From: Christos Zoulas <christos@zoulas.com>
Date: Wed, 20 Jun 2012 22:33:43 +0000 (+0000)
Subject: PR/175: Add visibility support
X-Git-Tag: FILE5_12~89
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4c04b5bf2ce5883e55f31693bc779424fbfc1a85;p=file

PR/175: Add visibility support
---

diff --git a/configure.ac b/configure.ac
index 29d0893b..ee05b381 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,9 +1,9 @@
 dnl Process this file with autoconf to produce a configure script.
-AC_INIT(file, 5.11, christos@astron.com)
-AM_INIT_AUTOMAKE()
+AC_INIT([file],[5.11],[christos@astron.com])
+AM_INIT_AUTOMAKE([subdir-objects foreign])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 
 AC_MSG_CHECKING(for builtin ELF support)
@@ -66,15 +66,16 @@ AC_SUBST(fsect)
 AM_CONDITIONAL(FSECT5, test x$fsect = x5)
 
 AC_SUBST(WARNINGS)
-AC_GNU_SOURCE
 
 dnl Checks for programs.
-AC_PROG_CC
+AC_PROG_CC_STDC
+AC_USE_SYSTEM_EXTENSIONS
 AM_PROG_CC_C_O
+AC_C_BIGENDIAN
 AC_PROG_INSTALL
 AC_PROG_LN_S
-AC_PROG_LIBTOOL
-
+LT_INIT([disable-static pic-only])
+gl_VISIBILITY
 dnl Checks for headers
 AC_HEADER_STDC
 AC_HEADER_MAJOR
@@ -91,45 +92,24 @@ AC_TYPE_OFF_T
 AC_TYPE_SIZE_T
 AC_CHECK_MEMBERS([struct stat.st_rdev])
 
-AC_STRUCT_TM
-AC_CHECK_MEMBERS([struct tm.tm_gmtoff, struct tm.tm_zone])
+AC_CHECK_MEMBERS([struct tm.tm_gmtoff])
+AC_STRUCT_TIMEZONE
 AC_STRUCT_TIMEZONE_DAYLIGHT
 AC_SYS_LARGEFILE
 AC_FUNC_FSEEKO
 AC_TYPE_MBSTATE_T
 
 AC_STRUCT_OPTION_GETOPT_H
-
-AC_CHECK_TYPES([pid_t, uint8_t, uint16_t, uint32_t, int32_t, uint64_t, int64_t])
-AC_CHECK_SIZEOF(long long)
-AH_BOTTOM([
-#ifndef HAVE_UINT8_T
-typedef unsigned char uint8_t;
-#endif
-#ifndef HAVE_UINT16_T
-typedef unsigned short uint16_t;
-#endif
-#ifndef HAVE_UINT32_T
-typedef unsigned int uint32_t;
-#endif
-#ifndef HAVE_INT32_T
-typedef int int32_t;
-#endif
-#ifndef HAVE_UINT64_T
-#if SIZEOF_LONG_LONG == 8
-typedef unsigned long long uint64_t;
-#else
-typedef unsigned long uint64_t;
-#endif
-#endif
-#ifndef HAVE_INT64_T
-#if SIZEOF_LONG_LONG == 8
-typedef long long int64_t;
-#else
-typedef long int64_t;
-#endif
-#endif
-])
+AC_TYPE_PID_T
+AC_TYPE_UINT8_T
+AC_TYPE_UINT16_T
+AC_TYPE_UINT32_T
+AC_TYPE_INT32_T
+AC_TYPE_UINT64_T
+AC_TYPE_INT64_T
+AC_FUNC_MMAP
+AC_FUNC_FORK
+AC_FUNC_MBRTOWC
 
 AC_MSG_CHECKING(for gcc compiler warnings)
 AC_ARG_ENABLE(warnings,
@@ -156,7 +136,7 @@ else
 fi])
 
 dnl Checks for functions
-AC_CHECK_FUNCS(mmap strerror strndup strtoul mbrtowc mkstemp utimes utime wcwidth strtof fork)
+AC_CHECK_FUNCS(strerror strndup strtoul mkstemp mkostemp utimes utime wcwidth strtof)
 
 dnl Provide implementation of some required functions if necessary
 AC_REPLACE_FUNCS(getopt_long asprintf vasprintf strlcpy strlcat getline ctime_r asctime_r)
diff --git a/src/Makefile.am b/src/Makefile.am
index 968e5849..8657cb34 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,7 +5,7 @@ include_HEADERS = magic.h
 bin_PROGRAMS = file
 
 AM_CPPFLAGS = -DMAGIC='"$(MAGIC)"'
-AM_CFLAGS = @WARNINGS@
+AM_CFLAGS = $(CFLAG_VISIBILITY) @WARNINGS@
 
 libmagic_la_SOURCES = magic.c apprentice.c softmagic.c ascmagic.c \
 	encoding.c compress.c is_tar.c readelf.c print.c fsmagic.c \
diff --git a/src/file.h b/src/file.h
index 4eb1b2f3..1ad67975 100644
--- a/src/file.h
+++ b/src/file.h
@@ -27,7 +27,7 @@
  */
 /*
  * file.h - definitions for file(1) program
- * @(#)$File: file.h,v 1.136 2012/04/03 22:25:07 christos Exp $
+ * @(#)$File: file.h,v 1.137 2012/05/15 17:14:36 christos Exp $
  */
 
 #ifndef __file_h__
@@ -82,10 +82,18 @@
 #endif
 
 #define private static
+
+#if HAVE_VISIBILITY
+#define public  __attribute__ ((__visibility__("default")))
 #ifndef protected
-#define protected
+#define protected __attribute__ ((__visibility__("hidden")))
 #endif
+#else
 #define public
+#ifndef protected
+#define protected
+#endif
+#endif
 
 #ifndef __arraycount
 #define __arraycount(a) (sizeof(a) / sizeof(a[0]))
diff --git a/src/readelf.c b/src/readelf.c
index 08d36c67..deb6d311 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -27,7 +27,7 @@
 #include "file.h"
 
 #ifndef lint
-FILE_RCSID("@(#)$File: readelf.c,v 1.90 2011/08/23 08:01:12 christos Exp $")
+FILE_RCSID("@(#)$File: readelf.c,v 1.91 2012/05/22 01:55:12 christos Exp $")
 #endif
 
 #ifdef BUILTIN_ELF
@@ -58,7 +58,9 @@ private size_t donote(struct magic_set *, void *, size_t, size_t, int,
 
 private uint16_t getu16(int, uint16_t);
 private uint32_t getu32(int, uint32_t);
+#ifndef USE_ARRAY_FOR_64BIT_TYPES
 private uint64_t getu64(int, uint64_t);
+#endif
 
 private uint16_t
 getu16(int swap, uint16_t value)
@@ -100,6 +102,7 @@ getu32(int swap, uint32_t value)
 		return value;
 }
 
+#ifndef USE_ARRAY_FOR_64BIT_TYPES
 private uint64_t
 getu64(int swap, uint64_t value)
 {
@@ -124,6 +127,7 @@ getu64(int swap, uint64_t value)
 	} else
 		return value;
 }
+#endif
 
 #define elf_getu16(swap, value) getu16(swap, value)
 #define elf_getu32(swap, value) getu32(swap, value)
diff --git a/visibility.m4 b/visibility.m4
new file mode 100644
index 00000000..7b24d39e
--- /dev/null
+++ b/visibility.m4
@@ -0,0 +1,77 @@
+# visibility.m4 serial 4 (gettext-0.18.2)
+dnl Copyright (C) 2005, 2008, 2010-2012 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Tests whether the compiler supports the command-line option
+dnl -fvisibility=hidden and the function and variable attributes
+dnl __attribute__((__visibility__("hidden"))) and
+dnl __attribute__((__visibility__("default"))).
+dnl Does *not* test for __visibility__("protected") - which has tricky
+dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
+dnl MacOS X.
+dnl Does *not* test for __visibility__("internal") - which has processor
+dnl dependent semantics.
+dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
+dnl "really only recommended for legacy code".
+dnl Set the variable CFLAG_VISIBILITY.
+dnl Defines and sets the variable HAVE_VISIBILITY.
+
+AC_DEFUN([gl_VISIBILITY],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  CFLAG_VISIBILITY=
+  HAVE_VISIBILITY=0
+  if test -n "$GCC"; then
+    dnl First, check whether -Werror can be added to the command line, or
+    dnl whether it leads to an error because of some other option that the
+    dnl user has put into $CC $CFLAGS $CPPFLAGS.
+    AC_MSG_CHECKING([whether the -Werror option is usable])
+    AC_CACHE_VAL([gl_cv_cc_vis_werror], [
+      gl_save_CFLAGS="$CFLAGS"
+      CFLAGS="$CFLAGS -Werror"
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[]], [[]])],
+        [gl_cv_cc_vis_werror=yes],
+        [gl_cv_cc_vis_werror=no])
+      CFLAGS="$gl_save_CFLAGS"])
+    AC_MSG_RESULT([$gl_cv_cc_vis_werror])
+    dnl Now check whether visibility declarations are supported.
+    AC_MSG_CHECKING([for simple visibility declarations])
+    AC_CACHE_VAL([gl_cv_cc_visibility], [
+      gl_save_CFLAGS="$CFLAGS"
+      CFLAGS="$CFLAGS -fvisibility=hidden"
+      dnl We use the option -Werror and a function dummyfunc, because on some
+      dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
+      dnl "visibility attribute not supported in this configuration; ignored"
+      dnl at the first function definition in every compilation unit, and we
+      dnl don't want to use the option in this case.
+      if test $gl_cv_cc_vis_werror = yes; then
+        CFLAGS="$CFLAGS -Werror"
+      fi
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
+             extern __attribute__((__visibility__("default"))) int exportedvar;
+             extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
+             extern __attribute__((__visibility__("default"))) int exportedfunc (void);
+             void dummyfunc (void) {}
+           ]],
+           [[]])],
+        [gl_cv_cc_visibility=yes],
+        [gl_cv_cc_visibility=no])
+      CFLAGS="$gl_save_CFLAGS"])
+    AC_MSG_RESULT([$gl_cv_cc_visibility])
+    if test $gl_cv_cc_visibility = yes; then
+      CFLAG_VISIBILITY="-fvisibility=hidden"
+      HAVE_VISIBILITY=1
+    fi
+  fi
+  AC_SUBST([CFLAG_VISIBILITY])
+  AC_SUBST([HAVE_VISIBILITY])
+  AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
+    [Define to 1 or 0, depending whether the compiler supports simple visibility declarations.])
+])