freebsd-dev/lib/csu/i386/crt0.c
1994-08-05 17:53:07 +00:00

384 lines
8.3 KiB
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.
*
* $Id: crt0.c,v 1.8 1994/02/13 20:53:11 jkh Exp $
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Erasmus) %G%";
#endif /* LIBC_SCCS and not lint */
extern void exit();
int _callmain();
#include <sys/param.h>
#ifdef DYNAMIC
#include <sys/types.h>
#include <sys/syscall.h>
#include <a.out.h>
#ifndef N_GETMAGIC
#define N_GETMAGIC(x) ((x).a_magic)
#endif
#ifndef N_BSSADDR
#define N_BSSADDR(x) (N_DATADDR(x)+(x).a_data)
#endif
#include <sys/mman.h>
#ifdef sun
#define MAP_COPY MAP_PRIVATE
#define MAP_FILE 0
#define MAP_ANON 0
#else
#ifdef BSD
#if BSD>=199306 && !defined(MAP_FILE)
#define MAP_FILE 0
#endif /* BSD>=199306 */
#endif /* BSD */
#endif /* sun */
#include <link.h>
extern struct _dynamic _DYNAMIC;
static struct ld_entry *ld_entry;
static void __do_dynamic_link ();
static char *_getenv();
static int _strncmp();
#ifdef sun
#define LDSO "/usr/lib/ld.so"
#endif
#ifdef BSD
#define LDSO "/usr/libexec/ld.so"
#endif
#endif /* DYNAMIC */
static char *_strrchr();
char **environ;
#ifdef BSD
extern unsigned char etext;
extern unsigned char eprol asm ("eprol");
extern start() asm("start");
extern mcount() asm ("mcount");
int errno;
static char empty[1];
char *__progname = empty;
#endif
/*
* We need these system calls, but can't use library stubs
*/
#define _exit(v) __syscall(SYS_exit, (int)(v))
#define open(name, f, m) __syscall(SYS_open, (char *)(name), (int)(f), (int)(m))
#define close(fd) __syscall(SYS_close, (int)(fd))
#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), (void *)(s), (size_t)(n))
#define dup(fd) __syscall(SYS_dup, (int)(fd))
#define dup2(fd, fdnew) __syscall(SYS_dup2, (int)(fd), (int)(fdnew))
#ifdef sun
#define mmap(addr, len, prot, flags, fd, off) \
__syscall(SYS_mmap, (addr), (len), (prot), _MAP_NEW|(flags), (fd), (off))
#else
#define mmap(addr, len, prot, flags, fd, off) \
__syscall(SYS_mmap, (caddr_t)(addr), (size_t)(len), (int)(prot), (int)(flags), (int)(fd), (long)0L, (off_t)(off))
#endif
#define _FATAL(str) \
write(2, str, sizeof(str)), \
_exit(1);
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;
extern void _mcleanup();
#ifdef DYNAMIC
volatile caddr_t x;
#endif
#ifdef lint
kfp = 0;
initcode = initcode = 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])
if ((__progname = _strrchr(argv[0], '/')) == NULL)
__progname = argv[0];
else
++__progname;
#ifdef DYNAMIC
/* ld(1) convention: if DYNAMIC = 0 then statically linked */
#ifdef stupid_gcc
if (&_DYNAMIC)
__do_dynamic_link();
#else
x = (caddr_t)&_DYNAMIC;
if (x)
__do_dynamic_link();
#endif
#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 ()
{
struct crt_ldso crt;
struct exec hdr;
char *ldso;
int dupzfd;
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) {
_FATAL("No ld.so\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 = mmap(0, hdr.a_text,
PROT_READ|PROT_EXEC,
MAP_FILE|MAP_COPY,
crt.crt_ldfd, N_TXTOFF(hdr));
if (crt.crt_ba == -1) {
_FATAL("Cannot map ld.so\n");
}
#ifdef BSD
/* !!!
* 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
#undef N_BSSADDR
#define N_DATADDR(x) ((x).a_text)
#define N_BSSADDR(x) ((x).a_text + (x).a_data)
#endif
/* Map in data segment of ld.so writable */
if (mmap(crt.crt_ba+N_DATADDR(hdr), hdr.a_data,
PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_FILE|MAP_COPY,
crt.crt_ldfd, N_DATOFF(hdr)) == -1) {
_FATAL("Cannot map ld.so\n");
}
/* Map bss segment of ld.so zero */
if (hdr.a_bss && mmap(crt.crt_ba+N_BSSADDR(hdr), hdr.a_bss,
PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_ANON|MAP_COPY,
crt.crt_dzfd, 0) == -1) {
_FATAL("Cannot map ld.so\n");
}
crt.crt_dp = &_DYNAMIC;
crt.crt_ep = environ;
crt.crt_bp = (caddr_t)_callmain;
crt.crt_prog = __progname;
entry = (int (*)())(crt.crt_ba + sizeof hdr);
if ((*entry)(CRT_VERSION_BSD_3, &crt) == -1) {
_FATAL("ld.so failed\n");
}
ld_entry = _DYNAMIC.d_entry;
return;
}
/*
* DL stubs
*/
void *
dlopen(name, mode)
char *name;
int mode;
{
if (ld_entry == NULL)
return NULL;
return (ld_entry->dlopen)(name, mode);
}
int
dlclose(fd)
void *fd;
{
if (ld_entry == NULL)
return -1;
return (ld_entry->dlclose)(fd);
}
void *
dlsym(fd, name)
void *fd;
char *name;
{
if (ld_entry == NULL)
return NULL;
return (ld_entry->dlsym)(fd, name);
}
int
dlctl(fd, cmd, arg)
void *fd, *arg;
int cmd;
{
if (ld_entry == NULL)
return -1;
return (ld_entry->dlctl)(fd, cmd, arg);
}
/*
* Support routines
*/
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;
}
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 */
static char *
_strrchr(p, ch)
register char *p, ch;
{
register char *save;
for (save = NULL;; ++p) {
if (*p == ch)
save = (char *)p;
if (!*p)
return(save);
}
/* NOTREACHED */
}
#ifdef MCRT0
asm (" .text");
asm ("_eprol:");
#endif