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NetBSD/sys/kern/sys_process.c

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/* $NetBSD: sys_process.c,v 1.65 2000/09/24 07:31:28 erh Exp $ */
/*-
* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
* 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.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*
* from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
*/
/*
* References:
* (1) Bach's "The Design of the UNIX Operating System",
* (2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution,
* (3) the "4.4BSD Programmer's Reference Manual" published
* by USENIX and O'Reilly & Associates.
* The 4.4BSD PRM does a reasonably good job of documenting what the various
* ptrace() requests should actually do, and its text is quoted several times
* in this file.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <sys/user.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <machine/reg.h>
#include <miscfs/procfs/procfs.h>
/* Macros to clear/set/test flags. */
#define SET(t, f) (t) |= (f)
#define CLR(t, f) (t) &= ~(f)
#define ISSET(t, f) ((t) & (f))
/*
* Process debugging system call.
*/
int
sys_ptrace(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_ptrace_args /* {
syscallarg(int) req;
syscallarg(pid_t) pid;
syscallarg(caddr_t) addr;
syscallarg(int) data;
} */ *uap = v;
struct proc *t; /* target process */
struct uio uio;
struct iovec iov;
int s, error, write, tmp;
/* "A foolish consistency..." XXX */
if (SCARG(uap, req) == PT_TRACE_ME)
t = p;
else {
/* Find the process we're supposed to be operating on. */
if ((t = pfind(SCARG(uap, pid))) == NULL)
return (ESRCH);
}
/* Make sure we can operate on it. */
switch (SCARG(uap, req)) {
case PT_TRACE_ME:
/* Saying that you're being traced is always legal. */
break;
case PT_ATTACH:
/*
* You can't attach to a process if:
* (1) it's the process that's doing the attaching,
*/
if (t->p_pid == p->p_pid)
return (EINVAL);
/*
* (2) it's a system process
*/
if (t->p_flag & P_SYSTEM)
return (EPERM);
/*
* (3) it's already being traced, or
*/
if (ISSET(t->p_flag, P_TRACED))
return (EBUSY);
/*
* (4) it's not owned by you, or is set-id on exec
* (unless you're root), or...
*/
if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
ISSET(t->p_flag, P_SUGID)) &&
(error = suser(p->p_ucred, &p->p_acflag)) != 0)
return (error);
/*
* (5) ...it's init, which controls the security level
* of the entire system, and the system was not
* compiled with permanently insecure mode turned on
*/
if (t == initproc && securelevel > -1)
return (EPERM);
/*
* (6) the tracer is chrooted, and its root directory is
* not at or above the root directory of the tracee
*/
if (!proc_isunder(t, p))
return EPERM;
break;
case PT_READ_I:
case PT_READ_D:
case PT_WRITE_I:
case PT_WRITE_D:
case PT_CONTINUE:
case PT_KILL:
case PT_DETACH:
#ifdef PT_STEP
case PT_STEP:
#endif
#ifdef PT_GETREGS
case PT_GETREGS:
#endif
#ifdef PT_SETREGS
case PT_SETREGS:
#endif
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
#endif
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
#endif
/*
* You can't do what you want to the process if:
* (1) It's not being traced at all,
*/
if (!ISSET(t->p_flag, P_TRACED))
return (EPERM);
/*
* (2) it's being traced by procfs (which has
* different signal delivery semantics),
*/
if (ISSET(t->p_flag, P_FSTRACE))
return (EBUSY);
/*
* (3) it's not being traced by _you_, or
*/
if (t->p_pptr != p)
return (EBUSY);
/*
* (4) it's not currently stopped.
*/
if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED))
return (EBUSY);
break;
default: /* It was not a legal request. */
return (EINVAL);
}
/* Do single-step fixup if needed. */
FIX_SSTEP(t);
/* Now do the operation. */
write = 0;
*retval = 0;
tmp = 0;
switch (SCARG(uap, req)) {
case PT_TRACE_ME:
/* Just set the trace flag. */
SET(t->p_flag, P_TRACED);
t->p_oppid = t->p_pptr->p_pid;
return (0);
case PT_WRITE_I: /* XXX no seperate I and D spaces */
case PT_WRITE_D:
write = 1;
tmp = SCARG(uap, data);
case PT_READ_I: /* XXX no seperate I and D spaces */
case PT_READ_D:
/* write = 0 done above. */
iov.iov_base = (caddr_t)&tmp;
iov.iov_len = sizeof(tmp);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = (off_t)(long)SCARG(uap, addr);
uio.uio_resid = sizeof(tmp);
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_procp = p;
error = procfs_domem(p, t, NULL, &uio);
if (!write)
*retval = tmp;
return (error);
#ifdef PT_STEP
case PT_STEP:
/*
* From the 4.4BSD PRM:
* "Execution continues as in request PT_CONTINUE; however
* as soon as possible after execution of at least one
* instruction, execution stops again. [ ... ]"
*/
#endif
case PT_CONTINUE:
case PT_DETACH:
/*
* From the 4.4BSD PRM:
* "The data argument is taken as a signal number and the
* child's execution continues at location addr as if it
* incurred that signal. Normally the signal number will
* be either 0 to indicate that the signal that caused the
* stop should be ignored, or that value fetched out of
* the process's image indicating which signal caused
* the stop. If addr is (int *)1 then execution continues
* from where it stopped."
*/
/* Check that the data is a valid signal number or zero. */
if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG)
return (EINVAL);
PHOLD(t);
#ifdef PT_STEP
/*
* Arrange for a single-step, if that's requested and possible.
*/
error = process_sstep(t, SCARG(uap, req) == PT_STEP);
if (error)
goto relebad;
#endif
/* If the address paramter is not (int *)1, set the pc. */
if ((int *)SCARG(uap, addr) != (int *)1)
if ((error = process_set_pc(t, SCARG(uap, addr))) != 0)
goto relebad;
PRELE(t);
if (SCARG(uap, req) == PT_DETACH) {
/* give process back to original parent or init */
if (t->p_oppid != t->p_pptr->p_pid) {
struct proc *pp;
pp = pfind(t->p_oppid);
proc_reparent(t, pp ? pp : initproc);
}
/* not being traced any more */
t->p_oppid = 0;
CLR(t->p_flag, P_TRACED|P_WAITED);
}
sendsig:
/* Finally, deliver the requested signal (or none). */
if (t->p_stat == SSTOP) {
t->p_xstat = SCARG(uap, data);
SCHED_LOCK(s);
setrunnable(t);
SCHED_UNLOCK(s);
} else {
if (SCARG(uap, data) != 0)
psignal(t, SCARG(uap, data));
}
return (0);
relebad:
PRELE(t);
return (error);
case PT_KILL:
/* just send the process a KILL signal. */
SCARG(uap, data) = SIGKILL;
goto sendsig; /* in PT_CONTINUE, above. */
case PT_ATTACH:
/*
* Go ahead and set the trace flag.
* Save the old parent (it's reset in
* _DETACH, and also in kern_exit.c:wait4()
* Reparent the process so that the tracing
* proc gets to see all the action.
* Stop the target.
*/
SET(t->p_flag, P_TRACED);
t->p_oppid = t->p_pptr->p_pid;
if (t->p_pptr != p)
proc_reparent(t, p);
SCARG(uap, data) = SIGSTOP;
goto sendsig;
#ifdef PT_SETREGS
case PT_SETREGS:
write = 1;
#endif
#ifdef PT_GETREGS
case PT_GETREGS:
/* write = 0 done above. */
#endif
#if defined(PT_SETREGS) || defined(PT_GETREGS)
if (!procfs_validregs(t))
return (EINVAL);
else {
iov.iov_base = SCARG(uap, addr);
iov.iov_len = sizeof(struct reg);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = 0;
uio.uio_resid = sizeof(struct reg);
uio.uio_segflg = UIO_USERSPACE;
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_procp = p;
return (procfs_doregs(p, t, NULL, &uio));
}
#endif
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
write = 1;
#endif
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
/* write = 0 done above. */
#endif
#if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
if (!procfs_validfpregs(t))
return (EINVAL);
else {
iov.iov_base = SCARG(uap, addr);
iov.iov_len = sizeof(struct fpreg);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = 0;
uio.uio_resid = sizeof(struct fpreg);
uio.uio_segflg = UIO_USERSPACE;
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_procp = p;
return (procfs_dofpregs(p, t, NULL, &uio));
}
#endif
}
#ifdef DIAGNOSTIC
panic("ptrace: impossible");
#endif
return 0;
}
int
trace_req(a1)
struct proc *a1;
{
/* just return 1 to keep other parts of the system happy */
return (1);
}
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