psftp.c

/*
 * psftp.c: (platform-independent) front end for PSFTP.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <limits.h>

#define PUTTY_DO_GLOBALS
#include "putty.h"
#include "psftp.h"
#include "storage.h"
#include "ssh.h"
#include "sftp.h"
#include "int64.h"

const char *const appname = "PSFTP";

/*
 * Since SFTP is a request-response oriented protocol, it requires
 * no buffer management: when we send data, we stop and wait for an
 * acknowledgement _anyway_, and so we can't possibly overfill our
 * send buffer.
 */

static int psftp_connect(char *userhost, char *user, int portnumber);
static int do_sftp_init(void);
void do_sftp_cleanup();

/* ----------------------------------------------------------------------
 * sftp client state.
 */

char *pwd, *homedir;
static Backend *back;
static void *backhandle;
static Conf *conf;
int sent_eof = FALSE;

/* ----------------------------------------------------------------------
 * Manage sending requests and waiting for replies.
 */
struct sftp_packet *sftp_wait_for_reply(struct sftp_request *req)
{
  struct sftp_packet *pktin;
  struct sftp_request *rreq;

  sftp_register(req);
  pktin = sftp_recv();
  if (pktin == NULL)
    connection_fatal(NULL,
                     "did not receive SFTP response packet "
                     "from server");
  rreq = sftp_find_request(pktin);
  if (rreq != req)
    connection_fatal(NULL,
                     "unable to understand SFTP response packet "
                     "from server: %s",
                     fxp_error());
  return pktin;
}

/* ----------------------------------------------------------------------
 * Higher-level helper functions used in commands.
 */

/*
 * Attempt to canonify a pathname starting from the pwd. If
 * canonification fails, at least fall back to returning a _valid_
 * pathname (though it may be ugly, eg /home/simon/../foobar).
 */
char *canonify(const char *name)
{
  char *fullname, *canonname;
  struct sftp_packet *pktin;
  struct sftp_request *req;

  if (name[0] == '/') {
    fullname = dupstr(name);
  } else {
    const char *slash;
    if (pwd[strlen(pwd) - 1] == '/')
      slash = "";
    else
      slash = "/";
    fullname = dupcat(pwd, slash, name, NULL);
  }

  req = fxp_realpath_send(fullname);
  pktin = sftp_wait_for_reply(req);
  canonname = fxp_realpath_recv(pktin, req);

  if (canonname) {
    sfree(fullname);
    return canonname;
  } else {
    /*
     * Attempt number 2. Some FXP_REALPATH implementations
     * (glibc-based ones, in particular) require the _whole_
     * path to point to something that exists, whereas others
     * (BSD-based) only require all but the last component to
     * exist. So if the first call failed, we should strip off
     * everything from the last slash onwards and try again,
     * then put the final component back on.
     *
     * Special cases:
     *
     *  - if the last component is "/." or "/..", then we don't
     *    bother trying this because there's no way it can work.
     *
     *  - if the thing actually ends with a "/", we remove it
     *    before we start. Except if the string is "/" itself
     *    (although I can't see why we'd have got here if so,
     *    because surely "/" would have worked the first
     *    time?), in which case we don't bother.
     *
     *  - if there's no slash in the string at all, give up in
     *    confusion (we expect at least one because of the way
     *    we constructed the string).
     */

    int i;
    char *returnname;

    i = strlen(fullname);
    if (i > 2 && fullname[i - 1] == '/')
      fullname[--i] = '\0'; /* strip trailing / unless at pos 0 */
    while (i > 0 && fullname[--i] != '/')
      ;

    /*
     * Give up on special cases.
     */
    if (fullname[i] != '/' ||           /* no slash at all */
        !strcmp(fullname + i, "/.") ||  /* ends in /. */
        !strcmp(fullname + i, "/..") || /* ends in /.. */
        !strcmp(fullname, "/")) {
      return fullname;
    }

    /*
     * Now i points at the slash. Deal with the final special
     * case i==0 (ie the whole path was "/nonexistentfile").
     */
    fullname[i] = '\0'; /* separate the string */
    if (i == 0) {
      req = fxp_realpath_send("/");
    } else {
      req = fxp_realpath_send(fullname);
    }
    pktin = sftp_wait_for_reply(req);
    canonname = fxp_realpath_recv(pktin, req);

    if (!canonname) {
      /* Even that failed. Restore our best guess at the
       * constructed filename and give up */
      fullname[i] = '/'; /* restore slash and last component */
      return fullname;
    }

    /*
     * We have a canonical name for all but the last path
     * component. Concatenate the last component and return.
     */
    returnname = dupcat(canonname,
                        canonname[strlen(canonname) - 1] == '/' ? "" : "/",
                        fullname + i + 1,
                        NULL);
    sfree(fullname);
    sfree(canonname);
    return returnname;
  }
}

/*
 * qsort comparison routine for fxp_name structures. Sorts by real
 * file name.
 */
static int sftp_name_compare(const void *av, const void *bv)
{
  const struct fxp_name *const *a = (const struct fxp_name *const *)av;
  const struct fxp_name *const *b = (const struct fxp_name *const *)bv;
  return strcmp((*a)->filename, (*b)->filename);
}

/*
 * Likewise, but for a bare char *.
 */
static int bare_name_compare(const void *av, const void *bv)
{
  const char **a = (const char **)av;
  const char **b = (const char **)bv;
  return strcmp(*a, *b);
}

static void not_connected(void)
{
  printf("psftp: not connected to a host; use \"open host.name\"\n");
}

/* ----------------------------------------------------------------------
 * The meat of the `get' and `put' commands.
 */
int sftp_get_file(char *fname, char *outfname, int recurse, int restart)
{
  struct fxp_handle *fh;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  struct fxp_xfer *xfer;
  uint64 offset;
  WFile *file;
  int ret, shown_err = FALSE;
  struct fxp_attrs attrs;

  /*
   * In recursive mode, see if we're dealing with a directory.
   * (If we're not in recursive mode, we need not even check: the
   * subsequent FXP_OPEN will return a usable error message.)
   */
  if (recurse) {
    int result;

    req = fxp_stat_send(fname);
    pktin = sftp_wait_for_reply(req);
    result = fxp_stat_recv(pktin, req, &attrs);

    if (result && (attrs.flags & SSH_FILEXFER_ATTR_PERMISSIONS) &&
        (attrs.permissions & 0040000)) {

      struct fxp_handle *dirhandle;
      int nnames, namesize;
      struct fxp_name **ournames;
      struct fxp_names *names;
      int i;

      /*
       * First, attempt to create the destination directory,
       * unless it already exists.
       */
      if (file_type(outfname) != FILE_TYPE_DIRECTORY &&
          !create_directory(outfname)) {
        printf("%s: Cannot create directory\n", outfname);
        return 0;
      }

      /*
       * Now get the list of filenames in the remote
       * directory.
       */
      req = fxp_opendir_send(fname);
      pktin = sftp_wait_for_reply(req);
      dirhandle = fxp_opendir_recv(pktin, req);

      if (!dirhandle) {
        printf("%s: unable to open directory: %s\n", fname, fxp_error());
        return 0;
      }
      nnames = namesize = 0;
      ournames = NULL;
      while (1) {
        int i;

        req = fxp_readdir_send(dirhandle);
        pktin = sftp_wait_for_reply(req);
        names = fxp_readdir_recv(pktin, req);

        if (names == NULL) {
          if (fxp_error_type() == SSH_FX_EOF)
            break;
          printf("%s: reading directory: %s\n", fname, fxp_error());

          req = fxp_close_send(dirhandle);
          pktin = sftp_wait_for_reply(req);
          fxp_close_recv(pktin, req);

          sfree(ournames);
          return 0;
        }
        if (names->nnames == 0) {
          fxp_free_names(names);
          break;
        }
        if (nnames + names->nnames >= namesize) {
          namesize += names->nnames + 128;
          ournames = sresize(ournames, namesize, struct fxp_name *);
        }
        for (i = 0; i < names->nnames; i++)
          if (strcmp(names->names[i].filename, ".") &&
              strcmp(names->names[i].filename, "..")) {
            if (!vet_filename(names->names[i].filename)) {
              printf("ignoring potentially dangerous server-"
                     "supplied filename '%s'\n",
                     names->names[i].filename);
            } else {
              ournames[nnames++] = fxp_dup_name(&names->names[i]);
            }
          }
        fxp_free_names(names);
      }
      req = fxp_close_send(dirhandle);
      pktin = sftp_wait_for_reply(req);
      fxp_close_recv(pktin, req);

      /*
       * Sort the names into a clear order. This ought to
       * make things more predictable when we're doing a
       * reget of the same directory, just in case two
       * readdirs on the same remote directory return a
       * different order.
       */
      if (nnames > 0)
        qsort(ournames, nnames, sizeof(*ournames), sftp_name_compare);

      /*
       * If we're in restart mode, find the last filename on
       * this list that already exists. We may have to do a
       * reget on _that_ file, but shouldn't have to do
       * anything on the previous files.
       *
       * If none of them exists, of course, we start at 0.
       */
      i = 0;
      if (restart) {
        while (i < nnames) {
          char *nextoutfname;
          int ret;
          nextoutfname = dir_file_cat(outfname, ournames[i]->filename);
          ret = (file_type(nextoutfname) == FILE_TYPE_NONEXISTENT);
          sfree(nextoutfname);
          if (ret)
            break;
          i++;
        }
        if (i > 0)
          i--;
      }

      /*
       * Now we're ready to recurse. Starting at ournames[i]
       * and continuing on to the end of the list, we
       * construct a new source and target file name, and
       * call sftp_get_file again.
       */
      for (; i < nnames; i++) {
        char *nextfname, *nextoutfname;
        int ret;

        nextfname = dupcat(fname, "/", ournames[i]->filename, NULL);
        nextoutfname = dir_file_cat(outfname, ournames[i]->filename);
        ret = sftp_get_file(nextfname, nextoutfname, recurse, restart);
        restart = FALSE; /* after first partial file, do full */
        sfree(nextoutfname);
        sfree(nextfname);
        if (!ret) {
          for (i = 0; i < nnames; i++) {
            fxp_free_name(ournames[i]);
          }
          sfree(ournames);
          return 0;
        }
      }

      /*
       * Done this recursion level. Free everything.
       */
      for (i = 0; i < nnames; i++) {
        fxp_free_name(ournames[i]);
      }
      sfree(ournames);

      return 1;
    }
  }

  req = fxp_stat_send(fname);
  pktin = sftp_wait_for_reply(req);
  if (!fxp_stat_recv(pktin, req, &attrs))
    attrs.flags = 0;

  req = fxp_open_send(fname, SSH_FXF_READ, NULL);
  pktin = sftp_wait_for_reply(req);
  fh = fxp_open_recv(pktin, req);

  if (!fh) {
    printf("%s: open for read: %s\n", fname, fxp_error());
    return 0;
  }

  if (restart) {
    file = open_existing_wfile(outfname, NULL);
  } else {
    file = open_new_file(outfname, GET_PERMISSIONS(attrs));
  }

  if (!file) {
    printf("local: unable to open %s\n", outfname);

    req = fxp_close_send(fh);
    pktin = sftp_wait_for_reply(req);
    fxp_close_recv(pktin, req);

    return 0;
  }

  if (restart) {
    char decbuf[30];
    if (seek_file(file, uint64_make(0, 0), FROM_END) == -1) {
      close_wfile(file);
      printf("reget: cannot restart %s - file too large\n", outfname);
      req = fxp_close_send(fh);
      pktin = sftp_wait_for_reply(req);
      fxp_close_recv(pktin, req);

      return 0;
    }

    offset = get_file_posn(file);
    uint64_decimal(offset, decbuf);
    printf("reget: restarting at file position %s\n", decbuf);
  } else {
    offset = uint64_make(0, 0);
  }

  printf("remote:%s => local:%s\n", fname, outfname);

  /*
   * FIXME: we can use FXP_FSTAT here to get the file size, and
   * thus put up a progress bar.
   */
  ret = 1;
  xfer = xfer_download_init(fh, offset);
  while (!xfer_done(xfer)) {
    void *vbuf;
    int len;
    int wpos, wlen;

    xfer_download_queue(xfer);
    pktin = sftp_recv();
    ret = xfer_download_gotpkt(xfer, pktin);
    if (ret <= 0) {
      if (!shown_err) {
        printf("error while reading: %s\n", fxp_error());
        shown_err = TRUE;
      }
      if (ret == INT_MIN) /* pktin not even freed */
        sfree(pktin);
      ret = 0;
    }

    while (xfer_download_data(xfer, &vbuf, &len)) {
      unsigned char *buf = (unsigned char *)vbuf;

      wpos = 0;
      while (wpos < len) {
        wlen = write_to_file(file, buf + wpos, len - wpos);
        if (wlen <= 0) {
          printf("error while writing local file\n");
          ret = 0;
          xfer_set_error(xfer);
          break;
        }
        wpos += wlen;
      }
      if (wpos < len) { /* we had an error */
        ret = 0;
        xfer_set_error(xfer);
      }

      sfree(vbuf);
    }
  }

  xfer_cleanup(xfer);

  close_wfile(file);

  req = fxp_close_send(fh);
  pktin = sftp_wait_for_reply(req);
  fxp_close_recv(pktin, req);

  return ret;
}

int sftp_put_file(char *fname, char *outfname, int recurse, int restart)
{
  struct fxp_handle *fh;
  struct fxp_xfer *xfer;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  uint64 offset;
  RFile *file;
  int err = 0, eof;
  struct fxp_attrs attrs;
  long permissions;

  /*
   * In recursive mode, see if we're dealing with a directory.
   * (If we're not in recursive mode, we need not even check: the
   * subsequent fopen will return an error message.)
   */
  if (recurse && file_type(fname) == FILE_TYPE_DIRECTORY) {
    int result;
    int nnames, namesize;
    char *name, **ournames;
    DirHandle *dh;
    int i;

    /*
     * First, attempt to create the destination directory,
     * unless it already exists.
     */
    req = fxp_stat_send(outfname);
    pktin = sftp_wait_for_reply(req);
    result = fxp_stat_recv(pktin, req, &attrs);
    if (!result || !(attrs.flags & SSH_FILEXFER_ATTR_PERMISSIONS) ||
        !(attrs.permissions & 0040000)) {
      req = fxp_mkdir_send(outfname);
      pktin = sftp_wait_for_reply(req);
      result = fxp_mkdir_recv(pktin, req);

      if (!result) {
        printf("%s: create directory: %s\n", outfname, fxp_error());
        return 0;
      }
    }

    /*
     * Now get the list of filenames in the local directory.
     */
    nnames = namesize = 0;
    ournames = NULL;

    dh = open_directory(fname);
    if (!dh) {
      printf("%s: unable to open directory\n", fname);
      return 0;
    }
    while ((name = read_filename(dh)) != NULL) {
      if (nnames >= namesize) {
        namesize += 128;
        ournames = sresize(ournames, namesize, char *);
      }
      ournames[nnames++] = name;
    }
    close_directory(dh);

    /*
     * Sort the names into a clear order. This ought to make
     * things more predictable when we're doing a reput of the
     * same directory, just in case two readdirs on the same
     * local directory return a different order.
     */
    if (nnames > 0)
      qsort(ournames, nnames, sizeof(*ournames), bare_name_compare);

    /*
     * If we're in restart mode, find the last filename on this
     * list that already exists. We may have to do a reput on
     * _that_ file, but shouldn't have to do anything on the
     * previous files.
     *
     * If none of them exists, of course, we start at 0.
     */
    i = 0;
    if (restart) {
      while (i < nnames) {
        char *nextoutfname;
        nextoutfname = dupcat(outfname, "/", ournames[i], NULL);
        req = fxp_stat_send(nextoutfname);
        pktin = sftp_wait_for_reply(req);
        result = fxp_stat_recv(pktin, req, &attrs);
        sfree(nextoutfname);
        if (!result)
          break;
        i++;
      }
      if (i > 0)
        i--;
    }

    /*
     * Now we're ready to recurse. Starting at ournames[i]
     * and continuing on to the end of the list, we
     * construct a new source and target file name, and
     * call sftp_put_file again.
     */
    for (; i < nnames; i++) {
      char *nextfname, *nextoutfname;
      int ret;

      nextfname = dir_file_cat(fname, ournames[i]);
      nextoutfname = dupcat(outfname, "/", ournames[i], NULL);
      ret = sftp_put_file(nextfname, nextoutfname, recurse, restart);
      restart = FALSE; /* after first partial file, do full */
      sfree(nextoutfname);
      sfree(nextfname);
      if (!ret) {
        for (i = 0; i < nnames; i++) {
          sfree(ournames[i]);
        }
        sfree(ournames);
        return 0;
      }
    }

    /*
     * Done this recursion level. Free everything.
     */
    for (i = 0; i < nnames; i++) {
      sfree(ournames[i]);
    }
    sfree(ournames);

    return 1;
  }

  file = open_existing_file(fname, NULL, NULL, NULL, &permissions);
  if (!file) {
    printf("local: unable to open %s\n", fname);
    return 0;
  }
  attrs.flags = 0;
  PUT_PERMISSIONS(attrs, permissions);
  if (restart) {
    req = fxp_open_send(outfname, SSH_FXF_WRITE, &attrs);
  } else {
    req = fxp_open_send(
        outfname, SSH_FXF_WRITE | SSH_FXF_CREAT | SSH_FXF_TRUNC, &attrs);
  }
  pktin = sftp_wait_for_reply(req);
  fh = fxp_open_recv(pktin, req);

  if (!fh) {
    close_rfile(file);
    printf("%s: open for write: %s\n", outfname, fxp_error());
    return 0;
  }

  if (restart) {
    char decbuf[30];
    struct fxp_attrs attrs;
    int ret;

    req = fxp_fstat_send(fh);
    pktin = sftp_wait_for_reply(req);
    ret = fxp_fstat_recv(pktin, req, &attrs);

    if (!ret) {
      printf("read size of %s: %s\n", outfname, fxp_error());
      err = 1;
      goto cleanup;
    }
    if (!(attrs.flags & SSH_FILEXFER_ATTR_SIZE)) {
      printf("read size of %s: size was not given\n", outfname);
      err = 1;
      goto cleanup;
    }
    offset = attrs.size;
    uint64_decimal(offset, decbuf);
    printf("reput: restarting at file position %s\n", decbuf);

    if (seek_file((WFile *)file, offset, FROM_START) != 0)
      seek_file((WFile *)file, uint64_make(0, 0), FROM_END); /* *shrug* */
  } else {
    offset = uint64_make(0, 0);
  }

  printf("local:%s => remote:%s\n", fname, outfname);

  /*
   * FIXME: we can use FXP_FSTAT here to get the file size, and
   * thus put up a progress bar.
   */
  xfer = xfer_upload_init(fh, offset);
  eof = 0;
  while ((!err && !eof) || !xfer_done(xfer)) {
    char buffer[4096];
    int len, ret;

    while (xfer_upload_ready(xfer) && !err && !eof) {
      len = read_from_file(file, buffer, sizeof(buffer));
      if (len == -1) {
        printf("error while reading local file\n");
        err = 1;
      } else if (len == 0) {
        eof = 1;
      } else {
        xfer_upload_data(xfer, buffer, len);
      }
    }

    if (!xfer_done(xfer)) {
      pktin = sftp_recv();
      ret = xfer_upload_gotpkt(xfer, pktin);
      if (ret <= 0) {
        if (ret == INT_MIN) /* pktin not even freed */
          sfree(pktin);
        if (!err) {
          printf("error while writing: %s\n", fxp_error());
          err = 1;
        }
      }
    }
  }

  xfer_cleanup(xfer);

cleanup:
  req = fxp_close_send(fh);
  pktin = sftp_wait_for_reply(req);
  if (!fxp_close_recv(pktin, req)) {
    if (!err) {
      printf("error while closing: %s", fxp_error());
      err = 1;
    }
  }

  close_rfile(file);

  return (err == 0) ? 1 : 0;
}

/* ----------------------------------------------------------------------
 * A remote wildcard matcher, providing a similar interface to the
 * local one in psftp.h.
 */

typedef struct SftpWildcardMatcher {
  struct fxp_handle *dirh;
  struct fxp_names *names;
  int namepos;
  char *wildcard, *prefix;
} SftpWildcardMatcher;

SftpWildcardMatcher *sftp_begin_wildcard_matching(char *name)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;
  char *wildcard;
  char *unwcdir, *tmpdir, *cdir;
  int len, check;
  SftpWildcardMatcher *swcm;
  struct fxp_handle *dirh;

  /*
   * We don't handle multi-level wildcards; so we expect to find
   * a fully specified directory part, followed by a wildcard
   * after that.
   */
  wildcard = stripslashes(name, 0);

  unwcdir = dupstr(name);
  len = wildcard - name;
  unwcdir[len] = '\0';
  if (len > 0 && unwcdir[len - 1] == '/')
    unwcdir[len - 1] = '\0';
  tmpdir = snewn(1 + len, char);
  check = wc_unescape(tmpdir, unwcdir);
  sfree(tmpdir);

  if (!check) {
    printf("Multiple-level wildcards are not supported\n");
    sfree(unwcdir);
    return NULL;
  }

  cdir = canonify(unwcdir);

  req = fxp_opendir_send(cdir);
  pktin = sftp_wait_for_reply(req);
  dirh = fxp_opendir_recv(pktin, req);

  if (dirh) {
    swcm = snew(SftpWildcardMatcher);
    swcm->dirh = dirh;
    swcm->names = NULL;
    swcm->wildcard = dupstr(wildcard);
    swcm->prefix = unwcdir;
  } else {
    printf("Unable to open %s: %s\n", cdir, fxp_error());
    swcm = NULL;
    sfree(unwcdir);
  }

  sfree(cdir);

  return swcm;
}

char *sftp_wildcard_get_filename(SftpWildcardMatcher *swcm)
{
  struct fxp_name *name;
  struct sftp_packet *pktin;
  struct sftp_request *req;

  while (1) {
    if (swcm->names && swcm->namepos >= swcm->names->nnames) {
      fxp_free_names(swcm->names);
      swcm->names = NULL;
    }

    if (!swcm->names) {
      req = fxp_readdir_send(swcm->dirh);
      pktin = sftp_wait_for_reply(req);
      swcm->names = fxp_readdir_recv(pktin, req);

      if (!swcm->names) {
        if (fxp_error_type() != SSH_FX_EOF)
          printf("%s: reading directory: %s\n", swcm->prefix, fxp_error());
        return NULL;
      } else if (swcm->names->nnames == 0) {
        /*
         * Another failure mode which we treat as EOF is if
         * the server reports success from FXP_READDIR but
         * returns no actual names. This is unusual, since
         * from most servers you'd expect at least "." and
         * "..", but there's nothing forbidding a server from
         * omitting those if it wants to.
         */
        return NULL;
      }

      swcm->namepos = 0;
    }

    assert(swcm->names && swcm->namepos < swcm->names->nnames);

    name = &swcm->names->names[swcm->namepos++];

    if (!strcmp(name->filename, ".") || !strcmp(name->filename, ".."))
      continue; /* expected bad filenames */

    if (!vet_filename(name->filename)) {
      printf("ignoring potentially dangerous server-"
             "supplied filename '%s'\n",
             name->filename);
      continue; /* unexpected bad filename */
    }

    if (!wc_match(swcm->wildcard, name->filename))
      continue; /* doesn't match the wildcard */

    /*
     * We have a working filename. Return it.
     */
    return dupprintf(
        "%s%s%s",
        swcm->prefix,
        (!swcm->prefix[0] || swcm->prefix[strlen(swcm->prefix) - 1] == '/'
             ? ""
             : "/"),
        name->filename);
  }
}

void sftp_finish_wildcard_matching(SftpWildcardMatcher *swcm)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;

  req = fxp_close_send(swcm->dirh);
  pktin = sftp_wait_for_reply(req);
  fxp_close_recv(pktin, req);

  if (swcm->names)
    fxp_free_names(swcm->names);

  sfree(swcm->prefix);
  sfree(swcm->wildcard);

  sfree(swcm);
}

/*
 * General function to match a potential wildcard in a filename
 * argument and iterate over every matching file. Used in several
 * PSFTP commands (rmdir, rm, chmod, mv).
 */
int wildcard_iterate(char *filename, int (*func)(void *, char *), void *ctx)
{
  char *unwcfname, *newname, *cname;
  int is_wc, ret;

  unwcfname = snewn(strlen(filename) + 1, char);
  is_wc = !wc_unescape(unwcfname, filename);

  if (is_wc) {
    SftpWildcardMatcher *swcm = sftp_begin_wildcard_matching(filename);
    int matched = FALSE;
    sfree(unwcfname);

    if (!swcm)
      return 0;

    ret = 1;

    while ((newname = sftp_wildcard_get_filename(swcm)) != NULL) {
      cname = canonify(newname);
      if (!cname) {
        printf("%s: canonify: %s\n", newname, fxp_error());
        ret = 0;
      }
      sfree(newname);
      matched = TRUE;
      ret &= func(ctx, cname);
      sfree(cname);
    }

    if (!matched) {
      /* Politely warn the user that nothing matched. */
      printf("%s: nothing matched\n", filename);
    }

    sftp_finish_wildcard_matching(swcm);
  } else {
    cname = canonify(unwcfname);
    if (!cname) {
      printf("%s: canonify: %s\n", filename, fxp_error());
      ret = 0;
    }
    ret = func(ctx, cname);
    sfree(cname);
    sfree(unwcfname);
  }

  return ret;
}

/*
 * Handy helper function.
 */
int is_wildcard(char *name)
{
  char *unwcfname = snewn(strlen(name) + 1, char);
  int is_wc = !wc_unescape(unwcfname, name);
  sfree(unwcfname);
  return is_wc;
}

/* ----------------------------------------------------------------------
 * Actual sftp commands.
 */
struct sftp_command {
  char **words;
  int nwords, wordssize;
  int (*obey)(struct sftp_command *); /* returns <0 to quit */
};

int sftp_cmd_null(struct sftp_command *cmd)
{
  return 1; /* success */
}

int sftp_cmd_unknown(struct sftp_command *cmd)
{
  printf("psftp: unknown command \"%s\"\n", cmd->words[0]);
  return 0; /* failure */
}

int sftp_cmd_quit(struct sftp_command *cmd)
{
  return -1;
}

int sftp_cmd_close(struct sftp_command *cmd)
{
  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (back != NULL && back->connected(backhandle)) {
    char ch;
    back->special(backhandle, TS_EOF);
    sent_eof = TRUE;
    sftp_recvdata(&ch, 1);
  }
  do_sftp_cleanup();

  return 0;
}

/*
 * List a directory. If no arguments are given, list pwd; otherwise
 * list the directory given in words[1].
 */
int sftp_cmd_ls(struct sftp_command *cmd)
{
  struct fxp_handle *dirh;
  struct fxp_names *names;
  struct fxp_name **ournames;
  int nnames, namesize;
  const char *dir;
  char *cdir, *unwcdir, *wildcard;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  int i;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 2)
    dir = ".";
  else
    dir = cmd->words[1];

  unwcdir = snewn(1 + strlen(dir), char);
  if (wc_unescape(unwcdir, dir)) {
    dir = unwcdir;
    wildcard = NULL;
  } else {
    char *tmpdir;
    int len, check;

    sfree(unwcdir);
    wildcard = stripslashes(dir, 0);
    unwcdir = dupstr(dir);
    len = wildcard - dir;
    unwcdir[len] = '\0';
    if (len > 0 && unwcdir[len - 1] == '/')
      unwcdir[len - 1] = '\0';
    tmpdir = snewn(1 + len, char);
    check = wc_unescape(tmpdir, unwcdir);
    sfree(tmpdir);
    if (!check) {
      printf("Multiple-level wildcards are not supported\n");
      sfree(unwcdir);
      return 0;
    }
    dir = unwcdir;
  }

  cdir = canonify(dir);
  if (!cdir) {
    printf("%s: canonify: %s\n", dir, fxp_error());
    sfree(unwcdir);
    return 0;
  }

  printf("Listing directory %s\n", cdir);

  req = fxp_opendir_send(cdir);
  pktin = sftp_wait_for_reply(req);
  dirh = fxp_opendir_recv(pktin, req);

  if (dirh == NULL) {
    printf("Unable to open %s: %s\n", dir, fxp_error());
    sfree(cdir);
    sfree(unwcdir);
    return 0;
  } else {
    nnames = namesize = 0;
    ournames = NULL;

    while (1) {

      req = fxp_readdir_send(dirh);
      pktin = sftp_wait_for_reply(req);
      names = fxp_readdir_recv(pktin, req);

      if (names == NULL) {
        if (fxp_error_type() == SSH_FX_EOF)
          break;
        printf("Reading directory %s: %s\n", dir, fxp_error());
        break;
      }
      if (names->nnames == 0) {
        fxp_free_names(names);
        break;
      }

      if (nnames + names->nnames >= namesize) {
        namesize += names->nnames + 128;
        ournames = sresize(ournames, namesize, struct fxp_name *);
      }

      for (i = 0; i < names->nnames; i++)
        if (!wildcard || wc_match(wildcard, names->names[i].filename))
          ournames[nnames++] = fxp_dup_name(&names->names[i]);

      fxp_free_names(names);
    }
    req = fxp_close_send(dirh);
    pktin = sftp_wait_for_reply(req);
    fxp_close_recv(pktin, req);

    /*
     * Now we have our filenames. Sort them by actual file
     * name, and then output the longname parts.
     */
    if (nnames > 0)
      qsort(ournames, nnames, sizeof(*ournames), sftp_name_compare);

    /*
     * And print them.
     */
    for (i = 0; i < nnames; i++) {
      printf("%s\n", ournames[i]->longname);
      fxp_free_name(ournames[i]);
    }
    sfree(ournames);
  }

  sfree(cdir);
  sfree(unwcdir);

  return 1;
}

/*
 * Change directories. We do this by canonifying the new name, then
 * trying to OPENDIR it. Only if that succeeds do we set the new pwd.
 */
int sftp_cmd_cd(struct sftp_command *cmd)
{
  struct fxp_handle *dirh;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  char *dir;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 2)
    dir = dupstr(homedir);
  else {
    dir = canonify(cmd->words[1]);
    if (!dir) {
      printf("%s: canonify: %s\n", cmd->words[1], fxp_error());
      return 0;
    }
  }

  req = fxp_opendir_send(dir);
  pktin = sftp_wait_for_reply(req);
  dirh = fxp_opendir_recv(pktin, req);

  if (!dirh) {
    printf("Directory %s: %s\n", dir, fxp_error());
    sfree(dir);
    return 0;
  }

  req = fxp_close_send(dirh);
  pktin = sftp_wait_for_reply(req);
  fxp_close_recv(pktin, req);

  sfree(pwd);
  pwd = dir;
  printf("Remote directory is now %s\n", pwd);

  return 1;
}

/*
 * Print current directory. Easy as pie.
 */
int sftp_cmd_pwd(struct sftp_command *cmd)
{
  if (back == NULL) {
    not_connected();
    return 0;
  }

  printf("Remote directory is %s\n", pwd);
  return 1;
}

/*
 * Get a file and save it at the local end. We have three very
 * similar commands here. The basic one is `get'; `reget' differs
 * in that it checks for the existence of the destination file and
 * starts from where a previous aborted transfer left off; `mget'
 * differs in that it interprets all its arguments as files to
 * transfer (never as a different local name for a remote file) and
 * can handle wildcards.
 */
int sftp_general_get(struct sftp_command *cmd, int restart, int multiple)
{
  char *fname, *unwcfname, *origfname, *origwfname, *outfname;
  int i, ret;
  int recurse = FALSE;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  i = 1;
  while (i < cmd->nwords && cmd->words[i][0] == '-') {
    if (!strcmp(cmd->words[i], "--")) {
      /* finish processing options */
      i++;
      break;
    } else if (!strcmp(cmd->words[i], "-r")) {
      recurse = TRUE;
    } else {
      printf("%s: unrecognised option '%s'\n", cmd->words[0], cmd->words[i]);
      return 0;
    }
    i++;
  }

  if (i >= cmd->nwords) {
    printf("%s: expects a filename\n", cmd->words[0]);
    return 0;
  }

  ret = 1;
  do {
    SftpWildcardMatcher *swcm;

    origfname = cmd->words[i++];
    unwcfname = snewn(strlen(origfname) + 1, char);

    if (multiple && !wc_unescape(unwcfname, origfname)) {
      swcm = sftp_begin_wildcard_matching(origfname);
      if (!swcm) {
        sfree(unwcfname);
        continue;
      }
      origwfname = sftp_wildcard_get_filename(swcm);
      if (!origwfname) {
        /* Politely warn the user that nothing matched. */
        printf("%s: nothing matched\n", origfname);
        sftp_finish_wildcard_matching(swcm);
        sfree(unwcfname);
        continue;
      }
    } else {
      origwfname = origfname;
      swcm = NULL;
    }

    while (origwfname) {
      fname = canonify(origwfname);

      if (!fname) {
        sftp_finish_wildcard_matching(swcm);
        printf("%s: canonify: %s\n", origwfname, fxp_error());
        sfree(origwfname);
        sfree(unwcfname);
        return 0;
      }

      if (!multiple && i < cmd->nwords)
        outfname = cmd->words[i++];
      else
        outfname = stripslashes(origwfname, 0);

      ret = sftp_get_file(fname, outfname, recurse, restart);

      sfree(fname);

      if (swcm) {
        sfree(origwfname);
        origwfname = sftp_wildcard_get_filename(swcm);
      } else {
        origwfname = NULL;
      }
    }
    sfree(unwcfname);
    if (swcm)
      sftp_finish_wildcard_matching(swcm);
    if (!ret)
      return ret;

  } while (multiple && i < cmd->nwords);

  return ret;
}
int sftp_cmd_get(struct sftp_command *cmd)
{
  return sftp_general_get(cmd, 0, 0);
}
int sftp_cmd_mget(struct sftp_command *cmd)
{
  return sftp_general_get(cmd, 0, 1);
}
int sftp_cmd_reget(struct sftp_command *cmd)
{
  return sftp_general_get(cmd, 1, 0);
}

/*
 * Send a file and store it at the remote end. We have three very
 * similar commands here. The basic one is `put'; `reput' differs
 * in that it checks for the existence of the destination file and
 * starts from where a previous aborted transfer left off; `mput'
 * differs in that it interprets all its arguments as files to
 * transfer (never as a different remote name for a local file) and
 * can handle wildcards.
 */
int sftp_general_put(struct sftp_command *cmd, int restart, int multiple)
{
  char *fname, *wfname, *origoutfname, *outfname;
  int i, ret;
  int recurse = FALSE;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  i = 1;
  while (i < cmd->nwords && cmd->words[i][0] == '-') {
    if (!strcmp(cmd->words[i], "--")) {
      /* finish processing options */
      i++;
      break;
    } else if (!strcmp(cmd->words[i], "-r")) {
      recurse = TRUE;
    } else {
      printf("%s: unrecognised option '%s'\n", cmd->words[0], cmd->words[i]);
      return 0;
    }
    i++;
  }

  if (i >= cmd->nwords) {
    printf("%s: expects a filename\n", cmd->words[0]);
    return 0;
  }

  ret = 1;
  do {
    WildcardMatcher *wcm;
    fname = cmd->words[i++];

    if (multiple && test_wildcard(fname, FALSE) == WCTYPE_WILDCARD) {
      wcm = begin_wildcard_matching(fname);
      wfname = wildcard_get_filename(wcm);
      if (!wfname) {
        /* Politely warn the user that nothing matched. */
        printf("%s: nothing matched\n", fname);
        finish_wildcard_matching(wcm);
        continue;
      }
    } else {
      wfname = fname;
      wcm = NULL;
    }

    while (wfname) {
      if (!multiple && i < cmd->nwords)
        origoutfname = cmd->words[i++];
      else
        origoutfname = stripslashes(wfname, 1);

      outfname = canonify(origoutfname);
      if (!outfname) {
        printf("%s: canonify: %s\n", origoutfname, fxp_error());
        if (wcm) {
          sfree(wfname);
          finish_wildcard_matching(wcm);
        }
        return 0;
      }
      ret = sftp_put_file(wfname, outfname, recurse, restart);
      sfree(outfname);

      if (wcm) {
        sfree(wfname);
        wfname = wildcard_get_filename(wcm);
      } else {
        wfname = NULL;
      }
    }

    if (wcm)
      finish_wildcard_matching(wcm);

    if (!ret)
      return ret;

  } while (multiple && i < cmd->nwords);

  return ret;
}
int sftp_cmd_put(struct sftp_command *cmd)
{
  return sftp_general_put(cmd, 0, 0);
}
int sftp_cmd_mput(struct sftp_command *cmd)
{
  return sftp_general_put(cmd, 0, 1);
}
int sftp_cmd_reput(struct sftp_command *cmd)
{
  return sftp_general_put(cmd, 1, 0);
}

int sftp_cmd_mkdir(struct sftp_command *cmd)
{
  char *dir;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  int result;
  int i, ret;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 2) {
    printf("mkdir: expects a directory\n");
    return 0;
  }

  ret = 1;
  for (i = 1; i < cmd->nwords; i++) {
    dir = canonify(cmd->words[i]);
    if (!dir) {
      printf("%s: canonify: %s\n", cmd->words[i], fxp_error());
      return 0;
    }

    req = fxp_mkdir_send(dir);
    pktin = sftp_wait_for_reply(req);
    result = fxp_mkdir_recv(pktin, req);

    if (!result) {
      printf("mkdir %s: %s\n", dir, fxp_error());
      ret = 0;
    } else
      printf("mkdir %s: OK\n", dir);

    sfree(dir);
  }

  return ret;
}

static int sftp_action_rmdir(void *vctx, char *dir)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;
  int result;

  req = fxp_rmdir_send(dir);
  pktin = sftp_wait_for_reply(req);
  result = fxp_rmdir_recv(pktin, req);

  if (!result) {
    printf("rmdir %s: %s\n", dir, fxp_error());
    return 0;
  }

  printf("rmdir %s: OK\n", dir);

  return 1;
}

int sftp_cmd_rmdir(struct sftp_command *cmd)
{
  int i, ret;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 2) {
    printf("rmdir: expects a directory\n");
    return 0;
  }

  ret = 1;
  for (i = 1; i < cmd->nwords; i++)
    ret &= wildcard_iterate(cmd->words[i], sftp_action_rmdir, NULL);

  return ret;
}

static int sftp_action_rm(void *vctx, char *fname)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;
  int result;

  req = fxp_remove_send(fname);
  pktin = sftp_wait_for_reply(req);
  result = fxp_remove_recv(pktin, req);

  if (!result) {
    printf("rm %s: %s\n", fname, fxp_error());
    return 0;
  }

  printf("rm %s: OK\n", fname);

  return 1;
}

int sftp_cmd_rm(struct sftp_command *cmd)
{
  int i, ret;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 2) {
    printf("rm: expects a filename\n");
    return 0;
  }

  ret = 1;
  for (i = 1; i < cmd->nwords; i++)
    ret &= wildcard_iterate(cmd->words[i], sftp_action_rm, NULL);

  return ret;
}

static int check_is_dir(char *dstfname)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;
  struct fxp_attrs attrs;
  int result;

  req = fxp_stat_send(dstfname);
  pktin = sftp_wait_for_reply(req);
  result = fxp_stat_recv(pktin, req, &attrs);

  if (result && (attrs.flags & SSH_FILEXFER_ATTR_PERMISSIONS) &&
      (attrs.permissions & 0040000))
    return TRUE;
  else
    return FALSE;
}

struct sftp_context_mv {
  char *dstfname;
  int dest_is_dir;
};

static int sftp_action_mv(void *vctx, char *srcfname)
{
  struct sftp_context_mv *ctx = (struct sftp_context_mv *)vctx;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  const char *error;
  char *finalfname, *newcanon = NULL;
  int ret, result;

  if (ctx->dest_is_dir) {
    char *p;
    char *newname;

    p = srcfname + strlen(srcfname);
    while (p > srcfname && p[-1] != '/')
      p--;
    newname = dupcat(ctx->dstfname, "/", p, NULL);
    newcanon = canonify(newname);
    if (!newcanon) {
      printf("%s: canonify: %s\n", newname, fxp_error());
      sfree(newname);
      return 0;
    }
    sfree(newname);

    finalfname = newcanon;
  } else {
    finalfname = ctx->dstfname;
  }

  req = fxp_rename_send(srcfname, finalfname);
  pktin = sftp_wait_for_reply(req);
  result = fxp_rename_recv(pktin, req);

  error = result ? NULL : fxp_error();

  if (error) {
    printf("mv %s %s: %s\n", srcfname, finalfname, error);
    ret = 0;
  } else {
    printf("%s -> %s\n", srcfname, finalfname);
    ret = 1;
  }

  sfree(newcanon);
  return ret;
}

int sftp_cmd_mv(struct sftp_command *cmd)
{
  struct sftp_context_mv actx, *ctx = &actx;
  int i, ret;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 3) {
    printf("mv: expects two filenames\n");
    return 0;
  }

  ctx->dstfname = canonify(cmd->words[cmd->nwords - 1]);
  if (!ctx->dstfname) {
    printf("%s: canonify: %s\n", ctx->dstfname, fxp_error());
    return 0;
  }

  /*
   * If there's more than one source argument, or one source
   * argument which is a wildcard, we _require_ that the
   * destination is a directory.
   */
  ctx->dest_is_dir = check_is_dir(ctx->dstfname);
  if ((cmd->nwords > 3 || is_wildcard(cmd->words[1])) && !ctx->dest_is_dir) {
    printf("mv: multiple or wildcard arguments require the destination"
           " to be a directory\n");
    sfree(ctx->dstfname);
    return 0;
  }

  /*
   * Now iterate over the source arguments.
   */
  ret = 1;
  for (i = 1; i < cmd->nwords - 1; i++)
    ret &= wildcard_iterate(cmd->words[i], sftp_action_mv, ctx);

  sfree(ctx->dstfname);
  return ret;
}

struct sftp_context_chmod {
  unsigned attrs_clr, attrs_xor;
};

static int sftp_action_chmod(void *vctx, char *fname)
{
  struct fxp_attrs attrs;
  struct sftp_packet *pktin;
  struct sftp_request *req;
  int result;
  unsigned oldperms, newperms;
  struct sftp_context_chmod *ctx = (struct sftp_context_chmod *)vctx;

  req = fxp_stat_send(fname);
  pktin = sftp_wait_for_reply(req);
  result = fxp_stat_recv(pktin, req, &attrs);

  if (!result || !(attrs.flags & SSH_FILEXFER_ATTR_PERMISSIONS)) {
    printf("get attrs for %s: %s\n",
           fname,
           result ? "file permissions not provided" : fxp_error());
    return 0;
  }

  attrs.flags = SSH_FILEXFER_ATTR_PERMISSIONS; /* perms _only_ */
  oldperms = attrs.permissions & 07777;
  attrs.permissions &= ~ctx->attrs_clr;
  attrs.permissions ^= ctx->attrs_xor;
  newperms = attrs.permissions & 07777;

  if (oldperms == newperms)
    return 1; /* no need to do anything! */

  req = fxp_setstat_send(fname, attrs);
  pktin = sftp_wait_for_reply(req);
  result = fxp_setstat_recv(pktin, req);

  if (!result) {
    printf("set attrs for %s: %s\n", fname, fxp_error());
    return 0;
  }

  printf("%s: %04o -> %04o\n", fname, oldperms, newperms);

  return 1;
}

int sftp_cmd_chmod(struct sftp_command *cmd)
{
  char *mode;
  int i, ret;
  struct sftp_context_chmod actx, *ctx = &actx;

  if (back == NULL) {
    not_connected();
    return 0;
  }

  if (cmd->nwords < 3) {
    printf("chmod: expects a mode specifier and a filename\n");
    return 0;
  }

  /*
   * Attempt to parse the mode specifier in cmd->words[1]. We
   * don't support the full horror of Unix chmod; instead we
   * support a much simpler syntax in which the user can either
   * specify an octal number, or a comma-separated sequence of
   * [ugoa]*[-+=][rwxst]+. (The initial [ugoa] sequence may
   * _only_ be omitted if the only attribute mentioned is t,
   * since all others require a user/group/other specification.
   * Additionally, the s attribute may not be specified for any
   * [ugoa] specifications other than exactly u or exactly g.
   */
  ctx->attrs_clr = ctx->attrs_xor = 0;
  mode = cmd->words[1];
  if (mode[0] >= '0' && mode[0] <= '9') {
    if (mode[strspn(mode, "01234567")]) {
      printf("chmod: numeric file modes should"
             " contain digits 0-7 only\n");
      return 0;
    }
    ctx->attrs_clr = 07777;
    sscanf(mode, "%o", &ctx->attrs_xor);
    ctx->attrs_xor &= ctx->attrs_clr;
  } else {
    while (*mode) {
      char *modebegin = mode;
      unsigned subset, perms;
      int action;

      subset = 0;
      while (*mode && *mode != ',' && *mode != '+' && *mode != '-' &&
             *mode != '=') {
        switch (*mode) {
        case 'u':
          subset |= 04700;
          break; /* setuid, user perms */
        case 'g':
          subset |= 02070;
          break; /* setgid, group perms */
        case 'o':
          subset |= 00007;
          break; /* just other perms */
        case 'a':
          subset |= 06777;
          break; /* all of the above */
        default:
          printf("chmod: file mode '%.*s' contains unrecognised"
                 " user/group/other specifier '%c'\n",
                 (int)strcspn(modebegin, ","),
                 modebegin,
                 *mode);
          return 0;
        }
        mode++;
      }
      if (!*mode || *mode == ',') {
        printf("chmod: file mode '%.*s' is incomplete\n",
               (int)strcspn(modebegin, ","),
               modebegin);
        return 0;
      }
      action = *mode++;
      if (!*mode || *mode == ',') {
        printf("chmod: file mode '%.*s' is incomplete\n",
               (int)strcspn(modebegin, ","),
               modebegin);
        return 0;
      }
      perms = 0;
      while (*mode && *mode != ',') {
        switch (*mode) {
        case 'r':
          perms |= 00444;
          break;
        case 'w':
          perms |= 00222;
          break;
        case 'x':
          perms |= 00111;
          break;
        case 't':
          perms |= 01000;
          subset |= 01000;
          break;
        case 's':
          if ((subset & 06777) != 04700 && (subset & 06777) != 02070) {
            printf("chmod: file mode '%.*s': set[ug]id bit should"
                   " be used with exactly one of u or g only\n",
                   (int)strcspn(modebegin, ","),
                   modebegin);
            return 0;
          }
          perms |= 06000;
          break;
        default:
          printf("chmod: file mode '%.*s' contains unrecognised"
                 " permission specifier '%c'\n",
                 (int)strcspn(modebegin, ","),
                 modebegin,
                 *mode);
          return 0;
        }
        mode++;
      }
      if (!(subset & 06777) && (perms & ~subset)) {
        printf("chmod: file mode '%.*s' contains no user/group/other"
               " specifier and permissions other than 't' \n",
               (int)strcspn(modebegin, ","),
               modebegin);
        return 0;
      }
      perms &= subset;
      switch (action) {
      case '+':
        ctx->attrs_clr |= perms;
        ctx->attrs_xor |= perms;
        break;
      case '-':
        ctx->attrs_clr |= perms;
        ctx->attrs_xor &= ~perms;
        break;
      case '=':
        ctx->attrs_clr |= subset;
        ctx->attrs_xor |= perms;
        break;
      }
      if (*mode)
        mode++; /* eat comma */
    }
  }

  ret = 1;
  for (i = 2; i < cmd->nwords; i++)
    ret &= wildcard_iterate(cmd->words[i], sftp_action_chmod, ctx);

  return ret;
}

static int sftp_cmd_open(struct sftp_command *cmd)
{
  int portnumber;

  if (back != NULL) {
    printf("psftp: already connected\n");
    return 0;
  }

  if (cmd->nwords < 2) {
    printf("open: expects a host name\n");
    return 0;
  }

  if (cmd->nwords > 2) {
    portnumber = atoi(cmd->words[2]);
    if (portnumber == 0) {
      printf("open: invalid port number\n");
      return 0;
    }
  } else
    portnumber = 0;

  if (psftp_connect(cmd->words[1], NULL, portnumber)) {
    back = NULL; /* connection is already closed */
    return -1;   /* this is fatal */
  }
  do_sftp_init();
  return 1;
}

static int sftp_cmd_lcd(struct sftp_command *cmd)
{
  char *currdir, *errmsg;

  if (cmd->nwords < 2) {
    printf("lcd: expects a local directory name\n");
    return 0;
  }

  errmsg = psftp_lcd(cmd->words[1]);
  if (errmsg) {
    printf("lcd: unable to change directory: %s\n", errmsg);
    sfree(errmsg);
    return 0;
  }

  currdir = psftp_getcwd();
  printf("New local directory is %s\n", currdir);
  sfree(currdir);

  return 1;
}

static int sftp_cmd_lpwd(struct sftp_command *cmd)
{
  char *currdir;

  currdir = psftp_getcwd();
  printf("Current local directory is %s\n", currdir);
  sfree(currdir);

  return 1;
}

static int sftp_cmd_pling(struct sftp_command *cmd)
{
  int exitcode;

  exitcode = system(cmd->words[1]);
  return (exitcode == 0);
}

static int sftp_cmd_help(struct sftp_command *cmd);

static struct sftp_cmd_lookup {
  const char *name;
  /*
   * For help purposes, there are two kinds of command:
   *
   *  - primary commands, in which `longhelp' is non-NULL. In
   *    this case `shorthelp' is descriptive text, and `longhelp'
   *    is longer descriptive text intended to be printed after
   *    the command name.
   *
   *  - alias commands, in which `longhelp' is NULL. In this case
   *    `shorthelp' is the name of a primary command, which
   *    contains the help that should double up for this command.
   */
  int listed; /* do we list this in primary help? */
  const char *shorthelp;
  const char *longhelp;
  int (*obey)(struct sftp_command *);
} sftp_lookup[] = {
    /*
     * List of sftp commands. This is binary-searched so it MUST be
     * in ASCII order.
     */
    {"!",
     TRUE,
     "run a local command",
     "<command>\n"
     /* FIXME: this example is crap for non-Windows. */
     "  Runs a local command. For example, \"!del myfile\".\n",
     sftp_cmd_pling},
    {"bye",
     TRUE,
     "finish your SFTP session",
     "\n"
     "  Terminates your SFTP session and quits the PSFTP program.\n",
     sftp_cmd_quit},
    {"cd",
     TRUE,
     "change your remote working directory",
     " [ <new working directory> ]\n"
     "  Change the remote working directory for your SFTP session.\n"
     "  If a new working directory is not supplied, you will be\n"
     "  returned to your home directory.\n",
     sftp_cmd_cd},
    {"chmod",
     TRUE,
     "change file permissions and modes",
     " <modes> <filename-or-wildcard> [ <filename-or-wildcard>... ]\n"
     "  Change the file permissions on one or more remote files or\n"
     "  directories.\n"
     "  <modes> can be any octal Unix permission specifier.\n"
     "  Alternatively, <modes> can include the following modifiers:\n"
     "    u+r     make file readable by owning user\n"
     "    u+w     make file writable by owning user\n"
     "    u+x     make file executable by owning user\n"
     "    u-r     make file not readable by owning user\n"
     "    [also u-w, u-x]\n"
     "    g+r     make file readable by members of owning group\n"
     "    [also g+w, g+x, g-r, g-w, g-x]\n"
     "    o+r     make file readable by all other users\n"
     "    [also o+w, o+x, o-r, o-w, o-x]\n"
     "    a+r     make file readable by absolutely everybody\n"
     "    [also a+w, a+x, a-r, a-w, a-x]\n"
     "    u+s     enable the Unix set-user-ID bit\n"
     "    u-s     disable the Unix set-user-ID bit\n"
     "    g+s     enable the Unix set-group-ID bit\n"
     "    g-s     disable the Unix set-group-ID bit\n"
     "    +t      enable the Unix \"sticky bit\"\n"
     "  You can give more than one modifier for the same user (\"g-rwx\"), "
     "and\n"
     "  more than one user for the same modifier (\"ug+w\"). You can\n"
     "  use commas to separate different modifiers (\"u+rwx,g+s\").\n",
     sftp_cmd_chmod},
    {"close",
     TRUE,
     "finish your SFTP session but do not quit PSFTP",
     "\n"
     "  Terminates your SFTP session, but does not quit the PSFTP\n"
     "  program. You can then use \"open\" to start another SFTP\n"
     "  session, to the same server or to a different one.\n",
     sftp_cmd_close},
    {"del",
     TRUE,
     "delete files on the remote server",
     " <filename-or-wildcard> [ <filename-or-wildcard>... ]\n"
     "  Delete a file or files from the server.\n",
     sftp_cmd_rm},
    {"delete", FALSE, "del", NULL, sftp_cmd_rm},
    {"dir",
     TRUE,
     "list remote files",
     " [ <directory-name> ]/[ <wildcard> ]\n"
     "  List the contents of a specified directory on the server.\n"
     "  If <directory-name> is not given, the current working directory\n"
     "  is assumed.\n"
     "  If <wildcard> is given, it is treated as a set of files to\n"
     "  list; otherwise, all files are listed.\n",
     sftp_cmd_ls},
    {"exit", TRUE, "bye", NULL, sftp_cmd_quit},
    {"get",
     TRUE,
     "download a file from the server to your local machine",
     " [ -r ] [ -- ] <filename> [ <local-filename> ]\n"
     "  Downloads a file on the server and stores it locally under\n"
     "  the same name, or under a different one if you supply the\n"
     "  argument <local-filename>.\n"
     "  If -r specified, recursively fetch a directory.\n",
     sftp_cmd_get},
    {"help",
     TRUE,
     "give help",
     " [ <command> [ <command> ... ] ]\n"
     "  Give general help if no commands are specified.\n"
     "  If one or more commands are specified, give specific help on\n"
     "  those particular commands.\n",
     sftp_cmd_help},
    {"lcd",
     TRUE,
     "change local working directory",
     " <local-directory-name>\n"
     "  Change the local working directory of the PSFTP program (the\n"
     "  default location where the \"get\" command will save files).\n",
     sftp_cmd_lcd},
    {"lpwd",
     TRUE,
     "print local working directory",
     "\n"
     "  Print the local working directory of the PSFTP program (the\n"
     "  default location where the \"get\" command will save files).\n",
     sftp_cmd_lpwd},
    {"ls", TRUE, "dir", NULL, sftp_cmd_ls},
    {"mget",
     TRUE,
     "download multiple files at once",
     " [ -r ] [ -- ] <filename-or-wildcard> [ <filename-or-wildcard>... ]\n"
     "  Downloads many files from the server, storing each one under\n"
     "  the same name it has on the server side. You can use wildcards\n"
     "  such as \"*.c\" to specify lots of files at once.\n"
     "  If -r specified, recursively fetch files and directories.\n",
     sftp_cmd_mget},
    {"mkdir",
     TRUE,
     "create directories on the remote server",
     " <directory-name> [ <directory-name>... ]\n"
     "  Creates directories with the given names on the server.\n",
     sftp_cmd_mkdir},
    {"mput",
     TRUE,
     "upload multiple files at once",
     " [ -r ] [ -- ] <filename-or-wildcard> [ <filename-or-wildcard>... ]\n"
     "  Uploads many files to the server, storing each one under the\n"
     "  same name it has on the client side. You can use wildcards\n"
     "  such as \"*.c\" to specify lots of files at once.\n"
     "  If -r specified, recursively store files and directories.\n",
     sftp_cmd_mput},
    {"mv",
     TRUE,
     "move or rename file(s) on the remote server",
     " <source> [ <source>... ] <destination>\n"
     "  Moves or renames <source>(s) on the server to <destination>,\n"
     "  also on the server.\n"
     "  If <destination> specifies an existing directory, then <source>\n"
     "  may be a wildcard, and multiple <source>s may be given; all\n"
     "  source files are moved into <destination>.\n"
     "  Otherwise, <source> must specify a single file, which is moved\n"
     "  or renamed so that it is accessible under the name <destination>.\n",
     sftp_cmd_mv},
    {"open",
     TRUE,
     "connect to a host",
     " [<user>@]<hostname> [<port>]\n"
     "  Establishes an SFTP connection to a given host. Only usable\n"
     "  when you are not already connected to a server.\n",
     sftp_cmd_open},
    {"put",
     TRUE,
     "upload a file from your local machine to the server",
     " [ -r ] [ -- ] <filename> [ <remote-filename> ]\n"
     "  Uploads a file to the server and stores it there under\n"
     "  the same name, or under a different one if you supply the\n"
     "  argument <remote-filename>.\n"
     "  If -r specified, recursively store a directory.\n",
     sftp_cmd_put},
    {"pwd",
     TRUE,
     "print your remote working directory",
     "\n"
     "  Print the current remote working directory for your SFTP session.\n",
     sftp_cmd_pwd},
    {"quit", TRUE, "bye", NULL, sftp_cmd_quit},
    {"reget",
     TRUE,
     "continue downloading files",
     " [ -r ] [ -- ] <filename> [ <local-filename> ]\n"
     "  Works exactly like the \"get\" command, but the local file\n"
     "  must already exist. The download will begin at the end of the\n"
     "  file. This is for resuming a download that was interrupted.\n"
     "  If -r specified, resume interrupted \"get -r\".\n",
     sftp_cmd_reget},
    {"ren", TRUE, "mv", NULL, sftp_cmd_mv},
    {"rename", FALSE, "mv", NULL, sftp_cmd_mv},
    {"reput",
     TRUE,
     "continue uploading files",
     " [ -r ] [ -- ] <filename> [ <remote-filename> ]\n"
     "  Works exactly like the \"put\" command, but the remote file\n"
     "  must already exist. The upload will begin at the end of the\n"
     "  file. This is for resuming an upload that was interrupted.\n"
     "  If -r specified, resume interrupted \"put -r\".\n",
     sftp_cmd_reput},
    {"rm", TRUE, "del", NULL, sftp_cmd_rm},
    {"rmdir",
     TRUE,
     "remove directories on the remote server",
     " <directory-name> [ <directory-name>... ]\n"
     "  Removes the directory with the given name on the server.\n"
     "  The directory will not be removed unless it is empty.\n"
     "  Wildcards may be used to specify multiple directories.\n",
     sftp_cmd_rmdir}};

const struct sftp_cmd_lookup *lookup_command(const char *name)
{
  int i, j, k, cmp;

  i = -1;
  j = sizeof(sftp_lookup) / sizeof(*sftp_lookup);
  while (j - i > 1) {
    k = (j + i) / 2;
    cmp = strcmp(name, sftp_lookup[k].name);
    if (cmp < 0)
      j = k;
    else if (cmp > 0)
      i = k;
    else {
      return &sftp_lookup[k];
    }
  }
  return NULL;
}

static int sftp_cmd_help(struct sftp_command *cmd)
{
  int i;
  if (cmd->nwords == 1) {
    /*
     * Give short help on each command.
     */
    int maxlen;
    maxlen = 0;
    for (i = 0; i < sizeof(sftp_lookup) / sizeof(*sftp_lookup); i++) {
      int len;
      if (!sftp_lookup[i].listed)
        continue;
      len = strlen(sftp_lookup[i].name);
      if (maxlen < len)
        maxlen = len;
    }
    for (i = 0; i < sizeof(sftp_lookup) / sizeof(*sftp_lookup); i++) {
      const struct sftp_cmd_lookup *lookup;
      if (!sftp_lookup[i].listed)
        continue;
      lookup = &sftp_lookup[i];
      printf("%-*s", maxlen + 2, lookup->name);
      if (lookup->longhelp == NULL)
        lookup = lookup_command(lookup->shorthelp);
      printf("%s\n", lookup->shorthelp);
    }
  } else {
    /*
     * Give long help on specific commands.
     */
    for (i = 1; i < cmd->nwords; i++) {
      const struct sftp_cmd_lookup *lookup;
      lookup = lookup_command(cmd->words[i]);
      if (!lookup) {
        printf("help: %s: command not found\n", cmd->words[i]);
      } else {
        printf("%s", lookup->name);
        if (lookup->longhelp == NULL)
          lookup = lookup_command(lookup->shorthelp);
        printf("%s", lookup->longhelp);
      }
    }
  }
  return 1;
}

/* ----------------------------------------------------------------------
 * Command line reading and parsing.
 */
struct sftp_command *sftp_getcmd(FILE *fp, int mode, int modeflags)
{
  char *line;
  struct sftp_command *cmd;
  char *p, *q, *r;
  int quoting;

  cmd = snew(struct sftp_command);
  cmd->words = NULL;
  cmd->nwords = 0;
  cmd->wordssize = 0;

  line = NULL;

  if (fp) {
    if (modeflags & 1)
      printf("psftp> ");
    line = fgetline(fp);
  } else {
    line = ssh_sftp_get_cmdline("psftp> ", back == NULL);
  }

  if (!line || !*line) {
    cmd->obey = sftp_cmd_quit;
    if ((mode == 0) || (modeflags & 1))
      printf("quit\n");
    sfree(line);
    return cmd; /* eof */
  }

  line[strcspn(line, "\r\n")] = '\0';

  if (modeflags & 1) {
    printf("%s\n", line);
  }

  p = line;
  while (*p && (*p == ' ' || *p == '\t'))
    p++;

  if (*p == '!') {
    /*
     * Special case: the ! command. This is always parsed as
     * exactly two words: one containing the !, and the second
     * containing everything else on the line.
     */
    cmd->nwords = cmd->wordssize = 2;
    cmd->words = sresize(cmd->words, cmd->wordssize, char *);
    cmd->words[0] = dupstr("!");
    cmd->words[1] = dupstr(p + 1);
  } else if (*p == '#') {
    /*
     * Special case: comment. Entire line is ignored.
     */
    cmd->nwords = cmd->wordssize = 0;
  } else {

    /*
     * Parse the command line into words. The syntax is:
     *  - double quotes are removed, but cause spaces within to be
     *    treated as non-separating.
     *  - a double-doublequote pair is a literal double quote, inside
     *    _or_ outside quotes. Like this:
     *
     *      firstword "second word" "this has ""quotes"" in" and""this""
     *
     * becomes
     *
     *      >firstword<
     *      >second word<
     *      >this has "quotes" in<
     *      >and"this"<
     */
    while (1) {
      /* skip whitespace */
      while (*p && (*p == ' ' || *p == '\t'))
        p++;
      /* terminate loop */
      if (!*p)
        break;
      /* mark start of word */
      q = r = p; /* q sits at start, r writes word */
      quoting = 0;
      while (*p) {
        if (!quoting && (*p == ' ' || *p == '\t'))
          break; /* reached end of word */
        else if (*p == '"' && p[1] == '"')
          p += 2, *r++ = '"'; /* a literal quote */
        else if (*p == '"')
          p++, quoting = !quoting;
        else
          *r++ = *p++;
      }
      if (*p)
        p++; /* skip over the whitespace */
      *r = '\0';
      if (cmd->nwords >= cmd->wordssize) {
        cmd->wordssize = cmd->nwords + 16;
        cmd->words = sresize(cmd->words, cmd->wordssize, char *);
      }
      cmd->words[cmd->nwords++] = dupstr(q);
    }
  }

  sfree(line);

  /*
   * Now parse the first word and assign a function.
   */

  if (cmd->nwords == 0)
    cmd->obey = sftp_cmd_null;
  else {
    const struct sftp_cmd_lookup *lookup;
    lookup = lookup_command(cmd->words[0]);
    if (!lookup)
      cmd->obey = sftp_cmd_unknown;
    else
      cmd->obey = lookup->obey;
  }

  return cmd;
}

static int do_sftp_init(void)
{
  struct sftp_packet *pktin;
  struct sftp_request *req;

  /*
   * Do protocol initialisation.
   */
  if (!fxp_init()) {
    fprintf(stderr, "Fatal: unable to initialise SFTP: %s\n", fxp_error());
    return 1; /* failure */
  }

  /*
   * Find out where our home directory is.
   */
  req = fxp_realpath_send(".");
  pktin = sftp_wait_for_reply(req);
  homedir = fxp_realpath_recv(pktin, req);

  if (!homedir) {
    fprintf(
        stderr, "Warning: failed to resolve home directory: %s\n", fxp_error());
    homedir = dupstr(".");
  } else {
    printf("Remote working directory is %s\n", homedir);
  }
  pwd = dupstr(homedir);
  return 0;
}

void do_sftp_cleanup()
{
  char ch;
  if (back) {
    back->special(backhandle, TS_EOF);
    sent_eof = TRUE;
    sftp_recvdata(&ch, 1);
    back->free(backhandle);
    sftp_cleanup_request();
    back = NULL;
    backhandle = NULL;
  }
  if (pwd) {
    sfree(pwd);
    pwd = NULL;
  }
  if (homedir) {
    sfree(homedir);
    homedir = NULL;
  }
}

int do_sftp(int mode, int modeflags, char *batchfile)
{
  FILE *fp;
  int ret;

  /*
   * Batch mode?
   */
  if (mode == 0) {

    /* ------------------------------------------------------------------
     * Now we're ready to do Real Stuff.
     */
    while (1) {
      struct sftp_command *cmd;
      cmd = sftp_getcmd(NULL, 0, 0);
      if (!cmd)
        break;
      ret = cmd->obey(cmd);
      if (cmd->words) {
        int i;
        for (i = 0; i < cmd->nwords; i++)
          sfree(cmd->words[i]);
        sfree(cmd->words);
      }
      sfree(cmd);
      if (ret < 0)
        break;
    }
  } else {
    fp = fopen(batchfile, "r");
    if (!fp) {
      printf("Fatal: unable to open %s\n", batchfile);
      return 1;
    }
    ret = 0;
    while (1) {
      struct sftp_command *cmd;
      cmd = sftp_getcmd(fp, mode, modeflags);
      if (!cmd)
        break;
      ret = cmd->obey(cmd);
      if (ret < 0)
        break;
      if (ret == 0) {
        if (!(modeflags & 2))
          break;
      }
    }
    fclose(fp);
    /*
     * In batch mode, and if exit on command failure is enabled,
     * any command failure causes the whole of PSFTP to fail.
     */
    if (ret == 0 && !(modeflags & 2))
      return 2;
  }
  return 0;
}

/* ----------------------------------------------------------------------
 * Dirty bits: integration with PuTTY.
 */

static int verbose = 0;

/*
 *  Print an error message and perform a fatal exit.
 */
void fatalbox(const char *fmt, ...)
{
  char *str, *str2;
  va_list ap;
  va_start(ap, fmt);
  str = dupvprintf(fmt, ap);
  str2 = dupcat("Fatal: ", str, "\n", NULL);
  sfree(str);
  va_end(ap);
  fputs(str2, stderr);
  sfree(str2);

  cleanup_exit(1);
}
void modalfatalbox(const char *fmt, ...)
{
  char *str, *str2;
  va_list ap;
  va_start(ap, fmt);
  str = dupvprintf(fmt, ap);
  str2 = dupcat("Fatal: ", str, "\n", NULL);
  sfree(str);
  va_end(ap);
  fputs(str2, stderr);
  sfree(str2);

  cleanup_exit(1);
}
void nonfatal(const char *fmt, ...)
{
  char *str, *str2;
  va_list ap;
  va_start(ap, fmt);
  str = dupvprintf(fmt, ap);
  str2 = dupcat("Error: ", str, "\n", NULL);
  sfree(str);
  va_end(ap);
  fputs(str2, stderr);
  sfree(str2);
}
void connection_fatal(void *frontend, const char *fmt, ...)
{
  char *str, *str2;
  va_list ap;
  va_start(ap, fmt);
  str = dupvprintf(fmt, ap);
  str2 = dupcat("Fatal: ", str, "\n", NULL);
  sfree(str);
  va_end(ap);
  fputs(str2, stderr);
  sfree(str2);

  cleanup_exit(1);
}

void ldisc_echoedit_update(void *handle)
{
}

/*
 * In psftp, all agent requests should be synchronous, so this is a
 * never-called stub.
 */
void agent_schedule_callback(void (*callback)(void *, void *, int),
                             void *callback_ctx,
                             void *data,
                             int len)
{
  assert(!"We shouldn't be here");
}

/*
 * Receive a block of data from the SSH link. Block until all data
 * is available.
 *
 * To do this, we repeatedly call the SSH protocol module, with our
 * own trap in from_backend() to catch the data that comes back. We
 * do this until we have enough data.
 */

static unsigned char *outptr;              /* where to put the data */
static unsigned outlen;                    /* how much data required */
static unsigned char *pending = NULL;      /* any spare data */
static unsigned pendlen = 0, pendsize = 0; /* length and phys. size of buffer */
int from_backend(void *frontend, int is_stderr, const char *data, int datalen)
{
  unsigned char *p = (unsigned char *)data;
  unsigned len = (unsigned)datalen;

  /*
   * stderr data is just spouted to local stderr and otherwise
   * ignored.
   */
  if (is_stderr) {
    if (len > 0)
      if (fwrite(data, 1, len, stderr) < len)
        /* oh well */;
    return 0;
  }

  /*
   * If this is before the real session begins, just return.
   */
  if (!outptr)
    return 0;

  if ((outlen > 0) && (len > 0)) {
    unsigned used = outlen;
    if (used > len)
      used = len;
    memcpy(outptr, p, used);
    outptr += used;
    outlen -= used;
    p += used;
    len -= used;
  }

  if (len > 0) {
    if (pendsize < pendlen + len) {
      pendsize = pendlen + len + 4096;
      pending = sresize(pending, pendsize, unsigned char);
    }
    memcpy(pending + pendlen, p, len);
    pendlen += len;
  }

  return 0;
}
int from_backend_untrusted(void *frontend_handle, const char *data, int len)
{
  /*
   * No "untrusted" output should get here (the way the code is
   * currently, it's all diverted by FLAG_STDERR).
   */
  assert(!"Unexpected call to from_backend_untrusted()");
  return 0; /* not reached */
}
int from_backend_eof(void *frontend)
{
  /*
   * We expect to be the party deciding when to close the
   * connection, so if we see EOF before we sent it ourselves, we
   * should panic.
   */
  if (!sent_eof) {
    connection_fatal(frontend,
                     "Received unexpected end-of-file from SFTP server");
  }
  return FALSE;
}
int sftp_recvdata(char *buf, int len)
{
  outptr = (unsigned char *)buf;
  outlen = len;

  /*
   * See if the pending-input block contains some of what we
   * need.
   */
  if (pendlen > 0) {
    unsigned pendused = pendlen;
    if (pendused > outlen)
      pendused = outlen;
    memcpy(outptr, pending, pendused);
    memmove(pending, pending + pendused, pendlen - pendused);
    outptr += pendused;
    outlen -= pendused;
    pendlen -= pendused;
    if (pendlen == 0) {
      pendsize = 0;
      sfree(pending);
      pending = NULL;
    }
    if (outlen == 0)
      return 1;
  }

  while (outlen > 0) {
    if (back->exitcode(backhandle) >= 0 || ssh_sftp_loop_iteration() < 0)
      return 0; /* doom */
  }

  return 1;
}
int sftp_senddata(char *buf, int len)
{
  back->send(backhandle, buf, len);
  return 1;
}
int sftp_sendbuffer(void)
{
  return back->sendbuffer(backhandle);
}

/*
 *  Short description of parameters.
 */
static void usage(void)
{
  printf("PuTTY Secure File Transfer (SFTP) client\n");
  printf("%s\n", ver);
  printf("Usage: psftp [options] [user@]host\n");
  printf("Options:\n");
  printf("  -V        print version information and exit\n");
  printf("  -pgpfp    print PGP key fingerprints and exit\n");
  printf("  -b file   use specified batchfile\n");
  printf("  -bc       output batchfile commands\n");
  printf("  -be       don't stop batchfile processing if errors\n");
  printf("  -v        show verbose messages\n");
  printf("  -load sessname  Load settings from saved session\n");
  printf("  -l user   connect with specified username\n");
  printf("  -P port   connect to specified port\n");
  printf("  -pw passw login with specified password\n");
  printf("  -1 -2     force use of particular SSH protocol version\n");
  printf("  -4 -6     force use of IPv4 or IPv6\n");
  printf("  -C        enable compression\n");
  printf("  -i key    private key file for user authentication\n");
  printf("  -noagent  disable use of Pageant\n");
  printf("  -agent    enable use of Pageant\n");
  printf("  -hostkey aa:bb:cc:...\n");
  printf("            manually specify a host key (may be repeated)\n");
  printf("  -batch    disable all interactive prompts\n");
  printf("  -proxycmd command\n");
  printf("            use 'command' as local proxy\n");
  printf("  -sshlog file\n");
  printf("  -sshrawlog file\n");
  printf("            log protocol details to a file\n");
  cleanup_exit(1);
}

static void version(void)
{
  char *buildinfo_text = buildinfo("\n");
  printf("psftp: %s\n%s\n", ver, buildinfo_text);
  sfree(buildinfo_text);
  exit(0);
}

/*
 * Connect to a host.
 */
static int psftp_connect(char *userhost, char *user, int portnumber)
{
  char *host, *realhost;
  const char *err;
  void *logctx;

  /* Separate host and username */
  host = userhost;
  host = strrchr(host, '@');
  if (host == NULL) {
    host = userhost;
  } else {
    *host++ = '\0';
    if (user) {
      printf("psftp: multiple usernames specified; using \"%s\"\n", user);
    } else
      user = userhost;
  }

  /*
   * If we haven't loaded session details already (e.g., from -load),
   * try looking for a session called "host".
   */
  if (!loaded_session) {
    /* Try to load settings for `host' into a temporary config */
    Conf *conf2 = conf_new();
    conf_set_str(conf2, CONF_host, "");
    do_defaults(host, conf2);
    if (conf_get_str(conf2, CONF_host)[0] != '\0') {
      /* Settings present and include hostname */
      /* Re-load data into the real config. */
      do_defaults(host, conf);
    } else {
      /* Session doesn't exist or mention a hostname. */
      /* Use `host' as a bare hostname. */
      conf_set_str(conf, CONF_host, host);
    }
    conf_free(conf2);
  } else {
    /* Patch in hostname `host' to session details. */
    conf_set_str(conf, CONF_host, host);
  }

  /*
   * Force use of SSH. (If they got the protocol wrong we assume the
   * port is useless too.)
   */
  if (conf_get_int(conf, CONF_protocol) != PROT_SSH) {
    conf_set_int(conf, CONF_protocol, PROT_SSH);
    conf_set_int(conf, CONF_port, 22);
  }

  /*
   * If saved session / Default Settings says SSH-1 (`1 only' or `1'),
   * then change it to SSH-2, on the grounds that that's more likely to
   * work for SFTP. (Can be overridden with `-1' option.)
   * But if it says `2 only' or `2', respect which.
   */
  if ((conf_get_int(conf, CONF_sshprot) & ~1) != 2) /* is it 2 or 3? */
    conf_set_int(conf, CONF_sshprot, 2);

  /*
   * Enact command-line overrides.
   */
  cmdline_run_saved(conf);

  /*
   * Muck about with the hostname in various ways.
   */
  {
    char *hostbuf = dupstr(conf_get_str(conf, CONF_host));
    char *host = hostbuf;
    char *p, *q;

    /*
     * Trim leading whitespace.
     */
    host += strspn(host, " \t");

    /*
     * See if host is of the form user@host, and separate out
     * the username if so.
     */
    if (host[0] != '\0') {
      char *atsign = strrchr(host, '@');
      if (atsign) {
        *atsign = '\0';
        conf_set_str(conf, CONF_username, host);
        host = atsign + 1;
      }
    }

    /*
     * Remove any remaining whitespace.
     */
    p = hostbuf;
    q = host;
    while (*q) {
      if (*q != ' ' && *q != '\t')
        *p++ = *q;
      q++;
    }
    *p = '\0';

    conf_set_str(conf, CONF_host, hostbuf);
    sfree(hostbuf);
  }

  /* Set username */
  if (user != NULL && user[0] != '\0') {
    conf_set_str(conf, CONF_username, user);
  }

  if (portnumber)
    conf_set_int(conf, CONF_port, portnumber);

  /*
   * Disable scary things which shouldn't be enabled for simple
   * things like SCP and SFTP: agent forwarding, port forwarding,
   * X forwarding.
   */
  conf_set_int(conf, CONF_x11_forward, 0);
  conf_set_int(conf, CONF_agentfwd, 0);
  conf_set_int(conf, CONF_ssh_simple, TRUE);
  {
    char *key;
    while ((key = conf_get_str_nthstrkey(conf, CONF_portfwd, 0)) != NULL)
      conf_del_str_str(conf, CONF_portfwd, key);
  }

  /* Set up subsystem name. */
  conf_set_str(conf, CONF_remote_cmd, "sftp");
  conf_set_int(conf, CONF_ssh_subsys, TRUE);
  conf_set_int(conf, CONF_nopty, TRUE);

  /*
   * Set up fallback option, for SSH-1 servers or servers with the
   * sftp subsystem not enabled but the server binary installed
   * in the usual place. We only support fallback on Unix
   * systems, and we use a kludgy piece of shellery which should
   * try to find sftp-server in various places (the obvious
   * systemwide spots /usr/lib and /usr/local/lib, and then the
   * user's PATH) and finally give up.
   *
   *   test -x /usr/lib/sftp-server && exec /usr/lib/sftp-server
   *   test -x /usr/local/lib/sftp-server && exec /usr/local/lib/sftp-server
   *   exec sftp-server
   *
   * the idea being that this will attempt to use either of the
   * obvious pathnames and then give up, and when it does give up
   * it will print the preferred pathname in the error messages.
   */
  conf_set_str(conf,
               CONF_remote_cmd2,
               "test -x /usr/lib/sftp-server &&"
               " exec /usr/lib/sftp-server\n"
               "test -x /usr/local/lib/sftp-server &&"
               " exec /usr/local/lib/sftp-server\n"
               "exec sftp-server");
  conf_set_int(conf, CONF_ssh_subsys2, FALSE);

  back = &ssh_backend;

  logctx = log_init(NULL, conf);
  console_provide_logctx(logctx);

  platform_psftp_pre_conn_setup();

  err = back->init(NULL,
                   &backhandle,
                   conf,
                   conf_get_str(conf, CONF_host),
                   conf_get_int(conf, CONF_port),
                   &realhost,
                   0,
                   conf_get_int(conf, CONF_tcp_keepalives));
  if (err != NULL) {
    fprintf(stderr, "ssh_init: %s\n", err);
    return 1;
  }
  back->provide_logctx(backhandle, logctx);
  while (!back->sendok(backhandle)) {
    if (back->exitcode(backhandle) >= 0)
      return 1;
    if (ssh_sftp_loop_iteration() < 0) {
      fprintf(stderr, "ssh_init: error during SSH connection setup\n");
      return 1;
    }
  }
  if (verbose && realhost != NULL)
    printf("Connected to %s\n", realhost);
  if (realhost != NULL)
    sfree(realhost);
  return 0;
}

void cmdline_error(const char *p, ...)
{
  va_list ap;
  fprintf(stderr, "psftp: ");
  va_start(ap, p);
  vfprintf(stderr, p, ap);
  va_end(ap);
  fprintf(stderr, "\n       try typing \"psftp -h\" for help\n");
  exit(1);
}

const int share_can_be_downstream = TRUE;
const int share_can_be_upstream = FALSE;

/*
 * Main program. Parse arguments etc.
 */
int psftp_main(int argc, char *argv[])
{
  int i, ret;
  int portnumber = 0;
  char *userhost, *user;
  int mode = 0;
  int modeflags = 0;
  char *batchfile = NULL;

  flags = FLAG_STDERR | FLAG_INTERACTIVE
#ifdef FLAG_SYNCAGENT
          | FLAG_SYNCAGENT
#endif
      ;
  cmdline_tooltype = TOOLTYPE_FILETRANSFER;
  sk_init();

  userhost = user = NULL;

  /* Load Default Settings before doing anything else. */
  conf = conf_new();
  do_defaults(NULL, conf);
  loaded_session = FALSE;

  for (i = 1; i < argc; i++) {
    int ret;
    if (argv[i][0] != '-') {
      if (userhost)
        usage();
      else
        userhost = dupstr(argv[i]);
      continue;
    }
    ret = cmdline_process_param(
        argv[i], i + 1 < argc ? argv[i + 1] : NULL, 1, conf);
    if (ret == -2) {
      cmdline_error("option \"%s\" requires an argument", argv[i]);
    } else if (ret == 2) {
      i++; /* skip next argument */
    } else if (ret == 1) {
      /* We have our own verbosity in addition to `flags'. */
      if (flags & FLAG_VERBOSE)
        verbose = 1;
    } else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "-?") == 0 ||
               strcmp(argv[i], "--help") == 0) {
      usage();
    } else if (strcmp(argv[i], "-pgpfp") == 0) {
      pgp_fingerprints();
      return 1;
    } else if (strcmp(argv[i], "-V") == 0 ||
               strcmp(argv[i], "--version") == 0) {
      version();
    } else if (strcmp(argv[i], "-batch") == 0) {
      console_batch_mode = 1;
    } else if (strcmp(argv[i], "-b") == 0 && i + 1 < argc) {
      mode = 1;
      batchfile = argv[++i];
    } else if (strcmp(argv[i], "-bc") == 0) {
      modeflags = modeflags | 1;
    } else if (strcmp(argv[i], "-be") == 0) {
      modeflags = modeflags | 2;
    } else if (strcmp(argv[i], "--") == 0) {
      i++;
      break;
    } else {
      cmdline_error("unknown option \"%s\"", argv[i]);
    }
  }
  argc -= i;
  argv += i;
  back = NULL;

  /*
   * If the loaded session provides a hostname, and a hostname has not
   * otherwise been specified, pop it in `userhost' so that
   * `psftp -load sessname' is sufficient to start a session.
   */
  if (!userhost && conf_get_str(conf, CONF_host)[0] != '\0') {
    userhost = dupstr(conf_get_str(conf, CONF_host));
  }

  /*
   * If a user@host string has already been provided, connect to
   * it now.
   */
  if (userhost) {
    int ret;
    ret = psftp_connect(userhost, user, portnumber);
    sfree(userhost);
    if (ret)
      return 1;
    if (do_sftp_init())
      return 1;
  } else {
    printf("psftp: no hostname specified; use \"open host.name\""
           " to connect\n");
  }

  ret = do_sftp(mode, modeflags, batchfile);

  if (back != NULL && back->connected(backhandle)) {
    char ch;
    back->special(backhandle, TS_EOF);
    sent_eof = TRUE;
    sftp_recvdata(&ch, 1);
  }
  do_sftp_cleanup();
  random_save_seed();
  cmdline_cleanup();
  console_provide_logctx(NULL);
  sk_cleanup();

  return ret;
}