/* Low-level statistical profiling support function.  Mostly POSIX.1 version.

   Copyright (C) 1996-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <sys/types.h>

#include <unistd.h>

#include <errno.h>

#include <signal.h>

#include <sys/time.h>

#include <libc-internal.h>

#include <sigsetops.h>

#ifndef SIGPROF

#include <gmon/profil.c>

#else

static u_short *samples;

static size_t nsamples;

static size_t pc_offset;

static u_int pc_scale;

static inline void

profil_count (void *pc)

{

  size_t i = (pc - pc_offset - (void *) 0) / 2;

  if (sizeof (unsigned long long int) > sizeof (size_t))

    i = (unsigned long long int) i * pc_scale / 65536;

  else

    i = i / 65536 * pc_scale + i % 65536 * pc_scale / 65536;

  if (i < nsamples)

    ++samples[i];

}

/* Get the machine-dependent definition of `__profil_counter', the signal

   handler for SIGPROF.  It calls `profil_count' (above) with the PC of the

   interrupted code.  */

#include "profil-counter.h"

/* Enable statistical profiling, writing samples of the PC into at most

   SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling

   is enabled, the system examines the user PC and increments

   SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,

   disable profiling.  Returns zero on success, -1 on error.  */

int

__profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)

{

  struct sigaction act;

  struct itimerval timer;

#if !IS_IN (rtld)

  static struct sigaction oact;

  static struct itimerval otimer;

# define oact_ptr &oact

# define otimer_ptr &otimer

  if (sample_buffer == NULL)

    {

      /* Disable profiling.  */

      if (samples == NULL)

	/* Wasn't turned on.  */

	return 0;

      if (__setitimer (ITIMER_PROF, &otimer, NULL) < 0)

	return -1;

      samples = NULL;

      return __sigaction (SIGPROF, &oact, NULL);

    }

 if (samples)

    {

      /* Was already turned on.  Restore old timer and signal handler

	 first.  */

      if (__setitimer (ITIMER_PROF, &otimer, NULL) < 0

	  || __sigaction (SIGPROF, &oact, NULL) < 0)

	return -1;

    }

#else

 /* In ld.so profiling should never be disabled once it runs.  */

 //assert (sample_buffer != NULL);

# define oact_ptr NULL

# define otimer_ptr NULL

#endif

  samples = sample_buffer;

  nsamples = size / sizeof *samples;

  pc_offset = offset;

  pc_scale = scale;

  act.sa_handler = (sighandler_t) &__profil_counter;

  act.sa_flags = SA_RESTART;

  __sigfillset (&act.sa_mask);

  if (__sigaction (SIGPROF, &act, oact_ptr) < 0)

    return -1;

  timer.it_value.tv_sec = 0;

  timer.it_value.tv_usec = 1000000 / __profile_frequency ();

  timer.it_interval = timer.it_value;

  return __setitimer (ITIMER_PROF, &timer, otimer_ptr);

}

weak_alias (__profil, profil)

#endif