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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU LGPLv2.
See the file COPYING.LIB.
*/
#include "fuse_lowlevel.h"
#include "fuse_misc.h"
#include "fuse_kernel.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <semaphore.h>
#include <errno.h>
#include <sys/time.h>
#ifdef __MULTI_THREAD
/* Environment var controlling the thread stack size */
#define ENVNAME_THREAD_STACK "FUSE_THREAD_STACK"
struct fuse_worker {
struct fuse_worker *prev;
struct fuse_worker *next;
pthread_t thread_id;
size_t bufsize;
char *buf;
struct fuse_mt *mt;
};
struct fuse_mt {
pthread_mutex_t lock;
int numworker;
int numavail;
struct fuse_session *se;
struct fuse_chan *prevch;
struct fuse_worker main;
sem_t finish;
int exit;
int error;
};
static void list_add_worker(struct fuse_worker *w, struct fuse_worker *next)
{
struct fuse_worker *prev = next->prev;
w->next = next;
w->prev = prev;
prev->next = w;
next->prev = w;
}
static void list_del_worker(struct fuse_worker *w)
{
struct fuse_worker *prev = w->prev;
struct fuse_worker *next = w->next;
prev->next = next;
next->prev = prev;
}
#define PTHREAD_CANCEL_ENABLE 0
#define PTHREAD_CANCEL_DISABLE 1
static int fuse_start_thread(struct fuse_mt *mt);
static void *fuse_do_work(void *data)
{
struct fuse_worker *w = (struct fuse_worker *) data;
struct fuse_mt *mt = w->mt;
while (!fuse_session_exited(mt->se)) {
int isforget = 0;
struct fuse_chan *ch = mt->prevch;
int res;
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
res = fuse_chan_recv(&ch, w->buf, w->bufsize);
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
if (res == -EINTR)
continue;
if (res <= 0) {
if (res < 0) {
fuse_session_exit(mt->se);
mt->error = -1;
}
break;
}
pthread_mutex_lock(&mt->lock);
if (mt->exit) {
pthread_mutex_unlock(&mt->lock);
return NULL;
}
/*
* This disgusting hack is needed so that zillions of threads
* are not created on a burst of FORGET messages
*/
if (((struct fuse_in_header *) w->buf)->opcode == FUSE_FORGET)
isforget = 1;
if (!isforget)
mt->numavail--;
if (mt->numavail == 0)
fuse_start_thread(mt);
pthread_mutex_unlock(&mt->lock);
fuse_session_process(mt->se, w->buf, res, ch);
pthread_mutex_lock(&mt->lock);
if (!isforget)
mt->numavail++;
if (mt->numavail > 10) {
if (mt->exit) {
pthread_mutex_unlock(&mt->lock);
return NULL;
}
list_del_worker(w);
mt->numavail--;
mt->numworker--;
pthread_mutex_unlock(&mt->lock);
pthread_detach(w->thread_id);
free(w->buf);
free(w);
return NULL;
}
pthread_mutex_unlock(&mt->lock);
}
sem_post(&mt->finish);
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pause();
return NULL;
}
static int fuse_start_thread(struct fuse_mt *mt)
{
sigset_t oldset;
sigset_t newset;
int res;
pthread_attr_t attr;
char *stack_size;
struct fuse_worker *w = malloc(sizeof(struct fuse_worker));
if (!w) {
fprintf(stderr, "fuse: failed to allocate worker structure\n");
return -1;
}
memset(w, 0, sizeof(struct fuse_worker));
w->bufsize = fuse_chan_bufsize(mt->prevch);
w->buf = malloc(w->bufsize);
w->mt = mt;
if (!w->buf) {
fprintf(stderr, "fuse: failed to allocate read buffer\n");
free(w);
return -1;
}
/* Override default stack size */
pthread_attr_init(&attr);
stack_size = getenv(ENVNAME_THREAD_STACK);
if (stack_size && pthread_attr_setstacksize(&attr, atoi(stack_size)))
fprintf(stderr, "fuse: invalid stack size: %s\n", stack_size);
/* Disallow signal reception in worker threads */
sigemptyset(&newset);
sigaddset(&newset, SIGTERM);
sigaddset(&newset, SIGINT);
sigaddset(&newset, SIGHUP);
sigaddset(&newset, SIGQUIT);
pthread_sigmask(SIG_BLOCK, &newset, &oldset);
res = pthread_create(&w->thread_id, &attr, fuse_do_work, w);
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
pthread_attr_destroy(&attr);
if (res != 0) {
fprintf(stderr, "fuse: error creating thread: %s\n",
strerror(res));
free(w->buf);
free(w);
return -1;
}
list_add_worker(w, &mt->main);
mt->numavail ++;
mt->numworker ++;
return 0;
}
static void fuse_join_worker(struct fuse_mt *mt, struct fuse_worker *w)
{
pthread_join(w->thread_id, NULL);
pthread_mutex_lock(&mt->lock);
list_del_worker(w);
pthread_mutex_unlock(&mt->lock);
free(w->buf);
free(w);
}
int fuse_session_loop_mt(struct fuse_session *se)
{
int err;
struct fuse_mt mt;
struct fuse_worker *w;
memset(&mt, 0, sizeof(struct fuse_mt));
mt.se = se;
mt.prevch = fuse_session_next_chan(se, NULL);
mt.error = 0;
mt.numworker = 0;
mt.numavail = 0;
mt.main.thread_id = pthread_self();
mt.main.prev = mt.main.next = &mt.main;
sem_init(&mt.finish, 0, 0);
fuse_mutex_init(&mt.lock);
pthread_mutex_lock(&mt.lock);
err = fuse_start_thread(&mt);
pthread_mutex_unlock(&mt.lock);
if (!err) {
/* sem_wait() is interruptible */
while (!fuse_session_exited(se))
sem_wait(&mt.finish);
for (w = mt.main.next; w != &mt.main; w = w->next)
pthread_cancel(w->thread_id);
mt.exit = 1;
pthread_mutex_unlock(&mt.lock);
while (mt.main.next != &mt.main)
fuse_join_worker(&mt, mt.main.next);
err = mt.error;
}
pthread_mutex_destroy(&mt.lock);
sem_destroy(&mt.finish);
fuse_session_reset(se);
return err;
}
#endif
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