1 /* $NetBSD: interp_parse.c,v 1.2 2006/04/22 07:58:53 cherry 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 $"); */ 21 22 #include <lib/libsa/stand.h> 23 #include <lib/libkern/libkern.h> 24 25 #include "bootstrap.h" 26 27 static void clean(void); 28 static int insert(int *argcp, char *buf); 29 static char *variable_lookup(char *name); 30 31 #define PARSE_BUFSIZE 1024 /* maximum size of one element */ 32 #define MAXARGS 20 /* maximum number of elements */ 33 static char *args[MAXARGS]; 34 35 /* 36 * parse: accept a string of input and "parse" it for backslash 37 * substitutions and environment variable expansions (${var}), 38 * returning an argc/argv style vector of whitespace separated 39 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I 40 * wimped-out on the error codes! :). 41 * 42 * Note that the argv array returned must be freed by the caller, but 43 * we own the space allocated for arguments and will free that on next 44 * invocation. This allows argv consumers to modify the array if 45 * required. 46 * 47 * NB: environment variables that expand to more than one whitespace 48 * separated token will be returned as a single argv[] element, not 49 * split in turn. Expanded text is also immune to further backslash 50 * elimination or expansion since this is a one-pass, non-recursive 51 * parser. You didn't specify more than this so if you want more, ask 52 * me. - jkh 53 */ 54 55 #define PARSE_FAIL(expr) \ 56 if (expr) { \ 57 printf("fail at line %d\n", __LINE__); \ 58 clean(); \ 59 free(copy); \ 60 free(buf); \ 61 return 1; \ 62 } 63 64 /* Accept the usual delimiters for a variable, returning counterpart */ 65 static char 66 isdelim(int ch) 67 { 68 if (ch == '{') 69 return '}'; 70 else if (ch == '(') 71 return ')'; 72 return '\0'; 73 } 74 75 static int 76 isquote(int ch) 77 { 78 return (ch == '\'' || ch == '"'); 79 } 80 81 int 82 parse(int *argc, char ***argv, char *str) 83 { 84 int ac; 85 char *val, *p, *q, *copy = NULL; 86 size_t i = 0; 87 char token, tmp, quote, *buf; 88 enum { STR, VAR, WHITE } state; 89 90 ac = *argc = 0; 91 quote = 0; 92 if (!str || (p = copy = backslash(str)) == NULL) 93 return 1; 94 95 /* Initialize vector and state */ 96 clean(); 97 state = STR; 98 buf = (char *)alloc(PARSE_BUFSIZE); 99 token = 0; 100 101 /* And awaaaaaaaaay we go! */ 102 while (*p) { 103 switch (state) { 104 case STR: 105 if ((*p == '\\') && p[1]) { 106 p++; 107 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 108 buf[i++] = *p++; 109 } else if (isquote(*p)) { 110 quote = quote ? 0 : *p; 111 ++p; 112 } 113 else if (isspace(*p) && !quote) { 114 state = WHITE; 115 if (i) { 116 buf[i] = '\0'; 117 PARSE_FAIL(insert(&ac, buf)); 118 i = 0; 119 } 120 ++p; 121 } else if (*p == '$') { 122 token = isdelim(*(p + 1)); 123 if (token) 124 p += 2; 125 else 126 ++p; 127 state = VAR; 128 } else { 129 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 130 buf[i++] = *p++; 131 } 132 break; 133 134 case WHITE: 135 if (isspace(*p)) 136 ++p; 137 else 138 state = STR; 139 break; 140 141 case VAR: 142 if (token) { 143 PARSE_FAIL((q = strchr(p, token)) == NULL); 144 } else { 145 q = p; 146 while (*q && !isspace(*q)) 147 ++q; 148 } 149 tmp = *q; 150 *q = '\0'; 151 if ((val = variable_lookup(p)) != NULL) { 152 size_t len = strlen(val); 153 154 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1)); 155 i += min(len, PARSE_BUFSIZE - 1); 156 } 157 *q = tmp; /* restore value */ 158 p = q + (token ? 1 : 0); 159 state = STR; 160 break; 161 } 162 } 163 /* If at end of token, add it */ 164 if (i && state == STR) { 165 buf[i] = '\0'; 166 PARSE_FAIL(insert(&ac, buf)); 167 } 168 args[ac] = NULL; 169 *argc = ac; 170 *argv = (char **)alloc((sizeof(char *) * ac + 1)); 171 bcopy(args, *argv, sizeof(char *) * ac + 1); 172 free(buf); 173 free(copy); 174 return 0; 175 } 176 177 #define MAXARGS 20 178 179 /* Clean vector space */ 180 static void 181 clean(void) 182 { 183 int i; 184 185 for (i = 0; i < MAXARGS; i++) { 186 if (args[i] != NULL) { 187 free(args[i]); 188 args[i] = NULL; 189 } 190 } 191 } 192 193 static int 194 insert(int *argcp, char *buf) 195 { 196 if (*argcp >= MAXARGS) 197 return 1; 198 args[(*argcp)++] = strdup(buf); 199 return 0; 200 } 201 202 static char * 203 variable_lookup(char *name) 204 { 205 /* XXX search "special variable" space first? */ 206 return (char *)getenv(name); 207 } 208