/* parser.c - the part of the parser that can return partial tokens */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2007,2009,2021 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 .
*/
#include
#include
#include
#include
#include
/* All the possible state transitions on the command line. If a
transition can not be found, it is assumed that there is no
transition and keep_value is assumed to be 1. */
static struct grub_parser_state_transition state_transitions[] = {
{GRUB_PARSER_STATE_TEXT, GRUB_PARSER_STATE_QUOTE, '\'', 0},
{GRUB_PARSER_STATE_TEXT, GRUB_PARSER_STATE_DQUOTE, '\"', 0},
{GRUB_PARSER_STATE_TEXT, GRUB_PARSER_STATE_VAR, '$', 0},
{GRUB_PARSER_STATE_TEXT, GRUB_PARSER_STATE_ESC, '\\', 0},
{GRUB_PARSER_STATE_ESC, GRUB_PARSER_STATE_TEXT, 0, 1},
{GRUB_PARSER_STATE_QUOTE, GRUB_PARSER_STATE_TEXT, '\'', 0},
{GRUB_PARSER_STATE_DQUOTE, GRUB_PARSER_STATE_TEXT, '\"', 0},
{GRUB_PARSER_STATE_DQUOTE, GRUB_PARSER_STATE_QVAR, '$', 0},
{GRUB_PARSER_STATE_VAR, GRUB_PARSER_STATE_VARNAME2, '{', 0},
{GRUB_PARSER_STATE_VAR, GRUB_PARSER_STATE_VARNAME, 0, 1},
{GRUB_PARSER_STATE_VARNAME, GRUB_PARSER_STATE_TEXT, ' ', 1},
{GRUB_PARSER_STATE_VARNAME, GRUB_PARSER_STATE_TEXT, '\t', 1},
{GRUB_PARSER_STATE_VARNAME2, GRUB_PARSER_STATE_TEXT, '}', 0},
{GRUB_PARSER_STATE_QVAR, GRUB_PARSER_STATE_QVARNAME2, '{', 0},
{GRUB_PARSER_STATE_QVAR, GRUB_PARSER_STATE_QVARNAME, 0, 1},
{GRUB_PARSER_STATE_QVARNAME, GRUB_PARSER_STATE_TEXT, '\"', 0},
{GRUB_PARSER_STATE_QVARNAME, GRUB_PARSER_STATE_DQUOTE, ' ', 1},
{GRUB_PARSER_STATE_QVARNAME, GRUB_PARSER_STATE_DQUOTE, '\t', 1},
{GRUB_PARSER_STATE_QVARNAME2, GRUB_PARSER_STATE_DQUOTE, '}', 0},
{0, 0, 0, 0}
};
/* Determines the state following STATE, determined by C. */
grub_parser_state_t
grub_parser_cmdline_state (grub_parser_state_t state, char c, char *result)
{
struct grub_parser_state_transition *transition;
struct grub_parser_state_transition default_transition;
default_transition.to_state = state;
default_transition.keep_value = 1;
/* Look for a good translation. */
for (transition = state_transitions; transition->from_state; transition++)
{
if (transition->from_state != state)
continue;
/* An exact match was found, use it. */
if (transition->input == c)
break;
if (grub_isspace (transition->input) && !grub_isalpha (c)
&& !grub_isdigit (c) && c != '_')
break;
/* A less perfect match was found, use this one if no exact
match can be found. */
if (transition->input == 0)
break;
}
if (!transition->from_state)
transition = &default_transition;
if (transition->keep_value)
*result = c;
else
*result = 0;
return transition->to_state;
}
/* Helper for grub_parser_split_cmdline. */
static inline int
check_varstate (grub_parser_state_t s)
{
return (s == GRUB_PARSER_STATE_VARNAME
|| s == GRUB_PARSER_STATE_VARNAME2
|| s == GRUB_PARSER_STATE_QVARNAME
|| s == GRUB_PARSER_STATE_QVARNAME2);
}
static grub_err_t
add_var (grub_buffer_t varname, grub_buffer_t buf,
grub_parser_state_t state, grub_parser_state_t newstate)
{
const char *val;
/* Check if a variable was being read in and the end of the name
was reached. */
if (!(check_varstate (state) && !check_varstate (newstate)))
return GRUB_ERR_NONE;
if (grub_buffer_append_char (varname, '\0') != GRUB_ERR_NONE)
return grub_errno;
val = grub_env_get ((const char *) grub_buffer_peek_data (varname));
grub_buffer_reset (varname);
if (!val)
return GRUB_ERR_NONE;
/* Insert the contents of the variable in the buffer. */
return grub_buffer_append_data (buf, val, grub_strlen (val));
}
static grub_err_t
terminate_arg (grub_buffer_t buffer, int *argc)
{
grub_size_t unread = grub_buffer_get_unread_bytes (buffer);
if (unread == 0)
return GRUB_ERR_NONE;
if (*(const char *) grub_buffer_peek_data_at (buffer, unread - 1) == '\0')
return GRUB_ERR_NONE;
if (grub_buffer_append_char (buffer, '\0') != GRUB_ERR_NONE)
return grub_errno;
(*argc)++;
return GRUB_ERR_NONE;
}
static grub_err_t
process_char (char c, grub_buffer_t buffer, grub_buffer_t varname,
grub_parser_state_t state, int *argc,
grub_parser_state_t *newstate)
{
char use;
*newstate = grub_parser_cmdline_state (state, c, &use);
/*
* If a variable was being processed and this character does
* not describe the variable anymore, write the variable to
* the buffer.
*/
if (add_var (varname, buffer, state, *newstate) != GRUB_ERR_NONE)
return grub_errno;
if (check_varstate (*newstate))
{
if (use)
return grub_buffer_append_char (varname, use);
}
else if (*newstate == GRUB_PARSER_STATE_TEXT &&
state != GRUB_PARSER_STATE_ESC && grub_isspace (use))
{
/*
* Don't add more than one argument if multiple
* spaces are used.
*/
return terminate_arg (buffer, argc);
}
else if (use)
return grub_buffer_append_char (buffer, use);
return GRUB_ERR_NONE;
}
grub_err_t
grub_parser_split_cmdline (const char *cmdline,
grub_reader_getline_t getline, void *getline_data,
int *argc, char ***argv)
{
grub_parser_state_t state = GRUB_PARSER_STATE_TEXT;
grub_buffer_t buffer, varname;
char *rd = (char *) cmdline;
char *rp = rd;
int i;
*argc = 0;
*argv = NULL;
buffer = grub_buffer_new (1024);
if (buffer == NULL)
return grub_errno;
varname = grub_buffer_new (200);
if (varname == NULL)
goto fail;
do
{
if (rp == NULL || *rp == '\0')
{
if (rd != cmdline)
{
grub_free (rd);
rd = rp = NULL;
}
if (getline)
{
getline (&rd, 1, getline_data);
rp = rd;
}
else
break;
}
if (!rd)
break;
for (; *rp != '\0'; rp++)
{
grub_parser_state_t newstate;
if (process_char (*rp, buffer, varname, state, argc,
&newstate) != GRUB_ERR_NONE)
goto fail;
state = newstate;
}
}
while (state != GRUB_PARSER_STATE_TEXT && !check_varstate (state));
/* A special case for when the last character was part of a
variable. */
if (add_var (varname, buffer, state, GRUB_PARSER_STATE_TEXT) != GRUB_ERR_NONE)
goto fail;
/* Ensure that the last argument is terminated. */
if (terminate_arg (buffer, argc) != GRUB_ERR_NONE)
goto fail;
/* If there are no args, then we're done. */
if (!*argc)
{
grub_errno = GRUB_ERR_NONE;
goto out;
}
*argv = grub_calloc (*argc + 1, sizeof (char *));
if (!*argv)
goto fail;
/* The arguments are separated with 0's, setup argv so it points to
the right values. */
for (i = 0; i < *argc; i++)
{
char *arg;
if (i > 0)
{
if (grub_buffer_advance_read_pos (buffer, 1) != GRUB_ERR_NONE)
goto fail;
}
arg = (char *) grub_buffer_peek_data (buffer);
if (arg == NULL ||
grub_buffer_advance_read_pos (buffer, grub_strlen (arg)) != GRUB_ERR_NONE)
goto fail;
(*argv)[i] = arg;
}
/* Keep memory for the return values. */
grub_buffer_take_data (buffer);
grub_errno = GRUB_ERR_NONE;
out:
if (rd != cmdline)
grub_free (rd);
grub_buffer_free (buffer);
grub_buffer_free (varname);
return grub_errno;
fail:
grub_free (*argv);
goto out;
}
/* Helper for grub_parser_execute. */
static grub_err_t
grub_parser_execute_getline (char **line, int cont __attribute__ ((unused)),
void *data)
{
char **source = data;
char *p;
if (!*source)
{
*line = 0;
return 0;
}
p = grub_strchr (*source, '\n');
if (p)
*line = grub_strndup (*source, p - *source);
else
*line = grub_strdup (*source);
*source = p ? p + 1 : 0;
return 0;
}
grub_err_t
grub_parser_execute (char *source)
{
while (source)
{
char *line;
grub_parser_execute_getline (&line, 0, &source);
grub_rescue_parse_line (line, grub_parser_execute_getline, &source);
grub_free (line);
grub_print_error ();
}
return grub_errno;
}