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-rw-r--r--grub-core/commands/loadenv.c470
1 files changed, 470 insertions, 0 deletions
diff --git a/grub-core/commands/loadenv.c b/grub-core/commands/loadenv.c
new file mode 100644
index 0000000..3fd664a
--- /dev/null
+++ b/grub-core/commands/loadenv.c
@@ -0,0 +1,470 @@
+/* loadenv.c - command to load/save environment variable. */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 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/dl.h>
+#include <grub/mm.h>
+#include <grub/file.h>
+#include <grub/disk.h>
+#include <grub/misc.h>
+#include <grub/env.h>
+#include <grub/partition.h>
+#include <grub/lib/envblk.h>
+#include <grub/extcmd.h>
+#include <grub/i18n.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static const struct grub_arg_option options[] =
+ {
+ /* TRANSLATORS: This option is used to override default filename
+ for loading and storing environment. */
+ {"file", 'f', 0, N_("Specify filename."), 0, ARG_TYPE_PATHNAME},
+ {"skip-sig", 's', 0,
+ N_("Skip signature-checking of the environment file."), 0, ARG_TYPE_NONE},
+ {0, 0, 0, 0, 0, 0}
+ };
+
+/* Opens 'filename' with compression filters disabled. Optionally disables the
+ PUBKEY filter (that insists upon properly signed files) as well. PUBKEY
+ filter is restored before the function returns. */
+static grub_file_t
+open_envblk_file (char *filename,
+ enum grub_file_type type)
+{
+ grub_file_t file;
+ char *buf = 0;
+
+ if (! filename)
+ {
+ const char *prefix;
+ int len;
+
+ prefix = grub_env_get ("prefix");
+ if (! prefix)
+ {
+ grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("variable `%s' isn't set"), "prefix");
+ return 0;
+ }
+
+ len = grub_strlen (prefix);
+ buf = grub_malloc (len + 1 + sizeof (GRUB_ENVBLK_DEFCFG));
+ if (! buf)
+ return 0;
+ filename = buf;
+
+ grub_strcpy (filename, prefix);
+ filename[len] = '/';
+ grub_strcpy (filename + len + 1, GRUB_ENVBLK_DEFCFG);
+ }
+
+ file = grub_file_open (filename, type);
+
+ grub_free (buf);
+ return file;
+}
+
+static grub_envblk_t
+read_envblk_file (grub_file_t file)
+{
+ grub_off_t offset = 0;
+ char *buf;
+ grub_size_t size = grub_file_size (file);
+ grub_envblk_t envblk;
+
+ buf = grub_malloc (size);
+ if (! buf)
+ return 0;
+
+ while (size > 0)
+ {
+ grub_ssize_t ret;
+
+ ret = grub_file_read (file, buf + offset, size);
+ if (ret <= 0)
+ {
+ grub_free (buf);
+ return 0;
+ }
+
+ size -= ret;
+ offset += ret;
+ }
+
+ envblk = grub_envblk_open (buf, offset);
+ if (! envblk)
+ {
+ grub_free (buf);
+ grub_error (GRUB_ERR_BAD_FILE_TYPE, "invalid environment block");
+ return 0;
+ }
+
+ return envblk;
+}
+
+struct grub_env_whitelist
+{
+ grub_size_t len;
+ char **list;
+};
+typedef struct grub_env_whitelist grub_env_whitelist_t;
+
+static int
+test_whitelist_membership (const char* name,
+ const grub_env_whitelist_t* whitelist)
+{
+ grub_size_t i;
+
+ for (i = 0; i < whitelist->len; i++)
+ if (grub_strcmp (name, whitelist->list[i]) == 0)
+ return 1; /* found it */
+
+ return 0; /* not found */
+}
+
+/* Helper for grub_cmd_load_env. */
+static int
+set_var (const char *name, const char *value, void *whitelist)
+{
+ if (! whitelist)
+ {
+ grub_env_set (name, value);
+ return 0;
+ }
+
+ if (test_whitelist_membership (name,
+ (const grub_env_whitelist_t *) whitelist))
+ grub_env_set (name, value);
+
+ return 0;
+}
+
+static grub_err_t
+grub_cmd_load_env (grub_extcmd_context_t ctxt, int argc, char **args)
+{
+ struct grub_arg_list *state = ctxt->state;
+ grub_file_t file;
+ grub_envblk_t envblk;
+ grub_env_whitelist_t whitelist;
+
+ whitelist.len = argc;
+ whitelist.list = args;
+
+ /* state[0] is the -f flag; state[1] is the --skip-sig flag */
+ file = open_envblk_file ((state[0].set) ? state[0].arg : 0,
+ GRUB_FILE_TYPE_LOADENV
+ | (state[1].set
+ ? GRUB_FILE_TYPE_SKIP_SIGNATURE : GRUB_FILE_TYPE_NONE));
+ if (! file)
+ return grub_errno;
+
+ envblk = read_envblk_file (file);
+ if (! envblk)
+ goto fail;
+
+ /* argc > 0 indicates caller provided a whitelist of variables to read. */
+ grub_envblk_iterate (envblk, argc > 0 ? &whitelist : 0, set_var);
+ grub_envblk_close (envblk);
+
+ fail:
+ grub_file_close (file);
+ return grub_errno;
+}
+
+/* Print all variables in current context. */
+static int
+print_var (const char *name, const char *value,
+ void *hook_data __attribute__ ((unused)))
+{
+ grub_printf ("%s=%s\n", name, value);
+ return 0;
+}
+
+static grub_err_t
+grub_cmd_list_env (grub_extcmd_context_t ctxt,
+ int argc __attribute__ ((unused)),
+ char **args __attribute__ ((unused)))
+{
+ struct grub_arg_list *state = ctxt->state;
+ grub_file_t file;
+ grub_envblk_t envblk;
+
+ file = open_envblk_file ((state[0].set) ? state[0].arg : 0,
+ GRUB_FILE_TYPE_LOADENV
+ | (state[1].set
+ ? GRUB_FILE_TYPE_SKIP_SIGNATURE : GRUB_FILE_TYPE_NONE));
+ if (! file)
+ return grub_errno;
+
+ envblk = read_envblk_file (file);
+ if (! envblk)
+ goto fail;
+
+ grub_envblk_iterate (envblk, NULL, print_var);
+ grub_envblk_close (envblk);
+
+ fail:
+ grub_file_close (file);
+ return grub_errno;
+}
+
+/* Used to maintain a variable length of blocklists internally. */
+struct blocklist
+{
+ grub_disk_addr_t sector;
+ unsigned offset;
+ unsigned length;
+ struct blocklist *next;
+};
+
+static void
+free_blocklists (struct blocklist *p)
+{
+ struct blocklist *q;
+
+ for (; p; p = q)
+ {
+ q = p->next;
+ grub_free (p);
+ }
+}
+
+static grub_err_t
+check_blocklists (grub_envblk_t envblk, struct blocklist *blocklists,
+ grub_file_t file)
+{
+ grub_size_t total_length;
+ grub_size_t index;
+ grub_disk_t disk;
+ grub_disk_addr_t part_start;
+ struct blocklist *p;
+ char *buf;
+
+ /* Sanity checks. */
+ total_length = 0;
+ for (p = blocklists; p; p = p->next)
+ {
+ struct blocklist *q;
+ /* Check if any pair of blocks overlap. */
+ for (q = p->next; q; q = q->next)
+ {
+ grub_disk_addr_t s1, s2;
+ grub_disk_addr_t e1, e2;
+
+ s1 = p->sector;
+ e1 = s1 + ((p->length + GRUB_DISK_SECTOR_SIZE - 1) >> GRUB_DISK_SECTOR_BITS);
+
+ s2 = q->sector;
+ e2 = s2 + ((q->length + GRUB_DISK_SECTOR_SIZE - 1) >> GRUB_DISK_SECTOR_BITS);
+
+ if (s1 < e2 && s2 < e1)
+ {
+ /* This might be actually valid, but it is unbelievable that
+ any filesystem makes such a silly allocation. */
+ return grub_error (GRUB_ERR_BAD_FS, "malformed file");
+ }
+ }
+
+ total_length += p->length;
+ }
+
+ if (total_length != grub_file_size (file))
+ {
+ /* Maybe sparse, unallocated sectors. No way in GRUB. */
+ return grub_error (GRUB_ERR_BAD_FILE_TYPE, "sparse file not allowed");
+ }
+
+ /* One more sanity check. Re-read all sectors by blocklists, and compare
+ those with the data read via a file. */
+ disk = file->device->disk;
+
+ part_start = grub_partition_get_start (disk->partition);
+
+ buf = grub_envblk_buffer (envblk);
+ char *blockbuf = NULL;
+ grub_size_t blockbuf_len = 0;
+ for (p = blocklists, index = 0; p; index += p->length, p = p->next)
+ {
+ if (p->length > blockbuf_len)
+ {
+ grub_free (blockbuf);
+ blockbuf_len = 2 * p->length;
+ blockbuf = grub_malloc (blockbuf_len);
+ if (!blockbuf)
+ return grub_errno;
+ }
+
+ if (grub_disk_read (disk, p->sector - part_start,
+ p->offset, p->length, blockbuf))
+ return grub_errno;
+
+ if (grub_memcmp (buf + index, blockbuf, p->length) != 0)
+ return grub_error (GRUB_ERR_FILE_READ_ERROR, "invalid blocklist");
+ }
+
+ return GRUB_ERR_NONE;
+}
+
+static int
+write_blocklists (grub_envblk_t envblk, struct blocklist *blocklists,
+ grub_file_t file)
+{
+ char *buf;
+ grub_disk_t disk;
+ grub_disk_addr_t part_start;
+ struct blocklist *p;
+ grub_size_t index;
+
+ buf = grub_envblk_buffer (envblk);
+ disk = file->device->disk;
+ part_start = grub_partition_get_start (disk->partition);
+
+ index = 0;
+ for (p = blocklists; p; index += p->length, p = p->next)
+ {
+ if (grub_disk_write (disk, p->sector - part_start,
+ p->offset, p->length, buf + index))
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Context for grub_cmd_save_env. */
+struct grub_cmd_save_env_ctx
+{
+ struct blocklist *head, *tail;
+};
+
+/* Store blocklists in a linked list. */
+static void
+save_env_read_hook (grub_disk_addr_t sector, unsigned offset, unsigned length,
+ void *data)
+{
+ struct grub_cmd_save_env_ctx *ctx = data;
+ struct blocklist *block;
+
+ block = grub_malloc (sizeof (*block));
+ if (! block)
+ return;
+
+ block->sector = sector;
+ block->offset = offset;
+ block->length = length;
+
+ /* Slightly complicated, because the list should be FIFO. */
+ block->next = 0;
+ if (ctx->tail)
+ ctx->tail->next = block;
+ ctx->tail = block;
+ if (! ctx->head)
+ ctx->head = block;
+}
+
+static grub_err_t
+grub_cmd_save_env (grub_extcmd_context_t ctxt, int argc, char **args)
+{
+ struct grub_arg_list *state = ctxt->state;
+ grub_file_t file;
+ grub_envblk_t envblk;
+ struct grub_cmd_save_env_ctx ctx = {
+ .head = 0,
+ .tail = 0
+ };
+
+ if (! argc)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, "no variable is specified");
+
+ file = open_envblk_file ((state[0].set) ? state[0].arg : 0,
+ GRUB_FILE_TYPE_SAVEENV
+ | GRUB_FILE_TYPE_SKIP_SIGNATURE);
+ if (! file)
+ return grub_errno;
+
+ if (! file->device->disk)
+ {
+ grub_file_close (file);
+ return grub_error (GRUB_ERR_BAD_DEVICE, "disk device required");
+ }
+
+ file->read_hook = save_env_read_hook;
+ file->read_hook_data = &ctx;
+ envblk = read_envblk_file (file);
+ file->read_hook = 0;
+ if (! envblk)
+ goto fail;
+
+ if (check_blocklists (envblk, ctx.head, file))
+ goto fail;
+
+ while (argc)
+ {
+ const char *value;
+
+ value = grub_env_get (args[0]);
+ if (value)
+ {
+ if (! grub_envblk_set (envblk, args[0], value))
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, "environment block too small");
+ goto fail;
+ }
+ }
+ else
+ grub_envblk_delete (envblk, args[0]);
+
+ argc--;
+ args++;
+ }
+
+ write_blocklists (envblk, ctx.head, file);
+
+ fail:
+ if (envblk)
+ grub_envblk_close (envblk);
+ free_blocklists (ctx.head);
+ grub_file_close (file);
+ return grub_errno;
+}
+
+static grub_extcmd_t cmd_load, cmd_list, cmd_save;
+
+GRUB_MOD_INIT(loadenv)
+{
+ cmd_load =
+ grub_register_extcmd ("load_env", grub_cmd_load_env, 0,
+ N_("[-f FILE] [-s|--skip-sig] [variable_name_to_whitelist] [...]"),
+ N_("Load variables from environment block file."),
+ options);
+ cmd_list =
+ grub_register_extcmd ("list_env", grub_cmd_list_env, 0, N_("[-f FILE]"),
+ N_("List variables from environment block file."),
+ options);
+ cmd_save =
+ grub_register_extcmd ("save_env", grub_cmd_save_env, 0,
+ N_("[-f FILE] variable_name [...]"),
+ N_("Save variables to environment block file."),
+ options);
+}
+
+GRUB_MOD_FINI(loadenv)
+{
+ grub_unregister_extcmd (cmd_load);
+ grub_unregister_extcmd (cmd_list);
+ grub_unregister_extcmd (cmd_save);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 17:54:11 +0000