1 /*-
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that the following conditions
4 * are met:
5 * 1. Redistributions of source code must retain the above copyright
6 * notice, this list of conditions and the following disclaimer.
7 * 2. Redistributions in binary form must reproduce the above copyright
8 * notice, this list of conditions and the following disclaimer in the
9 * documentation and/or other materials provided with the distribution.
10 *
11 * Jordan K. Hubbard
12 * 29 August 1998
13 *
14 * The meat of the simple parser.
15 *
16 * $FreeBSD: src/sys/boot/common/interp_parse.c,v 1.10 2003/08/25 23:30:41 obrien Exp $
17 * $DragonFly: src/sys/boot/common/interp_parse.c,v 1.3 2003/11/10 06:08:31 dillon Exp $
18 */
19
20 #include <stand.h>
21 #include <string.h>
22 #include "bootstrap.h"
23
24 static void clean(void);
25 static int insert(int *argcp, char *buf);
26 static char *variable_lookup(char *name);
27
28 #define PARSE_BUFSIZE 1024 /* maximum size of one element */
29 #define MAXARGS 20 /* maximum number of elements */
30 static char *args[MAXARGS];
31
32 /*
33 * parse: accept a string of input and "parse" it for backslash
34 * substitutions and environment variable expansions (${var}),
35 * returning an argc/argv style vector of whitespace separated
36 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I
37 * wimped-out on the error codes! :).
38 *
39 * Note that the argv array returned must be freed by the caller, but
40 * we own the space allocated for arguments and will free that on next
41 * invocation. This allows argv consumers to modify the array if
42 * required.
43 *
44 * NB: environment variables that expand to more than one whitespace
45 * separated token will be returned as a single argv[] element, not
46 * split in turn. Expanded text is also immune to further backslash
47 * elimination or expansion since this is a one-pass, non-recursive
48 * parser. You didn't specify more than this so if you want more, ask
49 * me. - jkh
50 */
51
52 #define PARSE_FAIL(expr) \
53 if (expr) { \
54 printf("fail at line %d\n", __LINE__); \
55 clean(); \
56 free(copy); \
57 free(buf); \
58 return 1; \
59 }
60
61 /* Accept the usual delimiters for a variable, returning counterpart */
62 static char
isdelim(int ch)63 isdelim(int ch)
64 {
65 if (ch == '{')
66 return '}';
67 else if (ch == '(')
68 return ')';
69 return '\0';
70 }
71
72 static int
isquote(int ch)73 isquote(int ch)
74 {
75 return (ch == '\'' || ch == '"');
76 }
77
78 int
parse(int * argc,char *** argv,char * str)79 parse(int *argc, char ***argv, char *str)
80 {
81 int ac;
82 char *val, *p, *q, *copy = NULL;
83 size_t i = 0;
84 char token, tmp, quote, *buf;
85 enum { STR, VAR, WHITE } state;
86
87 ac = *argc = 0;
88 quote = 0;
89 if (!str || (p = copy = backslash(str)) == NULL)
90 return 1;
91
92 /* Initialize vector and state */
93 clean();
94 state = STR;
95 buf = (char *)malloc(PARSE_BUFSIZE);
96 token = 0;
97
98 /* And awaaaaaaaaay we go! */
99 while (*p) {
100 switch (state) {
101 case STR:
102 /*
103 * Check comment
104 */
105 if (*p == '#' && quote == 0) {
106 *p = 0;
107 break;
108 }
109
110 /*
111 * Check line continuation
112 */
113 if (*p == '\\' && p[1]) {
114 p++;
115 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
116 buf[i++] = *p++;
117 } else if (isquote(*p)) {
118 quote = quote ? 0 : *p;
119 ++p;
120 }
121 else if (isspace(*p) && !quote) {
122 state = WHITE;
123 if (i) {
124 buf[i] = '\0';
125 PARSE_FAIL(insert(&ac, buf));
126 i = 0;
127 }
128 ++p;
129 } else if (*p == '$') {
130 token = isdelim(*(p + 1));
131 if (token)
132 p += 2;
133 else
134 ++p;
135 state = VAR;
136 } else {
137 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
138 buf[i++] = *p++;
139 }
140 break;
141
142 case WHITE:
143 if (isspace(*p))
144 ++p;
145 else
146 state = STR;
147 break;
148
149 case VAR:
150 if (token) {
151 PARSE_FAIL((q = index(p, token)) == NULL);
152 } else {
153 q = p;
154 while (*q && !isspace(*q))
155 ++q;
156 }
157 tmp = *q;
158 *q = '\0';
159 if ((val = variable_lookup(p)) != NULL) {
160 size_t len = strlen(val);
161
162 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1));
163 i += min(len, PARSE_BUFSIZE - 1);
164 }
165 *q = tmp; /* restore value */
166 p = q + (token ? 1 : 0);
167 state = STR;
168 break;
169 }
170 }
171 /* If at end of token, add it */
172 if (i && state == STR) {
173 buf[i] = '\0';
174 PARSE_FAIL(insert(&ac, buf));
175 }
176 args[ac] = NULL;
177 *argc = ac;
178 *argv = (char **)malloc(sizeof(char *) * (ac + 1));
179 bcopy(args, *argv, sizeof(char *) * (ac + 1));
180 free(buf);
181 free(copy);
182 return 0;
183 }
184
185 #define MAXARGS 20
186
187 /* Clean vector space */
188 static void
clean(void)189 clean(void)
190 {
191 int i;
192
193 for (i = 0; i < MAXARGS; i++) {
194 if (args[i] != NULL) {
195 free(args[i]);
196 args[i] = NULL;
197 }
198 }
199 }
200
201 static int
insert(int * argcp,char * buf)202 insert(int *argcp, char *buf)
203 {
204 if (*argcp >= MAXARGS)
205 return 1;
206 args[(*argcp)++] = strdup(buf);
207 return 0;
208 }
209
210 static char *
variable_lookup(char * name)211 variable_lookup(char *name)
212 {
213 /* XXX search "special variable" space first? */
214 return (char *)getenv(name);
215 }
216