diff options
Diffstat (limited to 'grub-core/kern/file.c')
| -rw-r--r-- | grub-core/kern/file.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/grub-core/kern/file.c b/grub-core/kern/file.c new file mode 100644 index 0000000..9d5a51c --- /dev/null +++ b/grub-core/kern/file.c @@ -0,0 +1,186 @@ +/* file.c - file I/O functions */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2002,2006,2007,2009 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/misc.h> +#include <grub/err.h> +#include <grub/file.h> +#include <grub/mm.h> +#include <grub/fs.h> +#include <grub/device.h> + +grub_file_filter_t grub_file_filters_all[GRUB_FILE_FILTER_MAX]; +grub_file_filter_t grub_file_filters_enabled[GRUB_FILE_FILTER_MAX]; + +/* Get the device part of the filename NAME. It is enclosed by parentheses. */ +char * +grub_file_get_device_name (const char *name) +{ + if (name[0] == '(') + { + char *p = grub_strchr (name, ')'); + char *ret; + + if (! p) + { + grub_error (GRUB_ERR_BAD_FILENAME, "missing `)'"); + return 0; + } + + ret = (char *) grub_malloc (p - name); + if (! ret) + return 0; + + grub_memcpy (ret, name + 1, p - name - 1); + ret[p - name - 1] = '\0'; + return ret; + } + + return 0; +} + +grub_file_t +grub_file_open (const char *name) +{ + grub_device_t device = 0; + grub_file_t file = 0, last_file = 0; + char *device_name; + char *file_name; + grub_file_filter_id_t filter; + + device_name = grub_file_get_device_name (name); + if (grub_errno) + goto fail; + + /* Get the file part of NAME. */ + file_name = (name[0] == '(') ? grub_strchr (name, ')') : NULL; + if (file_name) + file_name++; + else + file_name = (char *) name; + + device = grub_device_open (device_name); + grub_free (device_name); + if (! device) + goto fail; + + file = (grub_file_t) grub_zalloc (sizeof (*file)); + if (! file) + goto fail; + + file->device = device; + + if (device->disk && file_name[0] != '/') + /* This is a block list. */ + file->fs = &grub_fs_blocklist; + else + { + file->fs = grub_fs_probe (device); + if (! file->fs) + goto fail; + } + + if ((file->fs->open) (file, file_name) != GRUB_ERR_NONE) + goto fail; + + for (filter = 0; file && filter < ARRAY_SIZE (grub_file_filters_enabled); + filter++) + if (grub_file_filters_enabled[filter]) + { + last_file = file; + file = grub_file_filters_enabled[filter] (file); + } + if (!file) + grub_file_close (last_file); + + grub_memcpy (grub_file_filters_enabled, grub_file_filters_all, + sizeof (grub_file_filters_enabled)); + + return file; + + fail: + if (device) + grub_device_close (device); + + /* if (net) grub_net_close (net); */ + + grub_free (file); + + grub_memcpy (grub_file_filters_enabled, grub_file_filters_all, + sizeof (grub_file_filters_enabled)); + + return 0; +} + +grub_ssize_t +grub_file_read (grub_file_t file, void *buf, grub_size_t len) +{ + grub_ssize_t res; + + if (file->offset > file->size) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, + "attempt to read past the end of file"); + return -1; + } + + if (len == 0 || len > file->size - file->offset) + len = file->size - file->offset; + + /* Prevent an overflow. */ + if ((grub_ssize_t) len < 0) + len >>= 1; + + if (len == 0) + return 0; + + res = (file->fs->read) (file, buf, len); + if (res > 0) + file->offset += res; + + return res; +} + +grub_err_t +grub_file_close (grub_file_t file) +{ + if (file->fs->close) + (file->fs->close) (file); + + if (file->device) + grub_device_close (file->device); + grub_free (file); + return grub_errno; +} + +grub_off_t +grub_file_seek (grub_file_t file, grub_off_t offset) +{ + grub_off_t old; + + if (offset > file->size) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, + "attempt to seek outside of the file"); + return -1; + } + + old = file->offset; + file->offset = offset; + return old; +} |