gmon.c revision 1.19 
1/*	$NetBSD: gmon.c,v 1.19 2002/11/11 17:18:47 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 1983, 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/cdefs.h>
37#if !defined(lint) && defined(LIBC_SCCS)
38#if 0
39static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
40#else
41__RCSID("$NetBSD: gmon.c,v 1.19 2002/11/11 17:18:47 thorpej Exp $");
42#endif
43#endif
44
45#include "namespace.h"
46#include <sys/param.h>
47#include <sys/time.h>
48#include <sys/gmon.h>
49#include <sys/sysctl.h>
50
51#include <stdio.h>
52#include <stdlib.h>
53#include <fcntl.h>
54#include <limits.h>
55#include <unistd.h>
56#include <err.h>
57#include "extern.h"
58
59struct gmonparam _gmonparam = { GMON_PROF_OFF };
60
61static u_int	s_scale;
62/* see profil(2) where this is describe (incorrectly) */
63#define		SCALE_1_TO_1	0x10000L
64
65#define ERR(s) write(STDERR_FILENO, s, sizeof(s))
66
67void	moncontrol __P((int));
68void	monstartup __P((u_long, u_long));
69void	_mcleanup __P((void));
70static int hertz __P((void));
71
72
73void
74monstartup(lowpc, highpc)
75	u_long lowpc;
76	u_long highpc;
77{
78	u_long o;
79	char *cp;
80	struct gmonparam *p = &_gmonparam;
81
82	/*
83	 * round lowpc and highpc to multiples of the density we're using
84	 * so the rest of the scaling (here and in gprof) stays in ints.
85	 */
86	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
87	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
88	p->textsize = p->highpc - p->lowpc;
89	p->kcountsize = p->textsize / HISTFRACTION;
90	p->hashfraction = HASHFRACTION;
91	p->fromssize = p->textsize / p->hashfraction;
92	p->tolimit = p->textsize * ARCDENSITY / 100;
93	if (p->tolimit < MINARCS)
94		p->tolimit = MINARCS;
95	else if (p->tolimit > MAXARCS)
96		p->tolimit = MAXARCS;
97	p->tossize = p->tolimit * sizeof(struct tostruct);
98
99	cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
100	if (cp == (char *)-1) {
101		ERR("monstartup: out of memory\n");
102		return;
103	}
104#ifdef notdef
105	memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
106#endif
107	p->tos = (struct tostruct *)(void *)cp;
108	cp += (size_t)p->tossize;
109	p->kcount = (u_short *)(void *)cp;
110	cp += (size_t)p->kcountsize;
111	p->froms = (u_short *)(void *)cp;
112
113	__minbrk = sbrk((intptr_t)0);
114	p->tos[0].link = 0;
115
116	o = p->highpc - p->lowpc;
117	if (p->kcountsize < o) {
118#ifndef notdef
119		s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
120#else /* avoid floating point */
121		u_long quot = o / p->kcountsize;
122
123		if (quot >= 0x10000)
124			s_scale = 1;
125		else if (quot >= 0x100)
126			s_scale = 0x10000 / quot;
127		else if (o >= 0x800000)
128			s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
129		else
130			s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
131#endif
132	} else
133		s_scale = SCALE_1_TO_1;
134
135	moncontrol(1);
136}
137
138void
139_mcleanup()
140{
141	int fd;
142	int fromindex;
143	int endfrom;
144	u_long frompc;
145	int toindex;
146	struct rawarc rawarc;
147	struct gmonparam *p = &_gmonparam;
148	struct gmonhdr gmonhdr, *hdr;
149	struct clockinfo clockinfo;
150	int mib[2];
151	size_t size;
152	char *profdir;
153	char *proffile;
154	char  buf[PATH_MAX];
155	int len = sizeof(buf) - 1;
156#ifdef DEBUG
157	int log, len;
158	char buf2[200];
159#endif
160
161	/*
162	 * We disallow writing to the profiling file, if we are a
163	 * set{u,g}id program and our effective {u,g}id does not match
164	 * our real one.
165	 */
166	if (issetugid() && (geteuid() != getuid() || getegid() != getgid())) {
167		warnx("mcount: Profiling of set{u,g}id binaries is not"
168		    " allowed");
169		return;
170	}
171
172	if (p->state == GMON_PROF_ERROR)
173		ERR("_mcleanup: tos overflow\n");
174
175	size = sizeof(clockinfo);
176	mib[0] = CTL_KERN;
177	mib[1] = KERN_CLOCKRATE;
178	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
179		/*
180		 * Best guess
181		 */
182		clockinfo.profhz = hertz();
183	} else if (clockinfo.profhz == 0) {
184		if (clockinfo.hz != 0)
185			clockinfo.profhz = clockinfo.hz;
186		else
187			clockinfo.profhz = hertz();
188	}
189
190	moncontrol(0);
191
192	if ((profdir = getenv("PROFDIR")) != NULL) {
193		const char *s;
194		char *t;
195		pid_t pid;
196		long divisor;
197
198		/* If PROFDIR contains a null value, no profiling
199		   output is produced */
200		if (*profdir == '\0') {
201			return;
202		}
203
204		t = buf;
205		s = profdir;
206		while ((*t = *s) != '\0') {
207			if (len-- == 0) {
208				warnx("_mcleanup: internal buffer overflow, PROFDIR too long");
209				return;
210			}
211			t++;
212			s++;
213		}
214		*t++ = '/';
215
216		/*
217		 * Copy and convert pid from a pid_t to a string.  For
218		 * best performance, divisor should be initialized to
219		 * the largest power of 10 less than PID_MAX.
220		 */
221		pid = getpid();
222		divisor=10000;
223		while (divisor > pid) divisor /= 10;	/* skip leading zeros */
224		do {
225			*t++ = (char)((pid/divisor) + '0');
226			pid %= (pid_t)divisor;
227		} while (divisor /= 10);
228		*t++ = '.';
229
230		s = getprogname();
231		while ((*t++ = *s++) != '\0')
232			;
233
234		proffile = buf;
235	} else {
236		proffile = "gmon.out";
237	}
238
239	fd = open(proffile , O_CREAT|O_TRUNC|O_WRONLY, 0666);
240	if (fd < 0) {
241		warn("mcount: Cannot open `%s'", proffile);
242		return;
243	}
244#ifdef DEBUG
245	log = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
246	if (log < 0) {
247		warn("mcount: Cannot open `gmon.log'");
248		return;
249	}
250	len = snprintf(buf2, sizeof buf2, "[mcleanup1] kcount 0x%x ssiz %d\n",
251	    p->kcount, p->kcountsize);
252	write(log, buf2, len);
253#endif
254	hdr = (struct gmonhdr *)&gmonhdr;
255	hdr->lpc = p->lowpc;
256	hdr->hpc = p->highpc;
257	hdr->ncnt = (int)(p->kcountsize + sizeof(gmonhdr));
258	hdr->version = GMONVERSION;
259	hdr->profrate = clockinfo.profhz;
260	(void)write(fd, hdr, sizeof *hdr);
261	(void)write(fd, p->kcount, (size_t)p->kcountsize);
262	endfrom = (int)(p->fromssize / sizeof(*p->froms));
263	for (fromindex = 0; fromindex < endfrom; fromindex++) {
264		if (p->froms[fromindex] == 0)
265			continue;
266
267		frompc = p->lowpc;
268		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
269		for (toindex = p->froms[fromindex]; toindex != 0;
270		     toindex = p->tos[toindex].link) {
271#ifdef DEBUG
272			len = snprintf(buf2, sizeof buf2,
273			"[mcleanup2] frompc 0x%x selfpc 0x%x count %d\n" ,
274				frompc, p->tos[toindex].selfpc,
275				p->tos[toindex].count);
276			write(log, buf2, len);
277#endif
278			rawarc.raw_frompc = frompc;
279			rawarc.raw_selfpc = p->tos[toindex].selfpc;
280			rawarc.raw_count = p->tos[toindex].count;
281			write(fd, &rawarc, sizeof rawarc);
282		}
283	}
284	close(fd);
285}
286
287/*
288 * Control profiling
289 *	profiling is what mcount checks to see if
290 *	all the data structures are ready.
291 */
292void
293moncontrol(mode)
294	int mode;
295{
296	struct gmonparam *p = &_gmonparam;
297
298	if (mode) {
299		/* start */
300		profil((char *)(void *)p->kcount, (size_t)p->kcountsize,
301		    p->lowpc, s_scale);
302		p->state = GMON_PROF_ON;
303	} else {
304		/* stop */
305		profil(NULL, 0, (u_long)0, 0);
306		p->state = GMON_PROF_OFF;
307	}
308}
309
310/*
311 * discover the tick frequency of the machine
312 * if something goes wrong, we return 0, an impossible hertz.
313 */
314static int
315hertz()
316{
317	struct itimerval tim;
318
319	tim.it_interval.tv_sec = 0;
320	tim.it_interval.tv_usec = 1;
321	tim.it_value.tv_sec = 0;
322	tim.it_value.tv_usec = 0;
323	setitimer(ITIMER_REAL, &tim, 0);
324	setitimer(ITIMER_REAL, 0, &tim);
325	if (tim.it_interval.tv_usec < 2)
326		return(0);
327	return (int)(1000000 / tim.it_interval.tv_usec);
328}
329