Add the current command to the command information
[fw/openocd] / src / helper / command.c
index 0561c6c5bcbcb53a3e80bb870da64b6fe91649a1..e55f9e73e48682fbb331c7fc5514b846416cae86 100644 (file)
@@ -36,7 +36,7 @@
 #endif
 
 // @todo the inclusion of target.h here is a layering violation
-#include "target.h"
+#include <target/target.h>
 #include "command.h"
 #include "configuration.h"
 #include "log.h"
 #include "jim-eventloop.h"
 
 
-Jim_Interp *interp = NULL;
+/* nice short description of source file */
+#define __THIS__FILE__ "command.c"
+
 
 static int run_command(struct command_context *context,
                struct command *c, const char *words[], unsigned num_words);
 
+struct log_capture_state {
+       Jim_Interp *interp;
+       Jim_Obj *output;
+};
+
 static void tcl_output(void *privData, const char *file, unsigned line,
                const char *function, const char *string)
 {
-       Jim_Obj *tclOutput = (Jim_Obj *)privData;
-       Jim_AppendString(interp, tclOutput, string, strlen(string));
+       struct log_capture_state *state = (struct log_capture_state *)privData;
+       Jim_AppendString(state->interp, state->output, string, strlen(string));
+}
+
+static struct log_capture_state *command_log_capture_start(Jim_Interp *interp)
+{
+       /* capture log output and return it. A garbage collect can
+        * happen, so we need a reference count to this object */
+       Jim_Obj *tclOutput = Jim_NewStringObj(interp, "", 0);
+       if (NULL == tclOutput)
+               return NULL;
+
+       struct log_capture_state *state = malloc(sizeof(*state));
+       if (NULL == state)
+               return NULL;
+
+       state->interp = interp;
+       Jim_IncrRefCount(tclOutput);
+       state->output = tclOutput;
+
+       log_add_callback(tcl_output, state);
+
+       return state;
+}
+
+static void command_log_capture_finish(struct log_capture_state *state)
+{
+       if (NULL == state)
+               return;
+
+       log_remove_callback(tcl_output, state);
+
+       Jim_SetResult(state->interp, state->output);
+       Jim_DecrRefCount(state->interp, state->output);
+
+       free(state);
+}
+
+static int command_retval_set(Jim_Interp *interp, int retval)
+{
+       int *return_retval = Jim_GetAssocData(interp, "retval");
+       if (return_retval != NULL)
+               *return_retval = retval;
+
+       return (retval == ERROR_OK) ? JIM_OK : JIM_ERR;
 }
 
 extern struct command_context *global_cmd_ctx;
@@ -108,72 +158,60 @@ static const char **script_command_args_alloc(
        return words;
 }
 
-static int script_command(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+static struct command_context *current_command_context(Jim_Interp *interp)
 {
-       /* the private data is stashed in the interp structure */
-       struct command *c;
-       struct command_context *context;
-       int retval;
-
-       /* DANGER!!!! be careful what we invoke here, since interp->cmdPrivData might
-        * get overwritten by running other Jim commands! Treat it as an
-        * emphemeral global variable that is used in lieu of an argument
-        * to the fn and fish it out manually.
-        */
-       c = interp->cmdPrivData;
-       if (c == NULL)
+       /* grab the command context from the associated data */
+       struct command_context *cmd_ctx = Jim_GetAssocData(interp, "context");
+       if (NULL == cmd_ctx)
        {
-               LOG_ERROR("BUG: interp->cmdPrivData == NULL");
-               return JIM_ERR;
+               /* Tcl can invoke commands directly instead of via command_run_line(). This would
+                * happen when the Jim Tcl interpreter is provided by eCos.
+                */
+               cmd_ctx = global_cmd_ctx;
        }
+       return cmd_ctx;
+}
+
+static int script_command_run(Jim_Interp *interp,
+               int argc, Jim_Obj *const *argv, struct command *c, bool capture)
+{
        target_call_timer_callbacks_now();
        LOG_USER_N("%s", ""); /* Keep GDB connection alive*/
 
-       script_debug(interp, c->name, argc, argv);
-
        unsigned nwords;
        const char **words = script_command_args_alloc(argc, argv, &nwords);
        if (NULL == words)
                return JIM_ERR;
 
-       /* grab the command context from the associated data */
-       context = Jim_GetAssocData(interp, "context");
-       if (context == NULL)
-       {
-               /* Tcl can invoke commands directly instead of via command_run_line(). This would
-                * happen when the Jim Tcl interpreter is provided by eCos.
-                */
-               context = global_cmd_ctx;
-       }
+       struct log_capture_state *state = NULL;
+       if (capture)
+               state = command_log_capture_start(interp);
 
-       /* capture log output and return it */
-       Jim_Obj *tclOutput = Jim_NewStringObj(interp, "", 0);
-       /* a garbage collect can happen, so we need a reference count to this object */
-       Jim_IncrRefCount(tclOutput);
-
-       log_add_callback(tcl_output, tclOutput);
-
-       retval = run_command(context, c, (const char **)words, nwords);
-
-       log_remove_callback(tcl_output, tclOutput);
+       struct command_context *cmd_ctx = current_command_context(interp);
+       int retval = run_command(cmd_ctx, c, (const char **)words, nwords);
 
-       /* We dump output into this local variable */
-       Jim_SetResult(interp, tclOutput);
-       Jim_DecrRefCount(interp, tclOutput);
+       command_log_capture_finish(state);
 
        script_command_args_free(words, nwords);
+       return command_retval_set(interp, retval);
+}
 
-       int *return_retval = Jim_GetAssocData(interp, "retval");
-       if (return_retval != NULL)
-       {
-               *return_retval = retval;
-       }
+static int script_command(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+       /* the private data is stashed in the interp structure */
 
-       return (retval == ERROR_OK)?JIM_OK:JIM_ERR;
+       struct command *c = interp->cmdPrivData;
+       assert(c);
+       script_debug(interp, c->name, argc, argv);
+       return script_command_run(interp, argc, argv, c, true);
 }
 
-/* nice short description of source file */
-#define __THIS__FILE__ "command.c"
+static struct command *command_root(struct command *c)
+{
+       while (NULL != c->parent)
+               c = c->parent;
+       return c;
+}
 
 /**
  * Find a command by name from a list of commands.
@@ -189,6 +227,16 @@ static struct command *command_find(struct command *head, const char *name)
        }
        return NULL;
 }
+struct command *command_find_in_context(struct command_context *cmd_ctx,
+               const char *name)
+{
+       return command_find(cmd_ctx->commands, name);
+}
+struct command *command_find_in_parent(struct command *parent,
+               const char *name)
+{
+       return command_find(parent->children, name);
+}
 
 /**
  * Add the command into the linked list, sorted by name.
@@ -223,27 +271,6 @@ static struct command **command_list_for_parent(
        return parent ? &parent->children : &cmd_ctx->commands;
 }
 
-static struct command *command_new(struct command_context *cmd_ctx,
-               struct command *parent, const char *name,
-               command_handler_t handler, enum command_mode mode,
-               const char *help)
-{
-       assert(name);
-
-       struct command *c = malloc(sizeof(struct command));
-       memset(c, 0, sizeof(struct command));
-
-       c->name = strdup(name);
-       if (help)
-               c->help = strdup(help);
-       c->parent = parent;
-       c->handler = handler;
-       c->mode = mode;
-
-       command_add_child(command_list_for_parent(cmd_ctx, parent), c);
-
-       return c;
-}
 static void command_free(struct command *c)
 {
        /// @todo if command has a handler, unregister its jim command!
@@ -259,17 +286,82 @@ static void command_free(struct command *c)
                free(c->name);
        if (c->help)
                free((void*)c->help);
+       if (c->usage)
+               free((void*)c->usage);
        free(c);
 }
 
+static struct command *command_new(struct command_context *cmd_ctx,
+               struct command *parent, const struct command_registration *cr)
+{
+       assert(cr->name);
+
+       struct command *c = calloc(1, sizeof(struct command));
+       if (NULL == c)
+               return NULL;
+
+       c->name = strdup(cr->name);
+       if (cr->help)
+               c->help = strdup(cr->help);
+       if (cr->usage)
+               c->usage = strdup(cr->usage);
+
+       if (!c->name || (cr->help && !c->help) || (cr->usage && !c->usage))
+               goto command_new_error;
+
+       c->parent = parent;
+       c->handler = cr->handler;
+       c->jim_handler = cr->jim_handler;
+       c->jim_handler_data = cr->jim_handler_data;
+       c->mode = cr->mode;
+
+       command_add_child(command_list_for_parent(cmd_ctx, parent), c);
+
+       return c;
+
+command_new_error:
+       command_free(c);
+       return NULL;
+}
+
+static int command_unknown(Jim_Interp *interp, int argc, Jim_Obj *const *argv);
+
+static int register_command_handler(struct command_context *cmd_ctx,
+               struct command *c)
+{
+       Jim_Interp *interp = cmd_ctx->interp;
+       const char *ocd_name = alloc_printf("ocd_%s", c->name);
+       if (NULL == ocd_name)
+               return JIM_ERR;
+
+       LOG_DEBUG("registering '%s'...", ocd_name);
+
+       Jim_CmdProc func = c->handler ? &script_command : &command_unknown;
+       int retval = Jim_CreateCommand(interp, ocd_name, func, c, NULL);
+       free((void *)ocd_name);
+       if (JIM_OK != retval)
+               return retval;
+
+       /* we now need to add an overrideable proc */
+       const char *override_name = alloc_printf(
+                       "proc %s {args} {eval ocd_bouncer %s $args}",
+                       c->name, c->name);
+       if (NULL == override_name)
+               return JIM_ERR;
+
+       retval = Jim_Eval_Named(interp, override_name, __FILE__, __LINE__);
+       free((void *)override_name);
+
+       return retval;
+}
+
 struct command* register_command(struct command_context *context,
-               struct command *parent, const char *name,
-               command_handler_t handler, enum command_mode mode,
-               const char *help)
+               struct command *parent, const struct command_registration *cr)
 {
-       if (!context || !name)
+       if (!context || !cr->name)
                return NULL;
 
+       const char *name = cr->name;
        struct command **head = command_list_for_parent(context, parent);
        struct command *c = command_find(*head, name);
        if (NULL != c)
@@ -279,28 +371,60 @@ struct command* register_command(struct command_context *context,
                return c;
        }
 
-       c = command_new(context, parent, name, handler, mode, help);
-       /* if allocation failed or it is a placeholder (no handler), we're done */
-       if (NULL == c || NULL == c->handler)
-               return c;
-
-       const char *full_name = command_name(c, '_');
+       c = command_new(context, parent, cr);
+       if (NULL == c)
+               return NULL;
 
-       const char *ocd_name = alloc_printf("ocd_%s", full_name);
-       Jim_CreateCommand(interp, ocd_name, script_command, c, NULL);
-       free((void *)ocd_name);
+       int retval = ERROR_OK;
+       if (NULL != cr->jim_handler && NULL == parent)
+       {
+               retval = Jim_CreateCommand(context->interp, cr->name,
+                               cr->jim_handler, cr->jim_handler_data, NULL);
+       }
+       else if (NULL != cr->handler || NULL != parent)
+               retval = register_command_handler(context, command_root(c));
 
-       /* we now need to add an overrideable proc */
-       const char *override_name = alloc_printf("proc %s {args} {"
-                       "if {[catch {eval ocd_%s $args}] == 0} "
-                       "{return \"\"} else {return -code error}}",
-                       full_name, full_name);
-       Jim_Eval_Named(interp, override_name, __THIS__FILE__, __LINE__);
-       free((void *)override_name);
+       if (ERROR_OK != retval)
+       {
+               unregister_command(context, parent, name);
+               c = NULL;
+       }
+       return c;
+}
 
-       free((void *)full_name);
+int register_commands(struct command_context *cmd_ctx, struct command *parent,
+               const struct command_registration *cmds)
+{
+       int retval = ERROR_OK;
+       unsigned i;
+       for (i = 0; cmds[i].name || cmds[i].chain; i++)
+       {
+               const struct command_registration *cr = cmds + i;
 
-       return c;
+               struct command *c = NULL;
+               if (NULL != cr->name)
+               {
+                       c = register_command(cmd_ctx, parent, cr);
+                       if (NULL == c)
+                       {
+                               retval = ERROR_FAIL;
+                               break;
+                       }
+               }
+               if (NULL != cr->chain)
+               {
+                       struct command *p = c ? : parent;
+                       retval = register_commands(cmd_ctx, p, cr->chain);
+                       if (ERROR_OK != retval)
+                               break;
+               }
+       }
+       if (ERROR_OK != retval)
+       {
+               for (unsigned j = 0; j < i; j++)
+                       unregister_command(cmd_ctx, parent, cmds[j].name);
+       }
+       return retval;
 }
 
 int unregister_all_commands(struct command_context *context,
@@ -345,6 +469,14 @@ int unregister_command(struct command_context *context,
        return ERROR_OK;
 }
 
+void command_set_handler_data(struct command *c, void *p)
+{
+       if (NULL != c->handler || NULL != c->jim_handler)
+               c->jim_handler_data = p;
+       for (struct command *cc = c->children; NULL != cc; cc = cc->next)
+               command_set_handler_data(cc, p);
+}
+
 void command_output_text(struct command_context *context, const char *data)
 {
        if (context && context->output_handler && data) {
@@ -423,18 +555,32 @@ char *command_name(struct command *c, char delim)
        return __command_name(c, delim, 0);
 }
 
+static bool command_can_run(struct command_context *cmd_ctx, struct command *c)
+{
+       return c->mode == COMMAND_ANY || c->mode == cmd_ctx->mode;
+}
+
 static int run_command(struct command_context *context,
                struct command *c, const char *words[], unsigned num_words)
 {
-       if (!((context->mode == COMMAND_CONFIG) || (c->mode == COMMAND_ANY) || (c->mode == context->mode)))
+       if (!command_can_run(context, c))
        {
-               /* Config commands can not run after the config stage */
-               LOG_ERROR("Command '%s' only runs during configuration stage", c->name);
+               /* Many commands may be run only before/after 'init' */
+               const char *when;
+               switch (c->mode) {
+               case COMMAND_CONFIG: when = "before"; break;
+               case COMMAND_EXEC: when = "after"; break;
+               // handle the impossible with humor; it guarantees a bug report!
+               default: when = "if Cthulhu is summoned by"; break;
+               }
+               LOG_ERROR("The '%s' command must be used %s 'init'.",
+                               c->name, when);
                return ERROR_FAIL;
        }
 
        struct command_invocation cmd = {
                        .ctx = context,
+                       .current = c,
                        .name = c->name,
                        .argc = num_words - 1,
                        .argv = words + 1,
@@ -445,7 +591,7 @@ static int run_command(struct command_context *context,
                /* Print help for command */
                char *full_name = command_name(c, ' ');
                if (NULL != full_name) {
-                       command_run_linef(context, "help %s", full_name);
+                       command_run_linef(context, "usage %s", full_name);
                        free(full_name);
                } else
                        retval = -ENOMEM;
@@ -479,6 +625,7 @@ int command_run_line(struct command_context *context, char *line)
         * happen when the Jim Tcl interpreter is provided by eCos for
         * instance.
         */
+       Jim_Interp *interp = context->interp;
        Jim_DeleteAssocData(interp, "context");
        retcode = Jim_SetAssocData(interp, "context", NULL, context);
        if (retcode == JIM_OK)
@@ -566,12 +713,12 @@ struct command_context* copy_command_context(struct command_context* context)
        return copy_context;
 }
 
-int command_done(struct command_context *context)
+void command_done(struct command_context *cmd_ctx)
 {
-       free(context);
-       context = NULL;
+       if (NULL == cmd_ctx)
+               return;
 
-       return ERROR_OK;
+       free(cmd_ctx);
 }
 
 /* find full path to file */
@@ -686,23 +833,13 @@ static int jim_capture(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
        if (argc != 2)
                return JIM_ERR;
-       int retcode;
-       const char *str = Jim_GetString(argv[1], NULL);
-
-       /* capture log output and return it */
-       Jim_Obj *tclOutput = Jim_NewStringObj(interp, "", 0);
-       /* a garbage collect can happen, so we need a reference count to this object */
-       Jim_IncrRefCount(tclOutput);
 
-       log_add_callback(tcl_output, tclOutput);
+       struct log_capture_state *state = command_log_capture_start(interp);
 
-       retcode = Jim_Eval_Named(interp, str, __THIS__FILE__, __LINE__);
-
-       log_remove_callback(tcl_output, tclOutput);
+       const char *str = Jim_GetString(argv[1], NULL);
+       int retcode = Jim_Eval_Named(interp, str, __THIS__FILE__, __LINE__);
 
-       /* We dump output into this local variable */
-       Jim_SetResult(interp, tclOutput);
-       Jim_DecrRefCount(interp, tclOutput);
+       command_log_capture_finish(state);
 
        return retcode;
 }
@@ -713,6 +850,8 @@ static COMMAND_HELPER(command_help_find, struct command *head,
        if (0 == CMD_ARGC)
                return ERROR_INVALID_ARGUMENTS;
        *out = command_find(head, CMD_ARGV[0]);
+       if (NULL == *out && strncmp(CMD_ARGV[0], "ocd_", 4) == 0)
+               *out = command_find(head, CMD_ARGV[0] + 4);
        if (NULL == *out)
                return ERROR_INVALID_ARGUMENTS;
        if (--CMD_ARGC == 0)
@@ -721,57 +860,269 @@ static COMMAND_HELPER(command_help_find, struct command *head,
        return CALL_COMMAND_HANDLER(command_help_find, (*out)->children, out);
 }
 
-static COMMAND_HELPER(command_help_show, struct command *c, unsigned n);
+static COMMAND_HELPER(command_help_show, struct command *c, unsigned n,
+               bool show_help, const char *match);
 
-static COMMAND_HELPER(command_help_show_list, struct command *head, unsigned n)
+static COMMAND_HELPER(command_help_show_list, struct command *head, unsigned n,
+               bool show_help, const char *match)
 {
        for (struct command *c = head; NULL != c; c = c->next)
-               CALL_COMMAND_HANDLER(command_help_show, c, n);
+               CALL_COMMAND_HANDLER(command_help_show, c, n, show_help, match);
        return ERROR_OK;
 }
-static COMMAND_HELPER(command_help_show, struct command *c, unsigned n)
+
+#define HELP_LINE_WIDTH(_n) (int)(76 - (2 * _n))
+
+static void command_help_show_indent(unsigned n)
+{
+       for (unsigned i = 0; i < n; i++)
+               LOG_USER_N("  ");
+}
+static void command_help_show_wrap(const char *str, unsigned n, unsigned n2)
+{
+       const char *cp = str, *last = str;
+       while (*cp)
+       {
+               const char *next = last;
+               do {
+                       cp = next;
+                       do {
+                               next++;
+                       } while (*next != ' ' && *next != '\t' && *next != '\0');
+               } while ((next - last < HELP_LINE_WIDTH(n)) && *next != '\0');
+               if (next - last < HELP_LINE_WIDTH(n))
+                       cp = next;
+               command_help_show_indent(n);
+               LOG_USER_N("%.*s", (int)(cp - last), last);
+               LOG_USER_N("\n");
+               last = cp + 1;
+               n = n2;
+       }
+}
+static COMMAND_HELPER(command_help_show, struct command *c, unsigned n,
+               bool show_help, const char *match)
 {
-       command_run_linef(CMD_CTX, "cmd_help {%s} {%s} %d", command_name(c, ' '),
-                       c->help ? : "no help available", n);
+       if (!command_can_run(CMD_CTX, c))
+               return ERROR_OK;
+
+       char *cmd_name = command_name(c, ' ');
+       if (NULL == cmd_name)
+               return -ENOMEM;
+
+       /* If the match string occurs anywhere, we print out
+        * stuff for this command. */
+       bool is_match = (strstr(cmd_name, match) != NULL) ||
+       ((c->usage != NULL) && (strstr(c->usage, match) != NULL)) ||
+       ((c->help != NULL) && (strstr(c->help, match) != NULL));
+       
+       if (is_match)
+       {
+               command_help_show_indent(n);
+               LOG_USER_N("%s", cmd_name);
+       }
+       free(cmd_name);
+
+       if (is_match)
+       {
+               if (c->usage) {
+                       LOG_USER_N(" ");
+                       command_help_show_wrap(c->usage, 0, n + 5);
+               }
+               else
+                       LOG_USER_N("\n");
+       }
+
+       if (is_match && show_help)
+       {
+               const char *stage_msg;
+               switch (c->mode) {
+               case COMMAND_CONFIG: stage_msg = "CONFIG"; break;
+               case COMMAND_EXEC: stage_msg = "EXEC"; break;
+               case COMMAND_ANY: stage_msg = "CONFIG or EXEC"; break;
+               default: stage_msg = "***UNKNOWN***"; break;
+               }
+               char *msg = alloc_printf("%s%sValid Modes: %s",
+                       c->help ? : "", c->help ? "  " : "", stage_msg);
+               if (NULL != msg)
+               {
+                       command_help_show_wrap(msg, n + 3, n + 3);
+                       free(msg);
+               } else
+                       return -ENOMEM;
+       }
 
        if (++n >= 2)
                return ERROR_OK;
 
-       return CALL_COMMAND_HANDLER(command_help_show_list, c->children, n);
+       return CALL_COMMAND_HANDLER(command_help_show_list,
+                       c->children, n, show_help, match);
 }
 COMMAND_HANDLER(handle_help_command)
 {
+       bool full = strcmp(CMD_NAME, "help") == 0;
+
        struct command *c = CMD_CTX->commands;
 
-       if (0 == CMD_ARGC)
-               return CALL_COMMAND_HANDLER(command_help_show_list, c, 0);
+       const char *match = "";
+       if (CMD_ARGC == 0)
+               match = "";
+       else if (CMD_ARGC == 1)
+               match = CMD_ARGV[0]; 
+       else
+               return ERROR_COMMAND_SYNTAX_ERROR;
+               
+       return CALL_COMMAND_HANDLER(command_help_show_list, c, 0, full, match);
+}
 
-       int retval = CALL_COMMAND_HANDLER(command_help_find, c, &c);
-       if (ERROR_OK != retval)
-               return retval;
+static int command_unknown_find(unsigned argc, Jim_Obj *const *argv,
+               struct command *head, struct command **out, bool top_level)
+{
+       if (0 == argc)
+               return argc;
+       const char *cmd_name = Jim_GetString(argv[0], NULL);
+       struct command *c = command_find(head, cmd_name);
+       if (NULL == c && top_level && strncmp(cmd_name, "ocd_", 4) == 0)
+               c = command_find(head, cmd_name + 4);
+       if (NULL == c)
+               return argc;
+       *out = c;
+       return command_unknown_find(--argc, ++argv, (*out)->children, out, false);
+}
+
+
+static int command_unknown(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+       const char *cmd_name = Jim_GetString(argv[0], NULL);
+       if (strcmp(cmd_name, "unknown") == 0)
+       {
+               if (argc == 1)
+                       return JIM_OK;
+               argc--;
+               argv++;
+       }
+       script_debug(interp, cmd_name, argc, argv);
+
+       struct command_context *cmd_ctx = current_command_context(interp);
+       struct command *c = cmd_ctx->commands;
+       int remaining = command_unknown_find(argc, argv, c, &c, true);
+       // if nothing could be consumed, then it's really an unknown command
+       if (remaining == argc)
+       {
+               const char *cmd = Jim_GetString(argv[0], NULL);
+               LOG_ERROR("Unknown command:\n  %s", cmd);
+               return JIM_OK;
+       }
 
-       return CALL_COMMAND_HANDLER(command_help_show, c, 0);
+       bool found = true;
+       Jim_Obj *const *start;
+       unsigned count;
+       if (c->handler || c->jim_handler)
+       {
+               // include the command name in the list
+               count = remaining + 1;
+               start = argv + (argc - remaining - 1);
+       }
+       else
+       {
+               c = command_find(cmd_ctx->commands, "usage");
+               if (NULL == c)
+               {
+                       LOG_ERROR("unknown command, but usage is missing too");
+                       return JIM_ERR;
+               }
+               count = argc - remaining;
+               start = argv;
+               found = false;
+       }
+       // pass the command through to the intended handler
+       if (c->jim_handler)
+       {
+               interp->cmdPrivData = c->jim_handler_data;
+               return (*c->jim_handler)(interp, count, start);
+       }
+
+       return script_command_run(interp, count, start, c, found);
 }
 
+static int jim_command_mode(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+       struct command_context *cmd_ctx = current_command_context(interp);
+       enum command_mode mode;
+       if (argc > 1)
+       {
+               struct command *c = cmd_ctx->commands;
+               int remaining = command_unknown_find(argc - 1, argv + 1, c, &c, true);
+               // if nothing could be consumed, then it's an unknown command
+               if (remaining == argc - 1)
+               {
+                       Jim_SetResultString(interp, "unknown", -1);
+                       return JIM_OK;
+               }
+               mode = c->mode;
+       }
+       else
+               mode = cmd_ctx->mode;
+
+       const char *mode_str;
+       switch (mode) {
+       case COMMAND_ANY: mode_str = "any"; break;
+       case COMMAND_CONFIG: mode_str = "config"; break;
+       case COMMAND_EXEC: mode_str = "exec"; break;
+       default: mode_str = "unknown"; break;
+       }
+       Jim_SetResultString(interp, mode_str, -1);
+       return JIM_OK;
+}
+
+static int jim_command_type(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+       if (1 == argc)
+               return JIM_ERR;
+
+       struct command_context *cmd_ctx = current_command_context(interp);
+       struct command *c = cmd_ctx->commands;
+       int remaining = command_unknown_find(argc - 1, argv + 1, c, &c, true);
+       // if nothing could be consumed, then it's an unknown command
+       if (remaining == argc - 1)
+       {
+               Jim_SetResultString(interp, "unknown", -1);
+               return JIM_OK;
+       }
+
+       if (c->jim_handler)
+               Jim_SetResultString(interp, "native", -1);
+       else if (c->handler)
+               Jim_SetResultString(interp, "simple", -1);
+       else
+               Jim_SetResultString(interp, "group", -1);
+
+       return JIM_OK;
+}
 
 int help_add_command(struct command_context *cmd_ctx, struct command *parent,
-               const char *cmd_name, const char *help_text)
+               const char *cmd_name, const char *help_text, const char *usage)
 {
        struct command **head = command_list_for_parent(cmd_ctx, parent);
        struct command *nc = command_find(*head, cmd_name);
        if (NULL == nc)
        {
                // add a new command with help text
-               nc = register_command(cmd_ctx, parent, cmd_name,
-                               NULL, COMMAND_ANY, help_text);
+               struct command_registration cr = {
+                               .name = cmd_name,
+                               .mode = COMMAND_ANY,
+                               .help = help_text,
+                               .usage = usage,
+                       };
+               nc = register_command(cmd_ctx, parent, &cr);
                if (NULL == nc)
                {
                        LOG_ERROR("failed to add '%s' help text", cmd_name);
                        return ERROR_FAIL;
                }
                LOG_DEBUG("added '%s' help text", cmd_name);
+               return ERROR_OK;
        }
-       else
+       if (help_text)
        {
                bool replaced = false;
                if (nc->help)
@@ -780,12 +1131,25 @@ int help_add_command(struct command_context *cmd_ctx, struct command *parent,
                        replaced = true;
                }
                nc->help = strdup(help_text);
-
                if (replaced)
                        LOG_INFO("replaced existing '%s' help", cmd_name);
                else
                        LOG_DEBUG("added '%s' help text", cmd_name);
        }
+       if (usage)
+       {
+               bool replaced = false;
+               if (nc->usage)
+               {
+                       free((void *)nc->usage);
+                       replaced = true;
+               }
+               nc->usage = strdup(usage);
+               if (replaced)
+                       LOG_INFO("replaced existing '%s' usage", cmd_name);
+               else
+                       LOG_DEBUG("added '%s' usage text", cmd_name);
+       }
        return ERROR_OK;
 }
 
@@ -798,7 +1162,14 @@ COMMAND_HANDLER(handle_help_add_command)
        }
 
        // save help text and remove it from argument list
-       const char *help_text = CMD_ARGV[--CMD_ARGC];
+       const char *str = CMD_ARGV[--CMD_ARGC];
+       const char *help = !strcmp(CMD_NAME, "add_help_text") ? str : NULL;
+       const char *usage = !strcmp(CMD_NAME, "add_usage_text") ? str : NULL;
+       if (!help && !usage)
+       {
+               LOG_ERROR("command name '%s' is unknown", CMD_NAME);
+               return ERROR_INVALID_ARGUMENTS;
+       }
        // likewise for the leaf command name
        const char *cmd_name = CMD_ARGV[--CMD_ARGC];
 
@@ -810,7 +1181,7 @@ COMMAND_HANDLER(handle_help_add_command)
                if (ERROR_OK != retval)
                        return retval;
        }
-       return help_add_command(CMD_CTX, c, cmd_name, help_text);
+       return help_add_command(CMD_CTX, c, cmd_name, help, usage);
 }
 
 /* sleep command sleeps for <n> miliseconds
@@ -849,7 +1220,74 @@ COMMAND_HANDLER(handle_sleep_command)
        return ERROR_OK;
 }
 
-struct command_context* command_init(const char *startup_tcl)
+static const struct command_registration command_subcommand_handlers[] = {
+       {
+               .name = "mode",
+               .mode = COMMAND_ANY,
+               .jim_handler = &jim_command_mode,
+               .usage = "[<name> ...]",
+               .help = "Returns the command modes allowed by a  command:"
+                       "'any', 'config', or 'exec'.  If no command is"
+                       "specified, returns the current command mode.",
+       },
+       {
+               .name = "type",
+               .mode = COMMAND_ANY,
+               .jim_handler = &jim_command_type,
+               .usage = "<name> ...",
+               .help = "Returns the type of built-in command:"
+                       "'native', 'simple', 'group', or 'unknown'",
+       },
+       COMMAND_REGISTRATION_DONE
+};
+
+static const struct command_registration command_builtin_handlers[] = {
+       {
+               .name = "add_help_text",
+               .handler = &handle_help_add_command,
+               .mode = COMMAND_ANY,
+               .help = "add new command help text",
+               .usage = "<command> [...] <help_text>]",
+       },
+       {
+               .name = "add_usage_text",
+               .handler = &handle_help_add_command,
+               .mode = COMMAND_ANY,
+               .help = "add new command usage text",
+               .usage = "<command> [...] <usage_text>]",
+       },
+       {
+               .name = "sleep",
+               .handler = &handle_sleep_command,
+               .mode = COMMAND_ANY,
+               .help = "sleep for n milliseconds.  "
+                       "\"busy\" will busy wait",
+               .usage = "<n> [busy]",
+       },
+       {
+               .name = "help",
+               .handler = &handle_help_command,
+               .mode = COMMAND_ANY,
+               .help = "show full command help",
+               .usage = "[<command> ...]",
+       },
+       {
+               .name = "usage",
+               .handler = &handle_help_command,
+               .mode = COMMAND_ANY,
+               .help = "show basic command usage",
+               .usage = "[<command> ...]",
+       },
+       {
+               .name = "command",
+               .mode= COMMAND_ANY,
+               .help = "core command group (introspection)",
+               .chain = command_subcommand_handlers,
+       },
+       COMMAND_REGISTRATION_DONE
+};
+
+struct command_context* command_init(const char *startup_tcl, Jim_Interp *interp)
 {
        struct command_context* context = malloc(sizeof(struct command_context));
        const char *HostOs;
@@ -861,12 +1299,17 @@ struct command_context* command_init(const char *startup_tcl)
        context->output_handler_priv = NULL;
 
 #if !BUILD_ECOSBOARD
-       Jim_InitEmbedded();
-       /* Create an interpreter */
-       interp = Jim_CreateInterp();
-       /* Add all the Jim core commands */
-       Jim_RegisterCoreCommands(interp);
+       /* Create a jim interpreter if we were not handed one */
+       if (interp == NULL)
+       {
+               Jim_InitEmbedded();
+               /* Create an interpreter */
+               interp = Jim_CreateInterp();
+               /* Add all the Jim core commands */
+               Jim_RegisterCoreCommands(interp);
+       }
 #endif
+       context->interp = interp;
 
 #if defined(_MSC_VER)
        /* WinXX - is generic, the forward
@@ -908,10 +1351,7 @@ struct command_context* command_init(const char *startup_tcl)
        interp->cb_fflush = openocd_jim_fflush;
        interp->cb_fgets = openocd_jim_fgets;
 
-       COMMAND_REGISTER(context, NULL, "add_help_text",
-                       handle_help_add_command, COMMAND_ANY,
-                       "<command> [...] <help_text>] - "
-                       "add new command help text");
+       register_commands(context, NULL, command_builtin_handlers);
 
 #if !BUILD_ECOSBOARD
        Jim_EventLoopOnLoad(interp);
@@ -925,15 +1365,6 @@ struct command_context* command_init(const char *startup_tcl)
        }
        Jim_DeleteAssocData(interp, "context");
 
-       COMMAND_REGISTER(context, NULL, "sleep",
-                       handle_sleep_command, COMMAND_ANY,
-                       "<n> [busy] - sleep for n milliseconds. "
-                       "\"busy\" means busy wait");
-
-       COMMAND_REGISTER(context, NULL, "help",
-                       &handle_help_command, COMMAND_ANY,
-                       "[<command_name> ...] - show built-in command help");
-
        return context;
 }
 
@@ -946,32 +1377,19 @@ int command_context_mode(struct command_context *cmd_ctx, enum command_mode mode
        return ERROR_OK;
 }
 
-void process_jim_events(void)
+void process_jim_events(struct command_context *cmd_ctx)
 {
 #if !BUILD_ECOSBOARD
        static int recursion = 0;
+       if (recursion)
+               return;
 
-       if (!recursion)
-       {
-               recursion++;
-               Jim_ProcessEvents (interp, JIM_ALL_EVENTS | JIM_DONT_WAIT);
-               recursion--;
-       }
+       recursion++;
+       Jim_ProcessEvents(cmd_ctx->interp, JIM_ALL_EVENTS | JIM_DONT_WAIT);
+       recursion--;
 #endif
 }
 
-void register_jim(struct command_context *cmd_ctx, const char *name,
-               Jim_CmdProc cmd, const char *help)
-{
-       Jim_CreateCommand(interp, name, cmd, NULL, NULL);
-
-       Jim_Obj *cmd_list = Jim_NewListObj(interp, NULL, 0);
-       Jim_ListAppendElement(interp, cmd_list,
-                       Jim_NewStringObj(interp, name, -1));
-
-       help_add_command(cmd_ctx, NULL, name, help);
-}
-
 #define DEFINE_PARSE_NUM_TYPE(name, type, func, min, max) \
        int parse##name(const char *str, type *ul) \
        { \