grub/grub-core/script/lexer.c
2010-05-06 11:34:04 +05:30

346 lines
7.8 KiB
C

/* lexer.c - The scripting lexer. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2006,2007,2008,2009,2010 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/parser.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/script_sh.h>
#include "grub_script.tab.h"
#include "grub_script.yy.h"
void
grub_script_lexer_ref (struct grub_lexer_param *state)
{
state->refs++;
}
void
grub_script_lexer_deref (struct grub_lexer_param *state)
{
state->refs--;
}
/* Start recording all characters passing through the lexer. */
void
grub_script_lexer_record_start (struct grub_parser_param *parser)
{
struct grub_lexer_param *lexer = parser->lexerstate;
lexer->record = 1;
lexer->recordpos = 0;
if (lexer->recording) /* reuse last record */
return;
lexer->recordlen = GRUB_LEXER_INITIAL_RECORD_SIZE;
lexer->recording = grub_malloc (lexer->recordlen);
if (!lexer->recording)
{
grub_script_yyerror (parser, 0);
lexer->record = 0;
lexer->recordlen = 0;
}
}
char *
grub_script_lexer_record_stop (struct grub_parser_param *parser)
{
char *ptr;
char *result;
struct grub_lexer_param *lexer = parser->lexerstate;
auto char *compact (char *start, char *end);
char *compact (char *start, char *end)
{
/* Delete '{' and '}' characters and whitespaces. */
while (*start && grub_isspace (*start)) start++;
if (*start == '{') start++;
while (*start && grub_isspace (*start)) start++;
while (*end && grub_isspace (*end)) end--;
if (*end == '}') end--;
while (*end && grub_isspace (*end)) end--;
end[1] = '\0';
return start;
}
if (!lexer->record || !lexer->recording)
return 0;
/* XXX This is not necessary in BASH. */
ptr = compact (lexer->recording, lexer->recording + lexer->recordpos - 1);
lexer->record = 0;
lexer->recordpos = 0;
/* This memory would be freed by, grub_script_free. */
result = grub_script_malloc (parser, grub_strlen (ptr) + 1);
if (result)
grub_strcpy (result, ptr);
return result;
}
#define MAX(a,b) ((a) < (b) ? (b) : (a))
/* Record STR if input recording is enabled. */
void
grub_script_lexer_record (struct grub_parser_param *parser, char *str)
{
int len;
char *old;
struct grub_lexer_param *lexer = parser->lexerstate;
if (!lexer->record)
return;
len = grub_strlen (str);
if (lexer->recordpos + len + 1 > lexer->recordlen)
{
old = lexer->recording;
lexer->recordlen = MAX (len, lexer->recordlen) * 2;
lexer->recording = grub_realloc (lexer->recording, lexer->recordlen);
if (!lexer->recording)
{
grub_free (old);
lexer->record = 0;
lexer->recordpos = 0;
lexer->recordlen /= 2;
grub_script_yyerror (parser, 0);
return;
}
}
grub_strcpy (lexer->recording + lexer->recordpos, str);
lexer->recordpos += len;
}
/* Append '\n' to SRC, before '\0' */
static char *
append_newline (const char *src)
{
char *line;
grub_size_t len;
len = grub_strlen (src);
line = grub_malloc (len + 2);
if (!line)
return 0;
grub_strcpy (line, src);
line[len] = '\n';
line[len + 1] = '\0';
return line;
}
/* Read next line of input if necessary, and set yyscanner buffers. */
int
grub_script_lexer_yywrap (struct grub_parser_param *parserstate)
{
int len;
char *line;
char *line2;
YY_BUFFER_STATE buffer;
struct grub_lexer_param *lexerstate = parserstate->lexerstate;
if (!lexerstate->refs)
return 0;
if (!lexerstate->getline)
{
grub_script_yyerror (parserstate, "unexpected end of file");
return 0;
}
line = 0;
buffer = 0;
lexerstate->getline (&line, 1);
if (!line)
{
grub_script_yyerror (parserstate, 0); /* XXX this could be for ^C case? */
return 0;
}
len = grub_strlen (line);
if (line[len - 1] == '\n')
{
buffer = yy_scan_string (line, lexerstate->yyscanner);
}
else
{
line2 = append_newline (line);
if (line2)
{
buffer = yy_scan_string (line2, lexerstate->yyscanner);
grub_free (line2);
}
}
grub_free (line);
if (!buffer)
{
grub_script_yyerror (parserstate, 0);
return 0;
}
return 1;
}
struct grub_lexer_param *
grub_script_lexer_init (struct grub_parser_param *parser, char *script,
grub_reader_getline_t getline)
{
int len;
char *script2;
YY_BUFFER_STATE buffer;
struct grub_lexer_param *lexerstate;
lexerstate = grub_zalloc (sizeof (*lexerstate));
if (!lexerstate)
return 0;
lexerstate->size = GRUB_LEXER_INITIAL_TEXT_SIZE;
lexerstate->text = grub_malloc (lexerstate->size);
if (!lexerstate->text)
{
grub_free (lexerstate);
return 0;
}
lexerstate->getline = getline; /* rest are all zeros already */
if (yylex_init (&lexerstate->yyscanner))
{
grub_free (lexerstate->text);
grub_free (lexerstate);
return 0;
}
buffer = 0;
script = script ? : "\n";
len = grub_strlen (script);
if (script[len - 1] == '\n')
{
buffer = yy_scan_string (script, lexerstate->yyscanner);
}
else
{
script2 = append_newline (script);
if (script2)
{
buffer = yy_scan_string (script2, lexerstate->yyscanner);
grub_free (script2);
}
}
if (!buffer)
{
yylex_destroy (lexerstate->yyscanner);
grub_free (lexerstate->yyscanner);
grub_free (lexerstate->text);
grub_free (lexerstate);
return 0;
}
yyset_extra (parser, lexerstate->yyscanner);
return lexerstate;
}
void
grub_script_lexer_fini (struct grub_lexer_param *lexerstate)
{
if (!lexerstate)
return;
yylex_destroy (lexerstate->yyscanner);
grub_free (lexerstate->recording);
grub_free (lexerstate->text);
grub_free (lexerstate);
}
int
grub_script_yylex (union YYSTYPE *value,
struct grub_parser_param *parserstate)
{
char *str;
int token;
grub_script_arg_type_t type;
struct grub_lexer_param *lexerstate = parserstate->lexerstate;
value->arg = 0;
if (parserstate->err)
return GRUB_PARSER_TOKEN_BAD;
if (lexerstate->eof)
return GRUB_PARSER_TOKEN_EOF;
/*
* Words with environment variables, like foo${bar}baz needs
* multiple tokens to be merged into a single grub_script_arg. We
* use two variables to achieve this: lexerstate->merge_start and
* lexerstate->merge_end
*/
lexerstate->merge_start = 0;
lexerstate->merge_end = 0;
do
{
/* Empty lexerstate->text. */
lexerstate->used = 1;
lexerstate->text[0] = '\0';
token = yylex (value, lexerstate->yyscanner);
if (token == GRUB_PARSER_TOKEN_BAD)
break;
/* Merging feature uses lexerstate->text instead of yytext. */
if (lexerstate->merge_start)
{
str = lexerstate->text;
type = lexerstate->type;
}
else
{
str = yyget_text (lexerstate->yyscanner);
type = GRUB_SCRIPT_ARG_TYPE_TEXT;
}
grub_dprintf("lexer", "token %u text [%s]\n", token, str);
value->arg = grub_script_arg_add (parserstate, value->arg, type, str);
}
while (lexerstate->merge_start && !lexerstate->merge_end);
if (!value->arg || parserstate->err)
return GRUB_PARSER_TOKEN_BAD;
return token;
}
void
grub_script_yyerror (struct grub_parser_param *state, char const *err)
{
if (err)
grub_error (GRUB_ERR_INVALID_COMMAND, err);
grub_print_error ();
state->err++;
}