src/debugger/debugger.c

/*
 *  Copyright (C) 2004-2007  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *
 *
 *  $Id: debugger.c,v 1.22 2007/03/26 02:01:36 debug Exp $
 *
 *  Single-step debugger.
 *
 *
 *  TODO:
 *
 *      This entire module is very much non-reentrant. :-/
 *
 *      Add more functionality that already exists elsewhere in the emulator.
 *
 *      Call stack display (back-trace)?
 *
 *      Nicer looking output of register dumps, floating point registers,
 *      etc. Warn about weird/invalid register contents.
 *
 *      Ctrl-C doesn't enter the debugger on some OSes (HP-UX?)...
 *
 *      Many other TODOs.
 */

#include <ctype.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "console.h"
#include "cpu.h"
#include "device.h"
#include "debugger.h"
#include "diskimage.h"
#include "emul.h"
#include "machine.h"
#include "memory.h"
#include "misc.h"
#include "net.h"
#include "settings.h"
#include "timer.h"
#include "x11.h"


extern int extra_argc;
extern char **extra_argv;
extern struct settings *global_settings;
extern int quiet_mode;


/*
 *  Global debugger variables:
 *
 *  TODO: Some of these should be moved to some other place!
 */

volatile int single_step = NOT_SINGLE_STEPPING;
volatile int exit_debugger;
int force_debugger_at_exit = 0;

volatile int single_step_breakpoint = 0;
int debugger_n_steps_left_before_interaction = 0;

int old_instruction_trace = 0;
int old_quiet_mode = 0;
int old_show_trace_tree = 0;


/*
 *  Private (global) debugger variables:
 */

static volatile int ctrl_c;

static int debugger_n_emuls;
static struct emul **debugger_emuls;

/*  Currently focused CPU, machine, and emulation:  */
int debugger_cur_cpu;
int debugger_cur_machine;
int debugger_cur_emul;
static struct machine *debugger_machine;
static struct emul *debugger_emul;

#define MAX_CMD_BUFLEN          72
#define N_PREVIOUS_CMDS         150
static char *last_cmd[N_PREVIOUS_CMDS];
static int last_cmd_index;

static char repeat_cmd[MAX_CMD_BUFLEN];

#define MAGIC_UNTOUCHED         0x98ca76c2ffcc0011ULL

static uint64_t last_dump_addr = MAGIC_UNTOUCHED;
static uint64_t last_unasm_addr = MAGIC_UNTOUCHED;


/*
 *  debugger_readchar():
 */
char debugger_readchar(void)
{
        int ch;

        while ((ch = console_readchar(MAIN_CONSOLE)) < 0 && !exit_debugger) {
                /*  Check for X11 events:  */
                x11_check_event(debugger_emuls, debugger_n_emuls);

                /*  Give up some CPU time:  */
                usleep(10000);
        }
        return ch;
}


/*
 *  debugger_activate():
 *
 *  This is a signal handler for CTRL-C.  It shouldn't be called directly,
 *  but setup code in emul.c sets the CTRL-C signal handler to use this
 *  function.
 */
void debugger_activate(int x)
{
        ctrl_c = 1;

        if (single_step != NOT_SINGLE_STEPPING) {
                /*  Already in the debugger. Do nothing.  */
                int i;
                for (i=0; i<MAX_CMD_BUFLEN; i++)
                        console_makeavail(MAIN_CONSOLE, '\b');
                console_makeavail(MAIN_CONSOLE, ' ');
                console_makeavail(MAIN_CONSOLE, '\n');
                printf("^C");
                fflush(stdout);
        } else {
                /*  Enter the single step debugger.  */
                single_step = ENTER_SINGLE_STEPPING;

                /*  Discard any chars in the input queue:  */
                while (console_charavail(MAIN_CONSOLE))
                        console_readchar(MAIN_CONSOLE);
        }

        /*  Clear the repeat-command buffer:  */
        repeat_cmd[0] = '\0';

        /*  Reactivate the signal handler:  */
        signal(SIGINT, debugger_activate);
}


/*
 *  show_breakpoint():
 */
static void show_breakpoint(struct machine *m, int i)
{
        printf("%3i: 0x", i);
        if (m->cpus[0]->is_32bit)
                printf("%08"PRIx32, (uint32_t) m->breakpoint_addr[i]);
        else
                printf("%016"PRIx64, (uint64_t) m->breakpoint_addr[i]);
        if (m->breakpoint_string[i] != NULL)
                printf(" (%s)", m->breakpoint_string[i]);
        if (m->breakpoint_flags[i])
                printf(": flags=0x%x", m->breakpoint_flags[i]);
        printf("\n");
}


/****************************************************************************/


#include "debugger_cmds.c"


/****************************************************************************/


/*
 *  debugger_assignment():
 *
 *  cmd contains something like "pc=0x80001000", or "r31=memcpy+0x40".
 */
void debugger_assignment(struct machine *m, char *cmd)
{
        char *left, *right;
        int res_left, res_right;
        uint64_t tmp;
        uint64_t old_pc = m->cpus[0]->pc;       /*  TODO: multiple cpus?  */

        left  = malloc(MAX_CMD_BUFLEN);
        if (left == NULL) {
                fprintf(stderr, "out of memory in debugger_assignment()\n");
                exit(1);
        }
        strlcpy(left, cmd, MAX_CMD_BUFLEN);
        right = strchr(left, '=');
        if (right == NULL) {
                fprintf(stderr, "internal error in the debugger\n");
                exit(1);
        }
        *right = '\0';

        /*  Remove trailing spaces in left:  */
        while (strlen(left) >= 1 && left[strlen(left)-1] == ' ')
                left[strlen(left)-1] = '\0';

        /*  Remove leading spaces in right:  */
        right++;
        while (*right == ' ' && *right != '\0')
                right++;

        /*  printf("left  = '%s'\nright = '%s'\n", left, right);  */

        res_right = debugger_parse_expression(m, right, 0, &tmp);
        switch (res_right) {
        case PARSE_NOMATCH:
                printf("No match for the right-hand side of the assignment.\n");
                break;
        case PARSE_MULTIPLE:
                printf("Multiple matches for the right-hand side of the "
                    "assignment.\n");
                break;
        default:
                res_left = debugger_parse_expression(m, left, 1, &tmp);
                switch (res_left) {
                case PARSE_NOMATCH:
                        printf("No match for the left-hand side of the "
                            "assignment.\n");
                        break;
                case PARSE_MULTIPLE:
                        printf("Multiple matches for the left-hand side "
                            "of the assignment.\n");
                        break;
                default:
                        debugger_cmd_print(m, left);
                }
        }

        /*
         *  If the PC has changed, then release any breakpoint we were
         *  currently stopped at.
         *
         *  TODO: multiple cpus?
         */
        if (old_pc != m->cpus[0]->pc)
                single_step_breakpoint = 0;

        free(left);
}


/*
 *  debugger_execute_cmd():
 */
void debugger_execute_cmd(char *cmd, int cmd_len)
{
        int i, n, i_match, matchlen;

        /*
         *  Is there a '=' on the command line? Then try to do an
         *  assignment.  (Only if there is just one word, followed
         *  by the '=' sign. This makes it possible to use commands
         *  such as "device add name addr=xyz".)
         */
        if (strchr(cmd, '=') != NULL) {
                /*  Count the nr of words:  */
                int nw = 0, inword = 0;
                char *p = cmd;
                while (*p) {
                        if (*p == '=')
                                break;
                        if (*p != ' ') {
                                if (!inword)
                                        nw ++;
                                inword = 1;
                        } else
                                inword = 0;
                        p++;
                }

                if (nw == 1) {
                        debugger_assignment(debugger_machine, cmd);
                        return;
                }
        }

        i = 0;
        while (cmds[i].name != NULL)
                cmds[i++].tmp_flag = 0;

        /*  How many chars in cmd to match against:  */
        matchlen = 0;
        while (isalpha((int)cmd[matchlen]))
                matchlen ++;

        /*  Check for a command name match:  */
        n = i = i_match = 0;
        while (cmds[i].name != NULL) {
                if (strncasecmp(cmds[i].name, cmd, matchlen) == 0
                    && cmds[i].f != NULL) {
                        cmds[i].tmp_flag = 1;
                        i_match = i;
                        n++;
                }
                i++;
        }

        /*  No match?  */
        if (n == 0) {
                printf("Unknown command '%s'. Type 'help' for help.\n", cmd);
                return;
        }

        /*  More than one match?  */
        if (n > 1) {
                printf("Ambiguous command '%s':  ", cmd);
                i = 0;
                while (cmds[i].name != NULL) {
                        if (cmds[i].tmp_flag)
                                printf("  %s", cmds[i].name);
                        i++;
                }
                printf("\n");
                return;
        }

        /*  Exactly one match:  */
        if (cmds[i_match].f != NULL) {
                char *p = cmd + matchlen;
                /*  Remove leading whitespace from the args...  */
                while (*p != '\0' && *p == ' ')
                        p++;

                /*  ... and run the command:  */
                cmds[i_match].f(debugger_machine, p);
        } else
                printf("FATAL ERROR: internal error in debugger.c:"
                    " no handler for this command?\n");
}


/*
 *  debugger_readline():
 *
 *  Read a line from the terminal.
 */
static char *debugger_readline(void)
{
        int ch, i, j, n, i_match, reallen, cmd_len, cursor_pos;
        int read_from_index = last_cmd_index;
        char *cmd = last_cmd[last_cmd_index];

        cmd_len = 0; cmd[0] = '\0';
        printf("GXemul> ");
        fflush(stdout);

        ch = '\0';
        cmd_len = 0;
        cursor_pos = 0;

        while (ch != '\n' && !exit_debugger) {
                ch = debugger_readchar();

                if ((ch == '\b' || ch == 127) && cursor_pos > 0) {
                        /*  Backspace.  */
                        cursor_pos --;
                        cmd_len --;
                        memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
                            cmd_len);
                        cmd[cmd_len] = '\0';
                        printf("\b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        printf(" \b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == 4 && cmd_len > 0 && cursor_pos < cmd_len) {
                        /*  CTRL-D: Delete.  */
                        cmd_len --;
                        memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
                            cmd_len);
                        cmd[cmd_len] = '\0';
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        printf(" \b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == 1) {
                        /*  CTRL-A: Start of line.  */
                        while (cursor_pos > 0) {
                                cursor_pos --;
                                printf("\b");
                        }
                } else if (ch == 2) {
                        /*  CTRL-B: Backwards one character.  */
                        if (cursor_pos > 0) {
                                printf("\b");
                                cursor_pos --;
                        }
                } else if (ch == 5) {
                        /*  CTRL-E: End of line.  */
                        while (cursor_pos < cmd_len) {
                                printf("%c", cmd[cursor_pos]);
                                cursor_pos ++;
                        }
                } else if (ch == 6) {
                        /*  CTRL-F: Forward one character.  */
                        if (cursor_pos < cmd_len) {
                                printf("%c",
                                    cmd[cursor_pos]);
                                cursor_pos ++;
                        }
                } else if (ch == 11) {
                        /*  CTRL-K: Kill to end of line.  */
                        for (i=0; i<MAX_CMD_BUFLEN; i++)
                                console_makeavail(MAIN_CONSOLE, 4); /*  :-)  */
                } else if (ch == 14 || ch == 16) {
                        /*  CTRL-P: Previous line in the command history,
                            CTRL-N: next line  */
                        do {
                                if (ch == 14 &&
                                    read_from_index == last_cmd_index)
                                        break;
                                if (ch == 16)
                                        i = read_from_index - 1;
                                else
                                        i = read_from_index + 1;

                                if (i < 0)
                                        i = N_PREVIOUS_CMDS - 1;
                                if (i >= N_PREVIOUS_CMDS)
                                        i = 0;

                                /*  Special case: pressing 'down'
                                    to reach last_cmd_index:  */
                                if (i == last_cmd_index) {
                                        read_from_index = i;
                                        for (i=cursor_pos; i<cmd_len;
                                            i++)
                                                printf(" ");
                                        for (i=cmd_len-1; i>=0; i--)
                                                printf("\b \b");
                                        cmd[0] = '\0';
                                        cmd_len = cursor_pos = 0;
                                } else if (last_cmd[i][0] != '\0') {
                                        /*  Copy from old line:  */
                                        read_from_index = i;
                                        for (i=cursor_pos; i<cmd_len;
                                            i++)
                                                printf(" ");
                                        for (i=cmd_len-1; i>=0; i--)
                                                printf("\b \b");
                                        strlcpy(cmd,
                                            last_cmd[read_from_index],
                                            MAX_CMD_BUFLEN);
                                        cmd_len = strlen(cmd);
                                        printf("%s", cmd);
                                        cursor_pos = cmd_len;
                                }
                        } while (0);
                } else if (ch >= ' ' && cmd_len < MAX_CMD_BUFLEN-1) {
                        /*  Visible character:  */
                        memmove(cmd + cursor_pos + 1, cmd + cursor_pos,
                            cmd_len - cursor_pos);
                        cmd[cursor_pos] = ch;
                        cmd_len ++;
                        cursor_pos ++;
                        cmd[cmd_len] = '\0';
                        printf("%c", ch);
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == '\r' || ch == '\n') {
                        ch = '\n';
                        printf("\n");
                } else if (ch == '\t') {
                        /*  Super-simple tab-completion:  */
                        i = 0;
                        while (cmds[i].name != NULL)
                                cmds[i++].tmp_flag = 0;

                        /*  Check for a (partial) command match:  */
                        n = i = i_match = 0;
                        while (cmds[i].name != NULL) {
                                if (strncasecmp(cmds[i].name, cmd,
                                    cmd_len) == 0) {
                                        cmds[i].tmp_flag = 1;
                                        i_match = i;
                                        n++;
                                }
                                i++;
                        }

                        switch (n) {
                        case 0: /*  Beep.  */
                                printf("\a");
                                break;
                        case 1: /*  Add the rest of the command:  */
                                reallen = strlen(cmds[i_match].name);
                                for (i=cmd_len; i<reallen; i++)
                                        console_makeavail(MAIN_CONSOLE,
                                            cmds[i_match].name[i]);
                                /*  ... and a space, if the command takes
                                    any arguments:  */
                                if (cmds[i_match].args != NULL &&
                                    cmds[i_match].args[0] != '\0')
                                        console_makeavail(MAIN_CONSOLE, ' ');
                                break;
                        default:
                                /*  Show all possible commands:  */
                                printf("\a\n"); /*  Beep. :-)  */
                                i = 0;          /*  i = cmds index  */
                                j = 0;          /*  j = # of cmds printed  */
                                while (cmds[i].name != NULL) {
                                        if (cmds[i].tmp_flag) {
                                                size_t q;
                                                if (j == 0)
                                                        printf("  ");
                                                printf("%s",
                                                    cmds[i].name);
                                                j++;
                                                if (j != 6)
                                                        for (q=0; q<13-strlen(
                                                            cmds[i].name); q++)
                                                                printf(" ");
                                                if (j == 6) {
                                                        printf("\n");
                                                        j = 0;
                                                }
                                        }
                                        i++;
                                }
                                if (j != 0)
                                        printf("\n");
                                printf("GXemul> ");
                                for (i=0; i<cmd_len; i++)
                                        printf("%c", cmd[i]);
                        }
                } else if (ch == 27) {
                        /*  Escape codes: (cursor keys etc)  */
                        while ((ch = console_readchar(MAIN_CONSOLE)) < 0)
                                usleep(10000);
                        if (ch == '[' || ch == 'O') {
                                while ((ch = console_readchar(MAIN_CONSOLE))
                                    < 0)
                                        usleep(10000);
                                switch (ch) {
                                case '2':       /*  2~ = ins  */
                                case '5':       /*  5~ = pgup  */
                                case '6':       /*  6~ = pgdn  */
                                        /*  TODO: Ugly hack, but might work.  */
                                        while ((ch = console_readchar(
                                            MAIN_CONSOLE)) < 0)
                                                usleep(10000);
                                        /*  Do nothing for these keys.  */
                                        break;
                                case '3':       /*  3~ = delete  */
                                        /*  TODO: Ugly hack, but might work.  */
                                        while ((ch = console_readchar(
                                            MAIN_CONSOLE)) < 0)
                                                usleep(10000);
                                        console_makeavail(MAIN_CONSOLE, '\b');
                                        break;
                                case 'A':       /*  Up.  */
                                        /*  Up cursor ==> CTRL-P  */
                                        console_makeavail(MAIN_CONSOLE, 16);
                                        break;
                                case 'B':       /*  Down.  */
                                        /*  Down cursor ==> CTRL-N  */
                                        console_makeavail(MAIN_CONSOLE, 14);
                                        break;
                                case 'C':
                                        /*  Right cursor ==> CTRL-F  */
                                        console_makeavail(MAIN_CONSOLE, 6);
                                        break;
                                case 'D':       /*  Left  */
                                        /*  Left cursor ==> CTRL-B  */
                                        console_makeavail(MAIN_CONSOLE, 2);
                                        break;
                                case 'F':
                                        /*  End ==> CTRL-E  */
                                        console_makeavail(MAIN_CONSOLE, 5);
                                        break;
                                case 'H':
                                        /*  Home ==> CTRL-A  */
                                        console_makeavail(MAIN_CONSOLE, 1);
                                        break;
                                }
                        }
                }

                fflush(stdout);
        }

        if (exit_debugger)
                cmd[0] = '\0';

        return cmd;
}


/*
 *  debugger():
 *
 *  This is a loop, which reads a command from the terminal, and executes it.
 */
void debugger(void)
{
        int i, cmd_len;
        char *cmd;

        if (debugger_n_steps_left_before_interaction > 0) {
                debugger_n_steps_left_before_interaction --;
                return;
        }

        /*
         *  Clear all dyntrans translations, because otherwise things would
         *  become to complex to keep in sync.
         */
        /*  TODO: In all machines  */
        for (i=0; i<debugger_machine->ncpus; i++)
                if (debugger_machine->cpus[i]->translation_cache != NULL) {
                        cpu_create_or_reset_tc(debugger_machine->cpus[i]);
                        debugger_machine->cpus[i]->
                            invalidate_translation_caches(
                            debugger_machine->cpus[i], 0, INVALIDATE_ALL);
                }

        /*  Stop timers while interacting with the user:  */
        timer_stop();

        exit_debugger = 0;

        while (!exit_debugger) {
                /*  Read a line from the terminal:  */
                cmd = debugger_readline();

                cmd_len = strlen(cmd);

                /*  Remove spaces:  */
                while (cmd_len > 0 && cmd[0]==' ')
                        memmove(cmd, cmd+1, cmd_len --);
                while (cmd_len > 0 && cmd[cmd_len-1] == ' ')
                        cmd[(cmd_len--)-1] = '\0';

                /*  No command? Then try reading another line.  */
                if (cmd_len == 0) {
                        /*  Special case for repeated commands:  */
                        if (repeat_cmd[0] != '\0')
                                strlcpy(cmd, repeat_cmd, MAX_CMD_BUFLEN);
                        else
                                continue;
                } else {
                        last_cmd_index ++;
                        if (last_cmd_index >= N_PREVIOUS_CMDS)
                                last_cmd_index = 0;

                        repeat_cmd[0] = '\0';
                }

                debugger_execute_cmd(cmd, cmd_len);

                /*  Special hack for the "step" command:  */
                if (exit_debugger == -1)
                        return;
        }

        /*  Start up timers again:  */
        timer_start();

        /*  ... and reset starttime, so that nr of instructions per second
            can be calculated correctly:  */
        gettimeofday(&debugger_machine->starttime, NULL);
        debugger_machine->ninstrs_since_gettimeofday = 0;

        single_step = NOT_SINGLE_STEPPING;
        debugger_machine->instruction_trace = old_instruction_trace;
        debugger_machine->show_trace_tree = old_show_trace_tree;
        quiet_mode = old_quiet_mode;
}


/*
 *  debugger_reset():
 *
 *  This function should be called before calling debugger(), when it is
 *  absolutely necessary that debugger() is interactive. Otherwise, it might
 *  return without doing anything, such as when single-stepping multiple
 *  instructions at a time.
 */
void debugger_reset(void)
{
        debugger_n_steps_left_before_interaction = 0;
}


/*
 *  debugger_init():
 *
 *  Must be called before any other debugger function is used.
 */
void debugger_init(struct emul **emuls, int n_emuls)
{
        int i;

        debugger_n_emuls = n_emuls;
        debugger_emuls = emuls;

        if (n_emuls < 1) {
                fprintf(stderr, "\nERROR: No emuls (?)\n");
                exit(1);
        }

        debugger_emul = emuls[0];
        if (emuls[0]->n_machines < 1) {
                fprintf(stderr, "\nERROR: No machines in emuls[0], "
                    "cannot handle this situation yet.\n\n");
                exit(1);
        }

        debugger_machine = emuls[0]->machines[0];

        debugger_cur_cpu = 0;
        debugger_cur_machine = 0;
        debugger_cur_emul = 0;

        for (i=0; i<N_PREVIOUS_CMDS; i++) {
                last_cmd[i] = malloc(MAX_CMD_BUFLEN);
                if (last_cmd[i] == NULL) {
                        fprintf(stderr, "debugger_init(): out of memory\n");
                        exit(1);
                }
                last_cmd[i][0] = '\0';
        }

        last_cmd_index = 0;
        repeat_cmd[0] = '\0';
}

1	dpavlin	24	/*
2	dpavlin	34	* Copyright (C) 2004-2007 Anders Gavare. All rights reserved.
3	dpavlin	24	*
4			* Redistribution and use in source and binary forms, with or without
5			* modification, are permitted provided that the following conditions are met:
6			*
7			* 1. Redistributions of source code must retain the above copyright
8			* notice, this list of conditions and the following disclaimer.
9			* 2. Redistributions in binary form must reproduce the above copyright
10			* notice, this list of conditions and the following disclaimer in the
11			* documentation and/or other materials provided with the distribution.
12			* 3. The name of the author may not be used to endorse or promote products
13			* derived from this software without specific prior written permission.
14			*
15			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18			* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25			* SUCH DAMAGE.
26			*
27			*
28	dpavlin	38	* $Id: debugger.c,v 1.22 2007/03/26 02:01:36 debug Exp $
29	dpavlin	24	*
30			* Single-step debugger.
31			*
32			*
33			* TODO:
34			*
35			* This entire module is very much non-reentrant. :-/
36			*
37			* Add more functionality that already exists elsewhere in the emulator.
38			*
39			* Call stack display (back-trace)?
40			*
41			* Nicer looking output of register dumps, floating point registers,
42			* etc. Warn about weird/invalid register contents.
43			*
44			* Ctrl-C doesn't enter the debugger on some OSes (HP-UX?)...
45			*
46			* Many other TODOs.
47			*/
48
49			#include <ctype.h>
50			#include <signal.h>
51			#include <stdio.h>
52			#include <stdlib.h>
53			#include <string.h>
54			#include <unistd.h>
55
56			#include "console.h"
57			#include "cpu.h"
58			#include "device.h"
59			#include "debugger.h"
60			#include "diskimage.h"
61			#include "emul.h"
62			#include "machine.h"
63			#include "memory.h"
64			#include "misc.h"
65			#include "net.h"
66			#include "settings.h"
67	dpavlin	32	#include "timer.h"
68	dpavlin	24	#include "x11.h"
69
70
71			extern int extra_argc;
72			extern char **extra_argv;
73			extern struct settings *global_settings;
74			extern int quiet_mode;
75
76
77			/*
78			* Global debugger variables:
79			*
80			* TODO: Some of these should be moved to some other place!
81			*/
82
83	dpavlin	26	volatile int single_step = NOT_SINGLE_STEPPING;
84	dpavlin	24	volatile int exit_debugger;
85			int force_debugger_at_exit = 0;
86
87			volatile int single_step_breakpoint = 0;
88			int debugger_n_steps_left_before_interaction = 0;
89
90			int old_instruction_trace = 0;
91			int old_quiet_mode = 0;
92			int old_show_trace_tree = 0;
93
94
95			/*
96			* Private (global) debugger variables:
97			*/
98
99			static volatile int ctrl_c;
100
101			static int debugger_n_emuls;
102			static struct emul **debugger_emuls;
103	dpavlin	32
104			/* Currently focused CPU, machine, and emulation: */
105			int debugger_cur_cpu;
106			int debugger_cur_machine;
107			int debugger_cur_emul;
108			static struct machine *debugger_machine;
109	dpavlin	24	static struct emul *debugger_emul;
110
111			#define MAX_CMD_BUFLEN 72
112			#define N_PREVIOUS_CMDS 150
113			static char *last_cmd[N_PREVIOUS_CMDS];
114			static int last_cmd_index;
115
116			static char repeat_cmd[MAX_CMD_BUFLEN];
117
118			#define MAGIC_UNTOUCHED 0x98ca76c2ffcc0011ULL
119
120			static uint64_t last_dump_addr = MAGIC_UNTOUCHED;
121			static uint64_t last_unasm_addr = MAGIC_UNTOUCHED;
122
123
124			/*
125			* debugger_readchar():
126			*/
127			char debugger_readchar(void)
128			{
129	dpavlin	38	int ch;
130	dpavlin	24
131			while ((ch = console_readchar(MAIN_CONSOLE)) < 0 && !exit_debugger) {
132			/* Check for X11 events: */
133			x11_check_event(debugger_emuls, debugger_n_emuls);
134
135			/* Give up some CPU time: */
136	dpavlin	32	usleep(10000);
137	dpavlin	24	}
138			return ch;
139			}
140
141
142			/*
143			* debugger_activate():
144			*
145			* This is a signal handler for CTRL-C. It shouldn't be called directly,
146			* but setup code in emul.c sets the CTRL-C signal handler to use this
147			* function.
148			*/
149			void debugger_activate(int x)
150			{
151			ctrl_c = 1;
152
153	dpavlin	26	if (single_step != NOT_SINGLE_STEPPING) {
154	dpavlin	24	/* Already in the debugger. Do nothing. */
155			int i;
156			for (i=0; i<MAX_CMD_BUFLEN; i++)
157			console_makeavail(MAIN_CONSOLE, '\b');
158			console_makeavail(MAIN_CONSOLE, ' ');
159			console_makeavail(MAIN_CONSOLE, '\n');
160			printf("^C");
161			fflush(stdout);
162			} else {
163			/* Enter the single step debugger. */
164	dpavlin	26	single_step = ENTER_SINGLE_STEPPING;
165	dpavlin	24
166			/* Discard any chars in the input queue: */
167			while (console_charavail(MAIN_CONSOLE))
168			console_readchar(MAIN_CONSOLE);
169			}
170
171			/* Clear the repeat-command buffer: */
172			repeat_cmd[0] = '\0';
173
174			/* Reactivate the signal handler: */
175			signal(SIGINT, debugger_activate);
176			}
177
178
179			/*
180			* show_breakpoint():
181			*/
182			static void show_breakpoint(struct machine *m, int i)
183			{
184			printf("%3i: 0x", i);
185			if (m->cpus[0]->is_32bit)
186			printf("%08"PRIx32, (uint32_t) m->breakpoint_addr[i]);
187			else
188			printf("%016"PRIx64, (uint64_t) m->breakpoint_addr[i]);
189			if (m->breakpoint_string[i] != NULL)
190			printf(" (%s)", m->breakpoint_string[i]);
191			if (m->breakpoint_flags[i])
192			printf(": flags=0x%x", m->breakpoint_flags[i]);
193			printf("\n");
194			}
195
196
197			/****************************************************************************/
198
199
200			#include "debugger_cmds.c"
201
202
203			/****************************************************************************/
204
205
206			/*
207			* debugger_assignment():
208			*
209			* cmd contains something like "pc=0x80001000", or "r31=memcpy+0x40".
210			*/
211			void debugger_assignment(struct machine m, char cmd)
212			{
213			char left, right;
214			int res_left, res_right;
215			uint64_t tmp;
216			uint64_t old_pc = m->cpus[0]->pc; /* TODO: multiple cpus? */
217
218			left = malloc(MAX_CMD_BUFLEN);
219			if (left == NULL) {
220			fprintf(stderr, "out of memory in debugger_assignment()\n");
221			exit(1);
222			}
223			strlcpy(left, cmd, MAX_CMD_BUFLEN);
224			right = strchr(left, '=');
225			if (right == NULL) {
226			fprintf(stderr, "internal error in the debugger\n");
227			exit(1);
228			}
229			*right = '\0';
230
231			/* Remove trailing spaces in left: */
232			while (strlen(left) >= 1 && left[strlen(left)-1] == ' ')
233			left[strlen(left)-1] = '\0';
234
235			/* Remove leading spaces in right: */
236			right++;
237			while (right == ' ' && right != '\0')
238			right++;
239
240			/* printf("left = '%s'\nright = '%s'\n", left, right); */
241
242	dpavlin	32	res_right = debugger_parse_expression(m, right, 0, &tmp);
243	dpavlin	24	switch (res_right) {
244	dpavlin	32	case PARSE_NOMATCH:
245	dpavlin	24	printf("No match for the right-hand side of the assignment.\n");
246			break;
247	dpavlin	32	case PARSE_MULTIPLE:
248	dpavlin	24	printf("Multiple matches for the right-hand side of the "
249			"assignment.\n");
250			break;
251			default:
252	dpavlin	32	res_left = debugger_parse_expression(m, left, 1, &tmp);
253	dpavlin	24	switch (res_left) {
254	dpavlin	32	case PARSE_NOMATCH:
255	dpavlin	24	printf("No match for the left-hand side of the "
256			"assignment.\n");
257			break;
258	dpavlin	32	case PARSE_MULTIPLE:
259	dpavlin	24	printf("Multiple matches for the left-hand side "
260			"of the assignment.\n");
261			break;
262			default:
263			debugger_cmd_print(m, left);
264			}
265			}
266
267			/*
268			* If the PC has changed, then release any breakpoint we were
269			* currently stopped at.
270			*
271			* TODO: multiple cpus?
272			*/
273			if (old_pc != m->cpus[0]->pc)
274			single_step_breakpoint = 0;
275
276			free(left);
277			}
278
279
280			/*
281			* debugger_execute_cmd():
282			*/
283			void debugger_execute_cmd(char *cmd, int cmd_len)
284			{
285			int i, n, i_match, matchlen;
286
287			/*
288			* Is there a '=' on the command line? Then try to do an
289			* assignment. (Only if there is just one word, followed
290			* by the '=' sign. This makes it possible to use commands
291			* such as "device add name addr=xyz".)
292			*/
293			if (strchr(cmd, '=') != NULL) {
294			/* Count the nr of words: */
295			int nw = 0, inword = 0;
296			char *p = cmd;
297			while (*p) {
298			if (*p == '=')
299			break;
300			if (*p != ' ') {
301			if (!inword)
302			nw ++;
303			inword = 1;
304			} else
305			inword = 0;
306			p++;
307			}
308
309			if (nw == 1) {
310			debugger_assignment(debugger_machine, cmd);
311			return;
312			}
313			}
314
315			i = 0;
316			while (cmds[i].name != NULL)
317			cmds[i++].tmp_flag = 0;
318
319			/* How many chars in cmd to match against: */
320			matchlen = 0;
321			while (isalpha((int)cmd[matchlen]))
322			matchlen ++;
323
324			/* Check for a command name match: */
325			n = i = i_match = 0;
326			while (cmds[i].name != NULL) {
327			if (strncasecmp(cmds[i].name, cmd, matchlen) == 0
328			&& cmds[i].f != NULL) {
329			cmds[i].tmp_flag = 1;
330			i_match = i;
331			n++;
332			}
333			i++;
334			}
335
336			/* No match? */
337			if (n == 0) {
338			printf("Unknown command '%s'. Type 'help' for help.\n", cmd);
339			return;
340			}
341
342			/* More than one match? */
343			if (n > 1) {
344			printf("Ambiguous command '%s': ", cmd);
345			i = 0;
346			while (cmds[i].name != NULL) {
347			if (cmds[i].tmp_flag)
348			printf(" %s", cmds[i].name);
349			i++;
350			}
351			printf("\n");
352			return;
353			}
354
355			/* Exactly one match: */
356			if (cmds[i_match].f != NULL) {
357			char *p = cmd + matchlen;
358			/* Remove leading whitespace from the args... */
359			while (p != '\0' && p == ' ')
360			p++;
361
362			/* ... and run the command: */
363			cmds[i_match].f(debugger_machine, p);
364			} else
365			printf("FATAL ERROR: internal error in debugger.c:"
366			" no handler for this command?\n");
367			}
368
369
370			/*
371			* debugger_readline():
372			*
373			* Read a line from the terminal.
374			*/
375			static char *debugger_readline(void)
376			{
377			int ch, i, j, n, i_match, reallen, cmd_len, cursor_pos;
378			int read_from_index = last_cmd_index;
379			char *cmd = last_cmd[last_cmd_index];
380
381			cmd_len = 0; cmd[0] = '\0';
382			printf("GXemul> ");
383			fflush(stdout);
384
385			ch = '\0';
386			cmd_len = 0;
387			cursor_pos = 0;
388
389			while (ch != '\n' && !exit_debugger) {
390			ch = debugger_readchar();
391
392			if ((ch == '\b' \|\| ch == 127) && cursor_pos > 0) {
393			/* Backspace. */
394			cursor_pos --;
395			cmd_len --;
396			memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
397			cmd_len);
398			cmd[cmd_len] = '\0';
399			printf("\b");
400			for (i=cursor_pos; i<cmd_len; i++)
401			printf("%c", cmd[i]);
402			printf(" \b");
403			for (i=cursor_pos; i<cmd_len; i++)
404			printf("\b");
405			} else if (ch == 4 && cmd_len > 0 && cursor_pos < cmd_len) {
406			/* CTRL-D: Delete. */
407			cmd_len --;
408			memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
409			cmd_len);
410			cmd[cmd_len] = '\0';
411			for (i=cursor_pos; i<cmd_len; i++)
412			printf("%c", cmd[i]);
413			printf(" \b");
414			for (i=cursor_pos; i<cmd_len; i++)
415			printf("\b");
416			} else if (ch == 1) {
417			/* CTRL-A: Start of line. */
418			while (cursor_pos > 0) {
419			cursor_pos --;
420			printf("\b");
421			}
422			} else if (ch == 2) {
423			/* CTRL-B: Backwards one character. */
424			if (cursor_pos > 0) {
425			printf("\b");
426			cursor_pos --;
427			}
428			} else if (ch == 5) {
429			/* CTRL-E: End of line. */
430			while (cursor_pos < cmd_len) {
431			printf("%c", cmd[cursor_pos]);
432			cursor_pos ++;
433			}
434			} else if (ch == 6) {
435			/* CTRL-F: Forward one character. */
436			if (cursor_pos < cmd_len) {
437			printf("%c",
438			cmd[cursor_pos]);
439			cursor_pos ++;
440			}
441			} else if (ch == 11) {
442			/* CTRL-K: Kill to end of line. */
443			for (i=0; i<MAX_CMD_BUFLEN; i++)
444			console_makeavail(MAIN_CONSOLE, 4); /* :-) */
445			} else if (ch == 14 \|\| ch == 16) {
446			/* CTRL-P: Previous line in the command history,
447			CTRL-N: next line */
448			do {
449			if (ch == 14 &&
450			read_from_index == last_cmd_index)
451			break;
452			if (ch == 16)
453			i = read_from_index - 1;
454			else
455			i = read_from_index + 1;
456
457			if (i < 0)
458			i = N_PREVIOUS_CMDS - 1;
459			if (i >= N_PREVIOUS_CMDS)
460			i = 0;
461
462			/* Special case: pressing 'down'
463			to reach last_cmd_index: */
464			if (i == last_cmd_index) {
465			read_from_index = i;
466			for (i=cursor_pos; i<cmd_len;
467			i++)
468			printf(" ");
469			for (i=cmd_len-1; i>=0; i--)
470			printf("\b \b");
471			cmd[0] = '\0';
472			cmd_len = cursor_pos = 0;
473			} else if (last_cmd[i][0] != '\0') {
474			/* Copy from old line: */
475			read_from_index = i;
476			for (i=cursor_pos; i<cmd_len;
477			i++)
478			printf(" ");
479			for (i=cmd_len-1; i>=0; i--)
480			printf("\b \b");
481			strlcpy(cmd,
482			last_cmd[read_from_index],
483			MAX_CMD_BUFLEN);
484			cmd_len = strlen(cmd);
485			printf("%s", cmd);
486			cursor_pos = cmd_len;
487			}
488			} while (0);
489			} else if (ch >= ' ' && cmd_len < MAX_CMD_BUFLEN-1) {
490			/* Visible character: */
491			memmove(cmd + cursor_pos + 1, cmd + cursor_pos,
492			cmd_len - cursor_pos);
493			cmd[cursor_pos] = ch;
494			cmd_len ++;
495			cursor_pos ++;
496			cmd[cmd_len] = '\0';
497			printf("%c", ch);
498			for (i=cursor_pos; i<cmd_len; i++)
499			printf("%c", cmd[i]);
500			for (i=cursor_pos; i<cmd_len; i++)
501			printf("\b");
502			} else if (ch == '\r' \|\| ch == '\n') {
503			ch = '\n';
504			printf("\n");
505			} else if (ch == '\t') {
506			/* Super-simple tab-completion: */
507			i = 0;
508			while (cmds[i].name != NULL)
509			cmds[i++].tmp_flag = 0;
510
511			/* Check for a (partial) command match: */
512			n = i = i_match = 0;
513			while (cmds[i].name != NULL) {
514			if (strncasecmp(cmds[i].name, cmd,
515			cmd_len) == 0) {
516			cmds[i].tmp_flag = 1;
517			i_match = i;
518			n++;
519			}
520			i++;
521			}
522
523			switch (n) {
524			case 0: /* Beep. */
525			printf("\a");
526			break;
527			case 1: /* Add the rest of the command: */
528			reallen = strlen(cmds[i_match].name);
529			for (i=cmd_len; i<reallen; i++)
530			console_makeavail(MAIN_CONSOLE,
531			cmds[i_match].name[i]);
532			/* ... and a space, if the command takes
533			any arguments: */
534			if (cmds[i_match].args != NULL &&
535			cmds[i_match].args[0] != '\0')
536			console_makeavail(MAIN_CONSOLE, ' ');
537			break;
538			default:
539			/* Show all possible commands: */
540			printf("\a\n"); /* Beep. :-) */
541			i = 0; /* i = cmds index */
542			j = 0; /* j = # of cmds printed */
543			while (cmds[i].name != NULL) {
544			if (cmds[i].tmp_flag) {
545			size_t q;
546			if (j == 0)
547			printf(" ");
548			printf("%s",
549			cmds[i].name);
550			j++;
551			if (j != 6)
552			for (q=0; q<13-strlen(
553			cmds[i].name); q++)
554			printf(" ");
555			if (j == 6) {
556			printf("\n");
557			j = 0;
558			}
559			}
560			i++;
561			}
562			if (j != 0)
563			printf("\n");
564			printf("GXemul> ");
565			for (i=0; i<cmd_len; i++)
566			printf("%c", cmd[i]);
567			}
568			} else if (ch == 27) {
569			/* Escape codes: (cursor keys etc) */
570			while ((ch = console_readchar(MAIN_CONSOLE)) < 0)
571	dpavlin	32	usleep(10000);
572	dpavlin	24	if (ch == '[' \|\| ch == 'O') {
573			while ((ch = console_readchar(MAIN_CONSOLE))
574			< 0)
575	dpavlin	32	usleep(10000);
576	dpavlin	24	switch (ch) {
577			case '2': /* 2~ = ins */
578			case '5': /* 5~ = pgup */
579			case '6': /* 6~ = pgdn */
580			/* TODO: Ugly hack, but might work. */
581			while ((ch = console_readchar(
582			MAIN_CONSOLE)) < 0)
583	dpavlin	32	usleep(10000);
584	dpavlin	24	/* Do nothing for these keys. */
585			break;
586			case '3': /* 3~ = delete */
587			/* TODO: Ugly hack, but might work. */
588			while ((ch = console_readchar(
589			MAIN_CONSOLE)) < 0)
590	dpavlin	32	usleep(10000);
591	dpavlin	24	console_makeavail(MAIN_CONSOLE, '\b');
592			break;
593			case 'A': /* Up. */
594			/* Up cursor ==> CTRL-P */
595			console_makeavail(MAIN_CONSOLE, 16);
596			break;
597			case 'B': /* Down. */
598			/* Down cursor ==> CTRL-N */
599			console_makeavail(MAIN_CONSOLE, 14);
600			break;
601			case 'C':
602			/* Right cursor ==> CTRL-F */
603			console_makeavail(MAIN_CONSOLE, 6);
604			break;
605			case 'D': /* Left */
606			/* Left cursor ==> CTRL-B */
607			console_makeavail(MAIN_CONSOLE, 2);
608			break;
609			case 'F':
610			/* End ==> CTRL-E */
611			console_makeavail(MAIN_CONSOLE, 5);
612			break;
613			case 'H':
614			/* Home ==> CTRL-A */
615			console_makeavail(MAIN_CONSOLE, 1);
616			break;
617			}
618			}
619			}
620
621			fflush(stdout);
622			}
623
624			if (exit_debugger)
625			cmd[0] = '\0';
626
627			return cmd;
628			}
629
630
631			/*
632			* debugger():
633			*
634			* This is a loop, which reads a command from the terminal, and executes it.
635			*/
636			void debugger(void)
637			{
638			int i, cmd_len;
639			char *cmd;
640
641			if (debugger_n_steps_left_before_interaction > 0) {
642			debugger_n_steps_left_before_interaction --;
643			return;
644			}
645
646			/*
647			* Clear all dyntrans translations, because otherwise things would
648			* become to complex to keep in sync.
649			*/
650			/* TODO: In all machines */
651			for (i=0; i<debugger_machine->ncpus; i++)
652	dpavlin	26	if (debugger_machine->cpus[i]->translation_cache != NULL) {
653	dpavlin	24	cpu_create_or_reset_tc(debugger_machine->cpus[i]);
654	dpavlin	26	debugger_machine->cpus[i]->
655			invalidate_translation_caches(
656			debugger_machine->cpus[i], 0, INVALIDATE_ALL);
657			}
658	dpavlin	24
659	dpavlin	32	/* Stop timers while interacting with the user: */
660			timer_stop();
661
662	dpavlin	24	exit_debugger = 0;
663
664			while (!exit_debugger) {
665			/* Read a line from the terminal: */
666			cmd = debugger_readline();
667
668			cmd_len = strlen(cmd);
669
670			/* Remove spaces: */
671			while (cmd_len > 0 && cmd[0]==' ')
672			memmove(cmd, cmd+1, cmd_len --);
673			while (cmd_len > 0 && cmd[cmd_len-1] == ' ')
674			cmd[(cmd_len--)-1] = '\0';
675
676			/* No command? Then try reading another line. */
677			if (cmd_len == 0) {
678			/* Special case for repeated commands: */
679			if (repeat_cmd[0] != '\0')
680			strlcpy(cmd, repeat_cmd, MAX_CMD_BUFLEN);
681			else
682			continue;
683			} else {
684			last_cmd_index ++;
685			if (last_cmd_index >= N_PREVIOUS_CMDS)
686			last_cmd_index = 0;
687
688			repeat_cmd[0] = '\0';
689			}
690
691			debugger_execute_cmd(cmd, cmd_len);
692
693			/* Special hack for the "step" command: */
694			if (exit_debugger == -1)
695			return;
696			}
697
698	dpavlin	32	/* Start up timers again: */
699			timer_start();
700
701			/* ... and reset starttime, so that nr of instructions per second
702			can be calculated correctly: */
703	dpavlin	24	gettimeofday(&debugger_machine->starttime, NULL);
704	dpavlin	28	debugger_machine->ninstrs_since_gettimeofday = 0;
705	dpavlin	24
706	dpavlin	26	single_step = NOT_SINGLE_STEPPING;
707	dpavlin	24	debugger_machine->instruction_trace = old_instruction_trace;
708			debugger_machine->show_trace_tree = old_show_trace_tree;
709			quiet_mode = old_quiet_mode;
710			}
711
712
713			/*
714			* debugger_reset():
715			*
716			* This function should be called before calling debugger(), when it is
717			* absolutely necessary that debugger() is interactive. Otherwise, it might
718			* return without doing anything, such as when single-stepping multiple
719			* instructions at a time.
720			*/
721			void debugger_reset(void)
722			{
723			debugger_n_steps_left_before_interaction = 0;
724			}
725
726
727			/*
728			* debugger_init():
729			*
730			* Must be called before any other debugger function is used.
731			*/
732			void debugger_init(struct emul **emuls, int n_emuls)
733			{
734	dpavlin	38	int i;
735	dpavlin	24
736			debugger_n_emuls = n_emuls;
737			debugger_emuls = emuls;
738
739			if (n_emuls < 1) {
740			fprintf(stderr, "\nERROR: No emuls (?)\n");
741			exit(1);
742			}
743
744			debugger_emul = emuls[0];
745			if (emuls[0]->n_machines < 1) {
746			fprintf(stderr, "\nERROR: No machines in emuls[0], "
747			"cannot handle this situation yet.\n\n");
748			exit(1);
749			}
750
751			debugger_machine = emuls[0]->machines[0];
752
753	dpavlin	32	debugger_cur_cpu = 0;
754			debugger_cur_machine = 0;
755			debugger_cur_emul = 0;
756
757	dpavlin	24	for (i=0; i<N_PREVIOUS_CMDS; i++) {
758			last_cmd[i] = malloc(MAX_CMD_BUFLEN);
759			if (last_cmd[i] == NULL) {
760			fprintf(stderr, "debugger_init(): out of memory\n");
761			exit(1);
762			}
763			last_cmd[i][0] = '\0';
764			}
765
766			last_cmd_index = 0;
767			repeat_cmd[0] = '\0';
768			}
769