xref: /freebsd/lib/libc/gmon/gmon.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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 "namespace.h"
33 #include <sys/param.h>
34 #include <sys/time.h>
35 #include <sys/gmon.h>
36 #include <sys/mman.h>
37 #include <sys/sysctl.h>
38 
39 #include <err.h>
40 #include <fcntl.h>
41 #include <inttypes.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include "un-namespace.h"
47 
48 #include "libc_private.h"
49 
50 struct gmonparam _gmonparam = { GMON_PROF_OFF };
51 
52 static int	s_scale;
53 /* See profil(2) where this is described (incorrectly). */
54 #define	SCALE_SHIFT	16
55 
56 #define ERR(s) _write(2, s, sizeof(s))
57 
58 void	moncontrol(int);
59 static int hertz(void);
60 void	_mcleanup(void);
61 
62 void
63 monstartup(u_long lowpc, u_long highpc)
64 {
65 	int o;
66 	char *cp;
67 	struct gmonparam *p = &_gmonparam;
68 
69 	/*
70 	 * round lowpc and highpc to multiples of the density we're using
71 	 * so the rest of the scaling (here and in gprof) stays in ints.
72 	 */
73 	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
74 	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
75 	p->textsize = p->highpc - p->lowpc;
76 	p->kcountsize = p->textsize / HISTFRACTION;
77 	p->hashfraction = HASHFRACTION;
78 	p->fromssize = p->textsize / HASHFRACTION;
79 	p->tolimit = p->textsize * ARCDENSITY / 100;
80 	if (p->tolimit < MINARCS)
81 		p->tolimit = MINARCS;
82 	else if (p->tolimit > MAXARCS)
83 		p->tolimit = MAXARCS;
84 	p->tossize = p->tolimit * sizeof(struct tostruct);
85 
86 	cp = mmap(NULL, p->kcountsize + p->fromssize + p->tossize,
87 	    PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
88 	if (cp == MAP_FAILED) {
89 		ERR("monstartup: out of memory\n");
90 		return;
91 	}
92 #ifdef notdef
93 	bzero(cp, p->kcountsize + p->fromssize + p->tossize);
94 #endif
95 	p->tos = (struct tostruct *)cp;
96 	cp += p->tossize;
97 	p->kcount = (u_short *)cp;
98 	cp += p->kcountsize;
99 	p->froms = (u_short *)cp;
100 
101 	p->tos[0].link = 0;
102 
103 	o = p->highpc - p->lowpc;
104 	s_scale = (p->kcountsize < o) ?
105 	    ((uintmax_t)p->kcountsize << SCALE_SHIFT) / o : (1 << SCALE_SHIFT);
106 	moncontrol(1);
107 }
108 
109 void
110 _mcleanup(void)
111 {
112 	int fd;
113 	int fromindex;
114 	int endfrom;
115 	u_long frompc;
116 	int toindex;
117 	struct rawarc rawarc;
118 	struct gmonparam *p = &_gmonparam;
119 	struct gmonhdr gmonhdr, *hdr;
120 	struct clockinfo clockinfo;
121 	char outname[128];
122 	int mib[2];
123 	size_t size;
124 #ifdef DEBUG
125 	int log, len;
126 	char buf[200];
127 #endif
128 
129 	if (p->state == GMON_PROF_ERROR)
130 		ERR("_mcleanup: tos overflow\n");
131 
132 	size = sizeof(clockinfo);
133 	mib[0] = CTL_KERN;
134 	mib[1] = KERN_CLOCKRATE;
135 	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
136 		/*
137 		 * Best guess
138 		 */
139 		clockinfo.profhz = hertz();
140 	} else if (clockinfo.profhz == 0) {
141 		if (clockinfo.hz != 0)
142 			clockinfo.profhz = clockinfo.hz;
143 		else
144 			clockinfo.profhz = hertz();
145 	}
146 
147 	moncontrol(0);
148 	if (getenv("PROFIL_USE_PID"))
149 		snprintf(outname, sizeof(outname), "%s.%d.gmon",
150 		    _getprogname(), getpid());
151 	else
152 		snprintf(outname, sizeof(outname), "%s.gmon", _getprogname());
153 
154 	fd = _open(outname, O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0666);
155 	if (fd < 0) {
156 		_warn("_mcleanup: %s", outname);
157 		return;
158 	}
159 #ifdef DEBUG
160 	log = _open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0664);
161 	if (log < 0) {
162 		_warn("_mcleanup: gmon.log");
163 		return;
164 	}
165 	len = sprintf(buf, "[mcleanup1] kcount 0x%p ssiz %lu\n",
166 	    p->kcount, p->kcountsize);
167 	_write(log, buf, len);
168 #endif
169 	hdr = (struct gmonhdr *)&gmonhdr;
170 	bzero(hdr, sizeof(*hdr));
171 	hdr->lpc = p->lowpc;
172 	hdr->hpc = p->highpc;
173 	hdr->ncnt = p->kcountsize + sizeof(gmonhdr);
174 	hdr->version = GMONVERSION;
175 	hdr->profrate = clockinfo.profhz;
176 	_write(fd, (char *)hdr, sizeof *hdr);
177 	_write(fd, p->kcount, p->kcountsize);
178 	endfrom = p->fromssize / sizeof(*p->froms);
179 	for (fromindex = 0; fromindex < endfrom; fromindex++) {
180 		if (p->froms[fromindex] == 0)
181 			continue;
182 
183 		frompc = p->lowpc;
184 		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
185 		for (toindex = p->froms[fromindex]; toindex != 0;
186 		     toindex = p->tos[toindex].link) {
187 #ifdef DEBUG
188 			len = sprintf(buf,
189 			"[mcleanup2] frompc 0x%lx selfpc 0x%lx count %lu\n" ,
190 				frompc, p->tos[toindex].selfpc,
191 				p->tos[toindex].count);
192 			_write(log, buf, len);
193 #endif
194 			rawarc.raw_frompc = frompc;
195 			rawarc.raw_selfpc = p->tos[toindex].selfpc;
196 			rawarc.raw_count = p->tos[toindex].count;
197 			_write(fd, &rawarc, sizeof rawarc);
198 		}
199 	}
200 	_close(fd);
201 }
202 
203 /*
204  * Control profiling
205  *	profiling is what mcount checks to see if
206  *	all the data structures are ready.
207  */
208 void
209 moncontrol(int mode)
210 {
211 	struct gmonparam *p = &_gmonparam;
212 
213 	if (mode) {
214 		/* start */
215 		profil((char *)p->kcount, p->kcountsize, p->lowpc, s_scale);
216 		p->state = GMON_PROF_ON;
217 	} else {
218 		/* stop */
219 		profil((char *)0, 0, 0, 0);
220 		p->state = GMON_PROF_OFF;
221 	}
222 }
223 
224 /*
225  * discover the tick frequency of the machine
226  * if something goes wrong, we return 0, an impossible hertz.
227  */
228 static int
229 hertz(void)
230 {
231 	struct itimerval tim;
232 
233 	tim.it_interval.tv_sec = 0;
234 	tim.it_interval.tv_usec = 1;
235 	tim.it_value.tv_sec = 0;
236 	tim.it_value.tv_usec = 0;
237 	setitimer(ITIMER_REAL, &tim, 0);
238 	setitimer(ITIMER_REAL, 0, &tim);
239 	if (tim.it_interval.tv_usec < 2)
240 		return(0);
241 	return (1000000 / tim.it_interval.tv_usec);
242 }
243