1/*
2 * argv_parse.c --- utility function for parsing a string into a
3 * 	argc, argv array.
4 *
5 * This file defines a function argv_parse() which parsing a
6 * passed-in string, handling double quotes and backslashes, and
7 * creates an allocated argv vector which can be freed using the
8 * argv_free() function.
9 *
10 * See argv_parse.h for the formal definition of the functions.
11 *
12 * Copyright 1999 by Theodore Ts'o.
13 *
14 * Permission to use, copy, modify, and distribute this software for
15 * any purpose with or without fee is hereby granted, provided that
16 * the above copyright notice and this permission notice appear in all
17 * copies.  THE SOFTWARE IS PROVIDED "AS IS" AND THEODORE TS'O (THE
18 * AUTHOR) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
21 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
22 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
23 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
24 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  (Isn't
25 * it sick that the U.S. culture of lawsuit-happy lawyers requires
26 * this kind of disclaimer?)
27 *
28 * Version 1.1, modified 2/27/1999
29 */
30
31#ifdef HAVE_STDLIB_H
32#include <stdlib.h>
33#endif
34#include <ctype.h>
35#include <string.h>
36#include "argv_parse.h"
37
38#define STATE_WHITESPACE	1
39#define STATE_TOKEN		2
40#define STATE_QUOTED		3
41
42/*
43 * Returns 0 on success, -1 on failure.
44 */
45int argv_parse(char *in_buf, int *ret_argc, char ***ret_argv)
46{
47	int	argc = 0, max_argc = 0;
48	char 	**argv, **new_argv, *buf, ch;
49	char	*cp = 0, *outcp = 0;
50	int	state = STATE_WHITESPACE;
51
52	buf = malloc(strlen(in_buf)+1);
53	if (!buf)
54		return -1;
55
56	max_argc = 0; argc = 0; argv = 0;
57	outcp = buf;
58	for (cp = in_buf; (ch = *cp); cp++) {
59		if (state == STATE_WHITESPACE) {
60			if (isspace((int) ch))
61				continue;
62			/* Not whitespace, so start a new token */
63			state = STATE_TOKEN;
64			if (argc >= max_argc) {
65				max_argc += 3;
66				new_argv = realloc(argv,
67						  (max_argc+1)*sizeof(char *));
68				if (!new_argv) {
69					free(argv);
70					free(buf);
71					return -1;
72				}
73				argv = new_argv;
74			}
75			argv[argc++] = outcp;
76		}
77		if (state == STATE_QUOTED) {
78			if (ch == '"')
79				state = STATE_TOKEN;
80			else
81				*outcp++ = ch;
82			continue;
83		}
84		/* Must be processing characters in a word */
85		if (isspace((int) ch)) {
86			/*
87			 * Terminate the current word and start
88			 * looking for the beginning of the next word.
89			 */
90			*outcp++ = 0;
91			state = STATE_WHITESPACE;
92			continue;
93		}
94		if (ch == '"') {
95			state = STATE_QUOTED;
96			continue;
97		}
98		if (ch == '\\') {
99			ch = *++cp;
100			switch (ch) {
101			case '\0':
102				ch = '\\'; cp--; break;
103			case 'n':
104				ch = '\n'; break;
105			case 't':
106				ch = '\t'; break;
107			case 'b':
108				ch = '\b'; break;
109			}
110		}
111		*outcp++ = ch;
112	}
113	if (state != STATE_WHITESPACE)
114		*outcp++ = '\0';
115	if (argv == 0) {
116		argv = malloc(sizeof(char *));
117		free(buf);
118	}
119	argv[argc] = 0;
120	if (ret_argc)
121		*ret_argc = argc;
122	if (ret_argv)
123		*ret_argv = argv;
124	return 0;
125}
126
127void argv_free(char **argv)
128{
129	free(*argv);
130	free(argv);
131}
132
133#ifdef DEBUG
134/*
135 * For debugging
136 */
137
138#include <stdio.h>
139
140int main(int argc, char **argv)
141{
142	int	ac, ret;
143	char	**av, **cpp;
144	char	buf[256];
145
146	while (!feof(stdin)) {
147		if (fgets(buf, sizeof(buf), stdin) == NULL)
148			break;
149		ret = argv_parse(buf, &ac, &av);
150		if (ret != 0) {
151			printf("Argv_parse returned %d!\n", ret);
152			continue;
153		}
154		printf("Argv_parse returned %d arguments...\n", ac);
155		for (cpp = av; *cpp; cpp++) {
156			if (cpp != av)
157				printf(", ");
158			printf("'%s'", *cpp);
159		}
160		printf("\n");
161		argv_free(av);
162	}
163	exit(0);
164}
165#endif /* DEBUG */
166