a7b1986e13
This replaces a TRY/CATCH in write_gcore_file with a use of SCOPE_EXIT instead. I find that this is simpler to understand. 2019-03-06 Tom Tromey <tom@tromey.com> * gcore.c (write_gcore_file): Use SCOPE_EXIT.
605 lines
17 KiB
C
605 lines
17 KiB
C
/* Generate a core file for the inferior process.
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Copyright (C) 2001-2019 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "elf-bfd.h"
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#include "infcall.h"
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#include "inferior.h"
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#include "gdbcore.h"
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#include "objfiles.h"
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#include "solib.h"
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#include "symfile.h"
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#include "arch-utils.h"
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#include "completer.h"
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#include "gcore.h"
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#include "cli/cli-decode.h"
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#include <fcntl.h>
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#include "regcache.h"
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#include "regset.h"
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#include "gdb_bfd.h"
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#include "readline/tilde.h"
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#include <algorithm>
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#include "common/gdb_unlinker.h"
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#include "common/byte-vector.h"
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#include "common/scope-exit.h"
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/* The largest amount of memory to read from the target at once. We
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must throttle it to limit the amount of memory used by GDB during
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generate-core-file for programs with large resident data. */
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#define MAX_COPY_BYTES (1024 * 1024)
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static const char *default_gcore_target (void);
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static enum bfd_architecture default_gcore_arch (void);
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static unsigned long default_gcore_mach (void);
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static int gcore_memory_sections (bfd *);
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/* create_gcore_bfd -- helper for gcore_command (exported).
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Open a new bfd core file for output, and return the handle. */
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gdb_bfd_ref_ptr
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create_gcore_bfd (const char *filename)
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{
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gdb_bfd_ref_ptr obfd (gdb_bfd_openw (filename, default_gcore_target ()));
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if (obfd == NULL)
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error (_("Failed to open '%s' for output."), filename);
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bfd_set_format (obfd.get (), bfd_core);
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bfd_set_arch_mach (obfd.get (), default_gcore_arch (), default_gcore_mach ());
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return obfd;
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}
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/* write_gcore_file_1 -- do the actual work of write_gcore_file. */
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static void
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write_gcore_file_1 (bfd *obfd)
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{
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gdb::unique_xmalloc_ptr<char> note_data;
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int note_size = 0;
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asection *note_sec = NULL;
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/* An external target method must build the notes section. */
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/* FIXME: uweigand/2011-10-06: All architectures that support core file
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generation should be converted to gdbarch_make_corefile_notes; at that
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point, the target vector method can be removed. */
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if (!gdbarch_make_corefile_notes_p (target_gdbarch ()))
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note_data.reset (target_make_corefile_notes (obfd, ¬e_size));
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else
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note_data.reset (gdbarch_make_corefile_notes (target_gdbarch (), obfd,
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¬e_size));
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if (note_data == NULL || note_size == 0)
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error (_("Target does not support core file generation."));
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/* Create the note section. */
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note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
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SEC_HAS_CONTENTS
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| SEC_READONLY
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| SEC_ALLOC);
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if (note_sec == NULL)
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error (_("Failed to create 'note' section for corefile: %s"),
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bfd_errmsg (bfd_get_error ()));
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bfd_set_section_vma (obfd, note_sec, 0);
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bfd_set_section_alignment (obfd, note_sec, 0);
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bfd_set_section_size (obfd, note_sec, note_size);
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/* Now create the memory/load sections. */
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if (gcore_memory_sections (obfd) == 0)
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error (_("gcore: failed to get corefile memory sections from target."));
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/* Write out the contents of the note section. */
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if (!bfd_set_section_contents (obfd, note_sec, note_data.get (), 0,
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note_size))
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warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
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}
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/* write_gcore_file -- helper for gcore_command (exported).
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Compose and write the corefile data to the core file. */
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void
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write_gcore_file (bfd *obfd)
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{
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target_prepare_to_generate_core ();
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SCOPE_EXIT { target_done_generating_core (); };
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write_gcore_file_1 (obfd);
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}
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/* gcore_command -- implements the 'gcore' command.
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Generate a core file from the inferior process. */
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static void
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gcore_command (const char *args, int from_tty)
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{
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gdb::unique_xmalloc_ptr<char> corefilename;
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/* No use generating a corefile without a target process. */
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if (!target_has_execution)
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noprocess ();
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if (args && *args)
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corefilename.reset (tilde_expand (args));
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else
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{
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/* Default corefile name is "core.PID". */
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corefilename.reset (xstrprintf ("core.%d", inferior_ptid.pid ()));
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}
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if (info_verbose)
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fprintf_filtered (gdb_stdout,
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"Opening corefile '%s' for output.\n",
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corefilename.get ());
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/* Open the output file. */
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gdb_bfd_ref_ptr obfd (create_gcore_bfd (corefilename.get ()));
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/* Arrange to unlink the file on failure. */
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gdb::unlinker unlink_file (corefilename.get ());
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/* Call worker function. */
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write_gcore_file (obfd.get ());
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/* Succeeded. */
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unlink_file.keep ();
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fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename.get ());
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}
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static unsigned long
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default_gcore_mach (void)
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{
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#if 1 /* See if this even matters... */
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return 0;
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#else
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const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
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if (bfdarch != NULL)
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return bfdarch->mach;
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if (exec_bfd == NULL)
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error (_("Can't find default bfd machine type (need execfile)."));
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return bfd_get_mach (exec_bfd);
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#endif /* 1 */
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}
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static enum bfd_architecture
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default_gcore_arch (void)
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{
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const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
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if (bfdarch != NULL)
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return bfdarch->arch;
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if (exec_bfd == NULL)
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error (_("Can't find bfd architecture for corefile (need execfile)."));
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return bfd_get_arch (exec_bfd);
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}
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static const char *
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default_gcore_target (void)
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{
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/* The gdbarch may define a target to use for core files. */
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if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
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return gdbarch_gcore_bfd_target (target_gdbarch ());
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/* Otherwise, try to fall back to the exec_bfd target. This will probably
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not work for non-ELF targets. */
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if (exec_bfd == NULL)
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return NULL;
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else
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return bfd_get_target (exec_bfd);
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}
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/* Derive a reasonable stack segment by unwinding the target stack,
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and store its limits in *BOTTOM and *TOP. Return non-zero if
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successful. */
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static int
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derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
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{
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struct frame_info *fi, *tmp_fi;
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gdb_assert (bottom);
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gdb_assert (top);
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/* Can't succeed without stack and registers. */
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if (!target_has_stack || !target_has_registers)
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return 0;
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/* Can't succeed without current frame. */
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fi = get_current_frame ();
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if (fi == NULL)
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return 0;
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/* Save frame pointer of TOS frame. */
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*top = get_frame_base (fi);
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/* If current stack pointer is more "inner", use that instead. */
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if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
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*top = get_frame_sp (fi);
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/* Find prev-most frame. */
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while ((tmp_fi = get_prev_frame (fi)) != NULL)
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fi = tmp_fi;
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/* Save frame pointer of prev-most frame. */
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*bottom = get_frame_base (fi);
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/* Now canonicalize their order, so that BOTTOM is a lower address
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(as opposed to a lower stack frame). */
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if (*bottom > *top)
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{
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bfd_vma tmp_vma;
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tmp_vma = *top;
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*top = *bottom;
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*bottom = tmp_vma;
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}
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return 1;
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}
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/* call_target_sbrk --
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helper function for derive_heap_segment. */
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static bfd_vma
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call_target_sbrk (int sbrk_arg)
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{
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struct objfile *sbrk_objf;
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struct gdbarch *gdbarch;
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bfd_vma top_of_heap;
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struct value *target_sbrk_arg;
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struct value *sbrk_fn, *ret;
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bfd_vma tmp;
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if (lookup_minimal_symbol ("sbrk", NULL, NULL).minsym != NULL)
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{
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sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
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if (sbrk_fn == NULL)
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return (bfd_vma) 0;
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}
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else if (lookup_minimal_symbol ("_sbrk", NULL, NULL).minsym != NULL)
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{
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sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
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if (sbrk_fn == NULL)
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return (bfd_vma) 0;
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}
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else
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return (bfd_vma) 0;
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gdbarch = get_objfile_arch (sbrk_objf);
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target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
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sbrk_arg);
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gdb_assert (target_sbrk_arg);
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ret = call_function_by_hand (sbrk_fn, NULL, target_sbrk_arg);
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if (ret == NULL)
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return (bfd_vma) 0;
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tmp = value_as_long (ret);
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if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
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return (bfd_vma) 0;
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top_of_heap = tmp;
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return top_of_heap;
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}
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/* Derive a reasonable heap segment for ABFD by looking at sbrk and
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the static data sections. Store its limits in *BOTTOM and *TOP.
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Return non-zero if successful. */
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static int
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derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
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{
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bfd_vma top_of_data_memory = 0;
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bfd_vma top_of_heap = 0;
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bfd_size_type sec_size;
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bfd_vma sec_vaddr;
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asection *sec;
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gdb_assert (bottom);
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gdb_assert (top);
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/* This function depends on being able to call a function in the
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inferior. */
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if (!target_has_execution)
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return 0;
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/* The following code assumes that the link map is arranged as
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follows (low to high addresses):
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---------------------------------
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| text sections |
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---------------------------------
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| data sections (including bss) |
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---------------------------------
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| heap |
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--------------------------------- */
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for (sec = abfd->sections; sec; sec = sec->next)
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{
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if (bfd_get_section_flags (abfd, sec) & SEC_DATA
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|| strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
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{
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sec_vaddr = bfd_get_section_vma (abfd, sec);
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sec_size = bfd_get_section_size (sec);
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if (sec_vaddr + sec_size > top_of_data_memory)
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top_of_data_memory = sec_vaddr + sec_size;
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}
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}
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top_of_heap = call_target_sbrk (0);
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if (top_of_heap == (bfd_vma) 0)
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return 0;
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/* Return results. */
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if (top_of_heap > top_of_data_memory)
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{
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*bottom = top_of_data_memory;
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*top = top_of_heap;
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return 1;
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}
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/* No additional heap space needs to be saved. */
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return 0;
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}
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static void
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make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
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{
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int p_flags = 0;
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int p_type = 0;
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/* FIXME: these constants may only be applicable for ELF. */
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if (startswith (bfd_section_name (obfd, osec), "load"))
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p_type = PT_LOAD;
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else if (startswith (bfd_section_name (obfd, osec), "note"))
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p_type = PT_NOTE;
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else
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p_type = PT_NULL;
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p_flags |= PF_R; /* Segment is readable. */
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if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
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p_flags |= PF_W; /* Segment is writable. */
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if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
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p_flags |= PF_X; /* Segment is executable. */
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bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
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}
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/* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
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GDB is creating. */
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static int
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gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
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int write, int exec, int modified, void *data)
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{
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bfd *obfd = (bfd *) data;
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asection *osec;
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flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
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/* If the memory segment has no permissions set, ignore it, otherwise
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when we later try to access it for read/write, we'll get an error
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or jam the kernel. */
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if (read == 0 && write == 0 && exec == 0 && modified == 0)
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{
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if (info_verbose)
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{
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fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
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plongest (size), paddress (target_gdbarch (), vaddr));
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}
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return 0;
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}
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if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
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{
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/* See if this region of memory lies inside a known file on disk.
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If so, we can avoid copying its contents by clearing SEC_LOAD. */
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struct obj_section *objsec;
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for (objfile *objfile : current_program_space->objfiles ())
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ALL_OBJFILE_OSECTIONS (objfile, objsec)
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{
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bfd *abfd = objfile->obfd;
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asection *asec = objsec->the_bfd_section;
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bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
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asec);
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bfd_vma start = obj_section_addr (objsec) & -align;
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bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
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/* Match if either the entire memory region lies inside the
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section (i.e. a mapping covering some pages of a large
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segment) or the entire section lies inside the memory region
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(i.e. a mapping covering multiple small sections).
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This BFD was synthesized from reading target memory,
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we don't want to omit that. */
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if (objfile->separate_debug_objfile_backlink == NULL
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&& ((vaddr >= start && vaddr + size <= end)
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|| (start >= vaddr && end <= vaddr + size))
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&& !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
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{
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flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
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goto keep; /* Break out of two nested for loops. */
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}
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}
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keep:;
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}
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if (write == 0)
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flags |= SEC_READONLY;
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if (exec)
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flags |= SEC_CODE;
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else
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flags |= SEC_DATA;
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osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
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if (osec == NULL)
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{
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warning (_("Couldn't make gcore segment: %s"),
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bfd_errmsg (bfd_get_error ()));
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return 1;
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}
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if (info_verbose)
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{
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fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
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plongest (size), paddress (target_gdbarch (), vaddr));
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}
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bfd_set_section_size (obfd, osec, size);
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bfd_set_section_vma (obfd, osec, vaddr);
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bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
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return 0;
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}
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int
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objfile_find_memory_regions (struct target_ops *self,
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find_memory_region_ftype func, void *obfd)
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{
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/* Use objfile data to create memory sections. */
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struct obj_section *objsec;
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bfd_vma temp_bottom, temp_top;
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/* Call callback function for each objfile section. */
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for (objfile *objfile : current_program_space->objfiles ())
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ALL_OBJFILE_OSECTIONS (objfile, objsec)
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{
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bfd *ibfd = objfile->obfd;
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asection *isec = objsec->the_bfd_section;
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flagword flags = bfd_get_section_flags (ibfd, isec);
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/* Separate debug info files are irrelevant for gcore. */
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if (objfile->separate_debug_objfile_backlink != NULL)
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continue;
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if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
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{
|
|
int size = bfd_section_size (ibfd, isec);
|
|
int ret;
|
|
|
|
ret = (*func) (obj_section_addr (objsec), size,
|
|
1, /* All sections will be readable. */
|
|
(flags & SEC_READONLY) == 0, /* Writable. */
|
|
(flags & SEC_CODE) != 0, /* Executable. */
|
|
1, /* MODIFIED is unknown, pass it as true. */
|
|
obfd);
|
|
if (ret != 0)
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
/* Make a stack segment. */
|
|
if (derive_stack_segment (&temp_bottom, &temp_top))
|
|
(*func) (temp_bottom, temp_top - temp_bottom,
|
|
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. */
|
|
if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
|
|
(*func) (temp_bottom, temp_top - temp_bottom,
|
|
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;
|
|
}
|
|
|
|
static void
|
|
gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
|
|
{
|
|
bfd_size_type size, total_size = bfd_section_size (obfd, osec);
|
|
file_ptr offset = 0;
|
|
|
|
/* Read-only sections are marked; we don't have to copy their contents. */
|
|
if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
|
|
return;
|
|
|
|
/* Only interested in "load" sections. */
|
|
if (!startswith (bfd_section_name (obfd, osec), "load"))
|
|
return;
|
|
|
|
size = std::min (total_size, (bfd_size_type) MAX_COPY_BYTES);
|
|
gdb::byte_vector memhunk (size);
|
|
|
|
while (total_size > 0)
|
|
{
|
|
if (size > total_size)
|
|
size = total_size;
|
|
|
|
if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
|
|
memhunk.data (), size) != 0)
|
|
{
|
|
warning (_("Memory read failed for corefile "
|
|
"section, %s bytes at %s."),
|
|
plongest (size),
|
|
paddress (target_gdbarch (), bfd_section_vma (obfd, osec)));
|
|
break;
|
|
}
|
|
if (!bfd_set_section_contents (obfd, osec, memhunk.data (),
|
|
offset, size))
|
|
{
|
|
warning (_("Failed to write corefile contents (%s)."),
|
|
bfd_errmsg (bfd_get_error ()));
|
|
break;
|
|
}
|
|
|
|
total_size -= size;
|
|
offset += size;
|
|
}
|
|
}
|
|
|
|
static int
|
|
gcore_memory_sections (bfd *obfd)
|
|
{
|
|
/* Try gdbarch method first, then fall back to target method. */
|
|
if (!gdbarch_find_memory_regions_p (target_gdbarch ())
|
|
|| gdbarch_find_memory_regions (target_gdbarch (),
|
|
gcore_create_callback, obfd) != 0)
|
|
{
|
|
if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
|
|
return 0; /* FIXME: error return/msg? */
|
|
}
|
|
|
|
/* Record phdrs for section-to-segment mapping. */
|
|
bfd_map_over_sections (obfd, make_output_phdrs, NULL);
|
|
|
|
/* Copy memory region contents. */
|
|
bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
|
|
|
|
return 1;
|
|
}
|
|
|
|
void
|
|
_initialize_gcore (void)
|
|
{
|
|
add_com ("generate-core-file", class_files, gcore_command, _("\
|
|
Save a core file with the current state of the debugged process.\n\
|
|
Usage: generate-core-file [FILENAME]\n\
|
|
Argument is optional filename. Default filename is 'core.PROCESS_ID'."));
|
|
|
|
add_com_alias ("gcore", "generate-core-file", class_files, 1);
|
|
}
|