fuse_lowlevel.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
 
  Implementation of (most of) the low-level FUSE API. The session loop
  functions are implemented in separate files.
 
  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB
*/
 
#define _GNU_SOURCE
 
#include "config.h"
#include "fuse_i.h"
#include "fuse_kernel.h"
#include "fuse_opt.h"
#include "fuse_misc.h"
#include "mount_util.h"
 
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include <sys/file.h>
 
#ifndef F_LINUX_SPECIFIC_BASE
#define F_LINUX_SPECIFIC_BASE       1024
#endif
#ifndef F_SETPIPE_SZ
#define F_SETPIPE_SZ    (F_LINUX_SPECIFIC_BASE + 7)
#endif
 
 
#define PARAM(inarg) (((char *)(inarg)) + sizeof(*(inarg)))
#define OFFSET_MAX 0x7fffffffffffffffLL
 
#define container_of(ptr, type, member) ({                              \
                        const typeof( ((type *)0)->member ) *__mptr = (ptr); \
                        (type *)( (char *)__mptr - offsetof(type,member) );})
 
struct fuse_pollhandle {
        uint64_t kh;
        struct fuse_session *se;
};
 
static size_t pagesize;
 
static __attribute__((constructor)) void fuse_ll_init_pagesize(void)
{
        pagesize = getpagesize();
}
 
static void convert_stat(const struct stat *stbuf, struct fuse_attr *attr)
{
        attr->ino       = stbuf->st_ino;
        attr->mode      = stbuf->st_mode;
        attr->nlink     = stbuf->st_nlink;
        attr->uid       = stbuf->st_uid;
        attr->gid       = stbuf->st_gid;
        attr->rdev      = stbuf->st_rdev;
        attr->size      = stbuf->st_size;
        attr->blksize   = stbuf->st_blksize;
        attr->blocks    = stbuf->st_blocks;
        attr->atime     = stbuf->st_atime;
        attr->mtime     = stbuf->st_mtime;
        attr->ctime     = stbuf->st_ctime;
        attr->atimensec = ST_ATIM_NSEC(stbuf);
        attr->mtimensec = ST_MTIM_NSEC(stbuf);
        attr->ctimensec = ST_CTIM_NSEC(stbuf);
}
 
static void convert_attr(const struct fuse_setattr_in *attr, struct stat *stbuf)
{
        stbuf->st_mode         = attr->mode;
        stbuf->st_uid          = attr->uid;
        stbuf->st_gid          = attr->gid;
        stbuf->st_size         = attr->size;
        stbuf->st_atime        = attr->atime;
        stbuf->st_mtime        = attr->mtime;
        stbuf->st_ctime        = attr->ctime;
        ST_ATIM_NSEC_SET(stbuf, attr->atimensec);
        ST_MTIM_NSEC_SET(stbuf, attr->mtimensec);
        ST_CTIM_NSEC_SET(stbuf, attr->ctimensec);
}
 
static  size_t iov_length(const struct iovec *iov, size_t count)
{
        size_t seg;
        size_t ret = 0;
 
        for (seg = 0; seg < count; seg++)
                ret += iov[seg].iov_len;
        return ret;
}
 
static void list_init_req(struct fuse_req *req)
{
        req->next = req;
        req->prev = req;
}
 
static void list_del_req(struct fuse_req *req)
{
        struct fuse_req *prev = req->prev;
        struct fuse_req *next = req->next;
        prev->next = next;
        next->prev = prev;
}
 
static void list_add_req(struct fuse_req *req, struct fuse_req *next)
{
        struct fuse_req *prev = next->prev;
        req->next = next;
        req->prev = prev;
        prev->next = req;
        next->prev = req;
}
 
static void destroy_req(fuse_req_t req)
{
        pthread_mutex_destroy(&req->lock);
        free(req);
}
 
void fuse_free_req(fuse_req_t req)
{
        int ctr;
        struct fuse_session *se = req->se;
 
        pthread_mutex_lock(&se->lock);
        req->u.ni.func = NULL;
        req->u.ni.data = NULL;
        list_del_req(req);
        ctr = --req->ctr;
        fuse_chan_put(req->ch);
        req->ch = NULL;
        pthread_mutex_unlock(&se->lock);
        if (!ctr)
                destroy_req(req);
}
 
static struct fuse_req *fuse_ll_alloc_req(struct fuse_session *se)
{
        struct fuse_req *req;
 
        req = (struct fuse_req *) calloc(1, sizeof(struct fuse_req));
        if (req == NULL) {
                fuse_log(FUSE_LOG_ERR, "fuse: failed to allocate request\n");
        } else {
                req->se = se;
                req->ctr = 1;
                list_init_req(req);
                pthread_mutex_init(&req->lock, NULL);
        }
 
        return req;
}
 
/* Send data. If *ch* is NULL, send via session master fd */
static int fuse_send_msg(struct fuse_session *se, struct fuse_chan *ch,
                         struct iovec *iov, int count)
{
        struct fuse_out_header *out = iov[0].iov_base;
 
        assert(se != NULL);
        out->len = iov_length(iov, count);
        if (se->debug) {
                if (out->unique == 0) {
                        fuse_log(FUSE_LOG_DEBUG, "NOTIFY: code=%d length=%u\n",
                                out->error, out->len);
                } else if (out->error) {
                        fuse_log(FUSE_LOG_DEBUG,
                                "   unique: %llu, error: %i (%s), outsize: %i\n",
                                (unsigned long long) out->unique, out->error,
                                strerror(-out->error), out->len);
                } else {
                        fuse_log(FUSE_LOG_DEBUG,
                                "   unique: %llu, success, outsize: %i\n",
                                (unsigned long long) out->unique, out->len);
                }
        }
 
        ssize_t res = writev(ch ? ch->fd : se->fd,
                             iov, count);
        int err = errno;
 
        if (res == -1) {
                /* ENOENT means the operation was interrupted */
                if (!fuse_session_exited(se) && err != ENOENT)
                        perror("fuse: writing device");
                return -err;
        }
 
        return 0;
}
 
 
int fuse_send_reply_iov_nofree(fuse_req_t req, int error, struct iovec *iov,
                               int count)
{
        struct fuse_out_header out;
 
        if (error <= -1000 || error > 0) {
                fuse_log(FUSE_LOG_ERR, "fuse: bad error value: %i\n",   error);
                error = -ERANGE;
        }
 
        out.unique = req->unique;
        out.error = error;
 
        iov[0].iov_base = &out;
        iov[0].iov_len = sizeof(struct fuse_out_header);
 
        return fuse_send_msg(req->se, req->ch, iov, count);
}
 
static int send_reply_iov(fuse_req_t req, int error, struct iovec *iov,
                          int count)
{
        int res;
 
        res = fuse_send_reply_iov_nofree(req, error, iov, count);
        fuse_free_req(req);
        return res;
}
 
static int send_reply(fuse_req_t req, int error, const void *arg,
                      size_t argsize)
{
        struct iovec iov[2];
        int count = 1;
        if (argsize) {
                iov[1].iov_base = (void *) arg;
                iov[1].iov_len = argsize;
                count++;
        }
        return send_reply_iov(req, error, iov, count);
}
 
int fuse_reply_iov(fuse_req_t req, const struct iovec *iov, int count)
{
        int res;
        struct iovec *padded_iov;
 
        padded_iov = malloc((count + 1) * sizeof(struct iovec));
        if (padded_iov == NULL)
                return fuse_reply_err(req, ENOMEM);
 
        memcpy(padded_iov + 1, iov, count * sizeof(struct iovec));
        count++;
 
        res = send_reply_iov(req, 0, padded_iov, count);
        free(padded_iov);
 
        return res;
}
 
 
/* `buf` is allowed to be empty so that the proper size may be
   allocated by the caller */
size_t fuse_add_direntry(fuse_req_t req, char *buf, size_t bufsize,
                         const char *name, const struct stat *stbuf, off_t off)
{
        (void)req;
        size_t namelen;
        size_t entlen;
        size_t entlen_padded;
        struct fuse_dirent *dirent;
 
        namelen = strlen(name);
        entlen = FUSE_NAME_OFFSET + namelen;
        entlen_padded = FUSE_DIRENT_ALIGN(entlen);
 
        if ((buf == NULL) || (entlen_padded > bufsize))
          return entlen_padded;
 
        dirent = (struct fuse_dirent*) buf;
        dirent->ino = stbuf->st_ino;
        dirent->off = off;
        dirent->namelen = namelen;
        dirent->type = (stbuf->st_mode & S_IFMT) >> 12;
        memcpy(dirent->name, name, namelen);
        memset(dirent->name + namelen, 0, entlen_padded - entlen);
 
        return entlen_padded;
}
 
static void convert_statfs(const struct statvfs *stbuf,
                           struct fuse_kstatfs *kstatfs)
{
        kstatfs->bsize   = stbuf->f_bsize;
        kstatfs->frsize  = stbuf->f_frsize;
        kstatfs->blocks  = stbuf->f_blocks;
        kstatfs->bfree   = stbuf->f_bfree;
        kstatfs->bavail  = stbuf->f_bavail;
        kstatfs->files   = stbuf->f_files;
        kstatfs->ffree   = stbuf->f_ffree;
        kstatfs->namelen = stbuf->f_namemax;
}
 
static int send_reply_ok(fuse_req_t req, const void *arg, size_t argsize)
{
        return send_reply(req, 0, arg, argsize);
}
 
int fuse_reply_err(fuse_req_t req, int err)
{
        return send_reply(req, -err, NULL, 0);
}
 
void fuse_reply_none(fuse_req_t req)
{
        fuse_free_req(req);
}
 
static unsigned long calc_timeout_sec(double t)
{
        if (t > (double) ULONG_MAX)
                return ULONG_MAX;
        else if (t < 0.0)
                return 0;
        else
                return (unsigned long) t;
}
 
static unsigned int calc_timeout_nsec(double t)
{
        double f = t - (double) calc_timeout_sec(t);
        if (f < 0.0)
                return 0;
        else if (f >= 0.999999999)
                return 999999999;
        else
                return (unsigned int) (f * 1.0e9);
}
 
static void fill_entry(struct fuse_entry_out *arg,
                       const struct fuse_entry_param *e)
{
        arg->nodeid = e->ino;
        arg->generation = e->generation;
        arg->entry_valid = calc_timeout_sec(e->entry_timeout);
        arg->entry_valid_nsec = calc_timeout_nsec(e->entry_timeout);
        arg->attr_valid = calc_timeout_sec(e->attr_timeout);
        arg->attr_valid_nsec = calc_timeout_nsec(e->attr_timeout);
        convert_stat(&e->attr, &arg->attr);
}
 
/* `buf` is allowed to be empty so that the proper size may be
   allocated by the caller */
size_t fuse_add_direntry_plus(fuse_req_t req, char *buf, size_t bufsize,
                              const char *name,
                              const struct fuse_entry_param *e, off_t off)
{
        (void)req;
        size_t namelen;
        size_t entlen;
        size_t entlen_padded;
 
        namelen = strlen(name);
        entlen = FUSE_NAME_OFFSET_DIRENTPLUS + namelen;
        entlen_padded = FUSE_DIRENT_ALIGN(entlen);
        if ((buf == NULL) || (entlen_padded > bufsize))
          return entlen_padded;
 
        struct fuse_direntplus *dp = (struct fuse_direntplus *) buf;
        memset(&dp->entry_out, 0, sizeof(dp->entry_out));
        fill_entry(&dp->entry_out, e);
 
        struct fuse_dirent *dirent = &dp->dirent;
        dirent->ino = e->attr.st_ino;
        dirent->off = off;
        dirent->namelen = namelen;
        dirent->type = (e->attr.st_mode & S_IFMT) >> 12;
        memcpy(dirent->name, name, namelen);
        memset(dirent->name + namelen, 0, entlen_padded - entlen);
 
        return entlen_padded;
}
 
static void fill_open(struct fuse_open_out *arg,
                      const struct fuse_file_info *f)
{
        arg->fh = f->fh;
        if (f->direct_io)
                arg->open_flags |= FOPEN_DIRECT_IO;
        if (f->keep_cache)
                arg->open_flags |= FOPEN_KEEP_CACHE;
        if (f->cache_readdir)
                arg->open_flags |= FOPEN_CACHE_DIR;
        if (f->nonseekable)
                arg->open_flags |= FOPEN_NONSEEKABLE;
}
 
int fuse_reply_entry(fuse_req_t req, const struct fuse_entry_param *e)
{
        struct fuse_entry_out arg;
        size_t size = req->se->conn.proto_minor < 9 ?
                FUSE_COMPAT_ENTRY_OUT_SIZE : sizeof(arg);
 
        /* before ABI 7.4 e->ino == 0 was invalid, only ENOENT meant
           negative entry */
        if (!e->ino && req->se->conn.proto_minor < 4)
                return fuse_reply_err(req, ENOENT);
 
        memset(&arg, 0, sizeof(arg));
        fill_entry(&arg, e);
        return send_reply_ok(req, &arg, size);
}
 
int fuse_reply_create(fuse_req_t req, const struct fuse_entry_param *e,
                      const struct fuse_file_info *f)
{
        char buf[sizeof(struct fuse_entry_out) + sizeof(struct fuse_open_out)];
        size_t entrysize = req->se->conn.proto_minor < 9 ?
                FUSE_COMPAT_ENTRY_OUT_SIZE : sizeof(struct fuse_entry_out);
        struct fuse_entry_out *earg = (struct fuse_entry_out *) buf;
        struct fuse_open_out *oarg = (struct fuse_open_out *) (buf + entrysize);
 
        memset(buf, 0, sizeof(buf));
        fill_entry(earg, e);
        fill_open(oarg, f);
        return send_reply_ok(req, buf,
                             entrysize + sizeof(struct fuse_open_out));
}
 
int fuse_reply_attr(fuse_req_t req, const struct stat *attr,
                    double attr_timeout)
{
        struct fuse_attr_out arg;
        size_t size = req->se->conn.proto_minor < 9 ?
                FUSE_COMPAT_ATTR_OUT_SIZE : sizeof(arg);
 
        memset(&arg, 0, sizeof(arg));
        arg.attr_valid = calc_timeout_sec(attr_timeout);
        arg.attr_valid_nsec = calc_timeout_nsec(attr_timeout);
        convert_stat(attr, &arg.attr);
 
        return send_reply_ok(req, &arg, size);
}
 
int fuse_reply_readlink(fuse_req_t req, const char *linkname)
{
        return send_reply_ok(req, linkname, strlen(linkname));
}
 
int fuse_reply_open(fuse_req_t req, const struct fuse_file_info *f)
{
        struct fuse_open_out arg;
 
        memset(&arg, 0, sizeof(arg));
        fill_open(&arg, f);
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
int fuse_reply_write(fuse_req_t req, size_t count)
{
        struct fuse_write_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.size = count;
 
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
int fuse_reply_buf(fuse_req_t req, const char *buf, size_t size)
{
        return send_reply_ok(req, buf, size);
}
 
static int fuse_send_data_iov_fallback(struct fuse_session *se,
                                       struct fuse_chan *ch,
                                       struct iovec *iov, int iov_count,
                                       struct fuse_bufvec *buf,
                                       size_t len)
{
        struct fuse_bufvec mem_buf = FUSE_BUFVEC_INIT(len);
        void *mbuf;
        int res;
 
        /* Optimize common case */
        if (buf->count == 1 && buf->idx == 0 && buf->off == 0 &&
            !(buf->buf[0].flags & FUSE_BUF_IS_FD)) {
                /* FIXME: also avoid memory copy if there are multiple buffers
                   but none of them contain an fd */
 
                iov[iov_count].iov_base = buf->buf[0].mem;
                iov[iov_count].iov_len = len;
                iov_count++;
                return fuse_send_msg(se, ch, iov, iov_count);
        }
 
        res = posix_memalign(&mbuf, pagesize, len);
        if (res != 0)
                return res;
 
        mem_buf.buf[0].mem = mbuf;
        res = fuse_buf_copy(&mem_buf, buf, 0);
        if (res < 0) {
                free(mbuf);
                return -res;
        }
        len = res;
 
        iov[iov_count].iov_base = mbuf;
        iov[iov_count].iov_len = len;
        iov_count++;
        res = fuse_send_msg(se, ch, iov, iov_count);
        free(mbuf);
 
        return res;
}
 
struct fuse_ll_pipe {
        size_t size;
        int can_grow;
        int pipe[2];
};
 
static void fuse_ll_pipe_free(struct fuse_ll_pipe *llp)
{
        close(llp->pipe[0]);
        close(llp->pipe[1]);
        free(llp);
}
 
#ifdef HAVE_SPLICE
#if !defined(HAVE_PIPE2) || !defined(O_CLOEXEC)
static int fuse_pipe(int fds[2])
{
        int rv = pipe(fds);
 
        if (rv == -1)
                return rv;
 
        if (fcntl(fds[0], F_SETFL, O_NONBLOCK) == -1 ||
            fcntl(fds[1], F_SETFL, O_NONBLOCK) == -1 ||
            fcntl(fds[0], F_SETFD, FD_CLOEXEC) == -1 ||
            fcntl(fds[1], F_SETFD, FD_CLOEXEC) == -1) {
                close(fds[0]);
                close(fds[1]);
                rv = -1;
        }
        return rv;
}
#else
static int fuse_pipe(int fds[2])
{
        return pipe2(fds, O_CLOEXEC | O_NONBLOCK);
}
#endif
 
static struct fuse_ll_pipe *fuse_ll_get_pipe(struct fuse_session *se)
{
        struct fuse_ll_pipe *llp = pthread_getspecific(se->pipe_key);
        if (llp == NULL) {
                int res;
 
                llp = malloc(sizeof(struct fuse_ll_pipe));
                if (llp == NULL)
                        return NULL;
 
                res = fuse_pipe(llp->pipe);
                if (res == -1) {
                        free(llp);
                        return NULL;
                }
 
                /*
                 *the default size is 16 pages on linux
                 */
                llp->size = pagesize * 16;
                llp->can_grow = 1;
 
                pthread_setspecific(se->pipe_key, llp);
        }
 
        return llp;
}
#endif
 
static void fuse_ll_clear_pipe(struct fuse_session *se)
{
        struct fuse_ll_pipe *llp = pthread_getspecific(se->pipe_key);
        if (llp) {
                pthread_setspecific(se->pipe_key, NULL);
                fuse_ll_pipe_free(llp);
        }
}
 
#if defined(HAVE_SPLICE) && defined(HAVE_VMSPLICE)
static int read_back(int fd, char *buf, size_t len)
{
        int res;
 
        res = read(fd, buf, len);
        if (res == -1) {
                fuse_log(FUSE_LOG_ERR, "fuse: internal error: failed to read back from pipe: %s\n", strerror(errno));
                return -EIO;
        }
        if (res != len) {
                fuse_log(FUSE_LOG_ERR, "fuse: internal error: short read back from pipe: %i from %zi\n", res, len);
                return -EIO;
        }
        return 0;
}
 
static int grow_pipe_to_max(int pipefd)
{
        int max;
        int res;
        int maxfd;
        char buf[32];
 
        maxfd = open("/proc/sys/fs/pipe-max-size", O_RDONLY);
        if (maxfd < 0)
                return -errno;
 
        res = read(maxfd, buf, sizeof(buf) - 1);
        if (res < 0) {
                int saved_errno;
 
                saved_errno = errno;
                close(maxfd);
                return -saved_errno;
        }
        close(maxfd);
        buf[res] = '\0';
 
        max = atoi(buf);
        res = fcntl(pipefd, F_SETPIPE_SZ, max);
        if (res < 0)
                return -errno;
        return max;
}
 
static int fuse_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
                               struct iovec *iov, int iov_count,
                               struct fuse_bufvec *buf, unsigned int flags)
{
        int res;
        size_t len = fuse_buf_size(buf);
        struct fuse_out_header *out = iov[0].iov_base;
        struct fuse_ll_pipe *llp;
        int splice_flags;
        size_t pipesize;
        size_t total_buf_size;
        size_t idx;
        size_t headerlen;
        struct fuse_bufvec pipe_buf = FUSE_BUFVEC_INIT(len);
 
        if (se->broken_splice_nonblock)
                goto fallback;
 
        if (flags & FUSE_BUF_NO_SPLICE)
                goto fallback;
 
        total_buf_size = 0;
        for (idx = buf->idx; idx < buf->count; idx++) {
                total_buf_size += buf->buf[idx].size;
                if (idx == buf->idx)
                        total_buf_size -= buf->off;
        }
        if (total_buf_size < 2 * pagesize)
                goto fallback;
 
        if (se->conn.proto_minor < 14 ||
            !(se->conn.want & FUSE_CAP_SPLICE_WRITE))
                goto fallback;
 
        llp = fuse_ll_get_pipe(se);
        if (llp == NULL)
                goto fallback;
 
 
        headerlen = iov_length(iov, iov_count);
 
        out->len = headerlen + len;
 
        /*
         * Heuristic for the required pipe size, does not work if the
         * source contains less than page size fragments
         */
        pipesize = pagesize * (iov_count + buf->count + 1) + out->len;
 
        if (llp->size < pipesize) {
                if (llp->can_grow) {
                        res = fcntl(llp->pipe[0], F_SETPIPE_SZ, pipesize);
                        if (res == -1) {
                                res = grow_pipe_to_max(llp->pipe[0]);
                                if (res > 0)
                                        llp->size = res;
                                llp->can_grow = 0;
                                goto fallback;
                        }
                        llp->size = res;
                }
                if (llp->size < pipesize)
                        goto fallback;
        }
 
 
        res = vmsplice(llp->pipe[1], iov, iov_count, SPLICE_F_NONBLOCK);
        if (res == -1)
                goto fallback;
 
        if (res != headerlen) {
                res = -EIO;
                fuse_log(FUSE_LOG_ERR, "fuse: short vmsplice to pipe: %u/%zu\n", res,
                        headerlen);
                goto clear_pipe;
        }
 
        pipe_buf.buf[0].flags = FUSE_BUF_IS_FD;
        pipe_buf.buf[0].fd = llp->pipe[1];
 
        res = fuse_buf_copy(&pipe_buf, buf,
                            FUSE_BUF_FORCE_SPLICE | FUSE_BUF_SPLICE_NONBLOCK);
        if (res < 0) {
                if (res == -EAGAIN || res == -EINVAL) {
                        /*
                         * Should only get EAGAIN on kernels with
                         * broken SPLICE_F_NONBLOCK support (<=
                         * 2.6.35) where this error or a short read is
                         * returned even if the pipe itself is not
                         * full
                         *
                         * EINVAL might mean that splice can't handle
                         * this combination of input and output.
                         */
                        if (res == -EAGAIN)
                                se->broken_splice_nonblock = 1;
 
                        pthread_setspecific(se->pipe_key, NULL);
                        fuse_ll_pipe_free(llp);
                        goto fallback;
                }
                res = -res;
                goto clear_pipe;
        }
 
        if (res != 0 && res < len) {
                struct fuse_bufvec mem_buf = FUSE_BUFVEC_INIT(len);
                void *mbuf;
                size_t now_len = res;
                /*
                 * For regular files a short count is either
                 *  1) due to EOF, or
                 *  2) because of broken SPLICE_F_NONBLOCK (see above)
                 *
                 * For other inputs it's possible that we overflowed
                 * the pipe because of small buffer fragments.
                 */
 
                res = posix_memalign(&mbuf, pagesize, len);
                if (res != 0)
                        goto clear_pipe;
 
                mem_buf.buf[0].mem = mbuf;
                mem_buf.off = now_len;
                res = fuse_buf_copy(&mem_buf, buf, 0);
                if (res > 0) {
                        char *tmpbuf;
                        size_t extra_len = res;
                        /*
                         * Trickiest case: got more data.  Need to get
                         * back the data from the pipe and then fall
                         * back to regular write.
                         */
                        tmpbuf = malloc(headerlen);
                        if (tmpbuf == NULL) {
                                free(mbuf);
                                res = ENOMEM;
                                goto clear_pipe;
                        }
                        res = read_back(llp->pipe[0], tmpbuf, headerlen);
                        free(tmpbuf);
                        if (res != 0) {
                                free(mbuf);
                                goto clear_pipe;
                        }
                        res = read_back(llp->pipe[0], mbuf, now_len);
                        if (res != 0) {
                                free(mbuf);
                                goto clear_pipe;
                        }
                        len = now_len + extra_len;
                        iov[iov_count].iov_base = mbuf;
                        iov[iov_count].iov_len = len;
                        iov_count++;
                        res = fuse_send_msg(se, ch, iov, iov_count);
                        free(mbuf);
                        return res;
                }
                free(mbuf);
                res = now_len;
        }
        len = res;
        out->len = headerlen + len;
 
        if (se->debug) {
                fuse_log(FUSE_LOG_DEBUG,
                        "   unique: %llu, success, outsize: %i (splice)\n",
                        (unsigned long long) out->unique, out->len);
        }
 
        splice_flags = 0;
        if ((flags & FUSE_BUF_SPLICE_MOVE) &&
            (se->conn.want & FUSE_CAP_SPLICE_MOVE))
                splice_flags |= SPLICE_F_MOVE;
 
        res = splice(llp->pipe[0], NULL, ch ? ch->fd : se->fd,
                     NULL, out->len, splice_flags);
        if (res == -1) {
                res = -errno;
                perror("fuse: splice from pipe");
                goto clear_pipe;
        }
        if (res != out->len) {
                res = -EIO;
                fuse_log(FUSE_LOG_ERR, "fuse: short splice from pipe: %u/%u\n",
                        res, out->len);
                goto clear_pipe;
        }
        return 0;
 
clear_pipe:
        fuse_ll_clear_pipe(se);
        return res;
 
fallback:
        return fuse_send_data_iov_fallback(se, ch, iov, iov_count, buf, len);
}
#else
static int fuse_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
                               struct iovec *iov, int iov_count,
                               struct fuse_bufvec *buf, unsigned int flags)
{
        size_t len = fuse_buf_size(buf);
        (void) flags;
 
        return fuse_send_data_iov_fallback(se, ch, iov, iov_count, buf, len);
}
#endif
 
int fuse_reply_data(fuse_req_t req, struct fuse_bufvec *bufv,
                    enum fuse_buf_copy_flags flags)
{
        struct iovec iov[2];
        struct fuse_out_header out;
        int res;
 
        iov[0].iov_base = &out;
        iov[0].iov_len = sizeof(struct fuse_out_header);
 
        out.unique = req->unique;
        out.error = 0;
 
        res = fuse_send_data_iov(req->se, req->ch, iov, 1, bufv, flags);
        if (res <= 0) {
                fuse_free_req(req);
                return res;
        } else {
                return fuse_reply_err(req, res);
        }
}
 
int fuse_reply_statfs(fuse_req_t req, const struct statvfs *stbuf)
{
        struct fuse_statfs_out arg;
        size_t size = req->se->conn.proto_minor < 4 ?
                FUSE_COMPAT_STATFS_SIZE : sizeof(arg);
 
        memset(&arg, 0, sizeof(arg));
        convert_statfs(stbuf, &arg.st);
 
        return send_reply_ok(req, &arg, size);
}
 
int fuse_reply_xattr(fuse_req_t req, size_t count)
{
        struct fuse_getxattr_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.size = count;
 
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
int fuse_reply_lock(fuse_req_t req, const struct flock *lock)
{
        struct fuse_lk_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.lk.type = lock->l_type;
        if (lock->l_type != F_UNLCK) {
                arg.lk.start = lock->l_start;
                if (lock->l_len == 0)
                        arg.lk.end = OFFSET_MAX;
                else
                        arg.lk.end = lock->l_start + lock->l_len - 1;
        }
        arg.lk.pid = lock->l_pid;
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
int fuse_reply_bmap(fuse_req_t req, uint64_t idx)
{
        struct fuse_bmap_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.block = idx;
 
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
static struct fuse_ioctl_iovec *fuse_ioctl_iovec_copy(const struct iovec *iov,
                                                      size_t count)
{
        struct fuse_ioctl_iovec *fiov;
        size_t i;
 
        fiov = malloc(sizeof(fiov[0]) * count);
        if (!fiov)
                return NULL;
 
        for (i = 0; i < count; i++) {
                fiov[i].base = (uintptr_t) iov[i].iov_base;
                fiov[i].len = iov[i].iov_len;
        }
 
        return fiov;
}
 
int fuse_reply_ioctl_retry(fuse_req_t req,
                           const struct iovec *in_iov, size_t in_count,
                           const struct iovec *out_iov, size_t out_count)
{
        struct fuse_ioctl_out arg;
        struct fuse_ioctl_iovec *in_fiov = NULL;
        struct fuse_ioctl_iovec *out_fiov = NULL;
        struct iovec iov[4];
        size_t count = 1;
        int res;
 
        memset(&arg, 0, sizeof(arg));
        arg.flags |= FUSE_IOCTL_RETRY;
        arg.in_iovs = in_count;
        arg.out_iovs = out_count;
        iov[count].iov_base = &arg;
        iov[count].iov_len = sizeof(arg);
        count++;
 
        if (req->se->conn.proto_minor < 16) {
                if (in_count) {
                        iov[count].iov_base = (void *)in_iov;
                        iov[count].iov_len = sizeof(in_iov[0]) * in_count;
                        count++;
                }
 
                if (out_count) {
                        iov[count].iov_base = (void *)out_iov;
                        iov[count].iov_len = sizeof(out_iov[0]) * out_count;
                        count++;
                }
        } else {
                /* Can't handle non-compat 64bit ioctls on 32bit */
                if (sizeof(void *) == 4 && req->ioctl_64bit) {
                        res = fuse_reply_err(req, EINVAL);
                        goto out;
                }
 
                if (in_count) {
                        in_fiov = fuse_ioctl_iovec_copy(in_iov, in_count);
                        if (!in_fiov)
                                goto enomem;
 
                        iov[count].iov_base = (void *)in_fiov;
                        iov[count].iov_len = sizeof(in_fiov[0]) * in_count;
                        count++;
                }
                if (out_count) {
                        out_fiov = fuse_ioctl_iovec_copy(out_iov, out_count);
                        if (!out_fiov)
                                goto enomem;
 
                        iov[count].iov_base = (void *)out_fiov;
                        iov[count].iov_len = sizeof(out_fiov[0]) * out_count;
                        count++;
                }
        }
 
        res = send_reply_iov(req, 0, iov, count);
out:
        free(in_fiov);
        free(out_fiov);
 
        return res;
 
enomem:
        res = fuse_reply_err(req, ENOMEM);
        goto out;
}
 
int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, size_t size)
{
        struct fuse_ioctl_out arg;
        struct iovec iov[3];
        size_t count = 1;
 
        memset(&arg, 0, sizeof(arg));
        arg.result = result;
        iov[count].iov_base = &arg;
        iov[count].iov_len = sizeof(arg);
        count++;
 
        if (size) {
                iov[count].iov_base = (char *) buf;
                iov[count].iov_len = size;
                count++;
        }
 
        return send_reply_iov(req, 0, iov, count);
}
 
int fuse_reply_ioctl_iov(fuse_req_t req, int result, const struct iovec *iov,
                         int count)
{
        struct iovec *padded_iov;
        struct fuse_ioctl_out arg;
        int res;
 
        padded_iov = malloc((count + 2) * sizeof(struct iovec));
        if (padded_iov == NULL)
                return fuse_reply_err(req, ENOMEM);
 
        memset(&arg, 0, sizeof(arg));
        arg.result = result;
        padded_iov[1].iov_base = &arg;
        padded_iov[1].iov_len = sizeof(arg);
 
        memcpy(&padded_iov[2], iov, count * sizeof(struct iovec));
 
        res = send_reply_iov(req, 0, padded_iov, count + 2);
        free(padded_iov);
 
        return res;
}
 
int fuse_reply_poll(fuse_req_t req, unsigned revents)
{
        struct fuse_poll_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.revents = revents;
 
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
int fuse_reply_lseek(fuse_req_t req, off_t off)
{
        struct fuse_lseek_out arg;
 
        memset(&arg, 0, sizeof(arg));
        arg.offset = off;
 
        return send_reply_ok(req, &arg, sizeof(arg));
}
 
static void do_lookup(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        char *name = (char *) inarg;
 
        if (req->se->op.lookup)
                req->se->op.lookup(req, nodeid, name);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_forget(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_forget_in *arg = (struct fuse_forget_in *) inarg;
 
        if (req->se->op.forget)
                req->se->op.forget(req, nodeid, arg->nlookup);
        else
                fuse_reply_none(req);
}
 
static void do_batch_forget(fuse_req_t req, fuse_ino_t nodeid,
                            const void *inarg)
{
        struct fuse_batch_forget_in *arg = (void *) inarg;
        struct fuse_forget_one *param = (void *) PARAM(arg);
        unsigned int i;
 
        (void) nodeid;
 
        if (req->se->op.forget_multi) {
                req->se->op.forget_multi(req, arg->count,
                                     (struct fuse_forget_data *) param);
        } else if (req->se->op.forget) {
                for (i = 0; i < arg->count; i++) {
                        struct fuse_forget_one *forget = &param[i];
                        struct fuse_req *dummy_req;
 
                        dummy_req = fuse_ll_alloc_req(req->se);
                        if (dummy_req == NULL)
                                break;
 
                        dummy_req->unique = req->unique;
                        dummy_req->ctx = req->ctx;
                        dummy_req->ch = NULL;
 
                        req->se->op.forget(dummy_req, forget->nodeid,
                                          forget->nlookup);
                }
                fuse_reply_none(req);
        } else {
                fuse_reply_none(req);
        }
}
 
static void do_getattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_file_info *fip = NULL;
        struct fuse_file_info fi;
 
        if (req->se->conn.proto_minor >= 9) {
                struct fuse_getattr_in *arg = (struct fuse_getattr_in *) inarg;
 
                if (arg->getattr_flags & FUSE_GETATTR_FH) {
                        memset(&fi, 0, sizeof(fi));
                        fi.fh = arg->fh;
                        fip = &fi;
                }
        }
 
        if (req->se->op.getattr)
                req->se->op.getattr(req, nodeid, fip);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_setattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_setattr_in *arg = (struct fuse_setattr_in *) inarg;
 
        if (req->se->op.setattr) {
                struct fuse_file_info *fi = NULL;
                struct fuse_file_info fi_store;
                struct stat stbuf;
                memset(&stbuf, 0, sizeof(stbuf));
                convert_attr(arg, &stbuf);
                if (arg->valid & FATTR_FH) {
                        arg->valid &= ~FATTR_FH;
                        memset(&fi_store, 0, sizeof(fi_store));
                        fi = &fi_store;
                        fi->fh = arg->fh;
                }
                arg->valid &=
                        FUSE_SET_ATTR_MODE      |
                        FUSE_SET_ATTR_UID       |
                        FUSE_SET_ATTR_GID       |
                        FUSE_SET_ATTR_SIZE      |
                        FUSE_SET_ATTR_ATIME     |
                        FUSE_SET_ATTR_MTIME     |
                        FUSE_SET_ATTR_ATIME_NOW |
                        FUSE_SET_ATTR_MTIME_NOW |
                        FUSE_SET_ATTR_CTIME;
 
                req->se->op.setattr(req, nodeid, &stbuf, arg->valid, fi);
        } else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_access(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_access_in *arg = (struct fuse_access_in *) inarg;
 
        if (req->se->op.access)
                req->se->op.access(req, nodeid, arg->mask);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_readlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        (void) inarg;
 
        if (req->se->op.readlink)
                req->se->op.readlink(req, nodeid);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_mknod(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_mknod_in *arg = (struct fuse_mknod_in *) inarg;
        char *name = PARAM(arg);
 
        if (req->se->conn.proto_minor >= 12)
                req->ctx.umask = arg->umask;
        else
                name = (char *) inarg + FUSE_COMPAT_MKNOD_IN_SIZE;
 
        if (req->se->op.mknod)
                req->se->op.mknod(req, nodeid, name, arg->mode, arg->rdev);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_mkdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_mkdir_in *arg = (struct fuse_mkdir_in *) inarg;
 
        if (req->se->conn.proto_minor >= 12)
                req->ctx.umask = arg->umask;
 
        if (req->se->op.mkdir)
                req->se->op.mkdir(req, nodeid, PARAM(arg), arg->mode);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_unlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        char *name = (char *) inarg;
 
        if (req->se->op.unlink)
                req->se->op.unlink(req, nodeid, name);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_rmdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        char *name = (char *) inarg;
 
        if (req->se->op.rmdir)
                req->se->op.rmdir(req, nodeid, name);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_symlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        char *name = (char *) inarg;
        char *linkname = ((char *) inarg) + strlen((char *) inarg) + 1;
 
        if (req->se->op.symlink)
                req->se->op.symlink(req, linkname, nodeid, name);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_rename(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_rename_in *arg = (struct fuse_rename_in *) inarg;
        char *oldname = PARAM(arg);
        char *newname = oldname + strlen(oldname) + 1;
 
        if (req->se->op.rename)
                req->se->op.rename(req, nodeid, oldname, arg->newdir, newname,
                                  0);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_rename2(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_rename2_in *arg = (struct fuse_rename2_in *) inarg;
        char *oldname = PARAM(arg);
        char *newname = oldname + strlen(oldname) + 1;
 
        if (req->se->op.rename)
                req->se->op.rename(req, nodeid, oldname, arg->newdir, newname,
                                  arg->flags);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_link(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_link_in *arg = (struct fuse_link_in *) inarg;
 
        if (req->se->op.link)
                req->se->op.link(req, arg->oldnodeid, nodeid, PARAM(arg));
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_create(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_create_in *arg = (struct fuse_create_in *) inarg;
 
        if (req->se->op.create) {
                struct fuse_file_info fi;
                char *name = PARAM(arg);
 
                memset(&fi, 0, sizeof(fi));
                fi.flags = arg->flags;
 
                if (req->se->conn.proto_minor >= 12)
                        req->ctx.umask = arg->umask;
                else
                        name = (char *) inarg + sizeof(struct fuse_open_in);
 
                req->se->op.create(req, nodeid, name, arg->mode, &fi);
        } else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_open(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;
 
        if (req->se->op.open)
                req->se->op.open(req, nodeid, &fi);
        else
                fuse_reply_open(req, &fi);
}
 
static void do_read(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_read_in *arg = (struct fuse_read_in *) inarg;
 
        if (req->se->op.read) {
                struct fuse_file_info fi;
 
                memset(&fi, 0, sizeof(fi));
                fi.fh = arg->fh;
                if (req->se->conn.proto_minor >= 9) {
                        fi.lock_owner = arg->lock_owner;
                        fi.flags = arg->flags;
                }
                req->se->op.read(req, nodeid, arg->size, arg->offset, &fi);
        } else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_write(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
        struct fuse_file_info fi;
        char *param;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.writepage = (arg->write_flags & FUSE_WRITE_CACHE) != 0;
 
        if (req->se->conn.proto_minor < 9) {
                param = ((char *) arg) + FUSE_COMPAT_WRITE_IN_SIZE;
        } else {
                fi.lock_owner = arg->lock_owner;
                fi.flags = arg->flags;
                param = PARAM(arg);
        }
 
        if (req->se->op.write)
                req->se->op.write(req, nodeid, param, arg->size,
                                 arg->offset, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_write_buf(fuse_req_t req, fuse_ino_t nodeid, const void *inarg,
                         const struct fuse_buf *ibuf)
{
        struct fuse_session *se = req->se;
        struct fuse_bufvec bufv = {
                .buf[0] = *ibuf,
                .count = 1,
        };
        struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.writepage = arg->write_flags & FUSE_WRITE_CACHE;
 
        if (se->conn.proto_minor < 9) {
                bufv.buf[0].mem = ((char *) arg) + FUSE_COMPAT_WRITE_IN_SIZE;
                bufv.buf[0].size -= sizeof(struct fuse_in_header) +
                        FUSE_COMPAT_WRITE_IN_SIZE;
                assert(!(bufv.buf[0].flags & FUSE_BUF_IS_FD));
        } else {
                fi.lock_owner = arg->lock_owner;
                fi.flags = arg->flags;
                if (!(bufv.buf[0].flags & FUSE_BUF_IS_FD))
                        bufv.buf[0].mem = PARAM(arg);
 
                bufv.buf[0].size -= sizeof(struct fuse_in_header) +
                        sizeof(struct fuse_write_in);
        }
        if (bufv.buf[0].size < arg->size) {
                fuse_log(FUSE_LOG_ERR, "fuse: do_write_buf: buffer size too small\n");
                fuse_reply_err(req, EIO);
                goto out;
        }
        bufv.buf[0].size = arg->size;
 
        se->op.write_buf(req, nodeid, &bufv, arg->offset, &fi);
 
out:
        /* Need to reset the pipe if ->write_buf() didn't consume all data */
        if ((ibuf->flags & FUSE_BUF_IS_FD) && bufv.idx < bufv.count)
                fuse_ll_clear_pipe(se);
}
 
static void do_flush(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_flush_in *arg = (struct fuse_flush_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.flush = 1;
        if (req->se->conn.proto_minor >= 7)
                fi.lock_owner = arg->lock_owner;
 
        if (req->se->op.flush)
                req->se->op.flush(req, nodeid, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_release(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;
        fi.fh = arg->fh;
        if (req->se->conn.proto_minor >= 8) {
                fi.flush = (arg->release_flags & FUSE_RELEASE_FLUSH) ? 1 : 0;
                fi.lock_owner = arg->lock_owner;
        }
        if (arg->release_flags & FUSE_RELEASE_FLOCK_UNLOCK) {
                fi.flock_release = 1;
                fi.lock_owner = arg->lock_owner;
        }
 
        if (req->se->op.release)
                req->se->op.release(req, nodeid, &fi);
        else
                fuse_reply_err(req, 0);
}
 
static void do_fsync(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
        struct fuse_file_info fi;
        int datasync = arg->fsync_flags & 1;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.fsync)
                req->se->op.fsync(req, nodeid, datasync, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_opendir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;
 
        if (req->se->op.opendir)
                req->se->op.opendir(req, nodeid, &fi);
        else
                fuse_reply_open(req, &fi);
}
 
static void do_readdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_read_in *arg = (struct fuse_read_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.readdir)
                req->se->op.readdir(req, nodeid, arg->size, arg->offset, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_readdirplus(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_read_in *arg = (struct fuse_read_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.readdirplus)
                req->se->op.readdirplus(req, nodeid, arg->size, arg->offset, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_releasedir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;
        fi.fh = arg->fh;
 
        if (req->se->op.releasedir)
                req->se->op.releasedir(req, nodeid, &fi);
        else
                fuse_reply_err(req, 0);
}
 
static void do_fsyncdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
        struct fuse_file_info fi;
        int datasync = arg->fsync_flags & 1;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.fsyncdir)
                req->se->op.fsyncdir(req, nodeid, datasync, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_statfs(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        (void) nodeid;
        (void) inarg;
 
        if (req->se->op.statfs)
                req->se->op.statfs(req, nodeid);
        else {
                struct statvfs buf = {
                        .f_namemax = 255,
                        .f_bsize = 512,
                };
                fuse_reply_statfs(req, &buf);
        }
}
 
static void do_setxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_setxattr_in *arg = (struct fuse_setxattr_in *) inarg;
        char *name = PARAM(arg);
        char *value = name + strlen(name) + 1;
 
        if (req->se->op.setxattr)
                req->se->op.setxattr(req, nodeid, name, value, arg->size,
                                    arg->flags);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_getxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;
 
        if (req->se->op.getxattr)
                req->se->op.getxattr(req, nodeid, PARAM(arg), arg->size);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_listxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;
 
        if (req->se->op.listxattr)
                req->se->op.listxattr(req, nodeid, arg->size);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_removexattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        char *name = (char *) inarg;
 
        if (req->se->op.removexattr)
                req->se->op.removexattr(req, nodeid, name);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void convert_fuse_file_lock(struct fuse_file_lock *fl,
                                   struct flock *flock)
{
        memset(flock, 0, sizeof(struct flock));
        flock->l_type = fl->type;
        flock->l_whence = SEEK_SET;
        flock->l_start = fl->start;
        if (fl->end == OFFSET_MAX)
                flock->l_len = 0;
        else
                flock->l_len = fl->end - fl->start + 1;
        flock->l_pid = fl->pid;
}
 
static void do_getlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
        struct fuse_file_info fi;
        struct flock flock;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.lock_owner = arg->owner;
 
        convert_fuse_file_lock(&arg->lk, &flock);
        if (req->se->op.getlk)
                req->se->op.getlk(req, nodeid, &fi, &flock);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_setlk_common(fuse_req_t req, fuse_ino_t nodeid,
                            const void *inarg, int sleep)
{
        struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
        struct fuse_file_info fi;
        struct flock flock;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.lock_owner = arg->owner;
 
        if (arg->lk_flags & FUSE_LK_FLOCK) {
                int op = 0;
 
                switch (arg->lk.type) {
                case F_RDLCK:
                        op = LOCK_SH;
                        break;
                case F_WRLCK:
                        op = LOCK_EX;
                        break;
                case F_UNLCK:
                        op = LOCK_UN;
                        break;
                }
                if (!sleep)
                        op |= LOCK_NB;
 
                if (req->se->op.flock)
                        req->se->op.flock(req, nodeid, &fi, op);
                else
                        fuse_reply_err(req, ENOSYS);
        } else {
                convert_fuse_file_lock(&arg->lk, &flock);
                if (req->se->op.setlk)
                        req->se->op.setlk(req, nodeid, &fi, &flock, sleep);
                else
                        fuse_reply_err(req, ENOSYS);
        }
}
 
static void do_setlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        do_setlk_common(req, nodeid, inarg, 0);
}
 
static void do_setlkw(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        do_setlk_common(req, nodeid, inarg, 1);
}
 
static int find_interrupted(struct fuse_session *se, struct fuse_req *req)
{
        struct fuse_req *curr;
 
        for (curr = se->list.next; curr != &se->list; curr = curr->next) {
                if (curr->unique == req->u.i.unique) {
                        fuse_interrupt_func_t func;
                        void *data;
 
                        curr->ctr++;
                        pthread_mutex_unlock(&se->lock);
 
                        /* Ugh, ugly locking */
                        pthread_mutex_lock(&curr->lock);
                        pthread_mutex_lock(&se->lock);
                        curr->interrupted = 1;
                        func = curr->u.ni.func;
                        data = curr->u.ni.data;
                        pthread_mutex_unlock(&se->lock);
                        if (func)
                                func(curr, data);
                        pthread_mutex_unlock(&curr->lock);
 
                        pthread_mutex_lock(&se->lock);
                        curr->ctr--;
                        if (!curr->ctr)
                                destroy_req(curr);
 
                        return 1;
                }
        }
        for (curr = se->interrupts.next; curr != &se->interrupts;
             curr = curr->next) {
                if (curr->u.i.unique == req->u.i.unique)
                        return 1;
        }
        return 0;
}
 
static void do_interrupt(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_interrupt_in *arg = (struct fuse_interrupt_in *) inarg;
        struct fuse_session *se = req->se;
 
        (void) nodeid;
        if (se->debug)
                fuse_log(FUSE_LOG_DEBUG, "INTERRUPT: %llu\n",
                        (unsigned long long) arg->unique);
 
        req->u.i.unique = arg->unique;
 
        pthread_mutex_lock(&se->lock);
        if (find_interrupted(se, req))
                destroy_req(req);
        else
                list_add_req(req, &se->interrupts);
        pthread_mutex_unlock(&se->lock);
}
 
static struct fuse_req *check_interrupt(struct fuse_session *se,
                                        struct fuse_req *req)
{
        struct fuse_req *curr;
 
        for (curr = se->interrupts.next; curr != &se->interrupts;
             curr = curr->next) {
                if (curr->u.i.unique == req->unique) {
                        req->interrupted = 1;
                        list_del_req(curr);
                        free(curr);
                        return NULL;
                }
        }
        curr = se->interrupts.next;
        if (curr != &se->interrupts) {
                list_del_req(curr);
                list_init_req(curr);
                return curr;
        } else
                return NULL;
}
 
static void do_bmap(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_bmap_in *arg = (struct fuse_bmap_in *) inarg;
 
        if (req->se->op.bmap)
                req->se->op.bmap(req, nodeid, arg->blocksize, arg->block);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_ioctl(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_ioctl_in *arg = (struct fuse_ioctl_in *) inarg;
        unsigned int flags = arg->flags;
        void *in_buf = arg->in_size ? PARAM(arg) : NULL;
        struct fuse_file_info fi;
 
        if (flags & FUSE_IOCTL_DIR &&
            !(req->se->conn.want & FUSE_CAP_IOCTL_DIR)) {
                fuse_reply_err(req, ENOTTY);
                return;
        }
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (sizeof(void *) == 4 && req->se->conn.proto_minor >= 16 &&
            !(flags & FUSE_IOCTL_32BIT)) {
                req->ioctl_64bit = 1;
        }
 
        if (req->se->op.ioctl)
                req->se->op.ioctl(req, nodeid, arg->cmd,
                                 (void *)(uintptr_t)arg->arg, &fi, flags,
                                 in_buf, arg->in_size, arg->out_size);
        else
                fuse_reply_err(req, ENOSYS);
}
 
void fuse_pollhandle_destroy(struct fuse_pollhandle *ph)
{
        free(ph);
}
 
static void do_poll(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_poll_in *arg = (struct fuse_poll_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.poll_events = arg->events;
 
        if (req->se->op.poll) {
                struct fuse_pollhandle *ph = NULL;
 
                if (arg->flags & FUSE_POLL_SCHEDULE_NOTIFY) {
                        ph = malloc(sizeof(struct fuse_pollhandle));
                        if (ph == NULL) {
                                fuse_reply_err(req, ENOMEM);
                                return;
                        }
                        ph->kh = arg->kh;
                        ph->se = req->se;
                }
 
                req->se->op.poll(req, nodeid, &fi, ph);
        } else {
                fuse_reply_err(req, ENOSYS);
        }
}
 
static void do_fallocate(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_fallocate_in *arg = (struct fuse_fallocate_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.fallocate)
                req->se->op.fallocate(req, nodeid, arg->mode, arg->offset, arg->length, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_copy_file_range(fuse_req_t req, fuse_ino_t nodeid_in, const void *inarg)
{
        struct fuse_copy_file_range_in *arg = (struct fuse_copy_file_range_in *) inarg;
        struct fuse_file_info fi_in, fi_out;
 
        memset(&fi_in, 0, sizeof(fi_in));
        fi_in.fh = arg->fh_in;
 
        memset(&fi_out, 0, sizeof(fi_out));
        fi_out.fh = arg->fh_out;
 
 
        if (req->se->op.copy_file_range)
                req->se->op.copy_file_range(req, nodeid_in, arg->off_in,
                                            &fi_in, arg->nodeid_out,
                                            arg->off_out, &fi_out, arg->len,
                                            arg->flags);
        else
                fuse_reply_err(req, ENOSYS);
}
 
static void do_lseek(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_lseek_in *arg = (struct fuse_lseek_in *) inarg;
        struct fuse_file_info fi;
 
        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
 
        if (req->se->op.lseek)
                req->se->op.lseek(req, nodeid, arg->offset, arg->whence, &fi);
        else
                fuse_reply_err(req, ENOSYS);
}
 
/* Prevent bogus data races (bogus since "init" is called before
 * multi-threading becomes relevant */
static __attribute__((no_sanitize("thread")))
void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_init_in *arg = (struct fuse_init_in *) inarg;
        struct fuse_init_out outarg;
        struct fuse_session *se = req->se;
        size_t bufsize = se->bufsize;
        size_t outargsize = sizeof(outarg);
 
        (void) nodeid;
        if (se->debug) {
                fuse_log(FUSE_LOG_DEBUG, "INIT: %u.%u\n", arg->major, arg->minor);
                if (arg->major == 7 && arg->minor >= 6) {
                        fuse_log(FUSE_LOG_DEBUG, "flags=0x%08x\n", arg->flags);
                        fuse_log(FUSE_LOG_DEBUG, "max_readahead=0x%08x\n",
                                arg->max_readahead);
                }
        }
        se->conn.proto_major = arg->major;
        se->conn.proto_minor = arg->minor;
        se->conn.capable = 0;
        se->conn.want = 0;
 
        memset(&outarg, 0, sizeof(outarg));
        outarg.major = FUSE_KERNEL_VERSION;
        outarg.minor = FUSE_KERNEL_MINOR_VERSION;
 
        if (arg->major < 7) {
                fuse_log(FUSE_LOG_ERR, "fuse: unsupported protocol version: %u.%u\n",
                        arg->major, arg->minor);
                fuse_reply_err(req, EPROTO);
                return;
        }
 
        if (arg->major > 7) {
                /* Wait for a second INIT request with a 7.X version */
                send_reply_ok(req, &outarg, sizeof(outarg));
                return;
        }
 
        if (arg->minor >= 6) {
                if (arg->max_readahead < se->conn.max_readahead)
                        se->conn.max_readahead = arg->max_readahead;
                if (arg->flags & FUSE_ASYNC_READ)
                        se->conn.capable |= FUSE_CAP_ASYNC_READ;
                if (arg->flags & FUSE_POSIX_LOCKS)
                        se->conn.capable |= FUSE_CAP_POSIX_LOCKS;
                if (arg->flags & FUSE_ATOMIC_O_TRUNC)
                        se->conn.capable |= FUSE_CAP_ATOMIC_O_TRUNC;
                if (arg->flags & FUSE_EXPORT_SUPPORT)
                        se->conn.capable |= FUSE_CAP_EXPORT_SUPPORT;
                if (arg->flags & FUSE_DONT_MASK)
                        se->conn.capable |= FUSE_CAP_DONT_MASK;
                if (arg->flags & FUSE_FLOCK_LOCKS)
                        se->conn.capable |= FUSE_CAP_FLOCK_LOCKS;
                if (arg->flags & FUSE_AUTO_INVAL_DATA)
                        se->conn.capable |= FUSE_CAP_AUTO_INVAL_DATA;
                if (arg->flags & FUSE_DO_READDIRPLUS)
                        se->conn.capable |= FUSE_CAP_READDIRPLUS;
                if (arg->flags & FUSE_READDIRPLUS_AUTO)
                        se->conn.capable |= FUSE_CAP_READDIRPLUS_AUTO;
                if (arg->flags & FUSE_ASYNC_DIO)
                        se->conn.capable |= FUSE_CAP_ASYNC_DIO;
                if (arg->flags & FUSE_WRITEBACK_CACHE)
                        se->conn.capable |= FUSE_CAP_WRITEBACK_CACHE;
                if (arg->flags & FUSE_NO_OPEN_SUPPORT)
                        se->conn.capable |= FUSE_CAP_NO_OPEN_SUPPORT;
                if (arg->flags & FUSE_PARALLEL_DIROPS)
                        se->conn.capable |= FUSE_CAP_PARALLEL_DIROPS;
                if (arg->flags & FUSE_POSIX_ACL)
                        se->conn.capable |= FUSE_CAP_POSIX_ACL;
                if (arg->flags & FUSE_HANDLE_KILLPRIV)
                        se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV;
                if (arg->flags & FUSE_CACHE_SYMLINKS)
                        se->conn.capable |= FUSE_CAP_CACHE_SYMLINKS;
                if (arg->flags & FUSE_NO_OPENDIR_SUPPORT)
                        se->conn.capable |= FUSE_CAP_NO_OPENDIR_SUPPORT;
                if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
                        se->conn.capable |= FUSE_CAP_EXPLICIT_INVAL_DATA;
                if (!(arg->flags & FUSE_MAX_PAGES)) {
                        size_t max_bufsize =
                                FUSE_DEFAULT_MAX_PAGES_PER_REQ * getpagesize()
                                + FUSE_BUFFER_HEADER_SIZE;
                        if (bufsize > max_bufsize) {
                                bufsize = max_bufsize;
                        }
                }
        } else {
                se->conn.max_readahead = 0;
        }
 
        if (se->conn.proto_minor >= 14) {
#ifdef HAVE_SPLICE
#ifdef HAVE_VMSPLICE
                se->conn.capable |= FUSE_CAP_SPLICE_WRITE | FUSE_CAP_SPLICE_MOVE;
#endif
                se->conn.capable |= FUSE_CAP_SPLICE_READ;
#endif
        }
        if (se->conn.proto_minor >= 18)
                se->conn.capable |= FUSE_CAP_IOCTL_DIR;
 
        /* Default settings for modern filesystems.
         *
         * Most of these capabilities were disabled by default in
         * libfuse2 for backwards compatibility reasons. In libfuse3,
         * we can finally enable them by default (as long as they're
         * supported by the kernel).
         */
#define LL_SET_DEFAULT(cond, cap) \
        if ((cond) && (se->conn.capable & (cap))) \
                se->conn.want |= (cap)
        LL_SET_DEFAULT(1, FUSE_CAP_ASYNC_READ);
        LL_SET_DEFAULT(1, FUSE_CAP_PARALLEL_DIROPS);
        LL_SET_DEFAULT(1, FUSE_CAP_AUTO_INVAL_DATA);
        LL_SET_DEFAULT(1, FUSE_CAP_HANDLE_KILLPRIV);
        LL_SET_DEFAULT(1, FUSE_CAP_ASYNC_DIO);
        LL_SET_DEFAULT(1, FUSE_CAP_IOCTL_DIR);
        LL_SET_DEFAULT(1, FUSE_CAP_ATOMIC_O_TRUNC);
        LL_SET_DEFAULT(se->op.write_buf, FUSE_CAP_SPLICE_READ);
        LL_SET_DEFAULT(se->op.getlk && se->op.setlk,
                       FUSE_CAP_POSIX_LOCKS);
        LL_SET_DEFAULT(se->op.flock, FUSE_CAP_FLOCK_LOCKS);
        LL_SET_DEFAULT(se->op.readdirplus, FUSE_CAP_READDIRPLUS);
        LL_SET_DEFAULT(se->op.readdirplus && se->op.readdir,
                       FUSE_CAP_READDIRPLUS_AUTO);
        se->conn.time_gran = 1;
        
        if (bufsize < FUSE_MIN_READ_BUFFER) {
                fuse_log(FUSE_LOG_ERR, "fuse: warning: buffer size too small: %zu\n",
                        bufsize);
                bufsize = FUSE_MIN_READ_BUFFER;
        }
        se->bufsize = bufsize;
 
        if (se->conn.max_write > bufsize - FUSE_BUFFER_HEADER_SIZE)
                se->conn.max_write = bufsize - FUSE_BUFFER_HEADER_SIZE;
 
        se->got_init = 1;
        if (se->op.init)
                se->op.init(se->userdata, &se->conn);
 
        if (se->conn.want & (~se->conn.capable)) {
                fuse_log(FUSE_LOG_ERR, "fuse: error: filesystem requested capabilities "
                        "0x%x that are not supported by kernel, aborting.\n",
                        se->conn.want & (~se->conn.capable));
                fuse_reply_err(req, EPROTO);
                se->error = -EPROTO;
                fuse_session_exit(se);
                return;
        }
 
        unsigned max_read_mo = get_max_read(se->mo);
        if (se->conn.max_read != max_read_mo) {
                fuse_log(FUSE_LOG_ERR, "fuse: error: init() and fuse_session_new() "
                        "requested different maximum read size (%u vs %u)\n",
                        se->conn.max_read, max_read_mo);
                fuse_reply_err(req, EPROTO);
                se->error = -EPROTO;
                fuse_session_exit(se);
                return;
        }
 
        if (se->conn.max_write < bufsize - FUSE_BUFFER_HEADER_SIZE) {
                se->bufsize = se->conn.max_write + FUSE_BUFFER_HEADER_SIZE;
        }
        if (arg->flags & FUSE_MAX_PAGES) {
                outarg.flags |= FUSE_MAX_PAGES;
                outarg.max_pages = (se->conn.max_write - 1) / getpagesize() + 1;
        }
 
        /* Always enable big writes, this is superseded
           by the max_write option */
        outarg.flags |= FUSE_BIG_WRITES;
 
        if (se->conn.want & FUSE_CAP_ASYNC_READ)
                outarg.flags |= FUSE_ASYNC_READ;
        if (se->conn.want & FUSE_CAP_POSIX_LOCKS)
                outarg.flags |= FUSE_POSIX_LOCKS;
        if (se->conn.want & FUSE_CAP_ATOMIC_O_TRUNC)
                outarg.flags |= FUSE_ATOMIC_O_TRUNC;
        if (se->conn.want & FUSE_CAP_EXPORT_SUPPORT)
                outarg.flags |= FUSE_EXPORT_SUPPORT;
        if (se->conn.want & FUSE_CAP_DONT_MASK)
                outarg.flags |= FUSE_DONT_MASK;
        if (se->conn.want & FUSE_CAP_FLOCK_LOCKS)
                outarg.flags |= FUSE_FLOCK_LOCKS;
        if (se->conn.want & FUSE_CAP_AUTO_INVAL_DATA)
                outarg.flags |= FUSE_AUTO_INVAL_DATA;
        if (se->conn.want & FUSE_CAP_READDIRPLUS)
                outarg.flags |= FUSE_DO_READDIRPLUS;
        if (se->conn.want & FUSE_CAP_READDIRPLUS_AUTO)
                outarg.flags |= FUSE_READDIRPLUS_AUTO;
        if (se->conn.want & FUSE_CAP_ASYNC_DIO)
                outarg.flags |= FUSE_ASYNC_DIO;
        if (se->conn.want & FUSE_CAP_WRITEBACK_CACHE)
                outarg.flags |= FUSE_WRITEBACK_CACHE;
        if (se->conn.want & FUSE_CAP_POSIX_ACL)
                outarg.flags |= FUSE_POSIX_ACL;
        if (se->conn.want & FUSE_CAP_CACHE_SYMLINKS)
                outarg.flags |= FUSE_CACHE_SYMLINKS;
        if (se->conn.want & FUSE_CAP_EXPLICIT_INVAL_DATA)
                outarg.flags |= FUSE_EXPLICIT_INVAL_DATA;
        outarg.max_readahead = se->conn.max_readahead;
        outarg.max_write = se->conn.max_write;
        if (se->conn.proto_minor >= 13) {
                if (se->conn.max_background >= (1 << 16))
                        se->conn.max_background = (1 << 16) - 1;
                if (se->conn.congestion_threshold > se->conn.max_background)
                        se->conn.congestion_threshold = se->conn.max_background;
                if (!se->conn.congestion_threshold) {
                        se->conn.congestion_threshold =
                                se->conn.max_background * 3 / 4;
                }
 
                outarg.max_background = se->conn.max_background;
                outarg.congestion_threshold = se->conn.congestion_threshold;
        }
        if (se->conn.proto_minor >= 23)
                outarg.time_gran = se->conn.time_gran;
 
        if (se->debug) {
                fuse_log(FUSE_LOG_DEBUG, "   INIT: %u.%u\n", outarg.major, outarg.minor);
                fuse_log(FUSE_LOG_DEBUG, "   flags=0x%08x\n", outarg.flags);
                fuse_log(FUSE_LOG_DEBUG, "   max_readahead=0x%08x\n",
                        outarg.max_readahead);
                fuse_log(FUSE_LOG_DEBUG, "   max_write=0x%08x\n", outarg.max_write);
                fuse_log(FUSE_LOG_DEBUG, "   max_background=%i\n",
                        outarg.max_background);
                fuse_log(FUSE_LOG_DEBUG, "   congestion_threshold=%i\n",
                        outarg.congestion_threshold);
                fuse_log(FUSE_LOG_DEBUG, "   time_gran=%u\n",
                        outarg.time_gran);
        }
        if (arg->minor < 5)
                outargsize = FUSE_COMPAT_INIT_OUT_SIZE;
        else if (arg->minor < 23)
                outargsize = FUSE_COMPAT_22_INIT_OUT_SIZE;
 
        send_reply_ok(req, &outarg, outargsize);
}
 
static void do_destroy(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
        struct fuse_session *se = req->se;
 
        (void) nodeid;
        (void) inarg;
 
        se->got_destroy = 1;
        if (se->op.destroy)
                se->op.destroy(se->userdata);
 
        send_reply_ok(req, NULL, 0);
}
 
static void list_del_nreq(struct fuse_notify_req *nreq)
{
        struct fuse_notify_req *prev = nreq->prev;
        struct fuse_notify_req *next = nreq->next;
        prev->next = next;
        next->prev = prev;
}
 
static void list_add_nreq(struct fuse_notify_req *nreq,
                          struct fuse_notify_req *next)
{
        struct fuse_notify_req *prev = next->prev;
        nreq->next = next;
        nreq->prev = prev;
        prev->next = nreq;
        next->prev = nreq;
}
 
static void list_init_nreq(struct fuse_notify_req *nreq)
{
        nreq->next = nreq;
        nreq->prev = nreq;
}
 
static void do_notify_reply(fuse_req_t req, fuse_ino_t nodeid,
                            const void *inarg, const struct fuse_buf *buf)
{
        struct fuse_session *se = req->se;
        struct fuse_notify_req *nreq;
        struct fuse_notify_req *head;
 
        pthread_mutex_lock(&se->lock);
        head = &se->notify_list;
        for (nreq = head->next; nreq != head; nreq = nreq->next) {
                if (nreq->unique == req->unique) {
                        list_del_nreq(nreq);
                        break;
                }
        }
        pthread_mutex_unlock(&se->lock);
 
        if (nreq != head)
                nreq->reply(nreq, req, nodeid, inarg, buf);
}
 
static int send_notify_iov(struct fuse_session *se, int notify_code,
                           struct iovec *iov, int count)
{
        struct fuse_out_header out;
 
        if (!se->got_init)
                return -ENOTCONN;
 
        out.unique = 0;
        out.error = notify_code;
        iov[0].iov_base = &out;
        iov[0].iov_len = sizeof(struct fuse_out_header);
 
        return fuse_send_msg(se, NULL, iov, count);
}
 
int fuse_lowlevel_notify_poll(struct fuse_pollhandle *ph)
{
        if (ph != NULL) {
                struct fuse_notify_poll_wakeup_out outarg;
                struct iovec iov[2];
 
                outarg.kh = ph->kh;
 
                iov[1].iov_base = &outarg;
                iov[1].iov_len = sizeof(outarg);
 
                return send_notify_iov(ph->se, FUSE_NOTIFY_POLL, iov, 2);
        } else {
                return 0;
        }
}
 
int fuse_lowlevel_notify_inval_inode(struct fuse_session *se, fuse_ino_t ino,
                                     off_t off, off_t len)
{
        struct fuse_notify_inval_inode_out outarg;
        struct iovec iov[2];
 
        if (!se)
                return -EINVAL;
 
        if (se->conn.proto_minor < 12)
                return -ENOSYS;
        
        outarg.ino = ino;
        outarg.off = off;
        outarg.len = len;
 
        iov[1].iov_base = &outarg;
        iov[1].iov_len = sizeof(outarg);
 
        return send_notify_iov(se, FUSE_NOTIFY_INVAL_INODE, iov, 2);
}
 
int fuse_lowlevel_notify_inval_entry(struct fuse_session *se, fuse_ino_t parent,
                                     const char *name, size_t namelen)
{
        struct fuse_notify_inval_entry_out outarg;
        struct iovec iov[3];
 
        if (!se)
                return -EINVAL;
        
        if (se->conn.proto_minor < 12)
                return -ENOSYS;
 
        outarg.parent = parent;
        outarg.namelen = namelen;
        outarg.padding = 0;
 
        iov[1].iov_base = &outarg;
        iov[1].iov_len = sizeof(outarg);
        iov[2].iov_base = (void *)name;
        iov[2].iov_len = namelen + 1;
 
        return send_notify_iov(se, FUSE_NOTIFY_INVAL_ENTRY, iov, 3);
}
 
int fuse_lowlevel_notify_delete(struct fuse_session *se,
                                fuse_ino_t parent, fuse_ino_t child,
                                const char *name, size_t namelen)
{
        struct fuse_notify_delete_out outarg;
        struct iovec iov[3];
 
        if (!se)
                return -EINVAL;
 
        if (se->conn.proto_minor < 18)
                return -ENOSYS;
 
        outarg.parent = parent;
        outarg.child = child;
        outarg.namelen = namelen;
        outarg.padding = 0;
 
        iov[1].iov_base = &outarg;
        iov[1].iov_len = sizeof(outarg);
        iov[2].iov_base = (void *)name;
        iov[2].iov_len = namelen + 1;
 
        return send_notify_iov(se, FUSE_NOTIFY_DELETE, iov, 3);
}
 
int fuse_lowlevel_notify_store(struct fuse_session *se, fuse_ino_t ino,
                               off_t offset, struct fuse_bufvec *bufv,
                               enum fuse_buf_copy_flags flags)
{
        struct fuse_out_header out;
        struct fuse_notify_store_out outarg;
        struct iovec iov[3];
        size_t size = fuse_buf_size(bufv);
        int res;
 
        if (!se)
                return -EINVAL;
 
        if (se->conn.proto_minor < 15)
                return -ENOSYS;
 
        out.unique = 0;
        out.error = FUSE_NOTIFY_STORE;
 
        outarg.nodeid = ino;
        outarg.offset = offset;
        outarg.size = size;
        outarg.padding = 0;
 
        iov[0].iov_base = &out;
        iov[0].iov_len = sizeof(out);
        iov[1].iov_base = &outarg;
        iov[1].iov_len = sizeof(outarg);
 
        res = fuse_send_data_iov(se, NULL, iov, 2, bufv, flags);
        if (res > 0)
                res = -res;
 
        return res;
}
 
struct fuse_retrieve_req {
        struct fuse_notify_req nreq;
        void *cookie;
};
 
static void fuse_ll_retrieve_reply(struct fuse_notify_req *nreq,
                                   fuse_req_t req, fuse_ino_t ino,
                                   const void *inarg,
                                   const struct fuse_buf *ibuf)
{
        struct fuse_session *se = req->se;
        struct fuse_retrieve_req *rreq =
                container_of(nreq, struct fuse_retrieve_req, nreq);
        const struct fuse_notify_retrieve_in *arg = inarg;
        struct fuse_bufvec bufv = {
                .buf[0] = *ibuf,
                .count = 1,
        };
 
        if (!(bufv.buf[0].flags & FUSE_BUF_IS_FD))
                bufv.buf[0].mem = PARAM(arg);
 
        bufv.buf[0].size -= sizeof(struct fuse_in_header) +
                sizeof(struct fuse_notify_retrieve_in);
 
        if (bufv.buf[0].size < arg->size) {
                fuse_log(FUSE_LOG_ERR, "fuse: retrieve reply: buffer size too small\n");
                fuse_reply_none(req);
                goto out;
        }
        bufv.buf[0].size = arg->size;
 
        if (se->op.retrieve_reply) {
                se->op.retrieve_reply(req, rreq->cookie, ino,
                                          arg->offset, &bufv);
        } else {
                fuse_reply_none(req);
        }
out:
        free(rreq);
        if ((ibuf->flags & FUSE_BUF_IS_FD) && bufv.idx < bufv.count)
                fuse_ll_clear_pipe(se);
}
 
int fuse_lowlevel_notify_retrieve(struct fuse_session *se, fuse_ino_t ino,
                                  size_t size, off_t offset, void *cookie)
{
        struct fuse_notify_retrieve_out outarg;
        struct iovec iov[2];
        struct fuse_retrieve_req *rreq;
        int err;
 
        if (!se)
                return -EINVAL;
 
        if (se->conn.proto_minor < 15)
                return -ENOSYS;
 
        rreq = malloc(sizeof(*rreq));
        if (rreq == NULL)
                return -ENOMEM;
 
        pthread_mutex_lock(&se->lock);
        rreq->cookie = cookie;
        rreq->nreq.unique = se->notify_ctr++;
        rreq->nreq.reply = fuse_ll_retrieve_reply;
        list_add_nreq(&rreq->nreq, &se->notify_list);
        pthread_mutex_unlock(&se->lock);
 
        outarg.notify_unique = rreq->nreq.unique;
        outarg.nodeid = ino;
        outarg.offset = offset;
        outarg.size = size;
        outarg.padding = 0;
 
        iov[1].iov_base = &outarg;
        iov[1].iov_len = sizeof(outarg);
 
        err = send_notify_iov(se, FUSE_NOTIFY_RETRIEVE, iov, 2);
        if (err) {
                pthread_mutex_lock(&se->lock);
                list_del_nreq(&rreq->nreq);
                pthread_mutex_unlock(&se->lock);
                free(rreq);
        }
 
        return err;
}
 
void *fuse_req_userdata(fuse_req_t req)
{
        return req->se->userdata;
}
 
const struct fuse_ctx *fuse_req_ctx(fuse_req_t req)
{
        return &req->ctx;
}
 
void fuse_req_interrupt_func(fuse_req_t req, fuse_interrupt_func_t func,
                             void *data)
{
        pthread_mutex_lock(&req->lock);
        pthread_mutex_lock(&req->se->lock);
        req->u.ni.func = func;
        req->u.ni.data = data;
        pthread_mutex_unlock(&req->se->lock);
        if (req->interrupted && func)
                func(req, data);
        pthread_mutex_unlock(&req->lock);
}
 
int fuse_req_interrupted(fuse_req_t req)
{
        int interrupted;
 
        pthread_mutex_lock(&req->se->lock);
        interrupted = req->interrupted;
        pthread_mutex_unlock(&req->se->lock);
 
        return interrupted;
}
 
static struct {
        void (*func)(fuse_req_t, fuse_ino_t, const void *);
        const char *name;
} fuse_ll_ops[] = {
        [FUSE_LOOKUP]      = { do_lookup,      "LOOKUP"      },
        [FUSE_FORGET]      = { do_forget,      "FORGET"      },
        [FUSE_GETATTR]     = { do_getattr,     "GETATTR"     },
        [FUSE_SETATTR]     = { do_setattr,     "SETATTR"     },
        [FUSE_READLINK]    = { do_readlink,    "READLINK"    },
        [FUSE_SYMLINK]     = { do_symlink,     "SYMLINK"     },
        [FUSE_MKNOD]       = { do_mknod,       "MKNOD"       },
        [FUSE_MKDIR]       = { do_mkdir,       "MKDIR"       },
        [FUSE_UNLINK]      = { do_unlink,      "UNLINK"      },
        [FUSE_RMDIR]       = { do_rmdir,       "RMDIR"       },
        [FUSE_RENAME]      = { do_rename,      "RENAME"      },
        [FUSE_LINK]        = { do_link,        "LINK"        },
        [FUSE_OPEN]        = { do_open,        "OPEN"        },
        [FUSE_READ]        = { do_read,        "READ"        },
        [FUSE_WRITE]       = { do_write,       "WRITE"       },
        [FUSE_STATFS]      = { do_statfs,      "STATFS"      },
        [FUSE_RELEASE]     = { do_release,     "RELEASE"     },
        [FUSE_FSYNC]       = { do_fsync,       "FSYNC"       },
        [FUSE_SETXATTR]    = { do_setxattr,    "SETXATTR"    },
        [FUSE_GETXATTR]    = { do_getxattr,    "GETXATTR"    },
        [FUSE_LISTXATTR]   = { do_listxattr,   "LISTXATTR"   },
        [FUSE_REMOVEXATTR] = { do_removexattr, "REMOVEXATTR" },
        [FUSE_FLUSH]       = { do_flush,       "FLUSH"       },
        [FUSE_INIT]        = { do_init,        "INIT"        },
        [FUSE_OPENDIR]     = { do_opendir,     "OPENDIR"     },
        [FUSE_READDIR]     = { do_readdir,     "READDIR"     },
        [FUSE_RELEASEDIR]  = { do_releasedir,  "RELEASEDIR"  },
        [FUSE_FSYNCDIR]    = { do_fsyncdir,    "FSYNCDIR"    },
        [FUSE_GETLK]       = { do_getlk,       "GETLK"       },
        [FUSE_SETLK]       = { do_setlk,       "SETLK"       },
        [FUSE_SETLKW]      = { do_setlkw,      "SETLKW"      },
        [FUSE_ACCESS]      = { do_access,      "ACCESS"      },
        [FUSE_CREATE]      = { do_create,      "CREATE"      },
        [FUSE_INTERRUPT]   = { do_interrupt,   "INTERRUPT"   },
        [FUSE_BMAP]        = { do_bmap,        "BMAP"        },
        [FUSE_IOCTL]       = { do_ioctl,       "IOCTL"       },
        [FUSE_POLL]        = { do_poll,        "POLL"        },
        [FUSE_FALLOCATE]   = { do_fallocate,   "FALLOCATE"   },
        [FUSE_DESTROY]     = { do_destroy,     "DESTROY"     },
        [FUSE_NOTIFY_REPLY] = { (void *) 1,    "NOTIFY_REPLY" },
        [FUSE_BATCH_FORGET] = { do_batch_forget, "BATCH_FORGET" },
        [FUSE_READDIRPLUS] = { do_readdirplus,  "READDIRPLUS"},
        [FUSE_RENAME2]     = { do_rename2,      "RENAME2"    },
        [FUSE_COPY_FILE_RANGE] = { do_copy_file_range, "COPY_FILE_RANGE" },
        [FUSE_LSEEK]       = { do_lseek,       "LSEEK"       },
        [CUSE_INIT]        = { cuse_lowlevel_init, "CUSE_INIT"   },
};
 
#define FUSE_MAXOP (sizeof(fuse_ll_ops) / sizeof(fuse_ll_ops[0]))
 
static const char *opname(enum fuse_opcode opcode)
{
        if (opcode >= FUSE_MAXOP || !fuse_ll_ops[opcode].name)
                return "???";
        else
                return fuse_ll_ops[opcode].name;
}
 
static int fuse_ll_copy_from_pipe(struct fuse_bufvec *dst,
                                  struct fuse_bufvec *src)
{
        ssize_t res = fuse_buf_copy(dst, src, 0);
        if (res < 0) {
                fuse_log(FUSE_LOG_ERR, "fuse: copy from pipe: %s\n", strerror(-res));
                return res;
        }
        if ((size_t)res < fuse_buf_size(dst)) {
                fuse_log(FUSE_LOG_ERR, "fuse: copy from pipe: short read\n");
                return -1;
        }
        return 0;
}
 
void fuse_session_process_buf(struct fuse_session *se,
                              const struct fuse_buf *buf)
{
        fuse_session_process_buf_int(se, buf, NULL);
}
 
void fuse_session_process_buf_int(struct fuse_session *se,
                                  const struct fuse_buf *buf, struct fuse_chan *ch)
{
        const size_t write_header_size = sizeof(struct fuse_in_header) +
                sizeof(struct fuse_write_in);
        struct fuse_bufvec bufv = { .buf[0] = *buf, .count = 1 };
        struct fuse_bufvec tmpbuf = FUSE_BUFVEC_INIT(write_header_size);
        struct fuse_in_header *in;
        const void *inarg;
        struct fuse_req *req;
        void *mbuf = NULL;
        int err;
        int res;
 
        if (buf->flags & FUSE_BUF_IS_FD) {
                if (buf->size < tmpbuf.buf[0].size)
                        tmpbuf.buf[0].size = buf->size;
 
                mbuf = malloc(tmpbuf.buf[0].size);
                if (mbuf == NULL) {
                        fuse_log(FUSE_LOG_ERR, "fuse: failed to allocate header\n");
                        goto clear_pipe;
                }
                tmpbuf.buf[0].mem = mbuf;
 
                res = fuse_ll_copy_from_pipe(&tmpbuf, &bufv);
                if (res < 0)
                        goto clear_pipe;
 
                in = mbuf;
        } else {
                in = buf->mem;
        }
 
        if (se->debug) {
                fuse_log(FUSE_LOG_DEBUG,
                        "unique: %llu, opcode: %s (%i), nodeid: %llu, insize: %zu, pid: %u\n",
                        (unsigned long long) in->unique,
                        opname((enum fuse_opcode) in->opcode), in->opcode,
                        (unsigned long long) in->nodeid, buf->size, in->pid);
        }
 
        req = fuse_ll_alloc_req(se);
        if (req == NULL) {
                struct fuse_out_header out = {
                        .unique = in->unique,
                        .error = -ENOMEM,
                };
                struct iovec iov = {
                        .iov_base = &out,
                        .iov_len = sizeof(struct fuse_out_header),
                };
 
                fuse_send_msg(se, ch, &iov, 1);
                goto clear_pipe;
        }
 
        req->unique = in->unique;
        req->ctx.uid = in->uid;
        req->ctx.gid = in->gid;
        req->ctx.pid = in->pid;
        req->ch = ch ? fuse_chan_get(ch) : NULL;
 
        err = EIO;
        if (!se->got_init) {
                enum fuse_opcode expected;
 
                expected = se->cuse_data ? CUSE_INIT : FUSE_INIT;
                if (in->opcode != expected)
                        goto reply_err;
        } else if (in->opcode == FUSE_INIT || in->opcode == CUSE_INIT)
                goto reply_err;
 
        err = EACCES;
        /* Implement -o allow_root */
        if (se->deny_others && in->uid != se->owner && in->uid != 0 &&
                 in->opcode != FUSE_INIT && in->opcode != FUSE_READ &&
                 in->opcode != FUSE_WRITE && in->opcode != FUSE_FSYNC &&
                 in->opcode != FUSE_RELEASE && in->opcode != FUSE_READDIR &&
                 in->opcode != FUSE_FSYNCDIR && in->opcode != FUSE_RELEASEDIR &&
                 in->opcode != FUSE_NOTIFY_REPLY &&
                 in->opcode != FUSE_READDIRPLUS)
                goto reply_err;
 
        err = ENOSYS;
        if (in->opcode >= FUSE_MAXOP || !fuse_ll_ops[in->opcode].func)
                goto reply_err;
        if (in->opcode != FUSE_INTERRUPT) {
                struct fuse_req *intr;
                pthread_mutex_lock(&se->lock);
                intr = check_interrupt(se, req);
                list_add_req(req, &se->list);
                pthread_mutex_unlock(&se->lock);
                if (intr)
                        fuse_reply_err(intr, EAGAIN);
        }
 
        if ((buf->flags & FUSE_BUF_IS_FD) && write_header_size < buf->size &&
            (in->opcode != FUSE_WRITE || !se->op.write_buf) &&
            in->opcode != FUSE_NOTIFY_REPLY) {
                void *newmbuf;
 
                err = ENOMEM;
                newmbuf = realloc(mbuf, buf->size);
                if (newmbuf == NULL)
                        goto reply_err;
                mbuf = newmbuf;
 
                tmpbuf = FUSE_BUFVEC_INIT(buf->size - write_header_size);
                tmpbuf.buf[0].mem = (char *)mbuf + write_header_size;
 
                res = fuse_ll_copy_from_pipe(&tmpbuf, &bufv);
                err = -res;
                if (res < 0)
                        goto reply_err;
 
                in = mbuf;
        }
 
        inarg = (void *) &in[1];
        if (in->opcode == FUSE_WRITE && se->op.write_buf)
                do_write_buf(req, in->nodeid, inarg, buf);
        else if (in->opcode == FUSE_NOTIFY_REPLY)
                do_notify_reply(req, in->nodeid, inarg, buf);
        else
                fuse_ll_ops[in->opcode].func(req, in->nodeid, inarg);
 
out_free:
        free(mbuf);
        return;
 
reply_err:
        fuse_reply_err(req, err);
clear_pipe:
        if (buf->flags & FUSE_BUF_IS_FD)
                fuse_ll_clear_pipe(se);
        goto out_free;
}
 
#define LL_OPTION(n,o,v) \
        { n, offsetof(struct fuse_session, o), v }
 
static const struct fuse_opt fuse_ll_opts[] = {
        LL_OPTION("debug", debug, 1),
        LL_OPTION("-d", debug, 1),
        LL_OPTION("--debug", debug, 1),
        LL_OPTION("allow_root", deny_others, 1),
        FUSE_OPT_END
};
 
void fuse_lowlevel_version(void)
{
        printf("using FUSE kernel interface version %i.%i\n",
               FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
        fuse_mount_version();
}
 
void fuse_lowlevel_help(void)
{
        /* These are not all options, but the ones that are
           potentially of interest to an end-user */
        printf(
"    -o allow_other         allow access by all users\n"
"    -o allow_root          allow access by root\n"
"    -o auto_unmount        auto unmount on process termination\n");
}
 
void fuse_session_destroy(struct fuse_session *se)
{
        struct fuse_ll_pipe *llp;
 
        if (se->got_init && !se->got_destroy) {
                if (se->op.destroy)
                        se->op.destroy(se->userdata);
        }
        llp = pthread_getspecific(se->pipe_key);
        if (llp != NULL)
                fuse_ll_pipe_free(llp);
        pthread_key_delete(se->pipe_key);
        pthread_mutex_destroy(&se->lock);
        free(se->cuse_data);
        if (se->fd != -1)
                close(se->fd);
        destroy_mount_opts(se->mo);
        free(se);
}
 
 
static void fuse_ll_pipe_destructor(void *data)
{
        struct fuse_ll_pipe *llp = data;
        fuse_ll_pipe_free(llp);
}
 
int fuse_session_receive_buf(struct fuse_session *se, struct fuse_buf *buf)
{
        return fuse_session_receive_buf_int(se, buf, NULL);
}
 
int fuse_session_receive_buf_int(struct fuse_session *se, struct fuse_buf *buf,
                                 struct fuse_chan *ch)
{
        int err;
        ssize_t res;
#ifdef HAVE_SPLICE
        size_t bufsize = se->bufsize;
        struct fuse_ll_pipe *llp;
        struct fuse_buf tmpbuf;
 
        if (se->conn.proto_minor < 14 || !(se->conn.want & FUSE_CAP_SPLICE_READ))
                goto fallback;
 
        llp = fuse_ll_get_pipe(se);
        if (llp == NULL)
                goto fallback;
 
        if (llp->size < bufsize) {
                if (llp->can_grow) {
                        res = fcntl(llp->pipe[0], F_SETPIPE_SZ, bufsize);
                        if (res == -1) {
                                llp->can_grow = 0;
                                res = grow_pipe_to_max(llp->pipe[0]);
                                if (res > 0)
                                        llp->size = res;
                                goto fallback;
                        }
                        llp->size = res;
                }
                if (llp->size < bufsize)
                        goto fallback;
        }
 
        res = splice(ch ? ch->fd : se->fd,
                     NULL, llp->pipe[1], NULL, bufsize, 0);
        err = errno;
 
        if (fuse_session_exited(se))
                return 0;
 
        if (res == -1) {
                if (err == ENODEV) {
                        /* Filesystem was unmounted, or connection was aborted
                           via /sys/fs/fuse/connections */
                        fuse_session_exit(se);
                        return 0;
                }
                if (err != EINTR && err != EAGAIN)
                        perror("fuse: splice from device");
                return -err;
        }
 
        if (res < sizeof(struct fuse_in_header)) {
                fuse_log(FUSE_LOG_ERR, "short splice from fuse device\n");
                return -EIO;
        }
 
        tmpbuf = (struct fuse_buf) {
                .size = res,
                .flags = FUSE_BUF_IS_FD,
                .fd = llp->pipe[0],
        };
 
        /*
         * Don't bother with zero copy for small requests.
         * fuse_loop_mt() needs to check for FORGET so this more than
         * just an optimization.
         */
        if (res < sizeof(struct fuse_in_header) +
            sizeof(struct fuse_write_in) + pagesize) {
                struct fuse_bufvec src = { .buf[0] = tmpbuf, .count = 1 };
                struct fuse_bufvec dst = { .count = 1 };
 
                if (!buf->mem) {
                        buf->mem = malloc(se->bufsize);
                        if (!buf->mem) {
                                fuse_log(FUSE_LOG_ERR,
                                        "fuse: failed to allocate read buffer\n");
                                return -ENOMEM;
                        }
                }
                buf->size = se->bufsize;
                buf->flags = 0;
                dst.buf[0] = *buf;
 
                res = fuse_buf_copy(&dst, &src, 0);
                if (res < 0) {
                        fuse_log(FUSE_LOG_ERR, "fuse: copy from pipe: %s\n",
                                strerror(-res));
                        fuse_ll_clear_pipe(se);
                        return res;
                }
                if (res < tmpbuf.size) {
                        fuse_log(FUSE_LOG_ERR, "fuse: copy from pipe: short read\n");
                        fuse_ll_clear_pipe(se);
                        return -EIO;
                }
                assert(res == tmpbuf.size);
 
        } else {
                /* Don't overwrite buf->mem, as that would cause a leak */
                buf->fd = tmpbuf.fd;
                buf->flags = tmpbuf.flags;
        }
        buf->size = tmpbuf.size;
 
        return res;
 
fallback:
#endif
        if (!buf->mem) {
                buf->mem = malloc(se->bufsize);
                if (!buf->mem) {
                        fuse_log(FUSE_LOG_ERR,
                                "fuse: failed to allocate read buffer\n");
                        return -ENOMEM;
                }
        }
 
restart:
        res = read(ch ? ch->fd : se->fd, buf->mem, se->bufsize);
        err = errno;
 
        if (fuse_session_exited(se))
                return 0;
        if (res == -1) {
                /* ENOENT means the operation was interrupted, it's safe
                   to restart */
                if (err == ENOENT)
                        goto restart;
 
                if (err == ENODEV) {
                        /* Filesystem was unmounted, or connection was aborted
                           via /sys/fs/fuse/connections */
                        fuse_session_exit(se);
                        return 0;
                }
                /* Errors occurring during normal operation: EINTR (read
                   interrupted), EAGAIN (nonblocking I/O), ENODEV (filesystem
                   umounted) */
                if (err != EINTR && err != EAGAIN)
                        perror("fuse: reading device");
                return -err;
        }
        if ((size_t) res < sizeof(struct fuse_in_header)) {
                fuse_log(FUSE_LOG_ERR, "short read on fuse device\n");
                return -EIO;
        }
 
        buf->size = res;
 
        return res;
}
 
struct fuse_session *fuse_session_new(struct fuse_args *args,
                                      const struct fuse_lowlevel_ops *op,
                                      size_t op_size, void *userdata)
{
        int err;
        struct fuse_session *se;
        struct mount_opts *mo;
 
        if (sizeof(struct fuse_lowlevel_ops) < op_size) {
                fuse_log(FUSE_LOG_ERR, "fuse: warning: library too old, some operations may not work\n");
                op_size = sizeof(struct fuse_lowlevel_ops);
        }
 
        if (args->argc == 0) {
                fuse_log(FUSE_LOG_ERR, "fuse: empty argv passed to fuse_session_new().\n");
                return NULL;
        }
 
        se = (struct fuse_session *) calloc(1, sizeof(struct fuse_session));
        if (se == NULL) {
                fuse_log(FUSE_LOG_ERR, "fuse: failed to allocate fuse object\n");
                goto out1;
        }
        se->fd = -1;
        se->conn.max_write = UINT_MAX;
        se->conn.max_readahead = UINT_MAX;
 
        /* Parse options */
        if(fuse_opt_parse(args, se, fuse_ll_opts, NULL) == -1)
                goto out2;
        if(se->deny_others) {
                /* Allowing access only by root is done by instructing
                 * kernel to allow access by everyone, and then restricting
                 * access to root and mountpoint owner in libfuse.
                 */
                // We may be adding the option a second time, but
                // that doesn't hurt.
                if(fuse_opt_add_arg(args, "-oallow_other") == -1)
                        goto out2;
        }
        mo = parse_mount_opts(args);
        if (mo == NULL)
                goto out3;
 
        if(args->argc == 1 &&
           args->argv[0][0] == '-') {
                fuse_log(FUSE_LOG_ERR, "fuse: warning: argv[0] looks like an option, but "
                        "will be ignored\n");
        } else if (args->argc != 1) {
                int i;
                fuse_log(FUSE_LOG_ERR, "fuse: unknown option(s): `");
                for(i = 1; i < args->argc-1; i++)
                        fuse_log(FUSE_LOG_ERR, "%s ", args->argv[i]);
                fuse_log(FUSE_LOG_ERR, "%s'\n", args->argv[i]);
                goto out4;
        }
 
        if (se->debug)
                fuse_log(FUSE_LOG_DEBUG, "FUSE library version: %s\n", PACKAGE_VERSION);
 
        se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() +
                FUSE_BUFFER_HEADER_SIZE;
 
        list_init_req(&se->list);
        list_init_req(&se->interrupts);
        list_init_nreq(&se->notify_list);
        se->notify_ctr = 1;
        pthread_mutex_init(&se->lock, NULL);
 
        err = pthread_key_create(&se->pipe_key, fuse_ll_pipe_destructor);
        if (err) {
                fuse_log(FUSE_LOG_ERR, "fuse: failed to create thread specific key: %s\n",
                        strerror(err));
                goto out5;
        }
 
        memcpy(&se->op, op, op_size);
        se->owner = getuid();
        se->userdata = userdata;
 
        se->mo = mo;
        return se;
 
out5:
        pthread_mutex_destroy(&se->lock);
out4:
        fuse_opt_free_args(args);
out3:
        if (mo != NULL)
                destroy_mount_opts(mo);
out2:
        free(se);
out1:
        return NULL;
}
 
int fuse_session_mount(struct fuse_session *se, const char *mountpoint)
{
        int fd;
 
        /*
         * 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);
 
        /*
         * To allow FUSE daemons to run without privileges, the caller may open
         * /dev/fuse before launching the file system and pass on the file
         * descriptor by specifying /dev/fd/N as the mount point. Note that the
         * parent process takes care of performing the mount in this case.
         */
        fd = fuse_mnt_parse_fuse_fd(mountpoint);
        if (fd != -1) {
                if (fcntl(fd, F_GETFD) == -1) {
                        fuse_log(FUSE_LOG_ERR,
                                "fuse: Invalid file descriptor /dev/fd/%u\n",
                                fd);
                        return -1;
                }
                se->fd = fd;
                return 0;
        }
 
        /* Open channel */
        fd = fuse_kern_mount(mountpoint, se->mo);
        if (fd == -1)
                return -1;
        se->fd = fd;
 
        /* Save mountpoint */
        se->mountpoint = strdup(mountpoint);
        if (se->mountpoint == NULL)
                goto error_out;
 
        return 0;
 
error_out:
        fuse_kern_unmount(mountpoint, fd);
        return -1;
}
 
int fuse_session_fd(struct fuse_session *se)
{
        return se->fd;
}
 
void fuse_session_unmount(struct fuse_session *se)
{
        if (se->mountpoint != NULL) {
                fuse_kern_unmount(se->mountpoint, se->fd);
                se->fd = -1;
                free(se->mountpoint);
                se->mountpoint = NULL;
        }
}
 
#ifdef linux
int fuse_req_getgroups(fuse_req_t req, int size, gid_t list[])
{
        char *buf;
        size_t bufsize = 1024;
        char path[128];
        int ret;
        int fd;
        unsigned long pid = req->ctx.pid;
        char *s;
 
        sprintf(path, "/proc/%lu/task/%lu/status", pid, pid);
 
retry:
        buf = malloc(bufsize);
        if (buf == NULL)
                return -ENOMEM;
 
        ret = -EIO;
        fd = open(path, O_RDONLY);
        if (fd == -1)
                goto out_free;
 
        ret = read(fd, buf, bufsize);
        close(fd);
        if (ret < 0) {
                ret = -EIO;
                goto out_free;
        }
 
        if ((size_t)ret == bufsize) {
                free(buf);
                bufsize *= 4;
                goto retry;
        }
 
        ret = -EIO;
        s = strstr(buf, "\nGroups:");
        if (s == NULL)
                goto out_free;
 
        s += 8;
        ret = 0;
        while (1) {
                char *end;
                unsigned long val = strtoul(s, &end, 0);
                if (end == s)
                        break;
 
                s = end;
                if (ret < size)
                        list[ret] = val;
                ret++;
        }
 
out_free:
        free(buf);
        return ret;
}
#else /* linux */
/*
 * This is currently not implemented on other than Linux...
 */
int fuse_req_getgroups(fuse_req_t req, int size, gid_t list[])
{
        (void) req; (void) size; (void) list;
        return -ENOSYS;
}
#endif
 
/* Prevent spurious data race warning - we don't care
 * about races for this flag */
__attribute__((no_sanitize_thread))
void fuse_session_exit(struct fuse_session *se)
{
        se->exited = 1;
}
 
__attribute__((no_sanitize_thread))
void fuse_session_reset(struct fuse_session *se)
{
        se->exited = 0;
        se->error = 0;
}
 
__attribute__((no_sanitize_thread))
int fuse_session_exited(struct fuse_session *se)
{
        return se->exited;
}