mirror of https://github.com/ventoy/Ventoy
1.0.11 release
longpanda
4 years ago
parent
f0d59949e5
commit
ef40780f20
@ -0,0 +1,429 @@
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/* fshelp.c -- Filesystem helper functions */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2004,2005,2006,2007,2008 Free Software Foundation, Inc.
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*
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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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*
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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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*
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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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*/
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#include <grub/err.h>
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#include <grub/mm.h>
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#include <grub/misc.h>
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#include <grub/disk.h>
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#include <grub/fshelp.h>
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#include <grub/dl.h>
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#include <grub/i18n.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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typedef int (*iterate_dir_func) (grub_fshelp_node_t dir,
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grub_fshelp_iterate_dir_hook_t hook,
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void *data);
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typedef grub_err_t (*lookup_file_func) (grub_fshelp_node_t dir,
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const char *name,
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grub_fshelp_node_t *foundnode,
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enum grub_fshelp_filetype *foundtype);
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typedef char *(*read_symlink_func) (grub_fshelp_node_t node);
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struct stack_element {
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struct stack_element *parent;
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grub_fshelp_node_t node;
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enum grub_fshelp_filetype type;
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};
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/* Context for grub_fshelp_find_file. */
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struct grub_fshelp_find_file_ctx
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{
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/* Inputs. */
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const char *path;
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grub_fshelp_node_t rootnode;
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/* Global options. */
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int symlinknest;
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/* Current file being traversed and its parents. */
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struct stack_element *currnode;
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};
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/* Helper for find_file_iter. */
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static void
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free_node (grub_fshelp_node_t node, struct grub_fshelp_find_file_ctx *ctx)
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{
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if (node != ctx->rootnode)
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grub_free (node);
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}
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static void
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pop_element (struct grub_fshelp_find_file_ctx *ctx)
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{
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struct stack_element *el;
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el = ctx->currnode;
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ctx->currnode = el->parent;
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free_node (el->node, ctx);
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grub_free (el);
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}
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static void
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free_stack (struct grub_fshelp_find_file_ctx *ctx)
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{
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while (ctx->currnode)
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pop_element (ctx);
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}
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static void
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go_up_a_level (struct grub_fshelp_find_file_ctx *ctx)
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{
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if (!ctx->currnode->parent)
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return;
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pop_element (ctx);
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}
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static grub_err_t
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push_node (struct grub_fshelp_find_file_ctx *ctx, grub_fshelp_node_t node, enum grub_fshelp_filetype filetype)
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{
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struct stack_element *nst;
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nst = grub_malloc (sizeof (*nst));
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if (!nst)
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return grub_errno;
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nst->node = node;
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nst->type = filetype & ~GRUB_FSHELP_CASE_INSENSITIVE;
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nst->parent = ctx->currnode;
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ctx->currnode = nst;
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return GRUB_ERR_NONE;
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}
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static grub_err_t
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go_to_root (struct grub_fshelp_find_file_ctx *ctx)
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{
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free_stack (ctx);
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return push_node (ctx, ctx->rootnode, GRUB_FSHELP_DIR);
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}
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struct grub_fshelp_find_file_iter_ctx
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{
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const char *name;
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grub_fshelp_node_t *foundnode;
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enum grub_fshelp_filetype *foundtype;
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};
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/* Helper for grub_fshelp_find_file. */
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static int
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find_file_iter (const char *filename, enum grub_fshelp_filetype filetype,
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grub_fshelp_node_t node, void *data)
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{
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struct grub_fshelp_find_file_iter_ctx *ctx = data;
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if (filetype == GRUB_FSHELP_UNKNOWN ||
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((filetype & GRUB_FSHELP_CASE_INSENSITIVE)
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? grub_strcasecmp (ctx->name, filename)
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: grub_strcmp (ctx->name, filename)))
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{
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grub_free (node);
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return 0;
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}
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/* The node is found, stop iterating over the nodes. */
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*ctx->foundnode = node;
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*ctx->foundtype = filetype;
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return 1;
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}
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static grub_err_t
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directory_find_file (grub_fshelp_node_t node, const char *name, grub_fshelp_node_t *foundnode,
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enum grub_fshelp_filetype *foundtype, iterate_dir_func iterate_dir)
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{
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int found;
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struct grub_fshelp_find_file_iter_ctx ctx = {
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.foundnode = foundnode,
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.foundtype = foundtype,
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.name = name
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};
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found = iterate_dir (node, find_file_iter, &ctx);
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if (! found)
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{
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if (grub_errno)
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return grub_errno;
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}
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return GRUB_ERR_NONE;
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}
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static grub_err_t
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find_file (char *currpath,
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iterate_dir_func iterate_dir, lookup_file_func lookup_file,
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read_symlink_func read_symlink,
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struct grub_fshelp_find_file_ctx *ctx)
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{
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char *name, *next;
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grub_err_t err;
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for (name = currpath; ; name = next)
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{
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char c;
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grub_fshelp_node_t foundnode = NULL;
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enum grub_fshelp_filetype foundtype = 0;
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/* Remove all leading slashes. */
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while (*name == '/')
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name++;
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/* Found the node! */
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if (! *name)
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return 0;
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/* Extract the actual part from the pathname. */
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for (next = name; *next && *next != '/'; next++);
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/* At this point it is expected that the current node is a
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directory, check if this is true. */
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if (ctx->currnode->type != GRUB_FSHELP_DIR)
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory"));
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/* Don't rely on fs providing actual . in the listing. */
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if (next - name == 1 && name[0] == '.')
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continue;
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/* Don't rely on fs providing actual .. in the listing. */
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if (next - name == 2 && name[0] == '.' && name[1] == '.')
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{
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go_up_a_level (ctx);
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continue;
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}
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/* Iterate over the directory. */
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c = *next;
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*next = '\0';
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if (lookup_file)
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err = lookup_file (ctx->currnode->node, name, &foundnode, &foundtype);
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else
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err = directory_find_file (ctx->currnode->node, name, &foundnode, &foundtype, iterate_dir);
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*next = c;
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if (err)
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return err;
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if (!foundnode)
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break;
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push_node (ctx, foundnode, foundtype);
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/* Read in the symlink and follow it. */
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if (ctx->currnode->type == GRUB_FSHELP_SYMLINK)
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{
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char *symlink;
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/* Test if the symlink does not loop. */
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if (++ctx->symlinknest == 8)
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return grub_error (GRUB_ERR_SYMLINK_LOOP,
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N_("too deep nesting of symlinks"));
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symlink = read_symlink (ctx->currnode->node);
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if (!symlink)
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return grub_errno;
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/* The symlink is an absolute path, go back to the root inode. */
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if (symlink[0] == '/')
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{
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err = go_to_root (ctx);
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if (err)
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return err;
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}
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else
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{
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/* Get from symlink to containing directory. */
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go_up_a_level (ctx);
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}
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/* Lookup the node the symlink points to. */
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find_file (symlink, iterate_dir, lookup_file, read_symlink, ctx);
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grub_free (symlink);
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if (grub_errno)
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return grub_errno;
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}
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}
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return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("file `%s' not found"),
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ctx->path);
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}
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static grub_err_t
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grub_fshelp_find_file_real (const char *path, grub_fshelp_node_t rootnode,
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grub_fshelp_node_t *foundnode,
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iterate_dir_func iterate_dir,
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lookup_file_func lookup_file,
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read_symlink_func read_symlink,
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enum grub_fshelp_filetype expecttype)
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{
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struct grub_fshelp_find_file_ctx ctx = {
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.path = path,
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.rootnode = rootnode,
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.symlinknest = 0,
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.currnode = 0
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};
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grub_err_t err;
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enum grub_fshelp_filetype foundtype;
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char *duppath;
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if (!path || path[0] != '/')
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{
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return grub_error (GRUB_ERR_BAD_FILENAME, N_("invalid file name `%s'"), path);
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}
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err = go_to_root (&ctx);
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if (err)
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return err;
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duppath = grub_strdup (path);
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if (!duppath)
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return grub_errno;
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err = find_file (duppath, iterate_dir, lookup_file, read_symlink, &ctx);
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grub_free (duppath);
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if (err)
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{
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free_stack (&ctx);
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return err;
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}
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*foundnode = ctx.currnode->node;
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foundtype = ctx.currnode->type;
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/* Avoid the node being freed. */
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ctx.currnode->node = 0;
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free_stack (&ctx);
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/* Check if the node that was found was of the expected type. */
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if (expecttype == GRUB_FSHELP_REG && foundtype != expecttype)
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a regular file"));
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else if (expecttype == GRUB_FSHELP_DIR && foundtype != expecttype)
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory"));
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return 0;
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}
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/* Lookup the node PATH. The node ROOTNODE describes the root of the
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directory tree. The node found is returned in FOUNDNODE, which is
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either a ROOTNODE or a new malloc'ed node. ITERATE_DIR is used to
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iterate over all directory entries in the current node.
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READ_SYMLINK is used to read the symlink if a node is a symlink.
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EXPECTTYPE is the type node that is expected by the called, an
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error is generated if the node is not of the expected type. */
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grub_err_t
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grub_fshelp_find_file (const char *path, grub_fshelp_node_t rootnode,
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grub_fshelp_node_t *foundnode,
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iterate_dir_func iterate_dir,
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read_symlink_func read_symlink,
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enum grub_fshelp_filetype expecttype)
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{
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return grub_fshelp_find_file_real (path, rootnode, foundnode,
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iterate_dir, NULL,
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read_symlink, expecttype);
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}
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grub_err_t
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grub_fshelp_find_file_lookup (const char *path, grub_fshelp_node_t rootnode,
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grub_fshelp_node_t *foundnode,
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lookup_file_func lookup_file,
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read_symlink_func read_symlink,
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enum grub_fshelp_filetype expecttype)
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{
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return grub_fshelp_find_file_real (path, rootnode, foundnode,
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NULL, lookup_file,
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read_symlink, expecttype);
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}
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/* Read LEN bytes from the file NODE on disk DISK into the buffer BUF,
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beginning with the block POS. READ_HOOK should be set before
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reading a block from the file. READ_HOOK_DATA is passed through as
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the DATA argument to READ_HOOK. GET_BLOCK is used to translate
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file blocks to disk blocks. The file is FILESIZE bytes big and the
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blocks have a size of LOG2BLOCKSIZE (in log2). */
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grub_ssize_t
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grub_fshelp_read_file (grub_disk_t disk, grub_fshelp_node_t node,
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grub_disk_read_hook_t read_hook, void *read_hook_data,
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grub_off_t pos, grub_size_t len, char *buf,
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grub_disk_addr_t (*get_block) (grub_fshelp_node_t node,
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grub_disk_addr_t block),
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grub_off_t filesize, int log2blocksize,
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grub_disk_addr_t blocks_start)
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{
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grub_disk_addr_t i, blockcnt;
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int blocksize = 1 << (log2blocksize + GRUB_DISK_SECTOR_BITS);
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if (pos > filesize)
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{
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grub_error (GRUB_ERR_OUT_OF_RANGE,
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N_("attempt to read past the end of file"));
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return -1;
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}
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/* Adjust LEN so it we can't read past the end of the file. */
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if (pos + len > filesize)
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len = filesize - pos;
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blockcnt = ((len + pos) + blocksize - 1) >> (log2blocksize + GRUB_DISK_SECTOR_BITS);
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for (i = pos >> (log2blocksize + GRUB_DISK_SECTOR_BITS); i < blockcnt; i++)
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{
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grub_disk_addr_t blknr;
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int blockoff = pos & (blocksize - 1);
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int blockend = blocksize;
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int skipfirst = 0;
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blknr = get_block (node, i);
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if (grub_errno)
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return -1;
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blknr = blknr << log2blocksize;
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/* Last block. */
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if (i == blockcnt - 1)
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{
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blockend = (len + pos) & (blocksize - 1);
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/* The last portion is exactly blocksize. */
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if (! blockend)
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blockend = blocksize;
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}
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/* First block. */
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if (i == (pos >> (log2blocksize + GRUB_DISK_SECTOR_BITS)))
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{
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skipfirst = blockoff;
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blockend -= skipfirst;
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}
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/* If the block number is 0 this block is not stored on disk but
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is zero filled instead. */
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if (blknr)
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{
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disk->read_hook = read_hook;
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disk->read_hook_data = read_hook_data;
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grub_disk_read (disk, blknr + blocks_start, skipfirst,
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blockend, buf);
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disk->read_hook = 0;
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if (grub_errno)
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return -1;
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}
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else if (read_hook != (grub_disk_read_hook_t)grub_disk_blocklist_read)
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grub_memset (buf, 0, blockend);
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buf += blocksize - skipfirst;
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}
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return len;
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}
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@ -0,0 +1,5 @@
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Ventoy Logo was downloaded from https://www.easyicon.net/29165-usb_icon.html
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As descripted in the website:
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Author: Ahmad Hania
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License: Creative Commons (Attribution-Noncommercial-Share Alike 3.0 Unported)
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