664f718ba1
race where a thread could assume that a process was swapped in by PHOLD() when it actually wasn't fully swapped in yet. - In faultin(), always msleep() if PS_SWAPPINGIN is set instead of doing this check after bumping p_lock in the PS_INMEM == 0 case. Also, sched_lock is only needed for setting and clearning swapping PS_* flags and the swap thread inhibitor. - Don't set and clear the thread swap inhibitor in the same loops as the pmap_swapin/out_thread() since we have to do it under sched_lock. Instead, mimic the treatment of the PS_INMEM flag and use separate loops to set the inhibitors when clearing PS_INMEM and clear the inhibitors when setting PS_INMEM. - swapout() now returns with the proc lock held as it holds the lock while adjusting the swapping-related PS_* flags so that the proc lock can be used to test those flags. - Only use the proc lock to check the swapping-related PS_* flags in several places. - faultin() no longer requires sched_lock to be held by callers. - Rename PS_SWAPPING to PS_SWAPPINGOUT to be less ambiguous now that we have PS_SWAPPINGIN.
364 lines
9.2 KiB
C
364 lines
9.2 KiB
C
/*
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* Copyright (c) 1993 Jan-Simon Pendry
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry.
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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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* @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
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*
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* From:
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* $Id: procfs_ctl.c,v 3.2 1993/12/15 09:40:17 jsp Exp $
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/ptrace.h>
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#include <sys/sbuf.h>
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#include <sys/signalvar.h>
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#include <sys/sx.h>
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#include <sys/uio.h>
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#include <fs/pseudofs/pseudofs.h>
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#include <fs/procfs/procfs.h>
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#include <vm/vm.h>
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/*
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* True iff process (p) is in trace wait state
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* relative to process (curp)
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*/
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#define TRACE_WAIT_P(curp, p) \
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(P_SHOULDSTOP(p) && \
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(p)->p_pptr == (curp) && \
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((p)->p_flag & P_TRACED))
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#define PROCFS_CTL_ATTACH 1
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#define PROCFS_CTL_DETACH 2
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#define PROCFS_CTL_STEP 3
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#define PROCFS_CTL_RUN 4
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#define PROCFS_CTL_WAIT 5
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struct namemap {
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const char *nm_name;
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int nm_val;
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};
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static struct namemap ctlnames[] = {
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/* special /proc commands */
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{ "attach", PROCFS_CTL_ATTACH },
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{ "detach", PROCFS_CTL_DETACH },
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{ "step", PROCFS_CTL_STEP },
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{ "run", PROCFS_CTL_RUN },
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{ "wait", PROCFS_CTL_WAIT },
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{ 0 },
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};
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static struct namemap signames[] = {
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/* regular signal names */
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{ "hup", SIGHUP }, { "int", SIGINT },
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{ "quit", SIGQUIT }, { "ill", SIGILL },
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{ "trap", SIGTRAP }, { "abrt", SIGABRT },
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{ "iot", SIGIOT }, { "emt", SIGEMT },
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{ "fpe", SIGFPE }, { "kill", SIGKILL },
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{ "bus", SIGBUS }, { "segv", SIGSEGV },
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{ "sys", SIGSYS }, { "pipe", SIGPIPE },
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{ "alrm", SIGALRM }, { "term", SIGTERM },
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{ "urg", SIGURG }, { "stop", SIGSTOP },
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{ "tstp", SIGTSTP }, { "cont", SIGCONT },
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{ "chld", SIGCHLD }, { "ttin", SIGTTIN },
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{ "ttou", SIGTTOU }, { "io", SIGIO },
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{ "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
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{ "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
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{ "winch", SIGWINCH }, { "info", SIGINFO },
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{ "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
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{ 0 },
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};
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static int procfs_control(struct thread *td, struct proc *p, int op);
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static int
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procfs_control(struct thread *td, struct proc *p, int op)
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{
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int error = 0;
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/*
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* Attach - attaches the target process for debugging
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* by the calling process.
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*/
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if (op == PROCFS_CTL_ATTACH) {
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sx_xlock(&proctree_lock);
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PROC_LOCK(p);
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if ((error = p_candebug(td, p)) != 0)
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goto out;
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if (p->p_flag & P_TRACED) {
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error = EBUSY;
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goto out;
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}
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/* Can't trace yourself! */
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if (p->p_pid == td->td_proc->p_pid) {
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error = EINVAL;
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goto out;
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}
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/*
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* Go ahead and set the trace flag.
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* Save the old parent (it's reset in
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* _DETACH, and also in kern_exit.c:wait4()
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* Reparent the process so that the tracing
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* proc gets to see all the action.
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* Stop the target.
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*/
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p->p_flag |= P_TRACED;
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faultin(p);
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p->p_xstat = 0; /* XXX ? */
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if (p->p_pptr != td->td_proc) {
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p->p_oppid = p->p_pptr->p_pid;
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proc_reparent(p, td->td_proc);
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}
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psignal(p, SIGSTOP);
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out:
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PROC_UNLOCK(p);
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sx_xunlock(&proctree_lock);
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return (error);
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}
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/*
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* Authorization check: rely on normal debugging protection, except
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* allow processes to disengage debugging on a process onto which
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* they have previously attached, but no longer have permission to
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* debug.
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*/
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PROC_LOCK(p);
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if (op != PROCFS_CTL_DETACH &&
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((error = p_candebug(td, p)))) {
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PROC_UNLOCK(p);
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return (error);
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}
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/*
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* Target process must be stopped, owned by (td) and
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* be set up for tracing (P_TRACED flag set).
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* Allow DETACH to take place at any time for sanity.
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* Allow WAIT any time, of course.
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*/
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switch (op) {
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case PROCFS_CTL_DETACH:
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case PROCFS_CTL_WAIT:
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break;
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default:
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if (!TRACE_WAIT_P(td->td_proc, p)) {
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PROC_UNLOCK(p);
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return (EBUSY);
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}
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}
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#ifdef FIX_SSTEP
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/*
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* do single-step fixup if needed
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*/
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FIX_SSTEP(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
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#endif
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/*
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* Don't deliver any signal by default.
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* To continue with a signal, just send
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* the signal name to the ctl file
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*/
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p->p_xstat = 0;
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switch (op) {
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/*
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* Detach. Cleans up the target process, reparent it if possible
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* and set it running once more.
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*/
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case PROCFS_CTL_DETACH:
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/* if not being traced, then this is a painless no-op */
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if ((p->p_flag & P_TRACED) == 0) {
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PROC_UNLOCK(p);
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return (0);
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}
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/* not being traced any more */
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p->p_flag &= ~P_TRACED;
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/* remove pending SIGTRAP, else the process will die */
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SIGDELSET(p->p_siglist, SIGTRAP);
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PROC_UNLOCK(p);
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/* give process back to original parent */
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sx_xlock(&proctree_lock);
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if (p->p_oppid != p->p_pptr->p_pid) {
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struct proc *pp;
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pp = pfind(p->p_oppid);
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PROC_LOCK(p);
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if (pp) {
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PROC_UNLOCK(pp);
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proc_reparent(p, pp);
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}
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} else
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PROC_LOCK(p);
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p->p_oppid = 0;
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p->p_flag &= ~P_WAITED; /* XXX ? */
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PROC_UNLOCK(p);
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sx_xunlock(&proctree_lock);
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wakeup(td->td_proc); /* XXX for CTL_WAIT below ? */
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break;
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/*
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* Step. Let the target process execute a single instruction.
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* What does it mean to single step a threaded program?
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*/
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case PROCFS_CTL_STEP:
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PROC_UNLOCK(p);
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error = proc_sstep(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
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PRELE(p);
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if (error)
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return (error);
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break;
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/*
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* Run. Let the target process continue running until a breakpoint
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* or some other trap.
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*/
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case PROCFS_CTL_RUN:
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p->p_flag &= ~P_STOPPED_SIG; /* this uses SIGSTOP */
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PROC_UNLOCK(p);
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break;
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/*
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* Wait for the target process to stop.
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* If the target is not being traced then just wait
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* to enter
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*/
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case PROCFS_CTL_WAIT:
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if (p->p_flag & P_TRACED) {
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while (error == 0 &&
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(P_SHOULDSTOP(p)) &&
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(p->p_flag & P_TRACED) &&
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(p->p_pptr == td->td_proc))
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error = msleep(p, &p->p_mtx,
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PWAIT|PCATCH, "procfsx", 0);
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if (error == 0 && !TRACE_WAIT_P(td->td_proc, p))
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error = EBUSY;
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} else {
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while (error == 0 && P_SHOULDSTOP(p))
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error = msleep(p, &p->p_mtx,
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PWAIT|PCATCH, "procfs", 0);
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}
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PROC_UNLOCK(p);
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return (error);
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default:
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panic("procfs_control");
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}
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mtx_lock_spin(&sched_lock);
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thread_unsuspend(p); /* If it can run, let it do so. */
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mtx_unlock_spin(&sched_lock);
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return (0);
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}
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static struct namemap *
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findname(struct namemap *nm, char *buf, int buflen)
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{
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for (; nm->nm_name; nm++)
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if (bcmp(buf, nm->nm_name, buflen+1) == 0)
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return (nm);
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return (0);
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}
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int
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procfs_doprocctl(PFS_FILL_ARGS)
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{
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int error;
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struct namemap *nm;
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if (uio == NULL || uio->uio_rw != UIO_WRITE)
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return (EOPNOTSUPP);
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/*
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* Map signal names into signal generation
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* or debug control. Unknown commands and/or signals
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* return EOPNOTSUPP.
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*
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* Sending a signal while the process is being debugged
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* also has the side effect of letting the target continue
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* to run. There is no way to single-step a signal delivery.
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*/
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error = EOPNOTSUPP;
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sbuf_trim(sb);
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sbuf_finish(sb);
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nm = findname(ctlnames, sbuf_data(sb), sbuf_len(sb));
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if (nm) {
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printf("procfs: got a %s command\n", sbuf_data(sb));
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error = procfs_control(td, p, nm->nm_val);
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} else {
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nm = findname(signames, sbuf_data(sb), sbuf_len(sb));
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if (nm) {
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printf("procfs: got a sig%s\n", sbuf_data(sb));
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PROC_LOCK(p);
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/* This is very broken XXXKSE: */
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if (TRACE_WAIT_P(td->td_proc, p)) {
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p->p_xstat = nm->nm_val;
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#ifdef FIX_SSTEP
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/* XXXKSE: */
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FIX_SSTEP(FIRST_THREAD_IN_PROC(p));
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#endif
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/* XXXKSE: */
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p->p_flag &= ~P_STOPPED_SIG;
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mtx_lock_spin(&sched_lock);
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thread_unsuspend(p);
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mtx_unlock_spin(&sched_lock);
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} else
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psignal(p, nm->nm_val);
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PROC_UNLOCK(p);
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error = 0;
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}
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}
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return (error);
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}
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