combine help and usage command handlers

[openocd.git] / src / helper / command.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008, Duane Ellis                                       *
 *   openocd@duaneeellis.com                                               *
 *                                                                         *
 *   part of this file is taken from libcli (libcli.sourceforge.net)       *
 *   Copyright (C) David Parrish (david@dparrish.com)                      *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#if !BUILD_ECOSBOARD
/* see Embedder-HOWTO.txt in Jim Tcl project hosted on BerliOS*/
#define JIM_EMBEDDED
#endif

// @todo the inclusion of target.h here is a layering violation
#include "target.h"
#include "command.h"
#include "configuration.h"
#include "log.h"
#include "time_support.h"
#include "jim-eventloop.h"


Jim_Interp *interp = NULL;

static int run_command(struct command_context *context,
                struct command *c, const char *words[], unsigned num_words);

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));
}

extern struct command_context *global_cmd_ctx;

void script_debug(Jim_Interp *interp, const char *name,
                unsigned argc, Jim_Obj *const *argv)
{
        LOG_DEBUG("command - %s", name);
        for (unsigned i = 0; i < argc; i++)
        {
                int len;
                const char *w = Jim_GetString(argv[i], &len);

                /* end of line comment? */
                if (*w == '#')
                        break;

                LOG_DEBUG("%s - argv[%d]=%s", name, i, w);
        }
}

static void script_command_args_free(const char **words, unsigned nwords)
{
        for (unsigned i = 0; i < nwords; i++)
                free((void *)words[i]);
        free(words);
}
static const char **script_command_args_alloc(
                unsigned argc, Jim_Obj *const *argv, unsigned *nwords)
{
        const char **words = malloc(argc * sizeof(char *));
        if (NULL == words)
                return NULL;

        unsigned i;
        for (i = 0; i < argc; i++)
        {
                int len;
                const char *w = Jim_GetString(argv[i], &len);
                /* a comment may end the line early */
                if (*w == '#')
                        break;

                words[i] = strdup(w);
                if (words[i] == NULL)
                {
                        script_command_args_free(words, i);
                        return NULL;
                }
        }
        *nwords = i;
        return words;
}

static struct command_context *current_command_context(void)
{
        /* grab the command context from the associated data */
        struct command_context *cmd_ctx = Jim_GetAssocData(interp, "context");
        if (NULL == cmd_ctx)
        {
                /* 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(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
{
        /* the private data is stashed in the interp structure */
        struct command *c;
        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)
        {
                LOG_ERROR("BUG: interp->cmdPrivData == NULL");
                return JIM_ERR;
        }
        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;

        /* 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 command_context *cmd_ctx = current_command_context();
        retval = run_command(cmd_ctx, c, (const char **)words, nwords);

        log_remove_callback(tcl_output, tclOutput);

        /* We dump output into this local variable */
        Jim_SetResult(interp, tclOutput);
        Jim_DecrRefCount(interp, tclOutput);

        script_command_args_free(words, nwords);

        int *return_retval = Jim_GetAssocData(interp, "retval");
        if (return_retval != NULL)
        {
                *return_retval = retval;
        }

        return (retval == ERROR_OK)?JIM_OK:JIM_ERR;
}

/* nice short description of source file */
#define __THIS__FILE__ "command.c"

/**
 * Find a command by name from a list of commands.
 * @returns Returns the named command if it exists in the list.
 * Returns NULL otherwise.
 */
static struct command *command_find(struct command *head, const char *name)
{
        for (struct command *cc = head; cc; cc = cc->next)
        {
                if (strcmp(cc->name, name) == 0)
                        return cc;
        }
        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.
 * @param head Address to head of command list pointer, which may be
 * updated if @c c gets inserted at the beginning of the list.
 * @param c The command to add to the list pointed to by @c head.
 */
static void command_add_child(struct command **head, struct command *c)
{
        assert(head);
        if (NULL == *head)
        {
                *head = c;
                return;
        }

        while ((*head)->next && (strcmp(c->name, (*head)->name) > 0))
                head = &(*head)->next;

        if (strcmp(c->name, (*head)->name) > 0) {
                c->next = (*head)->next;
                (*head)->next = c;
        } else {
                c->next = *head;
                *head = c;
        }
}

static struct command **command_list_for_parent(
                struct command_context *cmd_ctx, struct command *parent)
{
        return parent ? &parent->children : &cmd_ctx->commands;
}

static struct command *command_new(struct command_context *cmd_ctx,
                struct command *parent, const struct command_registration *cr)
{
        assert(cr->name);

        struct command *c = malloc(sizeof(struct command));
        memset(c, 0, sizeof(struct command));

        c->name = strdup(cr->name);
        if (cr->help)
                c->help = strdup(cr->help);
        if (cr->usage)
                c->usage = strdup(cr->usage);
        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;
}
static void command_free(struct command *c)
{
        /// @todo if command has a handler, unregister its jim command!

        while (NULL != c->children)
        {
                struct command *tmp = c->children;
                c->children = tmp->next;
                command_free(tmp);
        }

        if (c->name)
                free(c->name);
        if (c->help)
                free((void*)c->help);
        if (c->usage)
                free((void*)c->usage);
        free(c);
}

static int register_command_handler(struct command *c)
{
        int retval = -ENOMEM;
        const char *full_name = command_name(c, '_');
        if (NULL == full_name)
                return retval;

        const char *ocd_name = alloc_printf("ocd_%s", full_name);
        if (NULL == full_name)
                goto free_full_name;

        Jim_CreateCommand(interp, ocd_name, script_command, c, NULL);
        free((void *)ocd_name);

        /* 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);
        if (NULL == full_name)
                goto free_full_name;

        Jim_Eval_Named(interp, override_name, __THIS__FILE__, __LINE__);
        free((void *)override_name);

        retval = ERROR_OK;

free_full_name:
        free((void *)full_name);
        return retval;
}

struct command* register_command(struct command_context *context,
                struct command *parent, const struct command_registration *cr)
{
        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)
        {
                LOG_ERROR("command '%s' is already registered in '%s' context",
                                name, parent ? parent->name : "<global>");
                return c;
        }

        c = command_new(context, parent, cr);
        if (NULL == c)
                return NULL;

        if (NULL != c->handler)
        {
                int retval = register_command_handler(c);
                if (ERROR_OK != retval)
                {
                        unregister_command(context, parent, name);
                        return NULL;
                }
        }

        if (NULL != cr->jim_handler && NULL == parent)
                Jim_CreateCommand(interp, cr->name, cr->jim_handler, cr->jim_handler_data, NULL);

        return c;
}

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;

                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,
                struct command *parent)
{
        if (context == NULL)
                return ERROR_OK;

        struct command **head = command_list_for_parent(context, parent);
        while (NULL != *head)
        {
                struct command *tmp = *head;
                *head = tmp->next;
                command_free(tmp);
        }

        return ERROR_OK;
}

int unregister_command(struct command_context *context,
                struct command *parent, const char *name)
{
        if ((!context) || (!name))
                return ERROR_INVALID_ARGUMENTS;

        struct command *p = NULL;
        struct command **head = command_list_for_parent(context, parent);
        for (struct command *c = *head; NULL != c; p = c, c = c->next)
        {
                if (strcmp(name, c->name) != 0)
                        continue;

                if (p)
                        p->next = c->next;
                else
                        *head = c->next;

                command_free(c);
                return ERROR_OK;
        }

        return ERROR_OK;
}

void command_output_text(struct command_context *context, const char *data)
{
        if (context && context->output_handler && data) {
                context->output_handler(context, data);
        }
}

void command_print_sameline(struct command_context *context, const char *format, ...)
{
        char *string;

        va_list ap;
        va_start(ap, format);

        string = alloc_vprintf(format, ap);
        if (string != NULL)
        {
                /* we want this collected in the log + we also want to pick it up as a tcl return
                 * value.
                 *
                 * The latter bit isn't precisely neat, but will do for now.
                 */
                LOG_USER_N("%s", string);
                /* We already printed it above */
                /* command_output_text(context, string); */
                free(string);
        }

        va_end(ap);
}

void command_print(struct command_context *context, const char *format, ...)
{
        char *string;

        va_list ap;
        va_start(ap, format);

        string = alloc_vprintf(format, ap);
        if (string != NULL)
        {
                strcat(string, "\n"); /* alloc_vprintf guaranteed the buffer to be at least one char longer */
                /* we want this collected in the log + we also want to pick it up as a tcl return
                 * value.
                 *
                 * The latter bit isn't precisely neat, but will do for now.
                 */
                LOG_USER_N("%s", string);
                /* We already printed it above */
                /* command_output_text(context, string); */
                free(string);
        }

        va_end(ap);
}

static char *__command_name(struct command *c, char delim, unsigned extra)
{
        char *name;
        unsigned len = strlen(c->name);
        if (NULL == c->parent) {
                // allocate enough for the name, child names, and '\0'
                name = malloc(len + extra + 1);
                strcpy(name, c->name);
        } else {
                // parent's extra must include both the space and name
                name = __command_name(c->parent, delim, 1 + len + extra);
                char dstr[2] = { delim, 0 };
                strcat(name, dstr);
                strcat(name, c->name);
        }
        return name;
}
char *command_name(struct command *c, char delim)
{
        return __command_name(c, delim, 0);
}

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)))
        {
                /* Config commands can not run after the config stage */
                LOG_ERROR("Command '%s' only runs during configuration stage", c->name);
                return ERROR_FAIL;
        }

        struct command_invocation cmd = {
                        .ctx = context,
                        .name = c->name,
                        .argc = num_words - 1,
                        .argv = words + 1,
                };
        int retval = c->handler(&cmd);
        if (retval == ERROR_COMMAND_SYNTAX_ERROR)
        {
                /* Print help for command */
                char *full_name = command_name(c, ' ');
                if (NULL != full_name) {
                        command_run_linef(context, "help %s", full_name);
                        free(full_name);
                } else
                        retval = -ENOMEM;
        }
        else if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
        {
                /* just fall through for a shutdown request */
        }
        else if (retval != ERROR_OK)
        {
                /* we do not print out an error message because the command *should*
                 * have printed out an error
                 */
                LOG_DEBUG("Command failed with error code %d", retval);
        }

        return retval;
}

int command_run_line(struct command_context *context, char *line)
{
        /* all the parent commands have been registered with the interpreter
         * so, can just evaluate the line as a script and check for
         * results
         */
        /* run the line thru a script engine */
        int retval = ERROR_FAIL;
        int retcode;
        /* Beware! This code needs to be reentrant. It is also possible
         * for OpenOCD commands to be invoked directly from Tcl. This would
         * happen when the Jim Tcl interpreter is provided by eCos for
         * instance.
         */
        Jim_DeleteAssocData(interp, "context");
        retcode = Jim_SetAssocData(interp, "context", NULL, context);
        if (retcode == JIM_OK)
        {
                /* associated the return value */
                Jim_DeleteAssocData(interp, "retval");
                retcode = Jim_SetAssocData(interp, "retval", NULL, &retval);
                if (retcode == JIM_OK)
                {
                        retcode = Jim_Eval_Named(interp, line, __THIS__FILE__, __LINE__);

                        Jim_DeleteAssocData(interp, "retval");
                }
                Jim_DeleteAssocData(interp, "context");
        }
        if (retcode == JIM_ERR) {
                if (retval != ERROR_COMMAND_CLOSE_CONNECTION)
                {
                        /* We do not print the connection closed error message */
                        Jim_PrintErrorMessage(interp);
                }
                if (retval == ERROR_OK)
                {
                        /* It wasn't a low level OpenOCD command that failed */
                        return ERROR_FAIL;
                }
                return retval;
        } else if (retcode == JIM_EXIT) {
                /* ignore. */
                /* exit(Jim_GetExitCode(interp)); */
        } else {
                const char *result;
                int reslen;

                result = Jim_GetString(Jim_GetResult(interp), &reslen);
                if (reslen > 0)
                {
                        int i;
                        char buff[256 + 1];
                        for (i = 0; i < reslen; i += 256)
                        {
                                int chunk;
                                chunk = reslen - i;
                                if (chunk > 256)
                                        chunk = 256;
                                strncpy(buff, result + i, chunk);
                                buff[chunk] = 0;
                                LOG_USER_N("%s", buff);
                        }
                        LOG_USER_N("%s", "\n");
                }
                retval = ERROR_OK;
        }
        return retval;
}

int command_run_linef(struct command_context *context, const char *format, ...)
{
        int retval = ERROR_FAIL;
        char *string;
        va_list ap;
        va_start(ap, format);
        string = alloc_vprintf(format, ap);
        if (string != NULL)
        {
                retval = command_run_line(context, string);
        }
        va_end(ap);
        return retval;
}

void command_set_output_handler(struct command_context* context,
                command_output_handler_t output_handler, void *priv)
{
        context->output_handler = output_handler;
        context->output_handler_priv = priv;
}

struct command_context* copy_command_context(struct command_context* context)
{
        struct command_context* copy_context = malloc(sizeof(struct command_context));

        *copy_context = *context;

        return copy_context;
}

int command_done(struct command_context *context)
{
        free(context);
        context = NULL;

        return ERROR_OK;
}

/* find full path to file */
static int jim_find(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
{
        if (argc != 2)
                return JIM_ERR;
        const char *file = Jim_GetString(argv[1], NULL);
        char *full_path = find_file(file);
        if (full_path == NULL)
                return JIM_ERR;
        Jim_Obj *result = Jim_NewStringObj(interp, full_path, strlen(full_path));
        free(full_path);

        Jim_SetResult(interp, result);
        return JIM_OK;
}

static int jim_echo(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
{
        if (argc != 2)
                return JIM_ERR;
        const char *str = Jim_GetString(argv[1], NULL);
        LOG_USER("%s", str);
        return JIM_OK;
}

static size_t openocd_jim_fwrite(const void *_ptr, size_t size, size_t n, void *cookie)
{
        size_t nbytes;
        const char *ptr;
        Jim_Interp *interp;

        /* make it a char easier to read code */
        ptr = _ptr;
        interp = cookie;
        nbytes = size * n;
        if (ptr == NULL || interp == NULL || nbytes == 0) {
                return 0;
        }

        /* do we have to chunk it? */
        if (ptr[nbytes] == 0)
        {
                /* no it is a C style string */
                LOG_USER_N("%s", ptr);
                return strlen(ptr);
        }
        /* GRR we must chunk - not null terminated */
        while (nbytes) {
                char chunk[128 + 1];
                int x;

                x = nbytes;
                if (x > 128) {
                        x = 128;
                }
                /* copy it */
                memcpy(chunk, ptr, x);
                /* terminate it */
                chunk[n] = 0;
                /* output it */
                LOG_USER_N("%s", chunk);
                ptr += x;
                nbytes -= x;
        }

        return n;
}

static size_t openocd_jim_fread(void *ptr, size_t size, size_t n, void *cookie)
{
        /* TCL wants to read... tell him no */
        return 0;
}

static int openocd_jim_vfprintf(void *cookie, const char *fmt, va_list ap)
{
        char *cp;
        int n;
        Jim_Interp *interp;

        n = -1;
        interp = cookie;
        if (interp == NULL)
                return n;

        cp = alloc_vprintf(fmt, ap);
        if (cp)
        {
                LOG_USER_N("%s", cp);
                n = strlen(cp);
                free(cp);
        }
        return n;
}

static int openocd_jim_fflush(void *cookie)
{
        /* nothing to flush */
        return 0;
}

static char* openocd_jim_fgets(char *s, int size, void *cookie)
{
        /* not supported */
        errno = ENOTSUP;
        return NULL;
}

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);

        retcode = Jim_Eval_Named(interp, str, __THIS__FILE__, __LINE__);

        log_remove_callback(tcl_output, tclOutput);

        /* We dump output into this local variable */
        Jim_SetResult(interp, tclOutput);
        Jim_DecrRefCount(interp, tclOutput);

        return retcode;
}

static COMMAND_HELPER(command_help_find, struct command *head,
                struct command **out)
{
        if (0 == CMD_ARGC)
                return ERROR_INVALID_ARGUMENTS;
        *out = command_find(head, CMD_ARGV[0]);
        if (NULL == *out)
                return ERROR_INVALID_ARGUMENTS;
        if (--CMD_ARGC == 0)
                return ERROR_OK;
        CMD_ARGV++;
        return CALL_COMMAND_HANDLER(command_help_find, (*out)->children, out);
}

static COMMAND_HELPER(command_help_show, struct command *c, unsigned n,
                bool show_help);

static COMMAND_HELPER(command_help_show_list, struct command *head, unsigned n,
                bool show_help)
{
        for (struct command *c = head; NULL != c; c = c->next)
                CALL_COMMAND_HANDLER(command_help_show, c, n, show_help);
        return ERROR_OK;
}

#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)
{
        command_help_show_indent(n);
        LOG_USER_N("%s", command_name(c, ' '));
        if (c->usage) {
                LOG_USER_N(" ");
                command_help_show_wrap(c->usage, 0, n + 5);
        }
        else
                LOG_USER_N("\n");
        if (show_help && c->help)
                command_help_show_wrap(c->help, n + 3, n + 3);
        if (++n >= 2)
                return ERROR_OK;

        return CALL_COMMAND_HANDLER(command_help_show_list,
                        c->children, n, show_help);
}
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, full);

        int retval = CALL_COMMAND_HANDLER(command_help_find, c, &c);
        if (ERROR_OK != retval)
                return retval;

        return CALL_COMMAND_HANDLER(command_help_show, c, 0, full);
}

static int command_unknown_find(unsigned argc, Jim_Obj *const *argv,
                struct command *head, struct command **out)
{
        if (0 == argc)
                return argc;
        struct command *c = command_find(head, Jim_GetString(argv[0], NULL));
        if (NULL == c)
                return argc;
        *out = c;
        return command_unknown_find(--argc, ++argv, (*out)->children, out);
}

static int command_unknown(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
{
        const char *cmd_name = Jim_GetString(argv[0], NULL);
        script_debug(interp, cmd_name, argc - 1, argv + 1);

        struct command_context *cmd_ctx = current_command_context();
        struct command *c = cmd_ctx->commands;
        int remaining = command_unknown_find(argc - 1, argv + 1, c, &c);
        // if nothing could be consumed, then it's really an unknown command
        if (remaining == argc - 1)
        {
                const char *cmd = Jim_GetString(argv[1], NULL);
                LOG_ERROR("Unknown command:\n  %s", cmd);
                return JIM_OK;
        }

        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, "help");
                if (NULL == c)
                {
                        LOG_ERROR("unknown command, but help 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);
        }

        unsigned nwords;
        const char **words = script_command_args_alloc(count, start, &nwords);
        if (NULL == words)
                return JIM_ERR;

        int retval = run_command(cmd_ctx, c, words, nwords);

        script_command_args_free(words, nwords);

        if (!found && ERROR_OK == retval)
                retval = ERROR_FAIL;

        return retval;
}

int help_add_command(struct command_context *cmd_ctx, struct command *parent,
                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
                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;
        }
        if (help_text)
        {
                bool replaced = false;
                if (nc->help)
                {
                        free((void *)nc->help);
                        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;
}

COMMAND_HANDLER(handle_help_add_command)
{
        if (CMD_ARGC < 2)
        {
                LOG_ERROR("%s: insufficient arguments", CMD_NAME);
                return ERROR_INVALID_ARGUMENTS;
        }

        // save help text and remove it from argument list
        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];

        struct command *c = NULL;
        if (CMD_ARGC > 0)
        {
                c = CMD_CTX->commands;
                int retval = CALL_COMMAND_HANDLER(command_help_find, c, &c);
                if (ERROR_OK != retval)
                        return retval;
        }
        return help_add_command(CMD_CTX, c, cmd_name, help, usage);
}

/* sleep command sleeps for <n> miliseconds
 * this is useful in target startup scripts
 */
COMMAND_HANDLER(handle_sleep_command)
{
        bool busy = false;
        if (CMD_ARGC == 2)
        {
                if (strcmp(CMD_ARGV[1], "busy") == 0)
                        busy = true;
                else
                        return ERROR_COMMAND_SYNTAX_ERROR;
        }
        else if (CMD_ARGC < 1 || CMD_ARGC > 2)
                return ERROR_COMMAND_SYNTAX_ERROR;

        unsigned long duration = 0;
        int retval = parse_ulong(CMD_ARGV[0], &duration);
        if (ERROR_OK != retval)
                return retval;

        if (!busy)
        {
                long long then = timeval_ms();
                while (timeval_ms() - then < (long long)duration)
                {
                        target_call_timer_callbacks_now();
                        usleep(1000);
                }
        }
        else
                busy_sleep(duration);

        return ERROR_OK;
}

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> ...]",
        },
        COMMAND_REGISTRATION_DONE
};

struct command_context* command_init(const char *startup_tcl)
{
        struct command_context* context = malloc(sizeof(struct command_context));
        const char *HostOs;

        context->mode = COMMAND_EXEC;
        context->commands = NULL;
        context->current_target = 0;
        context->output_handler = NULL;
        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);
#endif

#if defined(_MSC_VER)
        /* WinXX - is generic, the forward
         * looking problem is this:
         *
         *   "win32" or "win64"
         *
         * "winxx" is generic.
         */
        HostOs = "winxx";
#elif defined(__linux__)
        HostOs = "linux";
#elif defined(__DARWIN__)
        HostOs = "darwin";
#elif defined(__CYGWIN__)
        HostOs = "cygwin";
#elif defined(__MINGW32__)
        HostOs = "mingw32";
#elif defined(__ECOS)
        HostOs = "ecos";
#else
#warn unrecognized host OS...
        HostOs = "other";
#endif
        Jim_SetGlobalVariableStr(interp, "ocd_HOSTOS",
                        Jim_NewStringObj(interp, HostOs , strlen(HostOs)));

        Jim_CreateCommand(interp, "unknown", &command_unknown, NULL, NULL);
        Jim_CreateCommand(interp, "ocd_find", jim_find, NULL, NULL);
        Jim_CreateCommand(interp, "echo", jim_echo, NULL, NULL);
        Jim_CreateCommand(interp, "capture", jim_capture, NULL, NULL);

        /* Set Jim's STDIO */
        interp->cookie_stdin = interp;
        interp->cookie_stdout = interp;
        interp->cookie_stderr = interp;
        interp->cb_fwrite = openocd_jim_fwrite;
        interp->cb_fread = openocd_jim_fread ;
        interp->cb_vfprintf = openocd_jim_vfprintf;
        interp->cb_fflush = openocd_jim_fflush;
        interp->cb_fgets = openocd_jim_fgets;

        register_commands(context, NULL, command_builtin_handlers);

#if !BUILD_ECOSBOARD
        Jim_EventLoopOnLoad(interp);
#endif
        Jim_SetAssocData(interp, "context", NULL, context);
        if (Jim_Eval_Named(interp, startup_tcl, "embedded:startup.tcl",1) == JIM_ERR)
        {
                LOG_ERROR("Failed to run startup.tcl (embedded into OpenOCD)");
                Jim_PrintErrorMessage(interp);
                exit(-1);
        }
        Jim_DeleteAssocData(interp, "context");

        return context;
}

int command_context_mode(struct command_context *cmd_ctx, enum command_mode mode)
{
        if (!cmd_ctx)
                return ERROR_INVALID_ARGUMENTS;

        cmd_ctx->mode = mode;
        return ERROR_OK;
}

void process_jim_events(void)
{
#if !BUILD_ECOSBOARD
        static int recursion = 0;

        if (!recursion)
        {
                recursion++;
                Jim_ProcessEvents (interp, JIM_ALL_EVENTS | JIM_DONT_WAIT);
                recursion--;
        }
#endif
}

#define DEFINE_PARSE_NUM_TYPE(name, type, func, min, max) \
        int parse##name(const char *str, type *ul) \
        { \
                if (!*str) \
                { \
                        LOG_ERROR("Invalid command argument"); \
                        return ERROR_COMMAND_ARGUMENT_INVALID; \
                } \
                char *end; \
                *ul = func(str, &end, 0); \
                if (*end) \
                { \
                        LOG_ERROR("Invalid command argument"); \
                        return ERROR_COMMAND_ARGUMENT_INVALID; \
                } \
                if ((max == *ul) && (ERANGE == errno)) \
                { \
                        LOG_ERROR("Argument overflow"); \
                        return ERROR_COMMAND_ARGUMENT_OVERFLOW; \
                } \
                if (min && (min == *ul) && (ERANGE == errno)) \
                { \
                        LOG_ERROR("Argument underflow"); \
                        return ERROR_COMMAND_ARGUMENT_UNDERFLOW; \
                } \
                return ERROR_OK; \
        }
DEFINE_PARSE_NUM_TYPE(_ulong, unsigned long , strtoul, 0, ULONG_MAX)
DEFINE_PARSE_NUM_TYPE(_ullong, unsigned long long, strtoull, 0, ULLONG_MAX)
DEFINE_PARSE_NUM_TYPE(_long, long , strtol, LONG_MIN, LONG_MAX)
DEFINE_PARSE_NUM_TYPE(_llong, long long, strtoll, LLONG_MIN, LLONG_MAX)

#define DEFINE_PARSE_WRAPPER(name, type, min, max, functype, funcname) \
        int parse##name(const char *str, type *ul) \
        { \
                functype n; \
                int retval = parse##funcname(str, &n); \
                if (ERROR_OK != retval) \
                        return retval; \
                if (n > max) \
                        return ERROR_COMMAND_ARGUMENT_OVERFLOW; \
                if (min) \
                        return ERROR_COMMAND_ARGUMENT_UNDERFLOW; \
                *ul = n; \
                return ERROR_OK; \
        }

#define DEFINE_PARSE_ULONG(name, type, min, max) \
        DEFINE_PARSE_WRAPPER(name, type, min, max, unsigned long, _ulong)
DEFINE_PARSE_ULONG(_uint, unsigned, 0, UINT_MAX)
DEFINE_PARSE_ULONG(_u32, uint32_t, 0, UINT32_MAX)
DEFINE_PARSE_ULONG(_u16, uint16_t, 0, UINT16_MAX)
DEFINE_PARSE_ULONG(_u8, uint8_t, 0, UINT8_MAX)

#define DEFINE_PARSE_LONG(name, type, min, max) \
        DEFINE_PARSE_WRAPPER(name, type, min, max, long, _long)
DEFINE_PARSE_LONG(_int, int, n < INT_MIN, INT_MAX)
DEFINE_PARSE_LONG(_s32, int32_t, n < INT32_MIN, INT32_MAX)
DEFINE_PARSE_LONG(_s16, int16_t, n < INT16_MIN, INT16_MAX)
DEFINE_PARSE_LONG(_s8, int8_t, n < INT8_MIN, INT8_MAX)

static int command_parse_bool(const char *in, bool *out,
                const char *on, const char *off)
{
        if (strcasecmp(in, on) == 0)
                *out = true;
        else if (strcasecmp(in, off) == 0)
                *out = false;
        else
                return ERROR_COMMAND_SYNTAX_ERROR;
        return  ERROR_OK;
}

int command_parse_bool_arg(const char *in, bool *out)
{
        if (command_parse_bool(in, out, "on", "off") == ERROR_OK)
                return ERROR_OK;
        if (command_parse_bool(in, out, "enable", "disable") == ERROR_OK)
                return ERROR_OK;
        if (command_parse_bool(in, out, "true", "false") == ERROR_OK)
                return ERROR_OK;
        if (command_parse_bool(in, out, "yes", "no") == ERROR_OK)
                return ERROR_OK;
        if (command_parse_bool(in, out, "1", "0") == ERROR_OK)
                return ERROR_OK;
        return ERROR_INVALID_ARGUMENTS;
}

COMMAND_HELPER(handle_command_parse_bool, bool *out, const char *label)
{
        switch (CMD_ARGC) {
        case 1: {
                const char *in = CMD_ARGV[0];
                if (command_parse_bool_arg(in, out) != ERROR_OK)
                {
                        LOG_ERROR("%s: argument '%s' is not valid", CMD_NAME, in);
                        return ERROR_INVALID_ARGUMENTS;
                }
                // fall through
        }
        case 0:
                LOG_INFO("%s is %s", label, *out ? "enabled" : "disabled");
                break;
        default:
                return ERROR_INVALID_ARGUMENTS;
        }
        return ERROR_OK;
}