mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-11-24 11:45:27 +01:00
302 lines
8.9 KiB
C
302 lines
8.9 KiB
C
/* 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 char *(*read_symlink_func) (grub_fshelp_node_t node);
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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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const char *path;
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grub_fshelp_node_t rootnode, currroot, currnode, oldnode;
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enum grub_fshelp_filetype foundtype;
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int symlinknest;
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const char *name;
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const char *next;
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enum grub_fshelp_filetype type;
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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 && node != ctx->currroot)
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grub_free (node);
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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_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_strncasecmp (ctx->name, filename, ctx->next - ctx->name)
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: grub_strncmp (ctx->name, filename, ctx->next - ctx->name))
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|| filename[ctx->next - ctx->name]) {
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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->type = filetype & ~GRUB_FSHELP_CASE_INSENSITIVE;
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ctx->oldnode = ctx->currnode;
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ctx->currnode = node;
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return 1;
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}
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static grub_err_t
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find_file (const char *currpath, grub_fshelp_node_t currroot,
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grub_fshelp_node_t *currfound,
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iterate_dir_func iterate_dir, read_symlink_func read_symlink,
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struct grub_fshelp_find_file_ctx *ctx)
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{
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ctx->currroot = currroot;
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ctx->name = currpath;
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ctx->type = GRUB_FSHELP_DIR;
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ctx->currnode = currroot;
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ctx->oldnode = currroot;
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for (;;) {
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int found;
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/* Remove all leading slashes. */
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while (*ctx->name == '/')
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ctx->name++;
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/* Found the node! */
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if (! *ctx->name) {
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*currfound = ctx->currnode;
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ctx->foundtype = ctx->type;
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return 0;
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}
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/* Extract the actual part from the pathname. */
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for (ctx->next = ctx->name; *ctx->next && *ctx->next != '/'; ctx->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->type != GRUB_FSHELP_DIR) {
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free_node (ctx->currnode, ctx);
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ctx->currnode = 0;
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory"));
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}
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/* Iterate over the directory. */
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found = iterate_dir (ctx->currnode, find_file_iter, ctx);
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if (! found) {
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free_node (ctx->currnode, ctx);
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ctx->currnode = 0;
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if (grub_errno)
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return grub_errno;
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break;
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}
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/* Read in the symlink and follow it. */
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if (ctx->type == GRUB_FSHELP_SYMLINK) {
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char *symlink;
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const char *next;
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/* Test if the symlink does not loop. */
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if (++ctx->symlinknest == 8) {
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free_node (ctx->currnode, ctx);
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free_node (ctx->oldnode, ctx);
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ctx->currnode = 0;
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ctx->oldnode = 0;
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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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}
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symlink = read_symlink (ctx->currnode);
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free_node (ctx->currnode, ctx);
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ctx->currnode = 0;
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if (!symlink) {
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free_node (ctx->oldnode, ctx);
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ctx->oldnode = 0;
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return grub_errno;
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}
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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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free_node (ctx->oldnode, ctx);
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ctx->oldnode = ctx->rootnode;
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}
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/* Lookup the node the symlink points to. */
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next = ctx->next;
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find_file (symlink, ctx->oldnode, &ctx->currnode,
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iterate_dir, read_symlink, ctx);
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ctx->next = next;
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ctx->type = ctx->foundtype;
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grub_free (symlink);
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if (grub_errno) {
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free_node (ctx->oldnode, ctx);
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ctx->oldnode = 0;
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return grub_errno;
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}
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}
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if (ctx->oldnode != ctx->currnode) {
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free_node (ctx->oldnode, ctx);
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ctx->oldnode = 0;
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}
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ctx->name = ctx->next;
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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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/* 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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struct grub_fshelp_find_file_ctx ctx = {
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.path = path,
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.rootnode = rootnode,
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.foundtype = GRUB_FSHELP_DIR,
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.symlinknest = 0
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};
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grub_err_t err;
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if (!path || path[0] != '/') {
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grub_error (GRUB_ERR_BAD_FILENAME, N_("invalid file name `%s'"), path);
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return grub_errno;
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}
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err = find_file (path, rootnode, foundnode, iterate_dir, read_symlink, &ctx);
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if (err)
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return err;
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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 && ctx.foundtype != expecttype) {
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a regular file"));
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}
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else if (expecttype == GRUB_FSHELP_DIR && ctx.foundtype != expecttype) {
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return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory"));
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}
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return 0;
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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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/* 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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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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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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}
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/* First block. */
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if (i == (pos >> (log2blocksize + GRUB_DISK_SECTOR_BITS))) {
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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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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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}
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else {
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grub_memset (buf, 0, blockend);
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}
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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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