diff options
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/solib-svr4.c | 184 | ||||
| -rw-r--r-- | gdb/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.base/break-interp.exp | 413 |
4 files changed, 523 insertions, 88 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 8ed5d3b..ffcbe74 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2010-01-14 Jan Kratochvil <jan.kratochvil@redhat.com> + + * solib-svr4.c (svr4_relocate_main_executable): Move the static exec + code part to ... + (svr4_static_exec_displacement): ... a new function. + (svr4_exec_displacement): New function. + (svr4_relocate_main_executable): Call svr4_exec_displacement. Allocate + new_offsets using alloca now. Remove variable old_chain and changed. + Call objfile_relocate unconditionally now. + 2010-01-14 Doug Evans <dje@google.com> * gdbtypes.c (arch_flags_type): Fix comment. diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 00e16b0..3ad067a 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -1535,111 +1535,119 @@ svr4_special_symbol_handling (void) { } -/* Relocate the main executable. This function should be called upon - stopping the inferior process at the entry point to the program. - The entry point from BFD is compared to the PC and if they are - different, the main executable is relocated by the proper amount. +/* Decide if the objfile needs to be relocated. As indicated above, + we will only be here when execution is stopped at the beginning + of the program. Relocation is necessary if the address at which + we are presently stopped differs from the start address stored in + the executable AND there's no interpreter section. The condition + regarding the interpreter section is very important because if + there *is* an interpreter section, execution will begin there + instead. When there is an interpreter section, the start address + is (presumably) used by the interpreter at some point to start + execution of the program. + + If there is an interpreter, it is normal for it to be set to an + arbitrary address at the outset. The job of finding it is + handled in enable_break(). + + So, to summarize, relocations are necessary when there is no + interpreter section and the start address obtained from the + executable is different from the address at which GDB is + currently stopped. - As written it will only attempt to relocate executables which - lack interpreter sections. It seems likely that only dynamic - linker executables will get relocated, though it should work - properly for a position-independent static executable as well. */ + [ The astute reader will note that we also test to make sure that + the executable in question has the DYNAMIC flag set. It is my + opinion that this test is unnecessary (undesirable even). It + was added to avoid inadvertent relocation of an executable + whose e_type member in the ELF header is not ET_DYN. There may + be a time in the future when it is desirable to do relocations + on other types of files as well in which case this condition + should either be removed or modified to accomodate the new file + type. (E.g, an ET_EXEC executable which has been built to be + position-independent could safely be relocated by the OS if + desired. It is true that this violates the ABI, but the ABI + has been known to be bent from time to time.) - Kevin, Nov 2000. ] + */ -static void -svr4_relocate_main_executable (void) +static CORE_ADDR +svr4_static_exec_displacement (void) { asection *interp_sect; struct regcache *regcache = get_thread_arch_regcache (inferior_ptid, target_gdbarch); CORE_ADDR pc = regcache_read_pc (regcache); - /* Decide if the objfile needs to be relocated. As indicated above, - we will only be here when execution is stopped at the beginning - of the program. Relocation is necessary if the address at which - we are presently stopped differs from the start address stored in - the executable AND there's no interpreter section. The condition - regarding the interpreter section is very important because if - there *is* an interpreter section, execution will begin there - instead. When there is an interpreter section, the start address - is (presumably) used by the interpreter at some point to start - execution of the program. - - If there is an interpreter, it is normal for it to be set to an - arbitrary address at the outset. The job of finding it is - handled in enable_break(). - - So, to summarize, relocations are necessary when there is no - interpreter section and the start address obtained from the - executable is different from the address at which GDB is - currently stopped. - - [ The astute reader will note that we also test to make sure that - the executable in question has the DYNAMIC flag set. It is my - opinion that this test is unnecessary (undesirable even). It - was added to avoid inadvertent relocation of an executable - whose e_type member in the ELF header is not ET_DYN. There may - be a time in the future when it is desirable to do relocations - on other types of files as well in which case this condition - should either be removed or modified to accomodate the new file - type. (E.g, an ET_EXEC executable which has been built to be - position-independent could safely be relocated by the OS if - desired. It is true that this violates the ABI, but the ABI - has been known to be bent from time to time.) - Kevin, Nov 2000. ] - */ - interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); if (interp_sect == NULL && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0 && (exec_entry_point (exec_bfd, &exec_ops) != pc)) + return pc - exec_entry_point (exec_bfd, &exec_ops); + + return 0; +} + +/* We relocate all of the sections by the same amount. This + behavior is mandated by recent editions of the System V ABI. + According to the System V Application Binary Interface, + Edition 4.1, page 5-5: + + ... Though the system chooses virtual addresses for + individual processes, it maintains the segments' relative + positions. Because position-independent code uses relative + addressesing between segments, the difference between + virtual addresses in memory must match the difference + between virtual addresses in the file. The difference + between the virtual address of any segment in memory and + the corresponding virtual address in the file is thus a + single constant value for any one executable or shared + object in a given process. This difference is the base + address. One use of the base address is to relocate the + memory image of the program during dynamic linking. + + The same language also appears in Edition 4.0 of the System V + ABI and is left unspecified in some of the earlier editions. */ + +static CORE_ADDR +svr4_exec_displacement (void) +{ + int found; + CORE_ADDR entry_point; + + if (exec_bfd == NULL) + return 0; + + if (target_auxv_search (¤t_target, AT_ENTRY, &entry_point) == 1) + return entry_point - exec_entry_point (exec_bfd, ¤t_target); + + return svr4_static_exec_displacement (); +} + +/* Relocate the main executable. This function should be called upon + stopping the inferior process at the entry point to the program. + The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are + different, the main executable is relocated by the proper amount. */ + +static void +svr4_relocate_main_executable (void) +{ + CORE_ADDR displacement = svr4_exec_displacement (); + + /* Even if DISPLACEMENT is 0 still try to relocate it as this is a new + difference of in-memory vs. in-file addresses and we could already + relocate the executable at this function to improper address before. */ + + if (symfile_objfile) { - struct cleanup *old_chain; struct section_offsets *new_offsets; - int i, changed; - CORE_ADDR displacement; - - /* It is necessary to relocate the objfile. The amount to - relocate by is simply the address at which we are stopped - minus the starting address from the executable. - - We relocate all of the sections by the same amount. This - behavior is mandated by recent editions of the System V ABI. - According to the System V Application Binary Interface, - Edition 4.1, page 5-5: - - ... Though the system chooses virtual addresses for - individual processes, it maintains the segments' relative - positions. Because position-independent code uses relative - addressesing between segments, the difference between - virtual addresses in memory must match the difference - between virtual addresses in the file. The difference - between the virtual address of any segment in memory and - the corresponding virtual address in the file is thus a - single constant value for any one executable or shared - object in a given process. This difference is the base - address. One use of the base address is to relocate the - memory image of the program during dynamic linking. - - The same language also appears in Edition 4.0 of the System V - ABI and is left unspecified in some of the earlier editions. */ - - displacement = pc - exec_entry_point (exec_bfd, &exec_ops); - changed = 0; - - new_offsets = xcalloc (symfile_objfile->num_sections, - sizeof (struct section_offsets)); - old_chain = make_cleanup (xfree, new_offsets); + int i; - for (i = 0; i < symfile_objfile->num_sections; i++) - { - if (displacement != ANOFFSET (symfile_objfile->section_offsets, i)) - changed = 1; - new_offsets->offsets[i] = displacement; - } + new_offsets = alloca (symfile_objfile->num_sections + * sizeof (*new_offsets)); - if (changed) - objfile_relocate (symfile_objfile, new_offsets); + for (i = 0; i < symfile_objfile->num_sections; i++) + new_offsets->offsets[i] = displacement; - do_cleanups (old_chain); + objfile_relocate (symfile_objfile, new_offsets); } } diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 0d440c6..5caf2a9 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2010-01-14 Jan Kratochvil <jan.kratochvil@redhat.com> + + * gdb.base/break-interp.exp: New file. + 2010-01-13 Phil Muldoon <pmuldoon@redhat.com> * gdb.python/py-value.exp (test_lazy_strings): Add lazy string test. diff --git a/gdb/testsuite/gdb.base/break-interp.exp b/gdb/testsuite/gdb.base/break-interp.exp new file mode 100644 index 0000000..d225b6c --- /dev/null +++ b/gdb/testsuite/gdb.base/break-interp.exp @@ -0,0 +1,413 @@ +# Copyright 2010 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 <http://www.gnu.org/licenses/>. + +# This test only works on GNU/Linux. +if { ![isnative] || [is_remote host] || ![istarget *-linux*] } { + continue +} + +set test "break-interp" +set binprefix ${objdir}/${subdir}/${test} +# Only to get the $interp_system name. +set srcfile_test "start.c" +set binfile_test ${test}-test +set srcfile "start.c" +if {[build_executable ${test}.exp $binfile_test ${srcfile_test} {}] == -1} { + return -1 +} + +# Return the interpreter filename string. +# Return "" if no interpreter was found. +proc section_get {exec section} { + global objdir + global subdir + set tmp "${objdir}/${subdir}/break-interp.interp" + set objcopy_program [transform objcopy] + + set command "exec $objcopy_program -O binary --set-section-flags $section=A --change-section-address $section=0 -j $section $exec $tmp" + verbose -log "command is $command" + set result [catch $command output] + verbose -log "result is $result" + verbose -log "output is $output" + if {$result == 1} { + return "" + } + set fi [open $tmp] + fconfigure $fi -translation binary + set data [read $fi] + close $fi + #file delete $tmp + # .interp has size $len + 1 but .gnu_debuglink contains garbage after \000. + set len [string first \000 $data] + if {$len < 0} { + verbose -log "section $section not found" + return "" + } + set retval [string range $data 0 [expr $len - 1]] + verbose -log "section $section is <$retval>" + return $retval +} + +# Note: The separate debug info file content build-id/crc32 are not verified +# contrary to the GDB search algorithm skipping non-matching ones. +proc system_debug_get {exec} { + global debug_root + + set exec_build_id_debug [build_id_debug_filename_get $exec] + set debug_base "[file tail $exec].debug" + set exec_dir [file dirname $exec] + + # isfile returns 1 even for symlinks to files. + set retval $debug_root/$exec_build_id_debug + if [file isfile $retval] { + return $retval + } + set retval $exec_dir/$debug_base + if [file isfile $retval] { + return $retval + } + set retval $exec_dir/.debug/$debug_base + if [file isfile $retval] { + return $retval + } + set retval $debug_root/$exec_dir/$debug_base + if [file isfile $retval] { + return $retval + } + return "" +} + +gdb_exit +gdb_start +set debug_root "" +set test "show debug-file-directory" +gdb_test_multiple $test $test { + -re "The directory where separate debug symbols are searched for is \"(.*)\".\r\n$gdb_prompt $" { + set debug_root $expect_out(1,string) + } +} + +set interp_system [section_get ${objdir}/${subdir}/$binfile_test .interp] +set interp_system_debug [system_debug_get $interp_system] +verbose -log "$interp_system has debug $interp_system_debug" + +proc prelinkNO_run {arg} { + set command "exec /usr/sbin/prelink -uN $arg" + verbose -log "command is $command" + set result [catch $command output] + verbose -log "result is $result" + verbose -log "output is $output" + return [list $result $output] +} + +proc prelinkNO {arg {name {}}} { + if {$name == ""} { + set name [file tail $arg] + } + set test "unprelink $name" + set run [prelinkNO_run $arg] + set result [lindex $run 0] + set output [lindex $run 1] + if {$result == 0 && $output == ""} { + verbose -log "$name has been now unprelinked" + set run [prelinkNO_run $arg] + set result [lindex $run 0] + set output [lindex $run 1] + } + # Last line does miss the trailing \n. + if {$result == 1 && [regexp {^(/usr/sbin/prelink: [^ ]* does not have .gnu.prelink_undo section\n?)*$} $output]} { + pass $test + return 1 + } else { + fail $test + return 0 + } +} + +proc prelinkYES {arg {name ""}} { + if {$name == ""} { + set name [file tail $arg] + } + set test "prelink $name" + set command "exec /usr/sbin/prelink -qNR --no-exec-shield $arg" + verbose -log "command is $command" + set result [catch $command output] + verbose -log "result is $result" + verbose -log "output is $output" + if {$result == 0 && $output == ""} { + pass $test + return 1 + } else { + fail $test + return 0 + } +} + +# Resolve symlinks. +proc symlink_resolve {file} { + set loop 0 + while {[file type $file] == "link"} { + set target [file readlink $file] + if {[file pathtype $target] == "relative"} { + set src2 [file dirname $file]/$target + } else { + set src2 $target + } + verbose -log "Resolved symlink $file targetting $target as $src2" + set file $src2 + + set loop [expr $loop + 1] + if {$loop > 30} { + fail "Looping symlink resolution for $file" + return "" + } + } + return $file +} + +proc copy {src dest} { + set src [symlink_resolve $src] + # Test name would contain build-id hash for symlink-unresolved $src. + set test "copy [file tail $src] to [file tail $dest]" + set command "file copy -force $src $dest" + verbose -log "command is $command" + if [catch $command] { + fail $test + return 0 + } else { + pass $test + return 1 + } +} + +proc strip_debug {dest} { + set test "strip [file tail $dest]" + set strip_program [transform strip] + set command "exec $strip_program --strip-debug $dest" + verbose -log "command is $command" + if [catch $command] { + fail $test + return 0 + } else { + pass $test + return 1 + } +} + +# `runto' does not check we stopped really at the function we specified. +proc reach {func command} { + global gdb_prompt + + if [gdb_breakpoint $func allow-pending] { + set test "reach $func" + gdb_test_multiple $command $test { + -re "Breakpoint \[0-9\]+, $func \\(.*\\) at .*:\[0-9\]+\r\n.*$gdb_prompt $" { + pass $test + } + -re "Breakpoint \[0-9\]+, \[0-9xa-f\]+ in $func \\(\\)( from .*)?\r\n$gdb_prompt $" { + pass $test + } + } + } +} + +proc test_ld {file ifmain} { + global srcdir subdir gdb_prompt + + # First test normal `file'-command loaded $FILE with symbols. + + gdb_exit + gdb_start + # Clear it to never find any separate debug infos in $debug_root. + gdb_test "set debug-file-directory" + gdb_reinitialize_dir $srcdir/$subdir + gdb_load $file + + reach "dl_main" run + if $ifmain { + reach "main" continue + } +} + +# Create separate binaries for each testcase - to make the possible reported +# problem reproducible after the whole test run finishes. + +set old_ldprefix $pf_prefix +foreach ldprelink {NO YES} { + foreach ldsepdebug {NO IN SEP} { + # Skip running the ldsepdebug test if we do not have system separate + # debug info available. + if {$interp_system_debug == "" && $ldsepdebug == "SEP"} { + continue + } + + set ldname "LDprelink${ldprelink}debug${ldsepdebug}" + set interp $binprefix-$ldname + + # prelink needs to always prelink all the dependencies to do any file + # modifications of its files. ld.so also needs all the dependencies to + # be prelinked to omit the relocation process. In-memory file offsets + # are not dependent whether ld.so went the prelink way or through the + # relocation process. + # + # For GDB we are not interested whether prelink succeeds as it is + # transparent to GDB. GDB is being tested for differences of file + # offsets vs. in-memory offsets. So we have to prelink even ld.so for + # the BIN modification to happen but we need to restore the original + # possibly unprelinked ld.so to test all the combinations for GDB. + set interp_saved ${interp}-saved + + set pf_prefix $old_ldprefix + lappend pf_prefix "$ldname:" + + if {$ldsepdebug == "NO"} { + copy $interp_system $interp + # Never call strip-debug before unprelink: + # prelink: ...: Section .note.gnu.build-id created after prelinking + if ![prelinkNO $interp] { + continue + } + strip_debug $interp + } elseif {$ldsepdebug == "IN" && $interp_system_debug == ""} { + copy $interp_system $interp + } elseif {$ldsepdebug == "IN" && $interp_system_debug != ""} { + copy $interp_system $interp + copy $interp_system_debug "${interp}.debug" + # eu-unstrip: DWARF data in '...' not adjusted for prelinking bias; consider prelink -u + if {![prelinkNO $interp] || ![prelinkNO "${interp}.debug"]} { + continue + } + set test "eu-unstrip unprelinked:[file tail $interp_system] + [file tail $interp_system_debug] to [file tail $interp]" + set command "exec eu-unstrip -o $interp $interp ${interp}.debug" + verbose -log "command is $command" + if [catch $command] { + setup_xfail *-*-* + fail $test + continue + } else { + pass $test + } + } elseif {$ldsepdebug == "SEP" && $interp_system_debug == ""} { + copy $interp_system $interp + # eu-unstrip: DWARF data in '...' not adjusted for prelinking bias; consider prelink -u + if ![prelinkNO $interp] { + continue + } + gdb_gnu_strip_debug $interp + } elseif {$ldsepdebug == "SEP" && $interp_system_debug != ""} { + copy $interp_system $interp + copy $interp_system_debug "${interp}.debug" + } + + if {$ldsepdebug == "SEP"} { + if ![prelinkNO "${interp}.debug"] { + continue + } + } else { + file delete "${interp}.debug" + } + + if ![prelink$ldprelink $interp] { + continue + } + test_ld $interp 0 + + if ![copy $interp $interp_saved] { + continue + } + set old_binprefix $pf_prefix + foreach binprelink {NO YES} { + foreach binsepdebug {NO IN SEP} { + foreach binpie {NO YES} { + # This combination is not possible, non-PIE (fixed address) + # binary cannot be prelinked to any (other) address. + if {$binprelink == "YES" && $binpie == "NO"} { + continue + } + + set binname "BINprelink${binprelink}debug${binsepdebug}pie${binpie}" + set exec $binprefix-$binname + set dir ${exec}.d + + set pf_prefix $old_binprefix + lappend pf_prefix "$binname:" + + set opts "additional_flags=-Wl,--dynamic-linker,$interp,-rpath,$dir" + if {$binsepdebug != "NO"} { + lappend opts {debug} + } + if {$binpie == "YES"} { + lappend opts {additional_flags=-fPIE -pie} + } + if {[build_executable ${test}.exp [file tail $exec] $srcfile $opts] == -1} { + continue; + } + if {$binsepdebug == "SEP"} { + gdb_gnu_strip_debug $exec + # Just a sanity check. As gdb_gnu_strip_debug uses the + # "[file dirname $exec]/.debug/[file tail $exec].debug" + # variant delete the higher-priority exec.debug file. + file delete "$exec.debug" + } + + # Supply a self-sufficent directory $dir with the required + # libraries. To make an executable properly prelinked all + # its dependencies on libraries must be also prelinked. If + # some of the system libraries is currently not prelinked + # we have no right to prelink (modify it) at its current + # system place. + + file delete -force $dir + file mkdir $dir + + set command "ldd $exec" + set result [catch "exec $command" output] + verbose -log "result of $command is $result" + verbose -log "output of $command is $output" + if {$result != 0 || $output == ""} { + fail $command + } else { + pass $command + } + + # gdb testsuite will put there also needless -lm. + set test "$command output contains libc" + set libc [regexp -all -inline -line {^.* => (/[^ ]+).*$} $output] + if {[llength $libc] == 0} { + fail $test + } else { + pass $test + } + + set dests {} + for {set i 1} {$i < [llength $libc]} {incr i 2} { + set abspath [lindex $libc $i] + set dest "$dir/[file tail $abspath]" + copy $abspath $dest + lappend dests $dest + } + + if {[prelink$binprelink "--dynamic-linker=$interp --ld-library-path=$dir $exec $interp [concat $dests]" $exec] + && [copy $interp_saved $interp]} { + test_ld $exec 1 + } + } + } + } + + file delete $interp_saved + } +} +set pf_prefix $old_ldprefix |