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      1 /* ----------------------------------------------------------------------- *
      2  *
      3  *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
      4  *   Copyright 2013 Intel Corporation; author: H. Peter Anvin
      5  *
      6  *   Permission is hereby granted, free of charge, to any person
      7  *   obtaining a copy of this software and associated documentation
      8  *   files (the "Software"), to deal in the Software without
      9  *   restriction, including without limitation the rights to use,
     10  *   copy, modify, merge, publish, distribute, sublicense, and/or
     11  *   sell copies of the Software, and to permit persons to whom
     12  *   the Software is furnished to do so, subject to the following
     13  *   conditions:
     14  *
     15  *   The above copyright notice and this permission notice shall
     16  *   be included in all copies or substantial portions of the Software.
     17  *
     18  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     19  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
     20  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     21  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
     22  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     23  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     24  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     25  *   OTHER DEALINGS IN THE SOFTWARE.
     26  *
     27  * ----------------------------------------------------------------------- */
     28 
     29 /*
     30  * argv.c
     31  *
     32  * Parse the MS-DOS command line into argc and argv (argc is return value.)
     33  * memptr points to available memory.
     34  */
     35 
     36 #include <inttypes.h>
     37 #include <stddef.h>
     38 #include <stdbool.h>
     39 #include "mystuff.h"
     40 
     41 #define ALIGN_UP(p,t)       ((t *)(((uintptr_t)(p) + (sizeof(t)-1)) & ~(sizeof(t)-1)))
     42 
     43 extern char __heap_start[];
     44 void *__mem_end = &__heap_start;	/* Global variable for use by malloc() */
     45 
     46 int __parse_argv(char ***argv)
     47 {
     48     char *mem = __mem_end;
     49     const char *str, *p;
     50     char *q = mem;
     51     char c, *r;
     52     char **arg;
     53     bool wasspace;
     54     int argc;
     55     int len;
     56     size_t offs;
     57     int nulls;
     58     uint16_t nstr;
     59 
     60     /* Find and copy argv[0] after the environment block */
     61     set_fs(_PSP.environment);
     62     offs = 0;
     63     nulls = 0;
     64     do {
     65 	if (get_8_fs(offs++) == '\0')
     66 	    nulls++;
     67 	else
     68 	    nulls = 0;
     69     } while (nulls < 2);
     70 
     71     nstr = get_16_fs(offs);
     72     offs += 2;
     73 
     74     /* Copy the null-terminated filename string */
     75     if (nstr >= 1) {
     76 	while ((c = get_8_fs(offs++)))
     77 	    *q++ = c;
     78     }
     79     *q++ = '\0';
     80 
     81     /* Now for the command line tail... */
     82 
     83     len = _PSP.cmdlen;
     84     str = _PSP.cmdtail;
     85     argc = 1;
     86     wasspace = true;
     87 
     88     /* Copy the command tail, turning whitespace runs into nulls */
     89     for (p = str;; p++) {
     90 	if (!len || *p <= ' ') {
     91 	    if (!wasspace) {
     92 		wasspace = true;
     93 		*q++ = '\0';
     94 	    }
     95 	} else {
     96 	    if (wasspace) {
     97 		argc++;
     98 		wasspace = false;
     99 	    }
    100 	    *q++ = *p;
    101 	}
    102 
    103 	/* This test is AFTER we have processed the end byte;
    104 	   we treat it as a whitespace character so it terminates
    105 	   the last argument */
    106 	if (!len--)
    107 	    break;
    108     }
    109 
    110     /* Now create argv */
    111     arg = ALIGN_UP(q, char *);
    112     *argv = arg;
    113     *arg++ = mem;		/* argv[0] */
    114 
    115     q--;			/* Point q to terminal character */
    116     for (r = mem; r < q; r++) {
    117 	if (*r == '\0') {
    118 	    *arg++ = r + 1;
    119 	}
    120     }
    121 
    122     *arg++ = NULL;		/* Null pointer at the end */
    123     __mem_end = arg;		/* End of memory we used */
    124 
    125     return argc;
    126 }
    127