| 1 | /* Reading symbol files from memory. |
| 2 | |
| 3 | Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, |
| 4 | 2001, 2002, 2003, 2004 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | /* This file defines functions (and commands to exercise those |
| 24 | functions) for reading debugging information from object files |
| 25 | whose images are mapped directly into the inferior's memory. For |
| 26 | example, the Linux kernel maps a "syscall DSO" into each process's |
| 27 | address space; this DSO provides kernel-specific code for some |
| 28 | system calls. |
| 29 | |
| 30 | At the moment, BFD only has functions for parsing object files from |
| 31 | memory for the ELF format, even though the general idea isn't |
| 32 | ELF-specific. This means that BFD only provides the functions GDB |
| 33 | needs when configured for ELF-based targets. So these functions |
| 34 | may only be compiled on ELF-based targets. |
| 35 | |
| 36 | GDB has no idea whether it has been configured for an ELF-based |
| 37 | target or not: it just tries to handle whatever files it is given. |
| 38 | But this means there are no preprocessor symbols on which we could |
| 39 | make these functions' compilation conditional. |
| 40 | |
| 41 | So, for the time being, we put these functions alone in this file, |
| 42 | and have .mt files reference them as appropriate. In the future, I |
| 43 | hope BFD will provide a format-independent bfd_from_remote_memory |
| 44 | entry point. */ |
| 45 | |
| 46 | |
| 47 | #include "defs.h" |
| 48 | #include "symtab.h" |
| 49 | #include "gdbcore.h" |
| 50 | #include "objfiles.h" |
| 51 | #include "gdbcmd.h" |
| 52 | #include "target.h" |
| 53 | #include "value.h" |
| 54 | #include "symfile.h" |
| 55 | |
| 56 | |
| 57 | /* Read inferior memory at ADDR to find the header of a loaded object file |
| 58 | and read its in-core symbols out of inferior memory. TEMPL is a bfd |
| 59 | representing the target's format. */ |
| 60 | static struct objfile * |
| 61 | symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, int from_tty) |
| 62 | { |
| 63 | struct objfile *objf; |
| 64 | struct bfd *nbfd; |
| 65 | struct bfd_section *sec; |
| 66 | bfd_vma loadbase; |
| 67 | struct section_addr_info *sai; |
| 68 | unsigned int i; |
| 69 | |
| 70 | if (bfd_get_flavour (templ) != bfd_target_elf_flavour) |
| 71 | error ("add-symbol-file-from-memory not supported for this target"); |
| 72 | |
| 73 | nbfd = bfd_elf_bfd_from_remote_memory (templ, addr, &loadbase, |
| 74 | target_read_memory); |
| 75 | if (nbfd == NULL) |
| 76 | error ("Failed to read a valid object file image from memory."); |
| 77 | |
| 78 | nbfd->filename = xstrdup ("shared object read from target memory"); |
| 79 | |
| 80 | if (!bfd_check_format (nbfd, bfd_object)) |
| 81 | { |
| 82 | /* FIXME: should be checking for errors from bfd_close (for one thing, |
| 83 | on error it does not free all the storage associated with the |
| 84 | bfd). */ |
| 85 | bfd_close (nbfd); |
| 86 | error ("Got object file from memory but can't read symbols: %s.", |
| 87 | bfd_errmsg (bfd_get_error ())); |
| 88 | } |
| 89 | |
| 90 | sai = alloc_section_addr_info (bfd_count_sections (nbfd)); |
| 91 | make_cleanup (xfree, sai); |
| 92 | i = 0; |
| 93 | for (sec = nbfd->sections; sec != NULL; sec = sec->next) |
| 94 | if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0) |
| 95 | { |
| 96 | sai->other[i].addr = bfd_get_section_vma (nbfd, sec) + loadbase; |
| 97 | sai->other[i].name = (char *) bfd_get_section_name (nbfd, sec); |
| 98 | sai->other[i].sectindex = sec->index; |
| 99 | ++i; |
| 100 | } |
| 101 | |
| 102 | objf = symbol_file_add_from_bfd (nbfd, from_tty, |
| 103 | sai, 0, OBJF_SHARED); |
| 104 | |
| 105 | /* This might change our ideas about frames already looked at. */ |
| 106 | reinit_frame_cache (); |
| 107 | |
| 108 | return objf; |
| 109 | } |
| 110 | |
| 111 | |
| 112 | static void |
| 113 | add_symbol_file_from_memory_command (char *args, int from_tty) |
| 114 | { |
| 115 | CORE_ADDR addr; |
| 116 | struct bfd *templ; |
| 117 | |
| 118 | if (args == NULL) |
| 119 | error ("add-symbol-file-from-memory requires an expression argument"); |
| 120 | |
| 121 | addr = parse_and_eval_address (args); |
| 122 | |
| 123 | /* We need some representative bfd to know the target we are looking at. */ |
| 124 | if (symfile_objfile != NULL) |
| 125 | templ = symfile_objfile->obfd; |
| 126 | else |
| 127 | templ = exec_bfd; |
| 128 | if (templ == NULL) |
| 129 | error ("\ |
| 130 | Must use symbol-file or exec-file before add-symbol-file-from-memory."); |
| 131 | |
| 132 | symbol_file_add_from_memory (templ, addr, from_tty); |
| 133 | } |
| 134 | |
| 135 | \f |
| 136 | void |
| 137 | _initialize_symfile_mem (void) |
| 138 | { |
| 139 | add_cmd ("add-symbol-file-from-memory", class_files, |
| 140 | add_symbol_file_from_memory_command, |
| 141 | "\ |
| 142 | Load the symbols out of memory from a dynamically loaded object file.\n\ |
| 143 | Give an expression for the address of the file's shared object file header.", |
| 144 | &cmdlist); |
| 145 | |
| 146 | } |