kern/127265: [patch] Adding the ddb command set from modules
Guillaume Ballet
gballet at gmail.com
Wed Sep 10 07:40:02 UTC 2008
>Number: 127265
>Category: kern
>Synopsis: [patch] Adding the ddb command set from modules
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Wed Sep 10 07:40:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator: Guillaume Ballet
>Release: 7.0-RELEASE
>Organization:
>Environment:
FreeBSD 7.0-RELEASE FreeBSD 7.0-RELEASE #37: Sat Aug 23 21:59:19 CEST 2008 root@:/usr/src/sys/i386/compile/HAMMERHEAD i386
>Description:
It is possible to use DB_COMMAND to add commands to ddb from the kernel. Using DB_COMMAND from a kernel module, however, is not working. I have altered the ddb code to do so.
>How-To-Repeat:
Create a module and use DB_COMMAND (example below). Then drop inside ddb. Nothing happens.
DB_COMMAND(mycmd, my_cmd_func)
{
if (have_addr)
db_printf("Calling my command with address %p\n", addr);
}
>Fix:
The patch is provided as an attachment. I have also written a man page, because I found out that DB_COMMAND was undocumented. The text for the man page is pasted hereafter:
.Dd August 27, 2008
.Dt DB_COMMAND 9
.Os
.Sh NAME
.Nm DB_COMMAND ,
.Nm DB_SHOW_COMMAND ,
.Nm DB_SHOW_ALL_COMMAND
.Nd Extends the ddb command set.
.Sh SYNOPSIS
.In ddb/ddb.h
.Fo DB_COMMAND
.Fa command_name
.Fa command_function
.Fc
.Fn DB_SHOW_COMMAND "command_name" "command_function"
.Fn DB_SHOW_ALL_COMMAND "command_name" "command_function"
.Sh DESCRIPTION
.Pp
The
.Fn DB_COMMAND
macro adds
.Fa command_name
to the list of top-level commands. Invoking
.Fa command_name
from ddb will call
.Fa command_function .
.Pp
The
.Fn DB_SHOW_COMMAND
and
.Fn DB_SHOW_ALL_COMMAND
are roughly equivalent to
.Fn DB_COMMAND
but in these cases,
.Fa command_name
is a sub-command of the ddb
.Sy show
command and
.Sy show all
command, respectively.
.Pp
The general command syntax:
.Cm command Ns Op Li \&/ Ns Ar modifier
.Ar address Ns Op Li , Ns Ar count ,
translates into the following parameters for
.Fa command_function :
.Bl -tag
.It Fa addr
The address passed to the command as an argument.
.It Fa have_addr
A boolean value that is true if the addr field is valid.
.It Fa count
The number of quad words starting at offset
.Fa addr
that the command must process.
.It Fa modif
A pointer to the string of modifiers. That is, a series of symbols used to pass some options to the command. For example, the
.Sy examine
command will display words in decimal form if it is passed the modifier "d".
.El
.Sh EXAMPLE
In your module, the command is declared as:
.Pp
.Bd -literal
DB_COMMAND(mycmd, my_cmd_func)
{
if (have_addr)
db_printf("Calling my command with address %p\\n", addr);
}
.Ed
.Pp
Then, when in ddb:
.Pp
.Bd -literal
.Bf Sy
db> mycmd 0x1000
Calling my command with address 0x1000
db>
.Ef
.Ed
.Sh "SEE ALSO"
.Xr ddb 4
.Sh AUTHOR
This manual page was written by
.An Guillaume Ballet Aq gballet at gmail.com .
Patch attached with submission follows:
--- ./ddb/db_command.c.orig 2008-08-19 00:56:41.000000000 +0200
+++ ./ddb/db_command.c 2008-08-24 20:59:41.000000000 +0200
@@ -45,6 +45,7 @@
#include <sys/systm.h>
#include <sys/cons.h>
#include <sys/watchdog.h>
+#include <sys/kernel.h>
#include <ddb/ddb.h>
#include <ddb/db_command.h>
@@ -76,78 +77,68 @@
static db_cmdfcn_t db_watchdog;
/*
+ * Array containing all command 'tables'. See ddb.h.
+ */
+static struct command_table db_command_tables[DB_COMMAND_TABLES_SIZE] = {
+ STAILQ_HEAD_INITIALIZER(db_command_tables[DB_COMMAND_TABLES_DEFAULT]),
+ STAILQ_HEAD_INITIALIZER(db_command_tables[DB_COMMAND_TABLES_SHOW]),
+ STAILQ_HEAD_INITIALIZER(db_command_tables[DB_COMMAND_TABLES_SHOW_ALL])
+};
+
+/*
* 'show' commands
*/
static struct command db_show_all_cmds[] = {
- { "procs", db_ps, 0, 0 },
- { (char *)0 }
-};
-
-static struct command_table db_show_all_table = {
- db_show_all_cmds
+ { { NULL }, "procs", db_ps, 0, 0 }
};
static struct command db_show_cmds[] = {
- { "all", 0, 0, &db_show_all_table },
- { "registers", db_show_regs, 0, 0 },
- { "breaks", db_listbreak_cmd, 0, 0 },
- { "threads", db_show_threads, 0, 0 },
- { (char *)0, }
+ { { NULL }, "all", 0, 0, &db_command_tables[DB_COMMAND_TABLES_SHOW_ALL] },
+ { { NULL }, "registers", db_show_regs, 0, 0 },
+ { { NULL }, "breaks", db_listbreak_cmd, 0, 0 },
+ { { NULL }, "threads", db_show_threads, 0, 0 }
};
-static struct command_table db_show_table = {
- db_show_cmds,
- SET_BEGIN(db_show_cmd_set),
- SET_LIMIT(db_show_cmd_set)
-};
-
static struct command db_commands[] = {
- { "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 },
- { "b", 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, CS_OWN, 0 },
- { "t", db_stack_trace, CS_OWN, 0 },
- { "alltrace", db_stack_trace_all, 0, 0 },
- { "where", db_stack_trace, CS_OWN, 0 },
- { "bt", db_stack_trace, CS_OWN, 0 },
- { "call", db_fncall, CS_OWN, 0 },
- { "show", 0, 0, &db_show_table },
- { "ps", db_ps, 0, 0 },
- { "gdb", db_gdb, 0, 0 },
- { "halt", db_halt, 0, 0 },
- { "reboot", db_reset, 0, 0 },
- { "reset", db_reset, 0, 0 },
- { "kill", db_kill, CS_OWN, 0 },
- { "watchdog", db_watchdog, 0, 0 },
- { "thread", db_set_thread, CS_OWN, 0 },
- { (char *)0, }
-};
-
-static struct command_table db_command_table = {
- db_commands,
- SET_BEGIN(db_cmd_set),
- SET_LIMIT(db_cmd_set)
+ { { NULL }, "print", db_print_cmd, 0, 0 },
+ { { NULL }, "p", db_print_cmd, 0, 0 },
+ { { NULL }, "examine", db_examine_cmd, CS_SET_DOT, 0 },
+ { { NULL }, "x", db_examine_cmd, CS_SET_DOT, 0 },
+ { { NULL }, "search", db_search_cmd, CS_OWN|CS_SET_DOT, 0 },
+ { { NULL }, "set", db_set_cmd, CS_OWN, 0 },
+ { { NULL }, "write", db_write_cmd, CS_MORE|CS_SET_DOT, 0 },
+ { { NULL }, "w", db_write_cmd, CS_MORE|CS_SET_DOT, 0 },
+ { { NULL }, "delete", db_delete_cmd, 0, 0 },
+ { { NULL }, "d", db_delete_cmd, 0, 0 },
+ { { NULL }, "break", db_breakpoint_cmd, 0, 0 },
+ { { NULL }, "b", db_breakpoint_cmd, 0, 0 },
+ { { NULL }, "dwatch", db_deletewatch_cmd, 0, 0 },
+ { { NULL }, "watch", db_watchpoint_cmd, CS_MORE,0 },
+ { { NULL }, "dhwatch", db_deletehwatch_cmd, 0, 0 },
+ { { NULL }, "hwatch", db_hwatchpoint_cmd, 0, 0 },
+ { { NULL }, "step", db_single_step_cmd, 0, 0 },
+ { { NULL }, "s", db_single_step_cmd, 0, 0 },
+ { { NULL }, "continue", db_continue_cmd, 0, 0 },
+ { { NULL }, "c", db_continue_cmd, 0, 0 },
+ { { NULL }, "until", db_trace_until_call_cmd,0, 0 },
+ { { NULL }, "next", db_trace_until_matching_cmd,0, 0 },
+ { { NULL }, "match", db_trace_until_matching_cmd,0, 0 },
+ { { NULL }, "trace", db_stack_trace, CS_OWN, 0 },
+ { { NULL }, "t", db_stack_trace, CS_OWN, 0 },
+ { { NULL }, "alltrace", db_stack_trace_all, 0, 0 },
+ { { NULL }, "where", db_stack_trace, CS_OWN, 0 },
+ { { NULL }, "bt", db_stack_trace, CS_OWN, 0 },
+ { { NULL }, "call", db_fncall, CS_OWN, 0 },
+ { { NULL }, "show", 0, 0, &db_command_tables[DB_COMMAND_TABLES_SHOW] },
+ { { NULL }, "ps", db_ps, 0, 0 },
+ { { NULL }, "gdb", db_gdb, 0, 0 },
+ { { NULL }, "halt", db_halt, 0, 0 },
+ { { NULL }, "reboot", db_reset, 0, 0 },
+ { { NULL }, "reset", db_reset, 0, 0 },
+ { { NULL }, "kill", db_kill, CS_OWN, 0 },
+ { { NULL }, "watchdog", db_watchdog, 0, 0 },
+ { { NULL }, "thread", db_set_thread, CS_OWN, 0 }
};
static struct command *db_last_command = 0;
@@ -189,6 +180,73 @@
struct command_table *cmd_table);
/*
+ * Initialize command tables using the commands declared above.
+ */
+void
+db_cmd_init()
+{
+ int cnt;
+
+ for (cnt=0; cnt<(sizeof(db_commands) / sizeof(struct command)); cnt++)
+ STAILQ_INSERT_TAIL(&db_command_tables[DB_COMMAND_TABLES_DEFAULT],
+ &(db_commands[cnt]),
+ next);
+ for (cnt=0; cnt<(sizeof(db_show_cmds) / sizeof(struct command)); cnt++)
+ STAILQ_INSERT_TAIL(&db_command_tables[DB_COMMAND_TABLES_SHOW],
+ &(db_show_cmds[cnt]),
+ next);
+ for (cnt=0; cnt<(sizeof(db_show_all_cmds) / sizeof(struct command)); cnt++)
+ STAILQ_INSERT_TAIL(&db_command_tables[DB_COMMAND_TABLES_SHOW_ALL],
+ &(db_show_all_cmds[cnt]),
+ next);
+}
+
+/*
+ * Called by modules through SYSINIT to extend the command set.
+ */
+void db_command_register(list_index, cmd)
+ int list_index;
+ struct command *cmd;
+{
+ if (list_index >= DB_COMMAND_TABLES_SIZE)
+ panic("Attempting to add a debugger command to an invalid list!");
+
+#if 0
+ /* Check that the command is not already present. */
+ struct command *scmd;
+ STAILQ_FOREACH(scmd, &(db_command_tables[list_index]), next) {
+ if (!strcmp(cmd->name, scmd->name))
+ panic("The command %s already exists!", cmd->name);
+ }
+#endif
+
+ if (cmd != NULL) {
+ STAILQ_INSERT_TAIL(&(db_command_tables[list_index]),
+ cmd, next);
+ }
+}
+
+/*
+ * Called by SYSUNINIT. Revert what has been done above.
+ */
+void db_command_unregister(table_index, command_name)
+ int table_index;
+ char *command_name;
+{
+ struct command *cmd;
+
+ STAILQ_FOREACH(cmd, &(db_command_tables[table_index]), next) {
+ if (!strcmp(command_name,cmd->name)) {
+ STAILQ_REMOVE(&(db_command_tables[table_index]),
+ cmd,
+ command,
+ next);
+ break;
+ }
+ }
+}
+
+/*
* Helper function to match a single command.
*/
static void
@@ -236,23 +294,15 @@
struct command_table *table;
struct command **cmdp; /* out */
{
- struct command *cmd;
- struct command **aux_cmdp;
- int result = CMD_NONE;
+ struct command *cmd;
+ int result = CMD_NONE;
- for (cmd = table->table; cmd->name != 0; cmd++) {
- db_cmd_match(name, cmd, cmdp, &result);
+ STAILQ_FOREACH(cmd,table,next) {
+ db_cmd_match(name,cmd,cmdp,&result);
if (result == CMD_UNIQUE)
- return (CMD_UNIQUE);
+ break;
}
- if (table->aux_tablep != NULL)
- for (aux_cmdp = table->aux_tablep;
- aux_cmdp < table->aux_tablep_end;
- aux_cmdp++) {
- db_cmd_match(name, *aux_cmdp, cmdp, &result);
- if (result == CMD_UNIQUE)
- return (CMD_UNIQUE);
- }
+
if (result == CMD_NONE) {
/* check for 'help' */
if (name[0] == 'h' && name[1] == 'e'
@@ -266,19 +316,11 @@
db_cmd_list(table)
struct command_table *table;
{
- register struct command *cmd;
- register struct command **aux_cmdp;
+ register struct command *cmd;
- for (cmd = table->table; cmd->name != 0; cmd++) {
- db_printf("%-12s", cmd->name);
- db_end_line(12);
- }
- if (table->aux_tablep == NULL)
- return;
- for (aux_cmdp = table->aux_tablep; aux_cmdp < table->aux_tablep_end;
- aux_cmdp++) {
- db_printf("%-12s", (*aux_cmdp)->name);
- db_end_line(12);
+ STAILQ_FOREACH(cmd, table, next) {
+ db_printf("%-12s", cmd->name);
+ db_end_line(12);
}
}
@@ -287,7 +329,7 @@
struct command **last_cmdp; /* IN_OUT */
struct command_table *cmd_table;
{
- struct command *cmd;
+ struct command *cmd = NULL;
int t;
char modif[TOK_STRING_SIZE];
db_expr_t addr, count;
@@ -450,7 +492,7 @@
db_printf("db> ");
(void) db_read_line();
- db_command(&db_last_command, &db_command_table);
+ db_command(&db_last_command, &(db_command_tables[DB_COMMAND_TABLES_DEFAULT]));
}
}
--- ./ddb/ddb.h.orig 2008-08-19 01:04:24.000000000 +0200
+++ ./ddb/ddb.h 2008-08-23 21:53:28.000000000 +0200
@@ -39,6 +39,9 @@
#include <machine/db_machdep.h> /* type definitions */
+#include <sys/queue.h> /* STAILQ_* */
+#include <sys/kernel.h> /* SYSINIT */
+
#ifndef DB_MAXARGS
#define DB_MAXARGS 10
#endif
@@ -53,23 +56,38 @@
char *modif);
#define DB_COMMAND(cmd_name, func_name) \
- DB_FUNC(cmd_name, func_name, db_cmd_set, 0, NULL)
+ DB_FUNC(cmd_name, func_name, DB_COMMAND_TABLES_DEFAULT, 0, NULL)
#define DB_SHOW_COMMAND(cmd_name, func_name) \
- DB_FUNC(cmd_name, func_name, db_show_cmd_set, 0, NULL)
+ DB_FUNC(cmd_name, func_name, DB_COMMAND_TABLES_SHOW, 0, NULL)
+#define DB_SHOW_ALL_COMMAND(cmd_name, func_name) \
+ DB_FUNC(cmd_name, func_name, DB_COMMAND_TABLES_SHOW_ALL, 0, NULL)
-#define DB_SET(cmd_name, func_name, set, flag, more) \
-static const struct command __CONCAT(cmd_name,_cmd) = { \
- __STRING(cmd_name), \
- func_name, \
- flag, \
- more \
-}; \
-TEXT_SET(set, __CONCAT(cmd_name,_cmd))
+/*
+ * At the moment, there are three command "tables" on the system:
+ * - One for simple commands, whose list one can get by typing 'help'
+ * at debugger prompt.
+ * - One for sub-commands of 'show'.
+ * - The last one for sub-commands of 'show all'.
+ * All these tables are stored in an array, and the constants defined
+ * hereafter give the offset in the array at which the head for each
+ * table can be found.
+ */
+enum {
+ DB_COMMAND_TABLES_DEFAULT,
+ DB_COMMAND_TABLES_SHOW,
+ DB_COMMAND_TABLES_SHOW_ALL,
+ DB_COMMAND_TABLES_SIZE
+};
+
+struct command;
-#define DB_FUNC(cmd_name, func_name, set, flag, more) \
+/*
+ * Declare the function func_name, which is handling db command
+ * cmd_name)
+ */
+#define DB_FUNC(cmd_name, func_name, list, flag, more) \
static db_cmdfcn_t func_name; \
- \
-DB_SET(cmd_name, func_name, set, flag, more); \
+DB_SET(cmd_name, func_name, list, flag, more); \
\
static void \
func_name(addr, have_addr, count, modif) \
@@ -78,6 +96,35 @@
db_expr_t count; \
char *modif;
+/*
+ * Add command 'cmd_name' to the command table, along
+ * with the SYSINIT functions to load and unload it.
+ */
+#define DB_SET(cmd_name, func_name, list, flag, more) \
+static struct command __CONCAT(cmd_name,_cmd) = { \
+ { NULL }, \
+ __STRING(cmd_name), \
+ func_name, \
+ flag, \
+ more \
+}; \
+ \
+static void __CONCAT(cmd_name,_db_cmd_add)(void*); \
+static void __CONCAT(cmd_name,_db_cmd_rm)(void*); \
+ \
+static void __CONCAT(cmd_name,_db_cmd_add)(void *arg __unused) \
+{ \
+ db_command_register(list, &__CONCAT(cmd_name,_cmd)); \
+} \
+ \
+static void __CONCAT(cmd_name,_db_cmd_rm)(void *arg __unused) \
+{ \
+ db_command_unregister(list,__STRING(cmd_name)); \
+} \
+ \
+SYSINIT(cmd_name, SI_SUB_KLD, SI_ORDER_ANY, __CONCAT(cmd_name,_db_cmd_add), NULL); \
+SYSUNINIT(cmd_name, SI_SUB_KLD, SI_ORDER_ANY, __CONCAT(cmd_name,_db_cmd_rm), NULL);
+
extern db_expr_t db_maxoff;
extern int db_indent;
extern int db_inst_count;
@@ -124,6 +171,9 @@
int db_trace_thread(struct thread *, int);
int db_value_of_name(const char *name, db_expr_t *valuep);
int db_write_bytes(vm_offset_t addr, size_t size, char *data);
+void db_cmd_init(void);
+void db_command_register(int, struct command *);
+void db_command_unregister(int, char *);
db_cmdfcn_t db_breakpoint_cmd;
db_cmdfcn_t db_continue_cmd;
@@ -147,17 +197,17 @@
db_cmdfcn_t db_write_cmd;
/*
- * Command table.
+ * Declare command table type. It is actually a linked list, so
+ * as to allow for runtime extensions to the table.
*/
-struct command;
-
-struct command_table {
- struct command *table;
- struct command **aux_tablep;
- struct command **aux_tablep_end;
-};
+STAILQ_HEAD(command_table, command);
+/*
+ * Command table entry.
+ */
struct command {
+ STAILQ_ENTRY(command) /* Pointer to the next entry in the */
+ next; /* command table */
char * name; /* command name */
db_cmdfcn_t *fcn; /* function to call */
int flag; /* extra info: */
--- ./ddb/db_main.c.orig 2008-08-20 00:35:51.000000000 +0200
+++ ./ddb/db_main.c 2008-08-20 00:36:37.000000000 +0200
@@ -182,6 +182,8 @@
}
}
db_add_symbol_table(NULL, NULL, "kld", NULL);
+
+ db_cmd_init();
return (1); /* We're the default debugger. */
}
--- ./dev/aic7xxx/aic79xx_osm.c.orig 2008-08-21 02:42:04.000000000 +0200
+++ ./dev/aic7xxx/aic79xx_osm.c 2008-08-21 02:42:33.000000000 +0200
@@ -1423,7 +1423,7 @@
}
}
-DB_FUNC(ahd_out, ahd_ddb_out, db_cmd_set, CS_MORE, NULL)
+DB_FUNC(ahd_out, ahd_ddb_out, DB_COMMAND_TABLES_DEFAULT, CS_MORE, NULL)
{
db_expr_t old_value;
db_expr_t new_value;
--- ./gnu/fs/xfs/FreeBSD/support/kdb.c.orig 2008-08-24 16:47:00.000000000 +0200
+++ ./gnu/fs/xfs/FreeBSD/support/kdb.c 2008-08-24 16:47:30.000000000 +0200
@@ -12,7 +12,7 @@
#include <support/kdb.h>
#ifdef DDB
-DB_FUNC(xfs, xfs_ddb_cmd, db_cmd_set, CS_MORE, NULL)
+DB_FUNC(xfs, xfs_ddb_cmd, DB_COMMAND_TABLES_DEFAULT, CS_MORE, NULL)
{
db_error("No commands registered.\n");
}
--- ./kern/subr_sleepqueue.c.orig 2008-08-23 15:54:34.000000000 +0200
+++ ./kern/subr_sleepqueue.c 2008-08-21 21:49:13.000000000 +0200
@@ -983,5 +983,5 @@
}
/* Alias 'show sleepqueue' to 'show sleepq'. */
-DB_SET(sleepqueue, db_show_sleepqueue, db_show_cmd_set, 0, NULL);
+DB_SET(sleepqueue, db_show_sleepqueue, DB_COMMAND_TABLES_SHOW, 0, NULL);
#endif
>Release-Note:
>Audit-Trail:
>Unformatted:
More information about the freebsd-bugs
mailing list