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 <stand.h> 18 #include <string.h> 19 #include "bootstrap.h" 20 21 static void clean(void); 22 static int insert(int *argcp, char *buf); 23 static char *variable_lookup(char *name); 24 25 #define PARSE_BUFSIZE 1024 /* maximum size of one element */ 26 #define MAXARGS 20 /* maximum number of elements */ 27 static char *args[MAXARGS]; 28 29 /* 30 * parse: accept a string of input and "parse" it for backslash 31 * substitutions and environment variable expansions (${var}), 32 * returning an argc/argv style vector of whitespace separated 33 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I 34 * wimped-out on the error codes! :). 35 * 36 * Note that the argv array returned must be freed by the caller, but 37 * we own the space allocated for arguments and will free that on next 38 * invocation. This allows argv consumers to modify the array if 39 * required. 40 * 41 * NB: environment variables that expand to more than one whitespace 42 * separated token will be returned as a single argv[] element, not 43 * split in turn. Expanded text is also immune to further backslash 44 * elimination or expansion since this is a one-pass, non-recursive 45 * parser. You didn't specify more than this so if you want more, ask 46 * me. - jkh 47 */ 48 49 #define PARSE_FAIL(expr) \ 50 if (expr) { \ 51 printf("fail at line %d\n", __LINE__); \ 52 clean(); \ 53 free(copy); \ 54 free(buf); \ 55 return 1; \ 56 } 57 58 /* Accept the usual delimiters for a variable, returning counterpart */ 59 static char 60 isdelim(int ch) 61 { 62 63 if (ch == '{') 64 return '}'; 65 else if (ch == '(') 66 return ')'; 67 return '\0'; 68 } 69 70 static int 71 isquote(int ch) 72 { 73 74 return (ch == '\''); 75 } 76 77 static int 78 isdquote(int ch) 79 { 80 81 return (ch == '"'); 82 } 83 84 int 85 parse(int *argc, char ***argv, const char *str) 86 { 87 int ac; 88 char *val, *p, *q, *copy = NULL; 89 size_t i = 0; 90 char token, tmp, quote, dquote, *buf; 91 enum { STR, VAR, WHITE } state; 92 93 ac = *argc = 0; 94 dquote = quote = 0; 95 if (!str || (p = copy = backslash(str)) == NULL) 96 return 1; 97 98 /* Initialize vector and state */ 99 clean(); 100 state = STR; 101 buf = (char *)malloc(PARSE_BUFSIZE); 102 token = 0; 103 104 /* And awaaaaaaaaay we go! */ 105 while (*p) { 106 switch (state) { 107 case STR: 108 if ((*p == '\\') && p[1]) { 109 p++; 110 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 111 buf[i++] = *p++; 112 } else if (isquote(*p)) { 113 quote = quote ? 0 : *p; 114 if (dquote) { /* keep quote */ 115 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 116 buf[i++] = *p++; 117 } else 118 ++p; 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 } else if (isspace(*p) && !quote && !dquote) { 127 state = WHITE; 128 if (i) { 129 buf[i] = '\0'; 130 PARSE_FAIL(insert(&ac, buf)); 131 i = 0; 132 } 133 ++p; 134 } else if (*p == '$' && !quote) { 135 token = isdelim(*(p + 1)); 136 if (token) 137 p += 2; 138 else 139 ++p; 140 state = VAR; 141 } else { 142 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 143 buf[i++] = *p++; 144 } 145 break; 146 147 case WHITE: 148 if (isspace(*p)) 149 ++p; 150 else 151 state = STR; 152 break; 153 154 case VAR: 155 if (token) { 156 PARSE_FAIL((q = strchr(p, token)) == NULL); 157 } else { 158 q = p; 159 while (*q && !isspace(*q)) 160 ++q; 161 } 162 tmp = *q; 163 *q = '\0'; 164 if ((val = variable_lookup(p)) != NULL) { 165 size_t len = strlen(val); 166 167 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1)); 168 i += min(len, PARSE_BUFSIZE - 1); 169 } 170 *q = tmp; /* restore value */ 171 p = q + (token ? 1 : 0); 172 state = STR; 173 break; 174 } 175 } 176 /* missing terminating ' or " */ 177 PARSE_FAIL(quote || dquote); 178 /* If at end of token, add it */ 179 if (i && state == STR) { 180 buf[i] = '\0'; 181 PARSE_FAIL(insert(&ac, buf)); 182 } 183 args[ac] = NULL; 184 *argc = ac; 185 *argv = (char **)malloc((sizeof(char *) * ac + 1)); 186 bcopy(args, *argv, sizeof(char *) * ac + 1); 187 free(buf); 188 free(copy); 189 return 0; 190 } 191 192 #define MAXARGS 20 193 194 /* Clean vector space */ 195 static void 196 clean(void) 197 { 198 int i; 199 200 for (i = 0; i < MAXARGS; i++) { 201 if (args[i] != NULL) { 202 free(args[i]); 203 args[i] = NULL; 204 } 205 } 206 } 207 208 static int 209 insert(int *argcp, char *buf) 210 { 211 212 if (*argcp >= MAXARGS) 213 return 1; 214 args[(*argcp)++] = strdup(buf); 215 return 0; 216 } 217 218 static char * 219 variable_lookup(char *name) 220 { 221 222 /* XXX search "special variable" space first? */ 223 return (char *)getenv(name); 224 } 225