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 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 74 isquote(int ch) 75 { 76 77 return (ch == '\''); 78 } 79 80 static int 81 isdquote(int ch) 82 { 83 84 return (ch == '"'); 85 } 86 87 int 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 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 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 * 222 variable_lookup(char *name) 223 { 224 225 /* XXX search "special variable" space first? */ 226 return (char *)getenv(name); 227 } 228