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https://github.com/trapexit/mergerfs.git
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104 lines
2.2 KiB
C
104 lines
2.2 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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This program can be distributed under the terms of the GNU LGPLv2.
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See the file COPYING.LIB
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*/
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#include "fuse_lowlevel.h"
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#include "fuse_kernel.h"
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#include "fuse_i.h"
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include <assert.h>
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static int fuse_kern_chan_receive(struct fuse_chan **chp, char *buf,
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size_t size)
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{
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struct fuse_chan *ch = *chp;
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int err;
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ssize_t res;
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struct fuse_session *se = fuse_chan_session(ch);
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assert(se != NULL);
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restart:
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res = read(fuse_chan_fd(ch), buf, size);
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err = errno;
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if (fuse_session_exited(se))
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return 0;
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if (res == -1) {
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/* ENOENT means the operation was interrupted, it's safe
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to restart */
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if (err == ENOENT)
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goto restart;
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if (err == ENODEV) {
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fuse_session_exit(se);
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return 0;
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}
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/* Errors occurring during normal operation: EINTR (read
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interrupted), EAGAIN (nonblocking I/O), ENODEV (filesystem
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umounted) */
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if (err != EINTR && err != EAGAIN)
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perror("fuse: reading device");
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return -err;
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}
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if ((size_t) res < sizeof(struct fuse_in_header)) {
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fprintf(stderr, "short read on fuse device\n");
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return -EIO;
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}
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return res;
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}
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static int fuse_kern_chan_send(struct fuse_chan *ch, const struct iovec iov[],
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size_t count)
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{
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if (iov) {
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ssize_t res = writev(fuse_chan_fd(ch), iov, count);
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int err = errno;
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if (res == -1) {
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struct fuse_session *se = fuse_chan_session(ch);
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assert(se != NULL);
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/* ENOENT means the operation was interrupted */
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if (!fuse_session_exited(se) && err != ENOENT)
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perror("fuse: writing device");
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return -err;
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}
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}
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return 0;
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}
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static void fuse_kern_chan_destroy(struct fuse_chan *ch)
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{
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int fd = fuse_chan_fd(ch);
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if (fd != -1)
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close(fd);
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}
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struct fuse_chan *
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fuse_kern_chan_new(int fd_)
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{
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long pagesize;
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size_t bufsize;
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struct fuse_chan_ops op =
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{
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.receive = fuse_kern_chan_receive,
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.send = fuse_kern_chan_send,
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.destroy = fuse_kern_chan_destroy,
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};
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pagesize = sysconf(_SC_PAGESIZE);
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bufsize = ((FUSE_MAX_MAX_PAGES * pagesize) + 0x1000);
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return fuse_chan_new(&op, fd_, bufsize, NULL);
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}
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