freebsd-skq/sys/ddb/db_command.c
Dima Dorfman 19d2c78f34 Implement a "kill" DDB command which is an interface to psignal() that
respects locks.  Before SMPng, one was able to call psignal()
using the "call" command, but this is no longer possible because it
does not respect locks by itself.  This is very useful when one has
gotten their machine into a state where it is impossible to spawn
ps/kill or su to root.

In this case, respecting locks essentially means trying to aquire the
proc lock before calling psignal().  We can't block in the debugger,
so if trylock fails, the operation fails.  This also means that we
can't use pfind(), since that will attempt to lock the process for us.

Reviewed by:	jhb
2001-11-27 19:56:28 +00:00

645 lines
14 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.
*
* $FreeBSD$
*/
/*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
/*
* Command dispatcher.
*/
#include <sys/param.h>
#include <sys/linker_set.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/cons.h>
#include <ddb/ddb.h>
#include <ddb/db_command.h>
#include <ddb/db_lex.h>
#include <ddb/db_output.h>
#include <machine/md_var.h>
#include <machine/setjmp.h>
/*
* Exported global variables
*/
boolean_t db_cmd_loop_done;
db_addr_t db_dot;
jmp_buf db_jmpbuf;
db_addr_t db_last_addr;
db_addr_t db_prev;
db_addr_t db_next;
SET_DECLARE(db_cmd_set, struct command);
SET_DECLARE(db_show_cmd_set, struct command);
static db_cmdfcn_t db_fncall;
static db_cmdfcn_t db_gdb;
static db_cmdfcn_t db_kill;
static db_cmdfcn_t db_reset;
/* XXX this is actually forward-static. */
extern struct command db_show_cmds[];
/*
* if 'ed' style: 'dot' is set at start of last item printed,
* and '+' points to next line.
* Otherwise: 'dot' points to next item, '..' points to last.
*/
static boolean_t db_ed_style = TRUE;
/*
* Utility routine - discard tokens through end-of-line.
*/
void
db_skip_to_eol()
{
int t;
do {
t = db_read_token();
} while (t != tEOL);
}
/*
* Results of command search.
*/
#define CMD_UNIQUE 0
#define CMD_FOUND 1
#define CMD_NONE 2
#define CMD_AMBIGUOUS 3
#define CMD_HELP 4
static void db_cmd_list __P((struct command *table,
struct command **aux_tablep,
struct command **aux_tablep_end));
static int db_cmd_search __P((char *name, struct command *table,
struct command **aux_tablep,
struct command **aux_tablep_end,
struct command **cmdp));
static void db_command __P((struct command **last_cmdp,
struct command *cmd_table,
struct command **aux_cmd_tablep,
struct command **aux_cmd_tablep_end));
/*
* Search for command prefix.
*/
static int
db_cmd_search(name, table, aux_tablep, aux_tablep_end, cmdp)
char * name;
struct command *table;
struct command **aux_tablep;
struct command **aux_tablep_end;
struct command **cmdp; /* out */
{
struct command *cmd;
struct command **aux_cmdp;
int result = CMD_NONE;
for (cmd = table; cmd->name != 0; cmd++) {
register char *lp;
register char *rp;
register int c;
lp = name;
rp = cmd->name;
while ((c = *lp) == *rp) {
if (c == 0) {
/* complete match */
*cmdp = cmd;
return (CMD_UNIQUE);
}
lp++;
rp++;
}
if (c == 0) {
/* end of name, not end of command -
partial match */
if (result == CMD_FOUND) {
result = CMD_AMBIGUOUS;
/* but keep looking for a full match -
this lets us match single letters */
}
else {
*cmdp = cmd;
result = CMD_FOUND;
}
}
}
if (result == CMD_NONE && aux_tablep != 0)
/* XXX repeat too much code. */
for (aux_cmdp = aux_tablep; aux_cmdp < aux_tablep_end; aux_cmdp++) {
register char *lp;
register char *rp;
register int c;
lp = name;
rp = (*aux_cmdp)->name;
while ((c = *lp) == *rp) {
if (c == 0) {
/* complete match */
*cmdp = *aux_cmdp;
return (CMD_UNIQUE);
}
lp++;
rp++;
}
if (c == 0) {
/* end of name, not end of command -
partial match */
if (result == CMD_FOUND) {
result = CMD_AMBIGUOUS;
/* but keep looking for a full match -
this lets us match single letters */
}
else {
*cmdp = *aux_cmdp;
result = CMD_FOUND;
}
}
}
if (result == CMD_NONE) {
/* check for 'help' */
if (name[0] == 'h' && name[1] == 'e'
&& name[2] == 'l' && name[3] == 'p')
result = CMD_HELP;
}
return (result);
}
static void
db_cmd_list(table, aux_tablep, aux_tablep_end)
struct command *table;
struct command **aux_tablep;
struct command **aux_tablep_end;
{
register struct command *cmd;
register struct command **aux_cmdp;
for (cmd = table; cmd->name != 0; cmd++) {
db_printf("%-12s", cmd->name);
db_end_line();
}
if (aux_tablep == 0)
return;
for (aux_cmdp = aux_tablep; aux_cmdp < aux_tablep_end; aux_cmdp++) {
db_printf("%-12s", (*aux_cmdp)->name);
db_end_line();
}
}
static void
db_command(last_cmdp, cmd_table, aux_cmd_tablep, aux_cmd_tablep_end)
struct command **last_cmdp; /* IN_OUT */
struct command *cmd_table;
struct command **aux_cmd_tablep;
struct command **aux_cmd_tablep_end;
{
struct command *cmd;
int t;
char modif[TOK_STRING_SIZE];
db_expr_t addr, count;
boolean_t have_addr = FALSE;
int result;
t = db_read_token();
if (t == tEOL) {
/* empty line repeats last command, at 'next' */
cmd = *last_cmdp;
addr = (db_expr_t)db_next;
have_addr = FALSE;
count = 1;
modif[0] = '\0';
}
else if (t == tEXCL) {
db_fncall((db_expr_t)0, (boolean_t)0, (db_expr_t)0, (char *)0);
return;
}
else if (t != tIDENT) {
db_printf("?\n");
db_flush_lex();
return;
}
else {
/*
* Search for command
*/
while (cmd_table) {
result = db_cmd_search(db_tok_string,
cmd_table,
aux_cmd_tablep,
aux_cmd_tablep_end,
&cmd);
switch (result) {
case CMD_NONE:
db_printf("No such command\n");
db_flush_lex();
return;
case CMD_AMBIGUOUS:
db_printf("Ambiguous\n");
db_flush_lex();
return;
case CMD_HELP:
db_cmd_list(cmd_table, aux_cmd_tablep, aux_cmd_tablep_end);
db_flush_lex();
return;
default:
break;
}
if ((cmd_table = cmd->more) != 0) {
/* XXX usually no more aux's. */
aux_cmd_tablep = 0;
if (cmd_table == db_show_cmds)
aux_cmd_tablep = SET_BEGIN(db_show_cmd_set);
aux_cmd_tablep_end = SET_LIMIT(db_show_cmd_set);
t = db_read_token();
if (t != tIDENT) {
db_cmd_list(cmd_table, aux_cmd_tablep, aux_cmd_tablep_end);
db_flush_lex();
return;
}
}
}
if ((cmd->flag & CS_OWN) == 0) {
/*
* Standard syntax:
* command [/modifier] [addr] [,count]
*/
t = db_read_token();
if (t == tSLASH) {
t = db_read_token();
if (t != tIDENT) {
db_printf("Bad modifier\n");
db_flush_lex();
return;
}
db_strcpy(modif, db_tok_string);
}
else {
db_unread_token(t);
modif[0] = '\0';
}
if (db_expression(&addr)) {
db_dot = (db_addr_t) addr;
db_last_addr = db_dot;
have_addr = TRUE;
}
else {
addr = (db_expr_t) db_dot;
have_addr = FALSE;
}
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;
}
if ((cmd->flag & CS_MORE) == 0) {
db_skip_to_eol();
}
}
}
*last_cmdp = cmd;
if (cmd != 0) {
/*
* Execute the command.
*/
(*cmd->fcn)(addr, have_addr, count, modif);
if (cmd->flag & CS_SET_DOT) {
/*
* If command changes dot, set dot to
* previous address displayed (if 'ed' style).
*/
if (db_ed_style) {
db_dot = db_prev;
}
else {
db_dot = db_next;
}
}
else {
/*
* If command does not change dot,
* set 'next' location to be the same.
*/
db_next = db_dot;
}
}
}
/*
* 'show' commands
*/
static struct command db_show_all_cmds[] = {
#if 0
{ "threads", db_show_all_threads, 0, 0 },
#endif
{ "procs", db_ps, 0, 0 },
{ (char *)0 }
};
static struct command db_show_cmds[] = {
{ "all", 0, 0, db_show_all_cmds },
{ "registers", db_show_regs, 0, 0 },
{ "breaks", db_listbreak_cmd, 0, 0 },
#if 0
{ "thread", db_show_one_thread, 0, 0 },
#endif
#if 0
{ "port", ipc_port_print, 0, 0 },
#endif
{ (char *)0, }
};
static struct command db_command_table[] = {
{ "print", db_print_cmd, 0, 0 },
{ "p", db_print_cmd, 0, 0 },
{ "examine", db_examine_cmd, CS_SET_DOT, 0 },
{ "x", db_examine_cmd, CS_SET_DOT, 0 },
{ "search", db_search_cmd, CS_OWN|CS_SET_DOT, 0 },
{ "set", db_set_cmd, CS_OWN, 0 },
{ "write", db_write_cmd, CS_MORE|CS_SET_DOT, 0 },
{ "w", db_write_cmd, CS_MORE|CS_SET_DOT, 0 },
{ "delete", db_delete_cmd, 0, 0 },
{ "d", db_delete_cmd, 0, 0 },
{ "break", db_breakpoint_cmd, 0, 0 },
{ "dwatch", db_deletewatch_cmd, 0, 0 },
{ "watch", db_watchpoint_cmd, CS_MORE,0 },
{ "dhwatch", db_deletehwatch_cmd, 0, 0 },
{ "hwatch", db_hwatchpoint_cmd, 0, 0 },
{ "step", db_single_step_cmd, 0, 0 },
{ "s", db_single_step_cmd, 0, 0 },
{ "continue", db_continue_cmd, 0, 0 },
{ "c", db_continue_cmd, 0, 0 },
{ "until", db_trace_until_call_cmd,0, 0 },
{ "next", db_trace_until_matching_cmd,0, 0 },
{ "match", db_trace_until_matching_cmd,0, 0 },
{ "trace", db_stack_trace_cmd, 0, 0 },
{ "call", db_fncall, CS_OWN, 0 },
{ "show", 0, 0, db_show_cmds },
{ "ps", db_ps, 0, 0 },
{ "gdb", db_gdb, 0, 0 },
{ "reset", db_reset, 0, 0 },
{ "kill", db_kill, CS_OWN, 0 },
{ (char *)0, }
};
static struct command *db_last_command = 0;
#if 0
void
db_help_cmd()
{
struct command *cmd = db_command_table;
while (cmd->name != 0) {
db_printf("%-12s", cmd->name);
db_end_line();
cmd++;
}
}
#endif
/*
* At least one non-optional command must be implemented using
* DB_COMMAND() so that db_cmd_set gets created. Here is one.
*/
DB_COMMAND(panic, db_panic)
{
panic("from debugger");
}
void
db_command_loop()
{
/*
* Initialize 'prev' and 'next' to dot.
*/
db_prev = db_dot;
db_next = db_dot;
db_cmd_loop_done = 0;
while (!db_cmd_loop_done) {
(void) setjmp(db_jmpbuf);
if (db_print_position() != 0)
db_printf("\n");
db_printf("db> ");
(void) db_read_line();
db_command(&db_last_command, db_command_table,
SET_BEGIN(db_cmd_set), SET_LIMIT(db_cmd_set));
}
}
void
db_error(s)
char *s;
{
if (s)
db_printf("%s", s);
db_flush_lex();
longjmp(db_jmpbuf, 1);
}
/*
* Call random function:
* !expr(arg,arg,arg)
*/
static void
db_fncall(dummy1, dummy2, dummy3, dummy4)
db_expr_t dummy1;
boolean_t dummy2;
db_expr_t dummy3;
char * dummy4;
{
db_expr_t fn_addr;
#define MAXARGS 11 /* XXX only 10 are passed */
db_expr_t args[MAXARGS];
int nargs = 0;
db_expr_t retval;
typedef db_expr_t fcn_10args_t __P((db_expr_t, db_expr_t, db_expr_t,
db_expr_t, db_expr_t, db_expr_t,
db_expr_t, db_expr_t, db_expr_t,
db_expr_t));
fcn_10args_t *func;
int t;
if (!db_expression(&fn_addr)) {
db_printf("Bad function\n");
db_flush_lex();
return;
}
func = (fcn_10args_t *)fn_addr; /* XXX */
t = db_read_token();
if (t == tLPAREN) {
if (db_expression(&args[0])) {
nargs++;
while ((t = db_read_token()) == tCOMMA) {
if (nargs == MAXARGS) {
db_printf("Too many arguments\n");
db_flush_lex();
return;
}
if (!db_expression(&args[nargs])) {
db_printf("Argument missing\n");
db_flush_lex();
return;
}
nargs++;
}
db_unread_token(t);
}
if (db_read_token() != tRPAREN) {
db_printf("?\n");
db_flush_lex();
return;
}
}
db_skip_to_eol();
while (nargs < MAXARGS) {
args[nargs++] = 0;
}
retval = (*func)(args[0], args[1], args[2], args[3], args[4],
args[5], args[6], args[7], args[8], args[9] );
db_printf("%#lr\n", (long)retval);
}
/* Enter GDB remote protocol debugger on the next trap. */
dev_t gdbdev = NODEV;
cn_getc_t *gdb_getc;
cn_putc_t *gdb_putc;
static void
db_gdb (dummy1, dummy2, dummy3, dummy4)
db_expr_t dummy1;
boolean_t dummy2;
db_expr_t dummy3;
char * dummy4;
{
if (gdbdev == NODEV) {
db_printf("No gdb port enabled. Set flag 0x80 on desired port\n");
db_printf("in your configuration file (currently sio only).\n");
return;
}
boothowto ^= RB_GDB;
db_printf("Next trap will enter %s\n",
boothowto & RB_GDB ? "GDB remote protocol mode"
: "DDB debugger");
}
static void
db_kill(dummy1, dummy2, dummy3, dummy4)
db_expr_t dummy1;
boolean_t dummy2;
db_expr_t dummy3;
char * dummy4;
{
db_expr_t old_radix, pid, sig;
struct proc *p;
#define DB_ERROR(f) do { db_printf f; db_flush_lex(); goto out; } while (0)
/*
* PIDs and signal numbers are typically represented in base
* 10, so make that the default here. It can, of course, be
* overridden by specifying a prefix.
*/
old_radix = db_radix;
db_radix = 10;
/* Retrieve arguments. */
if (!db_expression(&sig))
DB_ERROR(("Missing signal number\n"));
if (!db_expression(&pid))
DB_ERROR(("Missing process ID\n"));
db_skip_to_eol();
if (sig < 0 || sig > _SIG_MAXSIG)
DB_ERROR(("Signal number out of range\n"));
/*
* Find the process in question. allproc_lock is not needed
* since we're in DDB.
*/
/* sx_slock(&allproc_lock); */
LIST_FOREACH(p, &allproc, p_list)
if (p->p_pid == pid)
break;
/* sx_sunlock(&allproc_lock); */
if (p == NULL)
DB_ERROR(("Can't find process with pid %d\n", pid));
/* If it's already locked, bail; otherwise, do the deed. */
if (PROC_TRYLOCK(p) == 0)
DB_ERROR(("Can't lock process with pid %d\n", pid));
else {
psignal(p, sig);
PROC_UNLOCK(p);
}
out:
db_radix = old_radix;
#undef DB_ERROR
}
static void
db_reset(dummy1, dummy2, dummy3, dummy4)
db_expr_t dummy1;
boolean_t dummy2;
db_expr_t dummy3;
char * dummy4;
{
cpu_reset();
}