/* Work with executable files, for GDB. Copyright (C) 1988-2014 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 . */ #include "defs.h" #include "frame.h" #include "inferior.h" #include "target.h" #include "gdbcmd.h" #include "language.h" #include "filenames.h" #include "symfile.h" #include "objfiles.h" #include "completer.h" #include "value.h" #include "exec.h" #include "observer.h" #include "arch-utils.h" #include "gdbthread.h" #include "progspace.h" #include "gdb_bfd.h" #include #include "readline/readline.h" #include #include "gdbcore.h" #include #include void (*deprecated_file_changed_hook) (char *); /* Prototypes for local functions */ static void file_command (char *, int); static void set_section_command (char *, int); static void exec_files_info (struct target_ops *); static void init_exec_ops (void); void _initialize_exec (void); /* The target vector for executable files. */ struct target_ops exec_ops; /* True if the exec target is pushed on the stack. */ static int using_exec_ops; /* Whether to open exec and core files read-only or read-write. */ int write_files = 0; static void show_write_files (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { fprintf_filtered (file, _("Writing into executable and core files is %s.\n"), value); } static void exec_open (char *args, int from_tty) { target_preopen (from_tty); exec_file_attach (args, from_tty); } /* Close and clear exec_bfd. If we end up with no target sections to read memory from, this unpushes the exec_ops target. */ void exec_close (void) { if (exec_bfd) { bfd *abfd = exec_bfd; gdb_bfd_unref (abfd); /* Removing target sections may close the exec_ops target. Clear exec_bfd before doing so to prevent recursion. */ exec_bfd = NULL; exec_bfd_mtime = 0; remove_target_sections (&exec_bfd); xfree (exec_filename); exec_filename = NULL; } } /* This is the target_close implementation. Clears all target sections and closes all executable bfds from all program spaces. */ static void exec_close_1 (void) { using_exec_ops = 0; { struct program_space *ss; struct cleanup *old_chain; old_chain = save_current_program_space (); ALL_PSPACES (ss) { set_current_program_space (ss); /* Delete all target sections. */ resize_section_table (current_target_sections, -resize_section_table (current_target_sections, 0)); exec_close (); } do_cleanups (old_chain); } } void exec_file_clear (int from_tty) { /* Remove exec file. */ exec_close (); if (from_tty) printf_unfiltered (_("No executable file now.\n")); } /* Set FILENAME as the new exec file. This function is intended to be behave essentially the same as exec_file_command, except that the latter will detect when a target is being debugged, and will ask the user whether it should be shut down first. (If the answer is "no", then the new file is ignored.) This file is used by exec_file_command, to do the work of opening and processing the exec file after any prompting has happened. And, it is used by child_attach, when the attach command was given a pid but not a exec pathname, and the attach command could figure out the pathname from the pid. (In this case, we shouldn't ask the user whether the current target should be shut down -- we're supplying the exec pathname late for good reason.) */ void exec_file_attach (char *filename, int from_tty) { /* Remove any previous exec file. */ exec_close (); /* Now open and digest the file the user requested, if any. */ if (!filename) { if (from_tty) printf_unfiltered (_("No executable file now.\n")); set_gdbarch_from_file (NULL); } else { struct cleanup *cleanups; char *scratch_pathname, *canonical_pathname; int scratch_chan; struct target_section *sections = NULL, *sections_end = NULL; char **matching; scratch_chan = openp (getenv ("PATH"), OPF_TRY_CWD_FIRST, filename, write_files ? O_RDWR | O_BINARY : O_RDONLY | O_BINARY, &scratch_pathname); #if defined(__GO32__) || defined(_WIN32) || defined(__CYGWIN__) if (scratch_chan < 0) { char *exename = alloca (strlen (filename) + 5); strcat (strcpy (exename, filename), ".exe"); scratch_chan = openp (getenv ("PATH"), OPF_TRY_CWD_FIRST, exename, write_files ? O_RDWR | O_BINARY : O_RDONLY | O_BINARY, &scratch_pathname); } #endif if (scratch_chan < 0) perror_with_name (filename); cleanups = make_cleanup (xfree, scratch_pathname); /* gdb_bfd_open (and its variants) prefers canonicalized pathname for better BFD caching. */ canonical_pathname = gdb_realpath (scratch_pathname); make_cleanup (xfree, canonical_pathname); if (write_files) exec_bfd = gdb_bfd_fopen (canonical_pathname, gnutarget, FOPEN_RUB, scratch_chan); else exec_bfd = gdb_bfd_open (canonical_pathname, gnutarget, scratch_chan); if (!exec_bfd) { error (_("\"%s\": could not open as an executable file: %s"), scratch_pathname, bfd_errmsg (bfd_get_error ())); } gdb_assert (exec_filename == NULL); exec_filename = gdb_realpath_keepfile (scratch_pathname); if (!bfd_check_format_matches (exec_bfd, bfd_object, &matching)) { /* Make sure to close exec_bfd, or else "run" might try to use it. */ exec_close (); error (_("\"%s\": not in executable format: %s"), scratch_pathname, gdb_bfd_errmsg (bfd_get_error (), matching)); } if (build_section_table (exec_bfd, §ions, §ions_end)) { /* Make sure to close exec_bfd, or else "run" might try to use it. */ exec_close (); error (_("\"%s\": can't find the file sections: %s"), scratch_pathname, bfd_errmsg (bfd_get_error ())); } exec_bfd_mtime = bfd_get_mtime (exec_bfd); validate_files (); set_gdbarch_from_file (exec_bfd); /* Add the executable's sections to the current address spaces' list of sections. This possibly pushes the exec_ops target. */ add_target_sections (&exec_bfd, sections, sections_end); xfree (sections); /* Tell display code (if any) about the changed file name. */ if (deprecated_exec_file_display_hook) (*deprecated_exec_file_display_hook) (filename); do_cleanups (cleanups); } bfd_cache_close_all (); observer_notify_executable_changed (); } /* Process the first arg in ARGS as the new exec file. Note that we have to explicitly ignore additional args, since we can be called from file_command(), which also calls symbol_file_command() which can take multiple args. If ARGS is NULL, we just want to close the exec file. */ static void exec_file_command (char *args, int from_tty) { char **argv; char *filename; if (from_tty && target_has_execution && !query (_("A program is being debugged already.\n" "Are you sure you want to change the file? "))) error (_("File not changed.")); if (args) { struct cleanup *cleanups; /* Scan through the args and pick up the first non option arg as the filename. */ argv = gdb_buildargv (args); cleanups = make_cleanup_freeargv (argv); for (; (*argv != NULL) && (**argv == '-'); argv++) {; } if (*argv == NULL) error (_("No executable file name was specified")); filename = tilde_expand (*argv); make_cleanup (xfree, filename); exec_file_attach (filename, from_tty); do_cleanups (cleanups); } else exec_file_attach (NULL, from_tty); } /* Set both the exec file and the symbol file, in one command. What a novelty. Why did GDB go through four major releases before this command was added? */ static void file_command (char *arg, int from_tty) { /* FIXME, if we lose on reading the symbol file, we should revert the exec file, but that's rough. */ exec_file_command (arg, from_tty); symbol_file_command (arg, from_tty); if (deprecated_file_changed_hook) deprecated_file_changed_hook (arg); } /* Locate all mappable sections of a BFD file. table_pp_char is a char * to get it through bfd_map_over_sections; we cast it back to its proper type. */ static void add_to_section_table (bfd *abfd, struct bfd_section *asect, void *table_pp_char) { struct target_section **table_pp = (struct target_section **) table_pp_char; flagword aflag; gdb_assert (abfd == asect->owner); /* Check the section flags, but do not discard zero-length sections, since some symbols may still be attached to this section. For instance, we encountered on sparc-solaris 2.10 a shared library with an empty .bss section to which a symbol named "_end" was attached. The address of this symbol still needs to be relocated. */ aflag = bfd_get_section_flags (abfd, asect); if (!(aflag & SEC_ALLOC)) return; (*table_pp)->owner = NULL; (*table_pp)->the_bfd_section = asect; (*table_pp)->addr = bfd_section_vma (abfd, asect); (*table_pp)->endaddr = (*table_pp)->addr + bfd_section_size (abfd, asect); (*table_pp)++; } int resize_section_table (struct target_section_table *table, int num_added) { int old_count; int new_count; old_count = table->sections_end - table->sections; new_count = num_added + old_count; if (new_count) { table->sections = xrealloc (table->sections, sizeof (struct target_section) * new_count); table->sections_end = table->sections + new_count; } else { xfree (table->sections); table->sections = table->sections_end = NULL; } return old_count; } /* Builds a section table, given args BFD, SECTABLE_PTR, SECEND_PTR. Returns 0 if OK, 1 on error. */ int build_section_table (struct bfd *some_bfd, struct target_section **start, struct target_section **end) { unsigned count; count = bfd_count_sections (some_bfd); if (*start) xfree (* start); *start = (struct target_section *) xmalloc (count * sizeof (**start)); *end = *start; bfd_map_over_sections (some_bfd, add_to_section_table, (char *) end); if (*end > *start + count) internal_error (__FILE__, __LINE__, _("failed internal consistency check")); /* We could realloc the table, but it probably loses for most files. */ return 0; } /* Add the sections array defined by [SECTIONS..SECTIONS_END[ to the current set of target sections. */ void add_target_sections (void *owner, struct target_section *sections, struct target_section *sections_end) { int count; struct target_section_table *table = current_target_sections; count = sections_end - sections; if (count > 0) { int space = resize_section_table (table, count); int i; for (i = 0; i < count; ++i) { table->sections[space + i] = sections[i]; table->sections[space + i].owner = owner; } /* If these are the first file sections we can provide memory from, push the file_stratum target. */ if (!using_exec_ops) { using_exec_ops = 1; push_target (&exec_ops); } } } /* Add the sections of OBJFILE to the current set of target sections. */ void add_target_sections_of_objfile (struct objfile *objfile) { struct target_section_table *table = current_target_sections; struct obj_section *osect; int space; unsigned count = 0; struct target_section *ts; if (objfile == NULL) return; /* Compute the number of sections to add. */ ALL_OBJFILE_OSECTIONS (objfile, osect) { if (bfd_get_section_size (osect->the_bfd_section) == 0) continue; count++; } if (count == 0) return; space = resize_section_table (table, count); ts = table->sections + space; ALL_OBJFILE_OSECTIONS (objfile, osect) { if (bfd_get_section_size (osect->the_bfd_section) == 0) continue; gdb_assert (ts < table->sections + space + count); ts->addr = obj_section_addr (osect); ts->endaddr = obj_section_endaddr (osect); ts->the_bfd_section = osect->the_bfd_section; ts->owner = (void *) objfile; ts++; } } /* Remove all target sections owned by OWNER. OWNER must be the same value passed to add_target_sections. */ void remove_target_sections (void *owner) { struct target_section *src, *dest; struct target_section_table *table = current_target_sections; gdb_assert (owner != NULL); dest = table->sections; for (src = table->sections; src < table->sections_end; src++) if (src->owner != owner) { /* Keep this section. */ if (dest < src) *dest = *src; dest++; } /* If we've dropped any sections, resize the section table. */ if (dest < src) { int old_count; old_count = resize_section_table (table, dest - src); /* If we don't have any more sections to read memory from, remove the file_stratum target from the stack. */ if (old_count + (dest - src) == 0) { struct program_space *pspace; ALL_PSPACES (pspace) if (pspace->target_sections.sections != pspace->target_sections.sections_end) return; unpush_target (&exec_ops); } } } VEC(mem_range_s) * section_table_available_memory (VEC(mem_range_s) *memory, CORE_ADDR memaddr, ULONGEST len, struct target_section *sections, struct target_section *sections_end) { struct target_section *p; for (p = sections; p < sections_end; p++) { if ((bfd_get_section_flags (p->the_bfd_section->owner, p->the_bfd_section) & SEC_READONLY) == 0) continue; /* Copy the meta-data, adjusted. */ if (mem_ranges_overlap (p->addr, p->endaddr - p->addr, memaddr, len)) { ULONGEST lo1, hi1, lo2, hi2; struct mem_range *r; lo1 = memaddr; hi1 = memaddr + len; lo2 = p->addr; hi2 = p->endaddr; r = VEC_safe_push (mem_range_s, memory, NULL); r->start = max (lo1, lo2); r->length = min (hi1, hi2) - r->start; } } return memory; } int section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, struct target_section *sections, struct target_section *sections_end, const char *section_name) { int res; struct target_section *p; ULONGEST memaddr = offset; ULONGEST memend = memaddr + len; if (len == 0) internal_error (__FILE__, __LINE__, _("failed internal consistency check")); for (p = sections; p < sections_end; p++) { struct bfd_section *asect = p->the_bfd_section; bfd *abfd = asect->owner; if (section_name && strcmp (section_name, asect->name) != 0) continue; /* not the section we need. */ if (memaddr >= p->addr) { if (memend <= p->endaddr) { /* Entire transfer is within this section. */ if (writebuf) res = bfd_set_section_contents (abfd, asect, writebuf, memaddr - p->addr, len); else res = bfd_get_section_contents (abfd, asect, readbuf, memaddr - p->addr, len); return (res != 0) ? len : 0; } else if (memaddr >= p->endaddr) { /* This section ends before the transfer starts. */ continue; } else { /* This section overlaps the transfer. Just do half. */ len = p->endaddr - memaddr; if (writebuf) res = bfd_set_section_contents (abfd, asect, writebuf, memaddr - p->addr, len); else res = bfd_get_section_contents (abfd, asect, readbuf, memaddr - p->addr, len); return (res != 0) ? len : 0; } } } return 0; /* We can't help. */ } static struct target_section_table * exec_get_section_table (struct target_ops *ops) { return current_target_sections; } static LONGEST exec_xfer_partial (struct target_ops *ops, enum target_object object, const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf, ULONGEST offset, ULONGEST len) { struct target_section_table *table = target_get_section_table (ops); if (object == TARGET_OBJECT_MEMORY) return section_table_xfer_memory_partial (readbuf, writebuf, offset, len, table->sections, table->sections_end, NULL); else return TARGET_XFER_E_IO; } void print_section_info (struct target_section_table *t, bfd *abfd) { struct gdbarch *gdbarch = gdbarch_from_bfd (abfd); struct target_section *p; /* FIXME: 16 is not wide enough when gdbarch_addr_bit > 64. */ int wid = gdbarch_addr_bit (gdbarch) <= 32 ? 8 : 16; printf_filtered ("\t`%s', ", bfd_get_filename (abfd)); wrap_here (" "); printf_filtered (_("file type %s.\n"), bfd_get_target (abfd)); if (abfd == exec_bfd) { /* gcc-3.4 does not like the initialization in

sections_end>. */ bfd_vma displacement = 0; bfd_vma entry_point; for (p = t->sections; p < t->sections_end; p++) { struct bfd_section *psect = p->the_bfd_section; bfd *pbfd = psect->owner; if ((bfd_get_section_flags (pbfd, psect) & (SEC_ALLOC | SEC_LOAD)) != (SEC_ALLOC | SEC_LOAD)) continue; if (bfd_get_section_vma (pbfd, psect) <= abfd->start_address && abfd->start_address < (bfd_get_section_vma (pbfd, psect) + bfd_get_section_size (psect))) { displacement = p->addr - bfd_get_section_vma (pbfd, psect); break; } } if (p == t->sections_end) warning (_("Cannot find section for the entry point of %s."), bfd_get_filename (abfd)); entry_point = gdbarch_addr_bits_remove (gdbarch, bfd_get_start_address (abfd) + displacement); printf_filtered (_("\tEntry point: %s\n"), paddress (gdbarch, entry_point)); } for (p = t->sections; p < t->sections_end; p++) { struct bfd_section *psect = p->the_bfd_section; bfd *pbfd = psect->owner; printf_filtered ("\t%s", hex_string_custom (p->addr, wid)); printf_filtered (" - %s", hex_string_custom (p->endaddr, wid)); /* FIXME: A format of "08l" is not wide enough for file offsets larger than 4GB. OTOH, making it "016l" isn't desirable either since most output will then be much wider than necessary. It may make sense to test the size of the file and choose the format string accordingly. */ /* FIXME: i18n: Need to rewrite this sentence. */ if (info_verbose) printf_filtered (" @ %s", hex_string_custom (psect->filepos, 8)); printf_filtered (" is %s", bfd_section_name (pbfd, psect)); if (pbfd != abfd) printf_filtered (" in %s", bfd_get_filename (pbfd)); printf_filtered ("\n"); } } static void exec_files_info (struct target_ops *t) { if (exec_bfd) print_section_info (current_target_sections, exec_bfd); else puts_filtered (_("\t\n")); } static void set_section_command (char *args, int from_tty) { struct target_section *p; char *secname; unsigned seclen; unsigned long secaddr; char secprint[100]; long offset; struct target_section_table *table; if (args == 0) error (_("Must specify section name and its virtual address")); /* Parse out section name. */ for (secname = args; !isspace (*args); args++); seclen = args - secname; /* Parse out new virtual address. */ secaddr = parse_and_eval_address (args); table = current_target_sections; for (p = table->sections; p < table->sections_end; p++) { if (!strncmp (secname, bfd_section_name (p->bfd, p->the_bfd_section), seclen) && bfd_section_name (p->bfd, p->the_bfd_section)[seclen] == '\0') { offset = secaddr - p->addr; p->addr += offset; p->endaddr += offset; if (from_tty) exec_files_info (&exec_ops); return; } } if (seclen >= sizeof (secprint)) seclen = sizeof (secprint) - 1; strncpy (secprint, secname, seclen); secprint[seclen] = '\0'; error (_("Section %s not found"), secprint); } /* If we can find a section in FILENAME with BFD index INDEX, adjust it to ADDRESS. */ void exec_set_section_address (const char *filename, int index, CORE_ADDR address) { struct target_section *p; struct target_section_table *table; table = current_target_sections; for (p = table->sections; p < table->sections_end; p++) { if (filename_cmp (filename, p->the_bfd_section->owner->filename) == 0 && index == p->the_bfd_section->index) { p->endaddr += address - p->addr; p->addr = address; } } } /* If mourn is being called in all the right places, this could be say `gdb internal error' (since generic_mourn calls breakpoint_init_inferior). */ static int ignore (struct target_ops *ops, struct gdbarch *gdbarch, struct bp_target_info *bp_tgt) { return 0; } static int exec_has_memory (struct target_ops *ops) { /* We can provide memory if we have any file/target sections to read from. */ return (current_target_sections->sections != current_target_sections->sections_end); } /* Find mapped memory. */ extern void exec_set_find_memory_regions (int (*func) (find_memory_region_ftype, void *)) { exec_ops.to_find_memory_regions = func; } static char *exec_make_note_section (bfd *, int *); /* Fill in the exec file target vector. Very few entries need to be defined. */ static void init_exec_ops (void) { exec_ops.to_shortname = "exec"; exec_ops.to_longname = "Local exec file"; exec_ops.to_doc = "Use an executable file as a target.\n\ Specify the filename of the executable file."; exec_ops.to_open = exec_open; exec_ops.to_close = exec_close_1; exec_ops.to_attach = find_default_attach; exec_ops.to_xfer_partial = exec_xfer_partial; exec_ops.to_get_section_table = exec_get_section_table; exec_ops.to_files_info = exec_files_info; exec_ops.to_insert_breakpoint = ignore; exec_ops.to_remove_breakpoint = ignore; exec_ops.to_create_inferior = find_default_create_inferior; exec_ops.to_stratum = file_stratum; exec_ops.to_has_memory = exec_has_memory; exec_ops.to_make_corefile_notes = exec_make_note_section; exec_ops.to_magic = OPS_MAGIC; } void _initialize_exec (void) { struct cmd_list_element *c; init_exec_ops (); if (!dbx_commands) { c = add_cmd ("file", class_files, file_command, _("\ Use FILE as program to be debugged.\n\ It is read for its symbols, for getting the contents of pure memory,\n\ and it is the program executed when you use the `run' command.\n\ If FILE cannot be found as specified, your execution directory path\n\ ($PATH) is searched for a command of that name.\n\ No arg means to have no executable file and no symbols."), &cmdlist); set_cmd_completer (c, filename_completer); } c = add_cmd ("exec-file", class_files, exec_file_command, _("\ Use FILE as program for getting contents of pure memory.\n\ If FILE cannot be found as specified, your execution directory path\n\ is searched for a command of that name.\n\ No arg means have no executable file."), &cmdlist); set_cmd_completer (c, filename_completer); add_com ("section", class_files, set_section_command, _("\ Change the base address of section SECTION of the exec file to ADDR.\n\ This can be used if the exec file does not contain section addresses,\n\ (such as in the a.out format), or when the addresses specified in the\n\ file itself are wrong. Each section must be changed separately. The\n\ ``info files'' command lists all the sections and their addresses.")); add_setshow_boolean_cmd ("write", class_support, &write_files, _("\ Set writing into executable and core files."), _("\ Show writing into executable and core files."), NULL, NULL, show_write_files, &setlist, &showlist); add_target_with_completer (&exec_ops, filename_completer); } static char * exec_make_note_section (bfd *obfd, int *note_size) { error (_("Can't create a corefile")); }