2008-06-07 Jan Kratochvil * configure.ac: Add check for HAVE_PERSONALITY. * configure, config.in: Regenerate. * fork-child.c: New include . [HAVE_PERSONALITY]: New include . [HAVE_PERSONALITY] (set_disable_randomization): New function. (disable_randomization, show_disable_randomization): New. (fork_inferior) [HAVE_PERSONALITY]: Disable randomization upon the variable DISABLE_RANDOMIZATION. (_initialize_fork_child): Call ADD_SETSHOW_BOOLEAN_CMD for the variable DISABLE_RANDOMIZATION. 2008-06-07 Jan Kratochvil * gdb.texinfo (Starting): Document "set disable-randomization". 2008-06-07 Jan Kratochvil * gdb.base/randomize.exp, gdb.base/randomize.c: New files. --- gdb/config.in 5 Jun 2008 22:36:56 -0000 1.100 +++ gdb/config.in 7 Jun 2008 18:37:52 -0000 @@ -237,6 +237,9 @@ /* Define to 1 if you have the header file. */ #undef HAVE_NLIST_H +/* Define if you support the personality syscall. */ +#undef HAVE_PERSONALITY + /* Define to 1 if you have the `poll' function. */ #undef HAVE_POLL --- gdb/configure 5 Jun 2008 22:36:56 -0000 1.249 +++ gdb/configure 7 Jun 2008 18:38:03 -0000 @@ -26702,6 +26702,108 @@ _ACEOF fi +if test "$cross_compiling" = yes; then + cat >conftest.$ac_ext <<_ACEOF +/* confdefs.h. */ +_ACEOF +cat confdefs.h >>conftest.$ac_ext +cat >>conftest.$ac_ext <<_ACEOF +/* end confdefs.h. */ +#include +int +main () +{ +#define PERSONALITY_ADDR_NO_RANDOMIZE 0x0040000 + /* Test the flag could be set and stays set. */ + personality (personality (0xffffffff) | PERSONALITY_ADDR_NO_RANDOMIZE); + if (!(personality (personality (0xffffffff)) + & PERSONALITY_ADDR_NO_RANDOMIZE)) + return 1 + ; + return 0; +} +_ACEOF +rm -f conftest.$ac_objext conftest$ac_exeext +if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5 + (eval $ac_link) 2>conftest.er1 + ac_status=$? + grep -v '^ *+' conftest.er1 >conftest.err + rm -f conftest.er1 + cat conftest.err >&5 + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); } && + { ac_try='test -z "$ac_c_werror_flag" + || test ! -s conftest.err' + { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5 + (eval $ac_try) 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); }; } && + { ac_try='test -s conftest$ac_exeext' + { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5 + (eval $ac_try) 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); }; }; then + +cat >>confdefs.h <<\_ACEOF +#define HAVE_PERSONALITY 1 +_ACEOF + +else + echo "$as_me: failed program was:" >&5 +sed 's/^/| /' conftest.$ac_ext >&5 + +fi +rm -f conftest.err conftest.$ac_objext \ + conftest$ac_exeext conftest.$ac_ext +else + cat >conftest.$ac_ext <<_ACEOF +/* confdefs.h. */ +_ACEOF +cat confdefs.h >>conftest.$ac_ext +cat >>conftest.$ac_ext <<_ACEOF +/* end confdefs.h. */ +#include +int +main () +{ +#define PERSONALITY_ADDR_NO_RANDOMIZE 0x0040000 + /* Test the flag could be set and stays set. */ + personality (personality (0xffffffff) | PERSONALITY_ADDR_NO_RANDOMIZE); + if (!(personality (personality (0xffffffff)) + & PERSONALITY_ADDR_NO_RANDOMIZE)) + return 1 + ; + return 0; +} +_ACEOF +rm -f conftest$ac_exeext +if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5 + (eval $ac_link) 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); } && { ac_try='./conftest$ac_exeext' + { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5 + (eval $ac_try) 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); }; }; then + +cat >>confdefs.h <<\_ACEOF +#define HAVE_PERSONALITY 1 +_ACEOF + +else + echo "$as_me: program exited with status $ac_status" >&5 +echo "$as_me: failed program was:" >&5 +sed 's/^/| /' conftest.$ac_ext >&5 + +fi +rm -f core *.core gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext +fi + + # Check whether --with-sysroot or --without-sysroot was given. if test "${with_sysroot+set}" = set; then --- gdb/configure.ac 5 Jun 2008 22:36:56 -0000 1.69 +++ gdb/configure.ac 7 Jun 2008 18:38:04 -0000 @@ -1266,6 +1266,23 @@ if test "x$gdb_cv_sys_syscall_h_has_tkil AC_DEFINE(HAVE_TKILL_SYSCALL, 1, [Define if you support the tkill syscall.]) fi +dnl Check if we can disable the virtual address space randomization. +dnl The functionality of setarch -R. +define([PERSONALITY_TEST], [AC_LANG_PROGRAM([#include ], + [#define PERSONALITY_ADDR_NO_RANDOMIZE 0x0040000 + /* Test the flag could be set and stays set. */ + personality (personality (0xffffffff) | PERSONALITY_ADDR_NO_RANDOMIZE); + if (!(personality (personality (0xffffffff)) + & PERSONALITY_ADDR_NO_RANDOMIZE)) + return 1])]) +AC_RUN_IFELSE(PERSONALITY_TEST, + AC_DEFINE([HAVE_PERSONALITY], 1, + [Define if you support the personality syscall.]), + , + AC_LINK_IFELSE(PERSONALITY_TEST, + AC_DEFINE([HAVE_PERSONALITY], 1, + [Define if you support the personality syscall.]))) + dnl Handle optional features that can be enabled. AC_ARG_WITH(sysroot, --- gdb/fork-child.c 15 Mar 2008 14:55:21 -0000 1.41 +++ gdb/fork-child.c 7 Jun 2008 18:38:11 -0000 @@ -35,6 +35,10 @@ #include "solib.h" #include +#include +#ifdef HAVE_PERSONALITY +# include +#endif /* This just gets used as a default if we can't find SHELL. */ #define SHELL_FILE "/bin/sh" @@ -42,6 +46,34 @@ extern char **environ; static char *exec_wrapper; +static int disable_randomization = +#ifdef HAVE_PERSONALITY + 1; +#else + 0; +#endif + +#ifndef HAVE_PERSONALITY +static void +set_disable_randomization (char *args, int from_tty, struct cmd_list_element *c) +{ + if (disable_randomization) + { + disable_randomization = 0; + error (_("Unsupported on this platform.")); + } +} +#endif + +static void +show_disable_randomization (struct ui_file *file, int from_tty, + struct cmd_list_element *c, const char *value) +{ + fprintf_filtered (file, _("\ +Whether we disable the randomization of the virtual address space of\n\ +a spawned child is %s.\n"), + value); +} /* Break up SCRATCH into an argument vector suitable for passing to execvp and store it in ARGV. E.g., on "run a b c d" this routine @@ -303,6 +335,23 @@ fork_inferior (char *exec_file_arg, char if (debug_fork) sleep (debug_fork); +#ifdef HAVE_PERSONALITY + if (disable_randomization) + { +# define PERSONALITY_ADDR_NO_RANDOMIZE 0x0040000 + int val; + + errno = 0; + val = personality (0xffffffff); + if (errno == 0) + personality (val | PERSONALITY_ADDR_NO_RANDOMIZE); + if (errno != 0 + || !(personality (0xffffffff) & PERSONALITY_ADDR_NO_RANDOMIZE)) + warning (_("Currently enabled disable-randomization is unsupported " + "on this platform.")); + } +#endif /* HAVE_PERSONALITY */ + /* Create a new session for the inferior process, if necessary. It will also place the inferior in a separate process group. */ if (create_tty_session () <= 0) @@ -490,4 +539,19 @@ Show the wrapper for running programs.") add_cmd ("exec-wrapper", class_run, unset_exec_wrapper_command, _("Disable use of an execution wrapper."), &unsetlist); + + add_setshow_boolean_cmd ("disable-randomization", class_support, + &disable_randomization, _("\ +Set mode for inserting breakpoints."), _("\ +Show mode for inserting breakpoints."), _("\ +When this mode is on (which is the default), the randomization of\n\ +the virtual address space is disabled (turns on ADDR_NO_RANDOMIZE).\n\ +Standalone programs run with the randomization enabled by default."), +#ifdef HAVE_PERSONALITY + NULL, +#else + set_disable_randomization, +#endif + &show_disable_randomization, + &setlist, &showlist); } --- gdb/doc/gdb.texinfo 6 Jun 2008 20:58:08 -0000 1.503 +++ gdb/doc/gdb.texinfo 7 Jun 2008 18:38:48 -0000 @@ -1999,6 +1999,38 @@ environment: This command is available when debugging locally on most targets, excluding @sc{djgpp}, Cygwin, MS Windows, and QNX Neutrino. +@kindex set disable-randomization +@item set disable-randomization +@itemx set disable-randomization on +This option (enabled by default in @value{GDBN}) will turn off the native +randomization of the virtual address space of the started program. This option +is useful for multiple debugging sessions to make the execution better +reproducible and memory addresses reusable across debugging sessions. + +This feature is implemented only on @sc{gnu}/Linux. You can get the same +behavior using + +@smallexample +(@value{GDBP}) set exec-wrapper setarch `uname -m` -R +@end smallexample + +@item set disable-randomization off +Leave the behavior of the started executable unchanged. While the addresses +get assigned differently on each run some subtle bugs may be reproducible only +with specially assigned addresses possibly not reachable with the default +setting of @kbd{set disable-randomization on}. + +PIE executables (type @code{ET_DYN}, compiled by @code{gcc -fPIE -pie}) have +randomized everything - the executable base address, shared libraries base +address (their prelinking is ignored), mmap areas, stack and heap. Regular +executables (type @code{ET_EXEC}) do not have randomized their base address, +shared libraries base address is ranomized only for non-prelinked libraries, +mmap, stack and heap are still randomized. + +@item show disable-randomization +Show the current setting of the explicit disable of the native randomization of +the virtual address space of the started program. + @end table @node Arguments --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ gdb/testsuite/gdb.base/randomize.c 7 Jun 2008 18:38:48 -0000 @@ -0,0 +1,32 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2008 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + + Please email any bugs, comments, and/or additions to this file to: + bug-gdb@prep.ai.mit.edu */ + +#include +#include + +int main() +{ + void *p; + + p = malloc (1); + printf ("address = %p\n", p); + + return 0; +} --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ gdb/testsuite/gdb.base/randomize.exp 7 Jun 2008 18:38:48 -0000 @@ -0,0 +1,63 @@ +# Copyright 2008 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +set testfile randomize +set srcfile ${testfile}.c +set binfile ${objdir}/${subdir}/${testfile} +if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { + untested "Couldn't compile test program" + return -1 +} + +# Get things started. + +gdb_exit +gdb_start +gdb_reinitialize_dir $srcdir/$subdir +gdb_load ${binfile} + +proc address_get { testname } { + global gdb_prompt + + if {![runto_main]} { + return -1 + } + gdb_test_multiple "continue" $testname { + -re "address = (0x\[0-9a-f\]*).*Program exited normally..*$gdb_prompt $" { + pass $testname + return $expect_out(1,string) + } + } +} + +gdb_test "set disable-randomization off" +set addr1 [address_get "randomized first address"] +set addr2 [address_get "randomized second address"] +set test "randomized addresses should not match" +if {$addr1 eq $addr2} { + fail $test +} else { + pass $test +} + +gdb_test "set disable-randomization on" +set addr1 [address_get "fixed first address"] +set addr2 [address_get "fixed second address"] +set test "fixed addresses should match" +if {$addr1 eq $addr2} { + pass $test +} else { + fail $test +}