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/* loadenv.c - command to load/save environment variable. */
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2008,2009,2010 Free Software Foundation, Inc.
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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#include <grub/file.h>
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#include <grub/disk.h>
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#include <grub/misc.h>
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#include <grub/partition.h>
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#include <grub/lib/envblk.h>
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#include <grub/extcmd.h>
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#include <grub/i18n.h>
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static const struct grub_arg_option options[] =
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{"file", 'f', 0, N_("Specify filename."), 0, ARG_TYPE_PATHNAME},
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open_envblk_file (char *filename)
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prefix = grub_env_get ("prefix");
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len = grub_strlen (prefix);
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filename = grub_malloc (len + 1 + sizeof (GRUB_ENVBLK_DEFCFG));
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grub_strcpy (filename, prefix);
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grub_strcpy (filename + len + 1, GRUB_ENVBLK_DEFCFG);
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grub_file_filter_disable_compression ();
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file = grub_file_open (filename);
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grub_error (GRUB_ERR_FILE_NOT_FOUND, "prefix is not found");
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grub_file_filter_disable_compression ();
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return grub_file_open (filename);
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read_envblk_file (grub_file_t file)
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grub_off_t offset = 0;
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grub_size_t size = grub_file_size (file);
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buf = grub_malloc (size);
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ret = grub_file_read (file, buf + offset, size);
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if (grub_errno == GRUB_ERR_NONE)
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grub_error (GRUB_ERR_FILE_READ_ERROR, "cannot read");
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envblk = grub_envblk_open (buf, offset);
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grub_error (GRUB_ERR_BAD_FILE_TYPE, "invalid environment block");
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grub_cmd_load_env (grub_extcmd_context_t ctxt,
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int argc __attribute__ ((unused)),
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char **args __attribute__ ((unused)))
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struct grub_arg_list *state = ctxt->state;
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grub_envblk_t envblk;
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auto int set_var (const char *name, const char *value);
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int set_var (const char *name, const char *value)
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grub_env_set (name, value);
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file = open_envblk_file ((state[0].set) ? state[0].arg : 0);
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envblk = read_envblk_file (file);
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grub_envblk_iterate (envblk, set_var);
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grub_envblk_close (envblk);
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grub_file_close (file);
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grub_cmd_list_env (grub_extcmd_context_t ctxt,
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int argc __attribute__ ((unused)),
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char **args __attribute__ ((unused)))
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struct grub_arg_list *state = ctxt->state;
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grub_envblk_t envblk;
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/* Print all variables in current context. */
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auto int print_var (const char *name, const char *value);
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int print_var (const char *name, const char *value)
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grub_printf ("%s=%s\n", name, value);
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file = open_envblk_file ((state[0].set) ? state[0].arg : 0);
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envblk = read_envblk_file (file);
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grub_envblk_iterate (envblk, print_var);
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grub_envblk_close (envblk);
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grub_file_close (file);
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/* Used to maintain a variable length of blocklists internally. */
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grub_disk_addr_t sector;
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struct blocklist *next;
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free_blocklists (struct blocklist *p)
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check_blocklists (grub_envblk_t envblk, struct blocklist *blocklists,
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grub_size_t total_length;
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grub_disk_addr_t part_start;
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for (p = blocklists; p; p = p->next)
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for (q = p->next; q; q = q->next)
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/* Check if any pair of blocks overlap. */
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if (p->sector == q->sector)
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/* This might be actually valid, but it is unbelievable that
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any filesystem makes such a silly allocation. */
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return grub_error (GRUB_ERR_BAD_FS, "malformed file");
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total_length += p->length;
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if (total_length != grub_file_size (file))
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/* Maybe sparse, unallocated sectors. No way in GRUB. */
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, "sparse file not allowed");
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/* One more sanity check. Re-read all sectors by blocklists, and compare
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those with the data read via a file. */
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disk = file->device->disk;
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part_start = grub_partition_get_start (disk->partition);
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buf = grub_envblk_buffer (envblk);
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for (p = blocklists, index = 0; p; index += p->length, p = p->next)
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char blockbuf[GRUB_DISK_SECTOR_SIZE];
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if (grub_disk_read (disk, p->sector - part_start,
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p->offset, p->length, blockbuf))
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if (grub_memcmp (buf + index, blockbuf, p->length) != 0)
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return grub_error (GRUB_ERR_FILE_READ_ERROR, "invalid blocklist");
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return GRUB_ERR_NONE;
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write_blocklists (grub_envblk_t envblk, struct blocklist *blocklists,
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grub_disk_addr_t part_start;
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buf = grub_envblk_buffer (envblk);
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disk = file->device->disk;
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part_start = grub_partition_get_start (disk->partition);
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for (p = blocklists; p; index += p->length, p = p->next)
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if (grub_disk_write (disk, p->sector - part_start,
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p->offset, p->length, buf + index))
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grub_cmd_save_env (grub_extcmd_context_t ctxt, int argc, char **args)
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struct grub_arg_list *state = ctxt->state;
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grub_envblk_t envblk;
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struct blocklist *head = 0;
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struct blocklist *tail = 0;
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/* Store blocklists in a linked list. */
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auto void NESTED_FUNC_ATTR read_hook (grub_disk_addr_t sector,
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void NESTED_FUNC_ATTR read_hook (grub_disk_addr_t sector,
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unsigned offset, unsigned length)
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struct blocklist *block;
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if (offset + length > GRUB_DISK_SECTOR_SIZE)
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/* Seemingly a bug. */
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block = grub_malloc (sizeof (*block));
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block->sector = sector;
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block->offset = offset;
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block->length = length;
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/* Slightly complicated, because the list should be FIFO. */
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "no variable is specified");
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file = open_envblk_file ((state[0].set) ? state[0].arg : 0);
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if (! file->device->disk)
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grub_file_close (file);
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return grub_error (GRUB_ERR_BAD_DEVICE, "disk device required");
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file->read_hook = read_hook;
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envblk = read_envblk_file (file);
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if (check_blocklists (envblk, head, file))
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value = grub_env_get (args[0]);
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if (! grub_envblk_set (envblk, args[0], value))
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grub_error (GRUB_ERR_BAD_ARGUMENT, "environment block too small");
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write_blocklists (envblk, head, file);
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grub_envblk_close (envblk);
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free_blocklists (head);
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grub_file_close (file);
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static grub_extcmd_t cmd_load, cmd_list, cmd_save;
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GRUB_MOD_INIT(loadenv)
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grub_register_extcmd ("load_env", grub_cmd_load_env, 0, N_("[-f FILE]"),
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N_("Load variables from environment block file."),
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grub_register_extcmd ("list_env", grub_cmd_list_env, 0, N_("[-f FILE]"),
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N_("List variables from environment block file."),
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grub_register_extcmd ("save_env", grub_cmd_save_env, 0,
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N_("[-f FILE] variable_name [...]"),
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N_("Save variables to environment block file."),
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GRUB_MOD_FINI(loadenv)
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grub_unregister_extcmd (cmd_load);
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grub_unregister_extcmd (cmd_list);
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grub_unregister_extcmd (cmd_save);