path: root/sshfs.c

/*
  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.
*/

#define _GNU_SOURCE /* avoid implicit declaration of *pt* functions */
#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/types.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <glib.h>

#include "cache.h"

#ifndef MAP_LOCKED
#define MAP_LOCKED 0
#endif

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif


#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

/* statvfs@openssh.com f_flag flags */
#define SSH2_FXE_STATVFS_ST_RDONLY	0x00000001
#define SSH2_FXE_STATVFS_ST_NOSUID	0x00000002

#define SFTP_EXT_POSIX_RENAME "posix-rename@openssh.com"
#define SFTP_EXT_STATVFS "statvfs@openssh.com"

#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 max_write;
	unsigned ssh_ver;
	int sync_write;
	int sync_read;
	int debug;
	int foreground;
	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 ptyfd;
	int ptyslavefd;
	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;
	int password_stdin;
	char *password;
	int ext_posix_rename;
	int ext_statvfs;

	/* statistics */
	uint64_t bytes_sent;
	uint64_t bytes_received;
	uint64_t num_sent;
	uint64_t num_received;
	unsigned int min_rtt;
	unsigned int max_rtt;
	uint64_t total_rtt;
	unsigned int num_connect;
};

static struct sshfs sshfs;

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

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

#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("max_write=%u",      max_write, 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),
	SSHFS_OPT("password_stdin",    password_stdin, 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_KEY("debug",          KEY_FOREGROUND),
	FUSE_OPT_KEY("-d",             KEY_FOREGROUND),
	FUSE_OPT_KEY("-f",             KEY_FOREGROUND),
	FUSE_OPT_KEY("-F ",            KEY_CONFIGFILE),
	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) &
			~((unsigned long long) 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_statvfs(struct buffer *buf, struct statvfs *stbuf)
{
	uint64_t bsize;
	uint64_t frsize;
	uint64_t blocks;
	uint64_t bfree;
	uint64_t bavail;
	uint64_t files;
	uint64_t ffree;
	uint64_t favail;
	uint64_t fsid;
	uint64_t flag;
	uint64_t namemax;

	if (buf_get_uint64(buf, &bsize) == -1 ||
	    buf_get_uint64(buf, &frsize) == -1 ||
	    buf_get_uint64(buf, &blocks) == -1 ||
	    buf_get_uint64(buf, &bfree) == -1 ||
	    buf_get_uint64(buf, &bavail) == -1 ||
	    buf_get_uint64(buf, &files) == -1 ||
	    buf_get_uint64(buf, &ffree) == -1 ||
	    buf_get_uint64(buf, &favail) == -1 ||
	    buf_get_uint64(buf, &fsid) == -1 ||
	    buf_get_uint64(buf, &flag) == -1 ||
	    buf_get_uint64(buf, &namemax) == -1) {
		return -1;
	}

	memset(stbuf, 0, sizeof(struct statvfs));
	stbuf->f_bsize = bsize;
	stbuf->f_frsize = frsize;
	stbuf->f_blocks = blocks;
	stbuf->f_bfree = bfree;
	stbuf->f_bavail = bavail;
	stbuf->f_files = files;
	stbuf->f_ffree = ffree;
	stbuf->f_favail = favail;
	stbuf->f_namemax = namemax;

	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 pty_expect_loop(void)
{
	int res;
	char buf[256];
	const char *passwd_str = "assword:";
	int timeout = 60 * 1000; /* 1min timeout for the prompt to appear */
	int passwd_len = strlen(passwd_str);
	int len = 0;
	char c;

	while (1) {
		struct pollfd fds[2];

		fds[0].fd = sshfs.fd;
		fds[0].events = POLLIN;
		fds[1].fd = sshfs.ptyfd;
		fds[1].events = POLLIN;
		res = poll(fds, 2, timeout);
		if (res == -1) {
			perror("poll");
			return -1;
		}
		if (res == 0) {
			fprintf(stderr, "Timeout waiting for prompt\n");
			return -1;
		}
		if (fds[0].revents) {
			/*
			 * Something happened on stdout of ssh, this
			 * either means, that we are connected, or
			 * that we are disconnected.  In any case the
			 * password doesn't matter any more.
			 */
			break;
		}

		res = read(sshfs.ptyfd, &c, 1);
		if (res == -1) {
			perror("read");
			return -1;
		}
		if (res == 0) {
			fprintf(stderr, "EOF while waiting for prompt\n");
			return -1;
		}
		buf[len] = c;
		len++;
		if (len == passwd_len) {
			if (memcmp(buf, passwd_str, passwd_len) == 0) {
				write(sshfs.ptyfd, sshfs.password,
				      strlen(sshfs.password));
			}
			memmove(buf, buf + 1, passwd_len - 1);
			len--;
		}
	}

	if (!sshfs.reconnect) {
		size_t size = getpagesize();

		memset(sshfs.password, 0, size);
		munmap(sshfs.password, size);
		sshfs.password = NULL;
	}

	return 0;
}

static int pty_master(char **name)
{
	int mfd;

	mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
	if (mfd == -1) {
		perror("failed to open pty");
		return -1;
	}
	if (grantpt(mfd) != 0) {
		perror("grantpt");
		return -1;
	}
	if (unlockpt(mfd) != 0) {
		perror("unlockpt");
		return -1;
	}
	*name = ptsname(mfd);

	return mfd;
}

static void replace_arg(char **argp, const char *newarg)
{
	free(*argp);
	*argp = strdup(newarg);
	if (*argp == NULL) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
}

static int start_ssh(void)
{
	char *ptyname = NULL;
	int sockpair[2];
	int pid;

	if (sshfs.password_stdin) {

		sshfs.ptyfd = pty_master(&ptyname);
		if (sshfs.ptyfd == -1)
			return -1;

		sshfs.ptyslavefd = open(ptyname, O_RDWR | O_NOCTTY);
		if (sshfs.ptyslavefd == -1)
			return -1;
	}

	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");
		close(sockpair[1]);
		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) {
			int i;
			/*
			 * Hack to work around missing TCP_NODELAY
			 * setting in sshd
			 */
			for (i = 1; i < sshfs.ssh_args.argc; i++) {
				if (strcmp(sshfs.ssh_args.argv[i], "-x") == 0) {
					replace_arg(&sshfs.ssh_args.argv[i],
						    "-X");
					break;
				}
			}
		}

		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.foreground && 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("/");

		if (sshfs.password_stdin) {
			int sfd;

			setsid();
			sfd = open(ptyname, O_RDWR);
			if (sfd == -1) {
				perror(ptyname);
				_exit(1);
			}
			close(sfd);
			close(sshfs.ptyslavefd);
			close(sshfs.ptyfd);
		}

		if (sshfs.debug) {
			int i;

			fprintf(stderr, "executing");
			for (i = 0; i < sshfs.ssh_args.argc; i++)
				fprintf(stderr, " <%s>",
					sshfs.ssh_args.argv[i]);
			fprintf(stderr, "\n");
		}

		execvp(sshfs.ssh_args.argv[0], sshfs.ssh_args.argv);
		fprintf(stderr, "failed to execute '%s': %s\n",
			sshfs.ssh_args.argv[0], strerror(errno));
		_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;
			unsigned msgsize = buf.size + 5;

			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), msgsize, difftime);

			if (difftime < sshfs.min_rtt || !sshfs.num_received)
				sshfs.min_rtt = difftime;
			if (difftime > sshfs.max_rtt)
				sshfs.max_rtt = difftime;
			sshfs.total_rtt += difftime;
			sshfs.num_received++;
			sshfs.bytes_received += msgsize;
		}
		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 close_conn(void)
{
	close(sshfs.fd);
	sshfs.fd = -1;
	if (sshfs.ptyfd != -1) {
		close(sshfs.ptyfd);
		sshfs.ptyfd = -1;
	}
	if (sshfs.ptyslavefd != -1) {
		close(sshfs.ptyslavefd);
		sshfs.ptyslavefd = -1;
	}
}

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_conn();
		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;

	DEBUG("Server version: %u\n", *version);

	if (len > 5) {
		struct buffer buf2;

		buf_init(&buf2, len - 5);
		if (do_read(&buf2) == -1)
			return -1;

		do {
			char *ext;
			char *extdata;

			if (buf_get_string(&buf2, &ext) == -1 ||
			    buf_get_string(&buf2, &extdata) == -1)
				return -1;

			DEBUG("Extension: %s <%s>\n", ext, extdata);

			if (strcmp(ext, SFTP_EXT_POSIX_RENAME) == 0 &&
			    strcmp(extdata, "1") == 0) {
				sshfs.ext_posix_rename = 1;
				sshfs.rename_workaround = 0;
			}
			if (strcmp(ext, SFTP_EXT_STATVFS) == 0 &&
			    strcmp(extdata, "2") == 0)
				sshfs.ext_statvfs = 1;
		} while (buf2.len < buf2.size);
	}
	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 (sshfs.password_stdin && pty_expect_loop() == -1)
		goto out;

	if (sftp_find_init_reply(&version) == -1)
		goto out;

	sshfs.server_version = 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();

	if (err)
		close_conn();
	else
		sshfs.num_connect++;

	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);
		sshfs.num_sent++;
		sshfs.bytes_sent += req->len;
	}
	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 int sshfs_ext_posix_rename(const char *from, const char *to)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_string(&buf, SFTP_EXT_POSIX_RENAME);
	buf_add_path(&buf, from);
	buf_add_path(&buf, to);
	err = sftp_request(SSH_FXP_EXTENDED, &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;
	if (sshfs.ext_posix_rename)
		err = sshfs_ext_posix_rename(from, to);
	else
		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;
	uint64_t wrctr = cache_get_write_ctr();

	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, wrctr);
		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;
}

static int sshfs_ext_statvfs(const char *path, struct statvfs *stbuf)
{
	int err;
	struct buffer buf;
	struct buffer outbuf;
	buf_init(&buf, 0);
	buf_add_string(&buf, SFTP_EXT_STATVFS);
	buf_add_path(&buf, path);
	err = sftp_request(SSH_FXP_EXTENDED, &buf, SSH_FXP_EXTENDED_REPLY,
			   &outbuf);
	if (!err) {
		if (buf_get_statvfs(&outbuf, stbuf) == -1)
			err = -EIO;
		buf_free(&outbuf);
	}
	buf_free(&buf);
	return err;
}


#if FUSE_VERSION >= 25
static int sshfs_statfs(const char *path, struct statvfs *buf)
{
	if (sshfs.ext_statvfs)
		return sshfs_ext_statvfs(path, buf);

	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)
{
	if (sshfs.ext_statvfs) {
		int err;
		struct statvfs vbuf;

		err = sshfs_ext_statvfs(path, &vbuf);
		if (!err) {
			buf->f_bsize = vbuf.f_bsize;
			buf->f_blocks = vbuf.f_blocks;
			buf->f_bfree = vbuf.f_bfree;
			buf->f_bavail = vbuf.f_bavail;
			buf->f_files = vbuf.f_files;
			buf->f_ffree = vbuf.f_ffree;
			buf->f_namelen = vbuf.f_namemax;
		}
		return err;
	}

	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)
{
	signal(SIGPIPE, SIG_IGN);

	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"
"    -F ssh_configfile      specifies alternative ssh configuration file\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 password_stdin      read password from stdin (only for pam_mount!)\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_CONFIGFILE:
		tmp = g_strdup_printf("-F%s", arg + 2);
		ssh_add_arg(tmp);
		g_free(tmp);
		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);

	case KEY_FOREGROUND:
		sshfs.foreground = 1;
		return 1;

	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

static 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");
}

static int read_password(void)
{
	int size = getpagesize();
	int max_password = 64;
	int n;

	sshfs.password = mmap(NULL, size, PROT_READ | PROT_WRITE,
			      MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED,
			      -1, 0);
	if (sshfs.password == MAP_FAILED) {
		perror("Failed to allocate locked page for password");
		return -1;
	}

	/* Don't use fgets() because password might stay in memory */
	for (n = 0; n < max_password; n++) {
		int res;

		res = read(0, &sshfs.password[n], 1);
		if (res == -1) {
			perror("Reading password");
			return -1;
		}
		if (res == 0) {
			sshfs.password[n] = '\n';
			break;
		}
		if (sshfs.password[n] == '\n')
			break;
	}
	if (n == max_password) {
		fprintf(stderr, "Password too long\n");
		return -1;
	}
	sshfs.password[n+1] = '\0';
	ssh_add_arg("-oNumberOfPasswordPrompts=1");
	ssh_add_arg("-oPreferredAuthentications=password,keyboard-interactive");

	return 0;
}

static void set_ssh_command(void)
{
	char *s;
	char *d;
	int i = 0;
	int end = 0;

	d = sshfs.ssh_command;
	s = sshfs.ssh_command;
	while (!end) {
		switch (*s) {
		case '\0':
			end = 1;
		case ' ':
			*d = '\0';
			if (i == 0) {
				replace_arg(&sshfs.ssh_args.argv[0],
					    sshfs.ssh_command);
			} else {
				if (fuse_opt_insert_arg(&sshfs.ssh_args, i, 
						sshfs.ssh_command) == -1)
					_exit(1);
			}
			i++;
			d = sshfs.ssh_command;
			break;

		case '\\':
			if (s[1])
				s++;
		default:
			*d++ = *s;
		}
		s++;
	}
}

static char *find_base_path(void)
{
	char *s = sshfs.host;
	char *d = s;

	for (; *s && *s != ':'; s++) {
		if (*s == '[') {
			/*
			 * Handle IPv6 numerical address enclosed in square
			 * brackets
			 */
			s++;
			for (; *s != ']'; s++) {
				if (!*s) {
					fprintf(stderr,	"missing ']' in hostname\n");
					exit(1);
				}
				*d++ = *s;
			}
		} else {
			*d++ = *s;
		}

	}
	*d++ = '\0';
	s++;

	return s;
}

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.max_write = 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];
	sshfs.fd = -1;
	sshfs.ptyfd = -1;
	sshfs.ptyslavefd = -1;
	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);

	DEBUG("SSHFS version %s\n", PACKAGE_VERSION);

	if (sshfs.password_stdin) {
		res = read_password();
		if (res == -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 = find_base_path();
	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)
		set_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 (sshfs.max_write > 65536)
		sshfs.max_write = 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);
	tmp = g_strdup_printf("-omax_write=%u", sshfs.max_write);
	fuse_opt_insert_arg(&args, 1, tmp);
	g_free(tmp);
	/*
	 * Remove commas from fsname, as it confuses the fuse option
	 * parser.
	 *
	 * FIXME: escape commas instead.  Needs support in libfuse.
	 */
	if (strchr(fsname, ',') != NULL) {
		char *s = fsname;
		char *d = s;

		for (; *s; s++) {
			if (*s != ',')
				*d++ = *s;
		}
		*d = *s;
	}
#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);

	if (sshfs.debug) {
		unsigned int avg_rtt = 0;

		if (sshfs.num_sent)
			avg_rtt = sshfs.total_rtt / sshfs.num_sent;

		DEBUG("\n"
		      "sent:               %llu messages, %llu bytes\n"
		      "received:           %llu messages, %llu bytes\n"
		      "rtt min/max/avg:    %ums/%ums/%ums\n"
		      "num connect:        %u\n",
		      (unsigned long long) sshfs.num_sent,
		      (unsigned long long) sshfs.bytes_sent,
		      (unsigned long long) sshfs.num_received,
		      (unsigned long long) sshfs.bytes_received,
		      sshfs.min_rtt, sshfs.max_rtt, avg_rtt,
		      sshfs.num_connect);
	}

	fuse_opt_free_args(&args);
	fuse_opt_free_args(&sshfs.ssh_args);
	free(sshfs.directport);

	return res;
}