xref: /freebsd/sys/kern/tty_info.c (revision f5147e312f43a9050468de539aeafa072caa1a60)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1990, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Copyright (c) 2002 Networks Associates Technologies, Inc.
13  * All rights reserved.
14  *
15  * Portions of this software were developed for the FreeBSD Project by
16  * ThinkSec AS and NAI Labs, the Security Research Division of Network
17  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
18  * ("CBOSS"), as part of the DARPA CHATS research program.
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  * 1. Redistributions of source code must retain the above copyright
24  *    notice, this list of conditions and the following disclaimer.
25  * 2. Redistributions in binary form must reproduce the above copyright
26  *    notice, this list of conditions and the following disclaimer in the
27  *    documentation and/or other materials provided with the distribution.
28  * 3. Neither the name of the University nor the names of its contributors
29  *    may be used to endorse or promote products derived from this software
30  *    without specific prior written permission.
31  *
32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42  * SUCH DAMAGE.
43  */
44 
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include <sys/param.h>
49 #include <sys/lock.h>
50 #include <sys/mutex.h>
51 #include <sys/proc.h>
52 #include <sys/resourcevar.h>
53 #include <sys/sched.h>
54 #include <sys/systm.h>
55 #include <sys/tty.h>
56 
57 #include <vm/vm.h>
58 #include <vm/pmap.h>
59 #include <vm/vm_map.h>
60 
61 /*
62  * Returns 1 if p2 is "better" than p1
63  *
64  * The algorithm for picking the "interesting" process is thus:
65  *
66  *	1) Only foreground processes are eligible - implied.
67  *	2) Runnable processes are favored over anything else.  The runner
68  *	   with the highest cpu utilization is picked (p_estcpu).  Ties are
69  *	   broken by picking the highest pid.
70  *	3) The sleeper with the shortest sleep time is next.  With ties,
71  *	   we pick out just "short-term" sleepers (P_SINTR == 0).
72  *	4) Further ties are broken by picking the highest pid.
73  */
74 
75 #define TESTAB(a, b)    ((a)<<1 | (b))
76 #define ONLYA   2
77 #define ONLYB   1
78 #define BOTH    3
79 
80 static int
81 proc_sum(struct proc *p, fixpt_t *estcpup)
82 {
83 	struct thread *td;
84 	int estcpu;
85 	int val;
86 
87 	val = 0;
88 	estcpu = 0;
89 	FOREACH_THREAD_IN_PROC(p, td) {
90 		thread_lock(td);
91 		if (TD_ON_RUNQ(td) ||
92 		    TD_IS_RUNNING(td))
93 			val = 1;
94 		estcpu += sched_pctcpu(td);
95 		thread_unlock(td);
96 	}
97 	*estcpup = estcpu;
98 
99 	return (val);
100 }
101 
102 static int
103 thread_compare(struct thread *td, struct thread *td2)
104 {
105 	int runa, runb;
106 	int slpa, slpb;
107 	fixpt_t esta, estb;
108 
109 	if (td == NULL)
110 		return (1);
111 
112 	/*
113 	 * Fetch running stats, pctcpu usage, and interruptable flag.
114 	 */
115 	thread_lock(td);
116 	runa = TD_IS_RUNNING(td) | TD_ON_RUNQ(td);
117 	slpa = td->td_flags & TDF_SINTR;
118 	esta = sched_pctcpu(td);
119 	thread_unlock(td);
120 	thread_lock(td2);
121 	runb = TD_IS_RUNNING(td2) | TD_ON_RUNQ(td2);
122 	estb = sched_pctcpu(td2);
123 	slpb = td2->td_flags & TDF_SINTR;
124 	thread_unlock(td2);
125 	/*
126 	 * see if at least one of them is runnable
127 	 */
128 	switch (TESTAB(runa, runb)) {
129 	case ONLYA:
130 		return (0);
131 	case ONLYB:
132 		return (1);
133 	case BOTH:
134 		break;
135 	}
136 	/*
137 	 *  favor one with highest recent cpu utilization
138 	 */
139 	if (estb > esta)
140 		return (1);
141 	if (esta > estb)
142 		return (0);
143 	/*
144 	 * favor one sleeping in a non-interruptible sleep
145 	 */
146 	switch (TESTAB(slpa, slpb)) {
147 	case ONLYA:
148 		return (0);
149 	case ONLYB:
150 		return (1);
151 	case BOTH:
152 		break;
153 	}
154 
155 	return (td < td2);
156 }
157 
158 static int
159 proc_compare(struct proc *p1, struct proc *p2)
160 {
161 
162 	int runa, runb;
163 	fixpt_t esta, estb;
164 
165 	if (p1 == NULL)
166 		return (1);
167 
168 	/*
169 	 * Fetch various stats about these processes.  After we drop the
170 	 * lock the information could be stale but the race is unimportant.
171 	 */
172 	PROC_LOCK(p1);
173 	runa = proc_sum(p1, &esta);
174 	PROC_UNLOCK(p1);
175 	PROC_LOCK(p2);
176 	runb = proc_sum(p2, &estb);
177 	PROC_UNLOCK(p2);
178 
179 	/*
180 	 * see if at least one of them is runnable
181 	 */
182 	switch (TESTAB(runa, runb)) {
183 	case ONLYA:
184 		return (0);
185 	case ONLYB:
186 		return (1);
187 	case BOTH:
188 		break;
189 	}
190 	/*
191 	 *  favor one with highest recent cpu utilization
192 	 */
193 	if (estb > esta)
194 		return (1);
195 	if (esta > estb)
196 		return (0);
197 	/*
198 	 * weed out zombies
199 	 */
200 	switch (TESTAB(p1->p_state == PRS_ZOMBIE, p2->p_state == PRS_ZOMBIE)) {
201 	case ONLYA:
202 		return (1);
203 	case ONLYB:
204 		return (0);
205 	case BOTH:
206 		break;
207 	}
208 
209 	return (p2->p_pid > p1->p_pid);		/* tie - return highest pid */
210 }
211 
212 /*
213  * Report on state of foreground process group.
214  */
215 void
216 tty_info(struct tty *tp)
217 {
218 	struct timeval rtime, utime, stime;
219 	struct proc *p, *ppick;
220 	struct thread *td, *tdpick;
221 	const char *stateprefix, *state;
222 	long rss;
223 	int load, pctcpu;
224 	pid_t pid;
225 	char comm[MAXCOMLEN + 1];
226 	struct rusage ru;
227 
228 	tty_lock_assert(tp, MA_OWNED);
229 
230 	if (tty_checkoutq(tp) == 0)
231 		return;
232 
233 	/* Print load average. */
234 	load = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
235 	ttyprintf(tp, "%sload: %d.%02d ", tp->t_column == 0 ? "" : "\n",
236 	    load / 100, load % 100);
237 
238 	if (tp->t_session == NULL) {
239 		ttyprintf(tp, "not a controlling terminal\n");
240 		return;
241 	}
242 	if (tp->t_pgrp == NULL) {
243 		ttyprintf(tp, "no foreground process group\n");
244 		return;
245 	}
246 	PGRP_LOCK(tp->t_pgrp);
247 	if (LIST_EMPTY(&tp->t_pgrp->pg_members)) {
248 		PGRP_UNLOCK(tp->t_pgrp);
249 		ttyprintf(tp, "empty foreground process group\n");
250 		return;
251 	}
252 
253 	/*
254 	 * Pick the most interesting process and copy some of its
255 	 * state for printing later.  This operation could rely on stale
256 	 * data as we can't hold the proc slock or thread locks over the
257 	 * whole list. However, we're guaranteed not to reference an exited
258 	 * thread or proc since we hold the tty locked.
259 	 */
260 	p = NULL;
261 	LIST_FOREACH(ppick, &tp->t_pgrp->pg_members, p_pglist)
262 		if (proc_compare(p, ppick))
263 			p = ppick;
264 
265 	PROC_LOCK(p);
266 	PGRP_UNLOCK(tp->t_pgrp);
267 	td = NULL;
268 	FOREACH_THREAD_IN_PROC(p, tdpick)
269 		if (thread_compare(td, tdpick))
270 			td = tdpick;
271 	stateprefix = "";
272 	thread_lock(td);
273 	if (TD_IS_RUNNING(td))
274 		state = "running";
275 	else if (TD_ON_RUNQ(td) || TD_CAN_RUN(td))
276 		state = "runnable";
277 	else if (TD_IS_SLEEPING(td)) {
278 		/* XXX: If we're sleeping, are we ever not in a queue? */
279 		if (TD_ON_SLEEPQ(td))
280 			state = td->td_wmesg;
281 		else
282 			state = "sleeping without queue";
283 	} else if (TD_ON_LOCK(td)) {
284 		state = td->td_lockname;
285 		stateprefix = "*";
286 	} else if (TD_IS_SUSPENDED(td))
287 		state = "suspended";
288 	else if (TD_AWAITING_INTR(td))
289 		state = "intrwait";
290 	else if (p->p_state == PRS_ZOMBIE)
291 		state = "zombie";
292 	else
293 		state = "unknown";
294 	pctcpu = (sched_pctcpu(td) * 10000 + FSCALE / 2) >> FSHIFT;
295 	thread_unlock(td);
296 	if (p->p_state == PRS_NEW || p->p_state == PRS_ZOMBIE)
297 		rss = 0;
298 	else
299 		rss = pgtok(vmspace_resident_count(p->p_vmspace));
300 	microuptime(&rtime);
301 	timevalsub(&rtime, &p->p_stats->p_start);
302 	rufetchcalc(p, &ru, &utime, &stime);
303 	pid = p->p_pid;
304 	strlcpy(comm, p->p_comm, sizeof comm);
305 	PROC_UNLOCK(p);
306 
307 	/* Print command, pid, state, rtime, utime, stime, %cpu, and rss. */
308 	ttyprintf(tp,
309 	    " cmd: %s %d [%s%s] %ld.%02ldr %ld.%02ldu %ld.%02lds %d%% %ldk\n",
310 	    comm, pid, stateprefix, state,
311 	    (long)rtime.tv_sec, rtime.tv_usec / 10000,
312 	    (long)utime.tv_sec, utime.tv_usec / 10000,
313 	    (long)stime.tv_sec, stime.tv_usec / 10000,
314 	    pctcpu / 100, rss);
315 }
316