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Fix gdbserver build failure on targets without fork 

This commit fixes nat/linux-namespaces.c to build correctly on
targets without fork.

gdb/ChangeLog:

	* nat/linux-namespaces.c (do_fork): New function.
	(linux_mntns_get_helper): Use the above.

gdb/gdbserver/ChangeLog:

	* configure.ac (AC_FUNC_FORK): New check.
	* config.in: Regenerate.
	* configure: Likewise.
This commit is contained in:
Gary Benson 2016-01-18 09:45:10 +00:00
parent 760f6ee894
commit eb0edac83f
6 changed files with 326 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gdb/ChangeLog
View File

@ -1,3 +1,8 @@
2016-01-18 Gary Benson <gbenson@redhat.com>
* nat/linux-namespaces.c (do_fork): New function.
(linux_mntns_get_helper): Use the above.
2016-01-17 Jonas Hahnfeld <Hahnfeld@itc.rwth-aachen.de> (tiny change)
Pushed by Joel Brobecker <brobecker@adacore.com>.

6
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,9 @@
2016-01-18 Gary Benson <gbenson@redhat.com>
* configure.ac (AC_FUNC_FORK): New check.
* config.in: Regenerate.
* configure: Likewise.
2016-01-14 Yao Qi <yao.qi@linaro.org>
* linux-aarch32-low.c (thumb2_breakpoint): Make it static.

21
gdb/gdbserver/config.in
View File

@ -99,6 +99,9 @@
/* Define to 1 if you have the `fdwalk' function. */
#undef HAVE_FDWALK
/* Define to 1 if you have the `fork' function. */
#undef HAVE_FORK
/* Define to 1 if you have the `getauxval' function. */
#undef HAVE_GETAUXVAL
@ -286,9 +289,21 @@
/* Define if UST is available */
#undef HAVE_UST
/* Define to 1 if you have the `vfork' function. */
#undef HAVE_VFORK
/* Define to 1 if you have the <vfork.h> header file. */
#undef HAVE_VFORK_H
/* Define to 1 if you have the <wait.h> header file. */
#undef HAVE_WAIT_H
/* Define to 1 if `fork' works. */
#undef HAVE_WORKING_FORK
/* Define to 1 if `vfork' works. */
#undef HAVE_WORKING_VFORK
/* Define to the address where bug reports for this package should be sent. */
#undef PACKAGE_BUGREPORT
@ -393,3 +408,9 @@
/* Define to 1 if you need to in order for `stat' and other things to work. */
#undef _POSIX_SOURCE
/* Define to `int' if <sys/types.h> does not define. */
#undef pid_t
/* Define as `fork' if `vfork' does not work. */
#undef vfork

333
gdb/gdbserver/configure vendored
View File

@ -1772,6 +1772,60 @@ fi
} # ac_fn_c_try_link
# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
# -------------------------------------------
# Tests whether TYPE exists after having included INCLUDES, setting cache
# variable VAR accordingly.
ac_fn_c_check_type ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
$as_echo_n "checking for $2... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
eval "$3=no"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
if (sizeof ($2))
return 0;
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
if (sizeof (($2)))
return 0;
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
else
eval "$3=yes"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
rm -f core conftest.err conftest.$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_c_check_type
# ac_fn_c_check_func LINENO FUNC VAR
# ----------------------------------
# Tests whether FUNC exists, setting the cache variable VAR accordingly
@ -1929,60 +1983,6 @@ $as_echo "$ac_res" >&6; }
} # ac_fn_cxx_check_decl
# ac_fn_c_check_type LINENO TYPE VAR INCLUDES
# -------------------------------------------
# Tests whether TYPE exists after having included INCLUDES, setting cache
# variable VAR accordingly.
ac_fn_c_check_type ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
$as_echo_n "checking for $2... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
eval "$3=no"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
if (sizeof ($2))
return 0;
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
if (sizeof (($2)))
return 0;
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
else
eval "$3=yes"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
rm -f core conftest.err conftest.$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_c_check_type
# ac_fn_c_compute_int LINENO EXPR VAR INCLUDES
# --------------------------------------------
# Tries to find the compile-time value of EXPR in a program that includes
@ -5360,6 +5360,231 @@ fi
done
ac_fn_c_check_type "$LINENO" "pid_t" "ac_cv_type_pid_t" "$ac_includes_default"
if test "x$ac_cv_type_pid_t" = x""yes; then :
else
cat >>confdefs.h <<_ACEOF
#define pid_t int
_ACEOF
fi
for ac_header in vfork.h
do :
ac_fn_c_check_header_mongrel "$LINENO" "vfork.h" "ac_cv_header_vfork_h" "$ac_includes_default"
if test "x$ac_cv_header_vfork_h" = x""yes; then :
cat >>confdefs.h <<_ACEOF
#define HAVE_VFORK_H 1
_ACEOF
fi
done
for ac_func in fork vfork
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
eval as_val=\$$as_ac_var
if test "x$as_val" = x""yes; then :
cat >>confdefs.h <<_ACEOF
#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
_ACEOF
fi
done
if test "x$ac_cv_func_fork" = xyes; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for working fork" >&5
$as_echo_n "checking for working fork... " >&6; }
if test "${ac_cv_func_fork_works+set}" = set; then :
$as_echo_n "(cached) " >&6
else
if test "$cross_compiling" = yes; then :
ac_cv_func_fork_works=cross
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$ac_includes_default
int
main ()
{
/* By Ruediger Kuhlmann. */
return fork () < 0;
;
return 0;
}
_ACEOF
if ac_fn_c_try_run "$LINENO"; then :
ac_cv_func_fork_works=yes
else
ac_cv_func_fork_works=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_fork_works" >&5
$as_echo "$ac_cv_func_fork_works" >&6; }
else
ac_cv_func_fork_works=$ac_cv_func_fork
fi
if test "x$ac_cv_func_fork_works" = xcross; then
case $host in
*-*-amigaos* | *-*-msdosdjgpp*)
# Override, as these systems have only a dummy fork() stub
ac_cv_func_fork_works=no
;;
*)
ac_cv_func_fork_works=yes
;;
esac
{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: result $ac_cv_func_fork_works guessed because of cross compilation" >&5
$as_echo "$as_me: WARNING: result $ac_cv_func_fork_works guessed because of cross compilation" >&2;}
fi
ac_cv_func_vfork_works=$ac_cv_func_vfork
if test "x$ac_cv_func_vfork" = xyes; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for working vfork" >&5
$as_echo_n "checking for working vfork... " >&6; }
if test "${ac_cv_func_vfork_works+set}" = set; then :
$as_echo_n "(cached) " >&6
else
if test "$cross_compiling" = yes; then :
ac_cv_func_vfork_works=cross
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
/* Thanks to Paul Eggert for this test. */
$ac_includes_default
#include <sys/wait.h>
#ifdef HAVE_VFORK_H
# include <vfork.h>
#endif
/* On some sparc systems, changes by the child to local and incoming
argument registers are propagated back to the parent. The compiler
is told about this with #include <vfork.h>, but some compilers
(e.g. gcc -O) don't grok <vfork.h>. Test for this by using a
static variable whose address is put into a register that is
clobbered by the vfork. */
static void
#ifdef __cplusplus
sparc_address_test (int arg)
# else
sparc_address_test (arg) int arg;
#endif
{
static pid_t child;
if (!child) {
child = vfork ();
if (child < 0) {
perror ("vfork");
_exit(2);
}
if (!child) {
arg = getpid();
write(-1, "", 0);
_exit (arg);
}
}
}
int
main ()
{
pid_t parent = getpid ();
pid_t child;
sparc_address_test (0);
child = vfork ();
if (child == 0) {
/* Here is another test for sparc vfork register problems. This
test uses lots of local variables, at least as many local
variables as main has allocated so far including compiler
temporaries. 4 locals are enough for gcc 1.40.3 on a Solaris
4.1.3 sparc, but we use 8 to be safe. A buggy compiler should
reuse the register of parent for one of the local variables,
since it will think that parent can't possibly be used any more
in this routine. Assigning to the local variable will thus
munge parent in the parent process. */
pid_t
p = getpid(), p1 = getpid(), p2 = getpid(), p3 = getpid(),
p4 = getpid(), p5 = getpid(), p6 = getpid(), p7 = getpid();
/* Convince the compiler that p..p7 are live; otherwise, it might
use the same hardware register for all 8 local variables. */
if (p != p1 || p != p2 || p != p3 || p != p4
|| p != p5 || p != p6 || p != p7)
_exit(1);
/* On some systems (e.g. IRIX 3.3), vfork doesn't separate parent
from child file descriptors. If the child closes a descriptor
before it execs or exits, this munges the parent's descriptor
as well. Test for this by closing stdout in the child. */
_exit(close(fileno(stdout)) != 0);
} else {
int status;
struct stat st;
while (wait(&status) != child)
;
return (
/* Was there some problem with vforking? */
child < 0
/* Did the child fail? (This shouldn't happen.) */
|| status
/* Did the vfork/compiler bug occur? */
|| parent != getpid()
/* Did the file descriptor bug occur? */
|| fstat(fileno(stdout), &st) != 0
);
}
}
_ACEOF
if ac_fn_c_try_run "$LINENO"; then :
ac_cv_func_vfork_works=yes
else
ac_cv_func_vfork_works=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_vfork_works" >&5
$as_echo "$ac_cv_func_vfork_works" >&6; }
fi;
if test "x$ac_cv_func_fork_works" = xcross; then
ac_cv_func_vfork_works=$ac_cv_func_vfork
{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: result $ac_cv_func_vfork_works guessed because of cross compilation" >&5
$as_echo "$as_me: WARNING: result $ac_cv_func_vfork_works guessed because of cross compilation" >&2;}
fi
if test "x$ac_cv_func_vfork_works" = xyes; then
$as_echo "#define HAVE_WORKING_VFORK 1" >>confdefs.h
else
$as_echo "#define vfork fork" >>confdefs.h
fi
if test "x$ac_cv_func_fork_works" = xyes; then
$as_echo "#define HAVE_WORKING_FORK 1" >>confdefs.h
fi
for ac_func in getauxval pread pwrite pread64 setns
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`

1
gdb/gdbserver/configure.ac
View File

@ -94,6 +94,7 @@ AC_CHECK_HEADERS(sgtty.h termio.h termios.h sys/reg.h string.h dnl
fcntl.h signal.h sys/file.h dnl
sys/ioctl.h netinet/in.h sys/socket.h netdb.h dnl
netinet/tcp.h arpa/inet.h)
AC_FUNC_FORK
AC_CHECK_FUNCS(getauxval pread pwrite pread64 setns)
GDB_AC_COMMON

15
gdb/nat/linux-namespaces.c
View File

@ -32,6 +32,19 @@
/* See nat/linux-namespaces.h. */
int debug_linux_namespaces;
/* Handle systems without fork. */
static inline pid_t
do_fork (void)
{
#ifdef HAVE_FORK
return fork ();
#else
errno = ENOSYS;
return -1;
#endif
}
/* Handle systems without setns. */
static inline int
@ -644,7 +657,7 @@ linux_mntns_get_helper (void)
if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, sv) < 0)
return NULL;
h.pid = fork ();
h.pid = do_fork ();
if (h.pid < 0)
{
int saved_errno = errno;