source: mainline/kernel/generic/src/console/kconsole.c

/*
 * Copyright (c) 2005 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup kernel_generic_console
 * @{
 */

/**
 * @file  kconsole.c
 * @brief Kernel console.
 *
 * This file contains kernel thread managing the kernel console.
 *
 */

#include <adt/list.h>
#include <arch.h>
#include <assert.h>
#include <console/chardev.h>
#include <console/cmd.h>
#include <console/console.h>
#include <console/kconsole.h>
#include <console/prompt.h>
#include <debug.h>
#include <errno.h>
#include <halt.h>
#include <macros.h>
#include <panic.h>
#include <stdio.h>
#include <stdlib.h>
#include <str.h>
#include <symtab.h>
#include <sysinfo/sysinfo.h>
#include <typedefs.h>

/** Simple kernel console.
 *
 * The console is realized by kernel thread kconsole.
 * It doesn't understand any useful command on its own,
 * but makes it possible for other kernel subsystems to
 * register their own commands.
 */

/** Locking.
 *
 * There is a list of cmd_info_t structures. This list
 * is protected by cmd_lock spinlock. Note that specially
 * the link elements of cmd_info_t are protected by
 * this lock.
 *
 * Each cmd_info_t also has its own lock, which protects
 * all elements thereof except the link element.
 *
 * cmd_lock must be acquired before any cmd_info lock.
 * When locking two cmd info structures, structure with
 * lower address must be locked first.
 */

SPINLOCK_INITIALIZE(cmd_lock);  /**< Lock protecting command list. */
LIST_INITIALIZE(cmd_list);      /**< Command list. */

#define MAX_SYMBOL_NAME 64

static char32_t history[KCONSOLE_HISTORY][MAX_CMDLINE] = { };
static size_t history_pos = 0;

/** Initialize kconsole data structures
 *
 * This is the most basic initialization, almost no
 * other kernel subsystem is ready yet.
 *
 */
void kconsole_init(void)
{
        unsigned int i;

        cmd_init();
        for (i = 0; i < KCONSOLE_HISTORY; i++)
                history[i][0] = 0;
}

/** Register kconsole command.
 *
 * @param cmd Structure describing the command.
 *
 * @return False on failure, true on success.
 *
 */
bool cmd_register(cmd_info_t *cmd)
{
        spinlock_lock(&cmd_lock);

        /*
         * Make sure the command is not already listed.
         */
        list_foreach(cmd_list, link, cmd_info_t, hlp) {
                if (hlp == cmd) {
                        /* The command is already there. */
                        spinlock_unlock(&cmd_lock);
                        return false;
                }

                /* Avoid deadlock. */
                if (hlp < cmd) {
                        spinlock_lock(&hlp->lock);
                        spinlock_lock(&cmd->lock);
                } else {
                        spinlock_lock(&cmd->lock);
                        spinlock_lock(&hlp->lock);
                }

                if (str_cmp(hlp->name, cmd->name) == 0) {
                        /* The command is already there. */
                        spinlock_unlock(&hlp->lock);
                        spinlock_unlock(&cmd->lock);
                        spinlock_unlock(&cmd_lock);
                        return false;
                }

                spinlock_unlock(&hlp->lock);
                spinlock_unlock(&cmd->lock);
        }

        /*
         * Now the command can be added.
         */
        list_append(&cmd->link, &cmd_list);

        spinlock_unlock(&cmd_lock);
        return true;
}

/** Print count times a character */
_NO_TRACE static void print_cc(char ch, size_t count)
{
        // FIXME: only lock once

        for (size_t i = 0; i < count; i++)
                putstr(&ch, 1);
}

/** Try to find a command beginning with prefix */
const char *cmdtab_enum(const char *name, const char **h, void **ctx)
{
        link_t **startpos = (link_t **) ctx;
        size_t namelen = str_length(name);

        spinlock_lock(&cmd_lock);

        if (*startpos == NULL)
                *startpos = list_first(&cmd_list);

        for (; *startpos != NULL; *startpos = list_next(*startpos, &cmd_list)) {
                cmd_info_t *hlp = list_get_instance(*startpos, cmd_info_t, link);

                const char *curname = hlp->name;
                if (str_length(curname) < namelen)
                        continue;

                if (str_lcmp(curname, name, namelen) == 0) {
                        *startpos = list_next(*startpos, &cmd_list);
                        if (h)
                                *h = hlp->description;

                        spinlock_unlock(&cmd_lock);
                        return (curname + str_lsize(curname, namelen));
                }
        }

        spinlock_unlock(&cmd_lock);
        return NULL;
}

/** Command completion of the commands
 *
 * @param name String to match, changed to hint on exit
 * @param size Input buffer size
 *
 * @return Number of found matches
 *
 */
_NO_TRACE static int cmdtab_compl(char *input, size_t size, indev_t *indev,
    hints_enum_func_t hints_enum)
{
        const char *name = input;

        size_t found = 0;

        /*
         * Maximum Match Length: Length of longest matching common
         * substring in case more than one match is found.
         */
        size_t max_match_len = size;
        size_t max_match_len_tmp = size;
        void *pos = NULL;
        const char *hint;
        const char *help;
        size_t hints_to_show = MAX_TAB_HINTS - 1;
        size_t total_hints_shown = 0;
        bool continue_showing_hints = true;

        char *output = malloc(MAX_CMDLINE);
        if (!output) {
                // TODO: fix the function so that it does not need allocation
                printf("Can't complete command, out of memory.\n");
                return 0;
        }

        output[0] = 0;

        while ((hint = hints_enum(name, NULL, &pos))) {
                if ((found == 0) || (str_length(hint) > str_length(output)))
                        str_cpy(output, MAX_CMDLINE, hint);

                found++;
        }

        /*
         * If the number of possible completions is more than MAX_TAB_HINTS,
         * ask the user whether to display them or not.
         */
        if (found > MAX_TAB_HINTS) {
                printf("\n");
                continue_showing_hints =
                    console_prompt_display_all_hints(indev, found);
        }

        if ((found > 1) && (str_length(output) != 0)) {
                printf("\n");
                pos = NULL;
                while ((hint = hints_enum(name, &help, &pos))) {

                        if (continue_showing_hints) {
                                if (help)
                                        printf("%s%s (%s)\n", name, hint, help);
                                else
                                        printf("%s%s\n", name, hint);

                                --hints_to_show;
                                ++total_hints_shown;

                                if ((hints_to_show == 0) && (total_hints_shown != found)) {
                                        /* Ask user to continue */
                                        continue_showing_hints =
                                            console_prompt_more_hints(indev, &hints_to_show);
                                }
                        }

                        max_match_len_tmp = 0;
                        while ((output[max_match_len_tmp] ==
                            hint[max_match_len_tmp]) &&
                            (max_match_len_tmp < max_match_len))
                                ++max_match_len_tmp;

                        max_match_len = max_match_len_tmp;
                }

                /* Keep only the characters common in all completions */
                output[max_match_len] = 0;
        }

        if (found > 0)
                str_cpy(input, size, output);

        free(output);
        return found;
}

_NO_TRACE static cmd_info_t *parse_cmd(const char32_t *cmdline)
{
        size_t start = 0;
        size_t end;
        char *tmp;

        while (isspace(cmdline[start]))
                start++;

        end = start + 1;

        while (!isspace(cmdline[end]))
                end++;

        tmp = malloc(STR_BOUNDS(end - start + 1));
        if (!tmp)
                return NULL;

        wstr_to_str(tmp, end - start + 1, &cmdline[start]);

        spinlock_lock(&cmd_lock);

        list_foreach(cmd_list, link, cmd_info_t, hlp) {
                spinlock_lock(&hlp->lock);

                if (str_cmp(hlp->name, tmp) == 0) {
                        spinlock_unlock(&hlp->lock);
                        spinlock_unlock(&cmd_lock);
                        free(tmp);
                        return hlp;
                }

                spinlock_unlock(&hlp->lock);
        }

        free(tmp);
        spinlock_unlock(&cmd_lock);

        return NULL;
}

_NO_TRACE static char32_t *clever_readline(const char *prompt, indev_t *indev,
    char *tmp)
{
        printf("%s> ", prompt);

        size_t position = 0;
        char32_t *current = history[history_pos];
        current[0] = 0;

        while (true) {
                char32_t ch = indev_pop_character(indev);

                if (ch == '\n') {
                        /* Enter */
                        putstr("\n", 1);
                        break;
                }

                if (ch == '\b') {
                        /* Backspace */
                        if (position == 0)
                                continue;

                        if (wstr_remove(current, position - 1)) {
                                position--;
                                putstr("\b", 1);
                                printf("%ls ", current + position);
                                print_cc('\b', wstr_length(current) - position + 1);
                                continue;
                        }
                }

                if (ch == '\t') {
                        /* Tab completion */

                        size_t i = position;
                        while (current[i] && !isspace(current[i]))
                                i++;

                        char32_t stash = current[i];
                        current[i] = 0;
                        printf("%ls", &current[position]);
                        current[i] = stash;
                        position = i;

                        /*
                         * Find the beginning of the word
                         * and copy it to tmp
                         */
                        size_t beg;
                        unsigned narg = 0;
                        if (position == 0) {
                                tmp[0] = '\0';
                                beg = 0;
                        } else {
                                beg = position - 1;
                                while ((beg > 0) && (!isspace(current[beg])))
                                        beg--;

                                if (isspace(current[beg]))
                                        beg++;

                                wstr_to_str(tmp, position - beg + 1, current + beg);
                        }

                        /* Count which argument number are we tabbing (narg=0 is cmd) */
                        bool sp = false;
                        for (; beg > 0; beg--) {
                                if (isspace(current[beg])) {
                                        if (!sp) {
                                                narg++;
                                                sp = true;
                                        }
                                } else
                                        sp = false;
                        }

                        if (narg && isspace(current[0]))
                                narg--;

                        int found;
                        if (narg == 0) {
                                /* Command completion */
                                found = cmdtab_compl(tmp, STR_BOUNDS(MAX_CMDLINE), indev,
                                    cmdtab_enum);
                        } else {
                                /* Arguments completion */
                                cmd_info_t *cmd = parse_cmd(current);
                                if (!cmd || !cmd->hints_enum || cmd->argc < narg)
                                        continue;
                                found = cmdtab_compl(tmp, STR_BOUNDS(MAX_CMDLINE), indev,
                                    cmd->hints_enum);
                        }

                        if (found == 0)
                                continue;

                        /*
                         * We have hints, possibly many. In case of more than one hint,
                         * tmp will contain the common prefix.
                         */
                        size_t off = 0;
                        for (size_t i = 0; (ch = str_decode(tmp, &off, STR_NO_LIMIT)); i++)
                                if (!wstr_linsert(current, ch, position + i, MAX_CMDLINE))
                                        break;

                        if (found > 1) {
                                /* No unique hint, list was printed */
                                printf("%s> ", prompt);
                                printf("%ls", current);
                                position += str_length(tmp);
                                print_cc('\b', wstr_length(current) - position);
                                continue;
                        }

                        /* We have a hint */

                        printf("%ls", current + position);
                        position += str_length(tmp);
                        print_cc('\b', wstr_length(current) - position);

                        if (position == wstr_length(current)) {
                                /* Insert a space after the last completed argument */
                                if (wstr_linsert(current, ' ', position, MAX_CMDLINE)) {
                                        printf("%ls", current + position);
                                        position++;
                                }
                        }
                        continue;
                }

                if (ch == U_LEFT_ARROW) {
                        /* Left */
                        if (position > 0) {
                                putstr("\b", 1);
                                position--;
                        }
                        continue;
                }

                if (ch == U_RIGHT_ARROW) {
                        /* Right */
                        if (position < wstr_length(current)) {
                                printf("%lc", current[position]);
                                position++;
                        }
                        continue;
                }

                if ((ch == U_UP_ARROW) || (ch == U_DOWN_ARROW)) {
                        /* Up, down */
                        print_cc('\b', position);
                        print_cc(' ', wstr_length(current));
                        print_cc('\b', wstr_length(current));

                        if (ch == U_UP_ARROW) {
                                /* Up */
                                if (history_pos == 0)
                                        history_pos = KCONSOLE_HISTORY - 1;
                                else
                                        history_pos--;
                        } else {
                                /* Down */
                                history_pos++;
                                history_pos = history_pos % KCONSOLE_HISTORY;
                        }
                        current = history[history_pos];
                        printf("%ls", current);
                        position = wstr_length(current);
                        continue;
                }

                if (ch == U_HOME_ARROW) {
                        /* Home */
                        print_cc('\b', position);
                        position = 0;
                        continue;
                }

                if (ch == U_END_ARROW) {
                        /* End */
                        printf("%ls", current + position);
                        position = wstr_length(current);
                        continue;
                }

                if (ch == U_DELETE) {
                        /* Delete */
                        if (position == wstr_length(current))
                                continue;

                        if (wstr_remove(current, position)) {
                                printf("%ls ", current + position);
                                print_cc('\b', wstr_length(current) - position + 1);
                        }
                        continue;
                }

                if (wstr_linsert(current, ch, position, MAX_CMDLINE)) {
                        printf("%ls", current + position);
                        position++;
                        print_cc('\b', wstr_length(current) - position);
                }
        }

        if (wstr_length(current) > 0) {
                history_pos++;
                history_pos = history_pos % KCONSOLE_HISTORY;
        }

        return current;
}

bool kconsole_check_poll(void)
{
        return check_poll(stdin);
}

_NO_TRACE static bool parse_int_arg(const char *text, size_t len,
    sysarg_t *result)
{
        bool isaddr = false;
        bool isptr = false;

        /* If we get a name, try to find it in symbol table */
        if (text[0] == '&') {
                isaddr = true;
                text++;
                len--;
        } else if (text[0] == '*') {
                isptr = true;
                text++;
                len--;
        }

        if ((text[0] < '0') || (text[0] > '9')) {
                char symname[MAX_SYMBOL_NAME];
                str_ncpy(symname, MAX_SYMBOL_NAME, text, len + 1);

                uintptr_t symaddr;
                errno_t rc = symtab_addr_lookup(symname, &symaddr);
                switch (rc) {
                case ENOENT:
                        printf("Symbol %s not found.\n", symname);
                        return false;
                case EOVERFLOW:
                        printf("Duplicate symbol %s.\n", symname);
                        symtab_print_search(symname);
                        return false;
                case ENOTSUP:
                        printf("No symbol information available.\n");
                        return false;
                case EOK:
                        if (isaddr)
                                *result = (sysarg_t) symaddr;
                        else if (isptr)
                                *result = **((sysarg_t **) symaddr);
                        else
                                *result = *((sysarg_t *) symaddr);
                        break;
                default:
                        printf("Unknown error.\n");
                        return false;
                }
        } else {
                /* It's a number - convert it */
                uint64_t value;
                const char *end;
                errno_t rc = str_uint64_t(text, &end, 0, false, &value);
                if (end != text + len)
                        rc = EINVAL;
                switch (rc) {
                case EINVAL:
                        printf("Invalid number '%s'.\n", text);
                        return false;
                case EOVERFLOW:
                        printf("Integer overflow in '%s'.\n", text);
                        return false;
                case EOK:
                        *result = (sysarg_t) value;
                        if (isptr)
                                *result = *((sysarg_t *) *result);
                        break;
                default:
                        printf("Unknown error parsing '%s'.\n", text);
                        return false;
                }
        }

        return true;
}

/** Parse argument.
 *
 * Find start and end positions of command line argument.
 *
 * @param cmdline Command line as read from the input device.
 * @param size    Size (in bytes) of the string.
 * @param start   On entry, 'start' contains pointer to the offset
 *                of the first unprocessed character of cmdline.
 *                On successful exit, it marks beginning of the next argument.
 * @param end     Undefined on entry. On exit, 'end' is the offset of the first
 *                character behind the next argument.
 *
 * @return False on failure, true on success.
 *
 */
_NO_TRACE static bool parse_argument(const char *cmdline, size_t size,
    size_t *start, size_t *end)
{
        assert(start != NULL);
        assert(end != NULL);

        bool found_start = false;
        size_t offset = *start;
        size_t prev = *start;
        char32_t ch;

        while ((ch = str_decode(cmdline, &offset, size)) != 0) {
                if (!found_start) {
                        if (!isspace(ch)) {
                                *start = prev;
                                found_start = true;
                        }
                } else {
                        if (isspace(ch))
                                break;
                }

                prev = offset;
        }
        *end = prev;

        return found_start;
}

/** Parse command line.
 *
 * @param cmdline Command line as read from input device.
 * @param size    Size (in bytes) of the string.
 *
 * @return Structure describing the command.
 *
 */
_NO_TRACE static cmd_info_t *parse_cmdline(const char *cmdline, size_t size)
{
        size_t start = 0;
        size_t end = 0;
        if (!parse_argument(cmdline, size, &start, &end)) {
                /* Command line did not contain alphanumeric word. */
                return NULL;
        }
        spinlock_lock(&cmd_lock);

        cmd_info_t *cmd = NULL;

        list_foreach(cmd_list, link, cmd_info_t, hlp) {
                spinlock_lock(&hlp->lock);

                if (str_lcmp(hlp->name, cmdline + start,
                    max(str_length(hlp->name),
                    str_nlength(cmdline + start, (size_t) (end - start)))) == 0) {
                        cmd = hlp;
                        break;
                }

                spinlock_unlock(&hlp->lock);
        }

        spinlock_unlock(&cmd_lock);

        if (!cmd) {
                /* Unknown command. */
                printf("Unknown command.\n");
                return NULL;
        }

        /* cmd == hlp is locked */

        /*
         * The command line must be further analyzed and
         * the parameters therefrom must be matched and
         * converted to those specified in the cmd info
         * structure.
         */

        bool error = false;
        size_t i;
        for (i = 0; i < cmd->argc; i++) {
                char *buf;

                start = end;
                if (!parse_argument(cmdline, size, &start, &end)) {
                        if (cmd->argv[i].type == ARG_TYPE_STRING_OPTIONAL) {
                                buf = (char *) cmd->argv[i].buffer;
                                str_cpy(buf, cmd->argv[i].len, "");
                                continue;
                        }

                        printf("Too few arguments.\n");
                        spinlock_unlock(&cmd->lock);
                        return NULL;
                }

                switch (cmd->argv[i].type) {
                case ARG_TYPE_STRING:
                case ARG_TYPE_STRING_OPTIONAL:
                        buf = (char *) cmd->argv[i].buffer;
                        str_ncpy(buf, cmd->argv[i].len, cmdline + start,
                            end - start);
                        break;
                case ARG_TYPE_INT:
                        if (!parse_int_arg(cmdline + start, end - start,
                            &cmd->argv[i].intval))
                                error = true;
                        break;
                case ARG_TYPE_VAR:
                        if ((start < end - 1) && (cmdline[start] == '"')) {
                                if (cmdline[end - 1] == '"') {
                                        buf = (char *) cmd->argv[i].buffer;
                                        str_ncpy(buf, cmd->argv[i].len,
                                            cmdline + start + 1,
                                            (end - start) - 1);
                                        cmd->argv[i].intval = (sysarg_t) buf;
                                        cmd->argv[i].vartype = ARG_TYPE_STRING;
                                } else {
                                        printf("Wrong syntax.\n");
                                        error = true;
                                }
                        } else if (parse_int_arg(cmdline + start,
                            end - start, &cmd->argv[i].intval)) {
                                cmd->argv[i].vartype = ARG_TYPE_INT;
                        } else {
                                printf("Unrecognized variable argument.\n");
                                error = true;
                        }
                        break;
                case ARG_TYPE_INVALID:
                default:
                        printf("Invalid argument type\n");
                        error = true;
                        break;
                }
        }

        if (error) {
                spinlock_unlock(&cmd->lock);
                return NULL;
        }

        start = end;
        if (parse_argument(cmdline, size, &start, &end)) {
                printf("Too many arguments.\n");
                spinlock_unlock(&cmd->lock);
                return NULL;
        }

        spinlock_unlock(&cmd->lock);
        return cmd;
}

/** Kernel console prompt.
 *
 * @param prompt Kernel console prompt (e.g kconsole/panic).
 * @param msg    Message to display in the beginning.
 * @param kcon   Wait for keypress to show the prompt
 *               and never exit.
 *
 */
void kconsole(const char *prompt, const char *msg, bool kcon)
{
        if (!stdin) {
                LOG("No stdin for kernel console");
                return;
        }

        if (msg)
                printf("%s", msg);

        if (kcon)
                indev_pop_character(stdin);
        else
                printf("Type \"exit\" to leave the console.\n");

        char *buffer = malloc(STR_BOUNDS(MAX_CMDLINE));
        char *cmdline = malloc(STR_BOUNDS(MAX_CMDLINE));
        if (!buffer || !cmdline) {
                // TODO: fix the function so that it does not need allocations
                printf("Can't start console, out of memory.\n");
                free(buffer);
                free(cmdline);
                return;
        }

        while (true) {
                char32_t *tmp = clever_readline((char *) prompt, stdin, buffer);
                size_t len = wstr_length(tmp);
                if (!len)
                        continue;

                wstr_to_str(cmdline, STR_BOUNDS(MAX_CMDLINE), tmp);

                if ((!kcon) && (len == 4) && (str_lcmp(cmdline, "exit", 4) == 0))
                        break;

                cmd_info_t *cmd_info = parse_cmdline(cmdline, STR_BOUNDS(MAX_CMDLINE));
                if (!cmd_info)
                        continue;

                (void) cmd_info->func(cmd_info->argv);
        }
        free(buffer);
        free(cmdline);
}

/** Kernel console managing thread.
 *
 */
void kconsole_thread(void *data)
{
        kconsole("kconsole", "Kernel console ready (press any key to activate)\n", true);
}

/** @}
 */