mirror of
https://github.com/libfuse/libfuse.git
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490 lines
8.5 KiB
C
490 lines
8.5 KiB
C
/*
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FUSE: Filesystem in Userspace
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Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
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Copyright (C) 2011 Sebastian Pipping <sebastian@pipping.org>
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This program can be distributed under the terms of the GNU GPL.
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See the file COPYING.
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*/
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/** @file
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*
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* This file system mirrors the existing file system hierarchy of the
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* system, starting at the root file system. This is implemented by
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* just "passing through" all requests to the corresponding user-space
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* libc functions. Its performance is terrible.
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*
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* Compile with
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*
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* gcc -Wall passthrough.c `pkg-config fuse3 --cflags --libs` -o passthrough
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*
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* ## Source code ##
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* \include passthrough.c
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*/
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#define FUSE_USE_VERSION 31
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef linux
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/* For pread()/pwrite()/utimensat() */
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#define _XOPEN_SOURCE 700
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#endif
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#include <fuse.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <errno.h>
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#include <sys/time.h>
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#ifdef HAVE_SETXATTR
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#include <sys/xattr.h>
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#endif
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static void *xmp_init(struct fuse_conn_info *conn,
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struct fuse_config *cfg)
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{
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(void) conn;
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cfg->use_ino = 1;
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/* Pick up changes from lower filesystem right away. This is
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also necessary for better hardlink support. When the kernel
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calls the unlink() handler, it does not know the inode of
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the to-be-removed entry and can therefore not invalidate
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the cache of the associated inode - resulting in an
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incorrect st_nlink value being reported for any remaining
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hardlinks to this inode. */
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cfg->entry_timeout = 0;
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cfg->attr_timeout = 0;
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cfg->negative_timeout = 0;
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return NULL;
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}
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static int xmp_getattr(const char *path, struct stat *stbuf,
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struct fuse_file_info *fi)
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{
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(void) fi;
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int res;
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res = lstat(path, stbuf);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_access(const char *path, int mask)
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{
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int res;
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res = access(path, mask);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_readlink(const char *path, char *buf, size_t size)
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{
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int res;
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res = readlink(path, buf, size - 1);
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if (res == -1)
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return -errno;
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buf[res] = '\0';
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return 0;
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}
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static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
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off_t offset, struct fuse_file_info *fi,
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enum fuse_readdir_flags flags)
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{
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DIR *dp;
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struct dirent *de;
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(void) offset;
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(void) fi;
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(void) flags;
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dp = opendir(path);
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if (dp == NULL)
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return -errno;
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while ((de = readdir(dp)) != NULL) {
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struct stat st;
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memset(&st, 0, sizeof(st));
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st.st_ino = de->d_ino;
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st.st_mode = de->d_type << 12;
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if (filler(buf, de->d_name, &st, 0, 0))
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break;
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}
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closedir(dp);
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return 0;
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}
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static int xmp_mknod(const char *path, mode_t mode, dev_t rdev)
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{
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int res;
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/* On Linux this could just be 'mknod(path, mode, rdev)' but this
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is more portable */
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if (S_ISREG(mode)) {
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res = open(path, O_CREAT | O_EXCL | O_WRONLY, mode);
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if (res >= 0)
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res = close(res);
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} else if (S_ISFIFO(mode))
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res = mkfifo(path, mode);
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else
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res = mknod(path, mode, rdev);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_mkdir(const char *path, mode_t mode)
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{
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int res;
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res = mkdir(path, mode);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_unlink(const char *path)
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{
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int res;
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res = unlink(path);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_rmdir(const char *path)
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{
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int res;
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res = rmdir(path);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_symlink(const char *from, const char *to)
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{
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int res;
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res = symlink(from, to);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_rename(const char *from, const char *to, unsigned int flags)
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{
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int res;
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if (flags)
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return -EINVAL;
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res = rename(from, to);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_link(const char *from, const char *to)
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{
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int res;
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res = link(from, to);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_chmod(const char *path, mode_t mode,
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struct fuse_file_info *fi)
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{
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(void) fi;
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int res;
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res = chmod(path, mode);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_chown(const char *path, uid_t uid, gid_t gid,
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struct fuse_file_info *fi)
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{
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(void) fi;
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int res;
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res = lchown(path, uid, gid);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_truncate(const char *path, off_t size,
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struct fuse_file_info *fi)
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{
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int res;
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if (fi != NULL)
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res = ftruncate(fi->fh, size);
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else
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res = truncate(path, size);
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if (res == -1)
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return -errno;
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return 0;
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}
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#ifdef HAVE_UTIMENSAT
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static int xmp_utimens(const char *path, const struct timespec ts[2],
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struct fuse_file_info *fi)
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{
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(void) fi;
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int res;
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/* don't use utime/utimes since they follow symlinks */
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res = utimensat(0, path, ts, AT_SYMLINK_NOFOLLOW);
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if (res == -1)
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return -errno;
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return 0;
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}
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#endif
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static int xmp_create(const char *path, mode_t mode,
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struct fuse_file_info *fi)
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{
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int res;
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res = open(path, fi->flags, mode);
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if (res == -1)
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return -errno;
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fi->fh = res;
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return 0;
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}
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static int xmp_open(const char *path, struct fuse_file_info *fi)
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{
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int res;
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res = open(path, fi->flags);
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if (res == -1)
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return -errno;
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fi->fh = res;
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return 0;
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}
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static int xmp_read(const char *path, char *buf, size_t size, off_t offset,
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struct fuse_file_info *fi)
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{
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int fd;
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int res;
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if(fi == NULL)
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fd = open(path, O_RDONLY);
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else
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fd = fi->fh;
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if (fd == -1)
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return -errno;
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res = pread(fd, buf, size, offset);
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if (res == -1)
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res = -errno;
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if(fi == NULL)
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close(fd);
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return res;
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}
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static int xmp_write(const char *path, const char *buf, size_t size,
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off_t offset, struct fuse_file_info *fi)
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{
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int fd;
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int res;
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(void) fi;
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if(fi == NULL)
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fd = open(path, O_WRONLY);
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else
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fd = fi->fh;
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if (fd == -1)
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return -errno;
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res = pwrite(fd, buf, size, offset);
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if (res == -1)
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res = -errno;
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if(fi == NULL)
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close(fd);
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return res;
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}
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static int xmp_statfs(const char *path, struct statvfs *stbuf)
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{
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int res;
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res = statvfs(path, stbuf);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_release(const char *path, struct fuse_file_info *fi)
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{
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(void) path;
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close(fi->fh);
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return 0;
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}
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static int xmp_fsync(const char *path, int isdatasync,
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struct fuse_file_info *fi)
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{
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/* Just a stub. This method is optional and can safely be left
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unimplemented */
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(void) path;
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(void) isdatasync;
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(void) fi;
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return 0;
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}
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#ifdef HAVE_POSIX_FALLOCATE
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static int xmp_fallocate(const char *path, int mode,
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off_t offset, off_t length, struct fuse_file_info *fi)
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{
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int fd;
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int res;
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(void) fi;
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if (mode)
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return -EOPNOTSUPP;
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if(fi == NULL)
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fd = open(path, O_WRONLY);
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else
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fd = fi->fh;
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if (fd == -1)
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return -errno;
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res = -posix_fallocate(fd, offset, length);
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if(fi == NULL)
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close(fd);
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return res;
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}
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#endif
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#ifdef HAVE_SETXATTR
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/* xattr operations are optional and can safely be left unimplemented */
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static int xmp_setxattr(const char *path, const char *name, const char *value,
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size_t size, int flags)
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{
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int res = lsetxattr(path, name, value, size, flags);
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if (res == -1)
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return -errno;
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return 0;
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}
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static int xmp_getxattr(const char *path, const char *name, char *value,
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size_t size)
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{
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int res = lgetxattr(path, name, value, size);
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if (res == -1)
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return -errno;
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return res;
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}
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static int xmp_listxattr(const char *path, char *list, size_t size)
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{
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int res = llistxattr(path, list, size);
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if (res == -1)
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return -errno;
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return res;
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}
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static int xmp_removexattr(const char *path, const char *name)
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{
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int res = lremovexattr(path, name);
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if (res == -1)
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return -errno;
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return 0;
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}
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#endif /* HAVE_SETXATTR */
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static struct fuse_operations xmp_oper = {
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.init = xmp_init,
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.getattr = xmp_getattr,
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.access = xmp_access,
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.readlink = xmp_readlink,
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.readdir = xmp_readdir,
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.mknod = xmp_mknod,
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.mkdir = xmp_mkdir,
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.symlink = xmp_symlink,
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.unlink = xmp_unlink,
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.rmdir = xmp_rmdir,
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.rename = xmp_rename,
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.link = xmp_link,
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.chmod = xmp_chmod,
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.chown = xmp_chown,
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.truncate = xmp_truncate,
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#ifdef HAVE_UTIMENSAT
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.utimens = xmp_utimens,
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#endif
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.open = xmp_open,
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.create = xmp_create,
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.read = xmp_read,
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.write = xmp_write,
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.statfs = xmp_statfs,
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.release = xmp_release,
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.fsync = xmp_fsync,
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#ifdef HAVE_POSIX_FALLOCATE
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.fallocate = xmp_fallocate,
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#endif
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#ifdef HAVE_SETXATTR
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.setxattr = xmp_setxattr,
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.getxattr = xmp_getxattr,
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.listxattr = xmp_listxattr,
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.removexattr = xmp_removexattr,
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#endif
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};
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int main(int argc, char *argv[])
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{
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umask(0);
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return fuse_main(argc, argv, &xmp_oper, NULL);
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}
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