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