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
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10 * modification, are permitted provided that the following conditions
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19 * This product includes software developed by the University of
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37 * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
40 * $FreeBSD: src/sys/miscfs/procfs/procfs_ctl.c,v 1.20.2.2 2002/01/22 17:22:59 nectar Exp $
41 * $DragonFly: src/sys/vfs/procfs/procfs_ctl.c,v 1.16 2007/03/12 21:08:15 corecode Exp $
44 #include <sys/param.h>
45 #include <sys/systm.h>
48 #include <sys/vnode.h>
49 #include <sys/ptrace.h>
50 #include <sys/signalvar.h>
51 #include <vfs/procfs/procfs.h>
53 #include <sys/signal2.h>
54 #include <sys/thread2.h>
55 #include <sys/mplock2.h>
64 * True iff process (p) is in trace wait state
65 * relative to process (curp)
67 #define TRACE_WAIT_P(curp, p) \
68 (((p)->p_stat == SSTOP) && \
69 (p)->p_pptr == (curp) && \
70 ((p)->p_flag & P_TRACED))
72 #define PROCFS_CTL_ATTACH 1
73 #define PROCFS_CTL_DETACH 2
74 #define PROCFS_CTL_STEP 3
75 #define PROCFS_CTL_RUN 4
76 #define PROCFS_CTL_WAIT 5
78 static vfs_namemap_t ctlnames[] = {
79 /* special /proc commands */
80 { "attach", PROCFS_CTL_ATTACH },
81 { "detach", PROCFS_CTL_DETACH },
82 { "step", PROCFS_CTL_STEP },
83 { "run", PROCFS_CTL_RUN },
84 { "wait", PROCFS_CTL_WAIT },
88 static vfs_namemap_t signames[] = {
89 /* regular signal names */
90 { "hup", SIGHUP }, { "int", SIGINT },
91 { "quit", SIGQUIT }, { "ill", SIGILL },
92 { "trap", SIGTRAP }, { "abrt", SIGABRT },
93 { "iot", SIGIOT }, { "emt", SIGEMT },
94 { "fpe", SIGFPE }, { "kill", SIGKILL },
95 { "bus", SIGBUS }, { "segv", SIGSEGV },
96 { "sys", SIGSYS }, { "pipe", SIGPIPE },
97 { "alrm", SIGALRM }, { "term", SIGTERM },
98 { "urg", SIGURG }, { "stop", SIGSTOP },
99 { "tstp", SIGTSTP }, { "cont", SIGCONT },
100 { "chld", SIGCHLD }, { "ttin", SIGTTIN },
101 { "ttou", SIGTTOU }, { "io", SIGIO },
102 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
103 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
104 { "winch", SIGWINCH }, { "info", SIGINFO },
105 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
109 static int procfs_control (struct proc *curp, struct lwp *lp, int op);
112 procfs_control(struct proc *curp, struct lwp *lp, int op)
114 struct proc *p = lp->lwp_proc;
117 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
118 ASSERT_LWKT_TOKEN_HELD(&proc_token);
120 /* Can't trace a process that's currently exec'ing. */
121 if ((p->p_flag & P_INEXEC) != 0)
124 * Authorization check: rely on normal debugging protection, except
125 * allow processes to disengage debugging on a process onto which
126 * they have previously attached, but no longer have permission to
129 if (op != PROCFS_CTL_DETACH) {
130 if (securelevel > 0 && p->p_pid == 1)
133 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred))
138 * Attach - attaches the target process for debugging
139 * by the calling process.
141 if (op == PROCFS_CTL_ATTACH) {
142 /* check whether already being traced */
143 if (p->p_flag & P_TRACED)
146 /* can't trace yourself! */
147 if (p->p_pid == curp->p_pid)
151 * Go ahead and set the trace flag.
152 * Save the old parent (it's reset in
153 * _DETACH, and also in kern_exit.c:wait4()
154 * Reparent the process so that the tracing
155 * proc gets to see all the action.
158 p->p_flag |= P_TRACED;
160 p->p_xstat = 0; /* XXX ? */
161 if (p->p_pptr != curp) {
162 p->p_oppid = p->p_pptr->p_pid;
163 proc_reparent(p, curp);
170 * Target process must be stopped, owned by (curp) 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.
176 case PROCFS_CTL_DETACH:
177 case PROCFS_CTL_WAIT:
181 if (!TRACE_WAIT_P(curp, p))
188 * do single-step fixup if needed
194 * Don't deliver any signal by default.
195 * To continue with a signal, just send
196 * the signal name to the ctl file
202 * Detach. Cleans up the target process, reparent it if possible
203 * and set it running once more.
205 case PROCFS_CTL_DETACH:
206 /* if not being traced, then this is a painless no-op */
207 if ((p->p_flag & P_TRACED) == 0)
210 /* not being traced any more */
211 p->p_flag &= ~P_TRACED;
213 /* remove pending SIGTRAP, else the process will die */
214 lwp_delsig(lp, SIGTRAP);
216 /* give process back to original parent */
217 if (p->p_oppid != p->p_pptr->p_pid) {
220 pp = pfind(p->p_oppid);
222 proc_reparent(p, pp);
228 p->p_flag &= ~P_WAITED; /* XXX ? */
229 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */
234 * Step. Let the target process execute a single instruction.
236 case PROCFS_CTL_STEP:
238 error = procfs_sstep(lp);
245 * Run. Let the target process continue running until a breakpoint
246 * or some other trap.
252 * Wait for the target process to stop.
253 * If the target is not being traced then just wait
256 case PROCFS_CTL_WAIT:
258 if (p->p_flag & P_TRACED) {
260 p->p_stat != SSTOP &&
261 (p->p_flag & P_TRACED) &&
262 (p->p_pptr == curp)) {
263 error = tsleep((caddr_t) p,
264 PCATCH, "procfsx", 0);
266 if (error == 0 && !TRACE_WAIT_P(curp, p))
269 while (error == 0 && p->p_stat != SSTOP) {
270 error = tsleep((caddr_t) p,
271 PCATCH, "procfs", 0);
277 panic("procfs_control");
281 * If the process is in a stopped state, make it runnable again.
282 * Do not set LWP_BREAKTSLEEP - that is, do not break a tsleep that
283 * might be in progress.
285 if (p->p_stat == SSTOP)
291 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
294 struct proc *p = lp->lwp_proc;
297 char msg[PROCFS_CTLLEN+1];
300 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
301 ASSERT_LWKT_TOKEN_HELD(&proc_token);
303 if (uio->uio_rw != UIO_WRITE)
306 xlen = PROCFS_CTLLEN;
307 error = vfs_getuserstr(uio, msg, &xlen);
312 * Map signal names into signal generation
313 * or debug control. Unknown commands and/or signals
316 * Sending a signal while the process is being debugged
317 * also has the side effect of letting the target continue
318 * to run. There is no way to single-step a signal delivery.
322 nm = vfs_findname(ctlnames, msg, xlen);
324 error = procfs_control(curp, lp, nm->nm_val);
326 nm = vfs_findname(signames, msg, xlen);
328 if (TRACE_WAIT_P(curp, p)) {
329 p->p_xstat = nm->nm_val;
334 * Make the process runnable but do not
339 ksignal(p, nm->nm_val);