• Paul Eggert's avatar
    Use SAFE_ALLOCA etc. to avoid unbounded stack allocation. · b3bf18b3
    Paul Eggert authored
    This follows up on the recent thread in emacs-devel on alloca; see:
    http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00042.html
    This patch also cleans up alloca-related glitches noted while
    examining the code looking for unbounded alloca.
    * alloc.c (listn):
    * callproc.c (init_callproc):
    Rewrite to avoid need for alloca.
    * buffer.c (mouse_face_overlay_overlaps)
    (report_overlay_modification):
    * buffer.h (GET_OVERLAYS_AT):
    * coding.c (make_subsidiaries):
    * doc.c (Fsnarf_documentation):
    * editfns.c (Fuser_full_name):
    * fileio.c (Ffile_name_directory, Fexpand_file_name)
    (search_embedded_absfilename, Fsubstitute_in_file_name):
    * fns.c (Fmake_hash_table):
    * font.c (font_vconcat_entity_vectors, font_update_drivers):
    * fontset.c (fontset_pattern_regexp, Ffontset_info):
    * frame.c (Fmake_terminal_frame, x_set_frame_parameters)
    (xrdb_get_resource, x_get_resource_string):
    * ftfont.c (ftfont_get_charset, ftfont_check_otf, ftfont_drive_otf):
    * ftxfont.c (ftxfont_draw):
    * image.c (xbm_load, xpm_load, jpeg_load_body):
    * keyboard.c (echo_add_key, menu_bar_items, tool_bar_items):
    * keymap.c (Fdescribe_buffer_bindings, describe_map):
    * lread.c (openp):
    * menu.c (digest_single_submenu, find_and_call_menu_selection)
    (find_and_return_menu_selection):
    * print.c (PRINTFINISH):
    * process.c (Fformat_network_address):
    * scroll.c (do_scrolling, do_direct_scrolling, scrolling_1):
    * search.c (search_buffer, Fmatch_data, Fregexp_quote):
    * sound.c (wav_play, au_play):
    * syntax.c (skip_chars):
    * term.c (tty_menu_activate, tty_menu_show):
    * textprop.c (get_char_property_and_overlay):
    * window.c (Fset_window_configuration):
    * xdisp.c (safe__call, next_overlay_change, vmessage)
    (compute_overhangs_and_x, draw_glyphs, note_mouse_highlight):
    * xfaces.c (face_at_buffer_position):
    * xmenu.c (x_menu_show):
    Use SAFE_ALLOCA etc. instead of plain alloca, since the
    allocation size isn't bounded.
    * callint.c (Fcall_interactively): Redo memory_full check
    so that it can be done at compile-time on some platforms.
    * coding.c (MAX_LOOKUP_MAX): New constant.
    (get_translation_table): Use it.
    * callproc.c (call_process): Use SAFE_NALLOCA instead of
    SAFE_ALLOCA, to catch integer overflows on size calculation.
    (exec_failed) [!DOS_NT]: New function.
    (child_setup) [!DOS_NT]: Use it.
    * editfns.c (Ftranspose_regions):
    Hoist USE_SAFE_ALLOC + SAFE_FREE out of 'if'.
    * editfns.c (check_translation):
    Allocate larger buffers on the heap.
    * eval.c (internal_lisp_condition_case):
    Check for MAX_ALLOCA overflow.
    * fns.c (sort_vector): Use SAFE_ALLOCA_LISP rather than Fmake_vector.
    (Fbase64_encode_region, Fbase64_decode_region):
    Avoid unnecessary calls to SAFE_FREE before 'error'.
    * buffer.c (mouse_face_overlay_overlaps):
    * editfns.c (Fget_pos_property, check_translation):
    * eval.c (Ffuncall):
    * font.c (font_unparse_xlfd, font_find_for_lface):
    * ftfont.c (ftfont_drive_otf):
    * keyboard.c (echo_add_key, read_decoded_event_from_main_queue)
    (menu_bar_items, tool_bar_items):
    * sound.c (Fplay_sound_internal):
    * xdisp.c (load_overlay_strings, dump_glyph_row):
    Use an ordinary auto buffer rather than alloca, since the
    allocation size is fixed and small.
    * ftfont.c: Include <c-strcase.h>.
    (matching_prefix): New function.
    (get_adstyle_property): Use it, to avoid need for alloca.
    * keyboard.c (echo_add_key):
    * keymap.c (describe_map): Use ptrdiff_t, not int.
    * keyboard.c (echo_add_key): Prefer sizeof to strlen.
    * keymap.c (Fdescribe_buffer_bindings): Use SBYTES, not SCHARS,
    when counting bytes.
    * lisp.h (xlispstrdupa): Remove, replacing with ...
    (SAFE_ALLOCA_STRING): ... new macro with different API.
    This fixes a portability problem, namely, alloca result
    passed to another function.  All uses changed.
    (SAFE_ALLOCA, SAFE_ALLOCA_LISP): Check for MAX_ALLOCA,
    not MAX_ALLOCA - 1.
    * regex.c (REGEX_USE_SAFE_ALLOCA, REGEX_SAFE_FREE)
    (REGEX_ALLOCATE): New macros.
    (REGEX_REALLOCATE, REGEX_ALLOCATE_STACK, REGEX_REALLOCATE_STACK)
    (REGEX_FREE_STACK, FREE_VARIABLES, re_match_2_internal):
    Use them.
    * xdisp.c (message3): Use SAFE_ALLOCA_STRING rather than doing it
    by hand.
    (decode_mode_spec_coding): Store directly into buf rather than
    into an alloca temporary and copying the temporary to the buf.
    
    Fixes: debbugs:18410
    b3bf18b3
print.c 67.2 KB