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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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 $
39 #include <sys/param.h>
40 #include <sys/systm.h>
43 #include <sys/vnode.h>
44 #include <sys/ptrace.h>
45 #include <sys/signalvar.h>
46 #include <vfs/procfs/procfs.h>
48 #include <sys/signal2.h>
49 #include <sys/mplock2.h>
50 #include <sys/spinlock2.h>
59 * True iff process (p) is in trace wait state
60 * relative to process (curp)
62 #define TRACE_WAIT_P(curp, p) \
63 (((p)->p_stat == SSTOP) && \
64 (p)->p_pptr == (curp) && \
65 ((p)->p_flags & P_TRACED))
67 #define PROCFS_CTL_ATTACH 1
68 #define PROCFS_CTL_DETACH 2
69 #define PROCFS_CTL_STEP 3
70 #define PROCFS_CTL_RUN 4
71 #define PROCFS_CTL_WAIT 5
73 static vfs_namemap_t ctlnames[] = {
74 /* special /proc commands */
75 { "attach", PROCFS_CTL_ATTACH },
76 { "detach", PROCFS_CTL_DETACH },
77 { "step", PROCFS_CTL_STEP },
78 { "run", PROCFS_CTL_RUN },
79 { "wait", PROCFS_CTL_WAIT },
83 static 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 },
104 static int procfs_control (struct proc *curp, struct lwp *lp, int op);
107 procfs_control(struct proc *curp, struct lwp *lp, int op)
109 struct proc *p = lp->lwp_proc;
112 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
114 /* Can't trace a process that's currently exec'ing. */
115 if ((p->p_flags & P_INEXEC) != 0)
118 * Authorization check: rely on normal debugging protection, except
119 * allow processes to disengage debugging on a process onto which
120 * they have previously attached, but no longer have permission to
123 if (op != PROCFS_CTL_DETACH) {
124 if (securelevel > 0 && p->p_pid == 1)
127 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred))
132 * Attach - attaches the target process for debugging
133 * by the calling process.
135 if (op == PROCFS_CTL_ATTACH) {
136 /* check whether already being traced */
137 if (p->p_flags & P_TRACED)
140 /* can't trace yourself! */
141 if (p->p_pid == curp->p_pid)
145 * Go ahead and set the trace flag.
146 * Save the old parent (it's reset in
147 * _DETACH, and also in kern_exit.c:wait4()
148 * Reparent the process so that the tracing
149 * proc gets to see all the action.
152 p->p_flags |= P_TRACED;
154 p->p_xstat = 0; /* XXX ? */
155 if (p->p_pptr != curp) {
156 p->p_oppid = p->p_pptr->p_pid;
157 proc_reparent(p, curp);
164 * Target process must be stopped, owned by (curp) and
165 * be set up for tracing (P_TRACED flag set).
166 * Allow DETACH to take place at any time for sanity.
167 * Allow WAIT any time, of course.
170 case PROCFS_CTL_DETACH:
171 case PROCFS_CTL_WAIT:
175 if (!TRACE_WAIT_P(curp, p))
182 * do single-step fixup if needed
188 * Don't deliver any signal by default.
189 * To continue with a signal, just send
190 * the signal name to the ctl file
196 * Detach. Cleans up the target process, reparent it if possible
197 * and set it running once more.
199 case PROCFS_CTL_DETACH:
200 /* if not being traced, then this is a painless no-op */
201 if ((p->p_flags & P_TRACED) == 0)
204 /* not being traced any more */
205 p->p_flags &= ~P_TRACED;
207 /* remove pending SIGTRAP, else the process will die */
208 spin_lock(&lp->lwp_spin);
209 lwp_delsig(lp, SIGTRAP, 1);
210 spin_unlock(&lp->lwp_spin);
212 /* give process back to original parent */
213 if (p->p_oppid != p->p_pptr->p_pid) {
216 pp = pfs_pfind(p->p_oppid);
218 proc_reparent(p, pp);
224 p->p_flags &= ~P_WAITED; /* XXX ? */
225 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */
230 * Step. Let the target process execute a single instruction.
232 case PROCFS_CTL_STEP:
234 error = procfs_sstep(lp);
241 * Run. Let the target process continue running until a breakpoint
242 * or some other trap.
248 * Wait for the target process to stop.
249 * If the target is not being traced then just wait
252 case PROCFS_CTL_WAIT:
254 if (p->p_flags & P_TRACED) {
256 p->p_stat != SSTOP &&
257 (p->p_flags & P_TRACED) &&
258 (p->p_pptr == curp)) {
259 error = tsleep((caddr_t) p,
260 PCATCH, "procfsx", 0);
262 if (error == 0 && !TRACE_WAIT_P(curp, p))
265 while (error == 0 && p->p_stat != SSTOP) {
266 error = tsleep((caddr_t) p,
267 PCATCH, "procfs", 0);
273 panic("procfs_control");
277 * If the process is in a stopped state, make it runnable again.
278 * Do not set LWP_MP_BREAKTSLEEP - that is, do not break a tsleep
279 * that might be in progress.
281 if (p->p_stat == SSTOP)
282 proc_unstop(p, SSTOP);
287 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
290 struct proc *p = lp->lwp_proc;
293 char msg[PROCFS_CTLLEN+1];
296 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
298 if (uio->uio_rw != UIO_WRITE)
301 xlen = PROCFS_CTLLEN;
302 error = vfs_getuserstr(uio, msg, &xlen);
307 * Map signal names into signal generation
308 * or debug control. Unknown commands and/or signals
311 * Sending a signal while the process is being debugged
312 * also has the side effect of letting the target continue
313 * to run. There is no way to single-step a signal delivery.
317 nm = vfs_findname(ctlnames, msg, xlen);
319 error = procfs_control(curp, lp, nm->nm_val);
321 nm = vfs_findname(signames, msg, xlen);
323 if (TRACE_WAIT_P(curp, p)) {
324 p->p_xstat = nm->nm_val;
329 * Make the process runnable but do not
332 proc_unstop(p, SSTOP);
334 ksignal(p, nm->nm_val);