1/* $NetBSD: interp_parse.c,v 1.4 2009/07/20 04:59:03 kiyohara Exp $ */ 2 3/*- 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * Jordan K. Hubbard 14 * 29 August 1998 15 * 16 * The meat of the simple parser. 17 */ 18 19#include <sys/cdefs.h> 20/* __FBSDID("$FreeBSD: src/sys/boot/common/interp_parse.c,v 1.10 2003/08/25 23:30:41 obrien Exp $"); */ 21 22#include <lib/libsa/stand.h> 23#include <lib/libsa/loadfile.h> 24#include <lib/libkern/libkern.h> 25 26#include "bootstrap.h" 27 28static void clean(void); 29static int insert(int *argcp, char *buf); 30static char *variable_lookup(char *name); 31 32#define PARSE_BUFSIZE 1024 /* maximum size of one element */ 33#define MAXARGS 20 /* maximum number of elements */ 34static char *args[MAXARGS]; 35 36/* 37 * parse: accept a string of input and "parse" it for backslash 38 * substitutions and environment variable expansions (${var}), 39 * returning an argc/argv style vector of whitespace separated 40 * arguments. Returns 0 on success, 1 on failure (ok, ok, so I 41 * wimped-out on the error codes! :). 42 * 43 * Note that the argv array returned must be freed by the caller, but 44 * we own the space allocated for arguments and will free that on next 45 * invocation. This allows argv consumers to modify the array if 46 * required. 47 * 48 * NB: environment variables that expand to more than one whitespace 49 * separated token will be returned as a single argv[] element, not 50 * split in turn. Expanded text is also immune to further backslash 51 * elimination or expansion since this is a one-pass, non-recursive 52 * parser. You didn't specify more than this so if you want more, ask 53 * me. - jkh 54 */ 55 56#define PARSE_FAIL(expr) \ 57if (expr) { \ 58 printf("fail at line %d\n", __LINE__); \ 59 clean(); \ 60 free(copy); \ 61 free(buf); \ 62 return 1; \ 63} 64 65/* Accept the usual delimiters for a variable, returning counterpart */ 66static char 67isdelim(int ch) 68{ 69 if (ch == '{') 70 return '}'; 71 else if (ch == '(') 72 return ')'; 73 return '\0'; 74} 75 76static int 77isquote(int ch) 78{ 79 return (ch == '\'' || ch == '"'); 80} 81 82int 83parse(int *argc, char ***argv, char *str) 84{ 85 int ac; 86 char *val, *p, *q, *copy = NULL; 87 size_t i = 0; 88 char token, tmp, quote, *buf; 89 enum { STR, VAR, WHITE } state; 90 91 ac = *argc = 0; 92 quote = 0; 93 if (!str || (p = copy = backslash(str)) == NULL) 94 return 1; 95 96 /* Initialize vector and state */ 97 clean(); 98 state = STR; 99 buf = (char *)alloc(PARSE_BUFSIZE); 100 token = 0; 101 102 /* And awaaaaaaaaay we go! */ 103 while (*p) { 104 switch (state) { 105 case STR: 106 if ((*p == '\\') && p[1]) { 107 p++; 108 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 109 buf[i++] = *p++; 110 } else if (isquote(*p)) { 111 quote = quote ? 0 : *p; 112 ++p; 113 } 114 else if (isspace(*p) && !quote) { 115 state = WHITE; 116 if (i) { 117 buf[i] = '\0'; 118 PARSE_FAIL(insert(&ac, buf)); 119 i = 0; 120 } 121 ++p; 122 } else if (*p == '$') { 123 token = isdelim(*(p + 1)); 124 if (token) 125 p += 2; 126 else 127 ++p; 128 state = VAR; 129 } else { 130 PARSE_FAIL(i == (PARSE_BUFSIZE - 1)); 131 buf[i++] = *p++; 132 } 133 break; 134 135 case WHITE: 136 if (isspace(*p)) 137 ++p; 138 else 139 state = STR; 140 break; 141 142 case VAR: 143 if (token) { 144 PARSE_FAIL((q = strchr(p, token)) == NULL); 145 } else { 146 q = p; 147 while (*q && !isspace(*q)) 148 ++q; 149 } 150 tmp = *q; 151 *q = '\0'; 152 if ((val = variable_lookup(p)) != NULL) { 153 size_t len = strlen(val); 154 155 strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1)); 156 i += min(len, PARSE_BUFSIZE - 1); 157 } 158 *q = tmp; /* restore value */ 159 p = q + (token ? 1 : 0); 160 state = STR; 161 break; 162 } 163 } 164 /* If at end of token, add it */ 165 if (i && state == STR) { 166 buf[i] = '\0'; 167 PARSE_FAIL(insert(&ac, buf)); 168 } 169 args[ac] = NULL; 170 *argc = ac; 171 *argv = (char **)alloc((sizeof(char *) * ac + 1)); 172 memcpy(*argv, args, sizeof(char *) * ac + 1); 173 free(buf); 174 free(copy); 175 return 0; 176} 177 178#define MAXARGS 20 179 180/* Clean vector space */ 181static void 182clean(void) 183{ 184 int i; 185 186 for (i = 0; i < MAXARGS; i++) { 187 if (args[i] != NULL) { 188 free(args[i]); 189 args[i] = NULL; 190 } 191 } 192} 193 194static int 195insert(int *argcp, char *buf) 196{ 197 if (*argcp >= MAXARGS) 198 return 1; 199 args[(*argcp)++] = strdup(buf); 200 return 0; 201} 202 203static char * 204variable_lookup(char *name) 205{ 206 /* XXX search "special variable" space first? */ 207 return (char *)getenv(name); 208} 209