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Fix implicit fallthrough warning #54

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Fix implicit fallthrough warning #54

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3 changes: 3 additions & 0 deletions configure.ac
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@

AC_PREREQ(2.61)
AC_INIT([fcgiwrap], [1.1.0], [[email protected]])
AC_CONFIG_MACRO_DIRS([m4])
AM_CFLAGS="-std=gnu99 -Wall -Wextra -Werror -pedantic"
if test x"$CFLAGS" = x""; then
AM_CFLAGS="$AM_CFLAGS -O2 -g3"
Expand Down Expand Up @@ -62,5 +63,7 @@ AC_FUNC_MALLOC
AC_CHECK_FUNCS([strchr strdup strrchr])
AC_CHECK_FUNCS([dup2 putenv select setenv strerror],, [AC_MSG_ERROR([seems as if your libraries don't provide an expected function])])

AX_GCC_FUNC_ATTRIBUTE([fallthrough])

AC_CONFIG_FILES([Makefile])
AC_OUTPUT
7 changes: 7 additions & 0 deletions fcgiwrap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,12 @@
#define UNIX_PATH_MAX 108
#endif

#ifdef HAVE_FUNC_ATTRIBUTE_FALLTHROUGH
#define FALLTHROUGH __attribute__ ((fallthrough))
#else
#define FALLTHROUGH (void)
#endif

extern char **environ;
static char * const * inherited_environ;
static const char **allowed_programs;
Expand Down Expand Up @@ -580,6 +586,7 @@ static void handle_fcgi_request(void)
execl(filename, filename, (void *)NULL);
cgi_error("502 Bad Gateway", "Cannot execute script", filename);

FALLTHROUGH;
default: /* parent */
close(pipe_in[0]);
close(pipe_out[1]);
Expand Down
242 changes: 242 additions & 0 deletions m4/ax_gcc_func_attribute.m4
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Original file line number Diff line number Diff line change
@@ -0,0 +1,242 @@
# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE)
#
# DESCRIPTION
#
# This macro checks if the compiler supports one of GCC's function
# attributes; many other compilers also provide function attributes with
# the same syntax. Compiler warnings are used to detect supported
# attributes as unsupported ones are ignored by default so quieting
# warnings when using this macro will yield false positives.
#
# The ATTRIBUTE parameter holds the name of the attribute to be checked.
#
# If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_<ATTRIBUTE>.
#
# The macro caches its result in the ax_cv_have_func_attribute_<attribute>
# variable.
#
# The macro currently supports the following function attributes:
#
# alias
# aligned
# alloc_size
# always_inline
# artificial
# cold
# const
# constructor
# constructor_priority for constructor attribute with priority
# deprecated
# destructor
# dllexport
# dllimport
# error
# externally_visible
# fallthrough
# flatten
# format
# format_arg
# gnu_format
# gnu_inline
# hot
# ifunc
# leaf
# malloc
# noclone
# noinline
# nonnull
# noreturn
# nothrow
# optimize
# pure
# sentinel
# sentinel_position
# unused
# used
# visibility
# warning
# warn_unused_result
# weak
# weakref
#
# Unsupported function attributes will be tested with a prototype
# returning an int and not accepting any arguments and the result of the
# check might be wrong or meaningless so use with care.
#
# LICENSE
#
# Copyright (c) 2013 Gabriele Svelto <[email protected]>
#
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty provided the copyright notice
# and this notice are preserved. This file is offered as-is, without any
# warranty.

#serial 12

AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1])

AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [
AC_LINK_IFELSE([AC_LANG_PROGRAM([
m4_case([$1],
[alias], [
int foo( void ) { return 0; }
int bar( void ) __attribute__(($1("foo")));
],
[aligned], [
int foo( void ) __attribute__(($1(32)));
],
[alloc_size], [
void *foo(int a) __attribute__(($1(1)));
],
[always_inline], [
inline __attribute__(($1)) int foo( void ) { return 0; }
],
[artificial], [
inline __attribute__(($1)) int foo( void ) { return 0; }
],
[cold], [
int foo( void ) __attribute__(($1));
],
[const], [
int foo( void ) __attribute__(($1));
],
[constructor_priority], [
int foo( void ) __attribute__((__constructor__(65535/2)));
],
[constructor], [
int foo( void ) __attribute__(($1));
],
[deprecated], [
int foo( void ) __attribute__(($1("")));
],
[destructor], [
int foo( void ) __attribute__(($1));
],
[dllexport], [
__attribute__(($1)) int foo( void ) { return 0; }
],
[dllimport], [
int foo( void ) __attribute__(($1));
],
[error], [
int foo( void ) __attribute__(($1("")));
],
[externally_visible], [
int foo( void ) __attribute__(($1));
],
[fallthrough], [
int foo( void ) {switch (0) { case 1: __attribute__(($1)); case 2: break ; }};
],
[flatten], [
int foo( void ) __attribute__(($1));
],
[format], [
int foo(const char *p, ...) __attribute__(($1(printf, 1, 2)));
],
[gnu_format], [
int foo(const char *p, ...) __attribute__((format(gnu_printf, 1, 2)));
],
[format_arg], [
char *foo(const char *p) __attribute__(($1(1)));
],
[gnu_inline], [
inline __attribute__(($1)) int foo( void ) { return 0; }
],
[hot], [
int foo( void ) __attribute__(($1));
],
[ifunc], [
int my_foo( void ) { return 0; }
static int (*resolve_foo(void))(void) { return my_foo; }
int foo( void ) __attribute__(($1("resolve_foo")));
],
[leaf], [
__attribute__(($1)) int foo( void ) { return 0; }
],
[malloc], [
void *foo( void ) __attribute__(($1));
],
[noclone], [
int foo( void ) __attribute__(($1));
],
[noinline], [
__attribute__(($1)) int foo( void ) { return 0; }
],
[nonnull], [
int foo(char *p) __attribute__(($1(1)));
],
[noreturn], [
void foo( void ) __attribute__(($1));
],
[nothrow], [
int foo( void ) __attribute__(($1));
],
[optimize], [
__attribute__(($1(3))) int foo( void ) { return 0; }
],
[pure], [
int foo( void ) __attribute__(($1));
],
[sentinel], [
int foo(void *p, ...) __attribute__(($1));
],
[sentinel_position], [
int foo(void *p, ...) __attribute__(($1(1)));
],
[returns_nonnull], [
void *foo( void ) __attribute__(($1));
],
[unused], [
int foo( void ) __attribute__(($1));
],
[used], [
int foo( void ) __attribute__(($1));
],
[visibility], [
int foo_def( void ) __attribute__(($1("default")));
int foo_hid( void ) __attribute__(($1("hidden")));
int foo_int( void ) __attribute__(($1("internal")));
int foo_pro( void ) __attribute__(($1("protected")));
],
[warning], [
int foo( void ) __attribute__(($1("")));
],
[warn_unused_result], [
int foo( void ) __attribute__(($1));
],
[weak], [
int foo( void ) __attribute__(($1));
],
[weakref], [
static int foo( void ) { return 0; }
static int bar( void ) __attribute__(($1("foo")));
],
[
m4_warn([syntax], [Unsupported attribute $1, the test may fail])
int foo( void ) __attribute__(($1));
]
)], [])
],
dnl GCC doesn't exit with an error if an unknown attribute is
dnl provided but only outputs a warning, so accept the attribute
dnl only if no warning were issued.
[AS_IF([grep -- -Wattributes conftest.err],
[AS_VAR_SET([ac_var], [no])],
[AS_VAR_SET([ac_var], [yes])])],
[AS_VAR_SET([ac_var], [no])])
])

AS_IF([test yes = AS_VAR_GET([ac_var])],
[AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1,
[Define to 1 if the system has the `$1' function attribute])], [])

AS_VAR_POPDEF([ac_var])
])