tor/m4/pc_from_ucontext.m4
cypherpunks 94762e37b9 Use the Autoconf macro AC_USE_SYSTEM_EXTENSIONS
The Autoconf macro AC_USE_SYSTEM_EXTENSIONS defines preprocessor macros
which turn on extensions to C and POSIX. The macro also makes it easier
for developers to use the extensions without needing (or forgetting) to
define them manually.

The macro can be safely used because it was introduced in Autoconf 2.60
and Tor requires Autoconf 2.63 and above.
2016-06-17 10:17:44 -04:00

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# This file is from Google Performance Tools, svn revision r226.
#
# The Google Performance Tools license is:
########
# Copyright (c) 2005, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * 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.
# * Neither the name of Google Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT
# OWNER 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.
########
# Original file follows below.
# We want to access the "PC" (Program Counter) register from a struct
# ucontext. Every system has its own way of doing that. We try all the
# possibilities we know about. Note REG_PC should come first (REG_RIP
# is also defined on solaris, but does the wrong thing).
# OpenBSD doesn't have ucontext.h, but we can get PC from ucontext_t
# by using signal.h.
# The first argument of AC_PC_FROM_UCONTEXT will be invoked when we
# cannot find a way to obtain PC from ucontext.
AC_DEFUN([AC_PC_FROM_UCONTEXT],
[AC_CHECK_HEADERS(ucontext.h)
# Redhat 7 has <sys/ucontext.h>, but it barfs if we #include it directly
# (this was fixed in later redhats). <ucontext.h> works fine, so use that.
if grep "Red Hat Linux release 7" /etc/redhat-release >/dev/null 2>&1; then
AC_DEFINE(HAVE_SYS_UCONTEXT_H, 0, [<sys/ucontext.h> is broken on redhat 7])
ac_cv_header_sys_ucontext_h=no
else
AC_CHECK_HEADERS(sys/ucontext.h) # ucontext on OS X 10.6 (at least)
fi
AC_CHECK_HEADERS(cygwin/signal.h) # ucontext on cywgin
AC_MSG_CHECKING([how to access the program counter from a struct ucontext])
pc_fields=" uc_mcontext.gregs[[REG_PC]]" # Solaris x86 (32 + 64 bit)
pc_fields="$pc_fields uc_mcontext.gregs[[REG_EIP]]" # Linux (i386)
pc_fields="$pc_fields uc_mcontext.gregs[[REG_RIP]]" # Linux (x86_64)
pc_fields="$pc_fields uc_mcontext.sc_ip" # Linux (ia64)
pc_fields="$pc_fields uc_mcontext.uc_regs->gregs[[PT_NIP]]" # Linux (ppc)
pc_fields="$pc_fields uc_mcontext.gregs[[R15]]" # Linux (arm old [untested])
pc_fields="$pc_fields uc_mcontext.arm_pc" # Linux (arm arch 5)
pc_fields="$pc_fields uc_mcontext.gp_regs[[PT_NIP]]" # Suse SLES 11 (ppc64)
pc_fields="$pc_fields uc_mcontext.mc_eip" # FreeBSD (i386)
pc_fields="$pc_fields uc_mcontext.mc_rip" # FreeBSD (x86_64 [untested])
pc_fields="$pc_fields uc_mcontext.__gregs[[_REG_EIP]]" # NetBSD (i386)
pc_fields="$pc_fields uc_mcontext.__gregs[[_REG_RIP]]" # NetBSD (x86_64)
pc_fields="$pc_fields uc_mcontext->ss.eip" # OS X (i386, <=10.4)
pc_fields="$pc_fields uc_mcontext->__ss.__eip" # OS X (i386, >=10.5)
pc_fields="$pc_fields uc_mcontext->ss.rip" # OS X (x86_64)
pc_fields="$pc_fields uc_mcontext->__ss.__rip" # OS X (>=10.5 [untested])
pc_fields="$pc_fields uc_mcontext->ss.srr0" # OS X (ppc, ppc64 [untested])
pc_fields="$pc_fields uc_mcontext->__ss.__srr0" # OS X (>=10.5 [untested])
pc_field_found=false
for pc_field in $pc_fields; do
if ! $pc_field_found; then
# Prefer sys/ucontext.h to ucontext.h, for OS X's sake.
if test "x$ac_cv_header_cygwin_signal_h" = xyes; then
AC_TRY_COMPILE([#include <cygwin/signal.h>],
[ucontext_t u; return u.$pc_field == 0;],
AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
How to access the PC from a struct ucontext)
AC_MSG_RESULT([$pc_field])
pc_field_found=true)
elif test "x$ac_cv_header_sys_ucontext_h" = xyes; then
AC_TRY_COMPILE([#include <sys/ucontext.h>],
[ucontext_t u; return u.$pc_field == 0;],
AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
How to access the PC from a struct ucontext)
AC_MSG_RESULT([$pc_field])
pc_field_found=true)
elif test "x$ac_cv_header_ucontext_h" = xyes; then
AC_TRY_COMPILE([#include <ucontext.h>],
[ucontext_t u; return u.$pc_field == 0;],
AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
How to access the PC from a struct ucontext)
AC_MSG_RESULT([$pc_field])
pc_field_found=true)
else # hope some standard header gives it to us
AC_TRY_COMPILE([],
[ucontext_t u; return u.$pc_field == 0;],
AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
How to access the PC from a struct ucontext)
AC_MSG_RESULT([$pc_field])
pc_field_found=true)
fi
fi
done
if ! $pc_field_found; then
pc_fields=" sc_eip" # OpenBSD (i386)
pc_fields="$pc_fields sc_rip" # OpenBSD (x86_64)
for pc_field in $pc_fields; do
if ! $pc_field_found; then
AC_TRY_COMPILE([#include <signal.h>],
[ucontext_t u; return u.$pc_field == 0;],
AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
How to access the PC from a struct ucontext)
AC_MSG_RESULT([$pc_field])
pc_field_found=true)
fi
done
fi
if ! $pc_field_found; then
[$1]
fi])