grub/kern/env.c
okuji 5f968e1e61 2005-07-20 Yoshinori K. Okuji <okuji@enbug.org>
Change the semantics of variable hooks. They now return	strings
	instead of error values.

	* util/i386/pc/grub-setup.c: Include grub/env.h.
	(setup): Use grub_device_set_root instead of grub_env_set.

	* kern/rescue.c (grub_rescue_cmd_root): Use grub_env_set and
	grub_env_get instead of grub_device_set_root and
	grub_device_get_root, respectively.

	* kern/main.c (grub_env_write_root): New function.
	(grub_set_root_dev): Register grub_env_write_hook for "root". Use
	grub_env_set instead of grub_device_set_root.

	* kern/env.c (HASHSZ): Reduced to 13, because GRUB does not need
	many variables.
	(grub_env_set): Set ENV->VALUE to the result of ENV->WRITE_HOOK
	rather than calling ENV->WRITE_HOOK afterwards.
	(grub_env_get): Return the result of ENV->READ_HOOK rather than
	passing a pointer of a pointer.
	(grub_register_variable_hook): Change the types of "read_hook" and
	"write_hook" to grub_env_read_hook_t and grub_env_write_hook_t,
	respectively.
	Allocate the default empty string on the heap, because this string
	may be freed later.

	* kern/device.c: Include grub/env.h.
	(grub_device_set_root): Removed.
	(grub_device_get_root): Likewise.
	(grub_device_open): Use grub_env_get instead of
	grub_device_get_root.

	* include/grub/env.h (grub_env_read_hook_t): New type.
	(grub_env_write_hook_t): Likewise.
	(grub_env_var): Change the types of "read_hook" and "write_hook"
	to grub_env_read_hook_t and grub_env_write_hook_t, respectively.
	(grub_register_variable_hook): Likewise.

	* include/grub/device.h (grub_device_set_root): Removed.
	(grub_device_set_root): Likewise.

	* fs/fat.c (grub_fat_dir): Make a copy of PATH in DIRNAME, and
	make sure that DIRNAME terminates with '/', so that
	grub_fat_find_dir will fail if PATH is not a directory.

	* commands/ls.c (grub_ls_list_files): Remove the qualifier const
	from DIRNAME.
	Use the qualifier auto for print_files and print_files_long.
	If FS->DIR sets GRUB_ERRNO to GRUB_ERR_BAD_FILE_TYPE, try DIRNAME
	as a regular file.
	Put a newline only if there is no error.
	(grub_cmd_ls): Remove grub_ls_print_files, because this is not
	used.
2005-07-20 20:30:46 +00:00

213 lines
4.6 KiB
C

/* env.c - Environment variables */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2005 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 2 of the License, or
* (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/env.h>
#include <grub/misc.h>
#include <grub/mm.h>
/* The size of the hash table. */
#define HASHSZ 13
/* A hashtable for quick lookup of variables. */
static struct grub_env_var *grub_env[HASHSZ];
/* The variables in a sorted list. */
static struct grub_env_var *grub_env_sorted;
/* Return the hash representation of the string S. */
static unsigned int grub_env_hashval (const char *s)
{
unsigned int i = 0;
/* XXX: This can be done much more effecient. */
while (*s)
i += 5 * *(s++);
return i % HASHSZ;
}
static struct grub_env_var *
grub_env_find (const char *name)
{
struct grub_env_var *var;
int idx = grub_env_hashval (name);
for (var = grub_env[idx]; var; var = var->next)
if (! grub_strcmp (var->name, name))
return var;
return 0;
}
grub_err_t
grub_env_set (const char *var, const char *val)
{
int idx = grub_env_hashval (var);
struct grub_env_var *env;
struct grub_env_var *sort;
struct grub_env_var **sortp;
/* If the variable does already exist, just update the variable. */
env = grub_env_find (var);
if (env)
{
char *old = env->value;
if (env->write_hook)
env->value = env->write_hook (env, val);
else
env->value = grub_strdup (val);
if (! env->value)
{
env->value = old;
return grub_errno;
}
grub_free (old);
return 0;
}
/* The variable does not exist, create it. */
env = grub_malloc (sizeof (struct grub_env_var));
if (! env)
return grub_errno;
grub_memset (env, 0, sizeof (struct grub_env_var));
env->name = grub_strdup (var);
if (! env->name)
goto fail;
env->value = grub_strdup (val);
if (! env->name)
goto fail;
/* Insert it in the hashtable. */
env->prevp = &grub_env[idx];
env->next = grub_env[idx];
if (grub_env[idx])
grub_env[idx]->prevp = &env->next;
grub_env[idx] = env;
/* Insert it in the sorted list. */
sortp = &grub_env_sorted;
sort = grub_env_sorted;
while (sort)
{
if (grub_strcmp (sort->name, var) > 0)
break;
sortp = &sort->sort_next;
sort = sort->sort_next;
}
env->sort_prevp = sortp;
env->sort_next = sort;
if (sort)
sort->sort_prevp = &env->sort_next;
*sortp = env;
fail:
if (grub_errno)
{
grub_free (env->name);
grub_free (env->value);
grub_free (env);
}
return 0;
}
char *
grub_env_get (const char *name)
{
struct grub_env_var *env;
env = grub_env_find (name);
if (! env)
return 0;
if (env->read_hook)
return env->read_hook (env, env->value);
return env->value;
}
void
grub_env_unset (const char *name)
{
struct grub_env_var *env;
env = grub_env_find (name);
if (! env)
return;
/* XXX: It is not possible to unset variables with a read or write
hook. */
if (env->read_hook || env->write_hook)
return;
*env->prevp = env->next;
if (env->next)
env->next->prevp = env->prevp;
*env->sort_prevp = env->sort_next;
if (env->sort_next)
env->sort_next->sort_prevp = env->sort_prevp;
grub_free (env->name);
grub_free (env->value);
grub_free (env);
return;
}
void
grub_env_iterate (int (* func) (struct grub_env_var *var))
{
struct grub_env_var *env;
for (env = grub_env_sorted; env; env = env->sort_next)
if (func (env))
return;
}
grub_err_t
grub_register_variable_hook (const char *var,
grub_env_read_hook_t read_hook,
grub_env_write_hook_t write_hook)
{
struct grub_env_var *env = grub_env_find (var);
if (! env)
{
char *val = grub_strdup ("");
if (! val)
return grub_errno;
if (grub_env_set (var, val) != GRUB_ERR_NONE)
return grub_errno;
}
env = grub_env_find (var);
/* XXX Insert an assertion? */
env->read_hook = read_hook;
env->write_hook = write_hook;
return GRUB_ERR_NONE;
}