162 lines
3.3 KiB
C
162 lines
3.3 KiB
C
/* file.c - file I/O functions */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2006,2007 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/misc.h>
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#include <grub/err.h>
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#include <grub/file.h>
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#include <grub/mm.h>
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#include <grub/fs.h>
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#include <grub/device.h>
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/* Get the device part of the filename NAME. It is enclosed by parentheses. */
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char *
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grub_file_get_device_name (const char *name)
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{
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if (name[0] == '(')
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{
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char *p = grub_strchr (name, ')');
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char *ret;
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if (! p)
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{
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grub_error (GRUB_ERR_BAD_FILENAME, "missing `)'");
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return 0;
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}
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ret = (char *) grub_malloc (p - name);
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if (! ret)
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return 0;
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grub_memcpy (ret, name + 1, p - name - 1);
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ret[p - name - 1] = '\0';
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return ret;
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}
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return 0;
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}
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grub_file_t
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grub_file_open (const char *name)
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{
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grub_device_t device;
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grub_file_t file = 0;
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char *device_name;
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char *file_name;
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device_name = grub_file_get_device_name (name);
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if (grub_errno)
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return 0;
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/* Get the file part of NAME. */
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file_name = grub_strchr (name, ')');
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if (file_name)
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file_name++;
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else
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file_name = (char *) name;
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device = grub_device_open (device_name);
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grub_free (device_name);
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if (! device)
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goto fail;
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file = (grub_file_t) grub_malloc (sizeof (*file));
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if (! file)
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goto fail;
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file->device = device;
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file->offset = 0;
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file->data = 0;
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file->read_hook = 0;
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if (device->disk && file_name[0] != '/')
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/* This is a block list. */
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file->fs = &grub_fs_blocklist;
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else
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{
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file->fs = grub_fs_probe (device);
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if (! file->fs)
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goto fail;
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}
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if ((file->fs->open) (file, file_name) != GRUB_ERR_NONE)
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goto fail;
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return file;
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fail:
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if (device)
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grub_device_close (device);
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/* if (net) grub_net_close (net); */
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grub_free (file);
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return 0;
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}
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grub_ssize_t
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grub_file_read (grub_file_t file, void *buf, grub_size_t len)
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{
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grub_ssize_t res;
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if (len == 0 || len > file->size - file->offset)
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len = file->size - file->offset;
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/* Prevent an overflow. */
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if ((grub_ssize_t) len < 0)
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len >>= 1;
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if (len == 0)
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return 0;
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res = (file->fs->read) (file, buf, len);
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if (res > 0)
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file->offset += res;
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return res;
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}
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grub_err_t
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grub_file_close (grub_file_t file)
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{
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if (file->fs->close)
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(file->fs->close) (file);
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if (file->device)
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grub_device_close (file->device);
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grub_free (file);
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return grub_errno;
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}
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grub_off_t
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grub_file_seek (grub_file_t file, grub_off_t offset)
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{
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grub_off_t old;
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if (offset > file->size)
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{
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grub_error (GRUB_ERR_OUT_OF_RANGE,
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"attempt to seek outside of the file");
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return -1;
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}
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old = file->offset;
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file->offset = offset;
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return old;
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}
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