freebsd-skq/sys/ddb/db_examine.c
markj 8cefad6db0 Don't return undefined symbols to a DDB symbol lookup.
Undefined symbols have a value of zero, so it makes no sense to return
such a symbol when performing a lookup by value. This occurs for example
when unwinding the stack after calling a NULL function pointer, and we
confusingly report the faulting function as uart_sab82532_class() on
amd64.

Convert db_print_loc_and_inst() to only attempt disassembly if we managed
to find a symbol corresponding to the IP. Otherwise we may fault and
re-enter the debugger.

Reviewed by:	jhb
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D2858
2015-07-21 23:07:55 +00:00

324 lines
7.0 KiB
C

/*-
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <ddb/ddb.h>
#include <ddb/db_lex.h>
#include <ddb/db_output.h>
#include <ddb/db_command.h>
#include <ddb/db_sym.h>
#include <ddb/db_access.h>
static char db_examine_format[TOK_STRING_SIZE] = "x";
static void db_examine(db_addr_t, char *, int);
static void db_search(db_addr_t, int, db_expr_t, db_expr_t, u_int);
/*
* Examine (print) data.
*/
/*ARGSUSED*/
void
db_examine_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
{
if (modif[0] != '\0')
db_strcpy(db_examine_format, modif);
if (count == -1)
count = 1;
db_examine((db_addr_t) addr, db_examine_format, count);
}
static void
db_examine(db_addr_t addr, char *fmt, int count)
{
int c;
db_expr_t value;
int size;
int width;
char * fp;
while (--count >= 0 && !db_pager_quit) {
fp = fmt;
size = 4;
while ((c = *fp++) != 0) {
switch (c) {
case 'b':
size = 1;
break;
case 'h':
size = 2;
break;
case 'l':
size = 4;
break;
case 'g':
size = 8;
break;
case 'a': /* address */
size = sizeof(void *);
/* always forces a new line */
if (db_print_position() != 0)
db_printf("\n");
db_prev = addr;
db_printsym(addr, DB_STGY_ANY);
db_printf(":\t");
break;
default:
if (db_print_position() == 0) {
/* Print the address. */
db_printsym(addr, DB_STGY_ANY);
db_printf(":\t");
db_prev = addr;
}
width = size * 4;
switch (c) {
case 'r': /* signed, current radix */
value = db_get_value(addr, size, true);
addr += size;
db_printf("%+-*lr", width, (long)value);
break;
case 'x': /* unsigned hex */
value = db_get_value(addr, size, false);
addr += size;
db_printf("%-*lx", width, (long)value);
break;
case 'z': /* signed hex */
value = db_get_value(addr, size, true);
addr += size;
db_printf("%-*ly", width, (long)value);
break;
case 'd': /* signed decimal */
value = db_get_value(addr, size, true);
addr += size;
db_printf("%-*ld", width, (long)value);
break;
case 'u': /* unsigned decimal */
value = db_get_value(addr, size, false);
addr += size;
db_printf("%-*lu", width, (long)value);
break;
case 'o': /* unsigned octal */
value = db_get_value(addr, size, false);
addr += size;
db_printf("%-*lo", width, (long)value);
break;
case 'c': /* character */
value = db_get_value(addr, 1, false);
addr += 1;
if (value >= ' ' && value <= '~')
db_printf("%c", (int)value);
else
db_printf("\\%03o", (int)value);
break;
case 's': /* null-terminated string */
for (;;) {
value = db_get_value(addr, 1, false);
addr += 1;
if (value == 0)
break;
if (value >= ' ' && value <= '~')
db_printf("%c", (int)value);
else
db_printf("\\%03o", (int)value);
}
break;
case 'S': /* symbol */
value = db_get_value(addr, sizeof(void *),
false);
addr += sizeof(void *);
db_printsym(value, DB_STGY_ANY);
break;
case 'i': /* instruction */
addr = db_disasm(addr, false);
break;
case 'I': /* instruction, alternate form */
addr = db_disasm(addr, true);
break;
default:
break;
}
if (db_print_position() != 0)
db_end_line(1);
break;
}
}
}
db_next = addr;
}
/*
* Print value.
*/
static char db_print_format = 'x';
/*ARGSUSED*/
void
db_print_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
{
db_expr_t value;
if (modif[0] != '\0')
db_print_format = modif[0];
switch (db_print_format) {
case 'a':
db_printsym((db_addr_t)addr, DB_STGY_ANY);
break;
case 'r':
db_printf("%+11lr", (long)addr);
break;
case 'x':
db_printf("%8lx", (unsigned long)addr);
break;
case 'z':
db_printf("%8ly", (long)addr);
break;
case 'd':
db_printf("%11ld", (long)addr);
break;
case 'u':
db_printf("%11lu", (unsigned long)addr);
break;
case 'o':
db_printf("%16lo", (unsigned long)addr);
break;
case 'c':
value = addr & 0xFF;
if (value >= ' ' && value <= '~')
db_printf("%c", (int)value);
else
db_printf("\\%03o", (int)value);
break;
}
db_printf("\n");
}
void
db_print_loc_and_inst(db_addr_t loc)
{
db_expr_t off;
db_printsym(loc, DB_STGY_PROC);
if (db_search_symbol(loc, DB_STGY_PROC, &off) != C_DB_SYM_NULL) {
db_printf(":\t");
(void)db_disasm(loc, true);
}
}
/*
* Search for a value in memory.
* Syntax: search [/bhl] addr value [mask] [,count]
*/
void
db_search_cmd(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
{
int t;
db_addr_t addr;
int size;
db_expr_t value;
db_expr_t mask;
db_expr_t count;
t = db_read_token();
if (t == tSLASH) {
t = db_read_token();
if (t != tIDENT) {
bad_modifier:
db_printf("Bad modifier\n");
db_flush_lex();
return;
}
if (!strcmp(db_tok_string, "b"))
size = 1;
else if (!strcmp(db_tok_string, "h"))
size = 2;
else if (!strcmp(db_tok_string, "l"))
size = 4;
else
goto bad_modifier;
} else {
db_unread_token(t);
size = 4;
}
if (!db_expression((db_expr_t *)&addr)) {
db_printf("Address missing\n");
db_flush_lex();
return;
}
if (!db_expression(&value)) {
db_printf("Value missing\n");
db_flush_lex();
return;
}
if (!db_expression(&mask))
mask = 0xffffffffUL;
t = db_read_token();
if (t == tCOMMA) {
if (!db_expression(&count)) {
db_printf("Count missing\n");
db_flush_lex();
return;
}
} else {
db_unread_token(t);
count = -1; /* effectively forever */
}
db_skip_to_eol();
db_search(addr, size, value, mask, count);
}
static void
db_search(db_addr_t addr, int size, db_expr_t value, db_expr_t mask,
unsigned int count)
{
while (count-- != 0) {
db_prev = addr;
if ((db_get_value(addr, size, false) & mask) == value)
break;
addr += size;
}
db_next = addr;
}