blob: 0afec4b6e91f5cf16876b264faf88eafcfe2731f
| 1 | /* |
| 2 | FUSE: Filesystem in Userspace |
| 3 | Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu> |
| 4 | |
| 5 | This program can be distributed under the terms of the GNU LGPLv2. |
| 6 | See the file COPYING.LIB |
| 7 | */ |
| 8 | |
| 9 | #include "config.h" |
| 10 | #include "fuse_lowlevel.h" |
| 11 | #include "fuse_kernel.h" |
| 12 | #include "fuse_i.h" |
| 13 | |
| 14 | #include <stdio.h> |
| 15 | #include <errno.h> |
| 16 | #include <unistd.h> |
| 17 | #include <assert.h> |
| 18 | |
| 19 | static int fuse_kern_chan_receive(struct fuse_chan **chp, char *buf, |
| 20 | size_t size) |
| 21 | { |
| 22 | struct fuse_chan *ch = *chp; |
| 23 | int err; |
| 24 | ssize_t res; |
| 25 | struct fuse_session *se = fuse_chan_session(ch); |
| 26 | assert(se != NULL); |
| 27 | |
| 28 | restart: |
| 29 | res = read(fuse_chan_fd(ch), buf, size); |
| 30 | err = errno; |
| 31 | |
| 32 | if (fuse_session_exited(se)) |
| 33 | return 0; |
| 34 | if (res == -1) { |
| 35 | /* ENOENT means the operation was interrupted, it's safe |
| 36 | to restart */ |
| 37 | if (err == ENOENT) |
| 38 | goto restart; |
| 39 | |
| 40 | if (err == ENODEV) { |
| 41 | fuse_session_exit(se); |
| 42 | return 0; |
| 43 | } |
| 44 | /* Errors occuring during normal operation: EINTR (read |
| 45 | interrupted), EAGAIN (nonblocking I/O), ENODEV (filesystem |
| 46 | umounted) */ |
| 47 | if (err != EINTR && err != EAGAIN) |
| 48 | perror("fuse: reading device"); |
| 49 | return -err; |
| 50 | } |
| 51 | if ((size_t) res < sizeof(struct fuse_in_header)) { |
| 52 | fprintf(stderr, "short read on fuse device\n"); |
| 53 | return -EIO; |
| 54 | } |
| 55 | return res; |
| 56 | } |
| 57 | |
| 58 | static int fuse_kern_chan_send(struct fuse_chan *ch, const struct iovec iov[], |
| 59 | size_t count) |
| 60 | { |
| 61 | if (iov) { |
| 62 | ssize_t res = writev(fuse_chan_fd(ch), iov, count); |
| 63 | int err = errno; |
| 64 | |
| 65 | if (res == -1) { |
| 66 | struct fuse_session *se = fuse_chan_session(ch); |
| 67 | |
| 68 | assert(se != NULL); |
| 69 | |
| 70 | /* ENOENT means the operation was interrupted */ |
| 71 | if (!fuse_session_exited(se) && err != ENOENT) |
| 72 | perror("fuse: writing device"); |
| 73 | return -err; |
| 74 | } |
| 75 | } |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static void fuse_kern_chan_destroy(struct fuse_chan *ch) |
| 80 | { |
| 81 | close(fuse_chan_fd(ch)); |
| 82 | } |
| 83 | |
| 84 | #define MIN_BUFSIZE 0x101000 |
| 85 | |
| 86 | struct fuse_chan *fuse_kern_chan_new(int fd) |
| 87 | { |
| 88 | struct fuse_chan_ops op = { |
| 89 | .receive = fuse_kern_chan_receive, |
| 90 | .send = fuse_kern_chan_send, |
| 91 | .destroy = fuse_kern_chan_destroy, |
| 92 | }; |
| 93 | size_t bufsize = getpagesize() + 0x1000; |
| 94 | bufsize = bufsize < MIN_BUFSIZE ? MIN_BUFSIZE : bufsize; |
| 95 | return fuse_chan_new(&op, fd, bufsize, NULL); |
| 96 | } |
| 97 |