNC_RELOCATION R_TYPE(JMP_IREL)
#include <machine/elf_support.h>
#define write_plt(where, value) sparc_write_branch((void *)where, (void *)value)
#else
#define IFUNC_RELOCATION R_TYPE(IRELATIVE)
#define write_plt(where, value) *where = value
#endif
static void
fix_iplta(void)
{
const Elf_Rela *rela, *relalim;
uintptr_t relocbase = 0;
Elf_Addr *where, target;
rela = __rela_iplt_start;
relalim = __rela_iplt_end;
for (; rela < relalim; ++rela) {
if (ELF_R_TYPE(rela->r_info) != IFUNC_RELOCATION)
abort();
where = (Elf_Addr *)(relocbase + rela->r_offset);
target = (Elf_Addr)(relocbase + rela->r_addend);
target = ((Elf_Addr(*)(void))target)();
write_plt(where, target);
}
}
#endif
#ifdef HAS_IPLT
extern const Elf_Rel __rel_iplt_start[] __dso_hidden __weak;
extern const Elf_Rel __rel_iplt_end[] __dso_hidden __weak;
#define IFUNC_RELOCATION R_TYPE(IRELATIVE)
static void
fix_iplt(void)
{
const Elf_Rel *rel, *rellim;
uintptr_t relocbase = 0;
Elf_Addr *where, target;
rel = __rel_iplt_start;
rellim = __rel_iplt_end;
for (; rel < rellim; ++rel) {
if (ELF_R_TYPE(rel->r_info) != IFUNC_RELOCATION)
abort();
where = (Elf_Addr *)(relocbase + rel->r_offset);
target = ((Elf_Addr(*)(void))*where)();
*where = target;
}
}
#endif
#if defined(__x86_64__) || defined(__i386__)
# define HAS_RELOCATE_SELF
# if defined(__x86_64__)
# define RELA
# define REL_TAG DT_RELA
# define RELSZ_TAG DT_RELASZ
# define REL_TYPE Elf_Rela
# else
# define REL_TAG DT_REL
# define RELSZ_TAG DT_RELSZ
# define REL_TYPE Elf_Rel
# endif
#include <elf.h>
static void relocate_self(struct ps_strings *) __noinline;
static void
relocate_self(struct ps_strings *ps_strings)
{
AuxInfo *aux = (AuxInfo *)(ps_strings->ps_argvstr + ps_strings->ps_nargvstr +
ps_strings->ps_nenvstr + 2);
uintptr_t relocbase = (uintptr_t)~0U;
const Elf_Phdr *phdr = NULL;
Elf_Half phnum = (Elf_Half)~0;
for (; aux->a_type != AT_NULL; ++aux) {
switch (aux->a_type) {
case AT_BASE:
if (aux->a_v)
return;
break;
case AT_PHDR:
phdr = (void *)aux->a_v;
break;
case AT_PHNUM:
phnum = (Elf_Half)aux->a_v;
break;
}
}
if (phdr == NULL || phnum == (Elf_Half)~0)
return;
const Elf_Phdr *phlimit = phdr + phnum, *dynphdr = NULL;
for (; phdr < phlimit; ++phdr) {
if (phdr->p_type == PT_DYNAMIC)
dynphdr = phdr;
if (phdr->p_type == PT_PHDR)
relocbase = (uintptr_t)phdr - phdr->p_vaddr;
}
if (dynphdr == NULL || relocbase == (uintptr_t)~0U)
return;
Elf_Dyn *dynp = (Elf_Dyn *)((uint8_t *)dynphdr->p_vaddr + relocbase);
const REL_TYPE *relocs = 0, *relocslim;
Elf_Addr relocssz = 0;
for (; dynp->d_tag != DT_NULL; dynp++) {
switch (dynp->d_tag) {
case REL_TAG:
relocs =
(const REL_TYPE *)(relocbase + dynp->d_un.d_ptr);
break;
case RELSZ_TAG:
relocssz = dynp->d_un.d_val;
break;
}
}
relocslim = (const REL_TYPE *)((const uint8_t *)relocs + relocssz);
for (; relocs < relocslim; ++relocs) {
Elf_Addr *where;
where = (Elf_Addr *)(relocbase + relocs->r_offset);
switch (ELF_R_TYPE(relocs->r_info)) {
case R_TYPE(RELATIVE): /* word64 B + A */
#ifdef RELA
*where = (Elf_Addr)(relocbase + relocs->r_addend);
#else
*where += (Elf_Addr)relocbase;
#endif
break;
#ifdef IFUNC_RELOCATION
case IFUNC_RELOCATION:
break;
#endif
default:
abort();
}
}
}
#endif
void
___start(void (*cleanup)(void), /* from shared loader */
struct ps_strings *ps_strings)
{
#if defined(HAS_RELOCATE_SELF)
relocate_self(ps_strings);
#endif
if (ps_strings == NULL)
_FATAL("ps_strings missing\n");
__ps_strings = ps_strings;
environ = ps_strings->ps_envstr;
if (ps_strings->ps_argvstr[0] != NULL) {
char *c;
__progname = ps_strings->ps_argvstr[0];
for (c = ps_strings->ps_argvstr[0]; *c; ++c) {
if (*c == '/')
__progname = c + 1;
}
} else {
__progname = empty_string;
}
if (cleanup != NULL)
atexit(cleanup);
_libc_init();
if (&rtld_DYNAMIC == NULL) {
#ifdef HAS_IPLTA
fix_iplta();
#endif
#ifdef HAS_IPLT
fix_iplt();
#endif
}
_preinit();
#ifdef MCRT0
atexit(_mcleanup);
monstartup((u_long)&__eprol, (u_long)&__etext);
#endif
atexit(_finiarray);
_initarray();
#ifndef HAVE_INITFINI_ARRAY
atexit(_fini);
_init();
#endif
exit(main(ps_strings->ps_nargvstr, ps_strings->ps_argvstr, environ));
}
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