dos/argv.c

   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 }