sys/arch/ia64/stand/common/interp_parse.c

   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 $"); */
  21
  22 #include <lib/libsa/stand.h>
  23 #include <lib/libsa/loadfile.h>
  24 #include <lib/libkern/libkern.h>
  25
  26 #include "bootstrap.h"
  27
  28 static void      clean(void);
  29 static int       insert(int *argcp, char *buf);
  30 static char     *variable_lookup(char *name);
  31
  32 #define PARSE_BUFSIZE   1024    /* maximum size of one element */
  33 #define MAXARGS         20      /* maximum number of elements */
  34 static char             *args[MAXARGS];
  35
  36 /*
  37  * parse: accept a string of input and "parse" it for backslash
  38  * substitutions and environment variable expansions (${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) \
  57 if (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 */
  66 static char
  67 isdelim(int ch)
  68 {
  69     if (ch == '{')
  70         return '}';
  71     else if (ch == '(')
  72         return ')';
  73     return '\0';
  74 }
  75
  76 static int
  77 isquote(int ch)
  78 {
  79     return (ch == '\'' || ch == '"');
  80 }
  81
  82 int
  83 parse(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 */
 181 static void
 182 clean(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
 194 static int
 195 insert(int *argcp, char *buf)
 196 {
 197     if (*argcp >= MAXARGS)
 198         return 1;
 199     args[(*argcp)++] = strdup(buf);
 200     return 0;
 201 }
 202
 203 static char *
 204 variable_lookup(char *name)
 205 {
 206     /* XXX search "special variable" space first? */
 207     return (char *)getenv(name);
 208 }