psftp.c

putty

/*
 * 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"

/*
 * 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 Config cfg;

/* ----------------------------------------------------------------------
 * 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(char *name)
{
    char *fullname, *canonname;
    struct sftp_packet *pktin;
    struct sftp_request *req, *rreq;

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

    sftp_register(req = fxp_realpath_send(fullname));
    rreq = sftp_find_request(pktin = sftp_recv());
    assert(rreq == req);
    canonname = fxp_realpath_recv(pktin, rreq);

    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) {
	    sftp_register(req = fxp_realpath_send("/"));
	} else {
	    sftp_register(req = fxp_realpath_send(fullname));
	}
	rreq = sftp_find_request(pktin = sftp_recv());
	assert(rreq == req);
	canonname = fxp_realpath_recv(pktin, rreq);

	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;
    }
}

/*
 * Return a pointer to the portion of str that comes after the last
 * slash (or backslash or colon, if `local' is TRUE).
 */
static char *stripslashes(char *str, int local)
{
    char *p;

    if (local) {
        p = strchr(str, ':');
        if (p) str = p+1;
    }

    p = strrchr(str, '/');
    if (p) str = p+1;

    if (local) {
	p = strrchr(str, '\\');
	if (p) str = p+1;
    }

    return str;
}

/*
 * 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, *rreq;
    struct fxp_xfer *xfer;
    uint64 offset;
    WFile *file;
    int ret, shown_err = FALSE;

    /*
     * 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) {
	struct fxp_attrs attrs;
	int result;

	sftp_register(req = fxp_stat_send(fname));
	rreq = sftp_find_request(pktin = sftp_recv());
	assert(rreq == req);
	result = fxp_stat_recv(pktin, rreq, &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.
	     */
	    sftp_register(req = fxp_opendir_send(fname));
	    rreq = sftp_find_request(pktin = sftp_recv());
	    assert(rreq == req);
	    dirhandle = fxp_opendir_recv(pktin, rreq);

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

		sftp_register(req = fxp_readdir_send(dirhandle));
		rreq = sftp_find_request(pktin = sftp_recv());
		assert(rreq == req);
		names = fxp_readdir_recv(pktin, rreq);

		if (names == NULL) {
		    if (fxp_error_type() == SSH_FX_EOF)
			break;
		    printf("%s: reading directory: %s\n", fname, fxp_error());
		    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);
	    }
	    sftp_register(req = fxp_close_send(dirhandle));
	    rreq = sftp_find_request(pktin = sftp_recv());
	    assert(rreq == req);
	    fxp_close_recv(pktin, rreq);

	    /*
	     * 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.
	     */
	    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;
                    if (outfname)
                        nextoutfname = dir_file_cat(outfname,
                                                    ournames[i]->filename);
                    else
                        nextoutfname = dupstr(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);
		if (outfname)
		    nextoutfname = dir_file_cat(outfname,
						ournames[i]->filename);
		else
		    nextoutfname = dupstr(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;
	}
    }

    sftp_register(req = fxp_open_send(fname, SSH_FXF_READ));
    rreq = sftp_find_request(pktin = sftp_recv());
    assert(rreq == req);
    fh = fxp_open_recv(pktin, rreq);

    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);
    }

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

	sftp_register(req = fxp_close_send(fh));
	rreq = sftp_find_request(pktin = sftp_recv());
	assert(rreq == req);
	fxp_close_recv(pktin, rreq);

	return 0;
    }

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

    sftp_register(req = fxp_close_send(fh));
    rreq = sftp_find_request(pktin = sftp_recv());
    assert(rreq == req);
    fxp_close_recv(pktin, rreq);

    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, *rreq;
    uint64 offset;
    RFile *file;
    int ret, err, eof;