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/*
* profil.c -- user space version of the profil(2) system call
* Copyright (C) 1992, 1993 Rick Sladkey <jrs@world.std.com>
* Modified for m68k by Andreas Schwab <schwab@issan.uni-dortmund.de>
*
* This file is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*/
/*
* IMPORTANT:
*
* This file should never be compiled with -p or -pg!
* It will need special consideration in the Makefile for libc_p.a
* to ensure that it is not compiled with any profiling flags.
*
* Limitations:
*
* - Any program that tries to use SIGPROF itimers and profil at the
* same time won't work.
*
* - The user's program is free to trash our handler with a call to
* signal or sigaction.
*
* - Calling profil with an invalid buffer will cause a core dump instead
* of just disabling profiling.
*
* - The precision of the histogram is worse than with true kernel
* profiling.
*
*/
#include <stdio.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
static struct sigaction old_sa;
static struct itimerval old_it;
static unsigned long prof_buf;
static int prof_bufsiz;
static int prof_offset;
static int prof_scale = 0;
struct sigcontext
{
unsigned long sc_mask;
unsigned long sc_usp;
unsigned long sc_d0;
unsigned long sc_d1;
unsigned long sc_a0;
unsigned long sc_a1;
unsigned short sc_sr;
unsigned long sc_pc;
unsigned short sc_formatvec;
};
static void
_profil_handler(int signr, int code, struct sigcontext *scp)
{
unsigned long pc, spot;
#ifdef PROFIL_DEBUG
printf("pc = %#x\n", scp->sc_pc);
#endif
pc = scp->sc_pc - prof_offset;
spot = (prof_scale*(pc >> 16)
+ ((prof_scale*(pc & (0x10000 - 1))) >> 16)) & ~1;
if (spot < prof_bufsiz)
++*((unsigned short *) (spot + prof_buf));
}
int
profil(char *buf, int bufsiz, int offset, int scale)
{
struct sigaction new_sa;
struct itimerval new_it;
int old_scale = prof_scale;
if (!buf || bufsiz == 0 || scale < 2) {
if (prof_scale) {
setitimer(ITIMER_PROF, &old_it, &new_it);
sigaction(SIGPROF, &old_sa, &new_sa);
}
prof_scale = 0;
}
else {
prof_buf = (unsigned long) buf;
prof_bufsiz = bufsiz;
prof_offset = offset;
prof_scale = scale;
if (!old_scale) {
prof_scale = scale;
new_sa.sa_handler =
(void (*)(int)) _profil_handler;
new_sa.sa_mask = 0;
#ifdef SA_RESTART
new_sa.sa_flags = SA_RESTART;
#else
new_sa.sa_flags = 0;
#endif
new_it.it_interval.tv_sec = 0;
new_it.it_interval.tv_usec = 1;
new_it.it_value.tv_sec = 0;
new_it.it_value.tv_usec = 1;
sigaction(SIGPROF, &new_sa, &old_sa);
setitimer(ITIMER_PROF, &new_it, &old_it);
}
}
return 0;
}
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