xref: /csrg-svn/sys/kern/sys_process.c (revision 65771)

/*-
 * Copyright (c) 1982, 1986, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * %sccs.include.proprietary.c%
 *
 *	@(#)sys_process.c	8.5 (Berkeley) 01/21/94
 */

#define IPCREG
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/buf.h>
#include <sys/ptrace.h>

#include <machine/reg.h>
#include <machine/psl.h>
#include <vm/vm.h>
#include <vm/vm_page.h>

#include <sys/user.h>

/*
 * Priority for tracing
 */
#define	IPCPRI	PZERO

/*
 * Tracing variables.
 * Used to pass trace command from
 * parent to child being traced.
 * This data base cannot be
 * shared and is locked
 * per user.
 */
struct {
	int	ip_lock;
	int	ip_req;
	caddr_t	ip_addr;
	int	ip_data;
} ipc;

/*
 * Process debugging system call.
 */
struct ptrace_args {
	int	req;
	pid_t	pid;
	caddr_t	addr;
	int	data;
};
ptrace(curp, uap, retval)
	struct proc *curp;
	register struct ptrace_args *uap;
	int *retval;
{
	register struct proc *p;
	int error;

	if (uap->req <= 0) {
		curp->p_flag |= P_TRACED;
		return (0);
	}
	p = pfind(uap->pid);
	if (p == 0)
		return (ESRCH);
	if (uap->req == PT_ATTACH) {
		/*
		 * Must be root if the process has used set user or group
		 * privileges or does not belong to the real user.  Must
		 * not be already traced.  Can't attach to ourselves.
		 */
		if ((p->p_flag & P_SUGID ||
		    p->p_cred->p_ruid != curp->p_cred->p_ruid) &&
		    (error = suser(p->p_ucred, &p->p_acflag)) != 0)
			return (error);
		if (p->p_flag & P_TRACED)
			return (EALREADY);	/* ??? */
		if (p->p_pid == curp->p_pid)
			return (EINVAL);
		/*
		 * It would be nice if the tracing relationship was separate
		 * from the parent relationship but that would require
		 * another set of links in the proc struct or for "wait"
		 * to scan the entire proc table.  To make life easier,
		 * we just re-parent the process we're trying to trace.
		 * The old parent is remembered so we can put things back
		 * on a "detach".
		 */
		p->p_flag |= P_TRACED;
		p->p_oppid = p->p_pptr->p_pid;
		proc_reparent(p, curp);
		psignal(p, SIGSTOP);
		return (0);
	}
	if (p->p_stat != SSTOP || p->p_pptr != curp || !(p->p_flag & P_TRACED))
		return (ESRCH);
	while (ipc.ip_lock)
		sleep((caddr_t)&ipc, IPCPRI);
	ipc.ip_lock = p->p_pid;
	ipc.ip_data = uap->data;
	ipc.ip_addr = uap->addr;
	ipc.ip_req = uap->req;
	p->p_flag &= ~P_WAITED;
	while (ipc.ip_req > 0) {
		if (p->p_stat==SSTOP)
			setrunnable(p);
		sleep((caddr_t)&ipc, IPCPRI);
	}
	*retval = ipc.ip_data;
	ipc.ip_lock = 0;
	wakeup((caddr_t)&ipc);
	if (ipc.ip_req < 0)
		return (EIO);
	return (0);
}

#define	PHYSOFF(p, o) ((caddr_t)(p) + (o))
#if defined(hp300) || defined(luna68k)
#define PHYSALIGNED(a) (((int)(a) & (sizeof(short) - 1)) == 0)
#else
#define PHYSALIGNED(a) (((int)(a) & (sizeof(int) - 1)) == 0)
#endif

#if defined(i386)
#undef        PC
#undef        SP
#undef        PS
#undef        R0
#undef        R1

#define       PC      tEIP
#define       SP      tESP
#define       PS      tEFLAGS
#define       R0      tEDX
#define       R1      tECX
#endif

/*
 * Transmit a tracing request from the parent to the child process
 * being debugged. This code runs in the context of the child process
 * to fulfill the command requested by the parent.
 */
trace_req(p)
	register struct proc *p;
{
	register int i, *poff, *regs;
	extern char kstack[];

	if (ipc.ip_lock != p->p_pid)
		return (0);
	p->p_slptime = 0;
	regs = p->p_md.md_regs;
	p->p_addr->u_kproc.kp_proc.p_md.md_regs = regs; /* u.u_ar0 */
	i = ipc.ip_req;
	ipc.ip_req = 0;
	switch (i) {

	case PT_READ_I:			/* read the child's text space */
		if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ))
			goto error;
		ipc.ip_data = fuiword((caddr_t)ipc.ip_addr);
		break;

	case PT_READ_D:			/* read the child's data space */
		if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ))
			goto error;
		ipc.ip_data = fuword((caddr_t)ipc.ip_addr);
		break;

	case PT_READ_U:			/* read the child's u. */
		i = (int)ipc.ip_addr;
		if ((u_int) i > ctob(UPAGES)-sizeof(int) || !PHYSALIGNED(i))
			goto error;
		ipc.ip_data = *(int *)PHYSOFF(p->p_addr, i);
		break;

	case PT_WRITE_I:		/* write the child's text space */
		if ((i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data)) < 0) {
			vm_offset_t sa, ea;
			int rv;

			sa = trunc_page((vm_offset_t)ipc.ip_addr);
			ea = round_page((vm_offset_t)ipc.ip_addr+sizeof(int));
			rv = vm_map_protect(&p->p_vmspace->vm_map, sa, ea,
					VM_PROT_DEFAULT, FALSE);
			if (rv == KERN_SUCCESS) {
				i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data);
				(void) vm_map_protect(&p->p_vmspace->vm_map,
					sa, ea, VM_PROT_READ|VM_PROT_EXECUTE,
					FALSE);
			}
		}
		if (i < 0)
			goto error;
		break;

	case PT_WRITE_D:		/* write the child's data space */
		if (suword((caddr_t)ipc.ip_addr, 0) < 0)
			goto error;
		(void) suword((caddr_t)ipc.ip_addr, ipc.ip_data);
		break;

	case PT_WRITE_U:		/* write the child's u. */
		i = (int)ipc.ip_addr;
#ifdef mips
		poff = (int *)PHYSOFF(p->p_addr, i);
#else
		poff = (int *)PHYSOFF(kstack, i);
#endif
		for (i=0; i<NIPCREG; i++)
			if (poff == &regs[ipcreg[i]])
				goto ok;
#if defined(hp300) || defined(luna68k)
		/*
		 * In the new frame layout, PS/PC are skewed by 2 bytes.
		 */
		regs = (int *)((short *)regs + 1);
		if (poff == &regs[PC])
			goto ok;
#endif
		if (poff == &regs[PS]) {
			ipc.ip_data |= PSL_USERSET;
			ipc.ip_data &= ~PSL_USERCLR;
#ifdef PSL_CM_CLR
			if (ipc.ip_data & PSL_CM)
				ipc.ip_data &= ~PSL_CM_CLR;
#endif
			goto ok;
		}
#if defined(hp300) || defined(luna68k)
#ifdef FPCOPROC
		if (poff >= (int *)&((struct user *)kstack)->u_pcb.pcb_fpregs.fpf_regs &&
		    poff <= (int *)&((struct user *)kstack)->u_pcb.pcb_fpregs.fpf_fpiar)
			goto ok;
#endif
#endif
		goto error;

	ok:
		*poff = ipc.ip_data;
		break;

	case PT_STEP:			/* single step the child */
	case PT_CONTINUE:		/* continue the child */
#ifndef mips
		regs = (int *)((short *)regs + 1);
#endif
		if ((unsigned)ipc.ip_data >= NSIG)
			goto error;
		if ((int)ipc.ip_addr != 1)
			regs[PC] = (int)ipc.ip_addr;
		p->p_xstat = ipc.ip_data;	/* see issignal */
#ifdef mips
		if (i == PT_STEP && cpu_singlestep(p))
			goto error;
#else
#ifdef PSL_T
		/* need something more machine independent here... */
		if (i == PT_STEP)
			regs[PS] |= PSL_T;
#endif
#endif
		wakeup((caddr_t)&ipc);
		return (1);

	case PT_KILL:			/* kill the child process */
		wakeup((caddr_t)&ipc);
		exit1(p, (int)p->p_xstat);

	case PT_DETACH:			/* stop tracing the child */
		regs = (int *)((short *)regs + 1);
		if ((unsigned)ipc.ip_data >= NSIG)
			goto error;
		if ((int)ipc.ip_addr != 1)
			regs[PC] = (int)ipc.ip_addr;
		p->p_xstat = ipc.ip_data;	/* see issignal */
		p->p_flag &= ~P_TRACED;
		if (p->p_oppid != p->p_pptr->p_pid) {
                        register struct proc *pp = pfind(p->p_oppid);

                        if (pp)
                                proc_reparent(p, pp);
		}
		p->p_oppid = 0;
		wakeup((caddr_t)&ipc);
		return (1);

	default:
	error:
		ipc.ip_req = -1;
	}
	wakeup((caddr_t)&ipc);
	return (0);
}