xref: /src/lib/libc/gmon/gmon.c

/*	$NetBSD: gmon.c,v 1.21 2003/08/07 16:43:02 agc Exp $	*/

/*-
 * Copyright (c) 1983, 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if !defined(lint) && defined(LIBC_SCCS)
#if 0
static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: gmon.c,v 1.21 2003/08/07 16:43:02 agc Exp $");
#endif
#endif

#include "namespace.h"
#include <sys/param.h>
#include <sys/time.h>
#include <sys/gmon.h>
#include <sys/sysctl.h>

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <err.h>
#include "extern.h"

struct gmonparam _gmonparam = { GMON_PROF_OFF };

static u_int	s_scale;
/* see profil(2) where this is describe (incorrectly) */
#define		SCALE_1_TO_1	0x10000L

#define ERR(s) write(STDERR_FILENO, s, sizeof(s))

void	moncontrol __P((int));
void	monstartup __P((u_long, u_long));
void	_mcleanup __P((void));
static int hertz __P((void));


void
monstartup(lowpc, highpc)
	u_long lowpc;
	u_long highpc;
{
	u_long o;
	char *cp;
	struct gmonparam *p = &_gmonparam;

	/*
	 * round lowpc and highpc to multiples of the density we're using
	 * so the rest of the scaling (here and in gprof) stays in ints.
	 */
	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
	p->textsize = p->highpc - p->lowpc;
	p->kcountsize = p->textsize / HISTFRACTION;
	p->hashfraction = HASHFRACTION;
	p->fromssize = p->textsize / p->hashfraction;
	p->tolimit = p->textsize * ARCDENSITY / 100;
	if (p->tolimit < MINARCS)
		p->tolimit = MINARCS;
	else if (p->tolimit > MAXARCS)
		p->tolimit = MAXARCS;
	p->tossize = p->tolimit * sizeof(struct tostruct);

	cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
	if (cp == (char *)-1) {
		ERR("monstartup: out of memory\n");
		return;
	}
#ifdef notdef
	memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
#endif
	p->tos = (struct tostruct *)(void *)cp;
	cp += (size_t)p->tossize;
	p->kcount = (u_short *)(void *)cp;
	cp += (size_t)p->kcountsize;
	p->froms = (u_short *)(void *)cp;

	__minbrk = sbrk((intptr_t)0);
	p->tos[0].link = 0;

	o = p->highpc - p->lowpc;
	if (p->kcountsize < o) {
#ifndef notdef
		s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
#else /* avoid floating point */
		u_long quot = o / p->kcountsize;

		if (quot >= 0x10000)
			s_scale = 1;
		else if (quot >= 0x100)
			s_scale = 0x10000 / quot;
		else if (o >= 0x800000)
			s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
		else
			s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
#endif
	} else
		s_scale = SCALE_1_TO_1;

	moncontrol(1);
}

void
_mcleanup()
{
	int fd;
	int fromindex;
	int endfrom;
	u_long frompc;
	int toindex;
	struct rawarc rawarc;
	struct gmonparam *p = &_gmonparam;
	struct gmonhdr gmonhdr, *hdr;
	struct clockinfo clockinfo;
	int mib[2];
	size_t size;
	char *profdir;
	char *proffile;
	char  buf[PATH_MAX];
#ifdef DEBUG
	int log, len;
	char buf2[200];
#endif

	/*
	 * We disallow writing to the profiling file, if we are a
	 * set{u,g}id program and our effective {u,g}id does not match
	 * our real one.
	 */
	if (issetugid() && (geteuid() != getuid() || getegid() != getgid())) {
		warnx("mcount: Profiling of set{u,g}id binaries is not"
		    " allowed");
		return;
	}

	if (p->state == GMON_PROF_ERROR)
		ERR("_mcleanup: tos overflow\n");

	size = sizeof(clockinfo);
	mib[0] = CTL_KERN;
	mib[1] = KERN_CLOCKRATE;
	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
		/*
		 * Best guess
		 */
		clockinfo.profhz = hertz();
	} else if (clockinfo.profhz == 0) {
		if (clockinfo.hz != 0)
			clockinfo.profhz = clockinfo.hz;
		else
			clockinfo.profhz = hertz();
	}

	moncontrol(0);

	if ((profdir = getenv("PROFDIR")) != NULL) {
		/* If PROFDIR contains a null value, no profiling
		   output is produced */
		if (*profdir == '\0')
			return;

		if (snprintf(buf, sizeof buf, "%s/%d.%s",
			    profdir, getpid(), getprogname()) >= sizeof buf) {
			warnx("_mcleanup: internal buffer overflow, PROFDIR too long");
			return;
		}

		proffile = buf;
	} else {
		proffile = "gmon.out";
	}

	fd = open(proffile , O_CREAT|O_TRUNC|O_WRONLY, 0666);
	if (fd < 0) {
		warn("mcount: Cannot open `%s'", proffile);
		return;
	}
#ifdef DEBUG
	log = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
	if (log < 0) {
		warn("mcount: Cannot open `gmon.log'");
		return;
	}
	len = snprintf(buf2, sizeof buf2, "[mcleanup1] kcount 0x%x ssiz %d\n",
	    p->kcount, p->kcountsize);
	write(log, buf2, len);
#endif
	hdr = (struct gmonhdr *)&gmonhdr;
	hdr->lpc = p->lowpc;
	hdr->hpc = p->highpc;
	hdr->ncnt = (int)(p->kcountsize + sizeof(gmonhdr));
	hdr->version = GMONVERSION;
	hdr->profrate = clockinfo.profhz;
	(void)write(fd, hdr, sizeof *hdr);
	(void)write(fd, p->kcount, (size_t)p->kcountsize);
	endfrom = (int)(p->fromssize / sizeof(*p->froms));
	for (fromindex = 0; fromindex < endfrom; fromindex++) {
		if (p->froms[fromindex] == 0)
			continue;

		frompc = p->lowpc;
		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
		for (toindex = p->froms[fromindex]; toindex != 0;
		     toindex = p->tos[toindex].link) {
#ifdef DEBUG
			len = snprintf(buf2, sizeof buf2,
			"[mcleanup2] frompc 0x%x selfpc 0x%x count %d\n" ,
				frompc, p->tos[toindex].selfpc,
				p->tos[toindex].count);
			write(log, buf2, len);
#endif
			rawarc.raw_frompc = frompc;
			rawarc.raw_selfpc = p->tos[toindex].selfpc;
			rawarc.raw_count = p->tos[toindex].count;
			write(fd, &rawarc, sizeof rawarc);
		}
	}
	close(fd);
}

/*
 * Control profiling
 *	profiling is what mcount checks to see if
 *	all the data structures are ready.
 */
void
moncontrol(mode)
	int mode;
{
	struct gmonparam *p = &_gmonparam;

	if (mode) {
		/* start */
		profil((char *)(void *)p->kcount, (size_t)p->kcountsize,
		    p->lowpc, s_scale);
		p->state = GMON_PROF_ON;
	} else {
		/* stop */
		profil(NULL, 0, (u_long)0, 0);
		p->state = GMON_PROF_OFF;
	}
}

/*
 * discover the tick frequency of the machine
 * if something goes wrong, we return 0, an impossible hertz.
 */
static int
hertz()
{
	struct itimerval tim;

	tim.it_interval.tv_sec = 0;
	tim.it_interval.tv_usec = 1;
	tim.it_value.tv_sec = 0;
	tim.it_value.tv_usec = 0;
	setitimer(ITIMER_REAL, &tim, 0);
	setitimer(ITIMER_REAL, 0, &tim);
	if (tim.it_interval.tv_usec < 2)
		return(0);
	return (int)(1000000 / tim.it_interval.tv_usec);
}