xref: /src/lib/csu/common/crt0-common.c

/* $NetBSD: crt0-common.c,v 1.3 2011/02/18 23:37:36 joerg 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 1.3 2011/02/18 23:37:36 joerg Exp $");

#include <sys/types.h>
#include <sys/syscall.h>
#include <machine/profile.h>
#include <stdlib.h>
#include <unistd.h>

#include "rtld.h"

extern int main(int, char **, char **);

extern void	_init(void);
extern void	_fini(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.
 */

#if __GNUC_PREREQ__(4,2)
static int rtld_DYNAMIC __attribute__((__weakref__, __alias__("_DYNAMIC")));
#define	DYNAMIC_SYM	rtld_DYNAMIC
#else
extern int _DYNAMIC __weak_reference(_DYNAMIC);
#define	DYNAMIC_SYM	_DYNAMIC
#endif

#ifdef MCRT0
extern void	monstartup(u_long, u_long);
extern void	_mcleanup(void);
extern unsigned char __etext, __eprol;
#endif /* MCRT0 */

char		**environ;
struct ps_strings *__ps_strings = 0;

static char	 empty_string[] = "";
char		*__progname = empty_string;

void		___start(int, char **, char **, void (*)(void),
    const Obj_Entry *, 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)

void
___start(int argc, char **argv, char **envp,
    void (*cleanup)(void),			/* from shared loader */
    const Obj_Entry *obj,			/* from shared loader */
    struct ps_strings *ps_strings)
{
	environ = envp;

	if (argv[0] != NULL) {
		char *c;
		__progname = argv[0];
		for (c = argv[0]; *c; ++c) {
			if (*c == '/')
				__progname = c + 1;
		}
	} else {
		__progname = empty_string;
	}

	if (ps_strings != NULL)
		__ps_strings = ps_strings;

	if (&DYNAMIC_SYM != NULL) {
		if (obj == NULL)
			_FATAL("NULL Obj_Entry pointer in GOT\n");
		if (obj->magic != RTLD_MAGIC)
			_FATAL("Corrupt Obj_Entry pointer in GOT\n");
		if (obj->version != RTLD_VERSION)
			_FATAL("Dynamic linker version mismatch\n");
		atexit(cleanup);
	}

#ifdef MCRT0
	atexit(_mcleanup);
	monstartup((u_long)&__eprol, (u_long)&__etext);
#endif

	atexit(_fini);
	_init();

	exit(main(argc, argv, environ));
}