gmon.c revision 1.36 1 /* $NetBSD: gmon.c,v 1.36 2021/07/03 14:08:55 christos Exp $ */
2
3 /*
4 * Copyright (c) 2003, 2004 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Nathan J. Williams for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed for the NetBSD Project by
20 * Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 * or promote products derived from this software without specific prior
23 * written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38 /*-
39 * Copyright (c) 1983, 1992, 1993
40 * The Regents of the University of California. All rights reserved.
41 *
42 * Redistribution and use in source and binary forms, with or without
43 * modification, are permitted provided that the following conditions
44 * are met:
45 * 1. Redistributions of source code must retain the above copyright
46 * notice, this list of conditions and the following disclaimer.
47 * 2. Redistributions in binary form must reproduce the above copyright
48 * notice, this list of conditions and the following disclaimer in the
49 * documentation and/or other materials provided with the distribution.
50 * 3. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * SUCH DAMAGE.
65 */
66
67 #include <sys/cdefs.h>
68 #if !defined(lint) && defined(LIBC_SCCS)
69 #if 0
70 static char sccsid[] = "@(#)gmon.c 8.1 (Berkeley) 6/4/93";
71 #else
72 __RCSID("$NetBSD: gmon.c,v 1.36 2021/07/03 14:08:55 christos Exp $");
73 #endif
74 #endif
75
76 #include "namespace.h"
77 #include <sys/param.h>
78 #include <sys/time.h>
79 #include <sys/gmon.h>
80 #include <sys/mman.h>
81 #include <sys/sysctl.h>
82
83 #include <stdio.h>
84 #include <stdlib.h>
85 #include <string.h>
86 #include <fcntl.h>
87 #include <limits.h>
88 #include <unistd.h>
89 #include <err.h>
90 #include "extern.h"
91 #include "reentrant.h"
92
93 struct gmonparam _gmonparam = { .state = GMON_PROF_OFF };
94
95 #ifdef _REENTRANT
96 struct gmonparam *_gmonfree;
97 struct gmonparam *_gmoninuse;
98 mutex_t _gmonlock = MUTEX_INITIALIZER;
99 thread_key_t _gmonkey;
100 struct gmonparam _gmondummy;
101 #endif
102
103 static u_int s_scale;
104 /* see profil(2) where this is describe (incorrectly) */
105 #define SCALE_1_TO_1 0x10000L
106
107 void moncontrol(int);
108 void monstartup(u_long, u_long);
109 void _mcleanup(void);
110 static int hertz(void);
111
112 #ifdef _REENTRANT
113 static void _m_gmon_destructor(void *);
114 struct gmonparam *_m_gmon_alloc(void)
115 __attribute__((__no_instrument_function__));
116 static void _m_gmon_merge(void);
117 static void _m_gmon_merge_two(struct gmonparam *, struct gmonparam *);
118 #endif
119
120 void
121 monstartup(u_long lowpc, u_long highpc)
122 {
123 u_long o;
124 char *cp;
125 struct gmonparam *p = &_gmonparam;
126
127 /*
128 * round lowpc and highpc to multiples of the density we're using
129 * so the rest of the scaling (here and in gprof) stays in ints.
130 */
131 p->lowpc = rounddown(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
132 p->highpc = roundup(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
133 p->textsize = p->highpc - p->lowpc;
134 p->kcountsize = p->textsize / HISTFRACTION;
135 p->hashfraction = HASHFRACTION;
136 p->fromssize = p->textsize / p->hashfraction;
137 p->tolimit = p->textsize * ARCDENSITY / 100;
138 if (p->tolimit < MINARCS)
139 p->tolimit = MINARCS;
140 else if (p->tolimit > MAXARCS)
141 p->tolimit = MAXARCS;
142 p->tossize = p->tolimit * sizeof(struct tostruct);
143
144 cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
145 if (cp == (char *)-1) {
146 warnx("%s: out of memory", __func__);
147 return;
148 }
149 #ifdef notdef
150 (void)memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
151 #endif
152 p->tos = (struct tostruct *)(void *)cp;
153 cp += (size_t)p->tossize;
154 p->kcount = (u_short *)(void *)cp;
155 cp += (size_t)p->kcountsize;
156 p->froms = (u_short *)(void *)cp;
157
158 __minbrk = sbrk((intptr_t)0);
159 p->tos[0].link = 0;
160
161 o = p->highpc - p->lowpc;
162 if (p->kcountsize < o) {
163 #ifndef notdef
164 s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
165 #else /* avoid floating point */
166 u_long quot = o / p->kcountsize;
167
168 if (quot >= 0x10000)
169 s_scale = 1;
170 else if (quot >= 0x100)
171 s_scale = 0x10000 / quot;
172 else if (o >= 0x800000)
173 s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
174 else
175 s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
176 #endif
177 } else
178 s_scale = SCALE_1_TO_1;
179
180 #ifdef _REENTRANT
181 _gmondummy.state = GMON_PROF_BUSY;
182 thr_keycreate(&_gmonkey, _m_gmon_destructor);
183 #endif
184 moncontrol(1);
185 }
186
187 #ifdef _REENTRANT
188 static void
189 _m_gmon_destructor(void *arg)
190 {
191 struct gmonparam *p = arg, *q, **prev;
192
193 if (p == &_gmondummy)
194 return;
195
196 thr_setspecific(_gmonkey, &_gmondummy);
197
198 mutex_lock(&_gmonlock);
199 /* XXX eww, linear list traversal. */
200 for (q = _gmoninuse, prev = &_gmoninuse;
201 q != NULL;
202 prev = (struct gmonparam **)(void *)&q->kcount, /* XXX */
203 q = (struct gmonparam *)(void *)q->kcount) {
204 if (q == p)
205 *prev = (struct gmonparam *)(void *)q->kcount;
206 }
207 p->kcount = (u_short *)(void *)_gmonfree;
208 _gmonfree = p;
209 mutex_unlock(&_gmonlock);
210
211 thr_setspecific(_gmonkey, NULL);
212 }
213
214 struct gmonparam *
215 _m_gmon_alloc(void)
216 {
217 struct gmonparam *p;
218 char *cp;
219
220 mutex_lock(&_gmonlock);
221 if (_gmonfree != NULL) {
222 p = _gmonfree;
223 _gmonfree = (struct gmonparam *)(void *)p->kcount;
224 p->kcount = (u_short *)(void *)_gmoninuse;
225 _gmoninuse = p;
226 } else {
227 mutex_unlock(&_gmonlock);
228 cp = mmap(NULL,
229 (size_t)(sizeof (struct gmonparam) +
230 _gmonparam.fromssize + _gmonparam.tossize),
231 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, (off_t)0);
232 p = (void *)cp;
233 *p = _gmonparam;
234 p->state = GMON_PROF_ON;
235 p->kcount = NULL;
236 cp += sizeof (struct gmonparam);
237 memset(cp, 0, (size_t)(p->fromssize + p->tossize));
238 p->froms = (u_short *)(void *)cp;
239 p->tos = (struct tostruct *)(void *)(cp + p->fromssize);
240 mutex_lock(&_gmonlock);
241 p->kcount = (u_short *)(void *)_gmoninuse;
242 _gmoninuse = p;
243 }
244 mutex_unlock(&_gmonlock);
245 thr_setspecific(_gmonkey, p);
246
247 return p;
248 }
249
250 static void
251 _m_gmon_merge_two(struct gmonparam *p, struct gmonparam *q)
252 {
253 u_long fromindex;
254 u_short *frompcindex, qtoindex, toindex;
255 u_long selfpc;
256 u_long endfrom;
257 long count;
258 struct tostruct *top;
259
260 endfrom = (q->fromssize / sizeof(*q->froms));
261 for (fromindex = 0; fromindex < endfrom; fromindex++) {
262 if (q->froms[fromindex] == 0)
263 continue;
264 for (qtoindex = q->froms[fromindex]; qtoindex != 0;
265 qtoindex = q->tos[qtoindex].link) {
266 selfpc = q->tos[qtoindex].selfpc;
267 count = q->tos[qtoindex].count;
268 /* cribbed from mcount */
269 frompcindex = &p->froms[fromindex];
270 toindex = *frompcindex;
271 if (toindex == 0) {
272 /*
273 * first time traversing this arc
274 */
275 toindex = ++p->tos[0].link;
276 if (toindex >= p->tolimit)
277 /* halt further profiling */
278 goto overflow;
279
280 *frompcindex = (u_short)toindex;
281 top = &p->tos[(size_t)toindex];
282 top->selfpc = selfpc;
283 top->count = count;
284 top->link = 0;
285 goto done;
286 }
287 top = &p->tos[(size_t)toindex];
288 if (top->selfpc == selfpc) {
289 /*
290 * arc at front of chain; usual case.
291 */
292 top->count+= count;
293 goto done;
294 }
295 /*
296 * have to go looking down chain for it.
297 * top points to what we are looking at,
298 * we know it is not at the head of the chain.
299 */
300 for (; /* goto done */; ) {
301 if (top->link == 0) {
302 /*
303 * top is end of the chain and
304 * none of the chain had
305 * top->selfpc == selfpc. so
306 * we allocate a new tostruct
307 * and link it to the head of
308 * the chain.
309 */
310 toindex = ++p->tos[0].link;
311 if (toindex >= p->tolimit)
312 goto overflow;
313
314 top = &p->tos[(size_t)toindex];
315 top->selfpc = selfpc;
316 top->count = count;
317 top->link = *frompcindex;
318 *frompcindex = (u_short)toindex;
319 goto done;
320 }
321 /*
322 * otherwise, check the next arc on the chain.
323 */
324 top = &p->tos[top->link];
325 if (top->selfpc == selfpc) {
326 /*
327 * there it is.
328 * add to its count.
329 */
330 top->count += count;
331 goto done;
332 }
333
334 }
335
336 done: ;
337 }
338
339 }
340 overflow: ;
341
342 }
343
344 static void
345 _m_gmon_merge(void)
346 {
347 struct gmonparam *q;
348
349 mutex_lock(&_gmonlock);
350
351 for (q = _gmonfree; q != NULL;
352 q = (struct gmonparam *)(void *)q->kcount)
353 _m_gmon_merge_two(&_gmonparam, q);
354
355 for (q = _gmoninuse; q != NULL;
356 q = (struct gmonparam *)(void *)q->kcount) {
357 q->state = GMON_PROF_OFF;
358 _m_gmon_merge_two(&_gmonparam, q);
359 }
360
361 mutex_unlock(&_gmonlock);
362 }
363 #endif
364
365 void
366 _mcleanup(void)
367 {
368 int fd;
369 int fromindex;
370 int endfrom;
371 u_long frompc;
372 int toindex;
373 struct rawarc rawarc;
374 struct gmonparam *p = &_gmonparam;
375 struct gmonhdr gmonhdr, *hdr;
376 struct clockinfo clockinfo;
377 int mib[2];
378 size_t size;
379 char *profdir;
380 const char *proffile;
381 char buf[PATH_MAX];
382 #ifdef DEBUG
383 int logfd, len;
384 char buf2[200];
385 #endif
386
387 /*
388 * We disallow writing to the profiling file, if we are a
389 * set{u,g}id program and our effective {u,g}id does not match
390 * our real one.
391 */
392 if (issetugid() && (geteuid() != getuid() || getegid() != getgid())) {
393 warnx("%s: Profiling of set{u,g}id binaries is not"
394 " allowed", __func__);
395 return;
396 }
397
398 if (p->state == GMON_PROF_ERROR)
399 warnx("%s: tos overflow", __func__);
400
401 size = sizeof(clockinfo);
402 mib[0] = CTL_KERN;
403 mib[1] = KERN_CLOCKRATE;
404 if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
405 /*
406 * Best guess
407 */
408 clockinfo.profhz = hertz();
409 } else if (clockinfo.profhz == 0) {
410 if (clockinfo.hz != 0)
411 clockinfo.profhz = clockinfo.hz;
412 else
413 clockinfo.profhz = hertz();
414 }
415
416 moncontrol(0);
417
418 if ((profdir = getenv("PROFDIR")) != NULL) {
419 /* If PROFDIR contains a null value, no profiling
420 output is produced */
421 if (*profdir == '\0')
422 return;
423
424 if (snprintf(buf, sizeof buf, "%s/%d.%s",
425 profdir, getpid(), getprogname()) >= (int)(sizeof buf)) {
426 warnx("%s: internal buffer overflow, PROFDIR too long",
427 __func__);
428 return;
429 }
430
431 proffile = buf;
432 } else {
433 proffile = "gmon.out";
434 }
435
436 #define OPEN_FLAGS (O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC)
437 fd = open(proffile, OPEN_FLAGS, 0666);
438 if (fd < 0) {
439 warn("%s: Cannot open `%s'", __func__, proffile);
440 return;
441 }
442 #ifdef DEBUG
443 logfd = open("gmon.log", OPEN_FLAGS, 0664);
444 if (logfd < 0) {
445 warn("%s: Cannot open `%s'", __func__, "gmon.log");
446 (void)close(fd);
447 return;
448 }
449 len = snprintf(buf2, sizeof buf2, "[mcleanup1] kcount %p ssiz %lu\n",
450 p->kcount, p->kcountsize);
451 (void)write(logfd, buf2, (size_t)len);
452 #endif
453 #ifdef _REENTRANT
454 _m_gmon_merge();
455 #endif
456 hdr = (struct gmonhdr *)&gmonhdr;
457 hdr->lpc = p->lowpc;
458 hdr->hpc = p->highpc;
459 hdr->ncnt = (int)(p->kcountsize + sizeof(gmonhdr));
460 hdr->version = GMONVERSION;
461 hdr->profrate = clockinfo.profhz;
462 (void)write(fd, hdr, sizeof *hdr);
463 (void)write(fd, p->kcount, (size_t)p->kcountsize);
464 endfrom = (int)(p->fromssize / sizeof(*p->froms));
465 for (fromindex = 0; fromindex < endfrom; fromindex++) {
466 if (p->froms[fromindex] == 0)
467 continue;
468
469 frompc = p->lowpc;
470 frompc += fromindex * p->hashfraction * sizeof(*p->froms);
471 for (toindex = p->froms[fromindex]; toindex != 0;
472 toindex = p->tos[toindex].link) {
473 #ifdef DEBUG
474 len = snprintf(buf2, sizeof buf2,
475 "[mcleanup2] frompc 0x%lx selfpc 0x%lx count %lu\n" ,
476 (u_long)frompc, (u_long)p->tos[toindex].selfpc,
477 (u_long)p->tos[toindex].count);
478 (void)write(logfd, buf2, (size_t)len);
479 #endif
480 rawarc.raw_frompc = frompc;
481 rawarc.raw_selfpc = p->tos[toindex].selfpc;
482 rawarc.raw_count = p->tos[toindex].count;
483 (void)write(fd, &rawarc, sizeof rawarc);
484 }
485 }
486 (void)close(fd);
487 #ifdef DEBUG
488 (void)close(logfd);
489 #endif
490 }
491
492 /*
493 * Control profiling
494 * profiling is what mcount checks to see if
495 * all the data structures are ready.
496 */
497 void
498 moncontrol(int mode)
499 {
500 struct gmonparam *p = &_gmonparam;
501
502 if (mode) {
503 /* start */
504 profil((char *)(void *)p->kcount, (size_t)p->kcountsize,
505 p->lowpc, s_scale);
506 p->state = GMON_PROF_ON;
507 } else {
508 /* stop */
509 profil(NULL, 0, (u_long)0, 0);
510 p->state = GMON_PROF_OFF;
511 }
512 }
513
514 /*
515 * discover the tick frequency of the machine
516 * if something goes wrong, we return 0, an impossible hertz.
517 */
518 static int
519 hertz(void)
520 {
521 struct itimerspec tim;
522 timer_t t;
523 int rv = 0;
524
525 tim.it_interval.tv_sec = 0;
526 tim.it_interval.tv_nsec = 1;
527 tim.it_value.tv_sec = 0;
528 tim.it_value.tv_nsec = 0;
529
530 if (timer_create(CLOCK_REALTIME, NULL, &t) == -1)
531 return 0;
532
533 if (timer_settime(t, 0, &tim, NULL) == -1)
534 goto out;
535
536 if (timer_gettime(t, &tim) == -1)
537 goto out;
538
539 if (tim.it_interval.tv_nsec < 2)
540 goto out;
541
542 rv = (int)(1000000000LL / tim.it_interval.tv_nsec);
543 out:
544 (void)timer_delete(t);
545 return rv;
546 }
547