1 下载FUSE
GitHub地址：https://github.com/libfuse/libfuse
在FUSE的GitHub页面上下载最新Release版本libfuse 3.8.0 https://github.com/libfuse/libfuse/archive/fuse-3.8.0.tar.gz
2 编译安装FUSE
2.1 编译准备工作
推荐使用Meson和ninja来编译安装FUSE。
apt install ninja-build
apt install meson
2.2 Meson预处理
将下载的fuse压缩包解压到/opt/目录（此目录可自定义，推荐/opt/）。创建一个临时的build目录并且在build目录中执行Meson：
cd /opt/
tar zxvf libfuse-fuse-3.8.0.tar.gz
mv libfuse-fuse-3.8.0 libfuse
cd libfuse
mkdir build; cd build
成功后会看到以下提示：
➜ build meson ..
The Meson build system
Version: 0.45.1
Source dir: /opt/libfuse
Build dir: /opt/libfuse/build
Build type: native build
Project name: libfuse3
Native C compiler: cc (gcc 7.4.0 "cc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0")
Native C++ compiler: c++ (gcc 7.4.0 "c++ (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0")
Build machine cpu family: x86_64
Build machine cpu: x86_64
Checking for function "fork": YES
Checking for function "fstatat": YES
Checking for function "openat": YES
Checking for function "readlinkat": YES
Checking for function "pipe2": YES
Checking for function "splice": YES
Checking for function "vmsplice": YES
Checking for function "posix_fallocate": YES
Checking for function "fdatasync": YES
Checking for function "utimensat": YES
Checking for function "copy_file_range": YES
Checking for function "fallocate": YES
Checking for function "setxattr": YES
Checking for function "iconv": YES
Checking whether type "struct stat" has member "st_atim": YES
Checking whether type "struct stat" has member "st_atimespec": NO
Configuring config.h using configuration
Message: Compiler warns about unused result even when casting to void
Dependency threads found: YES
Library iconv found: NO
Library dl found: YES
Library rt found: YES
Found pkg-config: /usr/bin/pkg-config (0.29.1)
Native dependency udev found: YES 237
Program install_helper.sh found: YES (/opt/libfuse/util/install_helper.sh)
Build targets in project: 26
Found ninja-1.8.2 at /usr/bin/ninja
2.3 使用Ninja来build，test和 install libfuse
ninja
sudo python3 -m pytest test/
pip3 install pytest # 安装python3 的pytest模块
sudo ninja install
输出结果：
➜ build ninja
[66/66] Linking target example/passthrough_hp.
➜ build sudo ninja install
[0/1] Installing files.
Installing lib/libfuse3.so.3.8.0 to /usr/local/lib/x86_64-linux-gnu/libfuse3.so.3.8.0
Installing util/fusermount3 to /usr/local/bin/fusermount3
Installing util/mount.fuse3 to /usr/local/sbin/mount.fuse3
Installing fuse.h to /usr/local/include/fuse3
Installing fuse_common.h to /usr/local/include/fuse3
Installing fuse_lowlevel.h to /usr/local/include/fuse3
Installing fuse_opt.h to /usr/local/include/fuse3
Installing cuse_lowlevel.h to /usr/local/include/fuse3
Installing fuse_log.h to /usr/local/include/fuse3
Installing /opt/libfuse/doc/fusermount3.1 to /usr/local/share/man/man1
Installing /opt/libfuse/doc/mount.fuse3.8 to /usr/local/share/man/man8
Installing /opt/libfuse/build/meson-private/fuse3.pc to /usr/local/lib/x86_64-linux-gnu/pkgconfig
Running custom install script '/opt/libfuse/util/install_helper.sh /usr/local/etc /usr/local/bin /lib/udev/rules.d true'
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
update-rc.d: warning: stop runlevel arguments (0 6) do not match fuse3 Default-Stop values (none)
3 测试hello.c例程文件系统
FUSE的example目录下自带了许多测试文件系统，其中最简单文件系统hello.c使用了high-level API，我们以此来测试FUSE是否安装成功。
hello.c源码如下：
/*
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
*
* minimal example filesystem using high-level API
*
* Compile with:
*
* gcc -Wall hello.c `pkg-config fuse3 --cflags --libs` -o hello
*
* ## Source code ##
* \include hello.c
*/
#define FUSE_USE_VERSION 31
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <assert.h>
/*
* Command line options
*
* We can't set default values for the char* fields here because
* fuse_opt_parse would attempt to free() them when the user specifies
* different values on the command line.
*/
static struct options {
const char *filename;
const char *contents;
int show_help;
} options;
#define OPTION(t, p) \
{ t, offsetof(struct options, p), 1 }
static const struct fuse_opt option_spec[] = {
OPTION("--name=%s", filename),
OPTION("--contents=%s", contents),
OPTION("-h", show_help),
OPTION("--help", show_help),
FUSE_OPT_END
};
static void *hello_init(struct fuse_conn_info *conn,
struct fuse_config *cfg)
{
(void) conn;
cfg->kernel_cache = 1;
return NULL;
}
static int hello_getattr(const char *path, struct stat *stbuf,
struct fuse_file_info *fi)
{
(void) fi;
int res = 0;
memset(stbuf, 0, sizeof(struct stat));
if (strcmp(path, "/") == 0) {
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
} else if (strcmp(path+1, options.filename) == 0) {
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = strlen(options.contents);
} else
res = -ENOENT;
return res;
}
static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
off_t offset, struct fuse_file_info *fi,
enum fuse_readdir_flags flags)
{
(void) offset;
(void) fi;
(void) flags;
if (strcmp(path, "/") != 0)
return -ENOENT;
filler(buf, ".", NULL, 0, 0);
filler(buf, "..", NULL, 0, 0);
filler(buf, options.filename, NULL, 0, 0);
return 0;
}
static int hello_open(const char *path, struct fuse_file_info *fi)
{
if (strcmp(path+1, options.filename) != 0)
return -ENOENT;
if ((fi->flags & O_ACCMODE) != O_RDONLY)
return -EACCES;
return 0;
}
static int hello_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
size_t len;
(void) fi;
if(strcmp(path+1, options.filename) != 0)
return -ENOENT;
len = strlen(options.contents);
if (offset < len) {
if (offset + size > len)
size = len - offset;
memcpy(buf, options.contents + offset, size);
} else
size = 0;
return size;
}
static struct fuse_operations hello_oper = {
.init = hello_init,
.getattr = hello_getattr,
.readdir = hello_readdir,
.open = hello_open,
.read = hello_read,
};
static void show_help(const char *progname)
{
printf("usage: %s [options] <mountpoint>\n\n", progname);
printf("File-system specific options:\n"
" --name=<s> Name of the \"hello\" file\n"
" (default: \"hello\")\n"
" --contents=<s> Contents \"hello\" file\n"
" (default \"Hello, World!\\n\")\n"
"\n");
}
int main(int argc, char *argv[])
{
int ret;
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
/* Set defaults -- we have to use strdup so that
fuse_opt_parse can free the defaults if other
values are specified */
options.filename = strdup("hello");
options.contents = strdup("Hello World!\n");
/* Parse options */
if (fuse_opt_parse(&args, &options, option_spec, NULL) == -1)
return 1;
/* When --help is specified, first print our own file-system
specific help text, then signal fuse_main to show
additional help (by adding `--help` to the options again)
without usage: line (by setting argv[0] to the empty
string) */
if (options.show_help) {
show_help(argv[0]);
assert(fuse_opt_add_arg(&args, "--help") == 0);
args.argv[0][0] = '\0';
}
ret = fuse_main(args.argc, args.argv, &hello_oper, NULL);
fuse_opt_free_args(&args);
return ret;
}
从hello.c的注释中我们可以看到gcc编译方式：
gcc -Wall hello.c `pkg-config fuse3 --cflags --libs` -o hello
编译后执行后将hello文件系统挂载到test_dir目录上：
➜ example gcc -Wall hello.c `pkg-config fuse3 --cflags --libs` -o hello
➜ example mkdir test_dir
➜ example ./hello test_dir
./hello: error while loading shared libraries: libfuse3.so.3: cannot open shared object file: No such file or directory
出错原因是未配置ldconfig，以下是解决方式：
- 在/etc/ld.so.conf.d/目录下新建文件fuse.conf
vim /etc/ld.so.conf.d/fuse.conf - 写入fuse的安装路径
/usr/local/lib - 保存退出，执行ldconfig
ldconfig
重新挂载
➜ example ./hello test_dir
➜ example mount |grep test_dir
/root/Programming/4_fuse/example/hello on /root/Programming/4_fuse/example/test_dir type fuse.hello (rw,nosuid,nodev,relatime,user_id=0,group_id=0)
4 分析hello文件系统
待续。。。
