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  1. /*
  2.  * Copyright (c) 2005 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericconsole
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file    kconsole.c
  35.  * @brief   Kernel console.
  36.  *
  37.  * This file contains kernel thread managing the kernel console.
  38.  */
  39.  
  40. #include <console/kconsole.h>
  41. #include <console/console.h>
  42. #include <console/chardev.h>
  43. #include <console/cmd.h>
  44. #include <print.h>
  45. #include <panic.h>
  46. #include <arch/types.h>
  47. #include <adt/list.h>
  48. #include <arch.h>
  49. #include <macros.h>
  50. #include <debug.h>
  51. #include <func.h>
  52. #include <string.h>
  53. #include <symtab.h>
  54. #include <macros.h>
  55. #include <sysinfo/sysinfo.h>
  56. #include <ddi/device.h>
  57.  
  58. /** Simple kernel console.
  59.  *
  60.  * The console is realized by kernel thread kconsole.
  61.  * It doesn't understand any useful command on its own,
  62.  * but makes it possible for other kernel subsystems to
  63.  * register their own commands.
  64.  */
  65.  
  66. /** Locking.
  67.  *
  68.  * There is a list of cmd_info_t structures. This list
  69.  * is protected by cmd_lock spinlock. Note that specially
  70.  * the link elements of cmd_info_t are protected by
  71.  * this lock.
  72.  *
  73.  * Each cmd_info_t also has its own lock, which protects
  74.  * all elements thereof except the link element.
  75.  *
  76.  * cmd_lock must be acquired before any cmd_info lock.
  77.  * When locking two cmd info structures, structure with
  78.  * lower address must be locked first.
  79.  */
  80.  
  81. SPINLOCK_INITIALIZE(cmd_lock);  /**< Lock protecting command list. */
  82. LIST_INITIALIZE(cmd_head);  /**< Command list. */
  83.  
  84. static cmd_info_t *parse_cmdline(char *cmdline, size_t len);
  85. static bool parse_argument(char *cmdline, size_t len, index_t *start,
  86.     index_t *end);
  87. static char history[KCONSOLE_HISTORY][MAX_CMDLINE] = {};
  88.  
  89. /*
  90.  * For now, we use 0 as INR.
  91.  * However, it is therefore desirable to have architecture specific
  92.  * definition of KCONSOLE_VIRT_INR in the future.
  93.  */
  94. #define KCONSOLE_VIRT_INR  0
  95.  
  96. bool kconsole_notify = false;
  97. irq_t kconsole_irq;
  98.  
  99.  
  100. /** Allways refuse IRQ ownership.
  101.  *
  102.  * This is not a real IRQ, so we always decline.
  103.  *
  104.  * @return Always returns IRQ_DECLINE.
  105.  *
  106.  */
  107. static irq_ownership_t kconsole_claim(irq_t *irq)
  108. {
  109.     return IRQ_DECLINE;
  110. }
  111.  
  112.  
  113. /** Initialize kconsole data structures
  114.  *
  115.  * This is the most basic initialization, almost no
  116.  * other kernel subsystem is ready yet.
  117.  *
  118.  */
  119. void kconsole_init(void)
  120. {
  121.     unsigned int i;
  122.  
  123.     cmd_init();
  124.     for (i = 0; i < KCONSOLE_HISTORY; i++)
  125.         history[i][0] = '\0';
  126. }
  127.  
  128.  
  129. /** Initialize kconsole notification mechanism
  130.  *
  131.  * Initialize the virtual IRQ notification mechanism.
  132.  *
  133.  */
  134. void kconsole_notify_init(void)
  135. {
  136.     devno_t devno = device_assign_devno();
  137.    
  138.     sysinfo_set_item_val("kconsole.present", NULL, true);
  139.     sysinfo_set_item_val("kconsole.devno", NULL, devno);
  140.     sysinfo_set_item_val("kconsole.inr", NULL, KCONSOLE_VIRT_INR);
  141.    
  142.     irq_initialize(&kconsole_irq);
  143.     kconsole_irq.devno = devno;
  144.     kconsole_irq.inr = KCONSOLE_VIRT_INR;
  145.     kconsole_irq.claim = kconsole_claim;
  146.     irq_register(&kconsole_irq);
  147.    
  148.     kconsole_notify = true;
  149. }
  150.  
  151.  
  152. /** Register kconsole command.
  153.  *
  154.  * @param cmd Structure describing the command.
  155.  *
  156.  * @return 0 on failure, 1 on success.
  157.  */
  158. int cmd_register(cmd_info_t *cmd)
  159. {
  160.     link_t *cur;
  161.    
  162.     spinlock_lock(&cmd_lock);
  163.    
  164.     /*
  165.      * Make sure the command is not already listed.
  166.      */
  167.     for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {
  168.         cmd_info_t *hlp;
  169.        
  170.         hlp = list_get_instance(cur, cmd_info_t, link);
  171.  
  172.         if (hlp == cmd) {
  173.             /* The command is already there. */
  174.             spinlock_unlock(&cmd_lock);
  175.             return 0;
  176.         }
  177.  
  178.         /* Avoid deadlock. */
  179.         if (hlp < cmd) {
  180.             spinlock_lock(&hlp->lock);
  181.             spinlock_lock(&cmd->lock);
  182.         } else {
  183.             spinlock_lock(&cmd->lock);
  184.             spinlock_lock(&hlp->lock);
  185.         }
  186.         if ((strncmp(hlp->name, cmd->name, max(strlen(cmd->name),
  187.             strlen(hlp->name))) == 0)) {
  188.             /* The command is already there. */
  189.             spinlock_unlock(&hlp->lock);
  190.             spinlock_unlock(&cmd->lock);
  191.             spinlock_unlock(&cmd_lock);
  192.             return 0;
  193.         }
  194.        
  195.         spinlock_unlock(&hlp->lock);
  196.         spinlock_unlock(&cmd->lock);
  197.     }
  198.    
  199.     /*
  200.      * Now the command can be added.
  201.      */
  202.     list_append(&cmd->link, &cmd_head);
  203.    
  204.     spinlock_unlock(&cmd_lock);
  205.     return 1;
  206. }
  207.  
  208. /** Print count times a character */
  209. static void rdln_print_c(char ch, int count)
  210. {
  211.     int i;
  212.     for (i = 0; i < count; i++)
  213.         putchar(ch);
  214. }
  215.  
  216. /** Insert character to string */
  217. static void insert_char(char *str, char ch, int pos)
  218. {
  219.     int i;
  220.    
  221.     for (i = strlen(str); i > pos; i--)
  222.         str[i] = str[i - 1];
  223.     str[pos] = ch;
  224. }
  225.  
  226. /** Try to find a command beginning with prefix */
  227. static const char *cmdtab_search_one(const char *name,link_t **startpos)
  228. {
  229.     size_t namelen = strlen(name);
  230.     const char *curname;
  231.  
  232.     spinlock_lock(&cmd_lock);
  233.  
  234.     if (!*startpos)
  235.         *startpos = cmd_head.next;
  236.  
  237.     for (; *startpos != &cmd_head; *startpos = (*startpos)->next) {
  238.         cmd_info_t *hlp;
  239.         hlp = list_get_instance(*startpos, cmd_info_t, link);
  240.  
  241.         curname = hlp->name;
  242.         if (strlen(curname) < namelen)
  243.             continue;
  244.         if (strncmp(curname, name, namelen) == 0) {
  245.             spinlock_unlock(&cmd_lock);
  246.             return curname+namelen;
  247.         }
  248.     }
  249.     spinlock_unlock(&cmd_lock);
  250.     return NULL;
  251. }
  252.  
  253.  
  254. /** Command completion of the commands
  255.  *
  256.  * @param name - string to match, changed to hint on exit
  257.  * @return number of found matches
  258.  */
  259. static int cmdtab_compl(char *name)
  260. {
  261.     static char output[MAX_SYMBOL_NAME + 1];
  262.     link_t *startpos = NULL;
  263.     const char *foundtxt;
  264.     int found = 0;
  265.     int i;
  266.  
  267.     output[0] = '\0';
  268.     while ((foundtxt = cmdtab_search_one(name, &startpos))) {
  269.         startpos = startpos->next;
  270.         if (!found)
  271.             strncpy(output, foundtxt, strlen(foundtxt) + 1);
  272.         else {
  273.             for (i = 0; output[i] && foundtxt[i] &&
  274.                 output[i] == foundtxt[i]; i++)
  275.                 ;
  276.             output[i] = '\0';
  277.         }
  278.         found++;
  279.     }
  280.     if (!found)
  281.         return 0;
  282.  
  283.     if (found > 1 && !strlen(output)) {
  284.         printf("\n");
  285.         startpos = NULL;
  286.         while ((foundtxt = cmdtab_search_one(name, &startpos))) {
  287.             cmd_info_t *hlp;
  288.             hlp = list_get_instance(startpos, cmd_info_t, link);
  289.             printf("%s - %s\n", hlp->name, hlp->description);
  290.             startpos = startpos->next;
  291.         }
  292.     }
  293.     strncpy(name, output, MAX_SYMBOL_NAME);
  294.     return found;
  295.    
  296. }
  297.  
  298. static char *clever_readline(const char *prompt, indev_t *input)
  299. {
  300.     static int histposition = 0;
  301.  
  302.     static char tmp[MAX_CMDLINE + 1];
  303.     int curlen = 0, position = 0;
  304.     char *current = history[histposition];
  305.     int i;
  306.     char mod; /* Command Modifier */
  307.     char c;
  308.  
  309.     printf("%s> ", prompt);
  310.     while (1) {
  311.         c = _getc(input);
  312.         if (c == '\n') {
  313.             putchar(c);
  314.             break;
  315.         }
  316.         if (c == '\b') { /* Backspace */
  317.             if (position == 0)
  318.                 continue;
  319.             for (i = position; i < curlen; i++)
  320.                 current[i - 1] = current[i];
  321.             curlen--;
  322.             position--;
  323.             putchar('\b');
  324.             for (i = position; i < curlen; i++)
  325.                 putchar(current[i]);
  326.             putchar(' ');
  327.             rdln_print_c('\b', curlen - position + 1);
  328.             continue;
  329.         }
  330.         if (c == '\t') { /* Tabulator */
  331.             int found;
  332.  
  333.             /* Move to the end of the word */
  334.             for (; position < curlen && current[position] != ' ';
  335.                 position++)
  336.                 putchar(current[position]);
  337.             /* Copy to tmp last word */
  338.             for (i = position - 1; i >= 0 && current[i] != ' '; i--)
  339.                 ;
  340.             /* If word begins with * or &, skip it */
  341.             if (tmp[0] == '*' || tmp[0] == '&')
  342.                 for (i = 1; tmp[i]; i++)
  343.                     tmp[i - 1] = tmp[i];
  344.             i++; /* I is at the start of the word */
  345.             strncpy(tmp, current + i, position - i + 1);
  346.  
  347.             if (i == 0) { /* Command completion */
  348.                 found = cmdtab_compl(tmp);
  349.             } else { /* Symtab completion */
  350.                 found = symtab_compl(tmp);
  351.             }
  352.  
  353.             if (found == 0)
  354.                 continue;
  355.             for (i = 0; tmp[i] && curlen < MAX_CMDLINE;
  356.                 i++, curlen++)
  357.                 insert_char(current, tmp[i], i + position);
  358.  
  359.             if (strlen(tmp) || found == 1) { /* If we have a hint */
  360.                 for (i = position; i < curlen; i++)
  361.                     putchar(current[i]);
  362.                 position += strlen(tmp);
  363.                 /* Add space to end */
  364.                 if (found == 1 && position == curlen &&
  365.                     curlen < MAX_CMDLINE) {
  366.                     current[position] = ' ';
  367.                     curlen++;
  368.                     position++;
  369.                     putchar(' ');
  370.                 }
  371.             } else { /* No hint, table was printed */
  372.                 printf("%s> ", prompt);
  373.                 for (i = 0; i < curlen; i++)
  374.                     putchar(current[i]);
  375.                 position += strlen(tmp);
  376.             }
  377.             rdln_print_c('\b', curlen - position);
  378.             continue;
  379.         }
  380.         if (c == 0x1b) { /* Special command */
  381.             mod = _getc(input);
  382.             c = _getc(input);
  383.  
  384.             if (mod != 0x5b && mod != 0x4f)
  385.                 continue;
  386.  
  387.             if (c == 0x33 && _getc(input) == 0x7e) {
  388.                 /* Delete */
  389.                 if (position == curlen)
  390.                     continue;
  391.                 for (i = position + 1; i < curlen; i++) {
  392.                     putchar(current[i]);
  393.                     current[i - 1] = current[i];
  394.                 }
  395.                 putchar(' ');
  396.                 rdln_print_c('\b', curlen - position);
  397.                 curlen--;
  398.             } else if (c == 0x48) { /* Home */
  399.                 rdln_print_c('\b', position);
  400.                 position = 0;
  401.             } else if (c == 0x46) {  /* End */
  402.                 for (i = position; i < curlen; i++)
  403.                     putchar(current[i]);
  404.                 position = curlen;
  405.             } else if (c == 0x44) { /* Left */
  406.                 if (position > 0) {
  407.                     putchar('\b');
  408.                     position--;
  409.                 }
  410.                 continue;
  411.             } else if (c == 0x43) { /* Right */
  412.                 if (position < curlen) {
  413.                     putchar(current[position]);
  414.                     position++;
  415.                 }
  416.                 continue;
  417.             } else if (c == 0x41 || c == 0x42) {
  418.                                 /* Up, down */
  419.                 rdln_print_c('\b', position);
  420.                 rdln_print_c(' ', curlen);
  421.                 rdln_print_c('\b', curlen);
  422.                 if (c == 0x41) /* Up */
  423.                     histposition--;
  424.                 else
  425.                     histposition++;
  426.                 if (histposition < 0) {
  427.                     histposition = KCONSOLE_HISTORY - 1;
  428.                 } else {
  429.                     histposition =
  430.                         histposition % KCONSOLE_HISTORY;
  431.                 }
  432.                 current = history[histposition];
  433.                 printf("%s", current);
  434.                 curlen = strlen(current);
  435.                 position = curlen;
  436.                 continue;
  437.             }
  438.             continue;
  439.         }
  440.         if (curlen >= MAX_CMDLINE)
  441.             continue;
  442.  
  443.         insert_char(current, c, position);
  444.  
  445.         curlen++;
  446.         for (i = position; i < curlen; i++)
  447.             putchar(current[i]);
  448.         position++;
  449.         rdln_print_c('\b',curlen - position);
  450.     }
  451.     if (curlen) {
  452.         histposition++;
  453.         histposition = histposition % KCONSOLE_HISTORY;
  454.     }
  455.     current[curlen] = '\0';
  456.     return current;
  457. }
  458.  
  459. bool kconsole_check_poll(void)
  460. {
  461.     return check_poll(stdin);
  462. }
  463.  
  464. /** Kernel console prompt.
  465.  *
  466.  * @param prompt Kernel console prompt (e.g kconsole/panic).
  467.  * @param msg    Message to display in the beginning.
  468.  * @param kcon   Wait for keypress to show the prompt
  469.  *               and never exit.
  470.  *
  471.  */
  472. void kconsole(char *prompt, char *msg, bool kcon)
  473. {
  474.     cmd_info_t *cmd_info;
  475.     count_t len;
  476.     char *cmdline;
  477.    
  478.     if (!stdin) {
  479.         LOG("No stdin for kernel console");
  480.         return;
  481.     }
  482.    
  483.     if (msg)
  484.         printf("%s", msg);
  485.    
  486.     if (kcon)
  487.         _getc(stdin);
  488.     else
  489.         printf("Type \"exit\" to leave the console.\n");
  490.    
  491.     while (true) {
  492.         cmdline = clever_readline((char *) prompt, stdin);
  493.         len = strlen(cmdline);
  494.         if (!len)
  495.             continue;
  496.        
  497.         if ((!kcon) && (len == 4) && (strncmp(cmdline, "exit", 4) == 0))
  498.             break;
  499.        
  500.         cmd_info = parse_cmdline(cmdline, len);
  501.         if (!cmd_info)
  502.             continue;
  503.        
  504.         (void) cmd_info->func(cmd_info->argv);
  505.     }
  506. }
  507.  
  508. /** Kernel console managing thread.
  509.  *
  510.  */
  511. void kconsole_thread(void *data)
  512. {
  513.     kconsole("kconsole", "Kernel console ready (press any key to activate)\n", true);
  514. }
  515.  
  516. static int parse_int_arg(char *text, size_t len, unative_t *result)
  517. {
  518.     static char symname[MAX_SYMBOL_NAME];
  519.     uintptr_t symaddr;
  520.     bool isaddr = false;
  521.     bool isptr = false;
  522.    
  523.     /* If we get a name, try to find it in symbol table */
  524.     if (text[0] == '&') {
  525.         isaddr = true;
  526.         text++;
  527.         len--;
  528.     } else if (text[0] == '*') {
  529.         isptr = true;
  530.         text++;
  531.         len--;
  532.     }
  533.     if (text[0] < '0' || text[0] > '9') {
  534.         strncpy(symname, text, min(len + 1, MAX_SYMBOL_NAME));
  535.         symaddr = get_symbol_addr(symname);
  536.         if (!symaddr) {
  537.             printf("Symbol %s not found.\n", symname);
  538.             return -1;
  539.         }
  540.         if (symaddr == (uintptr_t) -1) {
  541.             printf("Duplicate symbol %s.\n", symname);
  542.             symtab_print_search(symname);
  543.             return -1;
  544.         }
  545.         if (isaddr)
  546.             *result = (unative_t)symaddr;
  547.         else if (isptr)
  548.             *result = **((unative_t **)symaddr);
  549.         else
  550.             *result = *((unative_t *)symaddr);
  551.     } else { /* It's a number - convert it */
  552.         *result = atoi(text);
  553.         if (isptr)
  554.             *result = *((unative_t *)*result);
  555.     }
  556.  
  557.     return 0;
  558. }
  559.  
  560. /** Parse command line.
  561.  *
  562.  * @param cmdline Command line as read from input device.
  563.  * @param len Command line length.
  564.  *
  565.  * @return Structure describing the command.
  566.  */
  567. cmd_info_t *parse_cmdline(char *cmdline, size_t len)
  568. {
  569.     index_t start = 0, end = 0;
  570.     cmd_info_t *cmd = NULL;
  571.     link_t *cur;
  572.     count_t i;
  573.     int error = 0;
  574.    
  575.     if (!parse_argument(cmdline, len, &start, &end)) {
  576.         /* Command line did not contain alphanumeric word. */
  577.         return NULL;
  578.     }
  579.  
  580.     spinlock_lock(&cmd_lock);
  581.    
  582.     for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {
  583.         cmd_info_t *hlp;
  584.        
  585.         hlp = list_get_instance(cur, cmd_info_t, link);
  586.         spinlock_lock(&hlp->lock);
  587.        
  588.         if (strncmp(hlp->name, &cmdline[start], max(strlen(hlp->name),
  589.             end - start + 1)) == 0) {
  590.             cmd = hlp;
  591.             break;
  592.         }
  593.        
  594.         spinlock_unlock(&hlp->lock);
  595.     }
  596.    
  597.     spinlock_unlock(&cmd_lock);
  598.    
  599.     if (!cmd) {
  600.         /* Unknown command. */
  601.         printf("Unknown command.\n");
  602.         return NULL;
  603.     }
  604.  
  605.     /* cmd == hlp is locked */
  606.    
  607.     /*
  608.      * The command line must be further analyzed and
  609.      * the parameters therefrom must be matched and
  610.      * converted to those specified in the cmd info
  611.      * structure.
  612.      */
  613.  
  614.     for (i = 0; i < cmd->argc; i++) {
  615.         char *buf;
  616.         start = end + 1;
  617.         if (!parse_argument(cmdline, len, &start, &end)) {
  618.             printf("Too few arguments.\n");
  619.             spinlock_unlock(&cmd->lock);
  620.             return NULL;
  621.         }
  622.        
  623.         error = 0;
  624.         switch (cmd->argv[i].type) {
  625.         case ARG_TYPE_STRING:
  626.             buf = (char *) cmd->argv[i].buffer;
  627.             strncpy(buf, (const char *) &cmdline[start],
  628.                 min((end - start) + 2, cmd->argv[i].len));
  629.             buf[min((end - start) + 1, cmd->argv[i].len - 1)] =
  630.                 '\0';
  631.             break;
  632.         case ARG_TYPE_INT:
  633.             if (parse_int_arg(cmdline + start, end - start + 1,
  634.                 &cmd->argv[i].intval))
  635.                 error = 1;
  636.             break;
  637.         case ARG_TYPE_VAR:
  638.             if (start != end && cmdline[start] == '"' &&
  639.                 cmdline[end] == '"') {
  640.                 buf = (char *) cmd->argv[i].buffer;
  641.                 strncpy(buf, (const char *) &cmdline[start + 1],
  642.                     min((end-start), cmd->argv[i].len));
  643.                 buf[min((end - start), cmd->argv[i].len - 1)] =
  644.                     '\0';
  645.                 cmd->argv[i].intval = (unative_t) buf;
  646.                 cmd->argv[i].vartype = ARG_TYPE_STRING;
  647.             } else if (!parse_int_arg(cmdline + start,
  648.                 end - start + 1, &cmd->argv[i].intval)) {
  649.                 cmd->argv[i].vartype = ARG_TYPE_INT;
  650.             } else {
  651.                 printf("Unrecognized variable argument.\n");
  652.                 error = 1;
  653.             }
  654.             break;
  655.         case ARG_TYPE_INVALID:
  656.         default:
  657.             printf("invalid argument type\n");
  658.             error = 1;
  659.             break;
  660.         }
  661.     }
  662.    
  663.     if (error) {
  664.         spinlock_unlock(&cmd->lock);
  665.         return NULL;
  666.     }
  667.    
  668.     start = end + 1;
  669.     if (parse_argument(cmdline, len, &start, &end)) {
  670.         printf("Too many arguments.\n");
  671.         spinlock_unlock(&cmd->lock);
  672.         return NULL;
  673.     }
  674.    
  675.     spinlock_unlock(&cmd->lock);
  676.     return cmd;
  677. }
  678.  
  679. /** Parse argument.
  680.  *
  681.  * Find start and end positions of command line argument.
  682.  *
  683.  * @param cmdline Command line as read from the input device.
  684.  * @param len Number of characters in cmdline.
  685.  * @param start On entry, 'start' contains pointer to the index
  686.  *        of first unprocessed character of cmdline.
  687.  *        On successful exit, it marks beginning of the next argument.
  688.  * @param end Undefined on entry. On exit, 'end' points to the last character
  689.  *        of the next argument.
  690.  *
  691.  * @return false on failure, true on success.
  692.  */
  693. bool parse_argument(char *cmdline, size_t len, index_t *start, index_t *end)
  694. {
  695.     index_t i;
  696.     bool found_start = false;
  697.    
  698.     ASSERT(start != NULL);
  699.     ASSERT(end != NULL);
  700.    
  701.     for (i = *start; i < len; i++) {
  702.         if (!found_start) {
  703.             if (isspace(cmdline[i]))
  704.                 (*start)++;
  705.             else
  706.                 found_start = true;
  707.         } else {
  708.             if (isspace(cmdline[i]))
  709.                 break;
  710.         }
  711.     }
  712.     *end = i - 1;
  713.  
  714.     return found_start;
  715. }
  716.  
  717. /** @}
  718.  */
  719.