path: root/kernel/debug/kdb/kdb_io.c

/*
 * Kernel Debugger Architecture Independent Console I/O handler
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
 * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/nmi.h>
#include <linux/delay.h>
#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/kallsyms.h>
#include "kdb_private.h"

#define CMD_BUFLEN 256
char kdb_prompt_str[CMD_BUFLEN];

int kdb_trap_printk;

static int kgdb_transition_check(char *buffer)
{
	if (buffer[0] != '+' && buffer[0] != '$') {
		KDB_STATE_SET(KGDB_TRANS);
		kdb_printf("%s", buffer);
	} else {
		int slen = strlen(buffer);
		if (slen > 3 && buffer[slen - 3] == '#') {
			kdb_gdb_state_pass(buffer);
			strcpy(buffer, "kgdb");
			KDB_STATE_SET(DOING_KGDB);
			return 1;
		}
	}
	return 0;
}

static int kdb_read_get_key(char *buffer, size_t bufsize)
{
#define ESCAPE_UDELAY 1000
#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
	char escape_data[5];	/* longest vt100 escape sequence is 4 bytes */
	char *ped = escape_data;
	int escape_delay = 0;
	get_char_func *f, *f_escape = NULL;
	int key;

	for (f = &kdb_poll_funcs[0]; ; ++f) {
		if (*f == NULL) {
			/* Reset NMI watchdog once per poll loop */
			touch_nmi_watchdog();
			f = &kdb_poll_funcs[0];
		}
		if (escape_delay == 2) {
			*ped = '\0';
			ped = escape_data;
			--escape_delay;
		}
		if (escape_delay == 1) {
			key = *ped++;
			if (!*ped)
				--escape_delay;
			break;
		}
		key = (*f)();
		if (key == -1) {
			if (escape_delay) {
				udelay(ESCAPE_UDELAY);
				--escape_delay;
			}
			continue;
		}
		if (bufsize <= 2) {
			if (key == '\r')
				key = '\n';
			*buffer++ = key;
			*buffer = '\0';
			return -1;
		}
		if (escape_delay == 0 && key == '\e') {
			escape_delay = ESCAPE_DELAY;
			ped = escape_data;
			f_escape = f;
		}
		if (escape_delay) {
			*ped++ = key;
			if (f_escape != f) {
				escape_delay = 2;
				continue;
			}
			if (ped - escape_data == 1) {
				/* \e */
				continue;
			} else if (ped - escape_data == 2) {
				/* \e<something> */
				if (key != '[')
					escape_delay = 2;
				continue;
			} else if (ped - escape_data == 3) {
				/* \e[<something> */
				int mapkey = 0;
				switch (key) {
				case 'A': /* \e[A, up arrow */
					mapkey = 16;
					break;
				case 'B': /* \e[B, down arrow */
					mapkey = 14;
					break;
				case 'C': /* \e[C, right arrow */
					mapkey = 6;
					break;
				case 'D': /* \e[D, left arrow */
					mapkey = 2;
					break;
				case '1': /* dropthrough */
				case '3': /* dropthrough */
				/* \e[<1,3,4>], may be home, del, end */
				case '4':
					mapkey = -1;
					break;
				}
				if (mapkey != -1) {
					if (mapkey > 0) {
						escape_data[0] = mapkey;
						escape_data[1] = '\0';
					}
					escape_delay = 2;
				}
				continue;
			} else if (ped - escape_data == 4) {
				/* \e[<1,3,4><something> */
				int mapkey = 0;
				if (key == '~') {
					switch (escape_data[2]) {
					case '1': /* \e[1~, home */
						mapkey = 1;
						break;
					case '3': /* \e[3~, del */
						mapkey = 4;
						break;
					case '4': /* \e[4~, end */
						mapkey = 5;
						break;
					}
				}
				if (mapkey > 0) {
					escape_data[0] = mapkey;
					escape_data[1] = '\0';
				}
				escape_delay = 2;
				continue;
			}
		}
		break;	/* A key to process */
	}
	return key;
}

/*
 * kdb_read
 *
 *	This function reads a string of characters, terminated by
 *	a newline, or by reaching the end of the supplied buffer,
 *	from the current kernel debugger console device.
 * Parameters:
 *	buffer	- Address of character buffer to receive input characters.
 *	bufsize - size, in bytes, of the character buffer
 * Returns:
 *	Returns a pointer to the buffer containing the received
 *	character string.  This string will be terminated by a
 *	newline character.
 * Locking:
 *	No locks are required to be held