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
17 #include <sys/cdefs.h>
18 __FBSDID("$FreeBSD$");
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
66 if (ch == '{')
67 return '}';
68 else if (ch == '(')
69 return ')';
70 return '\0';
71 }
72
73 static int
isquote(int ch)74 isquote(int ch)
75 {
76
77 return (ch == '\'');
78 }
79
80 static int
isdquote(int ch)81 isdquote(int ch)
82 {
83
84 return (ch == '"');
85 }
86
87 int
parse(int * argc,char *** argv,const char * str)88 parse(int *argc, char ***argv, const char *str)
89 {
90 int ac;
91 char *val, *p, *q, *copy = NULL;
92 size_t i = 0;
93 char token, tmp, quote, dquote, *buf;
94 enum { STR, VAR, WHITE } state;
95
96 ac = *argc = 0;
97 dquote = quote = 0;
98 if (!str || (p = copy = backslash(str)) == NULL)
99 return 1;
100
101 /* Initialize vector and state */
102 clean();
103 state = STR;
104 buf = (char *)malloc(PARSE_BUFSIZE);
105 token = 0;
106
107 /* And awaaaaaaaaay we go! */
108 while (*p) {
109 switch (state) {
110 case STR:
111 if ((*p == '\\') && p[1]) {
112 p++;
113 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
114 buf[i++] = *p++;
115 } else if (isquote(*p)) {
116 quote = quote ? 0 : *p;
117 if (dquote) { /* keep quote */
118 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
119 buf[i++] = *p++;
120 } else
121 ++p;
122 } else if (isdquote(*p)) {
123 dquote = dquote ? 0 : *p;
124 if (quote) { /* keep dquote */
125 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
126 buf[i++] = *p++;
127 } else
128 ++p;
129 } else if (isspace(*p) && !quote && !dquote) {
130 state = WHITE;
131 if (i) {
132 buf[i] = '\0';
133 PARSE_FAIL(insert(&ac, buf));
134 i = 0;
135 }
136 ++p;
137 } else if (*p == '$' && !quote) {
138 token = isdelim(*(p + 1));
139 if (token)
140 p += 2;
141 else
142 ++p;
143 state = VAR;
144 } else {
145 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
146 buf[i++] = *p++;
147 }
148 break;
149
150 case WHITE:
151 if (isspace(*p))
152 ++p;
153 else
154 state = STR;
155 break;
156
157 case VAR:
158 if (token) {
159 PARSE_FAIL((q = strchr(p, token)) == NULL);
160 } else {
161 q = p;
162 while (*q && !isspace(*q))
163 ++q;
164 }
165 tmp = *q;
166 *q = '\0';
167 if ((val = variable_lookup(p)) != NULL) {
168 size_t len = strlen(val);
169
170 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1));
171 i += min(len, PARSE_BUFSIZE - 1);
172 }
173 *q = tmp; /* restore value */
174 p = q + (token ? 1 : 0);
175 state = STR;
176 break;
177 }
178 }
179 /* missing terminating ' or " */
180 PARSE_FAIL(quote || dquote);
181 /* If at end of token, add it */
182 if (i && state == STR) {
183 buf[i] = '\0';
184 PARSE_FAIL(insert(&ac, buf));
185 }
186 args[ac] = NULL;
187 *argc = ac;
188 *argv = (char **)malloc((sizeof(char *) * ac + 1));
189 bcopy(args, *argv, sizeof(char *) * ac + 1);
190 free(buf);
191 free(copy);
192 return 0;
193 }
194
195 #define MAXARGS 20
196
197 /* Clean vector space */
198 static void
clean(void)199 clean(void)
200 {
201 int i;
202
203 for (i = 0; i < MAXARGS; i++) {
204 if (args[i] != NULL) {
205 free(args[i]);
206 args[i] = NULL;
207 }
208 }
209 }
210
211 static int
insert(int * argcp,char * buf)212 insert(int *argcp, char *buf)
213 {
214
215 if (*argcp >= MAXARGS)
216 return 1;
217 args[(*argcp)++] = strdup(buf);
218 return 0;
219 }
220
221 static char *
variable_lookup(char * name)222 variable_lookup(char *name)
223 {
224
225 /* XXX search "special variable" space first? */
226 return (char *)getenv(name);
227 }
228