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// SPDX-License-Identifier: GPL-2.0
/*
* fusectl test file-system
* Creates a simple FUSE filesystem with a single read-write file (/test)
*/
#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#define MAX(a, b) ((a) > (b) ? (a) : (b))
static char *content;
static size_t content_size = 0;
static const char test_path[] = "/test";
static int test_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;
return 0;
}
if (!strcmp(path, test_path)) {
st->st_mode = S_IFREG | 0664;
st->st_nlink = 1;
st->st_size = content_size;
return 0;
}
return -ENOENT;
}
static int test_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, test_path + 1, NULL, 0);
return 0;
}
static int test_open(const char *path, struct fuse_file_info *fi)
{
if (strcmp(path, test_path))
return -ENOENT;
return 0;
}
static int test_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
if (strcmp(path, test_path) != 0)
return -ENOENT;
if (!content || content_size == 0)
return 0;
if (offset >= content_size)
return 0;
if (offset + size > content_size)
size = content_size - offset;
memcpy(buf, content + offset, size);
return size;
}
static int test_write(const char *path, const char *buf, size_t size,
off_t offset, struct fuse_file_info *fi)
{
size_t new_size;
if (strcmp(path, test_path) != 0)
return -ENOENT;
if(offset > content_size)
return -EINVAL;
new_size = MAX(offset + size, content_size);
if (new_size > content_size)
content = realloc(content, new_size);
content_size = new_size;
if (!content)
return -ENOMEM;
memcpy(content + offset, buf, size);
return size;
}
static int test_truncate(const char *path, off_t size)
{
if (strcmp(path, test_path) != 0)
return -ENOENT;
if (size == 0) {
free(content);
content = NULL;
content_size = 0;
return 0;
}
content = realloc(content, size);
if (!content)
return -ENOMEM;
if (size > content_size)
memset(content + content_size, 0, size - content_size);
content_size = size;
return 0;
}
static struct fuse_operations memfd_ops = {
.getattr = test_getattr,
.readdir = test_readdir,
.open = test_open,
.read = test_read,
.write = test_write,
.truncate = test_truncate,
};
int main(int argc, char *argv[])
{
return fuse_main(argc, argv, &memfd_ops, NULL);
}
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