From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21069 invoked by alias); 22 Sep 2010 21:33:00 -0000 Received: (qmail 21046 invoked by uid 22791); 22 Sep 2010 21:32:56 -0000 X-SWARE-Spam-Status: No, hits=-6.1 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_BJ,T_FRT_PROFILE2,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 22 Sep 2010 21:32:49 +0000 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o8MLWmlo006042 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 22 Sep 2010 17:32:48 -0400 Received: from host1.dyn.jankratochvil.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx08.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o8MLWjQC002390 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 22 Sep 2010 17:32:47 -0400 Received: from host1.dyn.jankratochvil.net (localhost [127.0.0.1]) by host1.dyn.jankratochvil.net (8.14.4/8.14.4) with ESMTP id o8MLWjnH025968 for ; Wed, 22 Sep 2010 23:32:45 +0200 Received: (from jkratoch@localhost) by host1.dyn.jankratochvil.net (8.14.4/8.14.4/Submit) id o8MLWj58025962 for gdb-patches@sourceware.org; Wed, 22 Sep 2010 23:32:45 +0200 Date: Thu, 23 Sep 2010 14:47:00 -0000 From: Jan Kratochvil To: gdb-patches@sourceware.org Subject: Re: [patch] Fix gcore writer for -Wl,-z,relro (PR corefiles/11804) Message-ID: <20100922213245.GA25769@host1.dyn.jankratochvil.net> References: <20100830091521.GB25961@host1.dyn.jankratochvil.net> <20100831172857.GB27390@host1.dyn.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100831172857.GB27390@host1.dyn.jankratochvil.net> User-Agent: Mutt/1.5.20 (2009-12-10) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-09/txt/msg00400.txt.bz2 Hi, a slight warning() improvement. There was a hint http://sourceware.org/bugzilla/show_bug.cgi?id=11804#c12 it may not always work right but that would be just a Linux kernel bug so that GDB part should be OK. Also it cannot be a regression, only more pages may be written out with this patch. Thanks, Jan On Tue, 31 Aug 2010 19:28:57 +0200, Jan Kratochvil wrote: > technical rediff due to the patch update: > > On Mon, 30 Aug 2010 11:15:21 +0200, Jan Kratochvil wrote: > Hi, > > currently for -Wl,-z,relro executables GDB will not dump the DYNAMIC segment > into the core file, failing to read shared library list later. > > (gdb) info sharedlibrary > >From To Syms Read Shared Object Library > 0x00007ffff7dddb20 0x00007ffff7df5c74 Yes /lib64/ld-linux-x86-64.so.2 > > This is just the fallback, GDB considers the executable uninitialized with > DT_DEBUG value zero. > > Linux kernel dumps it correctly, respecting if the page got ever modified > since being read from the disk, even if it is not (no longer) writable. > > No regressions on {x86_64,x86_64-m32,i686}-fedora14snapshot-linux-gnu. > > The "Shared_Dirty:" / "Private_Dirty:" / "Swap:" rule has been suggested by > Roland McGrath and confirmed by Larry Woodman. gdb/ 2010-09-22 Jan Kratochvil Fix gcore writer for -Wl,-z,relro. * defs.h (find_memory_region_ftype): New parameter `modified'. New comment. * fbsd-nat.c (fbsd_find_memory_regions): Pass -1 to func. * gcore.c (gcore_create_callback): New parameter `modified'. Consider segment as unmodified only if also MODIFIED is 0. Set SEC_READONLY just according to WRITE. (objfile_find_memory_regions): Pass new values for the `modified' parameter. * gnu-nat.c (gnu_find_memory_regions): Pass -1 for the `modified' parameter. * linux-nat.c (read_mapping): New parameters mapfilename and modified. (linux_nat_find_memory_regions): New variable `modified'. Try "/proc/%d/smaps" first. Pass `&modified' and `mapsfilename' to read_mapping. Call func with MODIFIED. (linux_nat_info_proc_cmd): Pass `fname1' and NULL to read_mapping. * procfs.c (find_memory_regions_callback): Pass -1 for the `modified' parameter. gdb/testsuite/ 2010-09-22 Jan Kratochvil Fix gcore writer for -Wl,-z,relro. * gdb.base/gcore-relro.exp: New file. * gdb.base/gcore-relro-main.c: New file. * gdb.base/gcore-relro-lib.c: New file. --- a/gdb/defs.h +++ b/gdb/defs.h @@ -638,9 +638,10 @@ extern void init_source_path (void); /* From exec.c */ +/* MODIFIED has value -1 for unknown, 0 for not modified, 1 for modified. */ typedef int (*find_memory_region_ftype) (CORE_ADDR addr, unsigned long size, int read, int write, int exec, - void *data); + int modified, void *data); /* Take over the 'find_mapped_memory' vector from exec.c. */ extern void exec_set_find_memory_regions --- a/gdb/fbsd-nat.c +++ b/gdb/fbsd-nat.c @@ -133,7 +133,7 @@ fbsd_find_memory_regions (find_memory_region_ftype func, void *obfd) } /* Invoke the callback function to create the corefile segment. */ - func (start, size, read, write, exec, obfd); + func (start, size, read, write, exec, -1, obfd); } do_cleanups (cleanup); --- a/gdb/gcore.c +++ b/gdb/gcore.c @@ -378,8 +378,8 @@ make_output_phdrs (bfd *obfd, asection *osec, void *ignored) } static int -gcore_create_callback (CORE_ADDR vaddr, unsigned long size, - int read, int write, int exec, void *data) +gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read, + int write, int exec, int modified, void *data) { bfd *obfd = data; asection *osec; @@ -388,7 +388,7 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size, /* If the memory segment has no permissions set, ignore it, otherwise when we later try to access it for read/write, we'll get an error or jam the kernel. */ - if (read == 0 && write == 0 && exec == 0) + if (read == 0 && write == 0 && exec == 0 && modified == 0) { if (info_verbose) { @@ -399,7 +399,7 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size, return 0; } - if (write == 0 && !solib_keep_data_in_core (vaddr, size)) + if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size)) { /* See if this region of memory lies inside a known file on disk. If so, we can avoid copying its contents by clearing SEC_LOAD. */ @@ -431,10 +431,12 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size, } } - keep: - flags |= SEC_READONLY; + keep:; } + if (write == 0) + flags |= SEC_READONLY; + if (exec) flags |= SEC_CODE; else @@ -484,6 +486,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd) 1, /* All sections will be readable. */ (flags & SEC_READONLY) == 0, /* Writable. */ (flags & SEC_CODE) != 0, /* Executable. */ + -1, /* Modified is unknown. */ obfd); if (ret != 0) return ret; @@ -496,6 +499,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd) 1, /* Stack section will be readable. */ 1, /* Stack section will be writable. */ 0, /* Stack section will not be executable. */ + 1, /* Stack section will be modified. */ obfd); /* Make a heap segment. */ @@ -504,6 +508,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd) 1, /* Heap section will be readable. */ 1, /* Heap section will be writable. */ 0, /* Heap section will not be executable. */ + 1, /* Heap section will be modified. */ obfd); return 0; --- a/gdb/gnu-nat.c +++ b/gdb/gnu-nat.c @@ -2544,7 +2544,7 @@ gnu_find_memory_regions (find_memory_region_ftype func, void *data) last_protection & VM_PROT_READ, last_protection & VM_PROT_WRITE, last_protection & VM_PROT_EXECUTE, - data); + -1, data); last_region_address = region_address; last_region_end = region_address += region_length; last_protection = protection; @@ -2557,7 +2557,7 @@ gnu_find_memory_regions (find_memory_region_ftype func, void *data) last_protection & VM_PROT_READ, last_protection & VM_PROT_WRITE, last_protection & VM_PROT_EXECUTE, - data); + -1, data); return 0; } --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -4078,12 +4078,9 @@ linux_child_pid_to_exec_file (int pid) /* Service function for corefiles and info proc. */ static int -read_mapping (FILE *mapfile, - long long *addr, - long long *endaddr, - char *permissions, - long long *offset, - char *device, long long *inode, char *filename) +read_mapping (FILE *mapfile, const char *mapfilename, long long *addr, + long long *endaddr, char *permissions, long long *offset, + char *device, long long *inode, char *filename, int *modified) { int ret = fscanf (mapfile, "%llx-%llx %s %llx %s %llx", addr, endaddr, permissions, offset, device, inode); @@ -4101,6 +4098,41 @@ read_mapping (FILE *mapfile, ret += fscanf (mapfile, "%[^\n]\n", filename); } + if (modified != NULL) + { + *modified = -1; + for (;;) + { + int ch, got; + char keyword[64 + 1]; + unsigned long number; + + ch = fgetc (mapfile); + if (ch != EOF) + ungetc (ch, mapfile); + if (ch < 'A' || ch > 'Z') + break; + got = fscanf (mapfile, "%64s%lu", keyword, &number); + do + ch = fgetc (mapfile); + while (ch != EOF && ch != '\n'); + if (got != 2) + { + warning (_("Error parsing file %s"), mapfilename); + break; + } + if (number != 0 && (strcmp (keyword, "Shared_Dirty:") == 0 + || strcmp (keyword, "Private_Dirty:") == 0 + || strcmp (keyword, "Swap:") == 0)) + *modified = 1; + else if (*modified == -1) + { + /* A valid line proves an smaps file is being read in. */ + *modified = 0; + } + } + } + return (ret != 0 && ret != EOF); } @@ -4115,13 +4147,17 @@ linux_nat_find_memory_regions (find_memory_region_ftype func, void *obfd) FILE *mapsfile; long long addr, endaddr, size, offset, inode; char permissions[8], device[8], filename[MAXPATHLEN]; - int read, write, exec; + int read, write, exec, modified; struct cleanup *cleanup; /* Compose the filename for the /proc memory map, and open it. */ - sprintf (mapsfilename, "/proc/%d/maps", pid); + sprintf (mapsfilename, "/proc/%d/smaps", pid); if ((mapsfile = fopen (mapsfilename, "r")) == NULL) - error (_("Could not open %s."), mapsfilename); + { + sprintf (mapsfilename, "/proc/%d/maps", pid); + if ((mapsfile = fopen (mapsfilename, "r")) == NULL) + error (_("Could not open %s."), mapsfilename); + } cleanup = make_cleanup_fclose (mapsfile); if (info_verbose) @@ -4129,8 +4165,9 @@ linux_nat_find_memory_regions (find_memory_region_ftype func, void *obfd) "Reading memory regions from %s\n", mapsfilename); /* Now iterate until end-of-file. */ - while (read_mapping (mapsfile, &addr, &endaddr, &permissions[0], - &offset, &device[0], &inode, &filename[0])) + while (read_mapping (mapsfile, mapsfilename, &addr, &endaddr, + &permissions[0], &offset, &device[0], &inode, + &filename[0], &modified)) { size = endaddr - addr; @@ -4153,7 +4190,7 @@ linux_nat_find_memory_regions (find_memory_region_ftype func, void *obfd) /* Invoke the callback function to create the corefile segment. */ - func (addr, size, read, write, exec, obfd); + func (addr, size, read, write, exec, modified, obfd); } do_cleanups (cleanup); return 0; @@ -4615,8 +4652,9 @@ linux_nat_info_proc_cmd (char *args, int from_tty) " Size", " Offset", "objfile"); } - while (read_mapping (procfile, &addr, &endaddr, &permissions[0], - &offset, &device[0], &inode, &filename[0])) + while (read_mapping (procfile, fname1, &addr, &endaddr, + &permissions[0], &offset, &device[0], &inode, + &filename[0], NULL)) { size = endaddr - addr; --- a/gdb/procfs.c +++ b/gdb/procfs.c @@ -5285,7 +5285,7 @@ find_memory_regions_callback (struct prmap *map, (map->pr_mflags & MA_READ) != 0, (map->pr_mflags & MA_WRITE) != 0, (map->pr_mflags & MA_EXEC) != 0, - data); + -1, data); } /* External interface. Calls a callback function once for each --- /dev/null +++ b/gdb/testsuite/gdb.base/gcore-relro-lib.c @@ -0,0 +1,21 @@ +/* Copyright 2010 Free Software Foundation, Inc. + + This file is part of GDB. + + 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 . */ + +void +lib (void) +{ +} --- /dev/null +++ b/gdb/testsuite/gdb.base/gcore-relro-main.c @@ -0,0 +1,25 @@ +/* Copyright 2010 Free Software Foundation, Inc. + + This file is part of GDB. + + 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 void lib (void); + +int +main (void) +{ + lib (); + return 0; +} --- /dev/null +++ b/gdb/testsuite/gdb.base/gcore-relro.exp @@ -0,0 +1,80 @@ +# 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 . + +if {[skip_shlib_tests]} { + return 0 +} + +set testfile "gcore-relro" +set srcmainfile ${testfile}-main.c +set srclibfile ${testfile}-lib.c +set libfile ${objdir}/${subdir}/${testfile}-lib.so +set objfile ${objdir}/${subdir}/${testfile}-main.o +set executable ${testfile}-main +set binfile ${objdir}/${subdir}/${executable} +set gcorefile ${objdir}/${subdir}/${executable}.gcore + +if { [gdb_compile_shlib ${srcdir}/${subdir}/${srclibfile} ${libfile} {debug}] != "" + || [gdb_compile ${srcdir}/${subdir}/${srcmainfile} ${objfile} object {debug}] != "" } { + untested ${testfile}.exp + return -1 +} +set opts [list debug shlib=${libfile} additional_flags=-Wl,-z,relro] +if { [gdb_compile ${objfile} ${binfile} executable $opts] != "" } { + unsupported "-Wl,-z,relro compilation failed" + return -1 +} + +clean_restart $executable +gdb_load_shlibs $libfile + +# Does this gdb support gcore? +set test "help gcore" +gdb_test_multiple $test $test { + -re "Undefined command: .gcore.*\r\n$gdb_prompt $" { + # gcore command not supported -- nothing to test here. + unsupported "gdb does not support gcore on this target" + return -1; + } + -re "Save a core file .*\r\n$gdb_prompt $" { + pass $test + } +} + +if { ![runto lib] } then { + return -1 +} + +set escapedfilename [string_to_regexp ${gcorefile}] + +set test "save a corefile" +gdb_test_multiple "gcore ${gcorefile}" $test { + -re "Saved corefile ${escapedfilename}\r\n$gdb_prompt $" { + pass $test + } + -re "Can't create a corefile\r\n$gdb_prompt $" { + unsupported $test + return -1 + } +} + +# Now restart gdb and load the corefile. + +clean_restart $executable +gdb_load_shlibs $libfile + +gdb_test "core ${gcorefile}" "Core was generated by .*" "re-load generated corefile" + +gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"