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 * $FreeBSD: src/sys/boot/common/interp_parse.c,v 1.10 2003/08/25 23:30:41 obrien Exp $ 17 * $DragonFly: src/sys/boot/common/interp_parse.c,v 1.3 2003/11/10 06:08:31 dillon Exp $ 18 */ 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 if (ch == '{') 66 return '}'; 67 else if (ch == '(') 68 return ')'; 69 return '\0'; 70 } 71 72 static int 73 isquote(int ch) 74 { 75 return (ch == '\'' || ch == '"'); 76 } 77 78 int 79 parse(int *argc, char ***argv, char *str) 80 { 81 int ac; 82 char *val, *p, *q, *copy = NULL; 83 size_t i = 0; 84 char token, tmp, quote, *buf; 85 enum { STR, VAR, WHITE } state; 86 87 ac = *argc = 0; 88 quote = 0; 89 if (!str || (p = copy = backslash(str)) == NULL) 90 return 1; 91 92 /* Initialize vector and state */ 93 clean(); 94 state = STR; 95 buf = (char *)malloc(PARSE_BUFSIZE); 96 token = 0; 97 98 /* And awaaaaaaaaay we go! */ 99 while (*p) { 100 switch (state) { 101 case STR: 102 /* 103 * Check comment 104 */ 105 if (*p == '#' && quote == 0) { 106 *p = 0; 107 break; 108 } 109 110 /* 111 * Check line continuation 112 */ 113 if (*p == '\\' && p[1]) { 114 p++; 115 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 116 buf[i++] = *p++; 117 } else if (isquote(*p)) { 118 quote = quote ? 0 : *p; 119 ++p; 120 } 121 else if (isspace(*p) && !quote) { 122 state = WHITE; 123 if (i) { 124 buf[i] = '\0'; 125 PARSE_FAIL(insert(&ac, buf)); 126 i = 0; 127 } 128 ++p; 129 } else if (*p == '$') { 130 token = isdelim(*(p + 1)); 131 if (token) 132 p += 2; 133 else 134 ++p; 135 state = VAR; 136 } else { 137 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 138 buf[i++] = *p++; 139 } 140 break; 141 142 case WHITE: 143 if (isspace(*p)) 144 ++p; 145 else 146 state = STR; 147 break; 148 149 case VAR: 150 if (token) { 151 PARSE_FAIL((q = index(p, token)) == NULL); 152 } else { 153 q = p; 154 while (*q && !isspace(*q)) 155 ++q; 156 } 157 tmp = *q; 158 *q = '\0'; 159 if ((val = variable_lookup(p)) != NULL) { 160 size_t len = strlen(val); 161 162 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1)); 163 i += min(len, PARSE_BUFSIZE - 1); 164 } 165 *q = tmp; /* restore value */ 166 p = q + (token ? 1 : 0); 167 state = STR; 168 break; 169 } 170 } 171 /* If at end of token, add it */ 172 if (i && state == STR) { 173 buf[i] = '\0'; 174 PARSE_FAIL(insert(&ac, buf)); 175 } 176 args[ac] = NULL; 177 *argc = ac; 178 *argv = (char **)malloc(sizeof(char *) * (ac + 1)); 179 bcopy(args, *argv, sizeof(char *) * (ac + 1)); 180 free(buf); 181 free(copy); 182 return 0; 183 } 184 185 #define MAXARGS 20 186 187 /* Clean vector space */ 188 static void 189 clean(void) 190 { 191 int i; 192 193 for (i = 0; i < MAXARGS; i++) { 194 if (args[i] != NULL) { 195 free(args[i]); 196 args[i] = NULL; 197 } 198 } 199 } 200 201 static int 202 insert(int *argcp, char *buf) 203 { 204 if (*argcp >= MAXARGS) 205 return 1; 206 args[(*argcp)++] = strdup(buf); 207 return 0; 208 } 209 210 static char * 211 variable_lookup(char *name) 212 { 213 /* XXX search "special variable" space first? */ 214 return (char *)getenv(name); 215 } 216