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fat_fuse_ops.c
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fat_fuse_ops.c
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/*
* fat_fuse_ops.c
*
* FAT12/16/32 filesystem operations for FUSE (Filesystem in Userspace)
*/
#include "fat_fuse_ops.h"
#include "fat_file.h"
#include "fat_util.h"
#include <errno.h>
/* Retrieve the currently mounted FAT volume from the FUSE context. */
static inline struct fat_volume *
get_fat_volume()
{
return fuse_get_context()->private_data;
}
/* Get file attributes (file descriptor version) */
static int
fat_fuse_fgetattr(const char *path, struct stat *stbuf,
struct fuse_file_info *fi)
{
struct fat_file *file = (struct fat_file*)(uintptr_t)fi->fh;
return fat_file_to_stbuf(file, stbuf);
}
/* Get file attributes (path version) */
static int
fat_fuse_getattr(const char *path, struct stat *stbuf)
{
struct fat_volume *vol;
struct fat_file *file;
vol = get_fat_volume();
file = fat_pathname_to_file(vol, path);
if (!file)
return -errno;
return fat_file_to_stbuf(file, stbuf);
}
/* Open a file */
static int
fat_fuse_open(const char *path, struct fuse_file_info *fi)
{
struct fat_volume *vol;
struct fat_file *file;
vol = get_fat_volume();
file = fat_pathname_to_file(vol, path);
if (!file)
return -errno;
if (fat_file_is_directory(file))
return -EISDIR;
if (file->num_times_opened == 0)
if (fat_file_alloc_cluster_cache(file))
return -errno;
fat_file_inc_num_times_opened(file);
fi->fh = (uintptr_t)file;
return 0;
}
/* Open a directory */
static int
fat_fuse_opendir(const char *path, struct fuse_file_info *fi)
{
struct fat_volume *vol;
struct fat_file *file;
vol = get_fat_volume();
file = fat_pathname_to_file(vol, path);
if (!file)
return -errno;
if (!fat_file_is_directory(file))
return -ENOTDIR;
fat_file_inc_num_times_opened(file);
fi->fh = (uintptr_t)file;
return 0;
}
/* Read data from a file */
static int
fat_fuse_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
struct fat_file *file = (struct fat_file*)(uintptr_t)fi->fh;
return fat_file_pread(file, buf, size, offset);
}
/* Read the entries of a directory */
static int
fat_fuse_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
off_t offset, struct fuse_file_info *fi)
{
struct fat_file *dir = (struct fat_file*)(uintptr_t)fi->fh;
struct fat_file *child;
if ((*filler)(buf, ".", NULL, 0) ||
(*filler)(buf, "..", NULL, 0))
return -errno;
if (!dir->children_read)
if (fat_dir_read_children(dir))
return -errno;
fat_dir_for_each_child(child, dir)
if ((*filler)(buf, child->dentry.name, NULL, 0))
return -errno;
return 0;
}
/* Close a file */
static int
fat_fuse_release(const char *path, struct fuse_file_info *fi)
{
struct fat_file *file = (struct fat_file*)(uintptr_t)fi->fh;
fat_file_dec_num_times_opened(file);
if (file->num_times_opened == 0)
fat_file_free_cluster_cache(file);
return 0;
}
/* Close a directory */
static int
fat_fuse_releasedir(const char *path, struct fuse_file_info *fi)
{
struct fat_file *file = (struct fat_file*)(uintptr_t)fi->fh;
fat_file_dec_num_times_opened(file);
return 0;
}
/* Filesystem operations for FUSE. Only some of the possible operations are
* implemented (the rest stay as NULL pointers and are interpreted as not
* implemented by FUSE). */
struct fuse_operations fat_fuse_operations = {
.fgetattr = fat_fuse_fgetattr,
.getattr = fat_fuse_getattr,
.open = fat_fuse_open,
.opendir = fat_fuse_opendir,
.read = fat_fuse_read,
.readdir = fat_fuse_readdir,
.release = fat_fuse_release,
.releasedir = fat_fuse_releasedir,
/* We use `struct fat_file's as file handles, so we do not need to
* require that the file path be passed to operations such as read() */
#if FUSE_MAJOR_VERSION > 2 || (FUSE_MAJOR_VERSION == 2 && FUSE_MINOR_VERSION >= 8)
.flag_nullpath_ok = 1,
#endif
#if FUSE_MAJOR_VERSION > 2 || (FUSE_MAJOR_VERSION == 2 && FUSE_MINOR_VERSION >= 9)
.flag_nopath = 1,
#endif
};