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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.
*/
/** @file
*
* This "filesystem" provides only a single file. The mountpoint
* needs to be a file rather than a directory. All writes to the
* file will be discarded, and reading the file always returns
* \0.
*
* Compile with:
*
* gcc -Wall null.c `pkg-config fuse3 --cflags --libs` -o null
*
* ## Source code ##
* \include passthrough_fh.c
*/
#define FUSE_USE_VERSION 31
#include <fuse.h>
#include <fuse_lowlevel.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
static int null_getattr(const char *path, struct stat *stbuf,
struct fuse_file_info *fi)
{
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
stbuf->st_mode = S_IFREG | 0644;
stbuf->st_nlink = 1;
stbuf->st_uid = getuid();
stbuf->st_gid = getgid();
stbuf->st_size = (1ULL << 32); /* 4G */
stbuf->st_blocks = 0;
stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL);
return 0;
}
static int null_truncate(const char *path, off_t size,
struct fuse_file_info *fi)
{
(void) size;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return 0;
}
static int null_open(const char *path, struct fuse_file_info *fi)
{
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return 0;
}
static int null_read(const char *path, char *buf, size_t size,
off_t offset, struct fuse_file_info *fi)
{
(void) buf;
(void) offset;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
if (offset >= (1ULL << 32))
return 0;
memset(buf, 0, size);
return size;
}
static int null_write(const char *path, const char *buf, size_t size,
off_t offset, struct fuse_file_info *fi)
{
(void) buf;
(void) offset;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return size;
}
static struct fuse_operations null_oper = {
.getattr = null_getattr,
.truncate = null_truncate,
.open = null_open,
.read = null_read,
.write = null_write,
};
int main(int argc, char *argv[])
{
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
struct fuse_cmdline_opts opts;
struct stat stbuf;
if (fuse_parse_cmdline(&args, &opts) != 0)
return 1;
fuse_opt_free_args(&args);
if (!opts.mountpoint) {
fprintf(stderr, "missing mountpoint parameter\n");
return 1;
}
if (stat(opts.mountpoint, &stbuf) == -1) {
fprintf(stderr ,"failed to access mountpoint %s: %s\n",
opts.mountpoint, strerror(errno));
free(opts.mountpoint);
return 1;
}
free(opts.mountpoint);
if (!S_ISREG(stbuf.st_mode)) {
fprintf(stderr, "mountpoint is not a regular file\n");
return 1;
}
return fuse_main(argc, argv, &null_oper, NULL);
}
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