gdb/event-top.c - gdb

Global variables defined

Data types defined

Functions defined

Macros defined

Source code

  1. /* Top level stuff for GDB, the GNU debugger.

  3.    Copyright (C) 1999-2015 Free Software Foundation, Inc.

  5.    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.

  7.    This file is part of GDB.

  9.    This program is free software; you can redistribute it and/or modify
  10.    it under the terms of the GNU General Public License as published by
  11.    the Free Software Foundation; either version 3 of the License, or
  12.    (at your option) any later version.

  14.    This program is distributed in the hope that it will be useful,
  15.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17.    GNU General Public License for more details.

  19.    You should have received a copy of the GNU General Public License
  20.    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

  22. #include "defs.h"
  23. #include "top.h"
  24. #include "inferior.h"
  25. #include "infrun.h"
  26. #include "target.h"
  27. #include "terminal.h"                /* for job_control */
  28. #include "event-loop.h"
  29. #include "event-top.h"
  30. #include "interps.h"
  31. #include <signal.h>
  32. #include "cli/cli-script.h"     /* for reset_command_nest_depth */
  33. #include "main.h"
  34. #include "gdbthread.h"
  35. #include "observer.h"
  36. #include "continuations.h"
  37. #include "gdbcmd.h"                /* for dont_repeat() */
  38. #include "annotate.h"
  39. #include "maint.h"

  41. /* readline include files.  */
  42. #include "readline/readline.h"
  43. #include "readline/history.h"

  45. /* readline defines this.  */
  46. ‌#undef savestring

  48. static void rl_callback_read_char_wrapper (gdb_client_data client_data);
  49. static void command_line_handler (char *rl);
  50. static void change_line_handler (void);
  51. static void command_handler (char *command);
  52. static char *top_level_prompt (void);

  54. /* Signal handlers.  */
  55. #ifdef SIGQUIT
  56. static void handle_sigquit (int sig);
  57. #endif
  58. #ifdef SIGHUP
  59. static void handle_sighup (int sig);
  60. #endif
  61. static void handle_sigfpe (int sig);

  63. /* Functions to be invoked by the event loop in response to
  64.    signals.  */
  65. #if defined (SIGQUIT) || defined (SIGHUP)
  66. static void async_do_nothing (gdb_client_data);
  67. #endif
  68. #ifdef SIGHUP
  69. static void async_disconnect (gdb_client_data);
  70. #endif
  71. static void async_float_handler (gdb_client_data);
  72. #ifdef STOP_SIGNAL
  73. static void async_stop_sig (gdb_client_data);
  74. #endif
  75. static void async_sigterm_handler (gdb_client_data arg);

  77. /* Readline offers an alternate interface, via callback
  78.    functions.  These are all included in the file callback.c in the
  79.    readline distribution.  This file provides (mainly) a function, which
  80.    the event loop uses as callback (i.e. event handler) whenever an event
  81.    is detected on the standard input file descriptor.
  82.    readline_callback_read_char is called (by the GDB event loop) whenever
  83.    there is a new character ready on the input stream.  This function
  84.    incrementally builds a buffer internal to readline where it
  85.    accumulates the line read up to the point of invocation.  In the
  86.    special case in which the character read is newline, the function
  87.    invokes a GDB supplied callback routine, which does the processing of
  88.    a full command line.  This latter routine is the asynchronous analog
  89.    of the old command_line_input in gdb.  Instead of invoking (and waiting
  90.    for) readline to read the command line and pass it back to
  91.    command_loop for processing, the new command_line_handler function has
  92.    the command line already available as its parameter.  INPUT_HANDLER is
  93.    to be set to the function that readline will invoke when a complete
  94.    line of input is ready.  CALL_READLINE is to be set to the function
  95.    that readline offers as callback to the event_loop.  */

  97. ‌void (*input_handler) (char *);
  98. ‌void (*call_readline) (gdb_client_data);

  100. /* Important variables for the event loop.  */

  102. /* This is used to determine if GDB is using the readline library or
  103.    its own simplified form of readline.  It is used by the asynchronous
  104.    form of the set editing command.
  105.    ezannoni: as of 1999-04-29 I expect that this
  106.    variable will not be used after gdb is changed to use the event
  107.    loop as default engine, and event-top.c is merged into top.c.  */
  108. ‌int async_command_editing_p;

  110. /* This is the annotation suffix that will be used when the
  111.    annotation_level is 2.  */
  112. ‌char *async_annotation_suffix;

  114. /* This is used to display the notification of the completion of an
  115.    asynchronous execution command.  */
  116. ‌int exec_done_display_p = 0;

  118. /* This is the file descriptor for the input stream that GDB uses to
  119.    read commands from.  */
  120. ‌int input_fd;

  122. /* Used by the stdin event handler to compensate for missed stdin events.
  123.    Setting this to a non-zero value inside an stdin callback makes the callback
  124.    run again.  */
  125. ‌int call_stdin_event_handler_again_p;

  127. /* Signal handling variables.  */
  128. /* Each of these is a pointer to a function that the event loop will
  129.    invoke if the corresponding signal has received.  The real signal
  130.    handlers mark these functions as ready to be executed and the event
  131.    loop, in a later iteration, calls them.  See the function
  132.    invoke_async_signal_handler.  */
  133. ‌static struct async_signal_handler *sigint_token;
  134. #ifdef SIGHUP
  135. ‌static struct async_signal_handler *sighup_token;
  136. #endif
  137. #ifdef SIGQUIT
  138. ‌static struct async_signal_handler *sigquit_token;
  139. #endif
  140. ‌static struct async_signal_handler *sigfpe_token;
  141. #ifdef STOP_SIGNAL
  142. ‌static struct async_signal_handler *sigtstp_token;
  143. #endif
  144. ‌static struct async_signal_handler *async_sigterm_token;

  146. /* Structure to save a partially entered command.  This is used when
  147.    the user types '\' at the end of a command line.  This is necessary
  148.    because each line of input is handled by a different call to
  149.    command_line_handler, and normally there is no state retained
  150.    between different calls.  */
  151. ‌static int more_to_come = 0;

  153. ‌struct readline_input_state
  154.   {
  155.     char *linebuffer;
  156.     char *linebuffer_ptr;
  157.   }
  158. ‌readline_input_state;

  160. /* This hook is called by rl_callback_read_char_wrapper after each
  161.    character is processed.  */
  162. ‌void (*after_char_processing_hook) (void);


  165. /* Wrapper function for calling into the readline library.  The event
  166.    loop expects the callback function to have a paramter, while
  167.    readline expects none.  */
  168. static void
  169. ‌rl_callback_read_char_wrapper (gdb_client_data client_data)
  170. {
  171.   rl_callback_read_char ();
  172.   if (after_char_processing_hook)
  173.     (*after_char_processing_hook) ();
  174. }

  176. /* Initialize all the necessary variables, start the event loop,
  177.    register readline, and stdin, start the loop.  The DATA is the
  178.    interpreter data cookie, ignored for now.  */

  180. void
  181. ‌cli_command_loop (void *data)
  182. {
  183.   display_gdb_prompt (0);

  185.   /* Now it's time to start the event loop.  */
  186.   start_event_loop ();
  187. }

  189. /* Change the function to be invoked every time there is a character
  190.    ready on stdin.  This is used when the user sets the editing off,
  191.    therefore bypassing readline, and letting gdb handle the input
  192.    itself, via gdb_readline2.  Also it is used in the opposite case in
  193.    which the user sets editing on again, by restoring readline
  194.    handling of the input.  */
  195. static void
  196. ‌change_line_handler (void)
  197. {
  198.   /* NOTE: this operates on input_fd, not instream.  If we are reading
  199.      commands from a file, instream will point to the file.  However in
  200.      async mode, we always read commands from a file with editing
  201.      off.  This means that the 'set editing on/off' will have effect
  202.      only on the interactive session.  */

  204.   if (async_command_editing_p)
  205.     {
  206.       /* Turn on editing by using readline.  */
  207.       call_readline = rl_callback_read_char_wrapper;
  208.       input_handler = command_line_handler;
  209.     }
  210.   else
  211.     {
  212.       /* Turn off editing by using gdb_readline2.  */
  213.       gdb_rl_callback_handler_remove ();
  214.       call_readline = gdb_readline2;

  216.       /* Set up the command handler as well, in case we are called as
  217.          first thing from .gdbinit.  */
  218.       input_handler = command_line_handler;
  219.     }
  220. }

  222. /* The functions below are wrappers for rl_callback_handler_remove and
  223.    rl_callback_handler_install that keep track of whether the callback
  224.    handler is installed in readline.  This is necessary because after
  225.    handling a target event of a background execution command, we may
  226.    need to reinstall the callback handler if it was removed due to a
  227.    secondary prompt.  See gdb_readline_wrapper_line.  We don't
  228.    unconditionally install the handler for every target event because
  229.    that also clears the line buffer, thus installing it while the user
  230.    is typing would lose input.  */

  232. /* Whether we've registered a callback handler with readline.  */
  233. ‌static int callback_handler_installed;

  235. /* See event-top.h, and above.  */

  237. void
  238. ‌gdb_rl_callback_handler_remove (void)
  239. {
  240.   rl_callback_handler_remove ();
  241.   callback_handler_installed = 0;
  242. }

  244. /* See event-top.h, and above.  Note this wrapper doesn't have an
  245.    actual callback parameter because we always install
  246.    INPUT_HANDLER.  */

  248. void
  249. ‌gdb_rl_callback_handler_install (const char *prompt)
  250. {
  251.   /* Calling rl_callback_handler_install resets readline's input
  252.      buffer.  Calling this when we were already processing input
  253.      therefore loses input.  */
  254.   gdb_assert (!callback_handler_installed);

  256.   rl_callback_handler_install (prompt, input_handler);
  257.   callback_handler_installed = 1;
  258. }

  260. /* See event-top.h, and above.  */

  262. void
  263. ‌gdb_rl_callback_handler_reinstall (void)
  264. {
  265.   if (!callback_handler_installed)
  266.     {
  267.       /* Passing NULL as prompt argument tells readline to not display
  268.          a prompt.  */
  269.       gdb_rl_callback_handler_install (NULL);
  270.     }
  271. }

  273. /* Displays the prompt.  If the argument NEW_PROMPT is NULL, the
  274.    prompt that is displayed is the current top level prompt.
  275.    Otherwise, it displays whatever NEW_PROMPT is as a local/secondary
  276.    prompt.

  278.    This is used after each gdb command has completed, and in the
  279.    following cases:

  281.    1. When the user enters a command line which is ended by '\'
  282.    indicating that the command will continue on the next line.  In
  283.    that case the prompt that is displayed is the empty string.

  285.    2. When the user is entering 'commands' for a breakpoint, or
  286.    actions for a tracepoint.  In this case the prompt will be '>'

  288.    3. On prompting for pagination.  */

  290. void
  291. ‌display_gdb_prompt (const char *new_prompt)
  292. {
  293.   char *actual_gdb_prompt = NULL;
  294.   struct cleanup *old_chain;

  296.   annotate_display_prompt ();

  298.   /* Reset the nesting depth used when trace-commands is set.  */
  299.   reset_command_nest_depth ();

  301.   old_chain = make_cleanup (free_current_contents, &actual_gdb_prompt);

  303.   /* Do not call the python hook on an explicit prompt change as
  304.      passed to this function, as this forms a secondary/local prompt,
  305.      IE, displayed but not set.  */
  306.   if (! new_prompt)
  307.     {
  308.       if (sync_execution)
  309.         {
  310.           /* This is to trick readline into not trying to display the
  311.              prompt.  Even though we display the prompt using this
  312.              function, readline still tries to do its own display if
  313.              we don't call rl_callback_handler_install and
  314.              rl_callback_handler_remove (which readline detects
  315.              because a global variable is not set).  If readline did
  316.              that, it could mess up gdb signal handlers for SIGINT.
  317.              Readline assumes that between calls to rl_set_signals and
  318.              rl_clear_signals gdb doesn't do anything with the signal
  319.              handlers.  Well, that's not the case, because when the
  320.              target executes we change the SIGINT signal handler.  If
  321.              we allowed readline to display the prompt, the signal
  322.              handler change would happen exactly between the calls to
  323.              the above two functions.  Calling
  324.              rl_callback_handler_remove(), does the job.  */

  326.           gdb_rl_callback_handler_remove ();
  327.           do_cleanups (old_chain);
  328.           return;
  329.         }
  330.       else
  331.         {
  332.           /* Display the top level prompt.  */
  333.           actual_gdb_prompt = top_level_prompt ();
  334.         }
  335.     }
  336.   else
  337.     actual_gdb_prompt = xstrdup (new_prompt);

  339.   if (async_command_editing_p)
  340.     {
  341.       gdb_rl_callback_handler_remove ();
  342.       gdb_rl_callback_handler_install (actual_gdb_prompt);
  343.     }
  344.   /* new_prompt at this point can be the top of the stack or the one
  345.      passed in.  It can't be NULL.  */
  346.   else
  347.     {
  348.       /* Don't use a _filtered function here.  It causes the assumed
  349.          character position to be off, since the newline we read from
  350.          the user is not accounted for.  */
  351.       fputs_unfiltered (actual_gdb_prompt, gdb_stdout);
  352.       gdb_flush (gdb_stdout);
  353.     }

  355.   do_cleanups (old_chain);
  356. }

  358. /* Return the top level prompt, as specified by "set prompt", possibly
  359.    overriden by the python gdb.prompt_hook hook, and then composed
  360.    with the prompt prefix and suffix (annotations).  The caller is
  361.    responsible for freeing the returned string.  */

  363. static char *
  364. ‌top_level_prompt (void)
  365. {
  366.   char *prefix;
  367.   char *prompt = NULL;
  368.   char *suffix;
  369.   char *composed_prompt;
  370.   size_t prompt_length;

  372.   /* Give observers a chance of changing the prompt.  E.g., the python
  373.      `gdb.prompt_hook' is installed as an observer.  */
  374.   observer_notify_before_prompt (get_prompt ());

  376.   prompt = xstrdup (get_prompt ());

  378.   if (annotation_level >= 2)
  379.     {
  380.       /* Prefix needs to have new line at end.  */
  381.       prefix = (char *) alloca (strlen (async_annotation_suffix) + 10);
  382.       strcpy (prefix, "\n\032\032pre-");
  383.       strcat (prefix, async_annotation_suffix);
  384.       strcat (prefix, "\n");

  386.       /* Suffix needs to have a new line at end and \032 \032 at
  387.          beginning.  */
  388.       suffix = (char *) alloca (strlen (async_annotation_suffix) + 6);
  389.       strcpy (suffix, "\n\032\032");
  390.       strcat (suffix, async_annotation_suffix);
  391.       strcat (suffix, "\n");
  392.     }
  393.   else
  394.     {
  395.       prefix = "";
  396.       suffix = "";
  397.     }

  399.   prompt_length = strlen (prefix) + strlen (prompt) + strlen (suffix);
  400.   composed_prompt = xmalloc (prompt_length + 1);

  402.   strcpy (composed_prompt, prefix);
  403.   strcat (composed_prompt, prompt);
  404.   strcat (composed_prompt, suffix);

  406.   xfree (prompt);

  408.   return composed_prompt;
  409. }

  411. /* When there is an event ready on the stdin file desriptor, instead
  412.    of calling readline directly throught the callback function, or
  413.    instead of calling gdb_readline2, give gdb a chance to detect
  414.    errors and do something.  */
  415. void
  416. ‌stdin_event_handler (int error, gdb_client_data client_data)
  417. {
  418.   if (error)
  419.     {
  420.       printf_unfiltered (_("error detected on stdin\n"));
  421.       delete_file_handler (input_fd);
  422.       discard_all_continuations ();
  423.       discard_all_intermediate_continuations ();
  424.       /* If stdin died, we may as well kill gdb.  */
  425.       quit_command ((char *) 0, stdin == instream);
  426.     }
  427.   else
  428.     {
  429.       do
  430.         {
  431.           call_stdin_event_handler_again_p = 0;
  432.           (*call_readline) (client_data);
  433.         } while (call_stdin_event_handler_again_p != 0);
  434.     }
  435. }

  437. /* Re-enable stdin after the end of an execution command in
  438.    synchronous mode, or after an error from the target, and we aborted
  439.    the exec operation.  */

  441. void
  442. ‌async_enable_stdin (void)
  443. {
  444.   if (sync_execution)
  445.     {
  446.       /* See NOTE in async_disable_stdin().  */
  447.       /* FIXME: cagney/1999-09-27: Call this before clearing
  448.          sync_execution.  Current target_terminal_ours() implementations
  449.          check for sync_execution before switching the terminal.  */
  450.       target_terminal_ours ();
  451.       sync_execution = 0;
  452.     }
  453. }

  455. /* Disable reads from stdin (the console) marking the command as
  456.    synchronous.  */

  458. void
  459. ‌async_disable_stdin (void)
  460. {
  461.   sync_execution = 1;
  462. }


  465. /* Handles a gdb command.  This function is called by
  466.    command_line_handler, which has processed one or more input lines
  467.    into COMMAND.  */
  468. /* NOTE: 1999-04-30 This is the asynchronous version of the command_loop
  469.    function.  The command_loop function will be obsolete when we
  470.    switch to use the event loop at every execution of gdb.  */
  471. static void
  472. ‌command_handler (char *command)
  473. {
  474.   int stdin_is_tty = ISATTY (stdin);
  475.   struct cleanup *stat_chain;

  477.   clear_quit_flag ();
  478.   if (instream == stdin && stdin_is_tty)
  479.     reinitialize_more_filter ();

  481.   /* If readline returned a NULL command, it means that the connection
  482.      with the terminal is gone.  This happens at the end of a
  483.      testsuite run, after Expect has hung up but GDB is still alive.
  484.      In such a case, we just quit gdb killing the inferior program
  485.      too.  */
  486.   if (command == 0)
  487.     {
  488.       printf_unfiltered ("quit\n");
  489.       execute_command ("quit", stdin == instream);
  490.     }

  492.   stat_chain = make_command_stats_cleanup (1);

  494.   execute_command (command, instream == stdin);

  496.   /* Do any commands attached to breakpoint we stopped at.  */
  497.   bpstat_do_actions ();

  499.   do_cleanups (stat_chain);
  500. }

  502. /* Handle a complete line of input.  This is called by the callback
  503.    mechanism within the readline library.  Deal with incomplete
  504.    commands as well, by saving the partial input in a global
  505.    buffer.  */

  507. /* NOTE: 1999-04-30 This is the asynchronous version of the
  508.    command_line_input function; command_line_input will become
  509.    obsolete once we use the event loop as the default mechanism in
  510.    GDB.  */
  511. static void
  512. ‌command_line_handler (char *rl)
  513. {
  514.   static char *linebuffer = 0;
  515.   static unsigned linelength = 0;
  516.   char *p;
  517.   char *p1;
  518.   char *nline;
  519.   int repeat = (instream == stdin);

  521.   if (annotation_level > 1 && instream == stdin)
  522.     {
  523.       printf_unfiltered (("\n\032\032post-"));
  524.       puts_unfiltered (async_annotation_suffix);
  525.       printf_unfiltered (("\n"));
  526.     }

  528.   if (linebuffer == 0)
  529.     {
  530.       linelength = 80;
  531.       linebuffer = (char *) xmalloc (linelength);
  532.       linebuffer[0] = '\0';
  533.     }

  535.   p = linebuffer;

  537.   if (more_to_come)
  538.     {
  539.       strcpy (linebuffer, readline_input_state.linebuffer);
  540.       p = readline_input_state.linebuffer_ptr;
  541.       xfree (readline_input_state.linebuffer);
  542.       more_to_come = 0;
  543.     }

  545. #ifdef STOP_SIGNAL
  546.   if (job_control)
  547.     signal (STOP_SIGNAL, handle_stop_sig);
  548. #endif

  550.   /* Make sure that all output has been output.  Some machines may let
  551.      you get away with leaving out some of the gdb_flush, but not
  552.      all.  */
  553.   wrap_here ("");
  554.   gdb_flush (gdb_stdout);
  555.   gdb_flush (gdb_stderr);

  557.   if (source_file_name != NULL)
  558.     ++source_line_number;

  560.   /* If we are in this case, then command_handler will call quit
  561.      and exit from gdb.  */
  562.   if (!rl || rl == (char *) EOF)
  563.     {
  564.       command_handler (0);
  565.       return;                        /* Lint.  */
  566.     }
  567.   if (strlen (rl) + 1 + (p - linebuffer) > linelength)
  568.     {
  569.       linelength = strlen (rl) + 1 + (p - linebuffer);
  570.       nline = (char *) xrealloc (linebuffer, linelength);
  571.       p += nline - linebuffer;
  572.       linebuffer = nline;
  573.     }
  574.   p1 = rl;
  575.   /* Copy line.  Don't copy null at end.  (Leaves line alone
  576.      if this was just a newline).  */
  577.   while (*p1)
  578.     *p++ = *p1++;

  580.   xfree (rl);                        /* Allocated in readline.  */

  582.   if (p > linebuffer && *(p - 1) == '\\')
  583.     {
  584.       *p = '\0';
  585.       p--;                        /* Put on top of '\'.  */

  587.       readline_input_state.linebuffer = xstrdup (linebuffer);
  588.       readline_input_state.linebuffer_ptr = p;

  590.       /* We will not invoke a execute_command if there is more
  591.          input expected to complete the command.  So, we need to
  592.          print an empty prompt here.  */
  593.       more_to_come = 1;
  594.       display_gdb_prompt ("");
  595.       return;
  596.     }

  598. #ifdef STOP_SIGNAL
  599.   if (job_control)
  600.     signal (STOP_SIGNAL, SIG_DFL);
  601. #endif

  603. ‌#define SERVER_COMMAND_LENGTH 7
  604.   server_command =
  605.     (p - linebuffer > SERVER_COMMAND_LENGTH)
  606.     && strncmp (linebuffer, "server ", SERVER_COMMAND_LENGTH) == 0;
  607.   if (server_command)
  608.     {
  609.       /* Note that we don't set `line'.  Between this and the check in
  610.          dont_repeat, this insures that repeating will still do the
  611.          right thing.  */
  612.       *p = '\0';
  613.       command_handler (linebuffer + SERVER_COMMAND_LENGTH);
  614.       display_gdb_prompt (0);
  615.       return;
  616.     }

  618.   /* Do history expansion if that is wished.  */
  619.   if (history_expansion_p && instream == stdin
  620.       && ISATTY (instream))
  621.     {
  622.       char *history_value;
  623.       int expanded;

  625.       *p = '\0';                /* Insert null now.  */
  626.       expanded = history_expand (linebuffer, &history_value);
  627.       if (expanded)
  628.         {
  629.           /* Print the changes.  */
  630.           printf_unfiltered ("%s\n", history_value);

  632.           /* If there was an error, call this function again.  */
  633.           if (expanded < 0)
  634.             {
  635.               xfree (history_value);
  636.               return;
  637.             }
  638.           if (strlen (history_value) > linelength)
  639.             {
  640.               linelength = strlen (history_value) + 1;
  641.               linebuffer = (char *) xrealloc (linebuffer, linelength);
  642.             }
  643.           strcpy (linebuffer, history_value);
  644.           p = linebuffer + strlen (linebuffer);
  645.         }
  646.       xfree (history_value);
  647.     }

  649.   /* If we just got an empty line, and that is supposed to repeat the
  650.      previous command, return the value in the global buffer.  */
  651.   if (repeat && p == linebuffer && *p != '\\')
  652.     {
  653.       command_handler (saved_command_line);
  654.       display_gdb_prompt (0);
  655.       return;
  656.     }

  658.   for (p1 = linebuffer; *p1 == ' ' || *p1 == '\t'; p1++);
  659.   if (repeat && !*p1)
  660.     {
  661.       command_handler (saved_command_line);
  662.       display_gdb_prompt (0);
  663.       return;
  664.     }

  666.   *p = 0;

  668.   /* Add line to history if appropriate.  */
  669.   if (*linebuffer && input_from_terminal_p ())
  670.     add_history (linebuffer);

  672.   /* Note: lines consisting solely of comments are added to the command
  673.      history.  This is useful when you type a command, and then
  674.      realize you don't want to execute it quite yet.  You can comment
  675.      out the command and then later fetch it from the value history
  676.      and remove the '#'.  The kill ring is probably better, but some
  677.      people are in the habit of commenting things out.  */
  678.   if (*p1 == '#')
  679.     *p1 = '\0';                        /* Found a comment.  */

  681.   /* Save into global buffer if appropriate.  */
  682.   if (repeat)
  683.     {
  684.       if (linelength > saved_command_line_size)
  685.         {
  686.           saved_command_line = xrealloc (saved_command_line, linelength);
  687.           saved_command_line_size = linelength;
  688.         }
  689.       strcpy (saved_command_line, linebuffer);
  690.       if (!more_to_come)
  691.         {
  692.           command_handler (saved_command_line);
  693.           display_gdb_prompt (0);
  694.         }
  695.       return;
  696.     }

  698.   command_handler (linebuffer);
  699.   display_gdb_prompt (0);
  700.   return;
  701. }

  703. /* Does reading of input from terminal w/o the editing features
  704.    provided by the readline library.  */

  706. /* NOTE: 1999-04-30 Asynchronous version of gdb_readline; gdb_readline
  707.    will become obsolete when the event loop is made the default
  708.    execution for gdb.  */
  709. void
  710. ‌gdb_readline2 (gdb_client_data client_data)
  711. {
  712.   int c;
  713.   char *result;
  714.   int input_index = 0;
  715.   int result_size = 80;
  716.   static int done_once = 0;

  718.   /* Unbuffer the input stream, so that, later on, the calls to fgetc
  719.      fetch only one char at the time from the stream.  The fgetc's will
  720.      get up to the first newline, but there may be more chars in the
  721.      stream after '\n'.  If we buffer the input and fgetc drains the
  722.      stream, getting stuff beyond the newline as well, a select, done
  723.      afterwards will not trigger.  */
  724.   if (!done_once && !ISATTY (instream))
  725.     {
  726.       setbuf (instream, NULL);
  727.       done_once = 1;
  728.     }

  730.   result = (char *) xmalloc (result_size);

  732.   /* We still need the while loop here, even though it would seem
  733.      obvious to invoke gdb_readline2 at every character entered.  If
  734.      not using the readline library, the terminal is in cooked mode,
  735.      which sends the characters all at once.  Poll will notice that the
  736.      input fd has changed state only after enter is pressed.  At this
  737.      point we still need to fetch all the chars entered.  */

  739.   while (1)
  740.     {
  741.       /* Read from stdin if we are executing a user defined command.
  742.          This is the right thing for prompt_for_continue, at least.  */
  743.       c = fgetc (instream ? instream : stdin);

  745.       if (c == EOF)
  746.         {
  747.           if (input_index > 0)
  748.             /* The last line does not end with a newline.  Return it,
  749.                and if we are called again fgetc will still return EOF
  750.                and we'll return NULL then.  */
  751.             break;
  752.           xfree (result);
  753.           (*input_handler) (0);
  754.           return;
  755.         }

  757.       if (c == '\n')
  758.         {
  759.           if (input_index > 0 && result[input_index - 1] == '\r')
  760.             input_index--;
  761.           break;
  762.         }

  764.       result[input_index++] = c;
  765.       while (input_index >= result_size)
  766.         {
  767.           result_size *= 2;
  768.           result = (char *) xrealloc (result, result_size);
  769.         }
  770.     }

  772.   result[input_index++] = '\0';
  773.   (*input_handler) (result);
  774. }


  777. /* Initialization of signal handlers and tokens.  There is a function
  778.    handle_sig* for each of the signals GDB cares about.  Specifically:
  779.    SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH.  These
  780.    functions are the actual signal handlers associated to the signals
  781.    via calls to signal().  The only job for these functions is to
  782.    enqueue the appropriate event/procedure with the event loop.  Such
  783.    procedures are the old signal handlers.  The event loop will take
  784.    care of invoking the queued procedures to perform the usual tasks
  785.    associated with the reception of the signal.  */
  786. /* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
  787.    init_signals will become obsolete as we move to have to event loop
  788.    as the default for gdb.  */
  789. void
  790. ‌async_init_signals (void)
  791. {
  792.   signal (SIGINT, handle_sigint);
  793.   sigint_token =
  794.     create_async_signal_handler (async_request_quit, NULL);
  795.   signal (SIGTERM, handle_sigterm);
  796.   async_sigterm_token
  797.     = create_async_signal_handler (async_sigterm_handler, NULL);

  799.   /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
  800.      to the inferior and breakpoints will be ignored.  */
  801. #ifdef SIGTRAP
  802.   signal (SIGTRAP, SIG_DFL);
  803. #endif

  805. #ifdef SIGQUIT
  806.   /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
  807.      passed to the inferior, which we don't want.  It would be
  808.      possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
  809.      on BSD4.3 systems using vfork, that can affect the
  810.      GDB process as well as the inferior (the signal handling tables
  811.      might be in memory, shared between the two).  Since we establish
  812.      a handler for SIGQUIT, when we call exec it will set the signal
  813.      to SIG_DFL for us.  */
  814.   signal (SIGQUIT, handle_sigquit);
  815.   sigquit_token =
  816.     create_async_signal_handler (async_do_nothing, NULL);
  817. #endif
  818. #ifdef SIGHUP
  819.   if (signal (SIGHUP, handle_sighup) != SIG_IGN)
  820.     sighup_token =
  821.       create_async_signal_handler (async_disconnect, NULL);
  822.   else
  823.     sighup_token =
  824.       create_async_signal_handler (async_do_nothing, NULL);
  825. #endif
  826.   signal (SIGFPE, handle_sigfpe);
  827.   sigfpe_token =
  828.     create_async_signal_handler (async_float_handler, NULL);

  830. #ifdef STOP_SIGNAL
  831.   sigtstp_token =
  832.     create_async_signal_handler (async_stop_sig, NULL);
  833. #endif
  834. }

  836. /* Tell the event loop what to do if SIGINT is received.
  837.    See event-signal.c.  */
  838. void
  839. ‌handle_sigint (int sig)
  840. {
  841.   signal (sig, handle_sigint);

  843.   /* We could be running in a loop reading in symfiles or something so
  844.      it may be quite a while before we get back to the event loop.  So
  845.      set quit_flag to 1 here.  Then if QUIT is called before we get to
  846.      the event loop, we will unwind as expected.  */

  848.   set_quit_flag ();

  850.   /* If immediate_quit is set, we go ahead and process the SIGINT right
  851.      away, even if we usually would defer this to the event loop.  The
  852.      assumption here is that it is safe to process ^C immediately if
  853.      immediate_quit is set.  If we didn't, SIGINT would be really
  854.      processed only the next time through the event loop.  To get to
  855.      that point, though, the command that we want to interrupt needs to
  856.      finish first, which is unacceptable.  If immediate quit is not set,
  857.      we process SIGINT the next time through the loop, which is fine.  */
  858.   gdb_call_async_signal_handler (sigint_token, immediate_quit);
  859. }

  861. /* Handle GDB exit upon receiving SIGTERM if target_can_async_p ().  */

  863. static void
  864. ‌async_sigterm_handler (gdb_client_data arg)
  865. {
  866.   quit_force (NULL, stdin == instream);
  867. }

  869. /* See defs.h.  */
  870. ‌volatile int sync_quit_force_run;

  872. /* Quit GDB if SIGTERM is received.
  873.    GDB would quit anyway, but this way it will clean up properly.  */
  874. void
  875. ‌handle_sigterm (int sig)
  876. {
  877.   signal (sig, handle_sigterm);

  879.   /* Call quit_force in a signal safe way.
  880.      quit_force itself is not signal safe.  */
  881.   if (target_can_async_p ())
  882.     mark_async_signal_handler (async_sigterm_token);
  883.   else
  884.     {
  885.       sync_quit_force_run = 1;
  886.       set_quit_flag ();
  887.     }
  888. }

  890. /* Do the quit.  All the checks have been done by the caller.  */
  891. void
  892. ‌async_request_quit (gdb_client_data arg)
  893. {
  894.   /* If the quit_flag has gotten reset back to 0 by the time we get
  895.      back here, that means that an exception was thrown to unwind the
  896.      current command before we got back to the event loop.  So there
  897.      is no reason to call quit again here.  */

  899.   if (check_quit_flag ())
  900.     quit ();
  901. }

  903. #ifdef SIGQUIT
  904. /* Tell the event loop what to do if SIGQUIT is received.
  905.    See event-signal.c.  */
  906. static void
  907. ‌handle_sigquit (int sig)
  908. {
  909.   mark_async_signal_handler (sigquit_token);
  910.   signal (sig, handle_sigquit);
  911. }
  912. #endif

  914. #if defined (SIGQUIT) || defined (SIGHUP)
  915. /* Called by the event loop in response to a SIGQUIT or an
  916.    ignored SIGHUP.  */
  917. static void
  918. ‌async_do_nothing (gdb_client_data arg)
  919. {
  920.   /* Empty function body.  */
  921. }
  922. #endif

  924. #ifdef SIGHUP
  925. /* Tell the event loop what to do if SIGHUP is received.
  926.    See event-signal.c.  */
  927. static void
  928. ‌handle_sighup (int sig)
  929. {
  930.   mark_async_signal_handler (sighup_token);
  931.   signal (sig, handle_sighup);
  932. }

  934. /* Called by the event loop to process a SIGHUP.  */
  935. static void
  936. ‌async_disconnect (gdb_client_data arg)
  937. {
  938.   volatile struct gdb_exception exception;

  940.   TRY_CATCH (exception, RETURN_MASK_ALL)
  941.     {
  942.       quit_cover ();
  943.     }

  945.   if (exception.reason < 0)
  946.     {
  947.       fputs_filtered ("Could not kill the program being debugged",
  948.                       gdb_stderr);
  949.       exception_print (gdb_stderr, exception);
  950.     }

  952.   TRY_CATCH (exception, RETURN_MASK_ALL)
  953.     {
  954.       pop_all_targets ();
  955.     }

  957.   signal (SIGHUP, SIG_DFL);        /*FIXME: ???????????  */
  958.   raise (SIGHUP);
  959. }
  960. #endif

  962. #ifdef STOP_SIGNAL
  963. void
  964. ‌handle_stop_sig (int sig)
  965. {
  966.   mark_async_signal_handler (sigtstp_token);
  967.   signal (sig, handle_stop_sig);
  968. }

  970. static void
  971. ‌async_stop_sig (gdb_client_data arg)
  972. {
  973.   char *prompt = get_prompt ();

  975. #if STOP_SIGNAL == SIGTSTP
  976.   signal (SIGTSTP, SIG_DFL);
  977. #if HAVE_SIGPROCMASK
  978.   {
  979.     sigset_t zero;

  981.     sigemptyset (&zero);
  982.     sigprocmask (SIG_SETMASK, &zero, 0);
  983.   }
  984. #elif HAVE_SIGSETMASK
  985.   sigsetmask (0);
  986. #endif
  987.   raise (SIGTSTP);
  988.   signal (SIGTSTP, handle_stop_sig);
  989. #else
  990.   signal (STOP_SIGNAL, handle_stop_sig);
  991. #endif
  992.   printf_unfiltered ("%s", prompt);
  993.   gdb_flush (gdb_stdout);

  995.   /* Forget about any previous command -- null line now will do
  996.      nothing.  */
  997.   dont_repeat ();
  998. }
  999. #endif /* STOP_SIGNAL */

  1001. /* Tell the event loop what to do if SIGFPE is received.
  1002.    See event-signal.c.  */
  1003. static void
  1004. ‌handle_sigfpe (int sig)
  1005. {
  1006.   mark_async_signal_handler (sigfpe_token);
  1007.   signal (sig, handle_sigfpe);
  1008. }

  1010. /* Event loop will call this functin to process a SIGFPE.  */
  1011. static void
  1012. ‌async_float_handler (gdb_client_data arg)
  1013. {
  1014.   /* This message is based on ANSI C, section 4.7.  Note that integer
  1015.      divide by zero causes this, so "float" is a misnomer.  */
  1016.   error (_("Erroneous arithmetic operation."));
  1017. }


  1020. /* Called by do_setshow_command.  */
  1021. void
  1022. ‌set_async_editing_command (char *args, int from_tty,
  1023.                            struct cmd_list_element *c)
  1024. {
  1025.   change_line_handler ();
  1026. }

  1028. /* Set things up for readline to be invoked via the alternate
  1029.    interface, i.e. via a callback function (rl_callback_read_char),
  1030.    and hook up instream to the event loop.  */
  1031. void
  1032. ‌gdb_setup_readline (void)
  1033. {
  1034.   /* This function is a noop for the sync case.  The assumption is
  1035.      that the sync setup is ALL done in gdb_init, and we would only
  1036.      mess it up here.  The sync stuff should really go away over
  1037.      time.  */
  1038.   if (!batch_silent)
  1039.     gdb_stdout = stdio_fileopen (stdout);
  1040.   gdb_stderr = stderr_fileopen ();
  1041.   gdb_stdlog = gdb_stderr;  /* for moment */
  1042.   gdb_stdtarg = gdb_stderr; /* for moment */
  1043.   gdb_stdtargerr = gdb_stderr; /* for moment */

  1045.   /* If the input stream is connected to a terminal, turn on
  1046.      editing.  */
  1047.   if (ISATTY (instream))
  1048.     {
  1049.       /* Tell gdb that we will be using the readline library.  This
  1050.          could be overwritten by a command in .gdbinit like 'set
  1051.          editing on' or 'off'.  */
  1052.       async_command_editing_p = 1;

  1054.       /* When a character is detected on instream by select or poll,
  1055.          readline will be invoked via this callback function.  */
  1056.       call_readline = rl_callback_read_char_wrapper;
  1057.     }
  1058.   else
  1059.     {
  1060.       async_command_editing_p = 0;
  1061.       call_readline = gdb_readline2;
  1062.     }

  1064.   /* When readline has read an end-of-line character, it passes the
  1065.      complete line to gdb for processing; command_line_handler is the
  1066.      function that does this.  */
  1067.   input_handler = command_line_handler;

  1069.   /* Tell readline to use the same input stream that gdb uses.  */
  1070.   rl_instream = instream;

  1072.   /* Get a file descriptor for the input stream, so that we can
  1073.      register it with the event loop.  */
  1074.   input_fd = fileno (instream);

  1076.   /* Now we need to create the event sources for the input file
  1077.      descriptor.  */
  1078.   /* At this point in time, this is the only event source that we
  1079.      register with the even loop.  Another source is going to be the
  1080.      target program (inferior), but that must be registered only when
  1081.      it actually exists (I.e. after we say 'run' or after we connect
  1082.      to a remote target.  */
  1083.   add_file_handler (input_fd, stdin_event_handler, 0);
  1084. }

  1086. /* Disable command input through the standard CLI channels.  Used in
  1087.    the suspend proc for interpreters that use the standard gdb readline
  1088.    interface, like the cli & the mi.  */
  1089. void
  1090. ‌gdb_disable_readline (void)
  1091. {
  1092.   /* FIXME - It is too heavyweight to delete and remake these every
  1093.      time you run an interpreter that needs readline.  It is probably
  1094.      better to have the interpreters cache these, which in turn means
  1095.      that this needs to be moved into interpreter specific code.  */

  1097. #if 0
  1098.   ui_file_delete (gdb_stdout);
  1099.   ui_file_delete (gdb_stderr);
  1100.   gdb_stdlog = NULL;
  1101.   gdb_stdtarg = NULL;
  1102.   gdb_stdtargerr = NULL;
  1103. #endif

  1105.   gdb_rl_callback_handler_remove ();
  1106.   delete_file_handler (input_fd);
  1107. }