/* $NetBSD: chan.c,v 1.1 2022/01/22 08:09:40 pho Exp $ */
/*
* Copyright (c) 2021 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if !defined(lint)
__RCSID("$NetBSD: chan.c,v 1.1 2022/01/22 08:09:40 pho Exp $");
#endif /* !lint */
#include <assert.h>
#include <err.h>
#include <fuse_internal.h>
#if defined(MULTITHREADED_REFUSE)
# include <pthread.h>
#endif
#include <stdlib.h>
#include <string.h>
/* The communication channel API is a part of the public interface of
* FUSE. However, it is actually an implementation detail and we can't
* really emulate its semantics. We only use it for implementing
* pre-3.0 fuse_mount(), i.e. the mount-before-new thingy.
*/
struct fuse_chan {
char* mountpoint;
struct fuse_args* args;
struct fuse* fuse;
bool is_to_be_destroyed;
};
struct refuse_chan_storage {
size_t n_alloc;
struct fuse_chan** vec;
};
#if defined(MULTITHREADED_REFUSE)
static pthread_mutex_t storage_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
static struct refuse_chan_storage storage;
struct fuse_chan* fuse_chan_new(const char* mountpoint, const struct fuse_args* args) {
struct fuse_chan* chan;
chan = calloc(1, sizeof(*chan));
if (!chan) {
warn("%s", __func__);
return NULL;
}
chan->mountpoint = strdup(mountpoint);
if (!chan->mountpoint) {
warn("%s", __func__);
free(chan);
return NULL;
}
chan->args = fuse_opt_deep_copy_args(args->argc, args->argv);
if (!chan->args) {
warn("%s", __func__);
free(chan->mountpoint);
free(chan);
return NULL;
}
return chan;
}
void
fuse_chan_destroy(struct fuse_chan* chan) {
free(chan->mountpoint);
fuse_opt_free_args(chan->args);
free(chan->args);
free(chan);
}
int
fuse_chan_stash(struct fuse_chan* chan) {
int idx;
#if defined(MULTITHREADED_REFUSE)
int rv;
rv = pthread_mutex_lock(&storage_mutex);
assert(rv == 0);
#endif
/* Find the first empty slot in the storage. */
for (idx = 0; idx < (int)storage.n_alloc; idx++) {
if (storage.vec[idx] == NULL) {
storage.vec[idx] = chan;
goto done;
}
}
/* Allocate more space */
storage.n_alloc = (storage.n_alloc + 8) * 2;
storage.vec = realloc(storage.vec, sizeof(struct fuse_chan*) * storage.n_alloc);
if (!storage.vec) {
warn("%s", __func__);
idx = -1;
goto done;
}
storage.vec[idx] = chan;
memset(&storage.vec[idx+1], 0, sizeof(struct fuse_chan*) * (storage.n_alloc - (size_t)idx - 1));
done:
#if defined(MULTITHREADED_REFUSE)
rv = pthread_mutex_unlock(&storage_mutex);
assert(rv == 0);
#endif
return idx;
}
/* Acquire a pointer to a stashed channel with a given index. */
struct fuse_chan* fuse_chan_peek(int idx) {
struct fuse_chan* chan = NULL;
#if defined(MULTITHREADED_REFUSE)
int rv;
rv = pthread_mutex_lock(&storage_mutex);
assert(rv == 0);
#endif
if (idx >= 0 && idx < (int)storage.n_alloc) {
chan = storage.vec[idx];
}
#if defined(MULTITHREADED_REFUSE)
rv = pthread_mutex_unlock(&storage_mutex);
assert(rv == 0);
#endif
return chan;
}
/* Like fuse_chan_peek() but also removes the channel from the
* storage. */
struct fuse_chan* fuse_chan_take(int idx) {
struct fuse_chan* chan = NULL;
#if defined(MULTITHREADED_REFUSE)
int rv;
rv = pthread_mutex_lock(&storage_mutex);
assert(rv == 0);
#endif
if (idx >= 0 && idx < (int)storage.n_alloc) {
chan = storage.vec[idx];
storage.vec[idx] = NULL;
}
#if defined(MULTITHREADED_REFUSE)
rv = pthread_mutex_unlock(&storage_mutex);
assert(rv == 0);
#endif
return chan;
}
/* Find the first stashed channel satisfying a given predicate in the
* storage, or NULL if no channels satisfy it. */
struct fuse_chan*
fuse_chan_find(bool (*pred)(struct fuse_chan*, void*),
int* found_idx, void* priv) {
int idx;
struct fuse_chan* chan = NULL;
#if defined(MULTITHREADED_REFUSE)
int rv;
rv = pthread_mutex_lock(&storage_mutex);
assert(rv == 0);
#endif
for (idx = 0; idx < (int)storage.n_alloc; idx++) {
if (storage.vec[idx] != NULL) {
if (pred(storage.vec[idx], priv)) {
chan = storage.vec[idx];
if (found_idx)
*found_idx = idx;
goto done;
}
}
}
done:
#if defined(MULTITHREADED_REFUSE)
rv = pthread_mutex_unlock(&storage_mutex);
assert(rv == 0);
#endif
return chan;
}
void
fuse_chan_set_fuse(struct fuse_chan* chan, struct fuse* fuse) {
chan->fuse = fuse;
}
void
fuse_chan_set_to_be_destroyed(struct fuse_chan* chan, bool is_to_be_destroyed) {
chan->is_to_be_destroyed = is_to_be_destroyed;
}
const char*
fuse_chan_mountpoint(const struct fuse_chan* chan) {
return chan->mountpoint;
}
struct fuse_args*
fuse_chan_args(struct fuse_chan* chan) {
return chan->args;
}
struct fuse*
fuse_chan_fuse(struct fuse_chan* chan) {
return chan->fuse;
}
bool
fuse_chan_is_to_be_destroyed(const struct fuse_chan* chan) {
return chan->is_to_be_destroyed;
}