/usr/src/gnu/usr.bin/binutils/gdb/event-top.c

Bug Summary

File:	src/gnu/usr.bin/binutils/gdb/event-top.c
Warning:	line 675, column 10 Dereference of null pointer (loaded from variable 'p1')
Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name event-top.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/binutils/obj/gdb -resource-dir /usr/local/lib/clang/13.0.0 -D PIE_DEFAULT=1 -I . -I /usr/src/gnu/usr.bin/binutils/gdb -I /usr/src/gnu/usr.bin/binutils/gdb/config -D LOCALEDIR="/usr/share/locale" -D HAVE_CONFIG_H -I /usr/src/gnu/usr.bin/binutils/gdb/../include/opcode -I ../bfd -I /usr/src/gnu/usr.bin/binutils/gdb/../bfd -I /usr/src/gnu/usr.bin/binutils/gdb/../include -I ../intl -I /usr/src/gnu/usr.bin/binutils/gdb/../intl -D MI_OUT=1 -D TUI=1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/gnu/usr.bin/binutils/obj/gdb -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -fcommon -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/gnu/usr.bin/binutils/gdb/event-top.c
1/* Top level stuff for GDB, the GNU debugger.
 Copyright 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
 Written by Elena Zannoni <ezannoni@cygnus.com> 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 2 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, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330,
 Boston, MA 02111-1307, USA. */

22#include "defs.h"
23#include "top.h"
24#include "inferior.h"
25#include "target.h"
26#include "terminal.h"		/* for job_control */
27#include "event-loop.h"
28#include "event-top.h"
29#include "interps.h"
30#include <signal.h>

32/* For dont_repeat() */
33#include "gdbcmd.h"

35/* readline include files */
36#include "readline/readline.h"
37#include "readline/history.h"

39/* readline defines this.  */
40#undef savestring

42static void rl_callback_read_char_wrapper (gdb_client_data client_data);
43static void command_line_handler (char *rl);
44static void command_line_handler_continuation (struct continuation_arg *arg);
45static void change_line_handler (void);
46static void change_annotation_level (void);
47static void command_handler (char *command);
48static void async_do_nothing (gdb_client_data arg);
49static void async_disconnect (gdb_client_data arg);
50static void async_stop_sig (gdb_client_data arg);
51static void async_float_handler (gdb_client_data arg);

53/* Signal handlers. */
54static void handle_sigquit (int sig);
55static void handle_sighup (int sig);
56static void handle_sigfpe (int sig);
57#if defined(SIGWINCH28) && defined(SIGWINCH_HANDLER)
58static void handle_sigwinch (int sig);
59#endif

61/* Functions to be invoked by the event loop in response to
 signals. */
63static void async_do_nothing (gdb_client_data);
64static void async_disconnect (gdb_client_data);
65static void async_float_handler (gdb_client_data);
66static void async_stop_sig (gdb_client_data);

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

88void (*input_handler) (char *);
89void (*call_readline) (gdb_client_data);

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

93/* 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. */
99int async_command_editing_p;

101/* This variable contains the new prompt that the user sets with the
 set prompt command. */
103char *new_async_prompt;

105/* This is the annotation suffix that will be used when the
 annotation_level is 2. */
107char *async_annotation_suffix;

109/* This is used to display the notification of the completion of an
 asynchronous execution command. */
111int exec_done_display_p = 0;

113/* This is the file descriptor for the input stream that GDB uses to
 read commands from. */
115int input_fd;

117/* This is the prompt stack. Prompts will be pushed on the stack as
 needed by the different 'kinds' of user inputs GDB is asking
 for. See event-loop.h. */
120struct prompts the_prompts;

122/* signal handling variables */
123/* 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. */
128void *sigint_token;
129#ifdef SIGHUP1
130void *sighup_token;
131#endif
132void *sigquit_token;
133void *sigfpe_token;
134#if defined(SIGWINCH28) && defined(SIGWINCH_HANDLER)
135void *sigwinch_token;
136#endif
137#ifdef STOP_SIGNAL18
138void *sigtstp_token;
139#endif

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

148struct readline_input_state
{
  char *linebuffer;
  char *linebuffer_ptr;
}
153readline_input_state;

155/* This hook is called by rl_callback_read_char_wrapper after each
 character is processed.  */
157void (*after_char_processing_hook) ();
158

160/* Wrapper function for calling into the readline library. The event
 loop expects the callback function to have a paramter, while readline 
 expects none. */
163static void
164rl_callback_read_char_wrapper (gdb_client_data client_data)
165{
rl_callback_read_char ();
if (after_char_processing_hook)
  (*after_char_processing_hook) ();
169}

171/* Initialize all the necessary variables, start the event loop,
 register readline, and stdin, start the loop. */
173void
174cli_command_loop (void)
175{
int length;
char *a_prompt;
char *gdb_prompt = get_prompt ();

/* If we are using readline, set things up and display the first
   prompt, otherwise just print the prompt. */
if (async_command_editing_p)
  {
    /* Tell readline what the prompt to display is and what function it
       will need to call after a whole line is read. This also displays
       the first prompt. */
    length = strlen (PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix) + strlen (gdb_prompt) + strlen (SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix) + 1;
    a_prompt = (char *) xmalloc (length);
    strcpy (a_prompt, PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix);
    strcat (a_prompt, gdb_prompt);
    strcat (a_prompt, SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix);
    rl_callback_handler_install (a_prompt, input_handler);
  }
else
  display_gdb_prompt (0);

/* Now it's time to start the event loop. */
start_event_loop ();
199}

201/* 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_readline2. Also it is used in the opposite case in
 which the user sets editing on again, by restoring readline
 handling of the input. */
207static void
208change_line_handler (void)
209{
/* NOTE: this operates on input_fd, not instream. If we are reading
   commands from a file, instream will point to the file. However in
   async mode, 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. */

if (async_command_editing_p)
  {
    /* Turn on editing by using readline. */
    call_readline = rl_callback_read_char_wrapper;
    input_handler = command_line_handler;
  }
else
  {
    /* Turn off editing by using gdb_readline2. */
    rl_callback_handler_remove ();
    call_readline = gdb_readline2;

    /* Set up the command handler as well, in case we are called as
       first thing from .gdbinit. */
    input_handler = command_line_handler;
  }
232}

234/* Displays the prompt. The prompt that is displayed is the current
 top of the prompt stack, if the argument NEW_PROMPT is
 0. Otherwise, it displays whatever NEW_PROMPT is. 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. Other????
 FIXME: 2. & 3. not implemented yet for async. */
245void
246display_gdb_prompt (char *new_prompt)
247{
int prompt_length = 0;
char *gdb_prompt = get_prompt ();

/* Each interpreter has its own rules on displaying the command
   prompt.  */
if (!current_interp_display_prompt_p ())
  return;

if (target_executing && sync_execution)
  {
    /* 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. */

    rl_callback_handler_remove ();
    return;
  }

if (!new_prompt)
  {
    /* Just use the top of the prompt stack. */
    prompt_length = strlen (PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix) +
strlen (SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix) +
strlen (gdb_prompt) + 1;

    new_prompt = (char *) alloca (prompt_length)__builtin_alloca(prompt_length);

    /* Prefix needs to have new line at end. */
    strcpy (new_prompt, PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix);
    strcat (new_prompt, gdb_prompt);
    /* Suffix needs to have a new line at end and \032 \032 at
       beginning. */
    strcat (new_prompt, SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix);
  }

if (async_command_editing_p)
  {
    rl_callback_handler_remove ();
    rl_callback_handler_install (new_prompt, input_handler);
  }
/* new_prompt at this point can be the top of the stack or the one passed in */
else if (new_prompt)
  {
    /* 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.  */
    fputs_unfiltered (new_prompt, gdb_stdout);
    gdb_flush (gdb_stdout);
  }
308}

310/* Used when the user requests a different annotation level, with
 'set annotate'. It pushes a new prompt (with prefix and suffix) on top
 of the prompt stack, if the annotation level desired is 2, otherwise
 it pops the top of the prompt stack when we want the annotation level
 to be the normal ones (1 or 0). */
315static void
316change_annotation_level (void)
317{
char *prefix, *suffix;

if (!PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix || !PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt || !SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix)
  {
    /* The prompt stack has not been initialized to "", we are
       using gdb w/o the --async switch */
    warning ("Command has same effect as set annotate");
    return;
  }

if (annotation_level > 1)
  {
    if (!strcmp (PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix, "") && !strcmp (SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix, ""))
{
 /* Push a new prompt if the previous annotation_level was not >1. */
 prefix = (char *) alloca (strlen (async_annotation_suffix) + 10)__builtin_alloca(strlen (async_annotation_suffix) + 10);
 strcpy (prefix, "\n\032\032pre-");
 strcat (prefix, async_annotation_suffix);
 strcat (prefix, "\n");

 suffix = (char *) alloca (strlen (async_annotation_suffix) + 6)__builtin_alloca(strlen (async_annotation_suffix) + 6);
 strcpy (suffix, "\n\032\032");
 strcat (suffix, async_annotation_suffix);
 strcat (suffix, "\n");

 push_prompt (prefix, (char *) 0, suffix);
}
  }
else
  {
    if (strcmp (PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix, "") && strcmp (SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix, ""))
{
 /* Pop the top of the stack, we are going back to annotation < 1. */
 pop_prompt ();
}
  }
354}

356/* Pushes a new prompt on the prompt stack. Each prompt has three
 parts: prefix, prompt, suffix. Usually prefix and suffix are empty
 strings, except when the annotation level is 2. Memory is allocated
 within savestring for the new prompt. */
360void
361push_prompt (char *prefix, char *prompt, char *suffix)
362{
the_prompts.top++;
PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix = savestring (prefix, strlen (prefix));

/* Note that this function is used by the set annotate 2
   command. This is why we take care of saving the old prompt
   in case a new one is not specified. */
if (prompt)
  PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt = savestring (prompt, strlen (prompt));
else
  PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt = savestring (PROMPT (-1)the_prompts.prompt_stack[the_prompts.top + -1].prompt, strlen (PROMPT (-1)the_prompts.prompt_stack[the_prompts.top + -1].prompt));

SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix = savestring (suffix, strlen (suffix));
375}

377/* Pops the top of the prompt stack, and frees the memory allocated for it. */
378void
379pop_prompt (void)
380{
/* If we are not during a 'synchronous' execution command, in which
   case, the top prompt would be empty. */
if (strcmp (PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt, ""))
  /* This is for the case in which the prompt is set while the
     annotation level is 2. The top prompt will be changed, but when
     we return to annotation level < 2, we want that new prompt to be
     in effect, until the user does another 'set prompt'. */
  if (strcmp (PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt, PROMPT (-1)the_prompts.prompt_stack[the_prompts.top + -1].prompt))
    {
xfree (PROMPT (-1)the_prompts.prompt_stack[the_prompts.top + -1].prompt);
PROMPT (-1)the_prompts.prompt_stack[the_prompts.top + -1].prompt = savestring (PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt, strlen (PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt));
    }

xfree (PREFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].prefix);
xfree (PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt);
xfree (SUFFIX (0)the_prompts.prompt_stack[the_prompts.top + 0].suffix);
the_prompts.top--;
398}

400/* When there is an event ready on the stdin file desriptor, instead
 of calling readline directly throught the callback function, or
 instead of calling gdb_readline2, give gdb a chance to detect
 errors and do something. */
404void
405stdin_event_handler (int error, gdb_client_data client_data)
406{
if (error)
  {
    printf_unfiltered ("error detected on stdin\n");
    delete_file_handler (input_fd);
    discard_all_continuations ();
    /* If stdin died, we may as well kill gdb. */
    quit_command ((char *) 0, stdin(&__sF[0]) == instream);
  }
else
  (*call_readline) (client_data);
417}

419/* 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. */

423void
424async_enable_stdin (void *dummy)
425{
/* See NOTE in async_disable_stdin() */
/* FIXME: cagney/1999-09-27: Call this before clearing
   sync_execution.  Current target_terminal_ours() implementations
   check for sync_execution before switching the terminal. */
target_terminal_ours ()(*current_target.to_terminal_ours) ();
pop_prompt ();
sync_execution = 0;
433}

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

438void
439async_disable_stdin (void)
440{
sync_execution = 1;
push_prompt ("", "", "");
/* FIXME: cagney/1999-09-27: At present this call is technically
   redundant since infcmd.c and infrun.c both already call
   target_terminal_inferior().  As the terminal handling (in
   sync/async mode) is refined, the duplicate calls can be
   eliminated (Here or in infcmd.c/infrun.c). */
target_terminal_inferior ()(*current_target.to_terminal_inferior) ();
/* Add the reinstate of stdin to the list of cleanups to be done
   in case the target errors out and dies. These cleanups are also
   done in case of normal successful termination of the execution
   command, by complete_execution(). */
make_exec_error_cleanup (async_enable_stdin, NULL((void*)0));
454}
455

457/* Handles a gdb command. This function is called by
 command_line_handler, which has processed one or more input lines
 into COMMAND. */
460/* NOTE: 1999-04-30 This is the asynchronous version of the command_loop
 function.  The command_loop function will be obsolete when we
 switch to use the event loop at every execution of gdb. */
463static void
464command_handler (char *command)
465{
struct cleanup *old_chain;
int stdin_is_tty = ISATTY (stdin)(isatty ((!__isthreaded ? (((&__sF[0]))->_file) : (fileno
)((&__sF[0])))));
struct continuation_arg *arg1;
struct continuation_arg *arg2;
long time_at_cmd_start;
471#ifdef HAVE_SBRK1
long space_at_cmd_start = 0;
473#endif
extern int display_time;
extern int display_space;

quit_flag = 0;
if (instream == stdin(&__sF[0]) && stdin_is_tty)
  reinitialize_more_filter ();
old_chain = make_cleanup (null_cleanup, 0);

/* If readline returned a NULL command, it means that 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. */
if (command == 0)
  quit_command ((char *) 0, stdin(&__sF[0]) == instream);

time_at_cmd_start = get_run_time ();

if (display_space)
  {
494#ifdef HAVE_SBRK1
    char *lim = (char *) sbrk (0);
    space_at_cmd_start = lim - lim_at_start;
497#endif
  }

execute_command (command, instream == stdin(&__sF[0]));

/* Set things up for this function to be compete later, once the
   execution has completed, if we are doing an execution command,
   otherwise, just go ahead and finish. */
if (target_can_async_p ()(current_target.to_can_async_p ()) && target_executing)
  {
    arg1 =
(struct continuation_arg *) xmalloc (sizeof (struct continuation_arg));
    arg2 =
(struct continuation_arg *) xmalloc (sizeof (struct continuation_arg));
    arg1->next = arg2;
    arg2->next = NULL((void*)0);
    arg1->data.longint = time_at_cmd_start;
514#ifdef HAVE_SBRK1
    arg2->data.longint = space_at_cmd_start;
516#endif
    add_continuation (command_line_handler_continuation, arg1);
  }

/* Do any commands attached to breakpoint we stopped at. Only if we
   are always running synchronously. Or if we have just executed a
   command that doesn't start the target. */
if (!target_can_async_p ()(current_target.to_can_async_p ()) || !target_executing)
  {
    bpstat_do_actions (&stop_bpstat);
    do_cleanups (old_chain);

    if (display_time)
{
 long cmd_time = get_run_time () - time_at_cmd_start;

 printf_unfiltered ("Command execution time: %ld.%06ld\n",
	     cmd_time / 1000000, cmd_time % 1000000);
}

    if (display_space)
{
538#ifdef HAVE_SBRK1
 char *lim = (char *) sbrk (0);
 long space_now = lim - lim_at_start;
 long space_diff = space_now - space_at_cmd_start;

 printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
	     space_now,
	     (space_diff >= 0 ? '+' : '-'),
	     space_diff);
547#endif
}
  }
550}

552/* Do any commands attached to breakpoint we stopped at. Only if we
 are always running synchronously. Or if we have just executed a
 command that doesn't start the target. */
555void
556command_line_handler_continuation (struct continuation_arg *arg)
557{
extern int display_time;
extern int display_space;

long time_at_cmd_start  = arg->data.longint;
long space_at_cmd_start = arg->next->data.longint;

bpstat_do_actions (&stop_bpstat);
/*do_cleanups (old_chain); *//*?????FIXME????? */

if (display_time)
  {
    long cmd_time = get_run_time () - time_at_cmd_start;

    printf_unfiltered ("Command execution time: %ld.%06ld\n",
	 cmd_time / 1000000, cmd_time % 1000000);
  }
if (display_space)
  {
576#ifdef HAVE_SBRK1
    char *lim = (char *) sbrk (0);
    long space_now = lim - lim_at_start;
    long space_diff = space_now - space_at_cmd_start;

    printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
	 space_now,
	 (space_diff >= 0 ? '+' : '-'),
	 space_diff);
585#endif
  }
587}

589/* 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.  */

593/* NOTE: 1999-04-30 This is the asynchronous version of the
 command_line_input function. command_line_input will become
 obsolete once we use the event loop as the default mechanism in
 GDB. */
597static void
598command_line_handler (char *rl)
599{
static char *linebuffer = 0;
static unsigned linelength = 0;
char *p;
char *p1;
extern char *line;
extern int linesize;
char *nline;
char got_eof = 0;


int repeat = (instream == stdin(&__sF[0]));

if (annotation_level > 1 && instream == stdin(&__sF[0]))
1
Assuming 'annotation_level' is > 1→
2
←
Assuming the condition is false→
3
←
Taking false branch→
  {
    printf_unfiltered ("\n\032\032post-");
    puts_unfiltered (async_annotation_suffix);
    printf_unfiltered ("\n");
  }

if (linebuffer3.1
'linebuffer' is equal to null
 == 0)
4
←
Taking true branch→
  {
    linelength = 80;
    linebuffer = (char *) xmalloc (linelength);
  }

p = linebuffer;

if (more_to_come)
5
←
Assuming 'more_to_come' is 0→
6
←
Taking false branch→
  {
    strcpy (linebuffer, readline_input_state.linebuffer);
    p = readline_input_state.linebuffer_ptr;
    xfree (readline_input_state.linebuffer);
    more_to_come = 0;
    pop_prompt ();
  }

636#ifdef STOP_SIGNAL18
if (job_control)
7
←
Assuming 'job_control' is 0→
8
←
Taking false branch→
  signal (STOP_SIGNAL18, handle_stop_sig);
639#endif

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

if (source_file_name != NULL((void*)0))
9
←
Assuming 'source_file_name' is not equal to NULL→
10
←
Taking true branch→
  {
    ++source_line_number;
    sprintf (source_error,
      "%s%s:%d: Error in sourced command file:\n",
      source_pre_error,
      source_file_name,
      source_line_number);
    error_pre_print = source_error;
  }

/* If we are in this case, then command_handler will call quit 
   and exit from gdb. */
if (!rl || rl == (char *) EOF(-1))
11
←
Assuming 'rl' is non-null→
12
←
Assuming the condition is true→
13
←
Taking true branch→
  {
    got_eof = 1;
    command_handler (0);
  }
if (strlen (rl) + 1 + (p - linebuffer) > linelength)
14
←
Assuming the condition is false→
15
←
Taking false branch→
  {
    linelength = strlen (rl) + 1 + (p - linebuffer);
    nline = (char *) xrealloc (linebuffer, linelength);
    p += nline - linebuffer;
    linebuffer = nline;
  }
p1 = rl;
/* Copy line.  Don't copy null at end.  (Leaves line alone
   if this was just a newline)  */
while (*p1)
16
←
Loop condition is true.  Entering loop body→
18
←
Dereference of null pointer (loaded from variable 'p1')
  *p++ = *p1++;
17
←
Null pointer value stored to 'p1'→

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

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

    readline_input_state.linebuffer = savestring (linebuffer,
				    strlen (linebuffer));
    readline_input_state.linebuffer_ptr = p;

    /* We will not invoke a execute_command if there is more
input expected to complete the command. So, we need to
print an empty prompt here. */
    more_to_come = 1;
    push_prompt ("", "", "");
    display_gdb_prompt (0);
    return;
  }

697#ifdef STOP_SIGNAL18
if (job_control)
  signal (STOP_SIGNAL18, SIG_DFL(void (*)(int))0);
700#endif

702#define SERVER_COMMAND_LENGTH7 7
server_command =
  (p - linebuffer > SERVER_COMMAND_LENGTH7)
  && strncmp (linebuffer, "server ", SERVER_COMMAND_LENGTH7) == 0;
if (server_command)
  {
    /* Note that we don't set `line'.  Between this and the check in
       dont_repeat, this insures that repeating will still do the
       right thing.  */
    *p = '\0';
    command_handler (linebuffer + SERVER_COMMAND_LENGTH7);
    display_gdb_prompt (0);
    return;
  }

/* Do history expansion if that is wished.  */
if (history_expansion_p && instream == stdin(&__sF[0])
    && ISATTY (instream)(isatty ((!__isthreaded ? ((instream)->_file) : (fileno)(instream
)))))
  {
    char *history_value;
    int expanded;

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

 /* If there was an error, call this function again.  */
 if (expanded < 0)
   {
     xfree (history_value);
     return;
   }
 if (strlen (history_value) > linelength)
   {
     linelength = strlen (history_value) + 1;
     linebuffer = (char *) xrealloc (linebuffer, linelength);
   }
 strcpy (linebuffer, history_value);
 p = linebuffer + strlen (linebuffer);
 xfree (history_value);
}
  }

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

for (p1 = linebuffer; *p1 == ' ' || *p1 == '\t'; p1++);
if (repeat && !*p1)
  {
    command_handler (line);
    display_gdb_prompt (0);
    return;
  }

*p = 0;

/* Add line to history if appropriate.  */
if (instream == stdin(&__sF[0])
    && ISATTY (stdin)(isatty ((!__isthreaded ? (((&__sF[0]))->_file) : (fileno
)((&__sF[0]))))) && *linebuffer)
  add_history (linebuffer);

/* Note: lines consisting solely of comments are 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 (*p1 == '#')
  *p1 = '\0';			/* Found a comment. */

/* Save into global buffer if appropriate.  */
if (repeat)
  {
    if (linelength > linesize)
{
 line = xrealloc (line, linelength);
 linesize = linelength;
}
    strcpy (line, linebuffer);
    if (!more_to_come)
{
 command_handler (line);
 display_gdb_prompt (0);
}
    return;
  }

command_handler (linebuffer);
display_gdb_prompt (0);
return;
802}

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

807/* NOTE: 1999-04-30 Asynchronous version of gdb_readline. gdb_readline
 will become obsolete when the event loop is made the default
 execution for gdb. */
810void
811gdb_readline2 (gdb_client_data client_data)
812{
int c;
char *result;
int input_index = 0;
int result_size = 80;
static int done_once = 0;

/* Unbuffer the input stream, so that, later on, the calls to fgetc
   fetch only one char at the time from the stream. The fgetc's will
   get up to the first newline, but there may be more chars in the
   stream after '\n'. If we buffer the input and fgetc drains the
   stream, getting stuff beyond the newline as well, a select, done
   afterwards will not trigger. */
if (!done_once && !ISATTY (instream)(isatty ((!__isthreaded ? ((instream)->_file) : (fileno)(instream
)))))
  {
    setbuf (instream, NULL((void*)0));
    done_once = 1;
  }

result = (char *) xmalloc (result_size);

/* We still need the while loop here, even though it would seem
   obvious to invoke gdb_readline2 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 (instream ? instream : stdin(&__sF[0]));

    if (c == EOF(-1))
{
 if (input_index > 0)
   /* 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;
 xfree (result);
 (*input_handler) (0);
}

    if (c == '\n')
{
 if (input_index > 0 && result[input_index - 1] == '\r')
   input_index--;
 break;
}

    result[input_index++] = c;
    while (input_index >= result_size)
{
 result_size *= 2;
 result = (char *) xrealloc (result, result_size);
}
  }

result[input_index++] = '\0';
(*input_handler) (result);
874}
875

877/* Initialization of signal handlers and tokens.  There is a function
 handle_sig* for each of the signals GDB cares about. Specifically:
 SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH.  These
 functions are the actual signal handlers associated to the signals
 via calls to signal().  The only job for these functions is to
 enqueue the appropriate event/procedure with the event loop.  Such
 procedures are the old signal handlers. The event loop will take
 care of invoking the queued procedures to perform the usual tasks
 associated with the reception of the signal. */
886/* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
 init_signals will become obsolete as we move to have to event loop
 as the default for gdb. */
889void
890async_init_signals (void)
891{
signal (SIGINT2, handle_sigint);
sigint_token =
  create_async_signal_handler (async_request_quit, NULL((void*)0));

/* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
   to the inferior and breakpoints will be ignored.  */
898#ifdef SIGTRAP5
signal (SIGTRAP5, SIG_DFL(void (*)(int))0);
900#endif

/* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
   passed to the inferior, which we don't want.  It would be
   possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
   on BSD4.3 systems using vfork, that can affect the
   GDB process as well as the inferior (the signal handling tables
   might be in memory, shared between the two).  Since we establish
   a handler for SIGQUIT, when we call exec it will set the signal
   to SIG_DFL for us.  */
signal (SIGQUIT3, handle_sigquit);
sigquit_token =
  create_async_signal_handler (async_do_nothing, NULL((void*)0));
913#ifdef SIGHUP1
if (signal (SIGHUP1, handle_sighup) != SIG_IGN(void (*)(int))1)
  sighup_token =
    create_async_signal_handler (async_disconnect, NULL((void*)0));
else
  sighup_token =
    create_async_signal_handler (async_do_nothing, NULL((void*)0));
920#endif
signal (SIGFPE8, handle_sigfpe);
sigfpe_token =
  create_async_signal_handler (async_float_handler, NULL((void*)0));

925#if defined(SIGWINCH28) && defined(SIGWINCH_HANDLER)
signal (SIGWINCH28, handle_sigwinch);
sigwinch_token =
  create_async_signal_handler (SIGWINCH_HANDLER, NULL((void*)0));
929#endif
930#ifdef STOP_SIGNAL18
sigtstp_token =
  create_async_signal_handler (async_stop_sig, NULL((void*)0));
933#endif

935}

937void
938mark_async_signal_handler_wrapper (void *token)
939{
mark_async_signal_handler ((struct async_signal_handler *) token);
941}

943/* Tell the event loop what to do if SIGINT is received. 
 See event-signal.c. */
945void
946handle_sigint (int sig)
947{
signal (sig, handle_sigint);

/* If immediate_quit is set, we go ahead and process the SIGINT right
   away, even if we usually would defer this to the event loop. The
   assumption here is that it is safe to process ^C immediately if
   immediate_quit is set. If we didn't, SIGINT would be really
   processed only the next time through the event loop.  To get to
   that point, though, the command that we want to interrupt needs to
   finish first, which is unacceptable. */
if (immediate_quit)
  async_request_quit (0);
else
  /* If immediate quit is not set, we process SIGINT the next time
     through the loop, which is fine. */
  mark_async_signal_handler_wrapper (sigint_token);
963}

965/* Do the quit. All the checks have been done by the caller. */
966void
967async_request_quit (gdb_client_data arg)
968{
quit_flag = 1;
quit ();
971}

973/* Tell the event loop what to do if SIGQUIT is received. 
 See event-signal.c. */
975static void
976handle_sigquit (int sig)
977{
mark_async_signal_handler_wrapper (sigquit_token);
signal (sig, handle_sigquit);
980}

982/* Called by the event loop in response to a SIGQUIT. */
983static void
984async_do_nothing (gdb_client_data arg)
985{
/* Empty function body. */
987}

989#ifdef SIGHUP1
990/* Tell the event loop what to do if SIGHUP is received. 
 See event-signal.c. */
992static void
993handle_sighup (int sig)
994{
mark_async_signal_handler_wrapper (sighup_token);
signal (sig, handle_sighup);
997}

999/* Called by the event loop to process a SIGHUP */
1000static void
1001async_disconnect (gdb_client_data arg)
1002{
catch_errors (quit_cover, NULL((void*)0),
"Could not kill the program being debugged",
RETURN_MASK_ALL((1 << (int)(-RETURN_QUIT)) | (1 << (int)(-RETURN_ERROR
))));
signal (SIGHUP1, SIG_DFL(void (*)(int))0);	/*FIXME: ??????????? */
kill (getpid (), SIGHUP1);
1008}
1009#endif

1011#ifdef STOP_SIGNAL18
1012void
1013handle_stop_sig (int sig)
1014{
mark_async_signal_handler_wrapper (sigtstp_token);
signal (sig, handle_stop_sig);
1017}

1019static void
1020async_stop_sig (gdb_client_data arg)
1021{
char *prompt = get_prompt ();
1023#if STOP_SIGNAL18 == SIGTSTP18
signal (SIGTSTP18, SIG_DFL(void (*)(int))0);
1025#if HAVE_SIGPROCMASK1
{
  sigset_t zero;

  sigemptyset (&zero);
  sigprocmask (SIG_SETMASK3, &zero, 0);
}
1032#elif HAVE_SIGSETMASK1
sigsetmask (0);
1034#endif
kill (getpid (), SIGTSTP18);
signal (SIGTSTP18, handle_stop_sig);
1037#else
signal (STOP_SIGNAL18, handle_stop_sig);
1039#endif
printf_unfiltered ("%s", prompt);
gdb_flush (gdb_stdout);

/* Forget about any previous command -- null line now will do nothing.  */
dont_repeat ();
1045}
1046#endif /* STOP_SIGNAL */

1048/* Tell the event loop what to do if SIGFPE is received. 
 See event-signal.c. */
1050static void
1051handle_sigfpe (int sig)
1052{
mark_async_signal_handler_wrapper (sigfpe_token);
signal (sig, handle_sigfpe);
1055}

1057/* Event loop will call this functin to process a SIGFPE. */
1058static void
1059async_float_handler (gdb_client_data arg)
1060{
/* This message is based on ANSI C, section 4.7. Note that integer
   divide by zero causes this, so "float" is a misnomer. */
error ("Erroneous arithmetic operation.");
1064}

1066/* Tell the event loop what to do if SIGWINCH is received. 
 See event-signal.c. */
1068#if defined(SIGWINCH28) && defined(SIGWINCH_HANDLER)
1069static void
1070handle_sigwinch (int sig)
1071{
mark_async_signal_handler_wrapper (sigwinch_token);
signal (sig, handle_sigwinch);
1074}
1075#endif
1076

1078/* Called by do_setshow_command.  */
1079void
1080set_async_editing_command (char *args, int from_tty, struct cmd_list_element *c)
1081{
change_line_handler ();
1083}

1085/* Called by do_setshow_command.  */
1086void
1087set_async_annotation_level (char *args, int from_tty, struct cmd_list_element *c)
1088{
change_annotation_level ();
1090}

1092/* Called by do_setshow_command.  */
1093void
1094set_async_prompt (char *args, int from_tty, struct cmd_list_element *c)
1095{
PROMPT (0)the_prompts.prompt_stack[the_prompts.top + 0].prompt = savestring (new_async_prompt, strlen (new_async_prompt));
1097}

1099/* Set things up for readline to be invoked via the alternate
 interface, i.e. via a callback function (rl_callback_read_char),
 and hook up instream to the event loop. */
1102void
1103gdb_setup_readline (void)
1104{
/* This function is a noop for the sync case.  The assumption is
   that the sync setup is ALL done in gdb_init, and we would only
   mess it up here.  The sync stuff should really go away over
   time.  */

gdb_stdout = stdio_fileopen (stdout(&__sF[1]));
gdb_stderr = stdio_fileopen (stderr(&__sF[2]));
gdb_stdlog = gdb_stderr;  /* for moment */
gdb_stdtarg = gdb_stderr; /* for moment */

/* If the input stream is connected to a terminal, turn on
   editing.  */
if (ISATTY (instream)(isatty ((!__isthreaded ? ((instream)->_file) : (fileno)(instream
)))))
  {
    /* Tell gdb that we will be using the readline library. This
could be overwritten by a command in .gdbinit like 'set
editing on' or 'off'.  */
    async_command_editing_p = 1;
 
    /* When a character is detected on instream by select or poll,
readline will be invoked via this callback function.  */
    call_readline = rl_callback_read_char_wrapper;
  }
else
  {
    async_command_editing_p = 0;
    call_readline = gdb_readline2;
  }

/* When readline has read an end-of-line character, it passes the
   complete line to gdb for processing. command_line_handler is the
   function that does this.  */
input_handler = command_line_handler;
    
/* Tell readline to use the same input stream that gdb uses. */
rl_instream = instream;

/* Get a file descriptor for the input stream, so that we can
   register it with the event loop.  */
input_fd = fileno (instream)(!__isthreaded ? ((instream)->_file) : (fileno)(instream));

/* Now we need to create the event sources for the input file
   descriptor.  */
/* At this point in time, this is the only event source that we
   register with the even loop. Another source is going to be the
   target program (inferior), but that must be registered only when
   it actually exists (I.e. after we say 'run' or after we connect
   to a remote target.  */
add_file_handler (input_fd, stdin_event_handler, 0);
1154}

1156/* Disable command input through the standard CLI channels.  Used in
 the suspend proc for interpreters that use the standard gdb readline
 interface, like the cli & the mi.  */
1159void
1160gdb_disable_readline (void)
1161{
/* FIXME - It is too heavyweight to delete and remake these every
   time you run an interpreter that needs readline.  It is probably
   better to have the interpreters cache these, which in turn means
   that this needs to be moved into interpreter specific code.  */

1167#if 0
ui_file_delete (gdb_stdout);
ui_file_delete (gdb_stderr);
gdb_stdlog = NULL((void*)0);
gdb_stdtarg = NULL((void*)0);
1172#endif

rl_callback_handler_remove ();
delete_file_handler (input_fd);
1176}