create.c,v

来自「TCP-IP红宝书源代码」· C,V 代码 · 共 316 行

head	1.5;
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comment	@ * @;


1.5
date	97.09.21.19.29.30;	author dls;	state Dist;
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next	1.4;

1.4
date	94.05.07.19.26.36;	author dls;	state Works;
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1.3
date	94.05.06.03.12.23;	author dls;	state Works;
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1.2
date	94.05.06.02.31.36;	author dls;	state Old;
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1.1
date	94.05.01.16.07.01;	author dls;	state Works;
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desc
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1.5
log
@pre-3e code
@
text
@/* create.c - create, newpid */
    
#include <conf.h>
#include <i386.h>
#include <kernel.h>
#include <proc.h>
#include <sem.h>
#include <mem.h>
#include <io.h>

static unsigned long esp;

/*------------------------------------------------------------------------
 *  create  -  create a process to start running a procedure
 *------------------------------------------------------------------------
 */
SYSCALL create(procaddr,ssize,priority,name,nargs,args)
	int	*procaddr;		/* procedure address		*/
	int	ssize;			/* stack size in words		*/
	int	priority;		/* process priority > 0		*/
	char	*name;			/* name (for debugging)		*/
	int	nargs;			/* number of args that follow	*/
	long	args;			/* arguments (treated like an	*/
					/* array in the code)		*/
{
	unsigned long	savsp, *pushsp;
	STATWORD 	ps;    
	int		pid;		/* stores new process id	*/
	struct	pentry	*pptr;		/* pointer to proc. table entry */
	int		i;
	unsigned long	*a;		/* points to list of args	*/
	unsigned long	*saddr;		/* stack address		*/
	unsigned long   *getstk();
	int		INITRET();

	disable(ps);
	if (ssize < MINSTK)
		ssize = MINSTK;
	ssize = (int) roundew(ssize);
	if (((saddr = (unsigned long *)getstk(ssize)) ==
	    (unsigned long *)SYSERR ) ||
	    (pid=newpid()) == SYSERR || priority < 1 ) {
		restore(ps);
		return(SYSERR);
	}

	numproc++;
	pptr = &proctab[pid];

	pptr->fildes[0] = 0;	/* stdin set to console */
	pptr->fildes[1] = 0;	/* stdout set to console */
	pptr->fildes[2] = 0;	/* stderr set to console */

	for (i=3; i < _NFILE; i++)	/* others set to unused */
		pptr->fildes[i] = FDFREE;

	pptr->pstate = PRSUSP;
	for (i=0 ; i<PNMLEN && (int)(pptr->pname[i]=name[i])!=0 ; i++)
		;
	pptr->pprio = priority;
	pptr->pbase = (long) saddr;
	pptr->pstklen = ssize;
	pptr->psem = 0;
	pptr->phasmsg = FALSE;
	pptr->plimit = pptr->pbase - ssize + sizeof (long);	
	pptr->pirmask[0] = 0;
	pptr->pnxtkin = BADPID;
	pptr->pdevs[0] = pptr->pdevs[1] = BADDEV;

		/* Bottom of stack */
	*saddr = MAGIC;
	savsp = (unsigned long)saddr;

	/* push arguments */
	pptr->pargs = nargs;
	a = (unsigned long *)(&args) + (nargs-1); /* last argument	*/
	for ( ; nargs > 0 ; nargs--)	/* machine dependent; copy args	*/
		*--saddr = *a--;	/* onto created process' stack	*/
	*--saddr = (long)INITRET;	/* push on return address	*/

	*--saddr = pptr->paddr = (long)procaddr; /* where we "ret" to	*/
	*--saddr = savsp;		/* fake frame ptr for procaddr	*/
	savsp = (unsigned long) saddr;

/* this must match what ctxsw expects: flags, regs, old SP */
/* emulate 386 "pushal" instruction */
	*--saddr = 0;
	*--saddr = 0;	/* %eax */
	*--saddr = 0;	/* %ecx */
	*--saddr = 0;	/* %edx */
	*--saddr = 0;	/* %ebx */
	*--saddr = 0;	/* %esp; fill in below */
	pushsp = saddr;
	*--saddr = savsp;	/* %ebp */
	*--saddr = 0;		/* %esi */
	*--saddr = 0;		/* %edi */
	*pushsp = pptr->pesp = (unsigned long)saddr;

	restore(ps);
	return(pid);
}

/*------------------------------------------------------------------------
 * newpid  --  obtain a new (free) process id
 *------------------------------------------------------------------------
 */
LOCAL	newpid()
{
	int	pid;			/* process id to return		*/
	int	i;

	for (i=0 ; i<NPROC ; i++) {	/* check all NPROC slots	*/
		if ( (pid=nextproc--) <= 0)
			nextproc = NPROC-1;
		if (proctab[pid].pstate == PRFREE)
			return(pid);
	}
	return(SYSERR);
}
@


1.4
log
@*** empty log message ***
@
text
@a25 1
	struct sd	*psd;
d27 2
a28 2
	STATWORD ps;    
	int	pid;			/* stores new process id	*/
d30 5
a34 5
	int	i, base;
	unsigned long	*a;			/* points to list of args	*/
	unsigned long	*saddr;			/* stack address		*/
	unsigned long    *getstk();
	int	INITRET();
d40 3
a42 2
	if (((saddr = getstk(ssize)) == (long *)SYSERR ) ||
		(pid=newpid()) == SYSERR || priority < 1 ) {
a45 1
kprintf("in create, newpid %d\n", pid);
d72 1
a72 1
	savsp = saddr;
d76 1
a76 1
	a = (&args) + (nargs-1);	/* point to last argument	*/
d83 1
a83 1
	savsp = saddr;
@


1.3
log
@*** empty log message ***
@
text
@d46 1
a46 1
kprintf("getstk returns %d (%X) ssize %d\n", saddr, saddr, ssize);
a69 2
kprintf("pbase %X plimit %X pstklen %d\n", pptr->pbase, pptr->plimit,
pptr->pstklen);
a70 2
asm("movl	%esp,_esp");
kprintf("create esp before %X\n", esp);
a71 1
kprintf("setting %X to %X (MAGIC)\n", saddr, MAGIC);
a98 1
kprintf("base %d (%X) saddr last %d (%X)\n", pptr->pbase, pptr->pbase,saddr, saddr);
@


1.2
log
@*** empty log message ***
@
text
@a85 11
	*--saddr = savsp;		/* frame pointer for INITRET	*/
	savsp = saddr;
	/*
	 * At this point, the stack looks like a call of the new process
	 * by INITRET(). Now push frame for call to ctxsw and the saved
	 * state that ctxsw expects to restore. 
	 */
	*--saddr = (unsigned long)&pptr->pirmask; /* arg4 to ctxsw; new mask */
	*--saddr = (unsigned long)&pptr->pesp;	 /* arg3 to ctxsw; newsp */
	*--saddr = 0;		/* space for fake oldsp			*/
	*--saddr = 0;		/* space for fake oldmask		*/
d88 2
a89 1
	*--saddr = savsp;		/* fake frame ptr for ctxsw	*/
@


1.1
log
@Initial revision
@
text
@d11 2
d23 1
a23 1
	WORD	args;			/* arguments (treated like an	*/
d27 1
d32 3
a34 3
	WORD	*a;			/* points to list of args	*/
	WORD	*saddr;			/* stack address		*/
	WORD    *getstk();
d41 1
a41 1
	if (((saddr = getstk(ssize)) == (WORD *)SYSERR ) ||
d46 2
a47 2
kprintf("getstk returns %X\n", saddr);
	
d62 1
a62 1
	pptr->pbase = (WORD) saddr;
d66 9
a74 1
	pptr->plimit = pptr->pbase - ssize + sizeof (WORD);	
d76 5
a80 1
	*saddr-- = MAGIC;
a81 6
	for (i=0 ; i<PNREGS ; i++)
		pptr->pregs[i]=INITREG;
/*	pptr->pregs[PC] = pptr->paddr = (WORD)procaddr; */
/*	pptr->pregs[PS] = INITPS; */
	pptr->pnxtkin = BADPID;
	pptr->pdevs[0] = pptr->pdevs[1] = BADDEV;
d83 32
a114 28
	for ( ; nargs > 0 ; nargs--) {	/* machine dependent; copy args	*/
		*saddr-- = *a--;
	}
					/* onto created process' stack	*/
	*saddr = (WORD)INITRET;	/* push on return address	*/
/*	pptr->pregs[SSP] = (WORD)saddr; */

	pptr->segtr.len = sizeof(pptr->segdesc) - 1;
	pptr->segtr.addr = pptr->segdesc;

	psd = &pptr->segdesc[ILSTACK];

	/* set up stack segment descriptor */
	psd->sd_lolimit = ssize;
	psd->sd_hilimit = ssize >> 16;
	base = pptr->plimit - sizeof(WORD);
kprintf("stack base %X limit %d\n", base, ssize);
	psd->sd_lobase = base;
	psd->sd_midbase = base >> 16;
	psd->sd_hibase = base >> 24;
	psd->sd_perm = 3;	/* R/W */
	psd->sd_iscode = 0;
	psd->sd_isapp = 1;
	psd->sd_dpl = 0;
	psd->sd_present = 1;
	psd->sd_avl = 1;
	psd->sd_mbz = 0;
	psd->sd_32b = 1;
@