C++: handle glibc's ptrace(enum __ptrace_request, ...)

Building in C++ mode issues ~40 warnings like this:

 ../../src/gdb/linux-nat.c: In function ‘int linux_handle_extended_wait(lwp_info*, int, int)’:
 ../../src/gdb/linux-nat.c:2016:51: warning: invalid conversion from ‘int’ to ‘__ptrace_request’ [-fpermissive]
	ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);

The issue is that in glibc, ptrace's first parameter is an enum.
That's not a problem if we pick the PTRACE_XXX requests from
sys/ptrace.h, as those will be values of the corresponding enum.
However, we have fallback definitions for PTRACE_XXX symbols when the
system headers miss them (such as PTRACE_GETEVENTMSG above), and those
are plain integer constants.  E.g., nat/linux-ptrace.h:

 #define PTRACE_GETEVENTMSG	0x4201

One idea would be to fix this by defining those fallbacks like:

 -#define PTRACE_GETEVENTMSG	0x4201
 +#define PTRACE_GETEVENTMSG	((enum __ptrace_request) 0x4201)

However, while glibc's ptrace uses enum __ptrace_request for first
parameter:

  extern long int ptrace (enum __ptrace_request __request, ...) __THROW;

other libc's, like e.g., Android's bionic do not -- in that case, the
first parameter is int:

  long ptrace(int request, pid_t pid, void * addr, void * data);

So the fix I came up is to make configure/ptrace.m4 also detect the
type of the ptrace's first parameter and defin PTRACE_TYPE_ARG1, as
already does the for parameters 3-4, and then simply wrap ptrace with
a macro that casts the first argument to the detected type.  (I'm
leaving adding a nicer wrapper for when we drop building in C).

While this adds the wrapper, GNU/Linux files won't use it until the
next patch, which makes all native GNU/Linux files include
gdb_ptrace.h.

gdb/ChangeLog:
2015-07-24  Pedro Alves  <palves@redhat.com>

	* ptrace.m4 (ptrace tests): Test in C++ mode.  Try with 'enum
	__ptrace_request as first parameter type instead of int.
	(PTRACE_TYPE_ARG1): Define.
	* nat/gdb_ptrace.h [!PTRACE_TYPE_ARG5] (ptrace): Define as wrapper
	that casts first argument to PTRACE_TYPE_ARG1.
	* config.in: Regenerate.
	* configure: Regenerate.

gdb/gdbserver/ChangeLog:
2015-07-24  Pedro Alves  <palves@redhat.com>

	* config.in: Regenerate.
	* configure: Regenerate.
This commit is contained in:
Pedro Alves 2015-07-24 14:57:20 +01:00
parent e379037592
commit 5401971915
8 changed files with 215 additions and 21 deletions

View file

@ -1,3 +1,13 @@
2015-07-24 Pedro Alves <palves@redhat.com>
* ptrace.m4 (ptrace tests): Test in C++ mode. Try with 'enum
__ptrace_request as first parameter type instead of int.
(PTRACE_TYPE_ARG1): Define.
* nat/gdb_ptrace.h [!PTRACE_TYPE_ARG5] (ptrace): Define as wrapper
that casts first argument to PTRACE_TYPE_ARG1.
* config.in: Regenerate.
* configure: Regenerate.
2015-07-24 Pedro Alves <palves@redhat.com>
* gdb_ptrace.h: Move ...

View file

@ -653,6 +653,9 @@
assorted other type changes. */
#undef PROC_SERVICE_IS_OLD
/* Define to the type of arg 1 for ptrace. */
#undef PTRACE_TYPE_ARG1
/* Define to the type of arg 3 for ptrace. */
#undef PTRACE_TYPE_ARG3

109
gdb/configure vendored
View file

@ -2398,6 +2398,51 @@ $as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_c_check_member
# ac_fn_cxx_check_decl LINENO SYMBOL VAR
# --------------------------------------
# Tests whether SYMBOL is declared, setting cache variable VAR accordingly.
ac_fn_cxx_check_decl ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
as_decl_name=`echo $2|sed 's/ *(.*//'`
as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
#ifndef $as_decl_name
#ifdef __cplusplus
(void) $as_decl_use;
#else
(void) $as_decl_name;
#endif
#endif
;
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
eval "$3=yes"
else
eval "$3=no"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
eval ac_res=\$$3
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_cxx_check_decl
cat >config.log <<_ACEOF
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.
@ -11926,8 +11971,36 @@ $as_echo "#define HAVE_SIGSETJMP 1" >>confdefs.h
fi
# Check the return and argument types of ptrace. No canned test for
# this, so roll our own.
# Check the return and argument types of ptrace.
for ac_header in sys/ptrace.h ptrace.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
eval as_val=\$$as_ac_Header
if test "x$as_val" = x""yes; then :
cat >>confdefs.h <<_ACEOF
#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
_ACEOF
fi
done
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -11938,7 +12011,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@ -11976,7 +12049,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -11990,7 +12063,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@ -12024,8 +12097,8 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='int,int,long,long'
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
for gdb_arg1 in 'int' 'long'; do
@ -12046,7 +12119,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@ -12066,7 +12139,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@ -12090,6 +12163,11 @@ set dummy `echo "$gdb_cv_func_ptrace_args" | sed 's/\*/\*/g'`
IFS=$ac_save_IFS
shift
cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG1 $1
_ACEOF
cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG3 $3
_ACEOF
@ -12107,6 +12185,16 @@ _ACEOF
fi
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
fi
if test "$cross_compiling" = no; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether setpgrp takes no argument" >&5
$as_echo_n "checking whether setpgrp takes no argument... " >&6; }
@ -13925,8 +14013,7 @@ $as_echo_n "checking compiler warning flags... " >&6; }
CFLAGS="$CFLAGS $w"
saved_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $w"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int

View file

@ -1,3 +1,8 @@
2015-07-24 Pedro Alves <palves@redhat.com>
* config.in: Regenerate.
* configure: Regenerate.
2015-07-24 Pedro Alves <palves@redhat.com>
* acinclude.m4: Include ../ptrace.m4.

View file

@ -310,6 +310,9 @@
/* Additional package description */
#undef PKGVERSION
/* Define to the type of arg 1 for ptrace. */
#undef PTRACE_TYPE_ARG1
/* Define to the type of arg 3 for ptrace. */
#undef PTRACE_TYPE_ARG3

View file

@ -1878,6 +1878,51 @@ $as_echo "$ac_res" >&6; }
} # ac_fn_c_check_decl
# ac_fn_cxx_check_decl LINENO SYMBOL VAR
# --------------------------------------
# Tests whether SYMBOL is declared, setting cache variable VAR accordingly.
ac_fn_cxx_check_decl ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
as_decl_name=`echo $2|sed 's/ *(.*//'`
as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
#ifndef $as_decl_name
#ifdef __cplusplus
(void) $as_decl_use;
#else
(void) $as_decl_name;
#endif
#endif
;
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
eval "$3=yes"
else
eval "$3=no"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
eval ac_res=\$$3
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_cxx_check_decl
# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
# -------------------------------------------
# Tests whether TYPE exists after having included INCLUDES, setting cache
@ -5751,6 +5796,7 @@ fi
# Check the return and argument types of ptrace.
for ac_header in sys/ptrace.h ptrace.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@ -5766,6 +5812,17 @@ fi
done
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -5776,7 +5833,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@ -5814,7 +5871,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -5828,7 +5885,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@ -5862,8 +5919,8 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='int,int,long,long'
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
for gdb_arg1 in 'int' 'long'; do
@ -5884,7 +5941,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@ -5904,7 +5961,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@ -5928,6 +5985,11 @@ set dummy `echo "$gdb_cv_func_ptrace_args" | sed 's/\*/\*/g'`
IFS=$ac_save_IFS
shift
cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG1 $1
_ACEOF
cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG3 $3
_ACEOF
@ -5945,6 +6007,15 @@ _ACEOF
fi
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
fi
# Check for UST
ustlibs=""
@ -6087,8 +6158,7 @@ $as_echo_n "checking compiler warning flags... " >&6; }
CFLAGS="$CFLAGS $w"
saved_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $w"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int

View file

@ -144,6 +144,10 @@ extern PTRACE_TYPE_RET ptrace();
# define ptrace(request, pid, addr, data) \
ptrace (request, pid, addr, data, 0)
# endif
#else
/* Wrapper that avoids adding a pointless cast to all callers. */
# define ptrace(request, pid, addr, data) \
ptrace ((PTRACE_TYPE_ARG1) request, pid, addr, data)
#endif
#endif /* gdb_ptrace.h */

View file

@ -22,6 +22,12 @@ AC_DEFUN([GDB_AC_PTRACE],
AC_CHECK_HEADERS([sys/ptrace.h ptrace.h])
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
AC_LANG_PUSH([C++])
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -52,7 +58,7 @@ AC_DEFINE_UNQUOTED(PTRACE_TYPE_RET, $gdb_cv_func_ptrace_ret,
AC_CACHE_CHECK([types of arguments for ptrace], gdb_cv_func_ptrace_args, [
AC_TRY_COMPILE($gdb_ptrace_headers,
[extern long ptrace (enum __ptrace_request, ...);],
[gdb_cv_func_ptrace_args='int,int,long,long'],[
[gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'],[
for gdb_arg1 in 'int' 'long'; do
for gdb_arg2 in 'pid_t' 'int' 'long'; do
for gdb_arg3 in 'int *' 'caddr_t' 'int' 'long' 'void *'; do
@ -81,6 +87,8 @@ ac_save_IFS=$IFS; IFS=','
set dummy `echo "$gdb_cv_func_ptrace_args" | sed 's/\*/\*/g'`
IFS=$ac_save_IFS
shift
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG1, $[1],
[Define to the type of arg 1 for ptrace.])
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG3, $[3],
[Define to the type of arg 3 for ptrace.])
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG4, $[4],
@ -89,4 +97,8 @@ if test -n "$[5]"; then
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG5, $[5],
[Define to the type of arg 5 for ptrace.])
fi
if test "$enable_build_with_cxx" = "yes"; then
AC_LANG_POP([C++])
fi
])