1 /* $OpenBSD: procfs_ctl.c,v 1.21 2007/06/18 08:30:07 jasper Exp $ */
2 /* $NetBSD: procfs_ctl.c,v 1.14 1996/02/09 22:40:48 christos Exp $ */
3
4 /*
5 * Copyright (c) 1993 Jan-Simon Pendry
6 * Copyright (c) 1993
7 * The Regents of the University of California. All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * Jan-Simon Pendry.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
37 */
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/time.h>
42 #include <sys/kernel.h>
43 #include <sys/proc.h>
44 #include <sys/vnode.h>
45 #include <sys/ioctl.h>
46 #include <sys/tty.h>
47 #include <sys/resource.h>
48 #include <sys/resourcevar.h>
49 #include <sys/signalvar.h>
50 #include <sys/ptrace.h>
51 #include <sys/sched.h>
52 #include <miscfs/procfs/procfs.h>
53
54 /*
55 * True iff process (p) is in trace wait state
56 * relative to process (curp)
57 */
58 #define TRACE_WAIT_P(curp, p) \
59 ((p)->p_stat == SSTOP && \
60 (p)->p_pptr == (curp) && \
61 ISSET((p)->p_flag, P_TRACED))
62
63 #ifdef PTRACE
64
65 #define PROCFS_CTL_ATTACH 1
66 #define PROCFS_CTL_DETACH 2
67 #define PROCFS_CTL_STEP 3
68 #define PROCFS_CTL_RUN 4
69 #define PROCFS_CTL_WAIT 5
70
71 static const vfs_namemap_t ctlnames[] = {
72 /* special /proc commands */
73 { "attach", PROCFS_CTL_ATTACH },
74 { "detach", PROCFS_CTL_DETACH },
75 { "step", PROCFS_CTL_STEP },
76 { "run", PROCFS_CTL_RUN },
77 { "wait", PROCFS_CTL_WAIT },
78 { 0 },
79 };
80
81 #endif
82
83 static const vfs_namemap_t signames[] = {
84 /* regular signal names */
85 { "hup", SIGHUP }, { "int", SIGINT },
86 { "quit", SIGQUIT }, { "ill", SIGILL },
87 { "trap", SIGTRAP }, { "abrt", SIGABRT },
88 { "iot", SIGIOT }, { "emt", SIGEMT },
89 { "fpe", SIGFPE }, { "kill", SIGKILL },
90 { "bus", SIGBUS }, { "segv", SIGSEGV },
91 { "sys", SIGSYS }, { "pipe", SIGPIPE },
92 { "alrm", SIGALRM }, { "term", SIGTERM },
93 { "urg", SIGURG }, { "stop", SIGSTOP },
94 { "tstp", SIGTSTP }, { "cont", SIGCONT },
95 { "chld", SIGCHLD }, { "ttin", SIGTTIN },
96 { "ttou", SIGTTOU }, { "io", SIGIO },
97 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
98 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
99 { "winch", SIGWINCH }, { "info", SIGINFO },
100 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
101 { 0 },
102 };
103
104 #ifdef PTRACE
105 static int procfs_control(struct proc *, struct proc *, int);
106
107 static int
108 procfs_control(struct proc *curp, struct proc *p, int op)
109 /* *curp being the tracer, and *p the traced */
110 {
111 int error;
112 int s;
113
114 /*
115 * Attach - attaches the target process for debugging
116 * by the calling process.
117 */
118 if (op == PROCFS_CTL_ATTACH) {
119 /* Can't trace yourself! */
120 if (p->p_pid == curp->p_pid)
121 return (EINVAL);
122
123 /* Check whether already being traced. */
124 if (ISSET(p->p_flag, P_TRACED))
125 return (EBUSY);
126
127 if ((error = process_checkioperm(curp, p)) != 0)
128 return (error);
129
130 /*
131 * Go ahead and set the trace flag.
132 * Save the old parent (it's reset in
133 * _DETACH, and also in kern_exit.c:wait4()
134 * Reparent the process so that the tracing
135 * proc gets to see all the action.
136 * Stop the target.
137 */
138 atomic_setbits_int(&p->p_flag, P_TRACED);
139 p->p_xstat = 0; /* XXX ? */
140 if (p->p_pptr != curp) {
141 p->p_oppid = p->p_pptr->p_pid;
142 proc_reparent(p, curp);
143 }
144 psignal(p, SIGSTOP);
145 return (0);
146 }
147
148 /*
149 * Target process must be stopped, owned by (curp) and
150 * be set up for tracing (P_TRACED flag set).
151 * Allow DETACH to take place at any time for sanity.
152 * Allow WAIT any time, of course.
153 */
154 switch (op) {
155 case PROCFS_CTL_DETACH:
156 case PROCFS_CTL_WAIT:
157 break;
158
159 default:
160 if (!TRACE_WAIT_P(curp, p))
161 return (EBUSY);
162 }
163
164 /*
165 * do single-step fixup if needed
166 */
167 FIX_SSTEP(p);
168
169 /*
170 * Don't deliver any signal by default.
171 * To continue with a signal, just send
172 * the signal name to the ctl file
173 */
174 p->p_xstat = 0;
175
176 switch (op) {
177 /*
178 * Detach. Cleans up the target process, reparent it if possible
179 * and set it running once more.
180 */
181 case PROCFS_CTL_DETACH:
182 /* if not being traced, then this is a painless no-op */
183 if (!ISSET(p->p_flag, P_TRACED))
184 return (0);
185
186 /* not being traced any more */
187 atomic_clearbits_int(&p->p_flag, P_TRACED);
188
189 /* give process back to original parent */
190 if (p->p_oppid != p->p_pptr->p_pid) {
191 struct proc *pp;
192
193 pp = pfind(p->p_oppid);
194 if (pp)
195 proc_reparent(p, pp);
196 }
197
198 p->p_oppid = 0;
199 atomic_clearbits_int(&p->p_flag, P_WAITED);
200 wakeup(curp); /* XXX for CTL_WAIT below ? */
201
202 break;
203
204 /*
205 * Step. Let the target process execute a single instruction.
206 */
207 case PROCFS_CTL_STEP:
208 #ifdef PT_STEP
209 error = process_sstep(p, 1);
210 if (error)
211 return (error);
212 break;
213 #else
214 return (EOPNOTSUPP);
215 #endif
216
217 /*
218 * Run. Let the target process continue running until a breakpoint
219 * or some other trap.
220 */
221 case PROCFS_CTL_RUN:
222 break;
223
224 /*
225 * Wait for the target process to stop.
226 * If the target is not being traced then just wait
227 * to enter
228 */
229 case PROCFS_CTL_WAIT:
230 error = 0;
231 if (ISSET(p->p_flag, P_TRACED)) {
232 while (error == 0 &&
233 (p->p_stat != SSTOP) &&
234 ISSET(p->p_flag, P_TRACED) &&
235 (p->p_pptr == curp)) {
236 error = tsleep(p, PWAIT|PCATCH, "procfsx", 0);
237 }
238 if (error == 0 && !TRACE_WAIT_P(curp, p))
239 error = EBUSY;
240 } else {
241 while (error == 0 && p->p_stat != SSTOP) {
242 error = tsleep(p, PWAIT|PCATCH, "procfs", 0);
243 }
244 }
245 return (error);
246
247 #ifdef DIAGNOSTIC
248 default:
249 panic("procfs_control");
250 #endif
251 }
252
253 SCHED_LOCK(s);
254 if (p->p_stat == SSTOP)
255 setrunnable(p);
256 SCHED_UNLOCK(s);
257 return (0);
258 }
259 #endif
260
261 int
262 procfs_doctl(struct proc *curp, struct proc *p, struct pfsnode *pfs, struct uio *uio)
263 {
264 int xlen;
265 int error;
266 char msg[PROCFS_CTLLEN+1];
267 const vfs_namemap_t *nm;
268 int s;
269
270 if (uio->uio_rw != UIO_WRITE)
271 return (EOPNOTSUPP);
272
273 xlen = PROCFS_CTLLEN;
274 error = vfs_getuserstr(uio, msg, &xlen);
275 if (error)
276 return (error);
277
278 /*
279 * Map signal names into signal generation
280 * or debug control. Unknown commands and/or signals
281 * return EOPNOTSUPP.
282 *
283 * Sending a signal while the process is being debugged
284 * also has the side effect of letting the target continue
285 * to run. There is no way to single-step a signal delivery.
286 */
287 error = EOPNOTSUPP;
288
289 #ifdef PTRACE
290 nm = vfs_findname(ctlnames, msg, xlen);
291 if (nm) {
292 error = procfs_control(curp, p, nm->nm_val);
293 } else
294 #endif
295 {
296 nm = vfs_findname(signames, msg, xlen);
297 if (nm) {
298 if (TRACE_WAIT_P(curp, p)) {
299 p->p_xstat = nm->nm_val;
300 FIX_SSTEP(p);
301 SCHED_LOCK(s);
302 setrunnable(p);
303 SCHED_UNLOCK(s);
304 } else {
305 psignal(p, nm->nm_val);
306 }
307 error = 0;
308 }
309 }
310
311 return (error);
312 }