source: FTPfs/sshfs-fuse-1.9/sshfs.c @ 19

/*
  SSH file system
  Copyright (C) 2004  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "config.h"

#include <fuse.h>
#include <fuse_opt.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <semaphore.h>
#include <pthread.h>
#include <netdb.h>
#include <signal.h>
#include <sys/uio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <glib.h>

#include "cache.h"

#if FUSE_VERSION >= 23
#define SSHFS_USE_INIT
#endif

#define SSH_FXP_INIT                1
#define SSH_FXP_VERSION             2
#define SSH_FXP_OPEN                3
#define SSH_FXP_CLOSE               4
#define SSH_FXP_READ                5
#define SSH_FXP_WRITE               6
#define SSH_FXP_LSTAT               7
#define SSH_FXP_FSTAT               8
#define SSH_FXP_SETSTAT             9
#define SSH_FXP_FSETSTAT           10
#define SSH_FXP_OPENDIR            11
#define SSH_FXP_READDIR            12
#define SSH_FXP_REMOVE             13
#define SSH_FXP_MKDIR              14
#define SSH_FXP_RMDIR              15
#define SSH_FXP_REALPATH           16
#define SSH_FXP_STAT               17
#define SSH_FXP_RENAME             18
#define SSH_FXP_READLINK           19
#define SSH_FXP_SYMLINK            20
#define SSH_FXP_STATUS            101
#define SSH_FXP_HANDLE            102
#define SSH_FXP_DATA              103
#define SSH_FXP_NAME              104
#define SSH_FXP_ATTRS             105
#define SSH_FXP_EXTENDED          200
#define SSH_FXP_EXTENDED_REPLY    201

#define SSH_FILEXFER_ATTR_SIZE          0x00000001
#define SSH_FILEXFER_ATTR_UIDGID        0x00000002
#define SSH_FILEXFER_ATTR_PERMISSIONS   0x00000004
#define SSH_FILEXFER_ATTR_ACMODTIME     0x00000008
#define SSH_FILEXFER_ATTR_EXTENDED      0x80000000

#define SSH_FX_OK                            0
#define SSH_FX_EOF                           1
#define SSH_FX_NO_SUCH_FILE                  2
#define SSH_FX_PERMISSION_DENIED             3
#define SSH_FX_FAILURE                       4
#define SSH_FX_BAD_MESSAGE                   5
#define SSH_FX_NO_CONNECTION                 6
#define SSH_FX_CONNECTION_LOST               7
#define SSH_FX_OP_UNSUPPORTED                8

#define SSH_FXF_READ            0x00000001
#define SSH_FXF_WRITE           0x00000002
#define SSH_FXF_APPEND          0x00000004
#define SSH_FXF_CREAT           0x00000008
#define SSH_FXF_TRUNC           0x00000010
#define SSH_FXF_EXCL            0x00000020

#define PROTO_VERSION 3

#define MY_EOF 1

#define MAX_REPLY_LEN (1 << 17)

#define RENAME_TEMP_CHARS 8

#define SFTP_SERVER_PATH "/usr/lib/sftp-server"

#define SSHNODELAY_SO "sshnodelay.so"

struct buffer {
  uint8_t *p;
  size_t len;
  size_t size;
};

struct list_head {
  struct list_head *prev;
  struct list_head *next;
};

struct request;
typedef void (*request_func)(struct request *);

struct request {
  unsigned int want_reply;
  sem_t ready;
  uint8_t reply_type;
  int replied;
  int error;
  struct buffer reply;
  struct timeval start;
  void *data;
  request_func end_func;
  size_t len;
  struct list_head list;
};

struct read_chunk {
  sem_t ready;
  off_t offset;
  size_t size;
  struct buffer data;
  int refs;
  int res;
  long modifver;
};

struct sshfs_file {
  struct buffer handle;
  struct list_head write_reqs;
  pthread_cond_t write_finished;
  int write_error;
  struct read_chunk *readahead;
  off_t next_pos;
  int is_seq;
  int connver;
  int modifver;
  int refs;
};

struct sshfs {
  char *directport;
  char *ssh_command;
  char *sftp_server;
  struct fuse_args ssh_args;
  char *workarounds;
  int rename_workaround;
  int nodelay_workaround;
  int nodelaysrv_workaround;
  int truncate_workaround;
  int buflimit_workaround;
  int transform_symlinks;
  int follow_symlinks;
  int no_check_root;
  int detect_uid;
  unsigned max_read;
  unsigned ssh_ver;
  int sync_write;
  int sync_read;
  int debug;
  int reconnect;
  char *host;
  char *base_path;
  GHashTable *reqtab;
  pthread_mutex_t lock;
  pthread_mutex_t lock_write;
  int processing_thread_started;
  unsigned int randseed;
  int fd;
  int connver;
  int server_version;
  unsigned remote_uid;
  unsigned local_uid;
  int remote_uid_detected;
  unsigned blksize;
  char *progname;
  long modifver;
  unsigned outstanding_len;
  unsigned max_outstanding_len;
  pthread_cond_t outstanding_cond;
};

static struct sshfs sshfs;

static const char *ssh_opts[] = {
  "AddressFamily",
  "BatchMode",
  "BindAddress",
  "ChallengeResponseAuthentication",
  "CheckHostIP",
  "Cipher",
  "Ciphers",
  "Compression",
  "CompressionLevel",
  "ConnectionAttempts",
  "ConnectTimeout",
  "GlobalKnownHostsFile",
  "GSSAPIAuthentication",
  "GSSAPIDelegateCredentials",
  "HostbasedAuthentication",
  "HostKeyAlgorithms",
  "HostKeyAlias",
  "HostName",
  "IdentityFile",
  "IdentitiesOnly",
  "LogLevel",
  "MACs",
  "NoHostAuthenticationForLocalhost",
  "NumberOfPasswordPrompts",
  "PasswordAuthentication",
  "Port",
  "PreferredAuthentications",
  "ProxyCommand",
  "PubkeyAuthentication",
  "RhostsRSAAuthentication",
  "RSAAuthentication",
  "ServerAliveInterval",
  "ServerAliveCountMax",
  "SmartcardDevice",
  "StrictHostKeyChecking",
  "TCPKeepAlive",
  "UsePrivilegedPort",
  "UserKnownHostsFile",
  "VerifyHostKeyDNS",
  NULL,
};

enum {
  KEY_PORT,
  KEY_COMPRESS,
  KEY_HELP,
  KEY_VERSION,
};

#define SSHFS_OPT(t, p, v) { t, offsetof(struct sshfs, p), v }

static struct fuse_opt sshfs_opts[] = {
  SSHFS_OPT("directport=%s",     directport, 0),
  SSHFS_OPT("ssh_command=%s",    ssh_command, 0),
  SSHFS_OPT("sftp_server=%s",    sftp_server, 0),
  SSHFS_OPT("max_read=%u",       max_read, 0),
  SSHFS_OPT("ssh_protocol=%u",   ssh_ver, 0),
  SSHFS_OPT("-1",                ssh_ver, 1),
  SSHFS_OPT("workaround=%s",     workarounds, 0),
  SSHFS_OPT("idmap=none",        detect_uid, 0),
  SSHFS_OPT("idmap=user",        detect_uid, 1),
  SSHFS_OPT("sshfs_sync",        sync_write, 1),
  SSHFS_OPT("no_readahead",      sync_read, 1),
  SSHFS_OPT("sshfs_debug",       debug, 1),
  SSHFS_OPT("reconnect",         reconnect, 1),
  SSHFS_OPT("transform_symlinks", transform_symlinks, 1),
  SSHFS_OPT("follow_symlinks",   follow_symlinks, 1),
  SSHFS_OPT("no_check_root",     no_check_root, 1),

  FUSE_OPT_KEY("-p ",            KEY_PORT),
  FUSE_OPT_KEY("-C",             KEY_COMPRESS),
  FUSE_OPT_KEY("-V",             KEY_VERSION),
  FUSE_OPT_KEY("--version",      KEY_VERSION),
  FUSE_OPT_KEY("-h",             KEY_HELP),
  FUSE_OPT_KEY("--help",         KEY_HELP),
  FUSE_OPT_END
};

static struct fuse_opt workaround_opts[] = {
  SSHFS_OPT("none",       rename_workaround, 0),
  SSHFS_OPT("none",       nodelay_workaround, 0),
  SSHFS_OPT("none",       nodelaysrv_workaround, 0),
  SSHFS_OPT("none",       truncate_workaround, 0),
  SSHFS_OPT("none",       buflimit_workaround, 0),
  SSHFS_OPT("all",        rename_workaround, 1),
  SSHFS_OPT("all",        nodelay_workaround, 1),
  SSHFS_OPT("all",        nodelaysrv_workaround, 1),
  SSHFS_OPT("all",        truncate_workaround, 1),
  SSHFS_OPT("all",        buflimit_workaround, 1),
  SSHFS_OPT("rename",     rename_workaround, 1),
  SSHFS_OPT("norename",   rename_workaround, 0),
  SSHFS_OPT("nodelay",    nodelay_workaround, 1),
  SSHFS_OPT("nonodelay",  nodelay_workaround, 0),
  SSHFS_OPT("nodelaysrv", nodelaysrv_workaround, 1),
  SSHFS_OPT("nonodelaysrv", nodelaysrv_workaround, 0),
  SSHFS_OPT("truncate",   truncate_workaround, 1),
  SSHFS_OPT("notruncate", truncate_workaround, 0),
  SSHFS_OPT("buflimit",   buflimit_workaround, 1),
  SSHFS_OPT("nobuflimit", buflimit_workaround, 0),
  FUSE_OPT_END
};

#define DEBUG(format, args...)            \
  do { if (sshfs.debug) fprintf(stderr, format, args); } while(0)

static const char *type_name(uint8_t type)
{
  switch(type) {
  case SSH_FXP_INIT:           return "INIT";
  case SSH_FXP_VERSION:        return "VERSION";
  case SSH_FXP_OPEN:           return "OPEN";
  case SSH_FXP_CLOSE:          return "CLOSE";
  case SSH_FXP_READ:           return "READ";
  case SSH_FXP_WRITE:          return "WRITE";
  case SSH_FXP_LSTAT:          return "LSTAT";
  case SSH_FXP_FSTAT:          return "FSTAT";
  case SSH_FXP_SETSTAT:        return "SETSTAT";
  case SSH_FXP_FSETSTAT:       return "FSETSTAT";
  case SSH_FXP_OPENDIR:        return "OPENDIR";
  case SSH_FXP_READDIR:        return "READDIR";
  case SSH_FXP_REMOVE:         return "REMOVE";
  case SSH_FXP_MKDIR:          return "MKDIR";
  case SSH_FXP_RMDIR:          return "RMDIR";
  case SSH_FXP_REALPATH:       return "REALPATH";
  case SSH_FXP_STAT:           return "STAT";
  case SSH_FXP_RENAME:         return "RENAME";
  case SSH_FXP_READLINK:       return "READLINK";
  case SSH_FXP_SYMLINK:        return "SYMLINK";
  case SSH_FXP_STATUS:         return "STATUS";
  case SSH_FXP_HANDLE:         return "HANDLE";
  case SSH_FXP_DATA:           return "DATA";
  case SSH_FXP_NAME:           return "NAME";
  case SSH_FXP_ATTRS:          return "ATTRS";
  case SSH_FXP_EXTENDED:       return "EXTENDED";
  case SSH_FXP_EXTENDED_REPLY: return "EXTENDED_REPLY";
  default:                     return "???";
  }
}

#define container_of(ptr, type, member) ({        \
      const typeof( ((type *)0)->member ) *__mptr = (ptr); \
      (type *)( (char *)__mptr - offsetof(type,member) );})

#define list_entry(ptr, type, member)   \
  container_of(ptr, type, member)

static void list_init(struct list_head *head)
{
  head->next = head;
  head->prev = head;
}

static void list_add(struct list_head *new, struct list_head *head)
{
  struct list_head *prev = head;
  struct list_head *next = head->next;
  next->prev = new;
  new->next = next;
  new->prev = prev;
  prev->next = new;
}

static void list_del(struct list_head *entry)
{
  struct list_head *prev = entry->prev;
  struct list_head *next = entry->next;
  next->prev = prev;
  prev->next = next;

}

static int list_empty(const struct list_head *head)
{
  return head->next == head;
}

static inline void buf_init(struct buffer *buf, size_t size)
{
  if (size) {
    buf->p = (uint8_t *) malloc(size);
    if (!buf->p) {
      fprintf(stderr, "sshfs: memory allocation failed\n");
      abort();
    }
  } else
    buf->p = NULL;
  buf->len = 0;
  buf->size = size;
}

static inline void buf_free(struct buffer *buf)
{
  free(buf->p);
}

static inline void buf_finish(struct buffer *buf)
{
  buf->len = buf->size;
}

static inline void buf_clear(struct buffer *buf)
{
  buf_free(buf);
  buf_init(buf, 0);
}

static void buf_resize(struct buffer *buf, size_t len)
{
  buf->size = (buf->len + len + 63) & ~31;
  buf->p = (uint8_t *) realloc(buf->p, buf->size);
  if (!buf->p) {
    fprintf(stderr, "sshfs: memory allocation failed\n");
    abort();
  }
}

static inline void buf_check_add(struct buffer *buf, size_t len)
{
  if (buf->len + len > buf->size)
    buf_resize(buf, len);
}

#define _buf_add_mem(b, d, l)     \
  buf_check_add(b, l);      \
  memcpy(b->p + b->len, d, l);    \
  b->len += l;


static inline void buf_add_mem(struct buffer *buf, const void *data,
                               size_t len)
{
  _buf_add_mem(buf, data, len);
}

static inline void buf_add_buf(struct buffer *buf, const struct buffer *bufa)
{
  _buf_add_mem(buf, bufa->p, bufa->len);
}

static inline void buf_add_uint8(struct buffer *buf, uint8_t val)
{
  _buf_add_mem(buf, &val, 1);
}

static inline void buf_add_uint32(struct buffer *buf, uint32_t val)
{
  uint32_t nval = htonl(val);
  _buf_add_mem(buf, &nval, 4);
}

static inline void buf_add_uint64(struct buffer *buf, uint64_t val)
{
  buf_add_uint32(buf, val >> 32);
  buf_add_uint32(buf, val & 0xffffffff);
}

static inline void buf_add_data(struct buffer *buf, const struct buffer *data)
{
  buf_add_uint32(buf, data->len);
  buf_add_mem(buf, data->p, data->len);
}

static inline void buf_add_string(struct buffer *buf, const char *str)
{
  struct buffer data;
  data.p = (uint8_t *) str;
  data.len = strlen(str);
  buf_add_data(buf, &data);
}

static inline void buf_add_path(struct buffer *buf, const char *path)
{
  char *realpath;

  realpath = g_strdup_printf("%s%s", sshfs.base_path,
           path[1] ? path+1 : ".");
  buf_add_string(buf, realpath);
  g_free(realpath);
}

static int buf_check_get(struct buffer *buf, size_t len)
{
  if (buf->len + len > buf->size) {
    fprintf(stderr, "buffer too short\n");
    return -1;
  } else
    return 0;
}

static inline int buf_get_mem(struct buffer *buf, void *data, size_t len)
{
  if (buf_check_get(buf, len) == -1)
    return -1;
  memcpy(data, buf->p + buf->len, len);
  buf->len += len;
  return 0;
}

static inline int buf_get_uint8(struct buffer *buf, uint8_t *val)
{
  return buf_get_mem(buf, val, 1);
}

static inline int buf_get_uint32(struct buffer *buf, uint32_t *val)
{
  uint32_t nval;
  if (buf_get_mem(buf, &nval, 4) == -1)
    return -1;
  *val = ntohl(nval);
  return 0;
}

static inline int buf_get_uint64(struct buffer *buf, uint64_t *val)
{
  uint32_t val1;
  uint32_t val2;
  if (buf_get_uint32(buf, &val1) == -1 ||
      buf_get_uint32(buf, &val2) == -1) {
    return -1;
  }
  *val = ((uint64_t) val1 << 32) + val2;
  return 0;
}

static inline int buf_get_data(struct buffer *buf, struct buffer *data)
{
  uint32_t len;
  if (buf_get_uint32(buf, &len) == -1 || len > buf->size - buf->len)
    return -1;
  buf_init(data, len + 1);
  data->size = len;
  if (buf_get_mem(buf, data->p, data->size) == -1) {
    buf_free(data);
    return -1;
  }
  return 0;
}

static inline int buf_get_string(struct buffer *buf, char **str)
{
  struct buffer data;
  if (buf_get_data(buf, &data) == -1)
    return -1;
  data.p[data.size] = '\0';
  *str = (char *) data.p;
  return 0;
}

static int buf_get_attrs(struct buffer *buf, struct stat *stbuf, int *flagsp)
{
  uint32_t flags;
  uint64_t size = 0;
  uint32_t uid = 0;
  uint32_t gid = 0;
  uint32_t atime = 0;
  uint32_t mtime = 0;
  uint32_t mode = S_IFREG | 0777;

  if (buf_get_uint32(buf, &flags) == -1)
    return -1;
  if (flagsp)
    *flagsp = flags;
  if ((flags & SSH_FILEXFER_ATTR_SIZE) &&
      buf_get_uint64(buf, &size) == -1)
    return -1;
  if ((flags & SSH_FILEXFER_ATTR_UIDGID) &&
      (buf_get_uint32(buf, &uid) == -1 ||
       buf_get_uint32(buf, &gid) == -1))
    return -1;
  if ((flags & SSH_FILEXFER_ATTR_PERMISSIONS) &&
      buf_get_uint32(buf, &mode) == -1)
    return -1;
  if ((flags & SSH_FILEXFER_ATTR_ACMODTIME)) {
    if (buf_get_uint32(buf, &atime) == -1 ||
        buf_get_uint32(buf, &mtime) == -1)
      return -1;
  }
  if ((flags & SSH_FILEXFER_ATTR_EXTENDED)) {
    uint32_t extcount;
    unsigned i;
    if (buf_get_uint32(buf, &extcount) == -1)
      return -1;
    for (i = 0; i < extcount; i++) {
      struct buffer tmp;
      if (buf_get_data(buf, &tmp) == -1)
        return -1;
      buf_free(&tmp);
      if (buf_get_data(buf, &tmp) == -1)
        return -1;
      buf_free(&tmp);
    }
  }

  if (sshfs.remote_uid_detected && uid == sshfs.remote_uid)
    uid = sshfs.local_uid;

  memset(stbuf, 0, sizeof(struct stat));
  stbuf->st_mode = mode;
  stbuf->st_nlink = 1;
  stbuf->st_size = size;
  if (sshfs.blksize) {
    stbuf->st_blksize = sshfs.blksize;
    stbuf->st_blocks = ((size + sshfs.blksize - 1) &
            ~(sshfs.blksize - 1)) >> 9;
  }
  stbuf->st_uid = uid;
  stbuf->st_gid = gid;
  stbuf->st_atime = atime;
  stbuf->st_ctime = stbuf->st_mtime = mtime;
  return 0;
}

static int buf_get_entries(struct buffer *buf, fuse_cache_dirh_t h,
                           fuse_cache_dirfil_t filler)
{
  uint32_t count;
  unsigned i;

  if (buf_get_uint32(buf, &count) == -1)
    return -1;

  for (i = 0; i < count; i++) {
    int err = -1;
    char *name;
    char *longname;
    struct stat stbuf;
    if (buf_get_string(buf, &name) == -1)
      return -1;
    if (buf_get_string(buf, &longname) != -1) {
      free(longname);
      if (buf_get_attrs(buf, &stbuf, NULL) != -1) {
        if (sshfs.follow_symlinks &&
            S_ISLNK(stbuf.st_mode)) {
          stbuf.st_mode = 0;
        }
        filler(h, name, &stbuf);
        err = 0;
      }
    }
    free(name);
    if (err)
      return err;
  }
  return 0;
}

static void ssh_add_arg(const char *arg)
{
  if (fuse_opt_add_arg(&sshfs.ssh_args, arg) == -1)
    _exit(1);
}

#ifdef SSH_NODELAY_WORKAROUND
static int do_ssh_nodelay_workaround(void)
{
  char *oldpreload = getenv("LD_PRELOAD");
  char *newpreload;
  char sopath[PATH_MAX];
  int res;

  snprintf(sopath, sizeof(sopath), "%s/%s", LIBDIR, SSHNODELAY_SO);
  res = access(sopath, R_OK);
  if (res == -1) {
    char *s;
    if (!realpath(sshfs.progname, sopath))
      return -1;

    s = strrchr(sopath, '/');
    if (!s)
      s = sopath;
    else
      s++;

    if (s + strlen(SSHNODELAY_SO) >= sopath + sizeof(sopath))
      return -1;

    strcpy(s, SSHNODELAY_SO);
    res = access(sopath, R_OK);
    if (res == -1) {
      fprintf(stderr, "sshfs: cannot find %s\n",
        SSHNODELAY_SO);
      return -1;
    }
  }

  newpreload = g_strdup_printf("%s%s%s",
             oldpreload ? oldpreload : "",
             oldpreload ? " " : "",
             sopath);

  if (!newpreload || setenv("LD_PRELOAD", newpreload, 1) == -1) {
    fprintf(stderr, "warning: failed set LD_PRELOAD "
      "for ssh nodelay workaround\n");
  }
  g_free(newpreload);
  return 0;
}
#endif

static int start_ssh(void)
{
  int sockpair[2];
  int pid;

  if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair) == -1) {
    perror("failed to create socket pair");
    return -1;
  }
  sshfs.fd = sockpair[0];

  pid = fork();
  if (pid == -1) {
    perror("failed to fork");
    return -1;
  } else if (pid == 0) {
    int devnull;

#ifdef SSH_NODELAY_WORKAROUND
    if (sshfs.nodelay_workaround &&
        do_ssh_nodelay_workaround() == -1) {
      fprintf(stderr,
        "warning: ssh nodelay workaround disabled\n");
    }
#endif

    if (sshfs.nodelaysrv_workaround) {
      /*
       * Hack to work around missing TCP_NODELAY
       * setting in sshd
       */
      sshfs.ssh_args.argv[1] = "-X";
    }

    devnull = open("/dev/null", O_WRONLY);

    if (dup2(sockpair[1], 0) == -1 || dup2(sockpair[1], 1) == -1) {
      perror("failed to redirect input/output");
      _exit(1);
    }
    if (!sshfs.debug && devnull != -1)
      dup2(devnull, 2);

    close(devnull);
    close(sockpair[0]);
    close(sockpair[1]);

    switch (fork()) {
    case -1:
      perror("failed to fork");
      _exit(1);
    case 0:
      break;
    default:
      _exit(0);
    }
    chdir("/");

    execvp(sshfs.ssh_args.argv[0], sshfs.ssh_args.argv);
    perror("execvp");
    _exit(1);
  }
  waitpid(pid, NULL, 0);
  close(sockpair[1]);
  return 0;
}

static int connect_to(char *host, char *port)
{
  int err;
  int sock;
  int opt;
  struct addrinfo *ai;
  struct addrinfo hint;

  memset(&hint, 0, sizeof(hint));
  hint.ai_family = PF_INET;
  hint.ai_socktype = SOCK_STREAM;
  err = getaddrinfo(host, port, &hint, &ai);
  if (err) {
    fprintf(stderr, "failed to resolve %s:%s: %s\n", host, port,
      gai_strerror(err));
    return -1;
  }
  sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  if (sock == -1) {
    perror("failed to create socket");
    return -1;
  }
  err = connect(sock, ai->ai_addr, ai->ai_addrlen);
  if (err == -1) {
    perror("failed to connect");
    return -1;
  }
  opt = 1;
  err = setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
  if (err == -1)
    perror("warning: failed to set TCP_NODELAY");

  freeaddrinfo(ai);

  sshfs.fd = sock;
  return 0;
}

static int do_write(struct iovec *iov, size_t count)
{
  int res;
  while (count) {
    res = writev(sshfs.fd, iov, count);
    if (res == -1) {
      perror("write");
      return -1;
    } else if (res == 0) {
      fprintf(stderr, "zero write\n");
      return -1;
    }
    do {
      if ((unsigned) res < iov->iov_len) {
        iov->iov_len -= res;
        iov->iov_base += res;
        break;
      } else {
        res -= iov->iov_len;
        count --;
        iov ++;
      }
    } while(count);
  }
  return 0;
}

static uint32_t sftp_get_id(void)
{
  static uint32_t idctr;
  return idctr++;
}

static void buf_to_iov(const struct buffer *buf, struct iovec *iov)
{
  iov->iov_base = buf->p;
  iov->iov_len = buf->len;
}

static size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
{
  unsigned long seg;
  size_t ret = 0;

  for (seg = 0; seg < nr_segs; seg++)
    ret += iov[seg].iov_len;
  return ret;
}

#define SFTP_MAX_IOV 3

static int sftp_send_iov(uint8_t type, uint32_t id, struct iovec iov[],
                         size_t count)
{
  int res;
  struct buffer buf;
  struct iovec iovout[SFTP_MAX_IOV];
  unsigned i;
  unsigned nout = 0;

  assert(count <= SFTP_MAX_IOV - 1);
  buf_init(&buf, 9);
  buf_add_uint32(&buf, iov_length(iov, count) + 5);
  buf_add_uint8(&buf, type);
  buf_add_uint32(&buf, id);
  buf_to_iov(&buf, &iovout[nout++]);
  for (i = 0; i < count; i++)
    iovout[nout++] = iov[i];
  pthread_mutex_lock(&sshfs.lock_write);
  res = do_write(iovout, nout);
  pthread_mutex_unlock(&sshfs.lock_write);
  buf_free(&buf);
  return res;
}

static int do_read(struct buffer *buf)
{
  int res;
  uint8_t *p = buf->p;
  size_t size = buf->size;
  while (size) {
    res = read(sshfs.fd, p, size);
    if (res == -1) {
      perror("read");
      return -1;
    } else if (res == 0) {
      fprintf(stderr, "remote host has disconnected\n");
      return -1;
    }
    size -= res;
    p += res;
  }
  return 0;
}

static int sftp_read(uint8_t *type, struct buffer *buf)
{
  int res;
  struct buffer buf2;
  uint32_t len;
  buf_init(&buf2, 5);
  res = do_read(&buf2);
  if (res != -1) {
    if (buf_get_uint32(&buf2, &len) == -1)
      return -1;
    if (len > MAX_REPLY_LEN) {
      fprintf(stderr, "reply len too large: %u\n", len);
      return -1;
    }
    if (buf_get_uint8(&buf2, type) == -1)
      return -1;
    buf_init(buf, len - 1);
    res = do_read(buf);
  }
  buf_free(&buf2);
  return res;
}

static void request_free(struct request *req)
{
  buf_free(&req->reply);
  sem_destroy(&req->ready);
  g_free(req);
}

static void chunk_free(struct read_chunk *chunk)
{
  buf_free(&chunk->data);
  sem_destroy(&chunk->ready);
  g_free(chunk);
}

static void chunk_put(struct read_chunk *chunk)
{
  if (chunk) {
    chunk->refs--;
    if (!chunk->refs)
      chunk_free(chunk);
  }
}

static void chunk_put_locked(struct read_chunk *chunk)
{
  pthread_mutex_lock(&sshfs.lock);
  chunk_put(chunk);
  pthread_mutex_unlock(&sshfs.lock);
}

static int clean_req(void *key_, struct request *req)
{
  (void) key_;

  req->error = -EIO;
  if (req->want_reply)
    sem_post(&req->ready);
  else {
    if (req->end_func)
      req->end_func(req);
    request_free(req);
  }
  return TRUE;
}

static int process_one_request(void)
{
  int res;
  struct buffer buf;
  uint8_t type;
  struct request *req;
  uint32_t id;

  buf_init(&buf, 0);
  res = sftp_read(&type, &buf);
  if (res == -1)
    return -1;
  if (buf_get_uint32(&buf, &id) == -1)
    return -1;

  pthread_mutex_lock(&sshfs.lock);
  req = (struct request *)
    g_hash_table_lookup(sshfs.reqtab, GUINT_TO_POINTER(id));
  if (req == NULL)
    fprintf(stderr, "request %i not found\n", id);
  else {
    int was_over;

    was_over = sshfs.outstanding_len > sshfs.max_outstanding_len;
    sshfs.outstanding_len -= req->len;
    if (was_over &&
        sshfs.outstanding_len <= sshfs.max_outstanding_len) {
      pthread_cond_broadcast(&sshfs.outstanding_cond);
    }
    g_hash_table_remove(sshfs.reqtab, GUINT_TO_POINTER(id));
  }
  pthread_mutex_unlock(&sshfs.lock);
  if (req != NULL) {
    if (sshfs.debug) {
      struct timeval now;
      unsigned int difftime;
      gettimeofday(&now, NULL);
      difftime = (now.tv_sec - req->start.tv_sec) * 1000;
      difftime += (now.tv_usec - req->start.tv_usec) / 1000;
      DEBUG("  [%05i] %14s %8ubytes (%ims)\n", id,
            type_name(type),
            (unsigned) buf.size + 5, difftime);
    }
    req->reply = buf;
    req->reply_type = type;
    req->replied = 1;
    if (req->want_reply)
      sem_post(&req->ready);
    else {
      if (req->end_func) {
        pthread_mutex_lock(&sshfs.lock);
        req->end_func(req);
        pthread_mutex_unlock(&sshfs.lock);
      }
      request_free(req);
    }
  } else
    buf_free(&buf);

  return 0;
}

static void *process_requests(void *data_)
{
  (void) data_;

  while (1) {
    if (process_one_request() == -1)
      break;
  }

  if (!sshfs.reconnect) {
    /* harakiri */
    kill(getpid(), SIGTERM);
  } else {
    pthread_mutex_lock(&sshfs.lock);
    sshfs.processing_thread_started = 0;
    close(sshfs.fd);
    sshfs.fd = -1;
    g_hash_table_foreach_remove(sshfs.reqtab, (GHRFunc) clean_req,
              NULL);
    sshfs.connver ++;
    pthread_mutex_unlock(&sshfs.lock);
  }
  return NULL;
}

static int sftp_init_reply_ok(struct buffer *buf, uint32_t *version)
{
  uint32_t len;
  uint8_t type;

  if (buf_get_uint32(buf, &len) == -1)
    return -1;

  if (len < 5 || len > MAX_REPLY_LEN)
    return 1;

  if (buf_get_uint8(buf, &type) == -1)
    return -1;

  if (type != SSH_FXP_VERSION)
    return 1;

  if (buf_get_uint32(buf, version) == -1)
    return -1;

  if (len > 5) {
    struct buffer buf2;
    buf_init(&buf2, len - 5);
    return do_read(&buf2);
  }
  return 0;
}

static int sftp_find_init_reply(uint32_t *version)
{
  int res;
  struct buffer buf;

  buf_init(&buf, 9);
  res = do_read(&buf);
  while (res != -1) {
    struct buffer buf2;

    res = sftp_init_reply_ok(&buf, version);
    if (res <= 0)
      break;

    /* Iterate over any rubbish until the version reply is found */
    DEBUG("%c", *buf.p);
    memmove(buf.p, buf.p + 1, buf.size - 1);
    buf.len = 0;
    buf2.p = buf.p + buf.size - 1;
    buf2.size = 1;
    res = do_read(&buf2);
  }
  buf_free(&buf);
  return res;
}

static int sftp_init()
{
  int res = -1;
  uint32_t version = 0;
  struct buffer buf;
  buf_init(&buf, 0);
  if (sftp_send_iov(SSH_FXP_INIT, PROTO_VERSION, NULL, 0) == -1)
    goto out;
  if (sftp_find_init_reply(&version) == -1)
    goto out;

  sshfs.server_version = version;
  DEBUG("Server version: %i\n", sshfs.server_version);
  if (version > PROTO_VERSION) {
    fprintf(stderr,
      "Warning: server uses version: %i, we support: %i\n",
      version, PROTO_VERSION);
  }
  res = 0;

out:
  buf_free(&buf);
  return res;
}

static int sftp_error_to_errno(uint32_t error)
{
  switch (error) {
  case SSH_FX_OK:                return 0;
  case SSH_FX_NO_SUCH_FILE:      return ENOENT;
  case SSH_FX_PERMISSION_DENIED: return EACCES;
  case SSH_FX_FAILURE:           return EPERM;
  case SSH_FX_BAD_MESSAGE:       return EBADMSG;
  case SSH_FX_NO_CONNECTION:     return ENOTCONN;
  case SSH_FX_CONNECTION_LOST:   return ECONNABORTED;
  case SSH_FX_OP_UNSUPPORTED:    return EOPNOTSUPP;
  default:                       return EIO;
  }
}

static void sftp_detect_uid()
{
  int flags;
  uint32_t id = sftp_get_id();
  uint32_t replid;
  uint8_t type;
  struct buffer buf;
  struct stat stbuf;
  struct iovec iov[1];

  buf_init(&buf, 5);
  buf_add_string(&buf, ".");
  buf_to_iov(&buf, &iov[0]);
  if (sftp_send_iov(SSH_FXP_STAT, id, iov, 1) == -1)
    goto out;
  buf_clear(&buf);
  if (sftp_read(&type, &buf) == -1)
    goto out;
  if (type != SSH_FXP_ATTRS && type != SSH_FXP_STATUS) {
    fprintf(stderr, "protocol error\n");
    goto out;
  }
  if (buf_get_uint32(&buf, &replid) == -1)
    goto out;
  if (replid != id) {
    fprintf(stderr, "bad reply ID\n");
    goto out;
  }
  if (type == SSH_FXP_STATUS) {
    uint32_t serr;
    if (buf_get_uint32(&buf, &serr) == -1)
      goto out;

    fprintf(stderr, "failed to stat home directory (%i)\n", serr);
    goto out;
  }
  if (buf_get_attrs(&buf, &stbuf, &flags) == -1)
    goto out;

  if (!(flags & SSH_FILEXFER_ATTR_UIDGID))
    goto out;

  sshfs.remote_uid = stbuf.st_uid;
  sshfs.local_uid = getuid();
  sshfs.remote_uid_detected = 1;
  DEBUG("remote_uid = %i\n", sshfs.remote_uid);

out:
  if (!sshfs.remote_uid_detected)
    fprintf(stderr, "failed to detect remote user ID\n");

  buf_free(&buf);
}

static int sftp_check_root(const char *base_path)
{
  int flags;
  uint32_t id = sftp_get_id();
  uint32_t replid;
  uint8_t type;
  struct buffer buf;
  struct stat stbuf;
  struct iovec iov[1];
  int err = -1;
  const char *remote_dir = base_path[0] ? base_path : ".";

  buf_init(&buf, 0);
  buf_add_string(&buf, remote_dir);
  buf_to_iov(&buf, &iov[0]);
  if (sftp_send_iov(SSH_FXP_STAT, id, iov, 1) == -1)
    goto out;
  buf_clear(&buf);
  if (sftp_read(&type, &buf) == -1)
    goto out;
  if (type != SSH_FXP_ATTRS && type != SSH_FXP_STATUS) {
    fprintf(stderr, "protocol error\n");
    goto out;
  }
  if (buf_get_uint32(&buf, &replid) == -1)
    goto out;
  if (replid != id) {
    fprintf(stderr, "bad reply ID\n");
    goto out;
  }
  if (type == SSH_FXP_STATUS) {
    uint32_t serr;
    if (buf_get_uint32(&buf, &serr) == -1)
      goto out;

    fprintf(stderr, "%s:%s: %s\n", sshfs.host, remote_dir,
      strerror(sftp_error_to_errno(serr)));

    goto out;
  }
  if (buf_get_attrs(&buf, &stbuf, &flags) == -1)
    goto out;

  if (!(flags & SSH_FILEXFER_ATTR_PERMISSIONS))
    goto out;

  if (!S_ISDIR(stbuf.st_mode)) {
    fprintf(stderr, "%s:%s: Not a directory\n", sshfs.host,
      remote_dir);
    goto out;
  }

  err = 0;

out:
  buf_free(&buf);
  return err;
}

static int connect_remote(void)
{
  int err;

  if (sshfs.directport)
    err = connect_to(sshfs.host, sshfs.directport);
  else
    err = start_ssh();
  if (!err)
    err = sftp_init();

  return err;
}

static int start_processing_thread(void)
{
  int err;
  pthread_t thread_id;
  sigset_t oldset;
  sigset_t newset;

  if (sshfs.processing_thread_started)
    return 0;

  if (sshfs.fd == -1) {
    err = connect_remote();
    if (err)
      return -EIO;
  }

  sigemptyset(&newset);
  sigaddset(&newset, SIGTERM);
  sigaddset(&newset, SIGINT);
  sigaddset(&newset, SIGHUP);
  sigaddset(&newset, SIGQUIT);
  pthread_sigmask(SIG_BLOCK, &newset, &oldset);
  err = pthread_create(&thread_id, NULL, process_requests, NULL);
  if (err) {
    fprintf(stderr, "failed to create thread: %s\n", strerror(err));
    return -EIO;
  }
  pthread_detach(thread_id);
  pthread_sigmask(SIG_SETMASK, &oldset, NULL);
  sshfs.processing_thread_started = 1;
  return 0;
}

#ifdef SSHFS_USE_INIT
#if FUSE_VERSION >= 26
static void *sshfs_init(struct fuse_conn_info *conn)
#else
  static void *sshfs_init(void)
#endif
{
#if FUSE_VERSION >= 26
  /* Readahead should be done by kernel or sshfs but not both */
  if (conn->async_read)
    sshfs.sync_read = 1;
#endif

  if (sshfs.detect_uid)
    sftp_detect_uid();

  start_processing_thread();
  return NULL;
}
#endif

static int sftp_request_wait(struct request *req, uint8_t type,
                             uint8_t expect_type, struct buffer *outbuf)
{
  int err;

  if (req->error) {
    err = req->error;
    goto out;
  }
  while (sem_wait(&req->ready));
  if (req->error) {
    err = req->error;
    goto out;
  }
  err = -EIO;
  if (req->reply_type != expect_type &&
      req->reply_type != SSH_FXP_STATUS) {
    fprintf(stderr, "protocol error\n");
    goto out;
  }
  if (req->reply_type == SSH_FXP_STATUS) {
    uint32_t serr;
    if (buf_get_uint32(&req->reply, &serr) == -1)
      goto out;

    switch (serr) {
    case SSH_FX_OK:
      if (expect_type == SSH_FXP_STATUS)
        err = 0;
      else
        err = -EIO;
      break;

    case SSH_FX_EOF:
      if (type == SSH_FXP_READ || type == SSH_FXP_READDIR)
        err = MY_EOF;
      else
        err = -EIO;
      break;

    default:
      err = -sftp_error_to_errno(serr);
    }
  } else {
    buf_init(outbuf, req->reply.size - req->reply.len);
    buf_get_mem(&req->reply, outbuf->p, outbuf->size);
    err = 0;
  }

out:
  if (req->end_func) {
    pthread_mutex_lock(&sshfs.lock);
    req->end_func(req);
    pthread_mutex_unlock(&sshfs.lock);
  }
  request_free(req);
  return err;
}

static int sftp_request_send(uint8_t type, struct iovec *iov, size_t count,
                             request_func begin_func, request_func end_func,
                             int want_reply, void *data,
                             struct request **reqp)
{
  int err;
  uint32_t id;
  struct request *req = g_new0(struct request, 1);

  req->want_reply = want_reply;
  req->end_func = end_func;
  req->data = data;
  sem_init(&req->ready, 0, 0);
  buf_init(&req->reply, 0);
  pthread_mutex_lock(&sshfs.lock);
  if (begin_func)
    begin_func(req);
  id = sftp_get_id();
  err = start_processing_thread();
  if (err) {
    pthread_mutex_unlock(&sshfs.lock);
    goto out;
  }
  req->len = iov_length(iov, count) + 9;
  sshfs.outstanding_len += req->len;
  while (sshfs.outstanding_len > sshfs.max_outstanding_len)
    pthread_cond_wait(&sshfs.outstanding_cond, &sshfs.lock);

  g_hash_table_insert(sshfs.reqtab, GUINT_TO_POINTER(id), req);
  if (sshfs.debug)
    gettimeofday(&req->start, NULL);
  DEBUG("[%05i] %s\n", id, type_name(type));
  pthread_mutex_unlock(&sshfs.lock);

  err = -EIO;
  if (sftp_send_iov(type, id, iov, count) == -1) {
    pthread_mutex_lock(&sshfs.lock);
    g_hash_table_remove(sshfs.reqtab, GUINT_TO_POINTER(id));
    pthread_mutex_unlock(&sshfs.lock);
    goto out;
  }
  if (want_reply)
    *reqp = req;
  return 0;

out:
  req->error = err;
  if (!want_reply)
    sftp_request_wait(req, type, 0, NULL);
  else
    *reqp = req;

  return err;
}


static int sftp_request_iov(uint8_t type, struct iovec *iov, size_t count,
                            uint8_t expect_type, struct buffer *outbuf)
{
  struct request *req;

  sftp_request_send(type, iov, count, NULL, NULL, expect_type, NULL,
        &req);
  if (expect_type == 0)
    return 0;

  return sftp_request_wait(req, type, expect_type, outbuf);
}

static int sftp_request(uint8_t type, const struct buffer *buf,
                        uint8_t expect_type, struct buffer *outbuf)
{
  struct iovec iov;

  buf_to_iov(buf, &iov);
  return sftp_request_iov(type, &iov, 1, expect_type, outbuf);
}

static int sshfs_getattr(const char *path, struct stat *stbuf)
{
  int err;
  struct buffer buf;
  struct buffer outbuf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  err = sftp_request(sshfs.follow_symlinks ? SSH_FXP_STAT : SSH_FXP_LSTAT,
         &buf, SSH_FXP_ATTRS, &outbuf);
  if (!err) {
    if (buf_get_attrs(&outbuf, stbuf, NULL) == -1)
      err = -EIO;
    buf_free(&outbuf);
  }
  buf_free(&buf);
  return err;
}

static int count_components(const char *p)
{
  int ctr;

  for (; *p == '/'; p++);
  for (ctr = 0; *p; ctr++) {
    for (; *p && *p != '/'; p++);
    for (; *p == '/'; p++);
  }
  return ctr;
}

static void strip_common(const char **sp, const char **tp)
{
  const char *s = *sp;
  const char *t = *tp;
  do {
    for (; *s == '/'; s++);
    for (; *t == '/'; t++);
    *tp = t;
    *sp = s;
    for (; *s == *t && *s && *s != '/'; s++, t++);
  } while ((*s == *t && *s) || (!*s && *t == '/') || (*s == '/' && !*t));
}

static void transform_symlink(const char *path, char **linkp)
{
  const char *l = *linkp;
  const char *b = sshfs.base_path;
  char *newlink;
  char *s;
  int dotdots;
  int i;

  if (l[0] != '/' || b[0] != '/')
    return;

  strip_common(&l, &b);
  if (*b)
    return;

  strip_common(&l, &path);
  dotdots = count_components(path);
  if (!dotdots)
    return;
  dotdots--;

  newlink = malloc(dotdots * 3 + strlen(l) + 2);
  if (!newlink) {
    fprintf(stderr, "sshfs: memory allocation failed\n");
    abort();
  }
  for (s = newlink, i = 0; i < dotdots; i++, s += 3)
    strcpy(s, "../");

  if (l[0])
    strcpy(s, l);
  else if (!dotdots)
    strcpy(s, ".");
  else
    s[0] = '\0';

  free(*linkp);
  *linkp = newlink;
}

static int sshfs_readlink(const char *path, char *linkbuf, size_t size)
{
  int err;
  struct buffer buf;
  struct buffer name;

  assert(size > 0);

  if (sshfs.server_version < 3)
    return -EPERM;

  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  err = sftp_request(SSH_FXP_READLINK, &buf, SSH_FXP_NAME, &name);
  if (!err) {
    uint32_t count;
    char *link;
    err = -EIO;
    if(buf_get_uint32(&name, &count) != -1 && count == 1 &&
       buf_get_string(&name, &link) != -1) {
      if (sshfs.transform_symlinks)
        transform_symlink(path, &link);
      strncpy(linkbuf, link, size - 1);
      linkbuf[size - 1] = '\0';
      free(link);
      err = 0;
    }
    buf_free(&name);
  }
  buf_free(&buf);
  return err;
}

static int sshfs_getdir(const char *path, fuse_cache_dirh_t h,
                        fuse_cache_dirfil_t filler)
{
  int err;
  struct buffer buf;
  struct buffer handle;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  err = sftp_request(SSH_FXP_OPENDIR, &buf, SSH_FXP_HANDLE, &handle);
  if (!err) {
    int err2;
    buf_finish(&handle);
    do {
      struct buffer name;
      err = sftp_request(SSH_FXP_READDIR, &handle, SSH_FXP_NAME, &name);
      if (!err) {
        if (buf_get_entries(&name, h, filler) == -1)
          err = -EIO;
        buf_free(&name);
      }
    } while (!err);
    if (err == MY_EOF)
      err = 0;

    err2 = sftp_request(SSH_FXP_CLOSE, &handle, 0, NULL);
    if (!err)
      err = err2;
    buf_free(&handle);
  }
  buf_free(&buf);
  return err;
}

static int sshfs_mkdir(const char *path, mode_t mode)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
  buf_add_uint32(&buf, mode);
  err = sftp_request(SSH_FXP_MKDIR, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_mknod(const char *path, mode_t mode, dev_t rdev)
{
  int err;
  struct buffer buf;
  struct buffer handle;
  (void) rdev;

  if ((mode & S_IFMT) != S_IFREG)
    return -EPERM;

  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FXF_WRITE | SSH_FXF_CREAT | SSH_FXF_EXCL);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
  buf_add_uint32(&buf, mode);
  err = sftp_request(SSH_FXP_OPEN, &buf, SSH_FXP_HANDLE, &handle);
  if (!err) {
    int err2;
    buf_finish(&handle);
    err2 = sftp_request(SSH_FXP_CLOSE, &handle, SSH_FXP_STATUS,
            NULL);
    if (!err)
      err = err2;
    buf_free(&handle);
  }
  buf_free(&buf);
  return err;
}

static int sshfs_symlink(const char *from, const char *to)
{
  int err;
  struct buffer buf;

  if (sshfs.server_version < 3)
    return -EPERM;

  /* openssh sftp server doesn't follow standard: link target and
     link name are mixed up, so we must also be non-standard :( */
  buf_init(&buf, 0);
  buf_add_string(&buf, from);
  buf_add_path(&buf, to);
  err = sftp_request(SSH_FXP_SYMLINK, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_unlink(const char *path)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  err = sftp_request(SSH_FXP_REMOVE, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_rmdir(const char *path)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  err = sftp_request(SSH_FXP_RMDIR, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_do_rename(const char *from, const char *to)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, from);
  buf_add_path(&buf, to);
  err = sftp_request(SSH_FXP_RENAME, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static void random_string(char *str, int length)
{
  int i;
  for (i = 0; i < length; i++)
    *str++ = (char)('0' + rand_r(&sshfs.randseed) % 10);
  *str = '\0';
}

static int sshfs_rename(const char *from, const char *to)
{
  int err;
  err = sshfs_do_rename(from, to);
  if (err == -EPERM && sshfs.rename_workaround) {
    size_t tolen = strlen(to);
    if (tolen + RENAME_TEMP_CHARS < PATH_MAX) {
      int tmperr;
      char totmp[PATH_MAX];
      strcpy(totmp, to);
      random_string(totmp + tolen, RENAME_TEMP_CHARS);
      tmperr = sshfs_do_rename(to, totmp);
      if (!tmperr) {
        err = sshfs_do_rename(from, to);
        if (!err)
          err = sshfs_unlink(totmp);
        else
          sshfs_do_rename(totmp, to);
      }
    }
  }
  return err;
}

static int sshfs_chmod(const char *path, mode_t mode)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
  buf_add_uint32(&buf, mode);
  err = sftp_request(SSH_FXP_SETSTAT, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_chown(const char *path, uid_t uid, gid_t gid)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_UIDGID);
  buf_add_uint32(&buf, uid);
  buf_add_uint32(&buf, gid);
  err = sftp_request(SSH_FXP_SETSTAT, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_truncate_workaround(const char *path, off_t size,
                                     struct fuse_file_info *fi);

static int sshfs_truncate(const char *path, off_t size)
{
  int err;
  struct buffer buf;

  sshfs.modifver ++;
  if (size == 0 || sshfs.truncate_workaround)
    return sshfs_truncate_workaround(path, size, NULL);

  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_SIZE);
  buf_add_uint64(&buf, size);
  err = sftp_request(SSH_FXP_SETSTAT, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static int sshfs_utime(const char *path, struct utimbuf *ubuf)
{
  int err;
  struct buffer buf;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_ACMODTIME);
  buf_add_uint32(&buf, ubuf->actime);
  buf_add_uint32(&buf, ubuf->modtime);
  err = sftp_request(SSH_FXP_SETSTAT, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);
  return err;
}

static inline int sshfs_file_is_conn(struct sshfs_file *sf)
{
  return sf->connver == sshfs.connver;
}

static int sshfs_open_common(const char *path, mode_t mode,
                             struct fuse_file_info *fi)
{
  int err;
  int err2;
  struct buffer buf;
  struct buffer outbuf;
  struct stat stbuf;
  struct sshfs_file *sf;
  struct request *open_req;
  uint32_t pflags = 0;
  struct iovec iov;
  uint8_t type;

  if ((fi->flags & O_ACCMODE) == O_RDONLY)
    pflags = SSH_FXF_READ;
  else if((fi->flags & O_ACCMODE) == O_WRONLY)
    pflags = SSH_FXF_WRITE;
  else if ((fi->flags & O_ACCMODE) == O_RDWR)
    pflags = SSH_FXF_READ | SSH_FXF_WRITE;
  else
    return -EINVAL;

  if (fi->flags & O_CREAT)
    pflags |= SSH_FXF_CREAT;

  if (fi->flags & O_EXCL)
    pflags |= SSH_FXF_EXCL;

  if (fi->flags & O_TRUNC)
    pflags |= SSH_FXF_TRUNC;

  sf = g_new0(struct sshfs_file, 1);
  list_init(&sf->write_reqs);
  pthread_cond_init(&sf->write_finished, NULL);
  /* Assume random read after open */
  sf->is_seq = 0;
  sf->refs = 1;
  sf->next_pos = 0;
  sf->modifver= sshfs.modifver;
  sf->connver = sshfs.connver;
  buf_init(&buf, 0);
  buf_add_path(&buf, path);
  buf_add_uint32(&buf, pflags);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
  buf_add_uint32(&buf, mode);
  buf_to_iov(&buf, &iov);
  sftp_request_send(SSH_FXP_OPEN, &iov, 1, NULL, NULL, 1, NULL,
        &open_req);
  buf_clear(&buf);
  buf_add_path(&buf, path);
  type = sshfs.follow_symlinks ? SSH_FXP_STAT : SSH_FXP_LSTAT;
  err2 = sftp_request(type, &buf, SSH_FXP_ATTRS, &outbuf);
  if (!err2) {
    if (buf_get_attrs(&outbuf, &stbuf, NULL) == -1)
      err2 = -EIO;
    buf_free(&outbuf);
  }
  err = sftp_request_wait(open_req, SSH_FXP_OPEN, SSH_FXP_HANDLE,
        &sf->handle);
  if (!err && err2) {
    buf_finish(&sf->handle);
    sftp_request(SSH_FXP_CLOSE, &sf->handle, 0, NULL);
    buf_free(&sf->handle);
    err = err2;
  }

  if (!err) {
    cache_add_attr(path, &stbuf);
    buf_finish(&sf->handle);
    fi->fh = (unsigned long) sf;
  } else {
    cache_invalidate(path);
    g_free(sf);
  }
  buf_free(&buf);
  return err;
}

static int sshfs_open(const char *path, struct fuse_file_info *fi)
{
  return sshfs_open_common(path, 0, fi);
}

static inline struct sshfs_file *get_sshfs_file(struct fuse_file_info *fi)
{
  return (struct sshfs_file *) (uintptr_t) fi->fh;
}

static int sshfs_flush(const char *path, struct fuse_file_info *fi)
{
  int err;
  struct sshfs_file *sf = get_sshfs_file(fi);
  struct list_head write_reqs;
  struct list_head *curr_list;

  if (!sshfs_file_is_conn(sf))
    return -EIO;

  if (sshfs.sync_write)
    return 0;

  (void) path;
  pthread_mutex_lock(&sshfs.lock);
  if (!list_empty(&sf->write_reqs)) {
    curr_list = sf->write_reqs.prev;
    list_del(&sf->write_reqs);
    list_init(&sf->write_reqs);
    list_add(&write_reqs, curr_list);
    while (!list_empty(&write_reqs))
      pthread_cond_wait(&sf->write_finished, &sshfs.lock);
  }
  err = sf->write_error;
  sf->write_error = 0;
  pthread_mutex_unlock(&sshfs.lock);
  return err;
}

static int sshfs_fsync(const char *path, int isdatasync,
                       struct fuse_file_info *fi)
{
  (void) isdatasync;
  return sshfs_flush(path, fi);
}

static void sshfs_file_put(struct sshfs_file *sf)
{
  sf->refs--;
  if (!sf->refs)
    g_free(sf);
}

static void sshfs_file_get(struct sshfs_file *sf)
{
  sf->refs++;
}

static int sshfs_release(const char *path, struct fuse_file_info *fi)
{
  struct sshfs_file *sf = get_sshfs_file(fi);
  struct buffer *handle = &sf->handle;
  if (sshfs_file_is_conn(sf)) {
    sshfs_flush(path, fi);
    sftp_request(SSH_FXP_CLOSE, handle, 0, NULL);
  }
  buf_free(handle);
  chunk_put_locked(sf->readahead);
  sshfs_file_put(sf);
  return 0;
}

static int sshfs_sync_read(struct sshfs_file *sf, char *rbuf, size_t size,
                           off_t offset)
{
  int err;
  struct buffer buf;
  struct buffer data;
  struct buffer *handle = &sf->handle;
  buf_init(&buf, 0);
  buf_add_buf(&buf, handle);
  buf_add_uint64(&buf, offset);
  buf_add_uint32(&buf, size);
  err = sftp_request(SSH_FXP_READ, &buf, SSH_FXP_DATA, &data);
  if (!err) {
    uint32_t retsize;
    err = -EIO;
    if (buf_get_uint32(&data, &retsize) != -1) {
      if (retsize > size)
        fprintf(stderr, "long read\n");
      else {
        buf_get_mem(&data, rbuf, retsize);
        err = retsize;
      }
    }
    buf_free(&data);
  } else if (err == MY_EOF)
    err = 0;
  buf_free(&buf);
  return err;
}

static void sshfs_read_end(struct request *req)
{
  struct read_chunk *chunk = (struct read_chunk *) req->data;
  if (req->error)
    chunk->res = req->error;
  else if (req->replied) {
    chunk->res = -EIO;

    if (req->reply_type == SSH_FXP_STATUS) {
      uint32_t serr;
      if (buf_get_uint32(&req->reply, &serr) != -1) {
        if (serr == SSH_FX_EOF)
          chunk->res = 0;
      }
    } else if (req->reply_type == SSH_FXP_DATA) {
      uint32_t retsize;
      if (buf_get_uint32(&req->reply, &retsize) != -1) {
        if (retsize > chunk->size)
          fprintf(stderr, "long read\n");
        else {
          chunk->res = retsize;
          chunk->data = req->reply;
          buf_init(&req->reply, 0);
        }
      }
    } else
      fprintf(stderr, "protocol error\n");
  } else
    chunk->res = -EIO;

  sem_post(&chunk->ready);
  chunk_put(chunk);
}

static void sshfs_read_begin(struct request *req)
{
  struct read_chunk *chunk = (struct read_chunk *) req->data;
  chunk->refs++;
}

static void sshfs_send_async_read(struct sshfs_file *sf,
                                  struct read_chunk *chunk)
{
  struct buffer buf;
  struct buffer *handle = &sf->handle;
  struct iovec iov;

  buf_init(&buf, 0);
  buf_add_buf(&buf, handle);
  buf_add_uint64(&buf, chunk->offset);
  buf_add_uint32(&buf, chunk->size);
  buf_to_iov(&buf, &iov);
  sftp_request_send(SSH_FXP_READ, &iov, 1, sshfs_read_begin,
        sshfs_read_end, 0, chunk, NULL);
  buf_free(&buf);
}

static void submit_read(struct sshfs_file *sf, size_t size, off_t offset,
                        struct read_chunk **chunkp)
{
  struct read_chunk *chunk = g_new0(struct read_chunk, 1);

  sem_init(&chunk->ready, 0, 0);
  buf_init(&chunk->data, 0);
  chunk->offset = offset;
  chunk->size = size;
  chunk->refs = 1;
  chunk->modifver = sshfs.modifver;
  sshfs_send_async_read(sf, chunk);
  pthread_mutex_lock(&sshfs.lock);
  chunk_put(*chunkp);
  *chunkp = chunk;
  pthread_mutex_unlock(&sshfs.lock);
}

static int wait_chunk(struct read_chunk *chunk, char *buf, size_t size)
{
  int res;
  while (sem_wait(&chunk->ready));
  res = chunk->res;
  if (res > 0) {
    if ((size_t) res > size)
      res = size;
    buf_get_mem(&chunk->data, buf, res);
    chunk->offset += res;
    chunk->size -= res;
    chunk->res -= res;
  }
  sem_post(&chunk->ready);
  chunk_put_locked(chunk);
  return res;
}

static struct read_chunk *search_read_chunk(struct sshfs_file *sf, off_t offset)
{
  struct read_chunk *ch = sf->readahead;
  if (ch && ch->offset == offset && ch->modifver == sshfs.modifver) {
    ch->refs++;
    return ch;
  } else
    return NULL;
}

static int sshfs_async_read(struct sshfs_file *sf, char *rbuf, size_t size,
                            off_t offset)
{
  int res = 0;
  size_t total = 0;
  struct read_chunk *chunk;
  struct read_chunk *chunk_prev = NULL;
  size_t origsize = size;
  int curr_is_seq;

  pthread_mutex_lock(&sshfs.lock);
  curr_is_seq = sf->is_seq;
  sf->is_seq = (sf->next_pos == offset && sf->modifver == sshfs.modifver);
  sf->next_pos = offset + size;
  sf->modifver = sshfs.modifver;
  chunk = search_read_chunk(sf, offset);
  pthread_mutex_unlock(&sshfs.lock);

  if (chunk && chunk->size < size) {
    chunk_prev = chunk;
    size -= chunk->size;
    offset += chunk->size;
    chunk = NULL;
  }

  if (!chunk)
    submit_read(sf, size, offset, &chunk);

  if (curr_is_seq && chunk && chunk->size <= size)
    submit_read(sf, origsize, offset + size, &sf->readahead);

  if (chunk_prev) {
    size_t prev_size = chunk_prev->size;
    res = wait_chunk(chunk_prev, rbuf, prev_size);
    if (res < (int) prev_size) {
      chunk_put_locked(chunk);
      return res;
    }
    rbuf += res;
    total += res;
  }
  res = wait_chunk(chunk, rbuf, size);
  if (res > 0)
    total += res;
  if (res < 0)
    return res;

  return total;
}

static int sshfs_read(const char *path, char *rbuf, size_t size, off_t offset,
                      struct fuse_file_info *fi)
{
  struct sshfs_file *sf = get_sshfs_file(fi);
  (void) path;

  if (!sshfs_file_is_conn(sf))
    return -EIO;

  if (sshfs.sync_read)
    return sshfs_sync_read(sf, rbuf, size, offset);
  else
    return sshfs_async_read(sf, rbuf, size, offset);
}

static void sshfs_write_begin(struct request *req)
{
  struct sshfs_file *sf = (struct sshfs_file *) req->data;

  sshfs_file_get(sf);
  list_add(&req->list, &sf->write_reqs);
}

static void sshfs_write_end(struct request *req)
{
  uint32_t serr;
  struct sshfs_file *sf = (struct sshfs_file *) req->data;

  if (req->error)
    sf->write_error = req->error;
  else if (req->replied) {
    if (req->reply_type != SSH_FXP_STATUS) {
      fprintf(stderr, "protocol error\n");
    } else if (buf_get_uint32(&req->reply, &serr) != -1 &&
       serr != SSH_FX_OK) {
      sf->write_error = -EIO;
    }
  }
  list_del(&req->list);
  pthread_cond_broadcast(&sf->write_finished);
  sshfs_file_put(sf);
}

static int sshfs_write(const char *path, const char *wbuf, size_t size,
                       off_t offset, struct fuse_file_info *fi)
{
  int err;
  struct buffer buf;
  struct sshfs_file *sf = get_sshfs_file(fi);
  struct buffer *handle = &sf->handle;
  struct iovec iov[2];

  (void) path;

  if (!sshfs_file_is_conn(sf))
    return -EIO;

  sshfs.modifver ++;
  buf_init(&buf, 0);
  buf_add_buf(&buf, handle);
  buf_add_uint64(&buf, offset);
  buf_add_uint32(&buf, size);
  buf_to_iov(&buf, &iov[0]);
  iov[1].iov_base = (void *) wbuf;
  iov[1].iov_len = size;
  if (!sshfs.sync_write && !sf->write_error) {
    err = sftp_request_send(SSH_FXP_WRITE, iov, 2,
          sshfs_write_begin, sshfs_write_end,
          0, sf, NULL);
  } else {
    err = sftp_request_iov(SSH_FXP_WRITE, iov, 2, SSH_FXP_STATUS,
               NULL);
  }
  buf_free(&buf);
  return err ? err : (int) size;
}

#if FUSE_VERSION >= 25
static int sshfs_statfs(const char *path, struct statvfs *buf)
{
  (void) path;

  buf->f_namemax = 255;
  buf->f_bsize = sshfs.blksize;
  /*
   * df seems to use f_bsize instead of f_frsize, so make them
   * the same
   */
  buf->f_frsize = buf->f_bsize;
  buf->f_blocks = buf->f_bfree =  buf->f_bavail =
    1000ULL * 1024 * 1024 * 1024 / buf->f_frsize;
  buf->f_files = buf->f_ffree = 1000000000;
  return 0;
}
#else
static int sshfs_statfs(const char *path, struct statfs *buf)
{
  (void) path;

  buf->f_namelen = 255;
  buf->f_bsize = sshfs.blksize;
  buf->f_blocks = buf->f_bfree = buf->f_bavail =
    1000ULL * 1024 * 1024 * 1024 / buf->f_bsize;
  buf->f_files = buf->f_ffree = 1000000000;
  return 0;
}
#endif

#if FUSE_VERSION >= 25
static int sshfs_create(const char *path, mode_t mode,
                        struct fuse_file_info *fi)
{
  return sshfs_open_common(path, mode, fi);
}

static int sshfs_ftruncate(const char *path, off_t size,
                           struct fuse_file_info *fi)
{
  int err;
  struct buffer buf;
  struct sshfs_file *sf = get_sshfs_file(fi);

  (void) path;

  if (!sshfs_file_is_conn(sf))
    return -EIO;

  sshfs.modifver ++;
  if (sshfs.truncate_workaround)
    return sshfs_truncate_workaround(path, size, fi);

  buf_init(&buf, 0);
  buf_add_buf(&buf, &sf->handle);
  buf_add_uint32(&buf, SSH_FILEXFER_ATTR_SIZE);
  buf_add_uint64(&buf, size);
  err = sftp_request(SSH_FXP_FSETSTAT, &buf, SSH_FXP_STATUS, NULL);
  buf_free(&buf);

  return err;
}
#endif

static int sshfs_fgetattr(const char *path, struct stat *stbuf,
        struct fuse_file_info *fi)
{
  int err;
  struct buffer buf;
  struct buffer outbuf;
  struct sshfs_file *sf = get_sshfs_file(fi);

  (void) path;

  if (!sshfs_file_is_conn(sf))
    return -EIO;

  buf_init(&buf, 0);
  buf_add_buf(&buf, &sf->handle);
  err = sftp_request(SSH_FXP_FSTAT, &buf, SSH_FXP_ATTRS, &outbuf);
  if (!err) {
    if (buf_get_attrs(&outbuf, stbuf, NULL) == -1)
      err = -EIO;
    buf_free(&outbuf);
  }
  buf_free(&buf);
  return err;
}

static int sshfs_truncate_zero(const char *path)
{
  int err;
  struct fuse_file_info fi;

  fi.flags = O_WRONLY | O_TRUNC;
  err = sshfs_open(path, &fi);
  if (!err)
    sshfs_release(path, &fi);

  return err;
}

static size_t calc_buf_size(off_t size, off_t offset)
{
  return offset + sshfs.max_read < size ? sshfs.max_read : size - offset;
}

static int sshfs_truncate_shrink(const char *path, off_t size)
{
  int res;
  char *data;
  off_t offset;
  struct fuse_file_info fi;

  data = calloc(size, 1);
  if (!data)
    return -ENOMEM;

  fi.flags = O_RDONLY;
  res = sshfs_open(path, &fi);
  if (res)
    goto out;

  for (offset = 0; offset < size; offset += res) {
    size_t bufsize = calc_buf_size(size, offset);
    res = sshfs_read(path, data + offset, bufsize, offset, &fi);
    if (res <= 0)
      break;
  }
  sshfs_release(path, &fi);
  if (res < 0)
    goto out;

  fi.flags = O_WRONLY | O_TRUNC;
  res = sshfs_open(path, &fi);
  if (res)
    goto out;

  for (offset = 0; offset < size; offset += res) {
    size_t bufsize = calc_buf_size(size, offset);
    res = sshfs_write(path, data + offset, bufsize, offset, &fi);
    if (res < 0)
      break;
  }
  if (res >= 0)
    res = sshfs_flush(path, &fi);
  sshfs_release(path, &fi);

out:
  free(data);
  return res;
}

static int sshfs_truncate_extend(const char *path, off_t size,
                                 struct fuse_file_info *fi)
{
  int res;
  char c = 0;
  struct fuse_file_info tmpfi;
  struct fuse_file_info *openfi = fi;
  if (!fi) {
    openfi = &tmpfi;
    openfi->flags = O_WRONLY;
    res = sshfs_open(path, openfi);
    if (res)
      return res;
  }
  res = sshfs_write(path, &c, 1, size - 1, openfi);
  if (res == 1)
    res = sshfs_flush(path, openfi);
  if (!fi)
    sshfs_release(path, openfi);

  return res;
}

/*
 * Work around broken sftp servers which don't handle
 * SSH_FILEXFER_ATTR_SIZE in SETSTAT request.
 *
 * If new size is zero, just open the file with O_TRUNC.
 *
 * If new size is smaller than current size, then copy file locally,
 * then open/trunc and send it back.
 *
 * If new size is greater than current size, then write a zero byte to
 * the new end of the file.
 */
static int sshfs_truncate_workaround(const char *path, off_t size,
                                     struct fuse_file_info *fi)
{
  if (size == 0)
    return sshfs_truncate_zero(path);
  else {
    struct stat stbuf;
    int err;
    if (fi)
      err = sshfs_fgetattr(path, &stbuf, fi);
    else
      err = sshfs_getattr(path, &stbuf);
    if (err)
      return err;
    if (stbuf.st_size == size)
      return 0;
    else if (stbuf.st_size > size)
      return sshfs_truncate_shrink(path, size);
    else
      return sshfs_truncate_extend(path, size, fi);
  }
}

static int processing_init(void)
{
  pthread_mutex_init(&sshfs.lock, NULL);
  pthread_mutex_init(&sshfs.lock_write, NULL);
  pthread_cond_init(&sshfs.outstanding_cond, NULL);
  sshfs.reqtab = g_hash_table_new(NULL, NULL);
  if (!sshfs.reqtab) {
    fprintf(stderr, "failed to create hash table\n");
    return -1;
  }
  return 0;
}

static struct fuse_cache_operations sshfs_oper = {
  .oper = {
#ifdef SSHFS_USE_INIT
    .init       = sshfs_init,
#endif
    .getattr    = sshfs_getattr,
    .readlink   = sshfs_readlink,
    .mknod      = sshfs_mknod,
    .mkdir      = sshfs_mkdir,
    .symlink    = sshfs_symlink,
    .unlink     = sshfs_unlink,
    .rmdir      = sshfs_rmdir,
    .rename     = sshfs_rename,
    .chmod      = sshfs_chmod,
    .chown      = sshfs_chown,
    .truncate   = sshfs_truncate,
    .utime      = sshfs_utime,
    .open       = sshfs_open,
    .flush      = sshfs_flush,
    .fsync      = sshfs_fsync,
    .release    = sshfs_release,
    .read       = sshfs_read,
    .write      = sshfs_write,
    .statfs     = sshfs_statfs,
#if FUSE_VERSION >= 25
    .create     = sshfs_create,
    .ftruncate  = sshfs_ftruncate,
    .fgetattr   = sshfs_fgetattr,
#endif
  },
  .cache_getdir = sshfs_getdir,
};

static void usage(const char *progname)
{
  fprintf(stderr,
"usage: %s [user@]host:[dir] mountpoint [options]\n"
"\n"
"general options:\n"
"    -o opt,[opt...]        mount options\n"
"    -h   --help            print help\n"
"    -V   --version         print version\n"
"\n"
"SSHFS options:\n"
"    -p PORT                equivalent to '-o port=PORT'\n"
"    -C                     equivalent to '-o compression=yes'\n"
"    -1                     equivalent to '-o ssh_protocol=1'\n"
"    -o reconnect           reconnect to server\n"
"    -o sshfs_sync          synchronous writes\n"
"    -o no_readahead        synchronous reads (no speculative readahead)\n"
"    -o sshfs_debug         print some debugging information\n"
"    -o cache=YESNO         enable caching {yes,no} (default: yes)\n"
"    -o cache_timeout=N     sets timeout for caches in seconds (default: 20)\n"
"    -o cache_X_timeout=N   sets timeout for {stat,dir,link} cache\n"
"    -o workaround=LIST     colon separated list of workarounds\n"
"             none             no workarounds enabled\n"
"             all              all workarounds enabled\n"
"             [no]rename       fix renaming to existing file (default: off)\n"
#ifdef SSH_NODELAY_WORKAROUND
"             [no]nodelay      set nodelay tcp flag in ssh (default: on)\n"
#endif
"             [no]nodelaysrv   set nodelay tcp flag in sshd (default: off)\n"
"             [no]truncate     fix truncate for old servers (default: off)\n"
"             [no]buflimit     fix buffer fillup bug in server (default: on)\n"
"    -o idmap=TYPE          user/group ID mapping, possible types are:\n"
"             none             no translation of the ID space (default)\n"
"             user             only translate UID of connecting user\n"
"    -o ssh_command=CMD     execute CMD instead of 'ssh'\n"
"    -o ssh_protocol=N      ssh protocol to use (default: 2)\n"
"    -o sftp_server=SERV    path to sftp server or subsystem (default: sftp)\n"
"    -o directport=PORT     directly connect to PORT bypassing ssh\n"
"    -o transform_symlinks  transform absolute symlinks to relative\n"
"    -o follow_symlinks     follow symlinks on the server\n"
"    -o no_check_root       don't check for existence of 'dir' on server\n"
"    -o SSHOPT=VAL          ssh options (see man ssh_config)\n"
"\n", progname);
}

static int is_ssh_opt(const char *arg)
{
  if (arg[0] != '-') {
    unsigned arglen = strlen(arg);
    const char **o;
    for (o = ssh_opts; *o; o++) {
      unsigned olen = strlen(*o);
      if (arglen > olen && arg[olen] == '=' &&
          strncasecmp(arg, *o, olen) == 0)
        return 1;
    }
  }
  return 0;
}

static int sshfs_fuse_main(struct fuse_args *args)
{
#if FUSE_VERSION >= 26
  return fuse_main(args->argc, args->argv, cache_init(&sshfs_oper), NULL);
#else
  return fuse_main(args->argc, args->argv, cache_init(&sshfs_oper));
#endif
}

static int sshfs_opt_proc(void *data, const char *arg, int key,
                          struct fuse_args *outargs)
{
  char *tmp;
  (void) data;

  switch (key) {
  case FUSE_OPT_KEY_OPT:
    if (is_ssh_opt(arg)) {
      tmp = g_strdup_printf("-o%s", arg);
      ssh_add_arg(tmp);
      g_free(tmp);
      return 0;
    }
    return 1;

  case FUSE_OPT_KEY_NONOPT:
    if (!sshfs.host && strchr(arg, ':')) {
      sshfs.host = strdup(arg);
      return 0;
    }
    return 1;

  case KEY_PORT:
    tmp = g_strdup_printf("-oPort=%s", arg + 2);
    ssh_add_arg(tmp);
    g_free(tmp);
    return 0;

  case KEY_COMPRESS:
    ssh_add_arg("-oCompression=yes");
    return 0;

  case KEY_HELP:
    usage(outargs->argv[0]);
    fuse_opt_add_arg(outargs, "-ho");
    sshfs_fuse_main(outargs);
    exit(1);

  case KEY_VERSION:
    fprintf(stderr, "SSHFS version %s\n", PACKAGE_VERSION);
#if FUSE_VERSION >= 25
    fuse_opt_add_arg(outargs, "--version");
    sshfs_fuse_main(outargs);
#endif
    exit(0);

  default:
    fprintf(stderr, "internal error\n");
    abort();
  }
}

static int workaround_opt_proc(void *data, const char *arg, int key,
             struct fuse_args *outargs)
{
  (void) data; (void) key; (void) outargs;
  fprintf(stderr, "unknown workaround: '%s'\n", arg);
  return -1;
}

int parse_workarounds(void)
{
  int res;
  char *argv[] = { "", "-o", sshfs.workarounds, NULL };
  struct fuse_args args = FUSE_ARGS_INIT(3, argv);
  char *s = sshfs.workarounds;
  if (!s)
    return 0;

  while ((s = strchr(s, ':')))
    *s = ',';

  res = fuse_opt_parse(&args, &sshfs, workaround_opts,
           workaround_opt_proc);
  fuse_opt_free_args(&args);

  return res;
}

#if FUSE_VERSION == 25
static int fuse_opt_insert_arg(struct fuse_args *args, int pos,
                               const char *arg)
{
  assert(pos <= args->argc);
  if (fuse_opt_add_arg(args, arg) == -1)
    return -1;

  if (pos != args->argc - 1) {
    char *newarg = args->argv[args->argc - 1];
    memmove(&args->argv[pos + 1], &args->argv[pos],
      sizeof(char *) * (args->argc - pos - 1));
    args->argv[pos] = newarg;
  }
  return 0;
}
#endif

void check_large_read(struct fuse_args *args)
{
  struct utsname buf;
  int err = uname(&buf);
  if (!err && strcmp(buf.sysname, "Linux") == 0 &&
      strncmp(buf.release, "2.4.", 4) == 0)
    fuse_opt_insert_arg(args, 1, "-olarge_read");
}

int main(int argc, char *argv[])
{
  int res;
  struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
  char *tmp;
  char *fsname;
  char *base_path;
  const char *sftp_server;
  int libver;

  g_thread_init(NULL);

  sshfs.blksize = 4096;
  sshfs.max_read = 65536;
  sshfs.nodelay_workaround = 1;
  sshfs.nodelaysrv_workaround = 0;
  sshfs.rename_workaround = 0;
  sshfs.truncate_workaround = 0;
  sshfs.buflimit_workaround = 1;
  sshfs.ssh_ver = 2;
  sshfs.progname = argv[0];
  ssh_add_arg("ssh");
  ssh_add_arg("-x");
  ssh_add_arg("-a");
  ssh_add_arg("-oClearAllForwardings=yes");

  if (fuse_opt_parse(&args, &sshfs, sshfs_opts, sshfs_opt_proc) == -1 ||
      parse_workarounds() == -1)
    exit(1);

  if (sshfs.buflimit_workaround)
    /* Work around buggy sftp-server in OpenSSH.  Without this on
       a slow server a 10Mbyte buffer would fill up and the server
       would abort */
    sshfs.max_outstanding_len = 8388608;
  else
    sshfs.max_outstanding_len = ~0;

  if (!sshfs.host) {
    fprintf(stderr, "missing host\n");
    fprintf(stderr, "see `%s -h' for usage\n", argv[0]);
    exit(1);
  }

  fsname = g_strdup(sshfs.host);
  base_path = strchr(sshfs.host, ':');
  *base_path++ = '\0';
  if (base_path[0] && base_path[strlen(base_path)-1] != '/')
    sshfs.base_path = g_strdup_printf("%s/", base_path);
  else
    sshfs.base_path = g_strdup(base_path);

  if (sshfs.ssh_command) {
    free(sshfs.ssh_args.argv[0]);
    sshfs.ssh_args.argv[0] = sshfs.ssh_command;
  }

  tmp = g_strdup_printf("-%i", sshfs.ssh_ver);
  ssh_add_arg(tmp);
  g_free(tmp);
  ssh_add_arg(sshfs.host);
  if (sshfs.sftp_server)
    sftp_server = sshfs.sftp_server;
  else if (sshfs.ssh_ver == 1)
    sftp_server = SFTP_SERVER_PATH;
  else
    sftp_server = "sftp";

  if (sshfs.ssh_ver != 1 && strchr(sftp_server, '/') == NULL)
    ssh_add_arg("-s");

  ssh_add_arg(sftp_server);
  free(sshfs.sftp_server);

  res = processing_init();
  if (res == -1)
    exit(1);

  if (connect_remote() == -1)
    exit(1);

#ifndef SSHFS_USE_INIT
  if (sshfs.detect_uid)
    sftp_detect_uid();
#endif

  if (!sshfs.no_check_root && sftp_check_root(base_path) == -1)
    exit(1);

  res = cache_parse_options(&args);
  if (res == -1)
    exit(1);

  sshfs.randseed = time(0);

  if (sshfs.max_read > 65536)
    sshfs.max_read = 65536;

  if (fuse_is_lib_option("ac_attr_timeout="))
    fuse_opt_insert_arg(&args, 1, "-oauto_cache,ac_attr_timeout=0");
  tmp = g_strdup_printf("-omax_read=%u", sshfs.max_read);
  fuse_opt_insert_arg(&args, 1, tmp);
  g_free(tmp);
#if FUSE_VERSION >= 27
  libver = fuse_version();
  assert(libver >= 27);
  tmp = g_strdup_printf("-osubtype=sshfs,fsname=%s", fsname);
#else
  tmp = g_strdup_printf("-ofsname=sshfs#%s", fsname);
#endif
  fuse_opt_insert_arg(&args, 1, tmp);
  g_free(tmp);
  g_free(fsname);
  check_large_read(&args);
  res = sshfs_fuse_main(&args);
  fuse_opt_free_args(&args);
  fuse_opt_free_args(&sshfs.ssh_args);
  free(sshfs.directport);

  return res;
}