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/*
 * 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 genericconsole
 * @{
 */

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

#include <console/kconsole.h>
#include <console/console.h>
#include <console/chardev.h>
#include <console/cmd.h>
#include <print.h>
#include <panic.h>
#include <arch/types.h>
#include <adt/list.h>
#include <arch.h>
#include <macros.h>
#include <debug.h>
#include <func.h>
#include <symtab.h>
#include <macros.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_head);  /**< Command list. */

static cmd_info_t *parse_cmdline(char *cmdline, size_t len);
static bool parse_argument(char *cmdline, size_t len, index_t *start,
    index_t *end);
static char history[KCONSOLE_HISTORY][MAX_CMDLINE] = {};

/** Initialize kconsole data structures. */
void kconsole_init(void)
{
    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 0 on failure, 1 on success.
 */
int cmd_register(cmd_info_t *cmd)
{
    link_t *cur;
    
    spinlock_lock(&cmd_lock);
    
    /*
     * Make sure the command is not already listed.
     */
    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {
        cmd_info_t *hlp;
        
        hlp = list_get_instance(cur, cmd_info_t, link);

        if (hlp == cmd) {
            /* The command is already there. */
            spinlock_unlock(&cmd_lock);
            return 0;
        }

        /* Avoid deadlock. */
        if (hlp < cmd) {
            spinlock_lock(&hlp->lock);
            spinlock_lock(&cmd->lock);
        } else {
            spinlock_lock(&cmd->lock);
            spinlock_lock(&hlp->lock);
        }
        if ((strncmp(hlp->name, cmd->name, max(strlen(cmd->name),
            strlen(hlp->name))) == 0)) {
            /* The command is already there. */
            spinlock_unlock(&hlp->lock);
            spinlock_unlock(&cmd->lock);
            spinlock_unlock(&cmd_lock);
            return 0;
        }
        
        spinlock_unlock(&hlp->lock);
        spinlock_unlock(&cmd->lock);
    }
    
    /*
     * Now the command can be added.
     */
    list_append(&cmd->link, &cmd_head);
    
    spinlock_unlock(&cmd_lock);
    return 1;
}

/** Print count times a character */
static void rdln_print_c(char ch, int count)
{
    int i;
    for (i = 0; i < count; i++)
        putchar(ch);
}

/** Insert character to string */
static void insert_char(char *str, char ch, int pos)
{
    int i;
    
    for (i = strlen(str); i > pos; i--)
        str[i] = str[i - 1];
    str[pos] = ch;
}

/** Try to find a command beginning with prefix */
static const char *cmdtab_search_one(const char *name,link_t **startpos)
{
    size_t namelen = strlen(name);
    const char *curname;

    spinlock_lock(&cmd_lock);

    if (!*startpos)
        *startpos = cmd_head.next;

    for (; *startpos != &cmd_head; *startpos = (*startpos)->next) {
        cmd_info_t *hlp;
        hlp = list_get_instance(*startpos, cmd_info_t, link);

        curname = hlp->name;
        if (strlen(curname) < namelen)
            continue;
        if (strncmp(curname, name, namelen) == 0) {
            spinlock_unlock(&cmd_lock); 
            return curname+namelen;
        }
    }
    spinlock_unlock(&cmd_lock); 
    return NULL;
}


/** Command completion of the commands 
 *
 * @param name - string to match, changed to hint on exit
 * @return number of found matches
 */
static int cmdtab_compl(char *name)
{
    static char output[MAX_SYMBOL_NAME + 1];
    link_t *startpos = NULL;
    const char *foundtxt;
    int found = 0;
    int i;

    output[0] = '\0';
    while ((foundtxt = cmdtab_search_one(name, &startpos))) {
        startpos = startpos->next;
        if (!found)
            strncpy(output, foundtxt, strlen(foundtxt) + 1);
        else {
            for (i = 0; output[i] && foundtxt[i] &&
                output[i] == foundtxt[i]; i++)
                ;
            output[i] = '\0';
        }
        found++;
    }
    if (!found)
        return 0;

    if (found > 1 && !strlen(output)) {
        printf("\n");
        startpos = NULL;
        while ((foundtxt = cmdtab_search_one(name, &startpos))) {
            cmd_info_t *hlp;
            hlp = list_get_instance(startpos, cmd_info_t, link);
            printf("%s - %s\n", hlp->name, hlp->description);
            startpos = startpos->next;
        }
    }
    strncpy(name, output, MAX_SYMBOL_NAME);
    return found;
    
}

//char *clever_readline(const char *prompt, chardev_t *input);
static char *clever_readline(const char *prompt, chardev_t *input)
{
    static int histposition = 0;

    static char tmp[MAX_CMDLINE + 1];
    int curlen = 0, position = 0;
    char *current = history[histposition];
    int i;
    char mod; /* Command Modifier */
    char c;

    printf("%s> ", prompt);
    while (1) {
        c = _getc(input);
        if (c == '\n') {
            putchar(c);
            break;
        }
        if (c == '\b') { /* Backspace */
            if (position == 0)
                continue;
            for (i = position; i < curlen; i++)
                current[i - 1] = current[i];
            curlen--;
            position--;
            putchar('\b');
            for (i = position; i < curlen; i++)
                putchar(current[i]);
            putchar(' ');
            rdln_print_c('\b', curlen - position + 1);
            continue;
        }
        if (c == '\t') { /* Tabulator */
            int found;

            /* Move to the end of the word */
            for (; position < curlen && current[position] != ' ';
                position++)
                putchar(current[position]);
            /* Copy to tmp last word */
            for (i = position - 1; i >= 0 && current[i] != ' '; i--)
                ;
            /* If word begins with * or &, skip it */
            if (tmp[0] == '*' || tmp[0] == '&')
                for (i = 1; tmp[i]; i++)
                    tmp[i - 1] = tmp[i];
            i++; /* I is at the start of the word */
            strncpy(tmp, current + i, position - i + 1);

            if (i == 0) { /* Command completion */
                found = cmdtab_compl(tmp);
            } else { /* Symtab completion */
                found = symtab_compl(tmp);
            }

            if (found == 0) 
                continue;
            for (i = 0; tmp[i] && curlen < MAX_CMDLINE;
                i++, curlen++)
                insert_char(current, tmp[i], i + position);

            if (strlen(tmp) || found == 1) { /* If we have a hint */
                for (i = position; i < curlen; i++) 
                    putchar(current[i]);
                position += strlen(tmp);
                /* Add space to end */
                if (found == 1 && position == curlen &&
                    curlen < MAX_CMDLINE) {
                    current[position] = ' ';
                    curlen++;
                    position++;
                    putchar(' ');
                }
            } else { /* No hint, table was printed */
                printf("%s> ", prompt);
                for (i = 0; i < curlen; i++)
                    putchar(current[i]);
                position += strlen(tmp);
            }
            rdln_print_c('\b', curlen - position);
            continue;
        }
        if (c == 0x1b) { /* Special command */
            mod = _getc(input);
            c = _getc(input);

            if (mod != 0x5b && mod != 0x4f)
                continue;

            if (c == 0x33 && _getc(input) == 0x7e) {
                /* Delete */
                if (position == curlen)
                    continue;
                for (i = position + 1; i < curlen; i++) {
                    putchar(current[i]);
                    current[i - 1] = current[i];
                }
                putchar(' ');
                rdln_print_c('\b', curlen - position);
                curlen--;
            } else if (c == 0x48) { /* Home */
                rdln_print_c('\b', position);
                position = 0;
            } else if (c == 0x46) {  /* End */
                for (i = position; i < curlen; i++)
                    putchar(current[i]);
                position = curlen;
            } else if (c == 0x44) { /* Left */
                if (position > 0) {
                    putchar('\b');
                    position--;
                }
                continue;
            } else if (c == 0x43) { /* Right */
                if (position < curlen) {
                    putchar(current[position]);
                    position++;
                }
                continue;
            } else if (c == 0x41 || c == 0x42) { 
                                /* Up, down */
                rdln_print_c('\b', position);
                rdln_print_c(' ', curlen);
                rdln_print_c('\b', curlen);
                if (c == 0x41) /* Up */
                    histposition--;
                else
                    histposition++;
                if (histposition < 0) {
                    histposition = KCONSOLE_HISTORY - 1;
                } else {
                    histposition =
                        histposition % KCONSOLE_HISTORY;
                }
                current = history[histposition];
                printf("%s", current);
                curlen = strlen(current);
                position = curlen;
                continue;
            }
            continue;
        }
        if (curlen >= MAX_CMDLINE)
            continue;

        insert_char(current, c, position);

        curlen++;
        for (i = position; i < curlen; i++)
            putchar(current[i]);
        position++;
        rdln_print_c('\b',curlen - position);
    } 
    if (curlen) {
        histposition++;
        histposition = histposition % KCONSOLE_HISTORY;
    }
    current[curlen] = '\0';
    return current;
}

/** Kernel console managing thread.
 *
 * @param prompt Kernel console prompt (e.g kconsole/panic).
 */
void kconsole(void *prompt)
{
    cmd_info_t *cmd_info;
    count_t len;
    char *cmdline;

    if (!stdin) {
        printf("%s: no stdin\n", __func__);
        return;
    }
    
    while (true) {
        cmdline = clever_readline((char *) prompt, stdin);
        len = strlen(cmdline);
        if (!len)
            continue;
        cmd_info = parse_cmdline(cmdline, len);
        if (!cmd_info)
            continue;
        if (strncmp(cmd_info->name, "exit",
            min(strlen(cmd_info->name), 5)) == 0)
            break;
        (void) cmd_info->func(cmd_info->argv);
    }
}

static int parse_int_arg(char *text, size_t len, unative_t *result)
{
    static char symname[MAX_SYMBOL_NAME];
    uintptr_t symaddr;
    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') {
        strncpy(symname, text, min(len + 1, MAX_SYMBOL_NAME));
        symaddr = get_symbol_addr(symname);
        if (!symaddr) {
            printf("Symbol %s not found.\n", symname);
            return -1;
        }
        if (symaddr == (uintptr_t) -1) {
            printf("Duplicate symbol %s.\n", symname);
            symtab_print_search(symname);
            return -1;
        }
        if (isaddr)
            *result = (unative_t)symaddr;
        else if (isptr)
            *result = **((unative_t **)symaddr);
        else
            *result = *((unative_t *)symaddr);
    } else { /* It's a number - convert it */
        *result = atoi(text);
        if (isptr)
            *result = *((unative_t *)*result);
    }

    return 0;
}

/** Parse command line.
 *
 * @param cmdline Command line as read from input device.
 * @param len Command line length.
 *
 * @return Structure describing the command.
 */
cmd_info_t *parse_cmdline(char *cmdline, size_t len)
{
    index_t start = 0, end = 0;
    cmd_info_t *cmd = NULL;
    link_t *cur;
    count_t i;
    int error = 0;
    
    if (!parse_argument(cmdline, len, &start, &end)) {
        /* Command line did not contain alphanumeric word. */
        return NULL;
    }

    spinlock_lock(&cmd_lock);
    
    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {
        cmd_info_t *hlp;
        
        hlp = list_get_instance(cur, cmd_info_t, link);
        spinlock_lock(&hlp->lock);
        
        if (strncmp(hlp->name, &cmdline[start], max(strlen(hlp->name),
            end - start + 1)) == 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.
     */

    for (i = 0; i < cmd->argc; i++) {
        char *buf;
        start = end + 1;
        if (!parse_argument(cmdline, len, &start, &end)) {
            printf("Too few arguments.\n");
            spinlock_unlock(&cmd->lock);
            return NULL;
        }
        
        error = 0;
        switch (cmd->argv[i].type) {
        case ARG_TYPE_STRING:
            buf = (char *) cmd->argv[i].buffer;
            strncpy(buf, (const char *) &cmdline[start],
                min((end - start) + 2, cmd->argv[i].len));
            buf[min((end - start) + 1, cmd->argv[i].len - 1)] =
                '\0';
            break;
        case ARG_TYPE_INT: 
            if (parse_int_arg(cmdline + start, end - start + 1, 
                &cmd->argv[i].intval))
                error = 1;
            break;
        case ARG_TYPE_VAR:
            if (start != end && cmdline[start] == '"' &&
                cmdline[end] == '"') {
                buf = (char *) cmd->argv[i].buffer;
                strncpy(buf, (const char *) &cmdline[start + 1],
                    min((end-start), cmd->argv[i].len));
                buf[min((end - start), cmd->argv[i].len - 1)] =
                    '\0';
                cmd->argv[i].intval = (unative_t) buf;
                cmd->argv[i].vartype = ARG_TYPE_STRING;
            } else if (!parse_int_arg(cmdline + start,
                end - start + 1, &cmd->argv[i].intval)) {
                cmd->argv[i].vartype = ARG_TYPE_INT;
            } else {
                printf("Unrecognized variable argument.\n");
                error = 1;
            }
            break;
        case ARG_TYPE_INVALID:
        default:
            printf("invalid argument type\n");
            error = 1;
            break;
        }
    }
    
    if (error) {
        spinlock_unlock(&cmd->lock);
        return NULL;
    }
    
    start = end + 1;
    if (parse_argument(cmdline, len, &start, &end)) {
        printf("Too many arguments.\n");
        spinlock_unlock(&cmd->lock);
        return NULL;
    }
    
    spinlock_unlock(&cmd->lock);
    return cmd;
}

/** Parse argument.
 *
 * Find start and end positions of command line argument.
 *
 * @param cmdline Command line as read from the input device.
 * @param len Number of characters in cmdline.
 * @param start On entry, 'start' contains pointer to the index 
 *        of first unprocessed character of cmdline.
 *        On successful exit, it marks beginning of the next argument.
 * @param end Undefined on entry. On exit, 'end' points to the last character
 *        of the next argument.
 *
 * @return false on failure, true on success.
 */
bool parse_argument(char *cmdline, size_t len, index_t *start, index_t *end)
{
    index_t i;
    bool found_start = false;
    
    ASSERT(start != NULL);
    ASSERT(end != NULL);
    
    for (i = *start; i < len; i++) {
        if (!found_start) {
            if (isspace(cmdline[i]))
                (*start)++;
            else
                found_start = true;
        } else {
            if (isspace(cmdline[i]))
                break;
        }
    }
    *end = i - 1;

    return found_start;
}

/** @}
 */