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>
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18__FBSDID("$FreeBSD: head/sys/boot/common/interp_parse.c 119483 2003-08-25 23:30:41Z obrien $");
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18__FBSDID("$FreeBSD: head/sys/boot/common/interp_parse.c 229403 2012-01-03 18:51:58Z ed $"); |
19 20#include <stand.h> 21#include <string.h> 22#include "bootstrap.h" 23 24static void clean(void); 25static int insert(int *argcp, char *buf); 26static char *variable_lookup(char *name); 27 28#define PARSE_BUFSIZE 1024 /* maximum size of one element */ 29#define MAXARGS 20 /* maximum number of elements */ 30static char *args[MAXARGS]; 31 32/* 33 * parse: accept a string of input and "parse" it for backslash 34 * substitutions and environment variable expansions (${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) \ 53if (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 */ 62static char 63isdelim(int ch) 64{ 65 if (ch == '{') 66 return '}'; 67 else if (ch == '(') 68 return ')'; 69 return '\0'; 70} 71 72static int 73isquote(int ch) 74{ 75 return (ch == '\'' || ch == '"'); 76} 77 78int 79parse(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 if ((*p == '\\') && p[1]) { 103 p++; 104 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 105 buf[i++] = *p++; 106 } else if (isquote(*p)) { 107 quote = quote ? 0 : *p; 108 ++p; 109 } 110 else if (isspace(*p) && !quote) { 111 state = WHITE; 112 if (i) { 113 buf[i] = '\0'; 114 PARSE_FAIL(insert(&ac, buf)); 115 i = 0; 116 } 117 ++p; 118 } else if (*p == '$') { 119 token = isdelim(*(p + 1)); 120 if (token) 121 p += 2; 122 else 123 ++p; 124 state = VAR; 125 } else { 126 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 127 buf[i++] = *p++; 128 } 129 break; 130 131 case WHITE: 132 if (isspace(*p)) 133 ++p; 134 else 135 state = STR; 136 break; 137 138 case VAR: 139 if (token) {
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140 PARSE_FAIL((q = index(p, token)) == NULL);
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140 PARSE_FAIL((q = strchr(p, token)) == NULL); |
141 } else { 142 q = p; 143 while (*q && !isspace(*q)) 144 ++q; 145 } 146 tmp = *q; 147 *q = '\0'; 148 if ((val = variable_lookup(p)) != NULL) { 149 size_t len = strlen(val); 150 151 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1)); 152 i += min(len, PARSE_BUFSIZE - 1); 153 } 154 *q = tmp; /* restore value */ 155 p = q + (token ? 1 : 0); 156 state = STR; 157 break; 158 } 159 } 160 /* If at end of token, add it */ 161 if (i && state == STR) { 162 buf[i] = '\0'; 163 PARSE_FAIL(insert(&ac, buf)); 164 } 165 args[ac] = NULL; 166 *argc = ac; 167 *argv = (char **)malloc((sizeof(char *) * ac + 1)); 168 bcopy(args, *argv, sizeof(char *) * ac + 1); 169 free(buf); 170 free(copy); 171 return 0; 172} 173 174#define MAXARGS 20 175 176/* Clean vector space */ 177static void 178clean(void) 179{ 180 int i; 181 182 for (i = 0; i < MAXARGS; i++) { 183 if (args[i] != NULL) { 184 free(args[i]); 185 args[i] = NULL; 186 } 187 } 188} 189 190static int 191insert(int *argcp, char *buf) 192{ 193 if (*argcp >= MAXARGS) 194 return 1; 195 args[(*argcp)++] = strdup(buf); 196 return 0; 197} 198 199static char * 200variable_lookup(char *name) 201{ 202 /* XXX search "special variable" space first? */ 203 return (char *)getenv(name); 204}
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