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event-top.c
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/* Top level stuff for GDB, the GNU debugger.
Copyright (C) 1999-2024 Free Software Foundation, Inc.
Written by Elena Zannoni <[email protected]> of Cygnus Solutions.
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 <http://www.gnu.org/licenses/>. */
#include "exceptions.h"
#include "gdbsupport/job-control.h"
#include "run-on-main-thread.h"
#include "top.h"
#include "ui.h"
#include "inferior.h"
#include "infrun.h"
#include "target.h"
#include "terminal.h"
#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "interps.h"
#include <signal.h>
#include "cli/cli-script.h"
#include "main.h"
#include "gdbthread.h"
#include "observable.h"
#include "cli/cli-cmds.h"
#include "annotate.h"
#include "maint.h"
#include "ser-event.h"
#include "gdbsupport/gdb_select.h"
#include "gdbsupport/gdb-sigmask.h"
#include "async-event.h"
#include "bt-utils.h"
#include "pager.h"
/* readline include files. */
#include "readline/readline.h"
#include "readline/history.h"
#ifdef TUI
#include "tui/tui.h"
#endif
/* readline defines this. */
#undef savestring
static std::string top_level_prompt ();
/* Signal handlers. */
#ifdef SIGQUIT
static void handle_sigquit (int sig);
#endif
#ifdef SIGHUP
static void handle_sighup (int sig);
#endif
/* Functions to be invoked by the event loop in response to
signals. */
#if defined (SIGQUIT) || defined (SIGHUP)
static void async_do_nothing (gdb_client_data);
#endif
#ifdef SIGHUP
static void async_disconnect (gdb_client_data);
#endif
#ifdef SIGTSTP
static void async_sigtstp_handler (gdb_client_data);
#endif
static void async_sigterm_handler (gdb_client_data arg);
/* Instead of invoking (and waiting for) readline to read the command
line and pass it back for processing, we use readline's alternate
interface, via callback functions, so that the event loop can react
to other event sources while we wait for input. */
/* Important variables for the event loop. */
/* This is used to determine if GDB is using the readline library or
its own simplified form of readline. It is used by the asynchronous
form of the set editing command.
ezannoni: as of 1999-04-29 I expect that this
variable will not be used after gdb is changed to use the event
loop as default engine, and event-top.c is merged into top.c. */
bool set_editing_cmd_var;
/* This is used to display the notification of the completion of an
asynchronous execution command. */
bool exec_done_display_p = false;
/* Used by the stdin event handler to compensate for missed stdin events.
Setting this to a non-zero value inside an stdin callback makes the callback
run again. */
int call_stdin_event_handler_again_p;
/* When true GDB will produce a minimal backtrace when a fatal signal is
reached (within GDB code). */
static bool bt_on_fatal_signal = GDB_PRINT_INTERNAL_BACKTRACE_INIT_ON;
/* Implement 'maintenance show backtrace-on-fatal-signal'. */
static void
show_bt_on_fatal_signal (struct ui_file *file, int from_tty,
struct cmd_list_element *cmd, const char *value)
{
gdb_printf (file, _("Backtrace on a fatal signal is %s.\n"), value);
}
/* Signal handling variables. */
/* Each of these is a pointer to a function that the event loop will
invoke if the corresponding signal has received. The real signal
handlers mark these functions as ready to be executed and the event
loop, in a later iteration, calls them. See the function
invoke_async_signal_handler. */
static struct async_signal_handler *sigint_token;
#ifdef SIGHUP
static struct async_signal_handler *sighup_token;
#endif
#ifdef SIGQUIT
static struct async_signal_handler *sigquit_token;
#endif
#ifdef SIGTSTP
static struct async_signal_handler *sigtstp_token;
#endif
static struct async_signal_handler *async_sigterm_token;
/* This hook is called by gdb_rl_callback_read_char_wrapper after each
character is processed. */
void (*after_char_processing_hook) (void);
#if RL_VERSION_MAJOR == 7
extern "C" void _rl_signal_handler (int);
#endif
/* Wrapper function for calling into the readline library. This takes
care of a couple things:
- The event loop expects the callback function to have a parameter,
while readline expects none.
- Propagation of GDB exceptions/errors thrown from INPUT_HANDLER
across readline requires special handling.
On the exceptions issue:
DWARF-based unwinding cannot cross code built without -fexceptions.
Any exception that tries to propagate through such code will fail
and the result is a call to std::terminate. While some ABIs, such
as x86-64, require all code to be built with exception tables,
others don't.
This is a problem when GDB calls some non-EH-aware C library code,
that calls into GDB again through a callback, and that GDB callback
code throws a C++ exception. Turns out this is exactly what
happens with GDB's readline callback.
In such cases, we must catch and save any C++ exception that might
be thrown from the GDB callback before returning to the
non-EH-aware code. When the non-EH-aware function itself returns
back to GDB, we then rethrow the original C++ exception.
In the readline case however, the right thing to do is to longjmp
out of the callback, rather than do a normal return -- there's no
way for the callback to return to readline an indication that an
error happened, so a normal return would have rl_callback_read_char
potentially continue processing further input, redisplay the
prompt, etc. Instead of raw setjmp/longjmp however, we use our
sjlj-based TRY/CATCH mechanism, which knows to handle multiple
levels of active setjmp/longjmp frames, needed in order to handle
the readline callback recursing, as happens with e.g., secondary
prompts / queries, through gdb_readline_wrapper. This must be
noexcept in order to avoid problems with mixing sjlj and
(sjlj-based) C++ exceptions. */
static struct gdb_exception
gdb_rl_callback_read_char_wrapper_sjlj ()
{
struct gdb_exception gdb_expt;
/* C++ exceptions can't normally be thrown across readline (unless
it is built with -fexceptions, but it won't by default on many
ABIs). So we instead wrap the readline call with a sjlj-based
TRY/CATCH, and rethrow the GDB exception once back in GDB. */
TRY_SJLJ
{
rl_callback_read_char ();
#if RL_VERSION_MAJOR >= 8
/* It can happen that readline (while in rl_callback_read_char)
received a signal, but didn't handle it yet. Make sure it's handled
now. If we don't do that we run into two related problems:
- we have to wait for another event triggering
rl_callback_read_char before the signal is handled
- there's no guarantee that the signal will be processed before the
event. */
while (rl_pending_signal () != 0)
/* Do this in a while loop, in case rl_check_signals also leaves a
pending signal. I'm not sure if that's possible, but it seems
better to handle the scenario than to assert. */
rl_check_signals ();
#elif RL_VERSION_MAJOR == 7
/* Unfortunately, rl_check_signals is not available. Use private
function _rl_signal_handler instead. */
while (rl_pending_signal () != 0)
_rl_signal_handler (rl_pending_signal ());
#else
#error "Readline major version >= 7 expected"
#endif
if (after_char_processing_hook)
(*after_char_processing_hook) ();
}
CATCH_SJLJ (ex, RETURN_MASK_ALL)
{
gdb_expt = std::move (ex);
}
END_CATCH_SJLJ
return gdb_expt;
}
/* Wrapper around gdb_rl_callback_read_char_wrapper_sjlj to ensure
noexcept. */
static struct gdb_exception
gdb_rl_callback_read_char_wrapper_noexcept () noexcept
{
try
{
return gdb_rl_callback_read_char_wrapper_sjlj ();
}
catch (gdb_exception &ex)
{
return std::move (ex);
}
}
static void
gdb_rl_callback_read_char_wrapper (gdb_client_data client_data)
{
struct gdb_exception gdb_expt
= gdb_rl_callback_read_char_wrapper_noexcept ();
/* Rethrow using the normal EH mechanism. */
if (gdb_expt.reason < 0)
throw_exception (std::move (gdb_expt));
}
/* GDB's readline callback handler. Calls the current INPUT_HANDLER,
and propagates GDB exceptions/errors thrown from INPUT_HANDLER back
across readline. See gdb_rl_callback_read_char_wrapper. This must
be noexcept in order to avoid problems with mixing sjlj and
(sjlj-based) C++ exceptions. */
static void
gdb_rl_callback_handler (char *rl) noexcept
{
/* This is static to avoid undefined behavior when calling longjmp
-- gdb_exception has a destructor with side effects. */
static struct gdb_exception gdb_rl_expt;
struct ui *ui = current_ui;
/* In bracketed paste mode, pasting a complete line can result in a
literal newline appearing at the end of LINE. However, we never
want this in gdb. */
if (rl != nullptr)
{
size_t len = strlen (rl);
while (len > 0 && (rl[len - 1] == '\r' || rl[len - 1] == '\n'))
--len;
rl[len] = '\0';
}
try
{
/* Ensure the exception is reset on each call. */
gdb_rl_expt = {};
ui->input_handler (gdb::unique_xmalloc_ptr<char> (rl));
}
catch (gdb_exception &ex)
{
gdb_rl_expt = std::move (ex);
}
/* If we caught a GDB exception, longjmp out of the readline
callback. There's no other way for the callback to signal to
readline that an error happened. A normal return would have
readline potentially continue processing further input, redisplay
the prompt, etc. (This is what GDB historically did when it was
a C program.) Note that since we're long jumping, local variable
dtors are NOT run automatically. */
if (gdb_rl_expt.reason < 0)
throw_exception_sjlj (gdb_rl_expt);
}
/* Change the function to be invoked every time there is a character
ready on stdin. This is used when the user sets the editing off,
therefore bypassing readline, and letting gdb handle the input
itself, via gdb_readline_no_editing_callback. Also it is used in
the opposite case in which the user sets editing on again, by
restoring readline handling of the input.
NOTE: this operates on input_fd, not instream. If we are reading
commands from a file, instream will point to the file. However, we
always read commands from a file with editing off. This means that
the 'set editing on/off' will have effect only on the interactive
session. */
void
change_line_handler (int editing)
{
struct ui *ui = current_ui;
/* We can only have one instance of readline, so we only allow
editing on the main UI. */
if (ui != main_ui)
return;
/* Don't try enabling editing if the interpreter doesn't support it
(e.g., MI). */
if (!top_level_interpreter ()->supports_command_editing ()
|| !command_interp ()->supports_command_editing ())
return;
if (editing)
{
gdb_assert (ui == main_ui);
/* Turn on editing by using readline. */
ui->call_readline = gdb_rl_callback_read_char_wrapper;
}
else
{
/* Turn off editing by using gdb_readline_no_editing_callback. */
if (ui->command_editing)
gdb_rl_callback_handler_remove ();
ui->call_readline = gdb_readline_no_editing_callback;
}
ui->command_editing = editing;
}
/* The functions below are wrappers for rl_callback_handler_remove and
rl_callback_handler_install that keep track of whether the callback
handler is installed in readline. This is necessary because after
handling a target event of a background execution command, we may
need to reinstall the callback handler if it was removed due to a
secondary prompt. See gdb_readline_wrapper_line. We don't
unconditionally install the handler for every target event because
that also clears the line buffer, thus installing it while the user
is typing would lose input. */
/* Whether we've registered a callback handler with readline. */
static bool callback_handler_installed;
/* See event-top.h, and above. */
void
gdb_rl_callback_handler_remove (void)
{
gdb_assert (current_ui == main_ui);
rl_callback_handler_remove ();
callback_handler_installed = false;
}
/* See event-top.h, and above. Note this wrapper doesn't have an
actual callback parameter because we always install
INPUT_HANDLER. */
void
gdb_rl_callback_handler_install (const char *prompt)
{
gdb_assert (current_ui == main_ui);
/* Calling rl_callback_handler_install resets readline's input
buffer. Calling this when we were already processing input
therefore loses input. */
gdb_assert (!callback_handler_installed);
#ifdef RL_STATE_EOF
/* Some versions of readline contain a bug where the rl_eof_found flag
would not be reset back to 0 in rl_initialize, despite the
RL_STATE_EOF flag being cleared in this function.
The consequence of this mistake is that readline will appear to get
stuck in the EOF state, and will emit an extra '\n' character each
time an input line is completed.
Work around this by clearing the EOF state now ourselves. */
if (RL_ISSTATE (RL_STATE_EOF))
{
RL_UNSETSTATE (RL_STATE_EOF);
rl_eof_found = 0;
}
#endif /* RL_STATE_EOF */
rl_callback_handler_install (prompt, gdb_rl_callback_handler);
callback_handler_installed = true;
}
/* See event-top.h, and above. */
void
gdb_rl_callback_handler_reinstall (void)
{
gdb_assert (current_ui == main_ui);
if (!callback_handler_installed)
{
/* Passing NULL as prompt argument tells readline to not display
a prompt. */
gdb_rl_callback_handler_install (NULL);
}
}
/* Displays the prompt. If the argument NEW_PROMPT is NULL, the
prompt that is displayed is the current top level prompt.
Otherwise, it displays whatever NEW_PROMPT is as a local/secondary
prompt.
This is used after each gdb command has completed, and in the
following cases:
1. When the user enters a command line which is ended by '\'
indicating that the command will continue on the next line. In
that case the prompt that is displayed is the empty string.
2. When the user is entering 'commands' for a breakpoint, or
actions for a tracepoint. In this case the prompt will be '>'
3. On prompting for pagination. */
void
display_gdb_prompt (const char *new_prompt)
{
std::string actual_gdb_prompt;
annotate_display_prompt ();
/* Reset the nesting depth used when trace-commands is set. */
reset_command_nest_depth ();
/* Do not call the python hook on an explicit prompt change as
passed to this function, as this forms a secondary/local prompt,
IE, displayed but not set. */
if (! new_prompt)
{
struct ui *ui = current_ui;
if (ui->prompt_state == PROMPTED)
internal_error (_("double prompt"));
else if (ui->prompt_state == PROMPT_BLOCKED)
{
/* This is to trick readline into not trying to display the
prompt. Even though we display the prompt using this
function, readline still tries to do its own display if
we don't call rl_callback_handler_install and
rl_callback_handler_remove (which readline detects
because a global variable is not set). If readline did
that, it could mess up gdb signal handlers for SIGINT.
Readline assumes that between calls to rl_set_signals and
rl_clear_signals gdb doesn't do anything with the signal
handlers. Well, that's not the case, because when the
target executes we change the SIGINT signal handler. If
we allowed readline to display the prompt, the signal
handler change would happen exactly between the calls to
the above two functions. Calling
rl_callback_handler_remove(), does the job. */
if (current_ui->command_editing)
gdb_rl_callback_handler_remove ();
return;
}
else if (ui->prompt_state == PROMPT_NEEDED)
{
/* Display the top level prompt. */
actual_gdb_prompt = top_level_prompt ();
ui->prompt_state = PROMPTED;
}
}
else
actual_gdb_prompt = new_prompt;
if (current_ui->command_editing)
{
gdb_rl_callback_handler_remove ();
gdb_rl_callback_handler_install (actual_gdb_prompt.c_str ());
}
/* new_prompt at this point can be the top of the stack or the one
passed in. It can't be NULL. */
else
{
/* Don't use a _filtered function here. It causes the assumed
character position to be off, since the newline we read from
the user is not accounted for. */
printf_unfiltered ("%s", actual_gdb_prompt.c_str ());
gdb_flush (gdb_stdout);
}
}
/* Notify the 'before_prompt' observer, and run any additional actions
that must be done before we display the prompt. */
static void
notify_before_prompt (const char *prompt)
{
/* Give observers a chance of changing the prompt. E.g., the python
`gdb.prompt_hook' is installed as an observer. */
gdb::observers::before_prompt.notify (prompt);
/* As we are about to display the prompt, and so GDB might be sitting
idle for some time, close all the cached BFDs. This ensures that
when we next start running a user command all BFDs will be reopened
as needed, and as a result, we will see any on-disk changes. */
bfd_cache_close_all ();
}
/* Return the top level prompt, as specified by "set prompt", possibly
overridden by the python gdb.prompt_hook hook, and then composed
with the prompt prefix and suffix (annotations). */
static std::string
top_level_prompt (void)
{
notify_before_prompt (get_prompt ().c_str ());
const std::string &prompt = get_prompt ();
if (annotation_level >= 2)
{
/* Prefix needs to have new line at end. */
const char prefix[] = "\n\032\032pre-prompt\n";
/* Suffix needs to have a new line at end and \032 \032 at
beginning. */
const char suffix[] = "\n\032\032prompt\n";
return std::string (prefix) + prompt.c_str () + suffix;
}
return prompt;
}
/* Get a reference to the current UI's line buffer. This is used to
construct a whole line of input from partial input. */
static std::string &
get_command_line_buffer (void)
{
return current_ui->line_buffer;
}
/* Re-enable stdin after the end of an execution command in
synchronous mode, or after an error from the target, and we aborted
the exec operation. */
void
async_enable_stdin (void)
{
struct ui *ui = current_ui;
if (ui->prompt_state == PROMPT_BLOCKED
&& !ui->keep_prompt_blocked)
{
target_terminal::ours ();
ui->register_file_handler ();
ui->prompt_state = PROMPT_NEEDED;
}
}
/* Disable reads from stdin (the console) marking the command as
synchronous. */
void
async_disable_stdin (void)
{
struct ui *ui = current_ui;
ui->prompt_state = PROMPT_BLOCKED;
ui->unregister_file_handler ();
}
/* Handle a gdb command line. This function is called when
handle_line_of_input has concatenated one or more input lines into
a whole command. */
void
command_handler (const char *command)
{
struct ui *ui = current_ui;
const char *c;
if (ui->instream == ui->stdin_stream)
reinitialize_more_filter ();
scoped_command_stats stat_reporter (true);
/* Do not execute commented lines. */
for (c = command; *c == ' ' || *c == '\t'; c++)
;
if (c[0] != '#')
{
execute_command (command, ui->instream == ui->stdin_stream);
/* Do any commands attached to breakpoint we stopped at. */
bpstat_do_actions ();
}
}
/* Append RL, an input line returned by readline or one of its emulations, to
CMD_LINE_BUFFER. Return true if we have a whole command line ready to be
processed by the command interpreter or false if the command line isn't
complete yet (input line ends in a backslash). */
static bool
command_line_append_input_line (std::string &cmd_line_buffer, const char *rl)
{
size_t len = strlen (rl);
if (len > 0 && rl[len - 1] == '\\')
{
/* Don't copy the backslash and wait for more. */
cmd_line_buffer.append (rl, len - 1);
return false;
}
else
{
/* Copy whole line including terminating null, and we're
done. */
cmd_line_buffer.append (rl, len + 1);
return true;
}
}
/* Handle a line of input coming from readline.
If the read line ends with a continuation character (backslash), return
nullptr. Otherwise, return a pointer to the command line, indicating a whole
command line is ready to be executed.
The returned pointer may or may not point to CMD_LINE_BUFFER's internal
buffer.
Return EOF on end of file.
If REPEAT, handle command repetitions:
- If the input command line is NOT empty, the command returned is
saved using save_command_line () so that it can be repeated later.
- OTOH, if the input command line IS empty, return the saved
command instead of the empty input line.
*/
const char *
handle_line_of_input (std::string &cmd_line_buffer,
const char *rl, int repeat,
const char *annotation_suffix)
{
struct ui *ui = current_ui;
int from_tty = ui->instream == ui->stdin_stream;
if (rl == NULL)
return (char *) EOF;
bool complete = command_line_append_input_line (cmd_line_buffer, rl);
if (!complete)
return NULL;
if (from_tty && annotation_level > 1)
printf_unfiltered (("\n\032\032post-%s\n"), annotation_suffix);
#define SERVER_COMMAND_PREFIX "server "
server_command = startswith (cmd_line_buffer.c_str (), SERVER_COMMAND_PREFIX);
if (server_command)
{
/* Note that we don't call `save_command_line'. Between this
and the check in dont_repeat, this insures that repeating
will still do the right thing. */
return cmd_line_buffer.c_str () + strlen (SERVER_COMMAND_PREFIX);
}
/* Do history expansion if that is wished. */
if (history_expansion_p && from_tty && current_ui->input_interactive_p ())
{
char *cmd_expansion;
int expanded;
/* Note: here, we pass a pointer to the std::string's internal buffer as
a `char *`. At the time of writing, readline's history_expand does
not modify the passed-in string. Ideally, readline should be modified
to make that parameter `const char *`. */
expanded = history_expand (&cmd_line_buffer[0], &cmd_expansion);
gdb::unique_xmalloc_ptr<char> history_value (cmd_expansion);
if (expanded)
{
/* Print the changes. */
printf_unfiltered ("%s\n", history_value.get ());
/* If there was an error, call this function again. */
if (expanded < 0)
return cmd_line_buffer.c_str ();
cmd_line_buffer = history_value.get ();
}
}
/* If we just got an empty line, and that is supposed to repeat the
previous command, return the previously saved command. */
const char *p1;
for (p1 = cmd_line_buffer.c_str (); *p1 == ' ' || *p1 == '\t'; p1++)
;
if (repeat && *p1 == '\0')
return get_saved_command_line ();
/* Add command to history if appropriate. Note: lines consisting
solely of comments are also added to the command history. This
is useful when you type a command, and then realize you don't
want to execute it quite yet. You can comment out the command
and then later fetch it from the value history and remove the
'#'. The kill ring is probably better, but some people are in
the habit of commenting things out. */
if (cmd_line_buffer[0] != '\0' && from_tty && current_ui->input_interactive_p ())
gdb_add_history (cmd_line_buffer.c_str ());
/* Save into global buffer if appropriate. */
if (repeat)
{
save_command_line (cmd_line_buffer.c_str ());
/* It is important that we return a pointer to the saved command line
here, for the `cmd_start == saved_command_line` check in
execute_command to work. */
return get_saved_command_line ();
}
return cmd_line_buffer.c_str ();
}
/* See event-top.h. */
void
gdb_rl_deprep_term_function (void)
{
#ifdef RL_STATE_EOF
std::optional<scoped_restore_tmpl<int>> restore_eof_found;
if (RL_ISSTATE (RL_STATE_EOF))
{
printf_unfiltered ("quit\n");
restore_eof_found.emplace (&rl_eof_found, 0);
}
#endif /* RL_STATE_EOF */
rl_deprep_terminal ();
}
/* Handle a complete line of input. This is called by the callback
mechanism within the readline library. Deal with incomplete
commands as well, by saving the partial input in a global
buffer.
NOTE: This is the asynchronous version of the command_line_input
function. */
void
command_line_handler (gdb::unique_xmalloc_ptr<char> &&rl)
{
std::string &line_buffer = get_command_line_buffer ();
struct ui *ui = current_ui;
const char *cmd = handle_line_of_input (line_buffer, rl.get (), 1, "prompt");
if (cmd == (char *) EOF)
{
/* stdin closed. The connection with the terminal is gone.
This happens at the end of a testsuite run, after Expect has
hung up but GDB is still alive. In such a case, we just quit
gdb killing the inferior program too. This also happens if the
user sends EOF, which is usually bound to ctrl+d. */
#ifndef RL_STATE_EOF
/* When readline is using bracketed paste mode, then, when eof is
received, readline will emit the control sequence to leave
bracketed paste mode.
This control sequence ends with \r, which means that the "quit" we
are about to print will overwrite the prompt on this line.
The solution to this problem is to actually print the "quit"
message from gdb_rl_deprep_term_function (see above), however, we
can only do that if we can know, in that function, when eof was
received.
Unfortunately, with older versions of readline, it is not possible
in the gdb_rl_deprep_term_function to know if eof was received or
not, and, as GDB can be built against the system readline, which
could be older than the readline in GDB's repository, then we
can't be sure that we can work around this prompt corruption in
the gdb_rl_deprep_term_function function.
If we get here, RL_STATE_EOF is not defined. This indicates that
we are using an older readline, and couldn't print the quit
message in gdb_rl_deprep_term_function. So, what we do here is
check to see if bracketed paste mode is on or not. If it's on
then we print a \n and then the quit, this means the user will
see:
(gdb)
quit
Rather than the usual:
(gdb) quit
Which we will get with a newer readline, but this really is the
best we can do with older versions of readline. */
const char *value = rl_variable_value ("enable-bracketed-paste");
if (value != nullptr && strcmp (value, "on") == 0
&& ((rl_readline_version >> 8) & 0xff) > 0x07)
printf_unfiltered ("\n");
printf_unfiltered ("quit\n");
#endif
execute_command ("quit", 1);
}
else if (cmd == NULL)
{
/* We don't have a full line yet. Print an empty prompt. */
display_gdb_prompt ("");
}
else
{
ui->prompt_state = PROMPT_NEEDED;
/* Ensure the UI's line buffer is empty for the next command. */
SCOPE_EXIT { line_buffer.clear (); };
command_handler (cmd);
if (ui->prompt_state != PROMPTED)
display_gdb_prompt (0);
}
}
/* Does reading of input from terminal w/o the editing features
provided by the readline library. Calls the line input handler
once we have a whole input line. */
void
gdb_readline_no_editing_callback (gdb_client_data client_data)
{
int c;
std::string line_buffer;
struct ui *ui = current_ui;
FILE *stream = ui->instream != nullptr ? ui->instream : ui->stdin_stream;
gdb_assert (stream != nullptr);
/* We still need the while loop here, even though it would seem
obvious to invoke gdb_readline_no_editing_callback at every
character entered. If not using the readline library, the
terminal is in cooked mode, which sends the characters all at
once. Poll will notice that the input fd has changed state only
after enter is pressed. At this point we still need to fetch all
the chars entered. */
while (1)
{
/* Read from stdin if we are executing a user defined command.
This is the right thing for prompt_for_continue, at least. */
c = fgetc (stream);
if (c == EOF)
{
if (!line_buffer.empty ())
{
/* The last line does not end with a newline. Return it, and
if we are called again fgetc will still return EOF and
we'll return NULL then. */
break;
}
ui->input_handler (NULL);
return;
}
if (c == '\n')
{
if (!line_buffer.empty () && line_buffer.back () == '\r')
line_buffer.pop_back ();
break;
}
line_buffer += c;
}
ui->input_handler (make_unique_xstrdup (line_buffer.c_str ()));
}
/* Attempt to unblock signal SIG, return true if the signal was unblocked,
otherwise, return false. */
static bool
unblock_signal (int sig)
{
#if HAVE_SIGPROCMASK
sigset_t sigset;
sigemptyset (&sigset);
sigaddset (&sigset, sig);
gdb_sigmask (SIG_UNBLOCK, &sigset, 0);
return true;
#endif
return false;
}
/* Signal safe language specific strings. */
#ifdef GDB_PRINT_INTERNAL_BACKTRACE
static const char *str_fatal_signal;
static const char *str_sigsegv;
#ifdef SIGFPE
static const char *str_sigfpe;
#endif
#ifdef SIGBUS
static const char *str_sigbus;
#endif
#ifdef SIGABRT
static const char *str_sigabrt;
#endif
static const char *str_unknown_signal;
static const char *str_fatal_error_detected_gdb_will_now_terminate;
static const char *str_this_is_a_bug;
static const char *str_for_instructions_see;
/* Initialize language specific strings. */
static void
init_str_handle_fatal_signal ()
{
str_fatal_signal = _("Fatal signal: ");
str_sigsegv = strsignal (SIGSEGV);
#ifdef SIGFPE
str_sigfpe = strsignal (SIGFPE);
#endif
#ifdef SIGBUS
str_sigbus = strsignal (SIGBUS);
#endif
#ifdef SIGABRT
str_sigabrt = strsignal (SIGABRT);
#endif
str_unknown_signal = _("Unknown signal");
str_fatal_error_detected_gdb_will_now_terminate =
_("A fatal error internal to GDB has been detected, "
"further\ndebugging is not possible. GDB will now "
"terminate.\n\n");
str_this_is_a_bug = _("This is a bug, please report it.");
str_for_instructions_see = _(" For instructions, see:\n");
}
#endif
/* Called to handle fatal signals. SIG is the signal number. */
[[noreturn]] static void
handle_fatal_signal (int sig)
{
#ifdef TUI
tui_disable ();
#endif
#ifdef GDB_PRINT_INTERNAL_BACKTRACE
const auto sig_write = [] (const char *msg) -> void
{
gdb_stderr->write_async_safe (msg, strlen (msg));
};
if (bt_on_fatal_signal)
{
sig_write ("\n\n");
sig_write (str_fatal_signal);
switch (sig)
{
case SIGSEGV:
sig_write (str_sigsegv);
break;
#ifdef SIGFPE
case SIGFPE:
sig_write (str_sigfpe);
break;