freebsd-dev/sys/ddb/db_output.c
Ryan Libby 3e5e9939cd ddb: enable the use of ^C and ^S/^Q
This lets one interrupt DDB's output, which is useful if paging is
disabled and the output device is slow.

This follows a previous implementation in svn r311952 / git
5fddef7999 which was reverted because it
broke DDB type-ahead.

Now, try this again, but with a 512-byte type-ahead buffer.  While there
is buffer space, control input is handled and non-control input is
buffered.  When the buffer is exhausted, the default is to print a
warning and drop further non-control input in order to continue handling
control input.  sysctl debug.ddb.prioritize_control_input can be set to
0 to instead preserve all input but lose immediate handling of control
input.  This could for example effect pasting of a large script into the
ddb console.

Suggested by:	Anton Rang <rang@acm.org>
Reviewed by:	markj
Discussed with:	imp
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D28676
2021-03-14 16:04:27 -07:00

395 lines
8.0 KiB
C

/*-
* SPDX-License-Identifier: MIT-CMU
*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
/*
* Printf and character output for debugger.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/cons.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <machine/stdarg.h>
#include <ddb/ddb.h>
#include <ddb/db_output.h>
struct dbputchar_arg {
size_t da_nbufr;
size_t da_remain;
char *da_pbufr;
char *da_pnext;
};
/*
* Character output - tracks position in line.
* To do this correctly, we should know how wide
* the output device is - then we could zero
* the line position when the output device wraps
* around to the start of the next line.
*
* Instead, we count the number of spaces printed
* since the last printing character so that we
* don't print trailing spaces. This avoids most
* of the wraparounds.
*/
static int db_output_position = 0; /* output column */
static int db_last_non_space = 0; /* last non-space character */
db_expr_t db_tab_stop_width = 8; /* how wide are tab stops? */
#define NEXT_TAB(i) rounddown((i) + db_tab_stop_width, db_tab_stop_width)
db_expr_t db_max_width = 79; /* output line width */
db_expr_t db_lines_per_page = 20; /* lines per page */
volatile int db_pager_quit; /* user requested quit */
static int db_newlines; /* # lines this page */
static int db_maxlines; /* max lines/page when paging */
static int ddb_use_printf = 0;
SYSCTL_INT(_debug, OID_AUTO, ddb_use_printf, CTLFLAG_RW, &ddb_use_printf, 0,
"use printf for all ddb output");
static void db_putc(int c);
static void db_puts(const char *str);
static void db_putchar(int c, void *arg);
static void db_pager(void);
/*
* Force pending whitespace.
*/
void
db_force_whitespace(void)
{
int last_print, next_tab;
last_print = db_last_non_space;
while (last_print < db_output_position) {
next_tab = NEXT_TAB(last_print);
if (next_tab <= db_output_position) {
while (last_print < next_tab) { /* DON'T send a tab!!! */
cnputc(' ');
db_capture_writech(' ');
last_print++;
}
}
else {
cnputc(' ');
db_capture_writech(' ');
last_print++;
}
}
db_last_non_space = db_output_position;
}
/*
* Output character. Buffer whitespace.
*/
static void
db_putchar(int c, void *arg)
{
struct dbputchar_arg *dap = arg;
if (dap->da_pbufr == NULL) {
/* No bufferized output is provided. */
db_putc(c);
} else {
*dap->da_pnext++ = c;
dap->da_remain--;
/* Leave always the buffer 0 terminated. */
*dap->da_pnext = '\0';
/* Check if the buffer needs to be flushed. */
if (dap->da_remain < 2 || c == '\n') {
db_puts(dap->da_pbufr);
dap->da_pnext = dap->da_pbufr;
dap->da_remain = dap->da_nbufr;
*dap->da_pnext = '\0';
}
}
}
static void
db_putc(int c)
{
/*
* If not in the debugger or the user requests it, output data to
* both the console and the message buffer.
*/
if (!kdb_active || ddb_use_printf) {
printf("%c", c);
if (!kdb_active)
return;
if (c == '\r' || c == '\n')
db_check_interrupt();
if (c == '\n' && db_maxlines > 0) {
db_newlines++;
if (db_newlines >= db_maxlines)
db_pager();
}
return;
}
/* Otherwise, output data directly to the console. */
if (c > ' ' && c <= '~') {
/*
* Printing character.
* If we have spaces to print, print them first.
* Use tabs if possible.
*/
db_force_whitespace();
cnputc(c);
db_capture_writech(c);
db_output_position++;
db_last_non_space = db_output_position;
}
else if (c == '\n') {
/* Newline */
cnputc(c);
db_capture_writech(c);
db_output_position = 0;
db_last_non_space = 0;
db_check_interrupt();
if (db_maxlines > 0) {
db_newlines++;
if (db_newlines >= db_maxlines)
db_pager();
}
}
else if (c == '\r') {
/* Return */
cnputc(c);
db_capture_writech(c);
db_output_position = 0;
db_last_non_space = 0;
db_check_interrupt();
}
else if (c == '\t') {
/* assume tabs every 8 positions */
db_output_position = NEXT_TAB(db_output_position);
}
else if (c == ' ') {
/* space */
db_output_position++;
}
else if (c == '\007') {
/* bell */
cnputc(c);
/* No need to beep in a log: db_capture_writech(c); */
}
/* other characters are assumed non-printing */
}
static void
db_puts(const char *str)
{
int i;
for (i = 0; str[i] != '\0'; i++)
db_putc(str[i]);
}
/*
* Turn on the pager.
*/
void
db_enable_pager(void)
{
if (db_maxlines == 0) {
db_maxlines = db_lines_per_page;
db_newlines = 0;
db_pager_quit = 0;
}
}
/*
* Turn off the pager.
*/
void
db_disable_pager(void)
{
db_maxlines = 0;
}
/*
* A simple paging callout function. It supports several simple more(1)-like
* commands as well as a quit command that sets db_pager_quit which db
* commands can poll to see if they should terminate early.
*/
void
db_pager(void)
{
int c, done;
db_capture_enterpager();
db_printf("--More--\r");
done = 0;
while (!done) {
c = db_getc();
switch (c) {
case 'e':
case 'j':
case '\n':
/* Just one more line. */
db_maxlines = 1;
done++;
break;
case 'd':
/* Half a page. */
db_maxlines = db_lines_per_page / 2;
done++;
break;
case 'f':
case ' ':
/* Another page. */
db_maxlines = db_lines_per_page;
done++;
break;
case 'q':
case 'Q':
case 'x':
case 'X':
/* Quit */
db_maxlines = 0;
db_pager_quit = 1;
done++;
break;
#if 0
/* FALLTHROUGH */
default:
cnputc('\007');
#endif
}
}
db_printf(" ");
db_force_whitespace();
db_printf("\r");
db_newlines = 0;
db_capture_exitpager();
}
/*
* Return output position
*/
int
db_print_position(void)
{
return (db_output_position);
}
/*
* Printing
*/
int
db_printf(const char *fmt, ...)
{
#ifdef DDB_BUFR_SIZE
char bufr[DDB_BUFR_SIZE];
#endif
struct dbputchar_arg dca;
va_list listp;
int retval;
#ifdef DDB_BUFR_SIZE
dca.da_pbufr = bufr;
dca.da_pnext = dca.da_pbufr;
dca.da_nbufr = sizeof(bufr);
dca.da_remain = sizeof(bufr);
*dca.da_pnext = '\0';
#else
dca.da_pbufr = NULL;
#endif
va_start(listp, fmt);
retval = kvprintf (fmt, db_putchar, &dca, db_radix, listp);
va_end(listp);
#ifdef DDB_BUFR_SIZE
if (*dca.da_pbufr != '\0')
db_puts(dca.da_pbufr);
#endif
return (retval);
}
int db_indent;
void
db_iprintf(const char *fmt,...)
{
#ifdef DDB_BUFR_SIZE
char bufr[DDB_BUFR_SIZE];
#endif
struct dbputchar_arg dca;
int i;
va_list listp;
for (i = db_indent; i >= 8; i -= 8)
db_printf("\t");
while (--i >= 0)
db_printf(" ");
#ifdef DDB_BUFR_SIZE
dca.da_pbufr = bufr;
dca.da_pnext = dca.da_pbufr;
dca.da_nbufr = sizeof(bufr);
dca.da_remain = sizeof(bufr);
*dca.da_pnext = '\0';
#else
dca.da_pbufr = NULL;
#endif
va_start(listp, fmt);
kvprintf (fmt, db_putchar, &dca, db_radix, listp);
va_end(listp);
#ifdef DDB_BUFR_SIZE
if (*dca.da_pbufr != '\0')
db_puts(dca.da_pbufr);
#endif
}
/*
* End line if too long.
*/
void
db_end_line(int field_width)
{
if (db_output_position + field_width > db_max_width)
db_printf("\n");
}