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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
gcc -Wall hello_ll.c `pkg-config fuse --cflags --libs` -o hello_ll
*/
#define FUSE_USE_VERSION 26
#include <fuse_lowlevel.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
static const char *hello_str = "Hello World!\n";
static const char *hello_name = "hello";
static int hello_stat(fuse_ino_t ino, struct stat *stbuf)
{
stbuf->st_ino = ino;
switch (ino) {
case 1:
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
break;
case 2:
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = strlen(hello_str);
break;
default:
return -1;
}
return 0;
}
static void hello_ll_getattr(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
struct stat stbuf;
(void) fi;
memset(&stbuf, 0, sizeof(stbuf));
if (hello_stat(ino, &stbuf) == -1)
fuse_reply_err(req, ENOENT);
else
fuse_reply_attr(req, &stbuf, 1.0);
}
static void hello_ll_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
{
struct fuse_entry_param e;
if (parent != 1 || strcmp(name, hello_name) != 0)
fuse_reply_err(req, ENOENT);
else {
memset(&e, 0, sizeof(e));
e.ino = 2;
e.attr_timeout = 1.0;
e.entry_timeout = 1.0;
hello_stat(e.ino, &e.attr);
fuse_reply_entry(req, &e);
}
}
struct dirbuf {
char *p;
size_t size;
};
static void dirbuf_add(fuse_req_t req, struct dirbuf *b, const char *name,
fuse_ino_t ino)
{
struct stat stbuf;
size_t oldsize = b->size;
b->size += fuse_add_direntry(req, NULL, 0, name, NULL, 0);
b->p = (char *) realloc(b->p, b->size);
memset(&stbuf, 0, sizeof(stbuf));
stbuf.st_ino = ino;
fuse_add_direntry(req, b->p + oldsize, b->size - oldsize, name, &stbuf,
b->size);
}
#define min(x, y) ((x) < (y) ? (x) : (y))
static int reply_buf_limited(fuse_req_t req, const char *buf, size_t bufsize,
off_t off, size_t maxsize)
{
if (off < bufsize)
return fuse_reply_buf(req, buf + off,
min(bufsize - off, maxsize));
else
return fuse_reply_buf(req, NULL, 0);
}
static void hello_ll_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t off, struct fuse_file_info *fi)
{
(void) fi;
if (ino != 1)
fuse_reply_err(req, ENOTDIR);
else {
struct dirbuf b;
memset(&b, 0, sizeof(b));
dirbuf_add(req, &b, ".", 1);
dirbuf_add(req, &b, "..", 1);
dirbuf_add(req, &b, hello_name, 2);
reply_buf_limited(req, b.p, b.size, off, size);
free(b.p);
}
}
static void hello_ll_open(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
if (ino != 2)
fuse_reply_err(req, EISDIR);
else if ((fi->flags & 3) != O_RDONLY)
fuse_reply_err(req, EACCES);
else
fuse_reply_open(req, fi);
}
static void hello_ll_read(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t off, struct fuse_file_info *fi)
{
(void) fi;
assert(ino == 2);
reply_buf_limited(req, hello_str, strlen(hello_str), off, size);
}
static struct fuse_lowlevel_ops hello_ll_oper = {
.lookup = hello_ll_lookup,
.getattr = hello_ll_getattr,
.readdir = hello_ll_readdir,
.open = hello_ll_open,
.read = hello_ll_read,
};
int main(int argc, char *argv[])
{
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
struct fuse_chan *ch;
char *mountpoint;
int err = -1;
if (fuse_parse_cmdline(&args, &mountpoint, NULL, NULL) != -1 &&
(ch = fuse_mount(mountpoint, &args)) != NULL) {
struct fuse_session *se;
se = fuse_lowlevel_new(&args, &hello_ll_oper,
sizeof(hello_ll_oper), NULL);
if (se != NULL) {
if (fuse_set_signal_handlers(se) != -1) {
fuse_session_add_chan(se, ch);
err = fuse_session_loop(se);
fuse_remove_signal_handlers(se);
fuse_session_remove_chan(ch);
}
fuse_session_destroy(se);
}
fuse_unmount(mountpoint, ch);
}
fuse_opt_free_args(&args);
return err ? 1 : 0;
}
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