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This commits the result of running gdb/copyright.py as per our Start
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gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
223 lines
7.3 KiB
C
223 lines
7.3 KiB
C
/* Reading symbol files from memory.
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Copyright (C) 1986-2021 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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/* This file defines functions (and commands to exercise those
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functions) for reading debugging information from object files
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whose images are mapped directly into the inferior's memory. For
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example, the Linux kernel maps a "syscall DSO" into each process's
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address space; this DSO provides kernel-specific code for some
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system calls.
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At the moment, BFD only has functions for parsing object files from
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memory for the ELF format, even though the general idea isn't
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ELF-specific. This means that BFD only provides the functions GDB
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needs when configured for ELF-based targets. So these functions
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may only be compiled on ELF-based targets.
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GDB has no idea whether it has been configured for an ELF-based
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target or not: it just tries to handle whatever files it is given.
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But this means there are no preprocessor symbols on which we could
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make these functions' compilation conditional.
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So, for the time being, we put these functions alone in this file,
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and have .mt files reference them as appropriate. In the future, I
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hope BFD will provide a format-independent bfd_from_remote_memory
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entry point. */
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#include "defs.h"
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#include "symtab.h"
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#include "gdbcore.h"
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#include "objfiles.h"
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#include "gdbcmd.h"
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#include "target.h"
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#include "value.h"
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#include "symfile.h"
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#include "observable.h"
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#include "auxv.h"
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#include "elf/common.h"
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#include "gdb_bfd.h"
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#include "inferior.h"
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/* Verify parameters of target_read_memory_bfd and target_read_memory are
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compatible. */
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gdb_static_assert (sizeof (CORE_ADDR) >= sizeof (bfd_vma));
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gdb_static_assert (sizeof (gdb_byte) == sizeof (bfd_byte));
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gdb_static_assert (sizeof (ssize_t) <= sizeof (bfd_size_type));
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/* Provide bfd/ compatible prototype for target_read_memory. Casting would not
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be enough as LEN width may differ. */
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static int
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target_read_memory_bfd (bfd_vma memaddr, bfd_byte *myaddr, bfd_size_type len)
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{
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/* MYADDR must be already allocated for the LEN size so it has to fit in
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ssize_t. */
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gdb_assert ((ssize_t) len == len);
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return target_read_memory (memaddr, myaddr, len);
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}
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/* Read inferior memory at ADDR to find the header of a loaded object file
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and read its in-core symbols out of inferior memory. SIZE, if
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non-zero, is the known size of the object. TEMPL is a bfd
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representing the target's format. NAME is the name to use for this
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symbol file in messages; it can be NULL. */
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static struct objfile *
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symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr,
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size_t size, const char *name, int from_tty)
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{
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struct objfile *objf;
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struct bfd *nbfd;
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struct bfd_section *sec;
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bfd_vma loadbase;
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symfile_add_flags add_flags = 0;
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if (bfd_get_flavour (templ) != bfd_target_elf_flavour)
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error (_("add-symbol-file-from-memory not supported for this target"));
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nbfd = bfd_elf_bfd_from_remote_memory (templ, addr, size, &loadbase,
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target_read_memory_bfd);
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if (nbfd == NULL)
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error (_("Failed to read a valid object file image from memory."));
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/* Manage the new reference for the duration of this function. */
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gdb_bfd_ref_ptr nbfd_holder = gdb_bfd_ref_ptr::new_reference (nbfd);
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if (name == NULL)
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name = "shared object read from target memory";
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bfd_set_filename (nbfd, name);
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if (!bfd_check_format (nbfd, bfd_object))
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error (_("Got object file from memory but can't read symbols: %s."),
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bfd_errmsg (bfd_get_error ()));
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section_addr_info sai;
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for (sec = nbfd->sections; sec != NULL; sec = sec->next)
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if ((bfd_section_flags (sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
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sai.emplace_back (bfd_section_vma (sec) + loadbase,
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bfd_section_name (sec),
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sec->index);
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if (from_tty)
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add_flags |= SYMFILE_VERBOSE;
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objf = symbol_file_add_from_bfd (nbfd, bfd_get_filename (nbfd),
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add_flags, &sai, OBJF_SHARED, NULL);
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current_program_space->add_target_sections (objf);
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/* This might change our ideas about frames already looked at. */
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reinit_frame_cache ();
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return objf;
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}
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static void
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add_symbol_file_from_memory_command (const char *args, int from_tty)
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{
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CORE_ADDR addr;
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struct bfd *templ;
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if (args == NULL)
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error (_("add-symbol-file-from-memory requires an expression argument"));
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addr = parse_and_eval_address (args);
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/* We need some representative bfd to know the target we are looking at. */
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if (current_program_space->symfile_object_file != NULL)
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templ = current_program_space->symfile_object_file->obfd;
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else
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templ = current_program_space->exec_bfd ();
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if (templ == NULL)
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error (_("Must use symbol-file or exec-file "
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"before add-symbol-file-from-memory."));
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symbol_file_add_from_memory (templ, addr, 0, NULL, from_tty);
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}
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/* Try to add the symbols for the vsyscall page, if there is one.
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This function is called via the inferior_created observer. */
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static void
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add_vsyscall_page (inferior *inf)
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{
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struct mem_range vsyscall_range;
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if (gdbarch_vsyscall_range (inf->gdbarch, &vsyscall_range))
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{
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struct bfd *bfd;
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if (core_bfd != NULL)
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bfd = core_bfd;
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else if (current_program_space->exec_bfd () != NULL)
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bfd = current_program_space->exec_bfd ();
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else
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/* FIXME: cagney/2004-05-06: Should not require an existing
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BFD when trying to create a run-time BFD of the VSYSCALL
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page in the inferior. Unfortunately that's the current
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interface so for the moment bail. Introducing a
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``bfd_runtime'' (a BFD created using the loaded image) file
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format should fix this. */
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{
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warning (_("Could not load vsyscall page "
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"because no executable was specified"));
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return;
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}
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std::string name = string_printf ("system-supplied DSO at %s",
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paddress (target_gdbarch (),
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vsyscall_range.start));
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try
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{
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/* Pass zero for FROM_TTY, because the action of loading the
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vsyscall DSO was not triggered by the user, even if the
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user typed "run" at the TTY. */
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symbol_file_add_from_memory (bfd,
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vsyscall_range.start,
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vsyscall_range.length,
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name.c_str (),
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0 /* from_tty */);
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}
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catch (const gdb_exception &ex)
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{
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exception_print (gdb_stderr, ex);
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}
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}
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}
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void _initialize_symfile_mem ();
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void
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_initialize_symfile_mem ()
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{
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add_cmd ("add-symbol-file-from-memory", class_files,
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add_symbol_file_from_memory_command,
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_("Load the symbols out of memory from a "
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"dynamically loaded object file.\n"
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"Give an expression for the address "
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"of the file's shared object file header."),
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&cmdlist);
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/* Want to know of each new inferior so that its vsyscall info can
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be extracted. */
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gdb::observers::inferior_created.attach (add_vsyscall_page);
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}
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