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grub/grub-core/script/execute.c
Chris Coulson 426f57383d script: Avoid a use-after-free when redefining a function during execution 
Defining a new function with the same name as a previously defined
function causes the grub_script and associated resources for the
previous function to be freed. If the previous function is currently
executing when a function with the same name is defined, this results
in use-after-frees when processing subsequent commands in the original
function.

Instead, reject a new function definition if it has the same name as
a previously defined function, and that function is currently being
executed. Although a behavioural change, this should be backwards
compatible with existing configurations because they can't be
dependent on the current behaviour without being broken.

Fixes: CVE-2020-15706

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-07-29 16:55:48 +02:00

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/* execute.c -- Execute a GRUB script. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2007,2008,2009,2010 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/misc.h>
#include <grub/mm.h>
#include <grub/env.h>
#include <grub/script_sh.h>
#include <grub/command.h>
#include <grub/menu.h>
#include <grub/lib/arg.h>
#include <grub/normal.h>
#include <grub/extcmd.h>
#include <grub/i18n.h>
#include <grub/verify.h>
/* Max digits for a char is 3 (0xFF is 255), similarly for an int it
is sizeof (int) * 3, and one extra for a possible -ve sign. */
#define ERRNO_DIGITS_MAX (sizeof (int) * 3 + 1)
static unsigned long is_continue;
static unsigned long active_loops;
static unsigned long active_breaks;
static unsigned long function_return;
#define GRUB_SCRIPT_SCOPE_MALLOCED 1
#define GRUB_SCRIPT_SCOPE_ARGS_MALLOCED 2
/* Scope for grub script functions. */
struct grub_script_scope
{
unsigned flags;
unsigned shifts;
struct grub_script_argv argv;
};
static struct grub_script_scope *scope = 0;
/* Wildcard translator for GRUB script. */
struct grub_script_wildcard_translator *grub_wildcard_translator;
static char*
wildcard_escape (const char *s)
{
int i;
int len;
char ch;
char *p;
len = grub_strlen (s);
p = grub_malloc (len * 2 + 1);
if (! p)
return NULL;
i = 0;
while ((ch = *s++))
{
if (ch == '*' || ch == '\\' || ch == '?')
p[i++] = '\\';
p[i++] = ch;
}
p[i] = '\0';
return p;
}
static char*
wildcard_unescape (const char *s)
{
int i;
int len;
char ch;
char *p;
len = grub_strlen (s);
p = grub_malloc (len + 1);
if (! p)
return NULL;
i = 0;
while ((ch = *s++))
{
if (ch == '\\')
p[i++] = *s++;
else
p[i++] = ch;
}
p[i] = '\0';
return p;
}
static void
replace_scope (struct grub_script_scope *new_scope)
{
if (scope)
{
scope->argv.argc += scope->shifts;
scope->argv.args -= scope->shifts;
if (scope->flags & GRUB_SCRIPT_SCOPE_ARGS_MALLOCED)
grub_script_argv_free (&scope->argv);
if (scope->flags & GRUB_SCRIPT_SCOPE_MALLOCED)
grub_free (scope);
}
scope = new_scope;
}
grub_err_t
grub_script_break (grub_command_t cmd, int argc, char *argv[])
{
const char *p = NULL;
unsigned long count;
if (argc == 0)
count = 1;
else if (argc > 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
else
{
count = grub_strtoul (argv[0], &p, 10);
if (grub_errno)
return grub_errno;
if (*p != '\0')
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("unrecognized number"));
if (count == 0)
/* TRANSLATORS: 0 is a quantifier. "break" (similar to bash)
can be used e.g. to break 3 loops at once.
But asking it to break 0 loops makes no sense. */
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("can't break 0 loops"));
}
is_continue = grub_strcmp (cmd->name, "break") ? 1 : 0;
active_breaks = count;
if (active_breaks > active_loops)
active_breaks = active_loops;
return GRUB_ERR_NONE;
}
grub_err_t
grub_script_shift (grub_command_t cmd __attribute__((unused)),
int argc, char *argv[])
{
const char *p = NULL;
unsigned long n = 0;
if (! scope)
return GRUB_ERR_NONE;
if (argc == 0)
n = 1;
else if (argc > 1)
return GRUB_ERR_BAD_ARGUMENT;
else
{
n = grub_strtoul (argv[0], &p, 10);
if (*p != '\0')
return GRUB_ERR_BAD_ARGUMENT;
}
if (n > scope->argv.argc)
return GRUB_ERR_BAD_ARGUMENT;
scope->shifts += n;
scope->argv.argc -= n;
scope->argv.args += n;
return GRUB_ERR_NONE;
}
grub_err_t
grub_script_setparams (grub_command_t cmd __attribute__((unused)),
int argc, char **args)
{
struct grub_script_scope *new_scope;
struct grub_script_argv argv = { 0, 0, 0 };
if (! scope)
return GRUB_ERR_INVALID_COMMAND;
new_scope = grub_malloc (sizeof (*new_scope));
if (! new_scope)
return grub_errno;
if (grub_script_argv_make (&argv, argc, args))
{
grub_free (new_scope);
return grub_errno;
}
new_scope->shifts = 0;
new_scope->argv = argv;
new_scope->flags = GRUB_SCRIPT_SCOPE_MALLOCED |
GRUB_SCRIPT_SCOPE_ARGS_MALLOCED;
replace_scope (new_scope);
return GRUB_ERR_NONE;
}
grub_err_t
grub_script_return (grub_command_t cmd __attribute__((unused)),
int argc, char *argv[])
{
const char *p = NULL;
unsigned long n;
if (! scope || argc > 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
/* TRANSLATORS: It's about not being
inside a function. "return" can be used only
in a function and this error occurs if it's used
anywhere else. */
N_("not in function body"));
if (argc == 0)
{
const char *t;
function_return = 1;
t = grub_env_get ("?");
if (!t)
return GRUB_ERR_NONE;
return grub_strtoul (t, NULL, 10);
}
n = grub_strtoul (argv[0], &p, 10);
if (grub_errno)
return grub_errno;
if (*p != '\0')
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("unrecognized number"));
function_return = 1;
return n ? grub_error (n, N_("false")) : GRUB_ERR_NONE;
}
static int
grub_env_special (const char *name)
{
if (grub_isdigit (name[0]) ||
grub_strcmp (name, "#") == 0 ||
grub_strcmp (name, "*") == 0 ||
grub_strcmp (name, "@") == 0)
return 1;
return 0;
}
static char **
grub_script_env_get (const char *name, grub_script_arg_type_t type)
{
unsigned i;
struct grub_script_argv result = { 0, 0, 0 };
if (grub_script_argv_next (&result))
goto fail;
if (! grub_env_special (name))
{
const char *v = grub_env_get (name);
if (v && v[0])
{
if (type == GRUB_SCRIPT_ARG_TYPE_VAR)
{
if (grub_script_argv_split_append (&result, v))
goto fail;
}
else
if (grub_script_argv_append (&result, v, grub_strlen (v)))
goto fail;
}
}
else if (! scope)
{
if (grub_script_argv_append (&result, 0, 0))
goto fail;
}
else if (grub_strcmp (name, "#") == 0)
{
char buffer[ERRNO_DIGITS_MAX + 1];
grub_snprintf (buffer, sizeof (buffer), "%u", scope->argv.argc);
if (grub_script_argv_append (&result, buffer, grub_strlen (buffer)))
goto fail;
}
else if (grub_strcmp (name, "*") == 0)
{
for (i = 0; i < scope->argv.argc; i++)
if (type == GRUB_SCRIPT_ARG_TYPE_VAR)
{
if (i != 0 && grub_script_argv_next (&result))
goto fail;
if (grub_script_argv_split_append (&result, scope->argv.args[i]))
goto fail;
}
else
{
if (i != 0 && grub_script_argv_append (&result, " ", 1))
goto fail;
if (grub_script_argv_append (&result, scope->argv.args[i],
grub_strlen (scope->argv.args[i])))
goto fail;
}
}
else if (grub_strcmp (name, "@") == 0)
{
for (i = 0; i < scope->argv.argc; i++)
{
if (i != 0 && grub_script_argv_next (&result))
goto fail;
if (type == GRUB_SCRIPT_ARG_TYPE_VAR)
{
if (grub_script_argv_split_append (&result, scope->argv.args[i]))
goto fail;
}
else
if (grub_script_argv_append (&result, scope->argv.args[i],
grub_strlen (scope->argv.args[i])))
goto fail;
}
}
else
{
unsigned long num = grub_strtoul (name, 0, 10);
if (num == 0)
; /* XXX no file name, for now. */
else if (num <= scope->argv.argc)
{
if (type == GRUB_SCRIPT_ARG_TYPE_VAR)
{
if (grub_script_argv_split_append (&result,
scope->argv.args[num - 1]))
goto fail;
}
else
if (grub_script_argv_append (&result, scope->argv.args[num - 1],
grub_strlen (scope->argv.args[num - 1])
))
goto fail;
}
}
return result.args;
fail:
grub_script_argv_free (&result);
return 0;
}
static grub_err_t
grub_script_env_set (const char *name, const char *val)
{
if (grub_env_special (name))
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("invalid variable name `%s'"), name);
return grub_env_set (name, val);
}
struct gettext_context
{
char **allowed_strings;
grub_size_t nallowed_strings;
grub_size_t additional_len;
};
static int
parse_string (const char *str,
int (*hook) (const char *var, grub_size_t varlen,
char **ptr, struct gettext_context *ctx),
struct gettext_context *ctx,
char *put)
{
const char *ptr;
int escaped = 0;
const char *optr;
for (ptr = str; ptr && *ptr; )
switch (*ptr)
{
case '\\':
escaped = !escaped;
if (!escaped && put)
*(put++) = '\\';
ptr++;
break;
case '$':
if (escaped)
{
escaped = 0;
if (put)
*(put++) = *ptr;
ptr++;
break;
}
ptr++;
switch (*ptr)
{
case '{':
{
optr = ptr + 1;
ptr = grub_strchr (optr, '}');
if (!ptr)
break;
if (hook (optr, ptr - optr, &put, ctx))
return 1;
ptr++;
break;
}
case '0' ... '9':
optr = ptr;
while (*ptr >= '0' && *ptr <= '9')
ptr++;
if (hook (optr, ptr - optr, &put, ctx))
return 1;
break;
case 'a' ... 'z':
case 'A' ... 'Z':
case '_':
optr = ptr;
while ((*ptr >= '0' && *ptr <= '9')
|| (*ptr >= 'a' && *ptr <= 'z')
|| (*ptr >= 'A' && *ptr <= 'Z')
|| *ptr == '_')
ptr++;
if (hook (optr, ptr - optr, &put, ctx))
return 1;
break;
case '?':
case '#':
if (hook (ptr, 1, &put, ctx))
return 1;
ptr++;
break;
default:
if (put)
*(put++) = '$';
}
break;
default:
if (escaped && put)
*(put++) = '\\';
escaped = 0;
if (put)
*(put++) = *ptr;
ptr++;
break;
}
if (put)
*(put++) = 0;
return 0;
}
static int
gettext_putvar (const char *str, grub_size_t len,
char **ptr, struct gettext_context *ctx)
{
const char *var;
grub_size_t i;
for (i = 0; i < ctx->nallowed_strings; i++)
if (grub_strncmp (ctx->allowed_strings[i], str, len) == 0
&& ctx->allowed_strings[i][len] == 0)
{
break;
}
if (i == ctx->nallowed_strings)
return 0;
/* Enough for any number. */
if (len == 1 && str[0] == '#')
{
grub_snprintf (*ptr, 30, "%u", scope->argv.argc);
*ptr += grub_strlen (*ptr);
return 0;
}
var = grub_env_get (ctx->allowed_strings[i]);
if (var)
*ptr = grub_stpcpy (*ptr, var);
return 0;
}
static int
gettext_save_allow (const char *str, grub_size_t len,
char **ptr __attribute__ ((unused)),
struct gettext_context *ctx)
{
ctx->allowed_strings[ctx->nallowed_strings++] = grub_strndup (str, len);
if (!ctx->allowed_strings[ctx->nallowed_strings - 1])
return 1;
return 0;
}
static int
gettext_getlen (const char *str, grub_size_t len,
char **ptr __attribute__ ((unused)),
struct gettext_context *ctx)
{
const char *var;
grub_size_t i;
for (i = 0; i < ctx->nallowed_strings; i++)
if (grub_strncmp (ctx->allowed_strings[i], str, len) == 0
&& ctx->allowed_strings[i][len] == 0)
break;
if (i == ctx->nallowed_strings)
return 0;
/* Enough for any number. */
if (len == 1 && str[0] == '#')
{
ctx->additional_len += 30;
return 0;
}
var = grub_env_get (ctx->allowed_strings[i]);
if (var)
ctx->additional_len += grub_strlen (var);
return 0;
}
static int
gettext_append (struct grub_script_argv *result, const char *orig_str)
{
const char *template;
char *res = 0;
struct gettext_context ctx = {
.allowed_strings = 0,
.nallowed_strings = 0,
.additional_len = 1
};
int rval = 1;
const char *iptr;
grub_size_t dollar_cnt = 0;
for (iptr = orig_str; *iptr; iptr++)
if (*iptr == '$')
dollar_cnt++;
ctx.allowed_strings = grub_calloc (dollar_cnt, sizeof (ctx.allowed_strings[0]));
if (parse_string (orig_str, gettext_save_allow, &ctx, 0))
goto fail;
template = _(orig_str);
if (parse_string (template, gettext_getlen, &ctx, 0))
goto fail;
res = grub_malloc (grub_strlen (template) + ctx.additional_len);
if (!res)
goto fail;
if (parse_string (template, gettext_putvar, &ctx, res))
goto fail;
char *escaped = 0;
escaped = wildcard_escape (res);
if (grub_script_argv_append (result, escaped, grub_strlen (escaped)))
{
grub_free (escaped);
goto fail;
}
grub_free (escaped);
rval = 0;
fail:
grub_free (res);
{
grub_size_t i;
for (i = 0; i < ctx.nallowed_strings; i++)
grub_free (ctx.allowed_strings[i]);
}
grub_free (ctx.allowed_strings);
return rval;
}
static int
append (struct grub_script_argv *result,
const char *s, int escape_type)
{
int r;
char *p = 0;
if (escape_type == 0)
return grub_script_argv_append (result, s, grub_strlen (s));
if (escape_type > 0)
p = wildcard_escape (s);
else if (escape_type < 0)
p = wildcard_unescape (s);
if (! p)
return 1;
r = grub_script_argv_append (result, p, grub_strlen (p));
grub_free (p);
return r;
}
/* Convert arguments in ARGLIST into ARGV form. */
static int
grub_script_arglist_to_argv (struct grub_script_arglist *arglist,
struct grub_script_argv *argv)
{
int i;
char **values = 0;
struct grub_script_arg *arg = 0;
struct grub_script_argv result = { 0, 0, 0 };
for (; arglist && arglist->arg; arglist = arglist->next)
{
if (grub_script_argv_next (&result))
goto fail;
arg = arglist->arg;
while (arg)
{
switch (arg->type)
{
case GRUB_SCRIPT_ARG_TYPE_VAR:
case GRUB_SCRIPT_ARG_TYPE_DQVAR:
{
int need_cleanup = 0;
values = grub_script_env_get (arg->str, arg->type);
for (i = 0; values && values[i]; i++)
{
if (!need_cleanup)
{
if (i != 0 && grub_script_argv_next (&result))
{
need_cleanup = 1;
goto cleanup;
}
if (arg->type == GRUB_SCRIPT_ARG_TYPE_VAR)
{
int len;
char ch;
char *p;
char *op;
const char *s = values[i];
len = grub_strlen (values[i]);
/* \? -> \\\? */
/* \* -> \\\* */
/* \ -> \\ */
p = grub_malloc (len * 2 + 1);
if (! p)
{
need_cleanup = 1;
goto cleanup;
}
op = p;
while ((ch = *s++))
{
if (ch == '\\')
{
*op++ = '\\';
if (*s == '?' || *s == '*')
*op++ = '\\';
}
*op++ = ch;
}
*op = '\0';
need_cleanup = grub_script_argv_append (&result, p, op - p);
grub_free (p);
/* Fall through to cleanup */
}
else
{
need_cleanup = append (&result, values[i], 1);
/* Fall through to cleanup */
}
}
cleanup:
grub_free (values[i]);
}
grub_free (values);
if (need_cleanup)
goto fail;
break;
}
case GRUB_SCRIPT_ARG_TYPE_BLOCK:
{
char *p;
if (grub_script_argv_append (&result, "{", 1))
goto fail;
p = wildcard_escape (arg->str);
if (!p)
goto fail;
if (grub_script_argv_append (&result, p,
grub_strlen (p)))
{
grub_free (p);
goto fail;
}
grub_free (p);
if (grub_script_argv_append (&result, "}", 1))
goto fail;
}
result.script = arg->script;
break;
case GRUB_SCRIPT_ARG_TYPE_TEXT:
if (arg->str[0] &&
grub_script_argv_append (&result, arg->str,
grub_strlen (arg->str)))
goto fail;
break;
case GRUB_SCRIPT_ARG_TYPE_GETTEXT:
{
if (gettext_append (&result, arg->str))
goto fail;
}
break;
case GRUB_SCRIPT_ARG_TYPE_DQSTR:
case GRUB_SCRIPT_ARG_TYPE_SQSTR:
if (append (&result, arg->str, 1))
goto fail;
break;
}
arg = arg->next;
}
}
if (! result.args[result.argc - 1])
result.argc--;
/* Perform wildcard expansion. */
int j;
int failed = 0;
struct grub_script_argv unexpanded = result;
result.argc = 0;
result.args = 0;
for (i = 0; unexpanded.args[i]; i++)
{
char **expansions = 0;
if (grub_wildcard_translator
&& grub_wildcard_translator->expand (unexpanded.args[i],
&expansions))
{
grub_script_argv_free (&unexpanded);
goto fail;
}
if (! expansions)
{
grub_script_argv_next (&result);
append (&result, unexpanded.args[i], -1);
}
else
{
for (j = 0; expansions[j]; j++)
{
failed = (failed || grub_script_argv_next (&result) ||
append (&result, expansions[j], 0));
grub_free (expansions[j]);
}
grub_free (expansions);
if (failed)
{
grub_script_argv_free (&unexpanded);
goto fail;
}
}
}
grub_script_argv_free (&unexpanded);
*argv = result;
return 0;
fail:
grub_script_argv_free (&result);
return 1;
}
static grub_err_t
grub_script_execute_cmd (struct grub_script_cmd *cmd)
{
int ret;
char errnobuf[ERRNO_DIGITS_MAX + 1];
if (cmd == 0)
return 0;
ret = cmd->exec (cmd);
grub_snprintf (errnobuf, sizeof (errnobuf), "%d", ret);
grub_env_set ("?", errnobuf);
return ret;
}
/* Execute a function call. */
grub_err_t
grub_script_function_call (grub_script_function_t func, int argc, char **args)
{
grub_err_t ret = 0;
unsigned long loops = active_loops;
struct grub_script_scope *old_scope;
struct grub_script_scope new_scope;
active_loops = 0;
new_scope.flags = 0;
new_scope.shifts = 0;
new_scope.argv.argc = argc;
new_scope.argv.args = args;
old_scope = scope;
scope = &new_scope;
func->executing++;
ret = grub_script_execute (func->func);
func->executing--;
function_return = 0;
active_loops = loops;
replace_scope (old_scope); /* free any scopes by setparams */
return ret;
}
/* Helper for grub_script_execute_sourcecode. */
static grub_err_t
grub_script_execute_sourcecode_getline (char **line,
int cont __attribute__ ((unused)),
void *data)
{
const char **source = data;
const 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;
}
/* Execute a source script. */
grub_err_t
grub_script_execute_sourcecode (const char *source)
{
grub_err_t ret = 0;
struct grub_script *parsed_script;
while (source)
{
char *line;
grub_script_execute_sourcecode_getline (&line, 0, &source);
parsed_script = grub_script_parse
(line, grub_script_execute_sourcecode_getline, &source);
if (! parsed_script)
{
ret = grub_errno;
grub_free (line);
break;
}
ret = grub_script_execute (parsed_script);
grub_script_free (parsed_script);
grub_free (line);
}
return ret;
}
/* Execute a source script in new scope. */
grub_err_t
grub_script_execute_new_scope (const char *source, int argc, char **args)
{
grub_err_t ret = 0;
struct grub_script_scope new_scope;
struct grub_script_scope *old_scope;
new_scope.argv.argc = argc;
new_scope.argv.args = args;
new_scope.flags = 0;
old_scope = scope;
scope = &new_scope;
ret = grub_script_execute_sourcecode (source);
scope = old_scope;
return ret;
}
/* Execute a single command line. */
grub_err_t
grub_script_execute_cmdline (struct grub_script_cmd *cmd)
{
struct grub_script_cmdline *cmdline = (struct grub_script_cmdline *) cmd;
grub_command_t grubcmd;
grub_err_t ret = 0;
grub_script_function_t func = 0;
char errnobuf[18];
char *cmdname, *cmdstring;
int argc, offset = 0, cmdlen = 0;
unsigned int i;
char **args;
int invert;
struct grub_script_argv argv = { 0, 0, 0 };
/* Lookup the command. */
if (grub_script_arglist_to_argv (cmdline->arglist, &argv) || ! argv.args[0])
return grub_errno;
for (i = 0; i < argv.argc; i++)
{
cmdlen += grub_strlen (argv.args[i]) + 1;
}
cmdstring = grub_malloc (cmdlen);
if (!cmdstring)
{
return grub_error (GRUB_ERR_OUT_OF_MEMORY,
N_("cannot allocate command buffer"));
}
for (i = 0; i < argv.argc; i++)
{
offset += grub_snprintf (cmdstring + offset, cmdlen - offset, "%s ",
argv.args[i]);
}
cmdstring[cmdlen - 1] = '\0';
grub_verify_string (cmdstring, GRUB_VERIFY_COMMAND);
grub_free (cmdstring);
invert = 0;
argc = argv.argc - 1;
args = argv.args + 1;
cmdname = argv.args[0];
if (grub_strcmp (cmdname, "!") == 0)
{
if (argv.argc < 2 || ! argv.args[1])
{
grub_script_argv_free (&argv);
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("no command is specified"));
}
invert = 1;
argc = argv.argc - 2;
args = argv.args + 2;
cmdname = argv.args[1];
}
grubcmd = grub_command_find (cmdname);
if (! grubcmd)
{
grub_errno = GRUB_ERR_NONE;
/* It's not a GRUB command, try all functions. */
func = grub_script_function_find (cmdname);
if (! func)
{
/* As a last resort, try if it is an assignment. */
char *assign = grub_strdup (cmdname);
char *eq = grub_strchr (assign, '=');
if (eq)
{
/* This was set because the command was not found. */
grub_errno = GRUB_ERR_NONE;
/* Create two strings and set the variable. */
*eq = '\0';
eq++;
grub_script_env_set (assign, eq);
}
grub_free (assign);
grub_snprintf (errnobuf, sizeof (errnobuf), "%d", grub_errno);
grub_script_env_set ("?", errnobuf);
grub_script_argv_free (&argv);
grub_print_error ();
return 0;
}
}
/* Execute the GRUB command or function. */
if (grubcmd)
{
if (grub_extractor_level && !(grubcmd->flags
& GRUB_COMMAND_FLAG_EXTRACTOR))
ret = grub_error (GRUB_ERR_EXTRACTOR,
"%s isn't allowed to execute in an extractor",
cmdname);
else if ((grubcmd->flags & GRUB_COMMAND_FLAG_BLOCKS) &&
(grubcmd->flags & GRUB_COMMAND_FLAG_EXTCMD))
ret = grub_extcmd_dispatcher (grubcmd, argc, args, argv.script);
else
ret = (grubcmd->func) (grubcmd, argc, args);
}
else
ret = grub_script_function_call (func, argc, args);
if (invert)
{
if (ret == GRUB_ERR_TEST_FAILURE)
grub_errno = ret = GRUB_ERR_NONE;
else if (ret == GRUB_ERR_NONE)
ret = grub_error (GRUB_ERR_TEST_FAILURE, N_("false"));
else
{
grub_print_error ();
ret = GRUB_ERR_NONE;
}
}
/* Free arguments. */
grub_script_argv_free (&argv);
if (grub_errno == GRUB_ERR_TEST_FAILURE)
grub_errno = GRUB_ERR_NONE;
grub_print_error ();
grub_snprintf (errnobuf, sizeof (errnobuf), "%d", ret);
grub_env_set ("?", errnobuf);
return ret;
}
/* Execute a block of one or more commands. */
grub_err_t
grub_script_execute_cmdlist (struct grub_script_cmd *list)
{
int ret = 0;
struct grub_script_cmd *cmd;
/* Loop over every command and execute it. */
for (cmd = list->next; cmd; cmd = cmd->next)
{
if (active_breaks)
break;
ret = grub_script_execute_cmd (cmd);
if (function_return)
break;
}
return ret;
}
/* Execute an if statement. */
grub_err_t
grub_script_execute_cmdif (struct grub_script_cmd *cmd)
{
int ret;
const char *result;
struct grub_script_cmdif *cmdif = (struct grub_script_cmdif *) cmd;
/* Check if the commands results in a true or a false. The value is
read from the env variable `?'. */
ret = grub_script_execute_cmd (cmdif->exec_to_evaluate);
if (function_return)
return ret;
result = grub_env_get ("?");
grub_errno = GRUB_ERR_NONE;
/* Execute the `if' or the `else' part depending on the value of
`?'. */
if (result && ! grub_strcmp (result, "0"))
return grub_script_execute_cmd (cmdif->exec_on_true);
else
return grub_script_execute_cmd (cmdif->exec_on_false);
}
/* Execute a for statement. */
grub_err_t
grub_script_execute_cmdfor (struct grub_script_cmd *cmd)
{
unsigned i;
grub_err_t result;
struct grub_script_argv argv = { 0, 0, 0 };
struct grub_script_cmdfor *cmdfor = (struct grub_script_cmdfor *) cmd;
if (grub_script_arglist_to_argv (cmdfor->words, &argv))
return grub_errno;
active_loops++;
result = 0;
for (i = 0; i < argv.argc; i++)
{
if (is_continue && active_breaks == 1)
active_breaks = 0;
if (! active_breaks)
{
grub_script_env_set (cmdfor->name->str, argv.args[i]);
result = grub_script_execute_cmd (cmdfor->list);
if (function_return)
break;
}
}
if (active_breaks)
active_breaks--;
active_loops--;
grub_script_argv_free (&argv);
return result;
}
/* Execute a "while" or "until" command. */
grub_err_t
grub_script_execute_cmdwhile (struct grub_script_cmd *cmd)
{
int result;
struct grub_script_cmdwhile *cmdwhile = (struct grub_script_cmdwhile *) cmd;
active_loops++;
do {
result = grub_script_execute_cmd (cmdwhile->cond);
if (function_return)
break;
if (cmdwhile->until ? !result : result)
break;
result = grub_script_execute_cmd (cmdwhile->list);
if (function_return)
break;
if (active_breaks == 1 && is_continue)
active_breaks = 0;
if (active_breaks)
break;
} while (1); /* XXX Put a check for ^C here */
if (active_breaks)
active_breaks--;
active_loops--;
return result;
}
/* Execute any GRUB pre-parsed command or script. */
grub_err_t
grub_script_execute (struct grub_script *script)
{
if (script == 0)
return 0;
return grub_script_execute_cmd (script->cmd);
}
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