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 19 #include <stand.h> 20 #include <string.h> 21 #include "bootstrap.h" 22 23 static void clean(void); 24 static int insert(int *argcp, char *buf); 25 static char *variable_lookup(char *name); 26 27 #define PARSE_BUFSIZE 1024 /* maximum size of one element */ 28 #define MAXARGS 20 /* maximum number of elements */ 29 static char *args[MAXARGS]; 30 31 /* 32 * parse: accept a string of input and "parse" it for backslash 33 * substitutions and environment variable expansions (${var}), 34 * returning an argc/argv style vector of whitespace separated 35 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I 36 * wimped-out on the error codes! :). 37 * 38 * Note that the argv array returned must be freed by the caller, but 39 * we own the space allocated for arguments and will free that on next 40 * invocation. This allows argv consumers to modify the array if 41 * required. 42 * 43 * NB: environment variables that expand to more than one whitespace 44 * separated token will be returned as a single argv[] element, not 45 * split in turn. Expanded text is also immune to further backslash 46 * elimination or expansion since this is a one-pass, non-recursive 47 * parser. You didn't specify more than this so if you want more, ask 48 * me. - jkh 49 */ 50 51 #define PARSE_FAIL(expr) \ 52 if (expr) { \ 53 printf("fail at line %d\n", __LINE__); \ 54 clean(); \ 55 free(copy); \ 56 free(buf); \ 57 return (1); \ 58 } 59 60 /* Accept the usual delimiters for a variable, returning counterpart */ 61 static char 62 isdelim(int ch) 63 { 64 if (ch == '{') 65 return ('}'); 66 else if (ch == '(') 67 return (')'); 68 return ('\0'); 69 } 70 71 static int 72 isquote(int ch) 73 { 74 return (ch == '\''); 75 } 76 77 static int 78 isdquote(int ch) 79 { 80 return (ch == '"'); 81 } 82 83 int 84 parse(int *argc, char ***argv, char *str) 85 { 86 int ac; 87 char *val, *p, *q, *copy = NULL; 88 size_t i = 0; 89 char token, tmp, quote, dquote, *buf; 90 enum { STR, VAR, WHITE } state; 91 92 ac = *argc = 0; 93 dquote = quote = 0; 94 if (!str || (p = copy = backslash(str)) == NULL) 95 return (1); 96 97 /* Initialize vector and state */ 98 clean(); 99 state = STR; 100 buf = malloc(PARSE_BUFSIZE); 101 token = 0; 102 103 /* And awaaaaaaaaay we go! */ 104 while (*p) { 105 switch (state) { 106 case STR: 107 if ((*p == '\\') && p[1]) { 108 p++; 109 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 110 buf[i++] = *p++; 111 } else if (isquote(*p)) { 112 quote = quote ? 0 : *p; 113 if (dquote) { /* keep quote */ 114 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 115 buf[i++] = *p++; 116 } else { 117 ++p; 118 } 119 } else if (isdquote(*p)) { 120 dquote = dquote ? 0 : *p; 121 if (quote) { /* keep dquote */ 122 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 123 buf[i++] = *p++; 124 } else { 125 ++p; 126 } 127 } else if (isspace(*p) && !quote && !dquote) { 128 state = WHITE; 129 if (i) { 130 buf[i] = '\0'; 131 PARSE_FAIL(insert(&ac, buf)); 132 i = 0; 133 } 134 ++p; 135 } else if (*p == '$' && !quote) { 136 token = isdelim(*(p + 1)); 137 if (token) 138 p += 2; 139 else 140 ++p; 141 state = VAR; 142 } else { 143 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 144 buf[i++] = *p++; 145 } 146 break; 147 148 case WHITE: 149 if (isspace(*p)) 150 ++p; 151 else 152 state = STR; 153 break; 154 155 case VAR: 156 if (token) { 157 PARSE_FAIL((q = strchr(p, token)) == NULL); 158 } else { 159 q = p; 160 while (*q && !isspace(*q)) 161 ++q; 162 } 163 tmp = *q; 164 *q = '\0'; 165 if ((val = variable_lookup(p)) != NULL) { 166 size_t len = strlen(val); 167 168 (void) strncpy(buf + i, val, 169 PARSE_BUFSIZE - (i + 1)); 170 i += min(len, PARSE_BUFSIZE - 1); 171 } 172 *q = tmp; /* restore value */ 173 p = q + (token ? 1 : 0); 174 state = STR; 175 break; 176 } 177 } 178 /* missing terminating ' or " */ 179 PARSE_FAIL(quote || dquote); 180 /* If at end of token, add it */ 181 if (i && state == STR) { 182 buf[i] = '\0'; 183 PARSE_FAIL(insert(&ac, buf)); 184 } 185 args[ac] = NULL; 186 *argc = ac; 187 *argv = malloc((sizeof (char *) * ac + 1)); 188 bcopy(args, *argv, sizeof (char *) * ac + 1); 189 free(buf); 190 free(copy); 191 return (0); 192 } 193 194 #define MAXARGS 20 195 196 /* Clean vector space */ 197 static void 198 clean(void) 199 { 200 int i; 201 202 for (i = 0; i < MAXARGS; i++) { 203 free(args[i]); 204 args[i] = NULL; 205 } 206 } 207 208 static int 209 insert(int *argcp, char *buf) 210 { 211 if (*argcp >= MAXARGS) 212 return (1); 213 args[(*argcp)++] = strdup(buf); 214 return (0); 215 } 216 217 static char * 218 variable_lookup(char *name) 219 { 220 221 /* XXX search "special variable" space first? */ 222 return (getenv(name)); 223 } 224