FreeBSD-5.3/sys/fs/procfs/procfs_ctl.c
/*
* Copyright (c) 1993 Jan-Simon Pendry
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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.
* 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.
*
* @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
*
* From:
* $Id: procfs_ctl.c,v 1.51 2003/12/07 17:40:00 des Exp $
* $FreeBSD: src/sys/fs/procfs/procfs_ctl.c,v 1.52 2004/04/07 20:46:02 imp Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/sbuf.h>
#include <sys/signalvar.h>
#include <sys/sx.h>
#include <sys/uio.h>
#include <fs/pseudofs/pseudofs.h>
#include <fs/procfs/procfs.h>
#include <vm/vm.h>
/*
* True iff process (p) is in trace wait state
* relative to process (curp)
*/
#define TRACE_WAIT_P(curp, p) \
(P_SHOULDSTOP(p) && \
(p)->p_pptr == (curp) && \
((p)->p_flag & P_TRACED))
#define PROCFS_CTL_ATTACH 1
#define PROCFS_CTL_DETACH 2
#define PROCFS_CTL_STEP 3
#define PROCFS_CTL_RUN 4
#define PROCFS_CTL_WAIT 5
struct namemap {
const char *nm_name;
int nm_val;
};
static struct namemap ctlnames[] = {
/* special /proc commands */
{ "attach", PROCFS_CTL_ATTACH },
{ "detach", PROCFS_CTL_DETACH },
{ "step", PROCFS_CTL_STEP },
{ "run", PROCFS_CTL_RUN },
{ "wait", PROCFS_CTL_WAIT },
{ 0 },
};
static struct namemap signames[] = {
/* regular signal names */
{ "hup", SIGHUP }, { "int", SIGINT },
{ "quit", SIGQUIT }, { "ill", SIGILL },
{ "trap", SIGTRAP }, { "abrt", SIGABRT },
{ "iot", SIGIOT }, { "emt", SIGEMT },
{ "fpe", SIGFPE }, { "kill", SIGKILL },
{ "bus", SIGBUS }, { "segv", SIGSEGV },
{ "sys", SIGSYS }, { "pipe", SIGPIPE },
{ "alrm", SIGALRM }, { "term", SIGTERM },
{ "urg", SIGURG }, { "stop", SIGSTOP },
{ "tstp", SIGTSTP }, { "cont", SIGCONT },
{ "chld", SIGCHLD }, { "ttin", SIGTTIN },
{ "ttou", SIGTTOU }, { "io", SIGIO },
{ "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
{ "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
{ "winch", SIGWINCH }, { "info", SIGINFO },
{ "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
{ 0 },
};
static int procfs_control(struct thread *td, struct proc *p, int op);
static int
procfs_control(struct thread *td, struct proc *p, int op)
{
int error = 0;
/*
* Attach - attaches the target process for debugging
* by the calling process.
*/
if (op == PROCFS_CTL_ATTACH) {
sx_xlock(&proctree_lock);
PROC_LOCK(p);
if ((error = p_candebug(td, p)) != 0)
goto out;
if (p->p_flag & P_TRACED) {
error = EBUSY;
goto out;
}
/* Can't trace yourself! */
if (p->p_pid == td->td_proc->p_pid) {
error = EINVAL;
goto out;
}
/*
* 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.
*/
p->p_flag |= P_TRACED;
faultin(p);
p->p_xstat = 0; /* XXX ? */
if (p->p_pptr != td->td_proc) {
p->p_oppid = p->p_pptr->p_pid;
proc_reparent(p, td->td_proc);
}
psignal(p, SIGSTOP);
out:
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
return (error);
}
/*
* Authorization check: rely on normal debugging protection, except
* allow processes to disengage debugging on a process onto which
* they have previously attached, but no longer have permission to
* debug.
*/
PROC_LOCK(p);
if (op != PROCFS_CTL_DETACH &&
((error = p_candebug(td, p)))) {
PROC_UNLOCK(p);
return (error);
}
/*
* Target process must be stopped, owned by (td) and
* be set up for tracing (P_TRACED flag set).
* Allow DETACH to take place at any time for sanity.
* Allow WAIT any time, of course.
*/
switch (op) {
case PROCFS_CTL_DETACH:
case PROCFS_CTL_WAIT:
break;
default:
if (!TRACE_WAIT_P(td->td_proc, p)) {
PROC_UNLOCK(p);
return (EBUSY);
}
}
#ifdef FIX_SSTEP
/*
* do single-step fixup if needed
*/
FIX_SSTEP(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
#endif
/*
* Don't deliver any signal by default.
* To continue with a signal, just send
* the signal name to the ctl file
*/
p->p_xstat = 0;
switch (op) {
/*
* Detach. Cleans up the target process, reparent it if possible
* and set it running once more.
*/
case PROCFS_CTL_DETACH:
/* if not being traced, then this is a painless no-op */
if ((p->p_flag & P_TRACED) == 0) {
PROC_UNLOCK(p);
return (0);
}
/* not being traced any more */
p->p_flag &= ~P_TRACED;
/* remove pending SIGTRAP, else the process will die */
SIGDELSET(p->p_siglist, SIGTRAP);
PROC_UNLOCK(p);
/* give process back to original parent */
sx_xlock(&proctree_lock);
if (p->p_oppid != p->p_pptr->p_pid) {
struct proc *pp;
pp = pfind(p->p_oppid);
PROC_LOCK(p);
if (pp) {
PROC_UNLOCK(pp);
proc_reparent(p, pp);
}
} else
PROC_LOCK(p);
p->p_oppid = 0;
p->p_flag &= ~P_WAITED; /* XXX ? */
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
wakeup(td->td_proc); /* XXX for CTL_WAIT below ? */
break;
/*
* Step. Let the target process execute a single instruction.
* What does it mean to single step a threaded program?
*/
case PROCFS_CTL_STEP:
PROC_UNLOCK(p);
error = proc_sstep(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
PRELE(p);
if (error)
return (error);
break;
/*
* Run. Let the target process continue running until a breakpoint
* or some other trap.
*/
case PROCFS_CTL_RUN:
p->p_flag &= ~P_STOPPED_SIG; /* this uses SIGSTOP */
PROC_UNLOCK(p);
break;
/*
* Wait for the target process to stop.
* If the target is not being traced then just wait
* to enter
*/
case PROCFS_CTL_WAIT:
if (p->p_flag & P_TRACED) {
while (error == 0 &&
(P_SHOULDSTOP(p)) &&
(p->p_flag & P_TRACED) &&
(p->p_pptr == td->td_proc))
error = msleep(p, &p->p_mtx,
PWAIT|PCATCH, "procfsx", 0);
if (error == 0 && !TRACE_WAIT_P(td->td_proc, p))
error = EBUSY;
} else {
while (error == 0 && P_SHOULDSTOP(p))
error = msleep(p, &p->p_mtx,
PWAIT|PCATCH, "procfs", 0);
}
PROC_UNLOCK(p);
return (error);
default:
panic("procfs_control");
}
mtx_lock_spin(&sched_lock);
thread_unsuspend(p); /* If it can run, let it do so. */
mtx_unlock_spin(&sched_lock);
return (0);
}
static struct namemap *
findname(struct namemap *nm, char *buf, int buflen)
{
for (; nm->nm_name; nm++)
if (bcmp(buf, nm->nm_name, buflen+1) == 0)
return (nm);
return (0);
}
int
procfs_doprocctl(PFS_FILL_ARGS)
{
int error;
struct namemap *nm;
if (uio == NULL || uio->uio_rw != UIO_WRITE)
return (EOPNOTSUPP);
/*
* Map signal names into signal generation
* or debug control. Unknown commands and/or signals
* return EOPNOTSUPP.
*
* Sending a signal while the process is being debugged
* also has the side effect of letting the target continue
* to run. There is no way to single-step a signal delivery.
*/
error = EOPNOTSUPP;
sbuf_trim(sb);
sbuf_finish(sb);
nm = findname(ctlnames, sbuf_data(sb), sbuf_len(sb));
if (nm) {
printf("procfs: got a %s command\n", sbuf_data(sb));
error = procfs_control(td, p, nm->nm_val);
} else {
nm = findname(signames, sbuf_data(sb), sbuf_len(sb));
if (nm) {
printf("procfs: got a sig%s\n", sbuf_data(sb));
PROC_LOCK(p);
/* This is very broken XXXKSE: */
if (TRACE_WAIT_P(td->td_proc, p)) {
p->p_xstat = nm->nm_val;
#ifdef FIX_SSTEP
/* XXXKSE: */
FIX_SSTEP(FIRST_THREAD_IN_PROC(p));
#endif
/* XXXKSE: */
p->p_flag &= ~P_STOPPED_SIG;
mtx_lock_spin(&sched_lock);
thread_unsuspend(p);
mtx_unlock_spin(&sched_lock);
} else
psignal(p, nm->nm_val);
PROC_UNLOCK(p);
error = 0;
}
}
return (error);
}