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
43extern char __heap_start[];
44void *__mem_end = &__heap_start;	/* Global variable for use by malloc() */
45
46int __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