1 /*-
2 * Copyright (c) 1993 Jan-Simon Pendry
3 * Copyright (c) 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Jan-Simon Pendry.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
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.
20 *
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
31 * SUCH DAMAGE.
32 *
33 * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
34 *
35 * From:
36 * $Id: procfs_ctl.c,v 1.51 2003/12/07 17:40:00 des Exp $
37 * $FreeBSD: stable/10/sys/fs/procfs/procfs_ctl.c 287604 2015-09-09 23:39:30Z jhb $
38 */
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/lock.h>
43 #include <sys/mutex.h>
44 #include <sys/proc.h>
45 #include <sys/ptrace.h>
46 #include <sys/sbuf.h>
47 #include <sys/signalvar.h>
48 #include <sys/sx.h>
49 #include <sys/uio.h>
50
51 #include <fs/pseudofs/pseudofs.h>
52 #include <fs/procfs/procfs.h>
53
54 #include <vm/vm.h>
55
56 /*
57 * True iff process (p) is in trace wait state
58 * relative to process (curp)
59 */
60 #define TRACE_WAIT_P(curp, p) \
61 (P_SHOULDSTOP(p) && \
62 (p)->p_pptr == (curp) && \
63 ((p)->p_flag & P_TRACED))
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 struct namemap {
72 const char *nm_name;
73 int nm_val;
74 };
75
76 static struct namemap ctlnames[] = {
77 /* special /proc commands */
78 { "attach", PROCFS_CTL_ATTACH },
79 { "detach", PROCFS_CTL_DETACH },
80 { "step", PROCFS_CTL_STEP },
81 { "run", PROCFS_CTL_RUN },
82 { "wait", PROCFS_CTL_WAIT },
83 { 0 },
84 };
85
86 static struct namemap signames[] = {
87 /* regular signal names */
88 { "hup", SIGHUP }, { "int", SIGINT },
89 { "quit", SIGQUIT }, { "ill", SIGILL },
90 { "trap", SIGTRAP }, { "abrt", SIGABRT },
91 { "iot", SIGIOT }, { "emt", SIGEMT },
92 { "fpe", SIGFPE }, { "kill", SIGKILL },
93 { "bus", SIGBUS }, { "segv", SIGSEGV },
94 { "sys", SIGSYS }, { "pipe", SIGPIPE },
95 { "alrm", SIGALRM }, { "term", SIGTERM },
96 { "urg", SIGURG }, { "stop", SIGSTOP },
97 { "tstp", SIGTSTP }, { "cont", SIGCONT },
98 { "chld", SIGCHLD }, { "ttin", SIGTTIN },
99 { "ttou", SIGTTOU }, { "io", SIGIO },
100 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
101 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
102 { "winch", SIGWINCH }, { "info", SIGINFO },
103 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
104 { 0 },
105 };
106
107 static int procfs_control(struct thread *td, struct proc *p, int op);
108
109 static int
procfs_control(struct thread * td,struct proc * p,int op)110 procfs_control(struct thread *td, struct proc *p, int op)
111 {
112 int error = 0;
113 struct thread *temp;
114
115 /*
116 * Attach - attaches the target process for debugging
117 * by the calling process.
118 */
119 if (op == PROCFS_CTL_ATTACH) {
120 sx_xlock(&proctree_lock);
121 PROC_LOCK(p);
122 if ((error = p_candebug(td, p)) != 0)
123 goto out;
124 if (p->p_flag & P_TRACED) {
125 error = EBUSY;
126 goto out;
127 }
128
129 /* Can't trace yourself! */
130 if (p->p_pid == td->td_proc->p_pid) {
131 error = EINVAL;
132 goto out;
133 }
134
135 /*
136 * Go ahead and set the trace flag.
137 * Save the old parent (it's reset in
138 * _DETACH, and also in kern_exit.c:wait4()
139 * Reparent the process so that the tracing
140 * proc gets to see all the action.
141 * Stop the target.
142 */
143 p->p_flag |= P_TRACED;
144 faultin(p);
145 p->p_xstat = 0; /* XXX ? */
146 p->p_oppid = p->p_pptr->p_pid;
147 if (p->p_pptr != td->td_proc) {
148 proc_reparent(p, td->td_proc);
149 }
150 kern_psignal(p, SIGSTOP);
151 out:
152 PROC_UNLOCK(p);
153 sx_xunlock(&proctree_lock);
154 return (error);
155 }
156
157 /*
158 * Authorization check: rely on normal debugging protection, except
159 * allow processes to disengage debugging on a process onto which
160 * they have previously attached, but no longer have permission to
161 * debug.
162 */
163 PROC_LOCK(p);
164 if (op != PROCFS_CTL_DETACH &&
165 ((error = p_candebug(td, p)))) {
166 PROC_UNLOCK(p);
167 return (error);
168 }
169
170 /*
171 * Target process must be stopped, owned by (td) and
172 * be set up for tracing (P_TRACED flag set).
173 * Allow DETACH to take place at any time for sanity.
174 * Allow WAIT any time, of course.
175 */
176 switch (op) {
177 case PROCFS_CTL_DETACH:
178 case PROCFS_CTL_WAIT:
179 break;
180
181 default:
182 if (!TRACE_WAIT_P(td->td_proc, p)) {
183 PROC_UNLOCK(p);
184 return (EBUSY);
185 }
186 }
187
188
189 #ifdef FIX_SSTEP
190 /*
191 * do single-step fixup if needed
192 */
193 FIX_SSTEP(FIRST_THREAD_IN_PROC(p));
194 #endif
195
196 /*
197 * Don't deliver any signal by default.
198 * To continue with a signal, just send
199 * the signal name to the ctl file
200 */
201 p->p_xstat = 0;
202
203 switch (op) {
204 /*
205 * Detach. Cleans up the target process, reparent it if possible
206 * and set it running once more.
207 */
208 case PROCFS_CTL_DETACH:
209 /* if not being traced, then this is a painless no-op */
210 if ((p->p_flag & P_TRACED) == 0) {
211 PROC_UNLOCK(p);
212 return (0);
213 }
214
215 /* not being traced any more */
216 p->p_flag &= ~(P_TRACED | P_STOPPED_TRACE);
217
218 /* remove pending SIGTRAP, else the process will die */
219 sigqueue_delete_proc(p, SIGTRAP);
220 FOREACH_THREAD_IN_PROC(p, temp)
221 temp->td_dbgflags &= ~TDB_SUSPEND;
222 PROC_UNLOCK(p);
223
224 /* give process back to original parent */
225 sx_xlock(&proctree_lock);
226 if (p->p_oppid != p->p_pptr->p_pid) {
227 struct proc *pp;
228
229 pp = pfind(p->p_oppid);
230 PROC_LOCK(p);
231 if (pp) {
232 PROC_UNLOCK(pp);
233 proc_reparent(p, pp);
234 }
235 } else
236 PROC_LOCK(p);
237 p->p_oppid = 0;
238 p->p_stops = 0;
239 p->p_flag &= ~P_WAITED; /* XXX ? */
240 sx_xunlock(&proctree_lock);
241
242 wakeup(td->td_proc); /* XXX for CTL_WAIT below ? */
243
244 break;
245
246 /*
247 * Step. Let the target process execute a single instruction.
248 * What does it mean to single step a threaded program?
249 */
250 case PROCFS_CTL_STEP:
251 error = proc_sstep(FIRST_THREAD_IN_PROC(p));
252 if (error) {
253 PROC_UNLOCK(p);
254 return (error);
255 }
256 break;
257
258 /*
259 * Run. Let the target process continue running until a breakpoint
260 * or some other trap.
261 */
262 case PROCFS_CTL_RUN:
263 p->p_flag &= ~P_STOPPED_SIG; /* this uses SIGSTOP */
264 break;
265
266 /*
267 * Wait for the target process to stop.
268 * If the target is not being traced then just wait
269 * to enter
270 */
271 case PROCFS_CTL_WAIT:
272 if (p->p_flag & P_TRACED) {
273 while (error == 0 &&
274 (P_SHOULDSTOP(p)) &&
275 (p->p_flag & P_TRACED) &&
276 (p->p_pptr == td->td_proc))
277 error = msleep(p, &p->p_mtx,
278 PWAIT|PCATCH, "procfsx", 0);
279 if (error == 0 && !TRACE_WAIT_P(td->td_proc, p))
280 error = EBUSY;
281 } else {
282 while (error == 0 && P_SHOULDSTOP(p))
283 error = msleep(p, &p->p_mtx,
284 PWAIT|PCATCH, "procfs", 0);
285 }
286 PROC_UNLOCK(p);
287 return (error);
288 default:
289 panic("procfs_control");
290 }
291
292 PROC_SLOCK(p);
293 thread_unsuspend(p); /* If it can run, let it do so. */
294 PROC_SUNLOCK(p);
295 PROC_UNLOCK(p);
296 return (0);
297 }
298
299 static struct namemap *
findname(struct namemap * nm,char * buf,int buflen)300 findname(struct namemap *nm, char *buf, int buflen)
301 {
302
303 for (; nm->nm_name; nm++)
304 if (bcmp(buf, nm->nm_name, buflen+1) == 0)
305 return (nm);
306
307 return (0);
308 }
309
310 int
procfs_doprocctl(PFS_FILL_ARGS)311 procfs_doprocctl(PFS_FILL_ARGS)
312 {
313 int error;
314 struct namemap *nm;
315
316 if (uio == NULL || uio->uio_rw != UIO_WRITE)
317 return (EOPNOTSUPP);
318
319 /*
320 * Map signal names into signal generation
321 * or debug control. Unknown commands and/or signals
322 * return EOPNOTSUPP.
323 *
324 * Sending a signal while the process is being debugged
325 * also has the side effect of letting the target continue
326 * to run. There is no way to single-step a signal delivery.
327 */
328 error = EOPNOTSUPP;
329
330 sbuf_trim(sb);
331 sbuf_finish(sb);
332 nm = findname(ctlnames, sbuf_data(sb), sbuf_len(sb));
333 if (nm) {
334 printf("procfs: got a %s command\n", sbuf_data(sb));
335 error = procfs_control(td, p, nm->nm_val);
336 } else {
337 nm = findname(signames, sbuf_data(sb), sbuf_len(sb));
338 if (nm) {
339 printf("procfs: got a sig%s\n", sbuf_data(sb));
340 PROC_LOCK(p);
341
342 if (TRACE_WAIT_P(td->td_proc, p)) {
343 p->p_xstat = nm->nm_val;
344 #ifdef FIX_SSTEP
345 FIX_SSTEP(FIRST_THREAD_IN_PROC(p));
346 #endif
347 p->p_flag &= ~P_STOPPED_SIG;
348 PROC_SLOCK(p);
349 thread_unsuspend(p);
350 PROC_SUNLOCK(p);
351 } else
352 kern_psignal(p, nm->nm_val);
353 PROC_UNLOCK(p);
354 error = 0;
355 }
356 }
357
358 return (error);
359 }
360