133 lines
4.2 KiB
C
133 lines
4.2 KiB
C
/*-
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* Copyright (c) 1991 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)crt0.c 5.6 (Berkeley) 7/3/91";
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#endif /* not lint */
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/*
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* C start up routine.
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* Robert Henry, UCB, 20 Oct 81
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*
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* We make the following (true) assumptions:
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* 1) when the kernel calls start, it does a jump to location 2,
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* and thus avoids the register save mask. We are NOT called
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* with a calls! see sys1.c:setregs().
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* 2) The only register variable that we can trust is sp,
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* which points to the base of the kernel calling frame.
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* Do NOT believe the documentation in exec(2) regarding the
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* values of fp and ap.
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* 3) We can allocate as many register variables as we want,
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* and don't have to save them for anybody.
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* 4) Because of the ways that asm's work, we can't have
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* any automatic variables allocated on the stack, because
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* we must catch the value of sp before any automatics are
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* allocated.
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*/
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char **environ = (char **)0;
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static int fd;
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extern unsigned char etext;
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extern unsigned char eprol asm ("eprol");
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extern start() asm("start");
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asm(".text; orb #0,d0"); /* 32 bits of zero at location 0 */
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start()
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{
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struct kframe {
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int kargc;
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char *kargv[1]; /* size depends on kargc */
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char kargstr[1]; /* size varies */
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char kenvstr[1]; /* size varies */
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};
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/*
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* ALL REGISTER VARIABLES!!!
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*/
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register struct kframe *kfp; /* r10 */
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register char **targv;
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register char **argv;
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extern int errno;
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extern void _mcleanup();
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#ifdef lint
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kfp = 0;
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initcode = initcode = 0;
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#else not lint
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asm("lea a6@(4),%0" : "=r" (kfp)); /* catch it quick */
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#endif not lint
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for (argv = targv = &kfp->kargv[0]; *targv++; /* void */)
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/* void */ ;
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if (targv >= (char **)(*argv))
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--targv;
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environ = targv;
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asm("eprol:");
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#ifdef paranoid
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/*
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* The standard I/O library assumes that file descriptors 0, 1, and 2
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* are open. If one of these descriptors is closed prior to the start
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* of the process, I/O gets very confused. To avoid this problem, we
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* insure that the first three file descriptors are open before calling
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* main(). Normally this is undefined, as it adds two unnecessary
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* system calls.
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*/
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do {
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fd = open("/dev/null", 2);
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} while (fd >= 0 && fd < 3);
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close(fd);
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#endif paranoid
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#ifdef MCRT0
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atexit(_mcleanup);
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monstartup(&eprol, &etext);
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#endif MCRT0
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errno = 0;
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exit(main(kfp->kargc, argv, environ));
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}
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#ifdef CRT0
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/*
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* null mcount and moncontrol,
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* just in case some routine is compiled for profiling
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*/
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moncontrol(val)
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int val;
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{
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}
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asm(".globl mcount");
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asm("mcount: rts");
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#endif CRT0
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