cuse_lowlevel.c
/*
CUSE: Character device in Userspace
Copyright (C) 2008 SUSE Linux Products GmbH
Copyright (C) 2008 Tejun Heo <teheo@suse.de>
This program can be distributed under the terms of the GNU LGPLv2.
See the file COPYING.LIB.
*/
#include "config.h"
#include "cuse_lowlevel.h"
#include "fuse_kernel.h"
#include "fuse_i.h"
#include "fuse_opt.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <errno.h>
#include <unistd.h>
struct cuse_data {
struct cuse_lowlevel_ops clop;
unsigned max_read;
unsigned dev_major;
unsigned dev_minor;
unsigned flags;
unsigned dev_info_len;
char dev_info[];
};
static struct cuse_lowlevel_ops *req_clop(fuse_req_t req)
{
return &req->se->cuse_data->clop;
}
static void cuse_fll_open(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->open(req, fi);
}
static void cuse_fll_read(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t off, struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->read(req, size, off, fi);
}
static void cuse_fll_write(fuse_req_t req, fuse_ino_t ino, const char *buf,
size_t size, off_t off, struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->write(req, buf, size, off, fi);
}
static void cuse_fll_flush(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->flush(req, fi);
}
static void cuse_fll_release(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->release(req, fi);
}
static void cuse_fll_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
struct fuse_file_info *fi)
{
(void)ino;
req_clop(req)->fsync(req, datasync, fi);
}
static void cuse_fll_ioctl(fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
struct fuse_file_info *fi, unsigned int flags,
const void *in_buf, size_t in_bufsz, size_t out_bufsz)
{
(void)ino;
req_clop(req)->ioctl(req, cmd, arg, fi, flags, in_buf, in_bufsz,
out_bufsz);
}
static void cuse_fll_poll(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi, struct fuse_pollhandle *ph)
{
(void)ino;
req_clop(req)->poll(req, fi, ph);
}
static size_t cuse_pack_info(int argc, const char **argv, char *buf)
{
size_t size = 0;
int i;
for (i = 0; i < argc; i++) {
size_t len;
len = strlen(argv[i]) + 1;
size += len;
if (buf) {
memcpy(buf, argv[i], len);
buf += len;
}
}
return size;
}
static struct cuse_data *cuse_prep_data(const struct cuse_info *ci,
const struct cuse_lowlevel_ops *clop)
{
struct cuse_data *cd;
size_t dev_info_len;
dev_info_len = cuse_pack_info(ci->dev_info_argc, ci->dev_info_argv,
NULL);
if (dev_info_len > CUSE_INIT_INFO_MAX) {
fprintf(stderr, "cuse: dev_info (%zu) too large, limit=%u\n",
dev_info_len, CUSE_INIT_INFO_MAX);
return NULL;
}
cd = calloc(1, sizeof(*cd) + dev_info_len);
if (!cd) {
fprintf(stderr, "cuse: failed to allocate cuse_data\n");
return NULL;
}
memcpy(&cd->clop, clop, sizeof(cd->clop));
cd->max_read = 131072;
cd->dev_major = ci->dev_major;
cd->dev_minor = ci->dev_minor;
cd->dev_info_len = dev_info_len;
cd->flags = ci->flags;
cuse_pack_info(ci->dev_info_argc, ci->dev_info_argv, cd->dev_info);
return cd;
}
struct fuse_session *cuse_lowlevel_new(struct fuse_args *args,
const struct cuse_info *ci,
const struct cuse_lowlevel_ops *clop,
void *userdata)
{
struct fuse_lowlevel_ops lop;
struct cuse_data *cd;
struct fuse_session *se;
cd = cuse_prep_data(ci, clop);
if (!cd)
return NULL;
memset(&lop, 0, sizeof(lop));
lop.init = clop->init;
lop.destroy = clop->destroy;
lop.open = clop->open ? cuse_fll_open : NULL;
lop.read = clop->read ? cuse_fll_read : NULL;
lop.write = clop->write ? cuse_fll_write : NULL;
lop.flush = clop->flush ? cuse_fll_flush : NULL;
lop.release = clop->release ? cuse_fll_release : NULL;
lop.fsync = clop->fsync ? cuse_fll_fsync : NULL;
lop.ioctl = clop->ioctl ? cuse_fll_ioctl : NULL;
lop.poll = clop->poll ? cuse_fll_poll : NULL;
se = fuse_session_new(args, &lop, sizeof(lop), userdata);
if (!se) {
free(cd);
return NULL;
}
se->cuse_data = cd;
return se;
}
static int cuse_reply_init(fuse_req_t req, struct cuse_init_out *arg,
char *dev_info, unsigned dev_info_len)
{
struct iovec iov[3];
iov[1].iov_base = arg;
iov[1].iov_len = sizeof(struct cuse_init_out);
iov[2].iov_base = dev_info;
iov[2].iov_len = dev_info_len;
return fuse_send_reply_iov_nofree(req, 0, iov, 3);
}
void cuse_lowlevel_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
struct fuse_init_in *arg = (struct fuse_init_in *) inarg;
struct cuse_init_out outarg;
struct fuse_session *se = req->se;
struct cuse_data *cd = se->cuse_data;
size_t bufsize = se->bufsize;
struct cuse_lowlevel_ops *clop = req_clop(req);
(void) nodeid;
if (se->debug) {
fprintf(stderr, "CUSE_INIT: %u.%u\n", arg->major, arg->minor);
fprintf(stderr, "flags=0x%08x\n", arg->flags);
}
se->conn.proto_major = arg->major;
se->conn.proto_minor = arg->minor;
se->conn.capable = 0;
se->conn.want = 0;
if (arg->major < 7) {
fprintf(stderr, "cuse: unsupported protocol version: %u.%u\n",
arg->major, arg->minor);
fuse_reply_err(req, EPROTO);
return;
}
if (bufsize < FUSE_MIN_READ_BUFFER) {
fprintf(stderr, "cuse: warning: buffer size too small: %zu\n",
bufsize);
bufsize = FUSE_MIN_READ_BUFFER;
}
bufsize -= 4096;
if (bufsize < se->conn.max_write)
se->conn.max_write = bufsize;
se->got_init = 1;
if (se->op.init)
se->op.init(se->userdata, &se->conn);
memset(&outarg, 0, sizeof(outarg));
outarg.major = FUSE_KERNEL_VERSION;
outarg.minor = FUSE_KERNEL_MINOR_VERSION;
outarg.flags = cd->flags;
outarg.max_read = cd->max_read;
outarg.max_write = se->conn.max_write;
outarg.dev_major = cd->dev_major;
outarg.dev_minor = cd->dev_minor;
if (se->debug) {
fprintf(stderr, " CUSE_INIT: %u.%u\n",
outarg.major, outarg.minor);
fprintf(stderr, " flags=0x%08x\n", outarg.flags);
fprintf(stderr, " max_read=0x%08x\n", outarg.max_read);
fprintf(stderr, " max_write=0x%08x\n", outarg.max_write);
fprintf(stderr, " dev_major=%u\n", outarg.dev_major);
fprintf(stderr, " dev_minor=%u\n", outarg.dev_minor);
fprintf(stderr, " dev_info: %.*s\n", cd->dev_info_len,
cd->dev_info);
}
cuse_reply_init(req, &outarg, cd->dev_info, cd->dev_info_len);
if (clop->init_done)
clop->init_done(se->userdata);
fuse_free_req(req);
}
struct fuse_session *cuse_lowlevel_setup(int argc, char *argv[],
const struct cuse_info *ci,
const struct cuse_lowlevel_ops *clop,
int *multithreaded, void *userdata)
{
const char *devname = "/dev/cuse";
static const struct fuse_opt kill_subtype_opts[] = {
FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_DISCARD),
FUSE_OPT_END
};
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
struct fuse_session *se;
struct fuse_cmdline_opts opts;
int fd;
int res;
if (fuse_parse_cmdline(&args, &opts) == -1)
return NULL;
*multithreaded = !opts.singlethread;
/* Remove subtype= option */
res = fuse_opt_parse(&args, NULL, kill_subtype_opts, NULL);
if (res == -1)
goto out1;
/*
* Make sure file descriptors 0, 1 and 2 are open, otherwise chaos
* would ensue.
*/
do {
fd = open("/dev/null", O_RDWR);
if (fd > 2)
close(fd);
} while (fd >= 0 && fd <= 2);
se = cuse_lowlevel_new(&args, ci, clop, userdata);
if (se == NULL)
goto out1;
fd = open(devname, O_RDWR);
if (fd == -1) {
if (errno == ENODEV || errno == ENOENT)
fprintf(stderr, "cuse: device not found, try 'modprobe cuse' first\n");
else
fprintf(stderr, "cuse: failed to open %s: %s\n",
devname, strerror(errno));
goto err_se;
}
se->fd = fd;
res = fuse_set_signal_handlers(se);
if (res == -1)
goto err_se;
res = fuse_daemonize(opts.foreground);
if (res == -1)
goto err_sig;
return se;
err_sig:
fuse_remove_signal_handlers(se);
err_se:
fuse_session_destroy(se);
out1:
free(opts.mountpoint);
fuse_opt_free_args(&args);
return NULL;
}
void cuse_lowlevel_teardown(struct fuse_session *se)
{
fuse_remove_signal_handlers(se);
fuse_session_destroy(se);
}
int cuse_lowlevel_main(int argc, char *argv[], const struct cuse_info *ci,
const struct cuse_lowlevel_ops *clop, void *userdata)
{
struct fuse_session *se;
int multithreaded;
int res;
se = cuse_lowlevel_setup(argc, argv, ci, clop, &multithreaded,
userdata);
if (se == NULL)
return 1;
if (multithreaded) {
struct fuse_loop_config config;
config.clone_fd = 0;
config.max_idle_threads = 10;
res = fuse_session_loop_mt_32(se, &config);
}
else
res = fuse_session_loop(se);
cuse_lowlevel_teardown(se);
if (res == -1)
return 1;
return 0;
}
fuse_session_destroy
void fuse_session_destroy(struct fuse_session *se)
Definition: fuse_lowlevel.c:2621
fuse_reply_err
int fuse_reply_err(fuse_req_t req, int err)
Definition: fuse_lowlevel.c:312
fuse_session_new
struct fuse_session * fuse_session_new(struct fuse_args *args, const struct fuse_lowlevel_ops *op, size_t op_size, void *userdata)
Definition: fuse_lowlevel.c:2809
fuse_session_loop
int fuse_session_loop(struct fuse_session *se)
Definition: fuse_loop.c:19
fuse_daemonize
int fuse_daemonize(int foreground)
Definition: helper.c:225
fuse_opt_parse
int fuse_opt_parse(struct fuse_args *args, void *data, const struct fuse_opt opts[], fuse_opt_proc_t proc)
Definition: fuse_opt.c:397
fuse_req_t
struct fuse_req * fuse_req_t
Definition: fuse_lowlevel.h:49
fuse_parse_cmdline
int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
Definition: helper.c:202
fuse_set_signal_handlers
int fuse_set_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:62
fuse_remove_signal_handlers
void fuse_remove_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:79
FUSE_OPT_KEY_DISCARD
#define FUSE_OPT_KEY_DISCARD
Definition: fuse_opt.h:153
fuse_file_info
Definition: fuse_common.h:37
fuse_loop_config
Definition: fuse_common.h:86
fuse_opt_free_args
void fuse_opt_free_args(struct fuse_args *args)
Definition: fuse_opt.c:33
fuse_opt.h
FUSE_OPT_KEY
#define FUSE_OPT_KEY(templ, key)
Definition: fuse_opt.h:98
FUSE_OPT_END
#define FUSE_OPT_END
Definition: fuse_opt.h:104
fuse_ino_t
uint64_t fuse_ino_t
Definition: fuse_lowlevel.h:46
fuse_lowlevel_ops
Definition: fuse_lowlevel.h:175
fuse_opt
Definition: fuse_opt.h:77
fuse_args
Definition: fuse_opt.h:109
FUSE_ARGS_INIT
#define FUSE_ARGS_INIT(argc, argv)
Definition: fuse_opt.h:123
fuse_loop_config::clone_fd
int clone_fd
Definition: fuse_common.h:91