From 416675305692976aca45860e24b963982a2e682a Mon Sep 17 00:00:00 2001 From: Mike Gulick Date: Mon, 30 Oct 2017 18:13:44 -0400 Subject: [PATCH] Fix gdb segv when objfile can't be opened This fixes PR 16577. This patch changes gdb_bfd_map_section to issue a warning rather than an error if it is unable to read the object file, and sets the size of the section/frame that it attempted to read to 0 on error. The description of gdb_bfd_map_section states that it will try to read or map the contents of the section SECT, and if successful, the section data is returned and *SIZE is set to the size of the section data. This function was throwing an error and leaving *SIZE as-is. Setting the section size to 0 indicates to dwarf2_build_frame_info that there is no data to read, otherwise it will try to read from an invalid frame pointer. Changing the error to a warning allows this to be handled gracefully. Additionally, the error was clobbering the breakpoint output indicating the current frame (function name, arguments, source file, and line number). E.g. Thread 3 "foo" hit Breakpoint 1, BFD: reopening /tmp/jna-1013829440/jna2973250704389291330.tmp: No such file or directory BFD: reopening /tmp/jna-1013829440/jna2973250704389291330.tmp: No such file or directory (gdb) While the "BFD: reopening ..." messages will still appear interspersed in the breakpoint output, the current frame info is now displayed: Thread 3 "foo" hit Breakpoint 1, BFD: reopening /tmp/jna-1013829440/jna1875755897659885075.tmp: No such file or directory BFD: reopening /tmp/jna-1013829440/jna1875755897659885075.tmp: No such file or directory warning: Can't read data for section '.eh_frame' in file '/tmp/jna-1013829440/jna1875755897659885075.tmp' do_something () at file.cpp:80 80 { (gdb) --- gdb/ChangeLog | 8 +++ gdb/gdb_bfd.c | 12 +++- gdb/gdb_bfd.h | 17 +++-- gdb/testsuite/ChangeLog | 8 +++ gdb/testsuite/gdb.base/solib-vanish-lib1.c | 24 +++++++ gdb/testsuite/gdb.base/solib-vanish-lib2.c | 22 ++++++ gdb/testsuite/gdb.base/solib-vanish-main.c | 75 ++++++++++++++++++++ gdb/testsuite/gdb.base/solib-vanish.exp | 107 +++++++++++++++++++++++++++++ 8 files changed, 261 insertions(+), 12 deletions(-) create mode 100644 gdb/testsuite/gdb.base/solib-vanish-lib1.c create mode 100644 gdb/testsuite/gdb.base/solib-vanish-lib2.c create mode 100644 gdb/testsuite/gdb.base/solib-vanish-main.c create mode 100644 gdb/testsuite/gdb.base/solib-vanish.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bfd3492..76e6548 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2017-10-30 Mike Gulick + + PR gdb/16577 + * gdb_bfd.c (gdb_bfd_map_section): If unable to read object file, issue + a warning instead of throwing an error, set section size to 0 and return + NULL. + * gdb_bfd.h (gdb_bfd_map_section): Update description. + 2018-01-17 Simon Marchi * nat/linux-ptrace.h (linux_ptrace_attach_fail_reason): Return diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c index 80ddd42..02b1375 100644 --- a/gdb/gdb_bfd.c +++ b/gdb/gdb_bfd.c @@ -702,9 +702,15 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type *size) data = NULL; if (!bfd_get_full_section_contents (abfd, sectp, &data)) - error (_("Can't read data for section '%s' in file '%s'"), - bfd_get_section_name (abfd, sectp), - bfd_get_filename (abfd)); + { + warning (_("Can't read data for section '%s' in file '%s'"), + bfd_get_section_name (abfd, sectp), + bfd_get_filename (abfd)); + /* Set size to 0 to prevent further attempts to read the invalid + section. */ + *size = 0; + return (const gdb_byte *) NULL; + } descriptor->data = data; done: diff --git a/gdb/gdb_bfd.h b/gdb/gdb_bfd.h index ea3fdeb..2e4ac2c 100644 --- a/gdb/gdb_bfd.h +++ b/gdb/gdb_bfd.h @@ -115,15 +115,14 @@ void gdb_bfd_mark_parent (bfd *child, bfd *parent); void gdb_bfd_record_inclusion (bfd *includer, bfd *includee); -/* Try to read or map the contents of the section SECT. If - successful, the section data is returned and *SIZE is set to the - size of the section data; this may not be the same as the size - according to bfd_get_section_size if the section was compressed. - The returned section data is associated with the BFD and will be - destroyed when the BFD is destroyed. There is no other way to free - it; for temporary uses of section data, see - bfd_malloc_and_get_section. SECT may not have relocations. This - function will throw on error. */ +/* Try to read or map the contents of the section SECT. If successful, the + section data is returned and *SIZE is set to the size of the section data; + this may not be the same as the size according to bfd_get_section_size if the + section was compressed. The returned section data is associated with the BFD + and will be destroyed when the BFD is destroyed. There is no other way to + free it; for temporary uses of section data, see bfd_malloc_and_get_section. + SECT may not have relocations. If there is an error reading the section, + this issues a warning, sets *SIZE to 0, and returns NULL. */ const gdb_byte *gdb_bfd_map_section (asection *section, bfd_size_type *size); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index cd99b84..2eaec1c 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2017-10-30 Mike Gulick + + PR gdb/16577 + * gdb.base/solib-vanish.exp: New. + * gdb.base/solib-vanish-main.c: New. + * gdb.base/solib-vanish-lib1.c: New. + * gdb.base/solib-vanish-lib2.c: New. + 2018-01-17 Yao Qi * gdb.compile/compile.exp: Match the address printed for diff --git a/gdb/testsuite/gdb.base/solib-vanish-lib1.c b/gdb/testsuite/gdb.base/solib-vanish-lib1.c new file mode 100644 index 0000000..68c78ec --- /dev/null +++ b/gdb/testsuite/gdb.base/solib-vanish-lib1.c @@ -0,0 +1,24 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2017-2018 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 . */ + +extern int bar (int); + +int +foo (int x) +{ + return bar (x); +} diff --git a/gdb/testsuite/gdb.base/solib-vanish-lib2.c b/gdb/testsuite/gdb.base/solib-vanish-lib2.c new file mode 100644 index 0000000..78fb4e2 --- /dev/null +++ b/gdb/testsuite/gdb.base/solib-vanish-lib2.c @@ -0,0 +1,22 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2017-2018 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 . */ + +int +bar (int y) +{ + return y + 1; /* break here */ +} diff --git a/gdb/testsuite/gdb.base/solib-vanish-main.c b/gdb/testsuite/gdb.base/solib-vanish-main.c new file mode 100644 index 0000000..a00ee17 --- /dev/null +++ b/gdb/testsuite/gdb.base/solib-vanish-main.c @@ -0,0 +1,75 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2017-2018 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 . */ + +#include +#include +#include +#include +#include + +int +main () +{ + void *handle; + int (*foo) (int); + char *error; + char *dest = VANISH_LIB ".renamed"; + + /* Open library. */ + handle = dlopen (VANISH_LIB, RTLD_NOW); + if (!handle) + { + fprintf (stderr, "%s\n", dlerror ()); + exit (EXIT_FAILURE); + } + + /* Clear any existing error */ + dlerror (); + + /* Simulate deleting file by renaming it. */ + if (rename (VANISH_LIB, dest) == -1) + { + error = strerror (errno); + fprintf (stderr, "rename %s -> %s: %s\n", VANISH_LIB, dest, error); + exit (EXIT_FAILURE); + } + + /* Get function pointer. */ + foo = dlsym (handle, "foo"); + error = dlerror (); + if (error != NULL) + { + fprintf (stderr, "%s\n", error); + exit (EXIT_FAILURE); + } + + /* Call function. */ + (*foo) (1); + + /* Close and exit. */ + dlclose (handle); + + /* Put VANISH_LIB back where we found it. */ + if (rename (dest, VANISH_LIB) == -1) + { + error = strerror (errno); + fprintf (stderr, "rename %s -> %s: %s\n", dest, VANISH_LIB, error); + exit (EXIT_FAILURE); + } + + exit (EXIT_SUCCESS); +} diff --git a/gdb/testsuite/gdb.base/solib-vanish.exp b/gdb/testsuite/gdb.base/solib-vanish.exp new file mode 100644 index 0000000..928ca4e --- /dev/null +++ b/gdb/testsuite/gdb.base/solib-vanish.exp @@ -0,0 +1,107 @@ +# Copyright 2017-2018 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 . +# + +# This test case verifies that GDB gracefully handles a shared library file +# vanishing after being dlopen'ed. This consists of three nested function calls: +# +# main() -> foo() -> bar() +# +# where: +# - foo exists in solib-vanish-lib1.so, which is dlopen'ed by main() +# - bar exists in solib-vanish-lib2.so, which is dynamically linked into +# solib-vanish-lib1.so +# +# Immediately after dlopen'ing solib-vanish-lib1.so, the so file is moved aside +# by renaming. The main executable and solib-vanish-lib2.so are still +# accessible. +# +# If a breakpoint is set on bar(), gdb throws an error when this breakpoint is +# hit: +# +# (gdb) r +# Starting program: /local/gdb/git/pr_16577_repro/simple/solib-vanish-main +# +# Breakpoint 1, BFD: reopening ./solib-vanish-lib1.so: No such file or directory +# +# BFD: reopening ./solib-vanish-lib1.so: No such file or directory +# +# (gdb) +# +# Notice that this does not print the current frame, i.e.: +# bar (y=1) at solib-vanish-lib2.c:19 +# 19 return y + 1; /* break here */ +# (gdb) +# +# The current gdb git tip segfaults if we then try to step: +# (gdb) n +# Segmentation fault + +# This test verifies that: +# 1) GDB does not segfault when stepping +# 2) The stack frame is printed + +if { [skip_shlib_tests] } { + return 0 +} + +# Library 2 +set lib2name "solib-vanish-lib2" +set srcfile_lib2 ${srcdir}/${subdir}/${lib2name}.c +set binfile_lib2 [standard_output_file ${lib2name}.so] +set lib2_flags {debug} + +# Library 1 +set lib1name "solib-vanish-lib1" +set srcfile_lib1 ${srcdir}/${subdir}/${lib1name}.c +set binfile_lib1 [standard_output_file ${lib1name}.so] +set lib1_flags [list debug shlib=${binfile_lib2}] + +# Main program +set testfile "solib-vanish-main" +set srcfile ${srcdir}/${subdir}/${testfile}.c +set executable ${testfile} +set binfile [standard_output_file ${executable}] +set bin_flags [list debug shlib_load additional_flags=-DVANISH_LIB=\"${binfile_lib1}\"] + +if { [gdb_compile_shlib ${srcfile_lib2} ${binfile_lib2} $lib2_flags] != "" + || [gdb_compile_shlib ${srcfile_lib1} ${binfile_lib1} $lib1_flags] != "" + || [gdb_compile ${srcfile} ${binfile} executable $bin_flags] != "" } { + untested "failed to compile" + return -1 +} + +clean_restart $testfile + +if { ![runto_main] } { + fail "can't run to main" + return +} + +delete_breakpoints + +set lib2_lineno [gdb_get_line_number "break here" ${srcfile_lib2}] + +gdb_breakpoint "${lib2name}.c:${lib2_lineno}" {allow-pending} + +# Verify that both the location and source code are displayed +gdb_continue_to_breakpoint "bar" \ + ".*/${lib2name}.c:${lib2_lineno}.*break here.*" + +# This should not segfault +gdb_test "next" \ + "" \ + "next succeeds" + -- 2.7.4