2 * Copyright (c) 1993 Jan-Simon Pendry
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
36 * $FreeBSD: src/sys/miscfs/procfs/procfs_ctl.c,v 1.20.2.2 2002/01/22 17:22:59 nectar Exp $
37 * $DragonFly: src/sys/vfs/procfs/procfs_ctl.c,v 1.16 2007/03/12 21:08:15 corecode Exp $
40 #include <sys/param.h>
41 #include <sys/systm.h>
44 #include <sys/vnode.h>
45 #include <sys/ptrace.h>
46 #include <sys/signalvar.h>
47 #include <vfs/procfs/procfs.h>
49 #include <sys/signal2.h>
50 #include <sys/thread2.h>
51 #include <sys/mplock2.h>
52 #include <sys/spinlock2.h>
61 * True iff process (p) is in trace wait state
62 * relative to process (curp)
64 #define TRACE_WAIT_P(curp, p) \
65 (((p)->p_stat == SSTOP) && \
66 (p)->p_pptr == (curp) && \
67 ((p)->p_flags & P_TRACED))
69 #define PROCFS_CTL_ATTACH 1
70 #define PROCFS_CTL_DETACH 2
71 #define PROCFS_CTL_STEP 3
72 #define PROCFS_CTL_RUN 4
73 #define PROCFS_CTL_WAIT 5
75 static vfs_namemap_t ctlnames
[] = {
76 /* special /proc commands */
77 { "attach", PROCFS_CTL_ATTACH
},
78 { "detach", PROCFS_CTL_DETACH
},
79 { "step", PROCFS_CTL_STEP
},
80 { "run", PROCFS_CTL_RUN
},
81 { "wait", PROCFS_CTL_WAIT
},
85 static vfs_namemap_t signames
[] = {
86 /* regular signal names */
87 { "hup", SIGHUP
}, { "int", SIGINT
},
88 { "quit", SIGQUIT
}, { "ill", SIGILL
},
89 { "trap", SIGTRAP
}, { "abrt", SIGABRT
},
90 { "iot", SIGIOT
}, { "emt", SIGEMT
},
91 { "fpe", SIGFPE
}, { "kill", SIGKILL
},
92 { "bus", SIGBUS
}, { "segv", SIGSEGV
},
93 { "sys", SIGSYS
}, { "pipe", SIGPIPE
},
94 { "alrm", SIGALRM
}, { "term", SIGTERM
},
95 { "urg", SIGURG
}, { "stop", SIGSTOP
},
96 { "tstp", SIGTSTP
}, { "cont", SIGCONT
},
97 { "chld", SIGCHLD
}, { "ttin", SIGTTIN
},
98 { "ttou", SIGTTOU
}, { "io", SIGIO
},
99 { "xcpu", SIGXCPU
}, { "xfsz", SIGXFSZ
},
100 { "vtalrm", SIGVTALRM
}, { "prof", SIGPROF
},
101 { "winch", SIGWINCH
}, { "info", SIGINFO
},
102 { "usr1", SIGUSR1
}, { "usr2", SIGUSR2
},
106 static int procfs_control (struct proc
*curp
, struct lwp
*lp
, int op
);
109 procfs_control(struct proc
*curp
, struct lwp
*lp
, int op
)
111 struct proc
*p
= lp
->lwp_proc
;
114 ASSERT_LWKT_TOKEN_HELD(&p
->p_token
);
115 ASSERT_LWKT_TOKEN_HELD(&proc_token
);
117 /* Can't trace a process that's currently exec'ing. */
118 if ((p
->p_flags
& P_INEXEC
) != 0)
121 * Authorization check: rely on normal debugging protection, except
122 * allow processes to disengage debugging on a process onto which
123 * they have previously attached, but no longer have permission to
126 if (op
!= PROCFS_CTL_DETACH
) {
127 if (securelevel
> 0 && p
->p_pid
== 1)
130 if (!CHECKIO(curp
, p
) || p_trespass(curp
->p_ucred
, p
->p_ucred
))
135 * Attach - attaches the target process for debugging
136 * by the calling process.
138 if (op
== PROCFS_CTL_ATTACH
) {
139 /* check whether already being traced */
140 if (p
->p_flags
& P_TRACED
)
143 /* can't trace yourself! */
144 if (p
->p_pid
== curp
->p_pid
)
148 * Go ahead and set the trace flag.
149 * Save the old parent (it's reset in
150 * _DETACH, and also in kern_exit.c:wait4()
151 * Reparent the process so that the tracing
152 * proc gets to see all the action.
155 p
->p_flags
|= P_TRACED
;
157 p
->p_xstat
= 0; /* XXX ? */
158 if (p
->p_pptr
!= curp
) {
159 p
->p_oppid
= p
->p_pptr
->p_pid
;
160 proc_reparent(p
, curp
);
167 * Target process must be stopped, owned by (curp) and
168 * be set up for tracing (P_TRACED flag set).
169 * Allow DETACH to take place at any time for sanity.
170 * Allow WAIT any time, of course.
173 case PROCFS_CTL_DETACH
:
174 case PROCFS_CTL_WAIT
:
178 if (!TRACE_WAIT_P(curp
, p
))
185 * do single-step fixup if needed
191 * Don't deliver any signal by default.
192 * To continue with a signal, just send
193 * the signal name to the ctl file
199 * Detach. Cleans up the target process, reparent it if possible
200 * and set it running once more.
202 case PROCFS_CTL_DETACH
:
203 /* if not being traced, then this is a painless no-op */
204 if ((p
->p_flags
& P_TRACED
) == 0)
207 /* not being traced any more */
208 p
->p_flags
&= ~P_TRACED
;
210 /* remove pending SIGTRAP, else the process will die */
211 spin_lock(&lp
->lwp_spin
);
212 lwp_delsig(lp
, SIGTRAP
);
213 spin_unlock(&lp
->lwp_spin
);
215 /* give process back to original parent */
216 if (p
->p_oppid
!= p
->p_pptr
->p_pid
) {
219 pp
= pfs_pfind(p
->p_oppid
);
221 proc_reparent(p
, pp
);
227 p
->p_flags
&= ~P_WAITED
; /* XXX ? */
228 wakeup((caddr_t
) curp
); /* XXX for CTL_WAIT below ? */
233 * Step. Let the target process execute a single instruction.
235 case PROCFS_CTL_STEP
:
237 error
= procfs_sstep(lp
);
244 * Run. Let the target process continue running until a breakpoint
245 * or some other trap.
251 * Wait for the target process to stop.
252 * If the target is not being traced then just wait
255 case PROCFS_CTL_WAIT
:
257 if (p
->p_flags
& P_TRACED
) {
259 p
->p_stat
!= SSTOP
&&
260 (p
->p_flags
& P_TRACED
) &&
261 (p
->p_pptr
== curp
)) {
262 error
= tsleep((caddr_t
) p
,
263 PCATCH
, "procfsx", 0);
265 if (error
== 0 && !TRACE_WAIT_P(curp
, p
))
268 while (error
== 0 && p
->p_stat
!= SSTOP
) {
269 error
= tsleep((caddr_t
) p
,
270 PCATCH
, "procfs", 0);
276 panic("procfs_control");
280 * If the process is in a stopped state, make it runnable again.
281 * Do not set LWP_MP_BREAKTSLEEP - that is, do not break a tsleep
282 * that might be in progress.
284 if (p
->p_stat
== SSTOP
)
290 procfs_doctl(struct proc
*curp
, struct lwp
*lp
, struct pfsnode
*pfs
,
293 struct proc
*p
= lp
->lwp_proc
;
296 char msg
[PROCFS_CTLLEN
+1];
299 ASSERT_LWKT_TOKEN_HELD(&p
->p_token
);
300 ASSERT_LWKT_TOKEN_HELD(&proc_token
);
302 if (uio
->uio_rw
!= UIO_WRITE
)
305 xlen
= PROCFS_CTLLEN
;
306 error
= vfs_getuserstr(uio
, msg
, &xlen
);
311 * Map signal names into signal generation
312 * or debug control. Unknown commands and/or signals
315 * Sending a signal while the process is being debugged
316 * also has the side effect of letting the target continue
317 * to run. There is no way to single-step a signal delivery.
321 nm
= vfs_findname(ctlnames
, msg
, xlen
);
323 error
= procfs_control(curp
, lp
, nm
->nm_val
);
325 nm
= vfs_findname(signames
, msg
, xlen
);
327 if (TRACE_WAIT_P(curp
, p
)) {
328 p
->p_xstat
= nm
->nm_val
;
333 * Make the process runnable but do not
338 ksignal(p
, nm
->nm_val
);