aboutsummaryrefslogtreecommitdiff
path: root/gmon/gmon.c
blob: 996b6a62a4a656ade0966d591dc8698184a1af39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
/*-
 * Copyright (c) 1983, 1992, 1993, 2011
 *	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.
 * 4. 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/param.h>
#include <sys/time.h>
#include <sys/gmon.h>
#include <sys/gmon_out.h>
#include <sys/uio.h>

#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <wchar.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <unistd.h>
#include <libc-internal.h>
#include <not-cancel.h>

#define TUNABLE_NAMESPACE gmon
#include <elf/dl-tunables.h>

#ifdef PIC
# include <link.h>

static int
callback (struct dl_phdr_info *info, size_t size, void *data)
{
  if (info->dlpi_name[0] == '\0')
    {
      /* The link map for the executable is created by calling
	 _dl_new_object with "" as filename.  dl_iterate_phdr
	 calls the callback function with filename from the
	 link map as dlpi_name.  */
      u_long *load_address = data;
      *load_address = (u_long) info->dlpi_addr;
      return 1;
    }

  return 0;
}
#endif

/*  Head of basic-block list or NULL. */
struct __bb *__bb_head attribute_hidden;

struct gmonparam _gmonparam attribute_hidden = { GMON_PROF_OFF };

/*
 * See profil(2) where this is described:
 */
static int	s_scale;
#define		SCALE_1_TO_1	0x10000L

#define ERR(s) __write_nocancel (STDERR_FILENO, s, sizeof (s) - 1)

void moncontrol (int mode);
void __moncontrol (int mode);
libc_hidden_proto (__moncontrol)
static void write_hist (int fd, u_long load_address);
static void write_call_graph (int fd, u_long load_address);
static void write_bb_counts (int fd);

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

  /* Treat start request as stop if error or gmon not initialized. */
  if (mode && p->state != GMON_PROF_ERROR && p->tos != NULL)
    {
      /* start */
      __profil((void *) p->kcount, p->kcountsize, p->lowpc, s_scale);
      p->state = GMON_PROF_ON;
    }
  else
    {
      /* stop */
      __profil(NULL, 0, 0, 0);
      /* Don't change the state if we ran into an error. */
      if (p->state != GMON_PROF_ERROR)
        p->state = GMON_PROF_OFF;
    }
}
libc_hidden_def (__moncontrol)
weak_alias (__moncontrol, moncontrol)


void
__monstartup (u_long lowpc, u_long highpc)
{
  int o;
  char *cp;
  struct gmonparam *p = &_gmonparam;
  long int minarcs, maxarcs;

  /* Read minarcs/maxarcs tunables. */
  minarcs = TUNABLE_GET (minarcs, int32_t, NULL);
  maxarcs = TUNABLE_GET (maxarcs, int32_t, NULL);
  if (maxarcs < minarcs)
    {
      ERR("monstartup: maxarcs < minarcs, setting maxarcs = minarcs\n");
      maxarcs = minarcs;
    }

  /*
   * If we are incorrectly called twice in a row (without an
   * intervening call to _mcleanup), ignore the second call to
   * prevent leaking memory.
   */
  if (p->tos != NULL)
      return;

  /*
   * 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;
  /* This looks like a typo, but it's here to align the p->froms
     section.  */
  p->kcountsize = ROUNDUP(p->textsize / HISTFRACTION, sizeof(*p->froms));
  p->hashfraction = HASHFRACTION;
  p->log_hashfraction = -1;
  /* The following test must be kept in sync with the corresponding
     test in mcount.c.  */
  if ((HASHFRACTION & (HASHFRACTION - 1)) == 0) {
      /* if HASHFRACTION is a power of two, mcount can use shifting
	 instead of integer division.  Precompute shift amount. */
      p->log_hashfraction = ffs(p->hashfraction * sizeof(*p->froms)) - 1;
  }
  p->fromssize = ROUNDUP(p->textsize / HASHFRACTION, sizeof(*p->froms));
  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 = calloc (p->kcountsize + p->fromssize + p->tossize, 1);
  if (! cp)
    {
      ERR("monstartup: out of memory\n");
      p->tos = NULL;
      p->state = GMON_PROF_ERROR;
      return;
    }
  p->tos = (struct tostruct *)cp;
  cp += p->tossize;
  p->kcount = (HISTCOUNTER *)cp;
  cp += p->kcountsize;
  p->froms = (ARCINDEX *)cp;

  p->tos[0].link = 0;

  o = p->highpc - p->lowpc;
  if (p->kcountsize < (u_long) o)
    {
#ifndef hp300
      s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
#else
      /* avoid floating point operations */
      int 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);
}
weak_alias (__monstartup, monstartup)


static void
write_hist (int fd, u_long load_address)
{
  u_char tag = GMON_TAG_TIME_HIST;

  if (_gmonparam.kcountsize > 0)
    {
      struct real_gmon_hist_hdr
      {
	char *low_pc;
	char *high_pc;
	int32_t hist_size;
	int32_t prof_rate;
	char dimen[15];
	char dimen_abbrev;
      } thdr;
      struct iovec iov[3] =
	{
	  { &tag, sizeof (tag) },
	  { &thdr, sizeof (struct gmon_hist_hdr) },
	  { _gmonparam.kcount, _gmonparam.kcountsize }
	};

      if (sizeof (thdr) != sizeof (struct gmon_hist_hdr)
	  || (offsetof (struct real_gmon_hist_hdr, low_pc)
	      != offsetof (struct gmon_hist_hdr, low_pc))
	  || (offsetof (struct real_gmon_hist_hdr, high_pc)
	      != offsetof (struct gmon_hist_hdr, high_pc))
	  || (offsetof (struct real_gmon_hist_hdr, hist_size)
	      != offsetof (struct gmon_hist_hdr, hist_size))
	  || (offsetof (struct real_gmon_hist_hdr, prof_rate)
	      != offsetof (struct gmon_hist_hdr, prof_rate))
	  || (offsetof (struct real_gmon_hist_hdr, dimen)
	      != offsetof (struct gmon_hist_hdr, dimen))
	  || (offsetof (struct real_gmon_hist_hdr, dimen_abbrev)
	      != offsetof (struct gmon_hist_hdr, dimen_abbrev)))
	abort ();

      thdr.low_pc = (char *) _gmonparam.lowpc - load_address;
      thdr.high_pc = (char *) _gmonparam.highpc - load_address;
      thdr.hist_size = _gmonparam.kcountsize / sizeof (HISTCOUNTER);
      thdr.prof_rate = __profile_frequency ();
      strncpy (thdr.dimen, "seconds", sizeof (thdr.dimen));
      thdr.dimen_abbrev = 's';

      __writev_nocancel_nostatus (fd, iov, 3);
    }
}


static void
write_call_graph (int fd, u_long load_address)
{
#define NARCS_PER_WRITEV	32
  u_char tag = GMON_TAG_CG_ARC;
  struct gmon_cg_arc_record raw_arc[NARCS_PER_WRITEV]
    __attribute__ ((aligned (__alignof__ (char*))));
  ARCINDEX from_index, to_index;
  u_long from_len;
  u_long frompc;
  struct iovec iov[2 * NARCS_PER_WRITEV];
  int nfilled;

  for (nfilled = 0; nfilled < NARCS_PER_WRITEV; ++nfilled)
    {
      iov[2 * nfilled].iov_base = &tag;
      iov[2 * nfilled].iov_len = sizeof (tag);

      iov[2 * nfilled + 1].iov_base = &raw_arc[nfilled];
      iov[2 * nfilled + 1].iov_len = sizeof (struct gmon_cg_arc_record);
    }

  nfilled = 0;
  from_len = _gmonparam.fromssize / sizeof (*_gmonparam.froms);
  for (from_index = 0; from_index < from_len; ++from_index)
    {
      if (_gmonparam.froms[from_index] == 0)
	continue;

      frompc = _gmonparam.lowpc;
      frompc += (from_index * _gmonparam.hashfraction
		 * sizeof (*_gmonparam.froms));
      for (to_index = _gmonparam.froms[from_index];
	   to_index != 0;
	   to_index = _gmonparam.tos[to_index].link)
	{
	  struct arc
	    {
	      char *frompc;
	      char *selfpc;
	      int32_t count;
	    }
	  arc;

	  arc.frompc = (char *) frompc - load_address;
	  arc.selfpc = ((char *) _gmonparam.tos[to_index].selfpc
			- load_address);
	  arc.count  = _gmonparam.tos[to_index].count;
	  memcpy (raw_arc + nfilled, &arc, sizeof (raw_arc [0]));

	  if (++nfilled == NARCS_PER_WRITEV)
	    {
	      __writev_nocancel_nostatus (fd, iov, 2 * nfilled);
	      nfilled = 0;
	    }
	}
    }
  if (nfilled > 0)
    __writev_nocancel_nostatus (fd, iov, 2 * nfilled);
}


static void
write_bb_counts (int fd)
{
  struct __bb *grp;
  u_char tag = GMON_TAG_BB_COUNT;
  size_t ncounts;
  size_t i;

  struct iovec bbhead[2] =
    {
      { &tag, sizeof (tag) },
      { &ncounts, sizeof (ncounts) }
    };
  struct iovec bbbody[8];
  size_t nfilled;

  for (i = 0; i < (sizeof (bbbody) / sizeof (bbbody[0])); i += 2)
    {
      bbbody[i].iov_len = sizeof (grp->addresses[0]);
      bbbody[i + 1].iov_len = sizeof (grp->counts[0]);
    }

  /* Write each group of basic-block info (all basic-blocks in a
     compilation unit form a single group). */

  for (grp = __bb_head; grp; grp = grp->next)
    {
      ncounts = grp->ncounts;
      __writev_nocancel_nostatus (fd, bbhead, 2);
      for (nfilled = i = 0; i < ncounts; ++i)
	{
	  if (nfilled > (sizeof (bbbody) / sizeof (bbbody[0])) - 2)
	    {
	      __writev_nocancel_nostatus (fd, bbbody, nfilled);
	      nfilled = 0;
	    }

	  bbbody[nfilled++].iov_base = (char *) &grp->addresses[i];
	  bbbody[nfilled++].iov_base = &grp->counts[i];
	}
      if (nfilled > 0)
	__writev_nocancel_nostatus (fd, bbbody, nfilled);
    }
}


static void
write_gmon (void)
{
    int fd = -1;
    char *env;

    env = getenv ("GMON_OUT_PREFIX");
    if (env != NULL && !__libc_enable_secure)
      {
	size_t len = strlen (env);
	char buf[len + 20];
	__snprintf (buf, sizeof (buf), "%s.%u", env, __getpid ());
	fd = __open_nocancel (buf, O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW
			      | O_CLOEXEC, 0666);
      }

    if (fd == -1)
      {
	fd = __open_nocancel ("gmon.out", O_CREAT | O_TRUNC | O_WRONLY
			      | O_NOFOLLOW | O_CLOEXEC, 0666);
	if (fd < 0)
	  {
	    char buf[300];
	    int errnum = errno;
	    __fxprintf (NULL, "_mcleanup: gmon.out: %s\n",
			__strerror_r (errnum, buf, sizeof buf));
	    return;
	  }
      }

    /* write gmon.out header: */
    struct real_gmon_hdr
    {
      char cookie[4];
      int32_t version;
      char spare[3 * 4];
    } ghdr;
    if (sizeof (ghdr) != sizeof (struct gmon_hdr)
	|| (offsetof (struct real_gmon_hdr, cookie)
	    != offsetof (struct gmon_hdr, cookie))
	|| (offsetof (struct real_gmon_hdr, version)
	    != offsetof (struct gmon_hdr, version)))
      abort ();
    memcpy (&ghdr.cookie[0], GMON_MAGIC, sizeof (ghdr.cookie));
    ghdr.version = GMON_VERSION;
    memset (ghdr.spare, '\0', sizeof (ghdr.spare));
    __write_nocancel (fd, &ghdr, sizeof (struct gmon_hdr));

    /* Get load_address to profile PIE.  */
    u_long load_address = 0;
#ifdef PIC
    __dl_iterate_phdr (callback, &load_address);
#endif

    /* write PC histogram: */
    write_hist (fd, load_address);

    /* write call-graph: */
    write_call_graph (fd, load_address);

    /* write basic-block execution counts: */
    write_bb_counts (fd);

    __close_nocancel_nostatus (fd);
}


#ifdef PROF
void
__write_profiling (void)
{
  int save = _gmonparam.state;
  _gmonparam.state = GMON_PROF_OFF;
  if (save == GMON_PROF_ON)
    write_gmon ();
  _gmonparam.state = save;
}

/* This symbol isn't used anywhere in the DSO and it is not exported.
   This would normally mean it should be removed to get the same API
   in static libraries.  But since profiling is special in static libs
   anyway we keep it.  But not when building the DSO since some
   quality assurance tests will otherwise trigger.  */
weak_alias (__write_profiling, write_profiling)
#endif


void
_mcleanup (void)
{
  __moncontrol (0);

  if (_gmonparam.state != GMON_PROF_ERROR && _gmonparam.tos != NULL)
    write_gmon ();

  /* free the memory. */
  free (_gmonparam.tos);

  /* reset buffer to initial state for safety */
  memset(&_gmonparam, 0, sizeof _gmonparam);
  /* somewhat confusingly, ON=0, OFF=3 */
  _gmonparam.state = GMON_PROF_OFF;
}