xref: /src/usr.sbin/puffs/mount_psshfs/psshfs.c

/*	$NetBSD: psshfs.c,v 1.34.4.1 2007/11/06 23:36:32 matt Exp $	*/

/*
 * Copyright (c) 2006  Antti Kantee.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * psshfs: puffs sshfs
 *
 * psshfs implements sshfs functionality on top of puffs making it
 * possible to mount a filesystme through the sftp service.
 *
 * psshfs can execute multiple operations in "parallel" by using the
 * puffs_cc framework for continuations.
 *
 * Concurrency control is handled currently by vnode locking (this
 * will change in the future).  Context switch locations are easy to
 * find by grepping for puffs_framebuf_enqueue_cc().
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: psshfs.c,v 1.34.4.1 2007/11/06 23:36:32 matt Exp $");
#endif /* !lint */

#include <sys/types.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <mntopts.h>
#include <paths.h>
#include <poll.h>
#include <puffs.h>
#include <signal.h>
#include <stdlib.h>
#include <util.h>
#include <unistd.h>

#include "psshfs.h"

static void	pssh_connect(struct psshfs_ctx *, char **);
static void	usage(void);
static void	add_ssharg(char ***, int *, char *);

#define SSH_PATH "/usr/bin/ssh"

unsigned int max_reads;

static void
add_ssharg(char ***sshargs, int *nargs, char *arg)
{

	*sshargs = realloc(*sshargs, (*nargs + 2) * sizeof(char*));
	if (!*sshargs)
		err(1, "realloc");
	(*sshargs)[(*nargs)++] = arg;
	(*sshargs)[*nargs] = NULL;
}

static void
usage()
{

	fprintf(stderr, "usage: %s "
	    "[-es] [-O sshopt=value] [-o opts] user@host:path mountpath\n",
	    getprogname());
	exit(1);
}

int
main(int argc, char *argv[])
{
	struct psshfs_ctx pctx;
	struct puffs_usermount *pu;
	struct puffs_ops *pops;
	mntoptparse_t mp;
	char **sshargs;
	char *userhost;
	char *hostpath;
	int mntflags, pflags, ch;
	int detach;
	int exportfs;
	int nargs, x;

	setprogname(argv[0]);

	if (argc < 3)
		usage();

	mntflags = pflags = exportfs = nargs = 0;
	detach = 1;
	sshargs = NULL;
	add_ssharg(&sshargs, &nargs, SSH_PATH);
	add_ssharg(&sshargs, &nargs, "-axs");
	add_ssharg(&sshargs, &nargs, "-oClearAllForwardings=yes");

	while ((ch = getopt(argc, argv, "eo:O:r:s")) != -1) {
		switch (ch) {
		case 'e':
			exportfs = 1;
			break;
		case 'O':
			add_ssharg(&sshargs, &nargs, "-o");
			add_ssharg(&sshargs, &nargs, optarg);
			break;
		case 'o':
			mp = getmntopts(optarg, puffsmopts, &mntflags, &pflags);
			if (mp == NULL)
				err(1, "getmntopts");
			freemntopts(mp);
			break;
		case 'r':
			max_reads = atoi(optarg);
			break;
		case 's':
			detach = 0;
			break;
		default:
			usage();
			/*NOTREACHED*/
		}
	}
	argc -= optind;
	argv += optind;

	if (pflags & PUFFS_FLAG_OPDUMP)
		detach = 0;
	pflags |= PUFFS_FLAG_BUILDPATH;
	pflags |= PUFFS_KFLAG_WTCACHE | PUFFS_KFLAG_IAONDEMAND;

	if (argc != 2)
		usage();

	PUFFSOP_INIT(pops);

	PUFFSOP_SET(pops, psshfs, fs, unmount);
	PUFFSOP_SETFSNOP(pops, sync); /* XXX */
	PUFFSOP_SETFSNOP(pops, statvfs);
	PUFFSOP_SET(pops, psshfs, fs, nodetofh);
	PUFFSOP_SET(pops, psshfs, fs, fhtonode);

	PUFFSOP_SET(pops, psshfs, node, lookup);
	PUFFSOP_SET(pops, psshfs, node, create);
	PUFFSOP_SET(pops, psshfs, node, open);
	PUFFSOP_SET(pops, psshfs, node, close);
	PUFFSOP_SET(pops, psshfs, node, mmap);
	PUFFSOP_SET(pops, psshfs, node, inactive);
	PUFFSOP_SET(pops, psshfs, node, readdir);
	PUFFSOP_SET(pops, psshfs, node, getattr);
	PUFFSOP_SET(pops, psshfs, node, setattr);
	PUFFSOP_SET(pops, psshfs, node, mkdir);
	PUFFSOP_SET(pops, psshfs, node, remove);
	PUFFSOP_SET(pops, psshfs, node, readlink);
	PUFFSOP_SET(pops, psshfs, node, rmdir);
	PUFFSOP_SET(pops, psshfs, node, symlink);
	PUFFSOP_SET(pops, psshfs, node, rename);
	PUFFSOP_SET(pops, psshfs, node, read);
	PUFFSOP_SET(pops, psshfs, node, write);
	PUFFSOP_SET(pops, psshfs, node, reclaim);

	pu = puffs_init(pops, argv[0], "psshfs", &pctx, pflags);
	if (pu == NULL)
		err(1, "puffs_init");

	memset(&pctx, 0, sizeof(pctx));
	pctx.mounttime = time(NULL);

	userhost = argv[0];
	hostpath = strchr(userhost, ':');
	if (hostpath) {
		*hostpath++ = '\0';
		pctx.mountpath = hostpath;
	} else
		pctx.mountpath = ".";

	add_ssharg(&sshargs, &nargs, argv[0]);
	add_ssharg(&sshargs, &nargs, "sftp");

	pssh_connect(&pctx, sshargs);

	if (puffs_setblockingmode(pu, PUFFSDEV_NONBLOCK) == -1)
		err(1, "setblockingmode");
	if (exportfs)
		puffs_setfhsize(pu, sizeof(struct psshfs_fid),
		    PUFFS_FHFLAG_NFSV2 | PUFFS_FHFLAG_NFSV3);

	if (psshfs_domount(pu) != 0)
		errx(1, "psshfs_domount");
	x = 1;
	if (ioctl(pctx.sshfd, FIONBIO, &x) == -1)
		err(1, "nonblocking descriptor");

	puffs_framev_init(pu, psbuf_read, psbuf_write, psbuf_cmp, NULL,
	    puffs_framev_unmountonclose);
	if (puffs_framev_addfd(pu, pctx.sshfd,
	    PUFFS_FBIO_READ | PUFFS_FBIO_WRITE) == -1)
		err(1, "framebuf addfd");

	if (detach)
		if (daemon(1, 1) == -1)
			err(1, "daemon");

	if (puffs_mount(pu, argv[1], mntflags, puffs_getroot(pu)) == -1)
		err(1, "puffs_mount");
	if (puffs_mainloop(pu) == -1)
		err(1, "mainloop");

	return 0;
}

static void
pssh_connect(struct psshfs_ctx *pctx, char **sshargs)
{
	int fds[2];
	pid_t pid;
	int dnfd;

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == -1)
		err(1, "socketpair");

	pid = fork();
	switch (pid) {
	case -1:
		err(1, "fork");
		/*NOTREACHED*/
	case 0: /* child */
		if (dup2(fds[0], STDIN_FILENO) == -1)
			err(1, "child dup2");
		if (dup2(fds[0], STDOUT_FILENO) == -1)
			err(1, "child dup2");
		close(fds[0]);
		close(fds[1]);

		dnfd = open(_PATH_DEVNULL, O_RDWR);
		if (dnfd != -1)
			dup2(dnfd, STDERR_FILENO);

		execvp(sshargs[0], sshargs);
		break;
	default:
		pctx->sshpid = pid;
		pctx->sshfd = fds[1];
		close(fds[0]);
		break;
	}
}