You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
112 lines
2.2 KiB
112 lines
2.2 KiB
4 months ago
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
/*
|
||
|
|
* memfd test file-system
|
||
|
|
* This file uses FUSE to create a dummy file-system with only one file /memfd.
|
||
|
|
* This file is read-only and takes 1s per read.
|
||
|
|
*
|
||
|
|
* This file-system is used by the memfd test-cases to force the kernel to pin
|
||
|
|
* pages during reads(). Due to the 1s delay of this file-system, this is a
|
||
|
|
* nice way to test race-conditions against get_user_pages() in the kernel.
|
||
|
|
*
|
||
|
|
* We use direct_io==1 to force the kernel to use direct-IO for this
|
||
|
|
* file-system.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define FUSE_USE_VERSION 26
|
||
|
|
|
||
|
|
#include <fuse.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
static const char memfd_content[] = "memfd-example-content";
|
||
|
|
static const char memfd_path[] = "/memfd";
|
||
|
|
|
||
|
|
static int memfd_getattr(const char *path, struct stat *st)
|
||
|
|
{
|
||
|
|
memset(st, 0, sizeof(*st));
|
||
|
|
|
||
|
|
if (!strcmp(path, "/")) {
|
||
|
|
st->st_mode = S_IFDIR | 0755;
|
||
|
|
st->st_nlink = 2;
|
||
|
|
} else if (!strcmp(path, memfd_path)) {
|
||
|
|
st->st_mode = S_IFREG | 0444;
|
||
|
|
st->st_nlink = 1;
|
||
|
|
st->st_size = strlen(memfd_content);
|
||
|
|
} else {
|
||
|
|
return -ENOENT;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int memfd_readdir(const char *path,
|
||
|
|
void *buf,
|
||
|
|
fuse_fill_dir_t filler,
|
||
|
|
off_t offset,
|
||
|
|
struct fuse_file_info *fi)
|
||
|
|
{
|
||
|
|
if (strcmp(path, "/"))
|
||
|
|
return -ENOENT;
|
||
|
|
|
||
|
|
filler(buf, ".", NULL, 0);
|
||
|
|
filler(buf, "..", NULL, 0);
|
||
|
|
filler(buf, memfd_path + 1, NULL, 0);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int memfd_open(const char *path, struct fuse_file_info *fi)
|
||
|
|
{
|
||
|
|
if (strcmp(path, memfd_path))
|
||
|
|
return -ENOENT;
|
||
|
|
|
||
|
|
if ((fi->flags & 3) != O_RDONLY)
|
||
|
|
return -EACCES;
|
||
|
|
|
||
|
|
/* force direct-IO */
|
||
|
|
fi->direct_io = 1;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int memfd_read(const char *path,
|
||
|
|
char *buf,
|
||
|
|
size_t size,
|
||
|
|
off_t offset,
|
||
|
|
struct fuse_file_info *fi)
|
||
|
|
{
|
||
|
|
size_t len;
|
||
|
|
|
||
|
|
if (strcmp(path, memfd_path) != 0)
|
||
|
|
return -ENOENT;
|
||
|
|
|
||
|
|
sleep(1);
|
||
|
|
|
||
|
|
len = strlen(memfd_content);
|
||
|
|
if (offset < len) {
|
||
|
|
if (offset + size > len)
|
||
|
|
size = len - offset;
|
||
|
|
|
||
|
|
memcpy(buf, memfd_content + offset, size);
|
||
|
|
} else {
|
||
|
|
size = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return size;
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct fuse_operations memfd_ops = {
|
||
|
|
.getattr = memfd_getattr,
|
||
|
|
.readdir = memfd_readdir,
|
||
|
|
.open = memfd_open,
|
||
|
|
.read = memfd_read,
|
||
|
|
};
|
||
|
|
|
||
|
|
int main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
return fuse_main(argc, argv, &memfd_ops, NULL);
|
||
|
|
}
|