gmon.c revision 1.19 
1/*	$OpenBSD: gmon.c,v 1.19 2005/08/08 08:05:34 espie Exp $ */
2/*-
3 * Copyright (c) 1983, 1992, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/param.h>
32#include <sys/time.h>
33#include <sys/gmon.h>
34#include <sys/sysctl.h>
35
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <fcntl.h>
40#include <limits.h>
41#include <unistd.h>
42
43extern char *minbrk __asm ("minbrk");
44
45struct gmonparam _gmonparam = { GMON_PROF_OFF };
46
47static int	s_scale;
48/* see profil(2) where this is describe (incorrectly) */
49#define		SCALE_1_TO_1	0x10000L
50
51#define ERR(s) write(STDERR_FILENO, s, sizeof(s))
52
53void	moncontrol(int);
54static int hertz(void);
55void	monstartup(u_long lowpc, u_long highpc);
56void	_mcleanup(void);
57
58void
59monstartup(u_long lowpc, u_long highpc)
60{
61	int o;
62	char *cp;
63	struct gmonparam *p = &_gmonparam;
64
65	/*
66	 * round lowpc and highpc to multiples of the density we're using
67	 * so the rest of the scaling (here and in gprof) stays in ints.
68	 */
69	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
70	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
71	p->textsize = p->highpc - p->lowpc;
72	p->kcountsize = p->textsize / HISTFRACTION;
73	p->hashfraction = HASHFRACTION;
74	p->fromssize = p->textsize / p->hashfraction;
75	p->tolimit = p->textsize * ARCDENSITY / 100;
76	if (p->tolimit < MINARCS)
77		p->tolimit = MINARCS;
78	else if (p->tolimit > MAXARCS)
79		p->tolimit = MAXARCS;
80	p->tossize = p->tolimit * sizeof(struct tostruct);
81
82	cp = sbrk(p->kcountsize + p->fromssize + p->tossize);
83	if (cp == (char *)-1) {
84		ERR("monstartup: out of memory\n");
85		return;
86	}
87#ifdef notdef
88	bzero(cp, p->kcountsize + p->fromssize + p->tossize);
89#endif
90	p->tos = (struct tostruct *)cp;
91	cp += p->tossize;
92	p->kcount = (u_short *)cp;
93	cp += p->kcountsize;
94	p->froms = (u_short *)cp;
95
96	minbrk = sbrk(0);
97	p->tos[0].link = 0;
98
99	o = p->highpc - p->lowpc;
100	if (p->kcountsize < o) {
101#ifndef notdef
102		s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
103#else /* avoid floating point */
104		int quot = o / p->kcountsize;
105
106		if (quot >= 0x10000)
107			s_scale = 1;
108		else if (quot >= 0x100)
109			s_scale = 0x10000 / quot;
110		else if (o >= 0x800000)
111			s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
112		else
113			s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
114#endif
115	} else
116		s_scale = SCALE_1_TO_1;
117
118	moncontrol(1);
119}
120
121void
122_mcleanup(void)
123{
124	int fd;
125	int fromindex;
126	int endfrom;
127	u_long frompc;
128	int toindex;
129	struct rawarc rawarc;
130	struct gmonparam *p = &_gmonparam;
131	struct gmonhdr gmonhdr, *hdr;
132	struct clockinfo clockinfo;
133	int mib[2];
134	size_t size;
135	char *profdir;
136	char *proffile;
137	char  buf[PATH_MAX];
138#ifdef DEBUG
139	int log, len;
140	char dbuf[200];
141#endif
142
143	if (p->state == GMON_PROF_ERROR)
144		ERR("_mcleanup: tos overflow\n");
145
146	size = sizeof(clockinfo);
147	mib[0] = CTL_KERN;
148	mib[1] = KERN_CLOCKRATE;
149	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
150		/*
151		 * Best guess
152		 */
153		clockinfo.profhz = hertz();
154	} else if (clockinfo.profhz == 0) {
155		if (clockinfo.hz != 0)
156			clockinfo.profhz = clockinfo.hz;
157		else
158			clockinfo.profhz = hertz();
159	}
160
161	moncontrol(0);
162
163	if (issetugid() == 0 && (profdir = getenv("PROFDIR")) != NULL) {
164		extern char *__progname;
165		char *s, *t, *limit;
166		pid_t pid;
167		long divisor;
168
169		/* If PROFDIR contains a null value, no profiling
170		   output is produced */
171		if (*profdir == '\0') {
172			return;
173		}
174
175		limit = buf + sizeof buf - 1 - 10 - 1 -
176		    strlen(__progname) - 1;
177		t = buf;
178		s = profdir;
179		while((*t = *s) != '\0' && t < limit) {
180			t++;
181			s++;
182		}
183		*t++ = '/';
184
185		/*
186		 * Copy and convert pid from a pid_t to a string.  For
187		 * best performance, divisor should be initialized to
188		 * the largest power of 10 less than PID_MAX.
189		 */
190		pid = getpid();
191		divisor=10000;
192		while (divisor > pid) divisor /= 10;	/* skip leading zeros */
193		do {
194			*t++ = (pid/divisor) + '0';
195			pid %= divisor;
196		} while (divisor /= 10);
197		*t++ = '.';
198
199		s = __progname;
200		while ((*t++ = *s++) != '\0')
201			;
202
203		proffile = buf;
204	} else {
205		proffile = "gmon.out";
206	}
207
208	fd = open(proffile , O_CREAT|O_TRUNC|O_WRONLY, 0664);
209	if (fd < 0) {
210		perror( proffile );
211		return;
212	}
213#ifdef DEBUG
214	log = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
215	if (log < 0) {
216		perror("mcount: gmon.log");
217		return;
218	}
219	snprintf(dbuf, sizeof dbuf, "[mcleanup1] kcount 0x%x ssiz %d\n",
220	    p->kcount, p->kcountsize);
221	write(log, dbuf, strlen(dbuf));
222#endif
223	hdr = (struct gmonhdr *)&gmonhdr;
224	bzero(hdr, sizeof(*hdr));
225	hdr->lpc = p->lowpc;
226	hdr->hpc = p->highpc;
227	hdr->ncnt = p->kcountsize + sizeof(gmonhdr);
228	hdr->version = GMONVERSION;
229	hdr->profrate = clockinfo.profhz;
230	write(fd, (char *)hdr, sizeof *hdr);
231	write(fd, p->kcount, p->kcountsize);
232	endfrom = p->fromssize / sizeof(*p->froms);
233	for (fromindex = 0; fromindex < endfrom; fromindex++) {
234		if (p->froms[fromindex] == 0)
235			continue;
236
237		frompc = p->lowpc;
238		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
239		for (toindex = p->froms[fromindex]; toindex != 0;
240		     toindex = p->tos[toindex].link) {
241#ifdef DEBUG
242			(void) snprintf(dbuf, sizeof dbuf,
243			"[mcleanup2] frompc 0x%x selfpc 0x%x count %d\n" ,
244				frompc, p->tos[toindex].selfpc,
245				p->tos[toindex].count);
246			write(log, dbuf, strlen(dbuf));
247#endif
248			rawarc.raw_frompc = frompc;
249			rawarc.raw_selfpc = p->tos[toindex].selfpc;
250			rawarc.raw_count = p->tos[toindex].count;
251			write(fd, &rawarc, sizeof rawarc);
252		}
253	}
254	close(fd);
255}
256
257/*
258 * Control profiling
259 *	profiling is what mcount checks to see if
260 *	all the data structures are ready.
261 */
262void
263moncontrol(int mode)
264{
265	struct gmonparam *p = &_gmonparam;
266
267	if (mode) {
268		/* start */
269		profil((char *)p->kcount, p->kcountsize, p->lowpc,
270		    s_scale);
271		p->state = GMON_PROF_ON;
272	} else {
273		/* stop */
274		profil((char *)0, 0, 0, 0);
275		p->state = GMON_PROF_OFF;
276	}
277}
278
279/*
280 * discover the tick frequency of the machine
281 * if something goes wrong, we return 0, an impossible hertz.
282 */
283static int
284hertz(void)
285{
286	struct itimerval tim;
287
288	tim.it_interval.tv_sec = 0;
289	tim.it_interval.tv_usec = 1;
290	tim.it_value.tv_sec = 0;
291	tim.it_value.tv_usec = 0;
292	setitimer(ITIMER_REAL, &tim, 0);
293	setitimer(ITIMER_REAL, 0, &tim);
294	if (tim.it_interval.tv_usec < 2)
295		return(0);
296	return (1000000 / tim.it_interval.tv_usec);
297}
298
299
300