passthrough_helpers.h

/*
 * FUSE: Filesystem in Userspace
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE
 */
 
#ifndef FUSE_EXAMPLE_PASSTHROUGH_HELPERS_H_
#define FUSE_EXAMPLE_PASSTHROUGH_HELPERS_H_
 
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
 
#ifdef __FreeBSD__
#include <sys/socket.h>
#include <sys/un.h>
#endif
 
static inline int do_fallocate(int fd, int mode, off_t offset, off_t length)
{
#ifdef HAVE_FALLOCATE
        if (fallocate(fd, mode, offset, length) == -1)
                return -errno;
        return 0;
#else  // HAVE_FALLOCATE
 
#ifdef HAVE_POSIX_FALLOCATE
        if (mode == 0)
                return -posix_fallocate(fd, offset, length);
#endif
 
#ifdef HAVE_FSPACECTL
        // 0x3 == FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE
        if (mode == 0x3) {
                struct spacectl_range sr;
 
                sr.r_offset = offset;
                sr.r_len = length;
                if (fspacectl(fd, SPACECTL_DEALLOC, &sr, 0, NULL) == -1)
                        return -errno;
                return 0;
        }
#endif
 
        return -EOPNOTSUPP;
#endif  // HAVE_FALLOCATE
}
 
/*
 * Creates files on the underlying file system in response to a FUSE_MKNOD
 * operation
 */
static inline int mknod_wrapper(int dirfd, const char *path, const char *link,
        int mode, dev_t rdev)
{
        int res;
 
        if (S_ISREG(mode)) {
                res = openat(dirfd, path, O_CREAT | O_EXCL | O_WRONLY, mode);
                if (res >= 0)
                        res = close(res);
        } else if (S_ISDIR(mode)) {
                res = mkdirat(dirfd, path, mode);
        } else if (S_ISLNK(mode) && link != NULL) {
                res = symlinkat(link, dirfd, path);
        } else if (S_ISFIFO(mode)) {
                res = mkfifoat(dirfd, path, mode);
#ifdef __FreeBSD__
        } else if (S_ISSOCK(mode)) {
                struct sockaddr_un su;
                int fd;
 
                if (strlen(path) >= sizeof(su.sun_path)) {
                        errno = ENAMETOOLONG;
                        return -1;
                }
                fd = socket(AF_UNIX, SOCK_STREAM, 0);
                if (fd >= 0) {
                        /*
                         * We must bind the socket to the underlying file
                         * system to create the socket file, even though
                         * we'll never listen on this socket.
                         */
                        su.sun_family = AF_UNIX;
                        strncpy(su.sun_path, path, sizeof(su.sun_path));
                        res = bindat(dirfd, fd, (struct sockaddr*)&su,
                                sizeof(su));
                        if (res == 0)
                                close(fd);
                } else {
                        res = -1;
                }
#endif
        } else {
                res = mknodat(dirfd, path, mode, rdev);
        }
 
        return res;
}
 
#endif  // FUSE_PASSTHROUGH_HELPERS_H_