gmon.c revision 1.29
1/*	$NetBSD: gmon.c,v 1.29 2006/10/15 16:14:46 christos Exp $	*/
2
3/*
4 * Copyright (c) 2003, 2004 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Nathan J. Williams for Wasabi Systems, Inc.
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 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *	This product includes software developed for the NetBSD Project by
20 *	Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 *    or promote products derived from this software without specific prior
23 *    written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38/*-
39 * Copyright (c) 1983, 1992, 1993
40 *	The Regents of the University of California.  All rights reserved.
41 *
42 * Redistribution and use in source and binary forms, with or without
43 * modification, are permitted provided that the following conditions
44 * are met:
45 * 1. Redistributions of source code must retain the above copyright
46 *    notice, this list of conditions and the following disclaimer.
47 * 2. Redistributions in binary form must reproduce the above copyright
48 *    notice, this list of conditions and the following disclaimer in the
49 *    documentation and/or other materials provided with the distribution.
50 * 3. Neither the name of the University nor the names of its contributors
51 *    may be used to endorse or promote products derived from this software
52 *    without specific prior written permission.
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * SUCH DAMAGE.
65 */
66
67#include <sys/cdefs.h>
68#if !defined(lint) && defined(LIBC_SCCS)
69#if 0
70static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
71#else
72__RCSID("$NetBSD: gmon.c,v 1.29 2006/10/15 16:14:46 christos Exp $");
73#endif
74#endif
75
76#include "namespace.h"
77#include <sys/param.h>
78#include <sys/time.h>
79#include <sys/gmon.h>
80#include <sys/mman.h>
81#include <sys/sysctl.h>
82
83#include <stdio.h>
84#include <stdlib.h>
85#include <string.h>
86#include <fcntl.h>
87#include <limits.h>
88#include <unistd.h>
89#include <err.h>
90#include "extern.h"
91#include "reentrant.h"
92
93struct gmonparam _gmonparam = { .state = GMON_PROF_OFF };
94
95#ifdef _REENTRANT
96struct gmonparam *_gmonfree;
97struct gmonparam *_gmoninuse;
98mutex_t _gmonlock = MUTEX_INITIALIZER;
99thread_key_t _gmonkey;
100struct gmonparam _gmondummy;
101#endif
102
103static u_int	s_scale;
104/* see profil(2) where this is describe (incorrectly) */
105#define		SCALE_1_TO_1	0x10000L
106
107#define ERR(s) write(STDERR_FILENO, s, sizeof(s))
108
109void	moncontrol __P((int));
110void	monstartup __P((u_long, u_long));
111void	_mcleanup __P((void));
112static int hertz __P((void));
113
114#ifdef _REENTRANT
115static void _m_gmon_destructor(void *);
116struct gmonparam *_m_gmon_alloc(void)  __attribute__((__no_instrument_function__));
117static void _m_gmon_merge(void);
118static void _m_gmon_merge_two(struct gmonparam *, struct gmonparam *);
119#endif
120
121void
122monstartup(lowpc, highpc)
123	u_long lowpc;
124	u_long highpc;
125{
126	u_long o;
127	char *cp;
128	struct gmonparam *p = &_gmonparam;
129
130	/*
131	 * round lowpc and highpc to multiples of the density we're using
132	 * so the rest of the scaling (here and in gprof) stays in ints.
133	 */
134	p->lowpc = rounddown(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
135	p->highpc = roundup(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
136	p->textsize = p->highpc - p->lowpc;
137	p->kcountsize = p->textsize / HISTFRACTION;
138	p->hashfraction = HASHFRACTION;
139	p->fromssize = p->textsize / p->hashfraction;
140	p->tolimit = p->textsize * ARCDENSITY / 100;
141	if (p->tolimit < MINARCS)
142		p->tolimit = MINARCS;
143	else if (p->tolimit > MAXARCS)
144		p->tolimit = MAXARCS;
145	p->tossize = p->tolimit * sizeof(struct tostruct);
146
147	cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
148	if (cp == (char *)-1) {
149		ERR("monstartup: out of memory\n");
150		return;
151	}
152#ifdef notdef
153	memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
154#endif
155	p->tos = (struct tostruct *)(void *)cp;
156	cp += (size_t)p->tossize;
157	p->kcount = (u_short *)(void *)cp;
158	cp += (size_t)p->kcountsize;
159	p->froms = (u_short *)(void *)cp;
160
161	__minbrk = sbrk((intptr_t)0);
162	p->tos[0].link = 0;
163
164	o = p->highpc - p->lowpc;
165	if (p->kcountsize < o) {
166#ifndef notdef
167		s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
168#else /* avoid floating point */
169		u_long quot = o / p->kcountsize;
170
171		if (quot >= 0x10000)
172			s_scale = 1;
173		else if (quot >= 0x100)
174			s_scale = 0x10000 / quot;
175		else if (o >= 0x800000)
176			s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
177		else
178			s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
179#endif
180	} else
181		s_scale = SCALE_1_TO_1;
182
183#ifdef _REENTRANT
184	_gmondummy.state = GMON_PROF_BUSY;
185	thr_keycreate(&_gmonkey, _m_gmon_destructor);
186#endif
187	moncontrol(1);
188}
189
190#ifdef _REENTRANT
191static void
192_m_gmon_destructor(void *arg)
193{
194	struct gmonparam *p = arg, *q, **prev;
195
196	if (p == &_gmondummy)
197		return;
198
199	thr_setspecific(_gmonkey, &_gmondummy);
200
201	mutex_lock(&_gmonlock);
202	/* XXX eww, linear list traversal. */
203	for (q = _gmoninuse, prev = &_gmoninuse;
204	     q != NULL;
205	     prev = (struct gmonparam **)(void *)&q->kcount,	/* XXX */
206		 q = (struct gmonparam *)(void *)q->kcount) {
207		if (q == p)
208			*prev = (struct gmonparam *)(void *)q->kcount;
209	}
210	p->kcount = (u_short *)(void *)_gmonfree;
211	_gmonfree = p;
212	mutex_unlock(&_gmonlock);
213
214	thr_setspecific(_gmonkey, NULL);
215}
216
217struct gmonparam *
218_m_gmon_alloc(void)
219{
220	struct gmonparam *p;
221	char *cp;
222
223	mutex_lock(&_gmonlock);
224	if (_gmonfree != NULL) {
225		p = _gmonfree;
226		_gmonfree = (struct gmonparam *)(void *)p->kcount;
227		p->kcount = (u_short *)(void *)_gmoninuse;
228		_gmoninuse = p;
229	} else {
230		mutex_unlock(&_gmonlock);
231		cp = mmap(NULL,
232		    (size_t)(sizeof (struct gmonparam) +
233			_gmonparam.fromssize + _gmonparam.tossize),
234		    PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0LL);
235		p = (void *)cp;
236		*p = _gmonparam;
237		p->kcount = NULL;
238		cp += sizeof (struct gmonparam);
239		memset(cp, 0, (size_t)(p->fromssize + p->tossize));
240		p->froms = (u_short *)(void *)cp;
241		p->tos = (struct tostruct *)(void *)(cp + p->fromssize);
242		mutex_lock(&_gmonlock);
243		p->kcount = (u_short *)(void *)_gmoninuse;
244		_gmoninuse = p;
245	}
246	mutex_unlock(&_gmonlock);
247	thr_setspecific(_gmonkey, p);
248
249	return p;
250}
251
252static void
253_m_gmon_merge_two(struct gmonparam *p, struct gmonparam *q)
254{
255	u_long fromindex;
256	u_short *frompcindex, qtoindex, toindex;
257	u_long selfpc;
258	int endfrom;
259	long count;
260	struct tostruct *top;
261
262	endfrom = (int)(q->fromssize / sizeof(*q->froms));
263	for (fromindex = 0; fromindex < endfrom; fromindex++) {
264		if (q->froms[fromindex] == 0)
265			continue;
266		for (qtoindex = q->froms[fromindex]; qtoindex != 0;
267		     qtoindex = q->tos[qtoindex].link) {
268			selfpc = q->tos[qtoindex].selfpc;
269			count = q->tos[qtoindex].count;
270			/* cribbed from mcount */
271			frompcindex = &p->froms[fromindex];
272			toindex = *frompcindex;
273			if (toindex == 0) {
274				/*
275				 *	first time traversing this arc
276				 */
277				toindex = ++p->tos[0].link;
278				if (toindex >= p->tolimit)
279					/* halt further profiling */
280					goto overflow;
281
282				*frompcindex = (u_short)toindex;
283				top = &p->tos[(size_t)toindex];
284				top->selfpc = selfpc;
285				top->count = count;
286				top->link = 0;
287				goto done;
288			}
289			top = &p->tos[(size_t)toindex];
290			if (top->selfpc == selfpc) {
291				/*
292				 * arc at front of chain; usual case.
293				 */
294				top->count+= count;
295				goto done;
296			}
297			/*
298			 * have to go looking down chain for it.
299			 * top points to what we are looking at,
300			 * we know it is not at the head of the chain.
301			 */
302			for (; /* goto done */; ) {
303				if (top->link == 0) {
304					/*
305					 * top is end of the chain and
306					 * none of the chain had
307					 * top->selfpc == selfpc.  so
308					 * we allocate a new tostruct
309					 * and link it to the head of
310					 * the chain.
311					 */
312					toindex = ++p->tos[0].link;
313					if (toindex >= p->tolimit)
314						goto overflow;
315
316					top = &p->tos[(size_t)toindex];
317					top->selfpc = selfpc;
318					top->count = count;
319					top->link = *frompcindex;
320					*frompcindex = (u_short)toindex;
321					goto done;
322				}
323				/*
324				 * otherwise, check the next arc on the chain.
325				 */
326				top = &p->tos[top->link];
327				if (top->selfpc == selfpc) {
328					/*
329					 * there it is.
330					 * add to its count.
331					 */
332					top->count += count;
333					goto done;
334				}
335
336			}
337
338		done: ;
339		}
340
341	}
342 overflow: ;
343
344}
345
346static void
347_m_gmon_merge(void)
348{
349	struct gmonparam *q;
350
351	mutex_lock(&_gmonlock);
352
353	for (q = _gmonfree; q != NULL; q = (struct gmonparam *)(void *)q->kcount)
354		_m_gmon_merge_two(&_gmonparam, q);
355
356	for (q = _gmoninuse; q != NULL; q = (struct gmonparam *)(void *)q->kcount) {
357		q->state = GMON_PROF_OFF;
358		_m_gmon_merge_two(&_gmonparam, q);
359	}
360
361	mutex_unlock(&_gmonlock);
362}
363#endif
364
365void
366_mcleanup()
367{
368	int fd;
369	int fromindex;
370	int endfrom;
371	u_long frompc;
372	int toindex;
373	struct rawarc rawarc;
374	struct gmonparam *p = &_gmonparam;
375	struct gmonhdr gmonhdr, *hdr;
376	struct clockinfo clockinfo;
377	int mib[2];
378	size_t size;
379	char *profdir;
380	const char *proffile;
381	char  buf[PATH_MAX];
382#ifdef DEBUG
383	int logfd, len;
384	char buf2[200];
385#endif
386
387	/*
388	 * We disallow writing to the profiling file, if we are a
389	 * set{u,g}id program and our effective {u,g}id does not match
390	 * our real one.
391	 */
392	if (issetugid() && (geteuid() != getuid() || getegid() != getgid())) {
393		warnx("mcount: Profiling of set{u,g}id binaries is not"
394		    " allowed");
395		return;
396	}
397
398	if (p->state == GMON_PROF_ERROR)
399		ERR("_mcleanup: tos overflow\n");
400
401	size = sizeof(clockinfo);
402	mib[0] = CTL_KERN;
403	mib[1] = KERN_CLOCKRATE;
404	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
405		/*
406		 * Best guess
407		 */
408		clockinfo.profhz = hertz();
409	} else if (clockinfo.profhz == 0) {
410		if (clockinfo.hz != 0)
411			clockinfo.profhz = clockinfo.hz;
412		else
413			clockinfo.profhz = hertz();
414	}
415
416	moncontrol(0);
417
418	if ((profdir = getenv("PROFDIR")) != NULL) {
419		/* If PROFDIR contains a null value, no profiling
420		   output is produced */
421		if (*profdir == '\0')
422			return;
423
424		if (snprintf(buf, sizeof buf, "%s/%d.%s",
425			    profdir, getpid(), getprogname()) >= sizeof buf) {
426			warnx("_mcleanup: internal buffer overflow, PROFDIR too long");
427			return;
428		}
429
430		proffile = buf;
431	} else {
432		proffile = "gmon.out";
433	}
434
435	fd = open(proffile , O_CREAT|O_TRUNC|O_WRONLY, 0666);
436	if (fd < 0) {
437		warn("mcount: Cannot open `%s'", proffile);
438		return;
439	}
440#ifdef DEBUG
441	logfd = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
442	if (logfd < 0) {
443		warn("mcount: Cannot open `gmon.log'");
444		return;
445	}
446	len = snprintf(buf2, sizeof buf2, "[mcleanup1] kcount %p ssiz %lu\n",
447	    p->kcount, p->kcountsize);
448	(void)write(logfd, buf2, (size_t)len);
449#endif
450#ifdef _REENTRANT
451	_m_gmon_merge();
452#endif
453	hdr = (struct gmonhdr *)&gmonhdr;
454	hdr->lpc = p->lowpc;
455	hdr->hpc = p->highpc;
456	hdr->ncnt = (int)(p->kcountsize + sizeof(gmonhdr));
457	hdr->version = GMONVERSION;
458	hdr->profrate = clockinfo.profhz;
459	(void)write(fd, hdr, sizeof *hdr);
460	(void)write(fd, p->kcount, (size_t)p->kcountsize);
461	endfrom = (int)(p->fromssize / sizeof(*p->froms));
462	for (fromindex = 0; fromindex < endfrom; fromindex++) {
463		if (p->froms[fromindex] == 0)
464			continue;
465
466		frompc = p->lowpc;
467		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
468		for (toindex = p->froms[fromindex]; toindex != 0;
469		     toindex = p->tos[toindex].link) {
470#ifdef DEBUG
471			len = snprintf(buf2, sizeof buf2,
472			"[mcleanup2] frompc 0x%lx selfpc 0x%lx count %lu\n" ,
473				(u_long)frompc, (u_long)p->tos[toindex].selfpc,
474				(u_long)p->tos[toindex].count);
475			(void)write(logfd, buf2, (size_t)len);
476#endif
477			rawarc.raw_frompc = frompc;
478			rawarc.raw_selfpc = p->tos[toindex].selfpc;
479			rawarc.raw_count = p->tos[toindex].count;
480			write(fd, &rawarc, sizeof rawarc);
481		}
482	}
483	close(fd);
484}
485
486/*
487 * Control profiling
488 *	profiling is what mcount checks to see if
489 *	all the data structures are ready.
490 */
491void
492moncontrol(mode)
493	int mode;
494{
495	struct gmonparam *p = &_gmonparam;
496
497	if (mode) {
498		/* start */
499		profil((char *)(void *)p->kcount, (size_t)p->kcountsize,
500		    p->lowpc, s_scale);
501		p->state = GMON_PROF_ON;
502	} else {
503		/* stop */
504		profil(NULL, 0, (u_long)0, 0);
505		p->state = GMON_PROF_OFF;
506	}
507}
508
509/*
510 * discover the tick frequency of the machine
511 * if something goes wrong, we return 0, an impossible hertz.
512 */
513static int
514hertz()
515{
516	struct itimerval tim;
517
518	tim.it_interval.tv_sec = 0;
519	tim.it_interval.tv_usec = 1;
520	tim.it_value.tv_sec = 0;
521	tim.it_value.tv_usec = 0;
522	setitimer(ITIMER_REAL, &tim, 0);
523	setitimer(ITIMER_REAL, 0, &tim);
524	if (tim.it_interval.tv_usec < 2)
525		return(0);
526	return (int)(1000000 / tim.it_interval.tv_usec);
527}
528