1 /* $NetBSD: interp_parse.c,v 1.6 2018/09/04 15:08:30 riastradh Exp $ */
2
3 /*-
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * Jordan K. Hubbard
14 * 29 August 1998
15 *
16 * The meat of the simple parser.
17 */
18
19 #include <sys/cdefs.h>
20 /* __FBSDID("$FreeBSD: src/sys/boot/common/interp_parse.c,v 1.10 2003/08/25 23:30:41 obrien Exp $"); */
21
22 #include <lib/libsa/stand.h>
23 #include <lib/libsa/loadfile.h>
24 #include <lib/libkern/libkern.h>
25
26 #include "bootstrap.h"
27
28 static void clean(void);
29 static int insert(int *argcp, char *buf);
30 static char *variable_lookup(char *name);
31
32 #define PARSE_BUFSIZE 1024 /* maximum size of one element */
33 #define MAXARGS 20 /* maximum number of elements */
34 static char *args[MAXARGS];
35
36 /*
37 * parse: accept a string of input and "parse" it for backslash
38 * substitutions and environment variable expansions (${var}),
39 * returning an argc/argv style vector of whitespace separated
40 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I
41 * wimped-out on the error codes! :).
42 *
43 * Note that the argv array returned must be freed by the caller, but
44 * we own the space allocated for arguments and will free that on next
45 * invocation. This allows argv consumers to modify the array if
46 * required.
47 *
48 * NB: environment variables that expand to more than one whitespace
49 * separated token will be returned as a single argv[] element, not
50 * split in turn. Expanded text is also immune to further backslash
51 * elimination or expansion since this is a one-pass, non-recursive
52 * parser. You didn't specify more than this so if you want more, ask
53 * me. - jkh
54 */
55
56 #define PARSE_FAIL(expr) \
57 if (expr) { \
58 printf("fail at line %d\n", __LINE__); \
59 clean(); \
60 free(copy); \
61 free(buf); \
62 return 1; \
63 }
64
65 /* Accept the usual delimiters for a variable, returning counterpart */
66 static char
isdelim(int ch)67 isdelim(int ch)
68 {
69 if (ch == '{')
70 return '}';
71 else if (ch == '(')
72 return ')';
73 return '\0';
74 }
75
76 static int
isquote(int ch)77 isquote(int ch)
78 {
79 return (ch == '\'' || ch == '"');
80 }
81
82 int
parse(int * argc,char *** argv,char * str)83 parse(int *argc, char ***argv, char *str)
84 {
85 int ac;
86 char *val, *p, *q, *copy = NULL;
87 size_t i = 0;
88 char token, tmp, quote, *buf;
89 enum { STR, VAR, WHITE } state;
90
91 ac = *argc = 0;
92 quote = 0;
93 if (!str || (p = copy = backslash(str)) == NULL)
94 return 1;
95
96 /* Initialize vector and state */
97 clean();
98 state = STR;
99 buf = (char *)alloc(PARSE_BUFSIZE);
100 token = 0;
101
102 /* And awaaaaaaaaay we go! */
103 while (*p) {
104 switch (state) {
105 case STR:
106 if ((*p == '\\') && p[1]) {
107 p++;
108 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
109 buf[i++] = *p++;
110 } else if (isquote(*p)) {
111 quote = quote ? 0 : *p;
112 ++p;
113 }
114 else if (isspace(*p) && !quote) {
115 state = WHITE;
116 if (i) {
117 buf[i] = '\0';
118 PARSE_FAIL(insert(&ac, buf));
119 i = 0;
120 }
121 ++p;
122 } else if (*p == '$') {
123 token = isdelim(*(p + 1));
124 if (token)
125 p += 2;
126 else
127 ++p;
128 state = VAR;
129 } else {
130 PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
131 buf[i++] = *p++;
132 }
133 break;
134
135 case WHITE:
136 if (isspace(*p))
137 ++p;
138 else
139 state = STR;
140 break;
141
142 case VAR:
143 if (token) {
144 PARSE_FAIL((q = strchr(p, token)) == NULL);
145 } else {
146 q = p;
147 while (*q && !isspace(*q))
148 ++q;
149 }
150 tmp = *q;
151 *q = '\0';
152 if ((val = variable_lookup(p)) != NULL) {
153 size_t len = strlen(val);
154
155 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1));
156 i += uimin(len, PARSE_BUFSIZE - 1);
157 }
158 *q = tmp; /* restore value */
159 p = q + (token ? 1 : 0);
160 state = STR;
161 break;
162 }
163 }
164 /* If at end of token, add it */
165 if (i && state == STR) {
166 buf[i] = '\0';
167 PARSE_FAIL(insert(&ac, buf));
168 }
169 args[ac] = NULL;
170 *argc = ac;
171 *argv = (char **)alloc((sizeof(char *) * ac + 1));
172 memcpy(*argv, args, sizeof(char *) * ac + 1);
173 free(buf);
174 free(copy);
175 return 0;
176 }
177
178 #define MAXARGS 20
179
180 /* Clean vector space */
181 static void
clean(void)182 clean(void)
183 {
184 int i;
185
186 for (i = 0; i < MAXARGS; i++) {
187 if (args[i] != NULL) {
188 free(args[i]);
189 args[i] = NULL;
190 }
191 }
192 }
193
194 static int
insert(int * argcp,char * buf)195 insert(int *argcp, char *buf)
196 {
197 if (*argcp >= MAXARGS)
198 return 1;
199 args[(*argcp)++] = strdup(buf);
200 return 0;
201 }
202
203 static char *
variable_lookup(char * name)204 variable_lookup(char *name)
205 {
206 /* XXX search "special variable" space first? */
207 return (char *)getenv(name);
208 }
209