qemu

fuse_lowlevel.c (74564B)

---

 /*
  * 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
  */
 
 #include "qemu/osdep.h"
 #include "fuse_i.h"
 #include "standard-headers/linux/fuse.h"
 #include "fuse_misc.h"
 #include "fuse_opt.h"
 #include "fuse_virtio.h"
 
 #include <sys/file.h>
 
 #define THREAD_POOL_SIZE 0
 
 #define OFFSET_MAX 0x7fffffffffffffffLL
 
 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 = (struct fuse_attr){
         .ino = stbuf->st_ino,
         .mode = stbuf->st_mode,
         .nlink = stbuf->st_nlink,
         .uid = stbuf->st_uid,
         .gid = stbuf->st_gid,
         .rdev = stbuf->st_rdev,
         .size = stbuf->st_size,
         .blksize = stbuf->st_blksize,
         .blocks = stbuf->st_blocks,
         .atime = stbuf->st_atime,
         .mtime = stbuf->st_mtime,
         .ctime = stbuf->st_ctime,
         .atimensec = ST_ATIM_NSEC(stbuf),
         .mtimensec = ST_MTIM_NSEC(stbuf),
         .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);
     g_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;
     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 = g_try_new0(struct fuse_req, 1);
     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);
         fuse_mutex_init(&req->lock);
     }
 
     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;
 
     out->len = iov_length(iov, count);
     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);
     }
 
     if (fuse_lowlevel_is_virtio(se)) {
         return virtio_send_msg(se, ch, iov, count);
     }
 
     abort(); /* virtio should have taken it before here */
     return 0;
 }
 
 
 int fuse_send_reply_iov_nofree(fuse_req_t req, int error, struct iovec *iov,
                                int count)
 {
     struct fuse_out_header out = {
         .unique = req->unique,
         .error = error,
     };
 
     if (error <= -1000 || error > 0) {
         fuse_log(FUSE_LOG_ERR, "fuse: bad error value: %i\n", error);
         out.error = -ERANGE;
     }
 
     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;
     g_autofree struct iovec *padded_iov = NULL;
 
     padded_iov = g_try_new(struct iovec, count + 1);
     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);
 
     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 = (struct fuse_kstatfs){
         .bsize = stbuf->f_bsize,
         .frsize = stbuf->f_frsize,
         .blocks = stbuf->f_blocks,
         .bfree = stbuf->f_bfree,
         .bavail = stbuf->f_bavail,
         .files = stbuf->f_files,
         .ffree = stbuf->f_ffree,
         .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 = (struct fuse_entry_out){
         .nodeid = e->ino,
         .generation = e->generation,
         .entry_valid = calc_timeout_sec(e->entry_timeout),
         .entry_valid_nsec = calc_timeout_nsec(e->entry_timeout),
         .attr_valid = calc_timeout_sec(e->attr_timeout),
         .attr_valid_nsec = calc_timeout_nsec(e->attr_timeout),
     };
     convert_stat(&e->attr, &arg->attr);
 
     arg->attr.flags = e->attr_flags;
 }
 
 /*
  * `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 = (struct fuse_dirent){
         .ino = e->attr.st_ino,
         .off = off,
         .namelen = namelen,
         .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 = sizeof(arg);
 
     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 = 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 = 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)
 {
     /* 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);
     }
 
     if (fuse_lowlevel_is_virtio(se) && buf->count == 1 &&
         buf->buf[0].flags == (FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK)) {
         return virtio_send_data_iov(se, ch, iov, iov_count, buf, len);
     }
 
     abort(); /* Will have taken vhost path */
     return 0;
 }
 
 static int fuse_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
                               struct iovec *iov, int iov_count,
                               struct fuse_bufvec *buf)
 {
     size_t len = fuse_buf_size(buf);
 
     return fuse_send_data_iov_fallback(se, ch, iov, iov_count, buf, len);
 }
 
 int fuse_reply_data(fuse_req_t req, struct fuse_bufvec *bufv)
 {
     struct iovec iov[2];
     struct fuse_out_header out = {
         .unique = req->unique,
     };
     int res;
 
     iov[0].iov_base = &out;
     iov[0].iov_len = sizeof(struct fuse_out_header);
 
     res = fuse_send_data_iov(req->se, req->ch, iov, 1, bufv);
     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 = 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 = g_try_new(struct fuse_ioctl_iovec, 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;
     g_autofree struct fuse_ioctl_iovec *in_fiov = NULL;
     g_autofree 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++;
 
     /* Can't handle non-compat 64bit ioctls on 32bit */
     if (sizeof(void *) == 4 && req->ioctl_64bit) {
         res = fuse_reply_err(req, EINVAL);
         return res;
     }
 
     if (in_count) {
         in_fiov = fuse_ioctl_iovec_copy(in_iov, in_count);
         if (!in_fiov) {
             res = fuse_reply_err(req, ENOMEM);
             return res;
         }
 
         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) {
             res = fuse_reply_err(req, ENOMEM);
             return res;
         }
 
         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);
 
     return res;
 }
 
 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)
 {
     g_autofree struct iovec *padded_iov = NULL;
     struct fuse_ioctl_out arg;
     int res;
 
     padded_iov = g_try_new(struct iovec, count + 2);
     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);
 
     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,
                       struct fuse_mbuf_iter *iter)
 {
     const char *name = fuse_mbuf_iter_advance_str(iter);
     if (!name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                       struct fuse_mbuf_iter *iter)
 {
     struct fuse_forget_in *arg;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                             struct fuse_mbuf_iter *iter)
 {
     struct fuse_batch_forget_in *arg;
     struct fuse_forget_data *forgets;
     size_t scount;
 
     (void)nodeid;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_none(req);
         return;
     }
 
     /*
      * Prevent integer overflow.  The compiler emits the following warning
      * unless we use the scount local variable:
      *
      * error: comparison is always false due to limited range of data type
      * [-Werror=type-limits]
      *
      * This may be true on 64-bit hosts but we need this check for 32-bit
      * hosts.
      */
     scount = arg->count;
     if (scount > SIZE_MAX / sizeof(forgets[0])) {
         fuse_reply_none(req);
         return;
     }
 
     forgets = fuse_mbuf_iter_advance(iter, arg->count * sizeof(forgets[0]));
     if (!forgets) {
         fuse_reply_none(req);
         return;
     }
 
     if (req->se->op.forget_multi) {
         req->se->op.forget_multi(req, arg->count, forgets);
     } else if (req->se->op.forget) {
         unsigned int i;
 
         for (i = 0; i < arg->count; 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, forgets[i].ino, forgets[i].nlookup);
         }
         fuse_reply_none(req);
     } else {
         fuse_reply_none(req);
     }
 }
 
 static void do_getattr(fuse_req_t req, fuse_ino_t nodeid,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_file_info *fip = NULL;
     struct fuse_file_info fi;
 
     struct fuse_getattr_in *arg;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                        struct fuse_mbuf_iter *iter)
 {
     if (req->se->op.setattr) {
         struct fuse_setattr_in *arg;
         struct fuse_file_info *fi = NULL;
         struct fuse_file_info fi_store;
         struct stat stbuf;
 
         arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
         if (!arg) {
             fuse_reply_err(req, EINVAL);
             return;
         }
 
         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 | FUSE_SET_ATTR_KILL_SUIDGID;
 
         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,
                       struct fuse_mbuf_iter *iter)
 {
     struct fuse_access_in *arg;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                         struct fuse_mbuf_iter *iter)
 {
     (void)iter;
 
     if (req->se->op.readlink) {
         req->se->op.readlink(req, nodeid);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static int parse_secctx_fill_req(fuse_req_t req, struct fuse_mbuf_iter *iter)
 {
     struct fuse_secctx_header *fsecctx_header;
     struct fuse_secctx *fsecctx;
     const void *secctx;
     const char *name;
 
     fsecctx_header = fuse_mbuf_iter_advance(iter, sizeof(*fsecctx_header));
     if (!fsecctx_header) {
         return -EINVAL;
     }
 
     /*
      * As of now maximum of one security context is supported. It can
      * change in future though.
      */
     if (fsecctx_header->nr_secctx > 1) {
         return -EINVAL;
     }
 
     /* No security context sent. Maybe no LSM supports it */
     if (!fsecctx_header->nr_secctx) {
         return 0;
     }
 
     fsecctx = fuse_mbuf_iter_advance(iter, sizeof(*fsecctx));
     if (!fsecctx) {
         return -EINVAL;
     }
 
     /* struct fsecctx with zero sized context is not expected */
     if (!fsecctx->size) {
         return -EINVAL;
     }
     name = fuse_mbuf_iter_advance_str(iter);
     if (!name) {
         return -EINVAL;
     }
 
     secctx = fuse_mbuf_iter_advance(iter, fsecctx->size);
     if (!secctx) {
         return -EINVAL;
     }
 
     req->secctx.name = name;
     req->secctx.ctx = secctx;
     req->secctx.ctxlen = fsecctx->size;
     return 0;
 }
 
 static void do_mknod(fuse_req_t req, fuse_ino_t nodeid,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_mknod_in *arg;
     const char *name;
     bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
     int err;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     name = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     req->ctx.umask = arg->umask;
 
     if (secctx_enabled) {
         err = parse_secctx_fill_req(req, iter);
         if (err) {
             fuse_reply_err(req, -err);
             return;
         }
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_mkdir_in *arg;
     const char *name;
     bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
     int err;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     name = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     req->ctx.umask = arg->umask;
 
     if (secctx_enabled) {
         err = parse_secctx_fill_req(req, iter);
         if (err) {
             fuse_reply_err(req, err);
             return;
         }
     }
 
     if (req->se->op.mkdir) {
         req->se->op.mkdir(req, nodeid, name, arg->mode);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static void do_unlink(fuse_req_t req, fuse_ino_t nodeid,
                       struct fuse_mbuf_iter *iter)
 {
     const char *name = fuse_mbuf_iter_advance_str(iter);
 
     if (!name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     const char *name = fuse_mbuf_iter_advance_str(iter);
 
     if (!name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                        struct fuse_mbuf_iter *iter)
 {
     const char *name = fuse_mbuf_iter_advance_str(iter);
     const char *linkname = fuse_mbuf_iter_advance_str(iter);
     bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
     int err;
 
     if (!name || !linkname) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     if (secctx_enabled) {
         err = parse_secctx_fill_req(req, iter);
         if (err) {
             fuse_reply_err(req, err);
             return;
         }
     }
 
     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,
                       struct fuse_mbuf_iter *iter)
 {
     struct fuse_rename_in *arg;
     const char *oldname;
     const char *newname;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     oldname = fuse_mbuf_iter_advance_str(iter);
     newname = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !oldname || !newname) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_rename2_in *arg;
     const char *oldname;
     const char *newname;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     oldname = fuse_mbuf_iter_advance_str(iter);
     newname = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !oldname || !newname) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                     struct fuse_mbuf_iter *iter)
 {
     struct fuse_link_in *arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     const char *name = fuse_mbuf_iter_advance_str(iter);
 
     if (!arg || !name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     if (req->se->op.link) {
         req->se->op.link(req, arg->oldnodeid, nodeid, name);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static void do_create(fuse_req_t req, fuse_ino_t nodeid,
                       struct fuse_mbuf_iter *iter)
 {
     bool secctx_enabled = req->se->conn.want & FUSE_CAP_SECURITY_CTX;
 
     if (req->se->op.create) {
         struct fuse_create_in *arg;
         struct fuse_file_info fi;
         const char *name;
 
         arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
         name = fuse_mbuf_iter_advance_str(iter);
         if (!arg || !name) {
             fuse_reply_err(req, EINVAL);
             return;
         }
 
         if (secctx_enabled) {
             int err;
             err = parse_secctx_fill_req(req, iter);
             if (err) {
                 fuse_reply_err(req, err);
                 return;
             }
         }
 
         memset(&fi, 0, sizeof(fi));
         fi.flags = arg->flags;
         fi.kill_priv = arg->open_flags & FUSE_OPEN_KILL_SUIDGID;
 
         req->ctx.umask = arg->umask;
 
         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,
                     struct fuse_mbuf_iter *iter)
 {
     struct fuse_open_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     /* File creation is handled by do_create() or do_mknod() */
     if (arg->flags & (O_CREAT | O_TMPFILE)) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     memset(&fi, 0, sizeof(fi));
     fi.flags = arg->flags;
     fi.kill_priv = arg->open_flags & FUSE_OPEN_KILL_SUIDGID;
 
     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,
                     struct fuse_mbuf_iter *iter)
 {
     if (req->se->op.read) {
         struct fuse_read_in *arg;
         struct fuse_file_info fi;
 
         arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
         if (!arg) {
             fuse_reply_err(req, EINVAL);
             return;
         }
 
         memset(&fi, 0, sizeof(fi));
         fi.fh = arg->fh;
         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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_write_in *arg;
     struct fuse_file_info fi;
     const char *param;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     param = fuse_mbuf_iter_advance(iter, arg->size);
     if (!param) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     memset(&fi, 0, sizeof(fi));
     fi.fh = arg->fh;
     fi.writepage = (arg->write_flags & FUSE_WRITE_CACHE) != 0;
     fi.kill_priv = !!(arg->write_flags & FUSE_WRITE_KILL_PRIV);
 
     fi.lock_owner = arg->lock_owner;
     fi.flags = arg->flags;
 
     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,
                          struct fuse_mbuf_iter *iter, struct fuse_bufvec *ibufv)
 {
     struct fuse_session *se = req->se;
     struct fuse_bufvec *pbufv = ibufv;
     struct fuse_bufvec tmpbufv = {
         .buf[0] = ibufv->buf[0],
         .count = 1,
     };
     struct fuse_write_in *arg;
     size_t arg_size = sizeof(*arg);
     struct fuse_file_info fi;
 
     memset(&fi, 0, sizeof(fi));
 
     arg = fuse_mbuf_iter_advance(iter, arg_size);
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     fi.lock_owner = arg->lock_owner;
     fi.flags = arg->flags;
     fi.fh = arg->fh;
     fi.writepage = !!(arg->write_flags & FUSE_WRITE_CACHE);
     fi.kill_priv = !!(arg->write_flags & FUSE_WRITE_KILL_PRIV);
 
     if (ibufv->count == 1) {
         assert(!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD));
         tmpbufv.buf[0].mem = ((char *)arg) + arg_size;
         tmpbufv.buf[0].size -= sizeof(struct fuse_in_header) + arg_size;
         pbufv = &tmpbufv;
     } else {
         /*
          *  Input bufv contains the headers in the first element
          * and the data in the rest, we need to skip that first element
          */
         ibufv->buf[0].size = 0;
     }
 
     if (fuse_buf_size(pbufv) != arg->size) {
         fuse_log(FUSE_LOG_ERR,
                  "fuse: do_write_buf: buffer size doesn't match arg->size\n");
         fuse_reply_err(req, EIO);
         return;
     }
 
     se->op.write_buf(req, nodeid, pbufv, arg->offset, &fi);
 }
 
 static void do_flush(fuse_req_t req, fuse_ino_t nodeid,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_flush_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     memset(&fi, 0, sizeof(fi));
     fi.fh = arg->fh;
     fi.flush = 1;
     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,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_release_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     memset(&fi, 0, sizeof(fi));
     fi.flags = arg->flags;
     fi.fh = arg->fh;
     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;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_fsync_in *arg;
     struct fuse_file_info fi;
     int datasync;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
     datasync = arg->fsync_flags & 1;
 
     memset(&fi, 0, sizeof(fi));
     fi.fh = arg->fh;
 
     if (req->se->op.fsync) {
         if (fi.fh == (uint64_t)-1) {
             req->se->op.fsync(req, nodeid, datasync, NULL);
         } else {
             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,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_open_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_read_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                            struct fuse_mbuf_iter *iter)
 {
     struct fuse_read_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                           struct fuse_mbuf_iter *iter)
 {
     struct fuse_release_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                         struct fuse_mbuf_iter *iter)
 {
     struct fuse_fsync_in *arg;
     struct fuse_file_info fi;
     int datasync;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
     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,
                       struct fuse_mbuf_iter *iter)
 {
     (void)nodeid;
     (void)iter;
 
     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,
                         struct fuse_mbuf_iter *iter)
 {
     struct fuse_setxattr_in *arg;
     const char *name;
     const char *value;
     bool setxattr_ext = req->se->conn.want & FUSE_CAP_SETXATTR_EXT;
 
     if (setxattr_ext) {
         arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     } else {
         arg = fuse_mbuf_iter_advance(iter, FUSE_COMPAT_SETXATTR_IN_SIZE);
     }
     name = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     value = fuse_mbuf_iter_advance(iter, arg->size);
     if (!value) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     if (req->se->op.setxattr) {
         uint32_t setxattr_flags = setxattr_ext ? arg->setxattr_flags : 0;
         req->se->op.setxattr(req, nodeid, name, value, arg->size, arg->flags,
                              setxattr_flags);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static void do_getxattr(fuse_req_t req, fuse_ino_t nodeid,
                         struct fuse_mbuf_iter *iter)
 {
     struct fuse_getxattr_in *arg;
     const char *name;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     name = fuse_mbuf_iter_advance_str(iter);
     if (!arg || !name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     if (req->se->op.getxattr) {
         req->se->op.getxattr(req, nodeid, name, arg->size);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static void do_listxattr(fuse_req_t req, fuse_ino_t nodeid,
                          struct fuse_mbuf_iter *iter)
 {
     struct fuse_getxattr_in *arg;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                            struct fuse_mbuf_iter *iter)
 {
     const char *name = fuse_mbuf_iter_advance_str(iter);
 
     if (!name) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_lk_in *arg;
     struct fuse_file_info fi;
     struct flock flock;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                             struct fuse_mbuf_iter *iter, int sleep)
 {
     struct fuse_lk_in *arg;
     struct fuse_file_info fi;
     struct flock flock;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     do_setlk_common(req, nodeid, iter, 0);
 }
 
 static void do_setlkw(fuse_req_t req, fuse_ino_t nodeid,
                       struct fuse_mbuf_iter *iter)
 {
     do_setlk_common(req, nodeid, iter, 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,
                          struct fuse_mbuf_iter *iter)
 {
     struct fuse_interrupt_in *arg;
     struct fuse_session *se = req->se;
 
     (void)nodeid;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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);
             g_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,
                     struct fuse_mbuf_iter *iter)
 {
     struct fuse_bmap_in *arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
 
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_ioctl_in *arg;
     unsigned int flags;
     void *in_buf = NULL;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     flags = arg->flags;
     if (flags & FUSE_IOCTL_DIR && !(req->se->conn.want & FUSE_CAP_IOCTL_DIR)) {
         fuse_reply_err(req, ENOTTY);
         return;
     }
 
     if (arg->in_size) {
         in_buf = fuse_mbuf_iter_advance(iter, arg->in_size);
         if (!in_buf) {
             fuse_reply_err(req, EINVAL);
             return;
         }
     }
 
     memset(&fi, 0, sizeof(fi));
     fi.fh = arg->fh;
 
     if (sizeof(void *) == 4 && !(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,
                     struct fuse_mbuf_iter *iter)
 {
     struct fuse_poll_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                          struct fuse_mbuf_iter *iter)
 {
     struct fuse_fallocate_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                                struct fuse_mbuf_iter *iter)
 {
     struct fuse_copy_file_range_in *arg;
     struct fuse_file_info fi_in, fi_out;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     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,
                      struct fuse_mbuf_iter *iter)
 {
     struct fuse_lseek_in *arg;
     struct fuse_file_info fi;
 
     arg = fuse_mbuf_iter_advance(iter, sizeof(*arg));
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
     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);
     }
 }
 
 static void do_syncfs(fuse_req_t req, fuse_ino_t nodeid,
                       struct fuse_mbuf_iter *iter)
 {
     if (req->se->op.syncfs) {
         req->se->op.syncfs(req, nodeid);
     } else {
         fuse_reply_err(req, ENOSYS);
     }
 }
 
 static void do_init(fuse_req_t req, fuse_ino_t nodeid,
                     struct fuse_mbuf_iter *iter)
 {
     size_t compat_size = offsetof(struct fuse_init_in, max_readahead);
     size_t compat2_size = offsetof(struct fuse_init_in, flags) +
                               sizeof(uint32_t);
     /* Fuse structure extended with minor version 36 */
     size_t compat3_size = endof(struct fuse_init_in, unused);
     struct fuse_init_in *arg;
     struct fuse_init_out outarg;
     struct fuse_session *se = req->se;
     size_t bufsize = se->bufsize;
     size_t outargsize = sizeof(outarg);
     uint64_t flags = 0;
 
     (void)nodeid;
 
     /* First consume the old fields... */
     arg = fuse_mbuf_iter_advance(iter, compat_size);
     if (!arg) {
         fuse_reply_err(req, EINVAL);
         return;
     }
 
     /* ...and now consume the new fields. */
     if (arg->major == 7 && arg->minor >= 6) {
         if (!fuse_mbuf_iter_advance(iter, compat2_size - compat_size)) {
             fuse_reply_err(req, EINVAL);
             return;
         }
         flags |= arg->flags;
     }
 
     /*
      * fuse_init_in was extended again with minor version 36. Just read
      * current known size of fuse_init so that future extension and
      * header rebase does not cause breakage.
      */
     if (sizeof(*arg) > compat2_size && (arg->flags & FUSE_INIT_EXT)) {
         if (!fuse_mbuf_iter_advance(iter, compat3_size - compat2_size)) {
             fuse_reply_err(req, EINVAL);
             return;
         }
         flags |= (uint64_t) arg->flags2 << 32;
     }
 
     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%016" PRIx64 "\n", 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 || (arg->major == 7 && arg->minor < 31)) {
         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->max_readahead < se->conn.max_readahead) {
         se->conn.max_readahead = arg->max_readahead;
     }
     if (flags & FUSE_ASYNC_READ) {
         se->conn.capable |= FUSE_CAP_ASYNC_READ;
     }
     if (flags & FUSE_POSIX_LOCKS) {
         se->conn.capable |= FUSE_CAP_POSIX_LOCKS;
     }
     if (flags & FUSE_ATOMIC_O_TRUNC) {
         se->conn.capable |= FUSE_CAP_ATOMIC_O_TRUNC;
     }
     if (flags & FUSE_EXPORT_SUPPORT) {
         se->conn.capable |= FUSE_CAP_EXPORT_SUPPORT;
     }
     if (flags & FUSE_DONT_MASK) {
         se->conn.capable |= FUSE_CAP_DONT_MASK;
     }
     if (flags & FUSE_FLOCK_LOCKS) {
         se->conn.capable |= FUSE_CAP_FLOCK_LOCKS;
     }
     if (flags & FUSE_AUTO_INVAL_DATA) {
         se->conn.capable |= FUSE_CAP_AUTO_INVAL_DATA;
     }
     if (flags & FUSE_DO_READDIRPLUS) {
         se->conn.capable |= FUSE_CAP_READDIRPLUS;
     }
     if (flags & FUSE_READDIRPLUS_AUTO) {
         se->conn.capable |= FUSE_CAP_READDIRPLUS_AUTO;
     }
     if (flags & FUSE_ASYNC_DIO) {
         se->conn.capable |= FUSE_CAP_ASYNC_DIO;
     }
     if (flags & FUSE_WRITEBACK_CACHE) {
         se->conn.capable |= FUSE_CAP_WRITEBACK_CACHE;
     }
     if (flags & FUSE_NO_OPEN_SUPPORT) {
         se->conn.capable |= FUSE_CAP_NO_OPEN_SUPPORT;
     }
     if (flags & FUSE_PARALLEL_DIROPS) {
         se->conn.capable |= FUSE_CAP_PARALLEL_DIROPS;
     }
     if (flags & FUSE_POSIX_ACL) {
         se->conn.capable |= FUSE_CAP_POSIX_ACL;
     }
     if (flags & FUSE_HANDLE_KILLPRIV) {
         se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV;
     }
     if (flags & FUSE_NO_OPENDIR_SUPPORT) {
         se->conn.capable |= FUSE_CAP_NO_OPENDIR_SUPPORT;
     }
     if (!(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;
         }
     }
     if (flags & FUSE_SUBMOUNTS) {
         se->conn.capable |= FUSE_CAP_SUBMOUNTS;
     }
     if (flags & FUSE_HANDLE_KILLPRIV_V2) {
         se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV_V2;
     }
     if (flags & FUSE_SETXATTR_EXT) {
         se->conn.capable |= FUSE_CAP_SETXATTR_EXT;
     }
     if (flags & FUSE_SECURITY_CTX) {
         se->conn.capable |= FUSE_CAP_SECURITY_CTX;
     }
 #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
     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;
     se->got_destroy = 0;
     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%" PRIx64 " 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;
     }
 
     if (se->conn.max_write < bufsize - FUSE_BUFFER_HEADER_SIZE) {
         se->bufsize = se->conn.max_write + FUSE_BUFFER_HEADER_SIZE;
     }
     if (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_PARALLEL_DIROPS) {
         outarg.flags |= FUSE_PARALLEL_DIROPS;
     }
     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;
     }
     outarg.max_readahead = se->conn.max_readahead;
     outarg.max_write = se->conn.max_write;
     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;
     outarg.time_gran = se->conn.time_gran;
 
     if (se->conn.want & FUSE_CAP_HANDLE_KILLPRIV_V2) {
         outarg.flags |= FUSE_HANDLE_KILLPRIV_V2;
     }
 
     if (se->conn.want & FUSE_CAP_SETXATTR_EXT) {
         outarg.flags |= FUSE_SETXATTR_EXT;
     }
 
     if (se->conn.want & FUSE_CAP_SECURITY_CTX) {
         /* bits 32..63 get shifted down 32 bits into the flags2 field */
         outarg.flags2 |= FUSE_SECURITY_CTX >> 32;
     }
 
     fuse_log(FUSE_LOG_DEBUG, "   INIT: %u.%u\n", outarg.major, outarg.minor);
     fuse_log(FUSE_LOG_DEBUG, "   flags2=0x%08x flags=0x%08x\n", outarg.flags2,
              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);
 
     send_reply_ok(req, &outarg, outargsize);
 }
 
 static void do_destroy(fuse_req_t req, fuse_ino_t nodeid,
                        struct fuse_mbuf_iter *iter)
 {
     struct fuse_session *se = req->se;
 
     (void)nodeid;
     (void)iter;
 
     se->got_destroy = 1;
     se->got_init = 0;
     if (se->op.destroy) {
         se->op.destroy(se->userdata);
     }
 
     send_reply_ok(req, NULL, 0);
 }
 
 int fuse_lowlevel_notify_store(struct fuse_session *se, fuse_ino_t ino,
                                off_t offset, struct fuse_bufvec *bufv)
 {
     struct fuse_out_header out = {
         .error = FUSE_NOTIFY_STORE,
     };
     struct fuse_notify_store_out outarg = {
         .nodeid = ino,
         .offset = offset,
         .size = fuse_buf_size(bufv),
     };
     struct iovec iov[3];
     int res;
 
     if (!se) {
         return -EINVAL;
     }
 
     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);
     if (res > 0) {
         res = -res;
     }
 
     return res;
 }
 
 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, struct fuse_mbuf_iter *);
     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] = { NULL, "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" },
     [FUSE_SYNCFS] = { do_syncfs, "SYNCFS" },
 };
 
 #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;
     }
 }
 
 void fuse_session_process_buf(struct fuse_session *se,
                               const struct fuse_buf *buf)
 {
     struct fuse_bufvec bufv = { .buf[0] = *buf, .count = 1 };
     fuse_session_process_buf_int(se, &bufv, NULL);
 }
 
 /*
  * Restriction:
  *   bufv is normally a single entry buffer, except for a write
  *   where (if it's in memory) then the bufv may be multiple entries,
  *   where the first entry contains all headers and subsequent entries
  *   contain data
  *   bufv shall not use any offsets etc to make the data anything
  *   other than contiguous starting from 0.
  */
 void fuse_session_process_buf_int(struct fuse_session *se,
                                   struct fuse_bufvec *bufv,
                                   struct fuse_chan *ch)
 {
     const struct fuse_buf *buf = bufv->buf;
     struct fuse_mbuf_iter iter = FUSE_MBUF_ITER_INIT(buf);
     struct fuse_in_header *in;
     struct fuse_req *req;
     int err;
 
     /* The first buffer must be a memory buffer */
     assert(!(buf->flags & FUSE_BUF_IS_FD));
 
     in = fuse_mbuf_iter_advance(&iter, sizeof(*in));
     assert(in); /* caller guarantees the input buffer is large enough */
 
     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);
         return;
     }
 
     req->unique = in->unique;
     req->ctx.uid = in->uid;
     req->ctx.gid = in->gid;
     req->ctx.pid = in->pid;
     req->ch = ch;
 
     /*
      * INIT and DESTROY requests are serialized, all other request types
      * run in parallel.  This prevents races between FUSE_INIT and ordinary
      * requests, FUSE_INIT and FUSE_INIT, FUSE_INIT and FUSE_DESTROY, and
      * FUSE_DESTROY and FUSE_DESTROY.
      */
     if (in->opcode == FUSE_INIT || in->opcode == CUSE_INIT ||
         in->opcode == FUSE_DESTROY) {
         pthread_rwlock_wrlock(&se->init_rwlock);
     } else {
         pthread_rwlock_rdlock(&se->init_rwlock);
     }
 
     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) {
         if (fuse_lowlevel_is_virtio(se)) {
             /*
              * TODO: This is after a hard reboot typically, we need to do
              * a destroy, but we can't reply to this request yet so
              * we can't use do_destroy
              */
             fuse_log(FUSE_LOG_DEBUG, "%s: reinit\n", __func__);
             se->got_destroy = 1;
             se->got_init = 0;
             if (se->op.destroy) {
                 se->op.destroy(se->userdata);
             }
         } else {
             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 (in->opcode == FUSE_WRITE && se->op.write_buf) {
         do_write_buf(req, in->nodeid, &iter, bufv);
     } else {
         fuse_ll_ops[in->opcode].func(req, in->nodeid, &iter);
     }
 
     pthread_rwlock_unlock(&se->init_rwlock);
     return;
 
 reply_err:
     fuse_reply_err(req, err);
     pthread_rwlock_unlock(&se->init_rwlock);
 }
 
 #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),
     LL_OPTION("--socket-path=%s", vu_socket_path, 0),
     LL_OPTION("--socket-group=%s", vu_socket_group, 0),
     LL_OPTION("--fd=%d", vu_listen_fd, 0),
     LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
     FUSE_OPT_END
 };
 
 void fuse_lowlevel_version(void)
 {
     printf("using FUSE kernel interface version %i.%i\n", FUSE_KERNEL_VERSION,
            FUSE_KERNEL_MINOR_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_root              allow access by root\n"
         "    --socket-path=PATH         path for the vhost-user socket\n"
         "    --socket-group=GRNAME      name of group for the vhost-user socket\n"
         "    --fd=FDNUM                 fd number of vhost-user socket\n"
         "    --thread-pool-size=NUM     thread pool size limit (default %d)\n",
         THREAD_POOL_SIZE);
 }
 
 void fuse_session_destroy(struct fuse_session *se)
 {
     if (se->got_init && !se->got_destroy) {
         if (se->op.destroy) {
             se->op.destroy(se->userdata);
         }
     }
     pthread_rwlock_destroy(&se->init_rwlock);
     pthread_mutex_destroy(&se->lock);
     free(se->cuse_data);
     if (se->fd != -1) {
         close(se->fd);
     }
 
     if (fuse_lowlevel_is_virtio(se)) {
         virtio_session_close(se);
     }
 
     free(se->vu_socket_path);
     se->vu_socket_path = NULL;
 
     g_free(se);
 }
 
 
 struct fuse_session *fuse_session_new(struct fuse_args *args,
                                       const struct fuse_lowlevel_ops *op,
                                       size_t op_size, void *userdata)
 {
     struct fuse_session *se;
 
     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 = g_try_new0(struct fuse_session, 1);
     if (se == NULL) {
         fuse_log(FUSE_LOG_ERR, "fuse: failed to allocate fuse object\n");
         goto out1;
     }
     se->fd = -1;
     se->vu_listen_fd = -1;
     se->thread_pool_size = THREAD_POOL_SIZE;
     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 (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->vu_socket_path && se->vu_listen_fd < 0) {
         fuse_log(FUSE_LOG_ERR, "fuse: missing --socket-path or --fd option\n");
         goto out4;
     }
     if (se->vu_socket_path && se->vu_listen_fd >= 0) {
         fuse_log(FUSE_LOG_ERR,
                  "fuse: --socket-path and --fd cannot be given together\n");
         goto out4;
     }
     if (se->vu_socket_group && !se->vu_socket_path) {
         fuse_log(FUSE_LOG_ERR,
                  "fuse: --socket-group can only be used with --socket-path\n");
         goto out4;
     }
 
     se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
 
     list_init_req(&se->list);
     list_init_req(&se->interrupts);
     fuse_mutex_init(&se->lock);
     pthread_rwlock_init(&se->init_rwlock, NULL);
 
     memcpy(&se->op, op, op_size);
     se->owner = getuid();
     se->userdata = userdata;
 
     return se;
 
 out4:
     fuse_opt_free_args(args);
 out2:
     g_free(se);
 out1:
     return NULL;
 }
 
 int fuse_session_mount(struct fuse_session *se)
 {
     return virtio_session_mount(se);
 }
 
 int fuse_session_fd(struct fuse_session *se)
 {
     return se->fd;
 }
 
 void fuse_session_unmount(struct fuse_session *se)
 {
 }
 
 int fuse_lowlevel_is_virtio(struct fuse_session *se)
 {
     return !!se->virtio_dev;
 }
 
 void fuse_session_exit(struct fuse_session *se)
 {
     se->exited = 1;
 }
 
 void fuse_session_reset(struct fuse_session *se)
 {
     se->exited = 0;
     se->error = 0;
 }
 
 int fuse_session_exited(struct fuse_session *se)
 {
     return se->exited;
 }