FreeBSD-5.3/lib/csu/i386/crt0.c
/*
* Copyright (c) 1993 Paul Kranenburg
* 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 by Paul Kranenburg.
* 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.
*
* $FreeBSD: src/lib/csu/i386/crt0.c,v 1.37 2002/03/29 22:43:41 markm Exp $
*/
#include <sys/param.h>
#include <stdlib.h>
#ifdef DYNAMIC
#include <sys/types.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <a.out.h>
#include <link.h>
#include <string.h>
#include "libc_private.h"
/* !!!
* This is gross, ld.so is a ZMAGIC a.out, but has `sizeof(hdr)' for
* an entry point and not at PAGSIZ as the N_*ADDR macros assume.
*/
#undef N_DATADDR
#define N_DATADDR(x) ((x).a_text)
#undef N_BSSADDR
#define N_BSSADDR(x) ((x).a_text + (x).a_data)
#ifndef N_GETMAGIC
#define N_GETMAGIC(x) ((x).a_magic)
#endif /* N_GETMAGIC */
#ifndef MAP_PRIVATE
#define MAP_PRIVATE MAP_COPY
#endif /* MAP_PRIVATE */
#ifndef MAP_FILE
#define MAP_FILE 0
#endif /* MAP_FILE */
#ifndef MAP_ANON
#define MAP_ANON 0
#endif /* MAP_ANON */
#ifdef DEBUG
/*
* We need these two because we are going to call them before the ld.so is
* finished (as a matter of fact before we know if it exists !) so we must
* provide these versions for them
*/
static char *_getenv();
static int _strncmp();
#endif /* DEBUG */
#ifndef LDSO
#define LDSO "/usr/libexec/ld.so"
#endif /* LDSO */
extern struct _dynamic _DYNAMIC;
static void __do_dynamic_link(char **argv);
#endif /* DYNAMIC */
int _callmain();
int errno;
const char *__progname = "";
char **environ;
/* Globals used by dlopen() and related functions in libc */
struct ld_entry *__ldso_entry;
int __ldso_version;
extern unsigned char etext;
extern unsigned char eprol asm ("eprol");
extern start() asm("start");
extern mcount() asm ("mcount");
extern int main(int argc, char **argv, char **envp);
int __syscall(int syscall,...);
#ifdef MCRT0
void monstartup(void *low, void *high);
#endif /* MCRT0 */
/*
* We need these system calls, but can't use library stubs because the are
* not accessible until we have done the ld.so stunt.
*/
#define _exit(v) \
__syscall(SYS_exit, (int)(v))
#define _open(name, f, m) \
__syscall(SYS_open, (const char *)(name), (int)(f), (int)(m))
#define _read(fd, s, n) \
__syscall(SYS_read, (int)(fd), (void *)(s), (size_t)(n))
#define _write(fd, s, n) \
__syscall(SYS_write, (int)(fd), (const void *)(s), (size_t)(n))
#define _mmap(addr, len, prot, flags, fd, off) \
(void *) __syscall(SYS_mmap, (void *)(addr), (size_t)(len), \
(int)(prot), (int)(flags), (int)(fd), 0, (off_t)(off))
#define _PUTNMSG(str, len) _write(2, (str), (len))
#define _PUTMSG(str) _PUTNMSG((str), sizeof (str) - 1)
#define _FATAL(str) ( _PUTMSG(str), _exit(1) )
int
start()
{
struct kframe {
int kargc;
char *kargv[1]; /* size depends on kargc */
char kargstr[1]; /* size varies */
char kenvstr[1]; /* size varies */
};
/*
* ALL REGISTER VARIABLES!!!
*/
register struct kframe *kfp;
register char **targv;
register char **argv;
register const char *s;
extern void _mcleanup();
#ifdef DYNAMIC
volatile caddr_t x;
#endif
#ifdef lint
kfp = 0;
#else /* not lint */
/* just above the saved frame pointer */
asm ("lea 4(%%ebp), %0" : "=r" (kfp) );
#endif /* not lint */
for (argv = targv = &kfp->kargv[0]; *targv++; /* void */)
/* void */ ;
if (targv >= (char **)(*argv))
--targv;
environ = targv;
if (argv[0]) {
__progname = argv[0];
for (s=__progname; *s != '\0'; s++)
if (*s == '/')
__progname = s+1;
}
#ifdef DYNAMIC
/* ld(1) convention: if DYNAMIC = 0 then statically linked */
/* sometimes GCC is too smart/stupid for its own good */
x = (caddr_t)&_DYNAMIC;
if (x)
__do_dynamic_link(argv);
#endif /* DYNAMIC */
asm("eprol:");
#ifdef MCRT0
atexit(_mcleanup);
monstartup(&eprol, &etext);
#endif /* MCRT0 */
asm ("__callmain:"); /* Defined for the benefit of debuggers */
exit(main(kfp->kargc, argv, environ));
}
#ifdef DYNAMIC
static void
__do_dynamic_link(argv)
char **argv;
{
struct crt_ldso crt;
struct exec hdr;
char *ldso;
int (*entry)();
#ifdef DEBUG
/* Provision for alternate ld.so - security risk! */
if (!(ldso = _getenv("LDSO")))
#endif
ldso = LDSO;
crt.crt_ldfd = _open(ldso, 0, 0);
if (crt.crt_ldfd == -1) {
_PUTMSG("Couldn't open ");
_PUTMSG(LDSO);
_FATAL(".\n");
}
/* Read LDSO exec header */
if (_read(crt.crt_ldfd, &hdr, sizeof hdr) < sizeof hdr) {
_FATAL("Failure reading ld.so\n");
}
if ((N_GETMAGIC_NET(hdr) != ZMAGIC) && (N_GETMAGIC(hdr) != QMAGIC)) {
_FATAL("Bad magic: ld.so\n");
}
/* We use MAP_ANON */
crt.crt_dzfd = -1;
/* Map in ld.so */
crt.crt_ba = (int)_mmap(0, hdr.a_text,
PROT_READ|PROT_EXEC,
MAP_FILE|MAP_PRIVATE,
crt.crt_ldfd, N_TXTOFF(hdr));
if (crt.crt_ba == -1) {
_FATAL("Cannot map ld.so (text)\n");
}
/* Map in data segment of ld.so writable */
if ((int)_mmap((caddr_t)(crt.crt_ba+N_DATADDR(hdr)), hdr.a_data,
PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_FILE|MAP_PRIVATE,
crt.crt_ldfd, N_DATOFF(hdr)) == -1) {
_FATAL("Cannot map ld.so (data)\n");
}
/* Map bss segment of ld.so zero */
if (hdr.a_bss && (int)_mmap((caddr_t)(crt.crt_ba+N_BSSADDR(hdr)),
hdr.a_bss,
PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_ANON|MAP_PRIVATE,
crt.crt_dzfd, 0) == -1) {
_FATAL("Cannot map ld.so (bss)\n");
}
crt.crt_dp = &_DYNAMIC;
crt.crt_ep = environ;
crt.crt_bp = (caddr_t)_callmain;
crt.crt_prog = __progname;
crt.crt_ldso = ldso;
crt.crt_ldentry = NULL;
crt.crt_argv = argv;
entry = (int (*)())(crt.crt_ba + sizeof hdr);
__ldso_version = (*entry)(CRT_VERSION_BSD_5, &crt);
__ldso_entry = crt.crt_ldentry;
if (__ldso_version == -1 && __ldso_entry == NULL) {
/* If version 5 not recognised, try version 4 */
__ldso_version = (*entry)(CRT_VERSION_BSD_4, &crt);
__ldso_entry = crt.crt_ldentry;
if (__ldso_version == -1 && __ldso_entry == NULL) {
/* if version 4 not recognised, try version 3 */
__ldso_version = (*entry)(CRT_VERSION_BSD_3, &crt);
__ldso_entry = _DYNAMIC.d_entry;
}
}
if (__ldso_version == -1) {
_PUTMSG("ld.so failed");
if (__ldso_entry != NULL) {
const char *msg = (__ldso_entry->dlerror)();
if(msg != NULL) {
const char *endp;
_PUTMSG(": ");
for(endp = msg; *endp != '\0'; ++endp)
; /* Find the end */
_PUTNMSG(msg, endp - msg);
}
}
_FATAL("\n");
}
if (__ldso_version >= LDSO_VERSION_HAS_DLEXIT)
atexit(__ldso_entry->dlexit);
return;
}
/*
* Support routines
*/
#ifdef DEBUG
static int
_strncmp(s1, s2, n)
register char *s1, *s2;
register n;
{
if (n == 0)
return (0);
do {
if (*s1 != *s2++)
return (*(unsigned char *)s1 - *(unsigned char *)--s2);
if (*s1++ == 0)
break;
} while (--n != 0);
return (0);
}
static char *
_getenv(name)
register char *name;
{
extern char **environ;
register int len;
register char **P, *C;
for (C = name, len = 0; *C && *C != '='; ++C, ++len);
for (P = environ; *P; ++P)
if (!_strncmp(*P, name, len))
if (*(C = *P + len) == '=') {
return(++C);
}
return (char *)0;
}
#endif /* DEBUG */
asm(" ___syscall:");
asm(" popl %ecx");
asm(" popl %eax");
asm(" pushl %ecx");
asm(" .byte 0x9a");
asm(" .long 0");
asm(" .word 7");
asm(" pushl %ecx");
asm(" jc 1f");
asm(" ret");
asm(" 1:");
asm(" movl $-1,%eax");
asm(" ret");
#endif /* DYNAMIC */
/*
* Support routines
*/
#ifdef MCRT0
asm (" .text");
asm ("_eprol:");
#endif