xref: /freebsd/lib/libc/gmon/gmon.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
1 /*-
2  * Copyright (c) 1983, 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
32 #endif
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "namespace.h"
37 #include <sys/param.h>
38 #include <sys/time.h>
39 #include <sys/gmon.h>
40 #include <sys/mman.h>
41 #include <sys/sysctl.h>
42 
43 #include <err.h>
44 #include <fcntl.h>
45 #include <inttypes.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 #include "un-namespace.h"
51 
52 #include "libc_private.h"
53 
54 struct gmonparam _gmonparam = { GMON_PROF_OFF };
55 
56 static int	s_scale;
57 /* See profil(2) where this is described (incorrectly). */
58 #define	SCALE_SHIFT	16
59 
60 #define ERR(s) _write(2, s, sizeof(s))
61 
62 void	moncontrol(int);
63 static int hertz(void);
64 void	_mcleanup(void);
65 
66 void
67 monstartup(u_long lowpc, u_long highpc)
68 {
69 	int o;
70 	char *cp;
71 	struct gmonparam *p = &_gmonparam;
72 
73 	/*
74 	 * round lowpc and highpc to multiples of the density we're using
75 	 * so the rest of the scaling (here and in gprof) stays in ints.
76 	 */
77 	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
78 	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
79 	p->textsize = p->highpc - p->lowpc;
80 	p->kcountsize = p->textsize / HISTFRACTION;
81 	p->hashfraction = HASHFRACTION;
82 	p->fromssize = p->textsize / HASHFRACTION;
83 	p->tolimit = p->textsize * ARCDENSITY / 100;
84 	if (p->tolimit < MINARCS)
85 		p->tolimit = MINARCS;
86 	else if (p->tolimit > MAXARCS)
87 		p->tolimit = MAXARCS;
88 	p->tossize = p->tolimit * sizeof(struct tostruct);
89 
90 	cp = mmap(NULL, p->kcountsize + p->fromssize + p->tossize,
91 	    PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
92 	if (cp == MAP_FAILED) {
93 		ERR("monstartup: out of memory\n");
94 		return;
95 	}
96 #ifdef notdef
97 	bzero(cp, p->kcountsize + p->fromssize + p->tossize);
98 #endif
99 	p->tos = (struct tostruct *)cp;
100 	cp += p->tossize;
101 	p->kcount = (u_short *)cp;
102 	cp += p->kcountsize;
103 	p->froms = (u_short *)cp;
104 
105 	p->tos[0].link = 0;
106 
107 	o = p->highpc - p->lowpc;
108 	s_scale = (p->kcountsize < o) ?
109 	    ((uintmax_t)p->kcountsize << SCALE_SHIFT) / o : (1 << SCALE_SHIFT);
110 	moncontrol(1);
111 }
112 
113 void
114 _mcleanup(void)
115 {
116 	int fd;
117 	int fromindex;
118 	int endfrom;
119 	u_long frompc;
120 	int toindex;
121 	struct rawarc rawarc;
122 	struct gmonparam *p = &_gmonparam;
123 	struct gmonhdr gmonhdr, *hdr;
124 	struct clockinfo clockinfo;
125 	char outname[128];
126 	int mib[2];
127 	size_t size;
128 #ifdef DEBUG
129 	int log, len;
130 	char buf[200];
131 #endif
132 
133 	if (p->state == GMON_PROF_ERROR)
134 		ERR("_mcleanup: tos overflow\n");
135 
136 	size = sizeof(clockinfo);
137 	mib[0] = CTL_KERN;
138 	mib[1] = KERN_CLOCKRATE;
139 	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
140 		/*
141 		 * Best guess
142 		 */
143 		clockinfo.profhz = hertz();
144 	} else if (clockinfo.profhz == 0) {
145 		if (clockinfo.hz != 0)
146 			clockinfo.profhz = clockinfo.hz;
147 		else
148 			clockinfo.profhz = hertz();
149 	}
150 
151 	moncontrol(0);
152 	if (getenv("PROFIL_USE_PID"))
153 		snprintf(outname, sizeof(outname), "%s.%d.gmon",
154 		    _getprogname(), getpid());
155 	else
156 		snprintf(outname, sizeof(outname), "%s.gmon", _getprogname());
157 
158 	fd = _open(outname, O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0666);
159 	if (fd < 0) {
160 		_warn("_mcleanup: %s", outname);
161 		return;
162 	}
163 #ifdef DEBUG
164 	log = _open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0664);
165 	if (log < 0) {
166 		_warn("_mcleanup: gmon.log");
167 		return;
168 	}
169 	len = sprintf(buf, "[mcleanup1] kcount 0x%p ssiz %lu\n",
170 	    p->kcount, p->kcountsize);
171 	_write(log, buf, len);
172 #endif
173 	hdr = (struct gmonhdr *)&gmonhdr;
174 	bzero(hdr, sizeof(*hdr));
175 	hdr->lpc = p->lowpc;
176 	hdr->hpc = p->highpc;
177 	hdr->ncnt = p->kcountsize + sizeof(gmonhdr);
178 	hdr->version = GMONVERSION;
179 	hdr->profrate = clockinfo.profhz;
180 	_write(fd, (char *)hdr, sizeof *hdr);
181 	_write(fd, p->kcount, p->kcountsize);
182 	endfrom = p->fromssize / sizeof(*p->froms);
183 	for (fromindex = 0; fromindex < endfrom; fromindex++) {
184 		if (p->froms[fromindex] == 0)
185 			continue;
186 
187 		frompc = p->lowpc;
188 		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
189 		for (toindex = p->froms[fromindex]; toindex != 0;
190 		     toindex = p->tos[toindex].link) {
191 #ifdef DEBUG
192 			len = sprintf(buf,
193 			"[mcleanup2] frompc 0x%lx selfpc 0x%lx count %lu\n" ,
194 				frompc, p->tos[toindex].selfpc,
195 				p->tos[toindex].count);
196 			_write(log, buf, len);
197 #endif
198 			rawarc.raw_frompc = frompc;
199 			rawarc.raw_selfpc = p->tos[toindex].selfpc;
200 			rawarc.raw_count = p->tos[toindex].count;
201 			_write(fd, &rawarc, sizeof rawarc);
202 		}
203 	}
204 	_close(fd);
205 }
206 
207 /*
208  * Control profiling
209  *	profiling is what mcount checks to see if
210  *	all the data structures are ready.
211  */
212 void
213 moncontrol(int mode)
214 {
215 	struct gmonparam *p = &_gmonparam;
216 
217 	if (mode) {
218 		/* start */
219 		profil((char *)p->kcount, p->kcountsize, p->lowpc, s_scale);
220 		p->state = GMON_PROF_ON;
221 	} else {
222 		/* stop */
223 		profil((char *)0, 0, 0, 0);
224 		p->state = GMON_PROF_OFF;
225 	}
226 }
227 
228 /*
229  * discover the tick frequency of the machine
230  * if something goes wrong, we return 0, an impossible hertz.
231  */
232 static int
233 hertz(void)
234 {
235 	struct itimerval tim;
236 
237 	tim.it_interval.tv_sec = 0;
238 	tim.it_interval.tv_usec = 1;
239 	tim.it_value.tv_sec = 0;
240 	tim.it_value.tv_usec = 0;
241 	setitimer(ITIMER_REAL, &tim, 0);
242 	setitimer(ITIMER_REAL, 0, &tim);
243 	if (tim.it_interval.tv_usec < 2)
244 		return(0);
245 	return (1000000 / tim.it_interval.tv_usec);
246 }
247