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 * $FreeBSD$
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
110 procfs_control(struct thread *td, struct proc *p, int op)
111 {
112 int error = 0;
113
114 /*
115 * Attach - attaches the target process for debugging
116 * by the calling process.
117 */
118 if (op == PROCFS_CTL_ATTACH) {
119 sx_xlock(&proctree_lock);
120 PROC_LOCK(p);
121 if ((error = p_candebug(td, p)) != 0)
122 goto out;
123 if (p->p_flag & P_TRACED) {
124 error = EBUSY;
125 goto out;
126 }
127
128 /* Can't trace yourself! */
129 if (p->p_pid == td->td_proc->p_pid) {
130 error = EINVAL;
131 goto out;
132 }
133
134 /*
135 * Go ahead and set the trace flag.
136 * Save the old parent (it's reset in
137 * _DETACH, and also in kern_exit.c:wait4()
138 * Reparent the process so that the tracing
139 * proc gets to see all the action.
140 * Stop the target.
141 */
142 p->p_flag |= P_TRACED;
143 faultin(p);
144 p->p_xstat = 0; /* XXX ? */
145 if (p->p_pptr != td->td_proc) {
146 p->p_oppid = p->p_pptr->p_pid;
147 proc_reparent(p, td->td_proc);
148 }
149 psignal(p, SIGSTOP);
150 out:
151 PROC_UNLOCK(p);
152 sx_xunlock(&proctree_lock);
153 return (error);
154 }
155
156 /*
157 * Authorization check: rely on normal debugging protection, except
158 * allow processes to disengage debugging on a process onto which
159 * they have previously attached, but no longer have permission to
160 * debug.
161 */
162 PROC_LOCK(p);
163 if (op != PROCFS_CTL_DETACH &&
164 ((error = p_candebug(td, p)))) {
165 PROC_UNLOCK(p);
166 return (error);
167 }
168
169 /*
170 * Target process must be stopped, owned by (td) and
171 * be set up for tracing (P_TRACED flag set).
172 * Allow DETACH to take place at any time for sanity.
173 * Allow WAIT any time, of course.
174 */
175 switch (op) {
176 case PROCFS_CTL_DETACH:
177 case PROCFS_CTL_WAIT:
178 break;
179
180 default:
181 if (!TRACE_WAIT_P(td->td_proc, p)) {
182 PROC_UNLOCK(p);
183 return (EBUSY);
184 }
185 }
186
187
188 #ifdef FIX_SSTEP
189 /*
190 * do single-step fixup if needed
191 */
192 FIX_SSTEP(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
193 #endif
194
195 /*
196 * Don't deliver any signal by default.
197 * To continue with a signal, just send
198 * the signal name to the ctl file
199 */
200 p->p_xstat = 0;
201
202 switch (op) {
203 /*
204 * Detach. Cleans up the target process, reparent it if possible
205 * and set it running once more.
206 */
207 case PROCFS_CTL_DETACH:
208 /* if not being traced, then this is a painless no-op */
209 if ((p->p_flag & P_TRACED) == 0) {
210 PROC_UNLOCK(p);
211 return (0);
212 }
213
214 /* not being traced any more */
215 p->p_flag &= ~P_TRACED;
216
217 /* remove pending SIGTRAP, else the process will die */
218 sigqueue_delete_proc(p, SIGTRAP);
219 PROC_UNLOCK(p);
220
221 /* give process back to original parent */
222 sx_xlock(&proctree_lock);
223 if (p->p_oppid != p->p_pptr->p_pid) {
224 struct proc *pp;
225
226 pp = pfind(p->p_oppid);
227 PROC_LOCK(p);
228 if (pp) {
229 PROC_UNLOCK(pp);
230 proc_reparent(p, pp);
231 }
232 } else
233 PROC_LOCK(p);
234 p->p_oppid = 0;
235 p->p_flag &= ~P_WAITED; /* XXX ? */
236 PROC_UNLOCK(p);
237 sx_xunlock(&proctree_lock);
238
239 wakeup(td->td_proc); /* XXX for CTL_WAIT below ? */
240
241 break;
242
243 /*
244 * Step. Let the target process execute a single instruction.
245 * What does it mean to single step a threaded program?
246 */
247 case PROCFS_CTL_STEP:
248 error = proc_sstep(FIRST_THREAD_IN_PROC(p)); /* XXXKSE */
249 PROC_UNLOCK(p);
250 if (error)
251 return (error);
252 break;
253
254 /*
255 * Run. Let the target process continue running until a breakpoint
256 * or some other trap.
257 */
258 case PROCFS_CTL_RUN:
259 p->p_flag &= ~P_STOPPED_SIG; /* this uses SIGSTOP */
260 PROC_UNLOCK(p);
261 break;
262
263 /*
264 * Wait for the target process to stop.
265 * If the target is not being traced then just wait
266 * to enter
267 */
268 case PROCFS_CTL_WAIT:
269 if (p->p_flag & P_TRACED) {
270 while (error == 0 &&
271 (P_SHOULDSTOP(p)) &&
272 (p->p_flag & P_TRACED) &&
273 (p->p_pptr == td->td_proc))
274 error = msleep(p, &p->p_mtx,
275 PWAIT|PCATCH, "procfsx", 0);
276 if (error == 0 && !TRACE_WAIT_P(td->td_proc, p))
277 error = EBUSY;
278 } else {
279 while (error == 0 && P_SHOULDSTOP(p))
280 error = msleep(p, &p->p_mtx,
281 PWAIT|PCATCH, "procfs", 0);
282 }
283 PROC_UNLOCK(p);
284 return (error);
285 default:
286 panic("procfs_control");
287 }
288
289 PROC_SLOCK(p);
290 thread_unsuspend(p); /* If it can run, let it do so. */
291 PROC_SUNLOCK(p);
292 return (0);
293 }
294
295 static struct namemap *
296 findname(struct namemap *nm, char *buf, int buflen)
297 {
298
299 for (; nm->nm_name; nm++)
300 if (bcmp(buf, nm->nm_name, buflen+1) == 0)
301 return (nm);
302
303 return (0);
304 }
305
306 int
307 procfs_doprocctl(PFS_FILL_ARGS)
308 {
309 int error;
310 struct namemap *nm;
311
312 if (uio == NULL || uio->uio_rw != UIO_WRITE)
313 return (EOPNOTSUPP);
314
315 /*
316 * Map signal names into signal generation
317 * or debug control. Unknown commands and/or signals
318 * return EOPNOTSUPP.
319 *
320 * Sending a signal while the process is being debugged
321 * also has the side effect of letting the target continue
322 * to run. There is no way to single-step a signal delivery.
323 */
324 error = EOPNOTSUPP;
325
326 sbuf_trim(sb);
327 sbuf_finish(sb);
328 nm = findname(ctlnames, sbuf_data(sb), sbuf_len(sb));
329 if (nm) {
330 printf("procfs: got a %s command\n", sbuf_data(sb));
331 error = procfs_control(td, p, nm->nm_val);
332 } else {
333 nm = findname(signames, sbuf_data(sb), sbuf_len(sb));
334 if (nm) {
335 printf("procfs: got a sig%s\n", sbuf_data(sb));
336 PROC_LOCK(p);
337
338 /* This is very broken XXXKSE: */
339 if (TRACE_WAIT_P(td->td_proc, p)) {
340 p->p_xstat = nm->nm_val;
341 #ifdef FIX_SSTEP
342 /* XXXKSE: */
343 FIX_SSTEP(FIRST_THREAD_IN_PROC(p));
344 #endif
345 /* XXXKSE: */
346 p->p_flag &= ~P_STOPPED_SIG;
347 PROC_SLOCK(p);
348 thread_unsuspend(p);
349 PROC_SUNLOCK(p);
350 } else
351 psignal(p, nm->nm_val);
352 PROC_UNLOCK(p);
353 error = 0;
354 }
355 }
356
357 return (error);
358 }
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