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gmon.c revision 1.21
      1 /*	$NetBSD: gmon.c,v 1.21 2003/08/07 16:43:02 agc 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if !defined(lint) && defined(LIBC_SCCS)
     34 #if 0
     35 static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: gmon.c,v 1.21 2003/08/07 16:43:02 agc Exp $");
     38 #endif
     39 #endif
     40 
     41 #include "namespace.h"
     42 #include <sys/param.h>
     43 #include <sys/time.h>
     44 #include <sys/gmon.h>
     45 #include <sys/sysctl.h>
     46 
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <fcntl.h>
     50 #include <limits.h>
     51 #include <unistd.h>
     52 #include <err.h>
     53 #include "extern.h"
     54 
     55 struct gmonparam _gmonparam = { GMON_PROF_OFF };
     56 
     57 static u_int	s_scale;
     58 /* see profil(2) where this is describe (incorrectly) */
     59 #define		SCALE_1_TO_1	0x10000L
     60 
     61 #define ERR(s) write(STDERR_FILENO, s, sizeof(s))
     62 
     63 void	moncontrol __P((int));
     64 void	monstartup __P((u_long, u_long));
     65 void	_mcleanup __P((void));
     66 static int hertz __P((void));
     67 
     68 
     69 void
     70 monstartup(lowpc, highpc)
     71 	u_long lowpc;
     72 	u_long highpc;
     73 {
     74 	u_long o;
     75 	char *cp;
     76 	struct gmonparam *p = &_gmonparam;
     77 
     78 	/*
     79 	 * round lowpc and highpc to multiples of the density we're using
     80 	 * so the rest of the scaling (here and in gprof) stays in ints.
     81 	 */
     82 	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
     83 	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
     84 	p->textsize = p->highpc - p->lowpc;
     85 	p->kcountsize = p->textsize / HISTFRACTION;
     86 	p->hashfraction = HASHFRACTION;
     87 	p->fromssize = p->textsize / p->hashfraction;
     88 	p->tolimit = p->textsize * ARCDENSITY / 100;
     89 	if (p->tolimit < MINARCS)
     90 		p->tolimit = MINARCS;
     91 	else if (p->tolimit > MAXARCS)
     92 		p->tolimit = MAXARCS;
     93 	p->tossize = p->tolimit * sizeof(struct tostruct);
     94 
     95 	cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
     96 	if (cp == (char *)-1) {
     97 		ERR("monstartup: out of memory\n");
     98 		return;
     99 	}
    100 #ifdef notdef
    101 	memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
    102 #endif
    103 	p->tos = (struct tostruct *)(void *)cp;
    104 	cp += (size_t)p->tossize;
    105 	p->kcount = (u_short *)(void *)cp;
    106 	cp += (size_t)p->kcountsize;
    107 	p->froms = (u_short *)(void *)cp;
    108 
    109 	__minbrk = sbrk((intptr_t)0);
    110 	p->tos[0].link = 0;
    111 
    112 	o = p->highpc - p->lowpc;
    113 	if (p->kcountsize < o) {
    114 #ifndef notdef
    115 		s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
    116 #else /* avoid floating point */
    117 		u_long quot = o / p->kcountsize;
    118 
    119 		if (quot >= 0x10000)
    120 			s_scale = 1;
    121 		else if (quot >= 0x100)
    122 			s_scale = 0x10000 / quot;
    123 		else if (o >= 0x800000)
    124 			s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
    125 		else
    126 			s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
    127 #endif
    128 	} else
    129 		s_scale = SCALE_1_TO_1;
    130 
    131 	moncontrol(1);
    132 }
    133 
    134 void
    135 _mcleanup()
    136 {
    137 	int fd;
    138 	int fromindex;
    139 	int endfrom;
    140 	u_long frompc;
    141 	int toindex;
    142 	struct rawarc rawarc;
    143 	struct gmonparam *p = &_gmonparam;
    144 	struct gmonhdr gmonhdr, *hdr;
    145 	struct clockinfo clockinfo;
    146 	int mib[2];
    147 	size_t size;
    148 	char *profdir;
    149 	char *proffile;
    150 	char  buf[PATH_MAX];
    151 #ifdef DEBUG
    152 	int log, len;
    153 	char buf2[200];
    154 #endif
    155 
    156 	/*
    157 	 * We disallow writing to the profiling file, if we are a
    158 	 * set{u,g}id program and our effective {u,g}id does not match
    159 	 * our real one.
    160 	 */
    161 	if (issetugid() && (geteuid() != getuid() || getegid() != getgid())) {
    162 		warnx("mcount: Profiling of set{u,g}id binaries is not"
    163 		    " allowed");
    164 		return;
    165 	}
    166 
    167 	if (p->state == GMON_PROF_ERROR)
    168 		ERR("_mcleanup: tos overflow\n");
    169 
    170 	size = sizeof(clockinfo);
    171 	mib[0] = CTL_KERN;
    172 	mib[1] = KERN_CLOCKRATE;
    173 	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
    174 		/*
    175 		 * Best guess
    176 		 */
    177 		clockinfo.profhz = hertz();
    178 	} else if (clockinfo.profhz == 0) {
    179 		if (clockinfo.hz != 0)
    180 			clockinfo.profhz = clockinfo.hz;
    181 		else
    182 			clockinfo.profhz = hertz();
    183 	}
    184 
    185 	moncontrol(0);
    186 
    187 	if ((profdir = getenv("PROFDIR")) != NULL) {
    188 		/* If PROFDIR contains a null value, no profiling
    189 		   output is produced */
    190 		if (*profdir == '\0')
    191 			return;
    192 
    193 		if (snprintf(buf, sizeof buf, "%s/%d.%s",
    194 			    profdir, getpid(), getprogname()) >= sizeof buf) {
    195 			warnx("_mcleanup: internal buffer overflow, PROFDIR too long");
    196 			return;
    197 		}
    198 
    199 		proffile = buf;
    200 	} else {
    201 		proffile = "gmon.out";
    202 	}
    203 
    204 	fd = open(proffile , O_CREAT|O_TRUNC|O_WRONLY, 0666);
    205 	if (fd < 0) {
    206 		warn("mcount: Cannot open `%s'", proffile);
    207 		return;
    208 	}
    209 #ifdef DEBUG
    210 	log = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
    211 	if (log < 0) {
    212 		warn("mcount: Cannot open `gmon.log'");
    213 		return;
    214 	}
    215 	len = snprintf(buf2, sizeof buf2, "[mcleanup1] kcount 0x%x ssiz %d\n",
    216 	    p->kcount, p->kcountsize);
    217 	write(log, buf2, len);
    218 #endif
    219 	hdr = (struct gmonhdr *)&gmonhdr;
    220 	hdr->lpc = p->lowpc;
    221 	hdr->hpc = p->highpc;
    222 	hdr->ncnt = (int)(p->kcountsize + sizeof(gmonhdr));
    223 	hdr->version = GMONVERSION;
    224 	hdr->profrate = clockinfo.profhz;
    225 	(void)write(fd, hdr, sizeof *hdr);
    226 	(void)write(fd, p->kcount, (size_t)p->kcountsize);
    227 	endfrom = (int)(p->fromssize / sizeof(*p->froms));
    228 	for (fromindex = 0; fromindex < endfrom; fromindex++) {
    229 		if (p->froms[fromindex] == 0)
    230 			continue;
    231 
    232 		frompc = p->lowpc;
    233 		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
    234 		for (toindex = p->froms[fromindex]; toindex != 0;
    235 		     toindex = p->tos[toindex].link) {
    236 #ifdef DEBUG
    237 			len = snprintf(buf2, sizeof buf2,
    238 			"[mcleanup2] frompc 0x%x selfpc 0x%x count %d\n" ,
    239 				frompc, p->tos[toindex].selfpc,
    240 				p->tos[toindex].count);
    241 			write(log, buf2, len);
    242 #endif
    243 			rawarc.raw_frompc = frompc;
    244 			rawarc.raw_selfpc = p->tos[toindex].selfpc;
    245 			rawarc.raw_count = p->tos[toindex].count;
    246 			write(fd, &rawarc, sizeof rawarc);
    247 		}
    248 	}
    249 	close(fd);
    250 }
    251 
    252 /*
    253  * Control profiling
    254  *	profiling is what mcount checks to see if
    255  *	all the data structures are ready.
    256  */
    257 void
    258 moncontrol(mode)
    259 	int mode;
    260 {
    261 	struct gmonparam *p = &_gmonparam;
    262 
    263 	if (mode) {
    264 		/* start */
    265 		profil((char *)(void *)p->kcount, (size_t)p->kcountsize,
    266 		    p->lowpc, s_scale);
    267 		p->state = GMON_PROF_ON;
    268 	} else {
    269 		/* stop */
    270 		profil(NULL, 0, (u_long)0, 0);
    271 		p->state = GMON_PROF_OFF;
    272 	}
    273 }
    274 
    275 /*
    276  * discover the tick frequency of the machine
    277  * if something goes wrong, we return 0, an impossible hertz.
    278  */
    279 static int
    280 hertz()
    281 {
    282 	struct itimerval tim;
    283 
    284 	tim.it_interval.tv_sec = 0;
    285 	tim.it_interval.tv_usec = 1;
    286 	tim.it_value.tv_sec = 0;
    287 	tim.it_value.tv_usec = 0;
    288 	setitimer(ITIMER_REAL, &tim, 0);
    289 	setitimer(ITIMER_REAL, 0, &tim);
    290 	if (tim.it_interval.tv_usec < 2)
    291 		return(0);
    292 	return (int)(1000000 / tim.it_interval.tv_usec);
    293 }
    294