Description:
A simplified variant of GNU libsigsegv.
It implements the most important features of GNU libsigsegv: catching SIGSEGV
and catching stack overflow. It does *not* implement the 'sigsegv_dispatcher'
type (which is not multithread-safe).
It supports all modern Unix-like platforms: Linux, Hurd, FreeBSD, NetBSD,
OpenBSD, macOS, AIX, Solaris, Cygwin, Haiku, even IRIX. It does *not* support
HP-UX, Minix, native Windows; on these platforms the module compiles and
provides a <sigsegv.h> header file, but it does not define HAVE_SIGSEGV_RECOVERY
and HAVE_STACK_OVERFLOW_RECOVERY.
Unlike GNU libsigsegv, which consists of many .h and .c files, this module
compiles to just two object files, rather than a library.

Files:
lib/sigsegv.in.h
lib/sigsegv.c
lib/stackvma.h
lib/stackvma.c
m4/mmap-anon.m4
m4/musl.m4
m4/sigaltstack.m4
m4/stack-direction.m4
m4/libsigsegv.m4
m4/sigsegv.m4

Depends-on:
gen-header
havelib
host-cpu-c-abi
stdint
getpagesize

configure.ac:
AC_REQUIRE([gl_SIGSEGV])
if test $gl_sigsegv_uses_libsigsegv = yes; then
  GL_GENERATE_SIGSEGV_H=false
else
  GL_GENERATE_SIGSEGV_H=true
fi
gl_CONDITIONAL_HEADER([sigsegv.h])
AC_PROG_MKDIR_P
if $GL_GENERATE_SIGSEGV_H; then
  dnl Persuade glibc <sys/ucontext.h> to declare macros designating register
  dnl indices: REG_RSP on x86_64, REG_ESP on i386.
  dnl Persuade Solaris OpenIndiana <ucontext.h> to include <sys/regset.h>,
  dnl which declares macros designating register indices, such as ESP on i386.
  dnl Persuade Solaris OpenIndiana <unistd.h> to declare mincore().
  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

  gl_MUSL_LIBC

  AC_REQUIRE([AC_CANONICAL_HOST])
  case "$host_os" in
    solaris2.11)
      AC_DEFINE([SOLARIS11], [1], [Define on Solaris 11 and its derivates.])
      ;;
  esac

  gl_FUNC_MMAP_ANON

  dnl Stack direction.
  SV_STACK_DIRECTION

  dnl Catching stack overflow requires an alternate signal stack.
  dnl The old "install a guard page" trick would be unreliable, because
  dnl we don't know where exactly to place the guard page.
  SV_SIGALTSTACK

  AC_CHECK_FUNCS_ONCE([getrlimit])
fi

Makefile.am:
BUILT_SOURCES += $(SIGSEGV_H)

if GL_GENERATE_SIGSEGV_H
sigsegv.h: sigsegv.in.h $(top_builddir)/config.status
@NMD@	$(AM_V_GEN)$(MKDIR_P) '%reldir%'
	$(gl_V_at)$(SED_HEADER_TO_AT_t) $(srcdir)/sigsegv.in.h
	$(AM_V_at)mv $@-t $@
else
sigsegv.h: $(top_builddir)/config.status
	rm -f $@
endif
MOSTLYCLEANFILES += sigsegv.h sigsegv.h-t

if GL_GENERATE_SIGSEGV_H
lib_SOURCES += sigsegv.c stackvma.c
endif

Include:
<sigsegv.h>

Link:
$(LTLIBSIGSEGV) when linking with libtool, $(LIBSIGSEGV) otherwise

License:
GPLv2+

Maintainer:
Bruno Haible