freebsd-skq/sbin/mount_std/mount_std.c
mux b018bad669 Fix the fallback to mount(2) with RELENG_4 kernels and -CURRENT
utilities by catching SIGSYS.

Submitted by:	bde
2002-05-05 10:08:04 +00:00

179 lines
5.0 KiB
C

/*
* Copyright (c) 1990, 1992 Jan-Simon Pendry
* Copyright (c) 1992, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1992, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/uio.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include "mntopts.h"
static struct mntopt mopts[] = {
MOPT_STDOPTS,
{ NULL }
};
static const char *fsname;
static volatile sig_atomic_t caughtsig;
static void usage(void) __dead2;
static void
catchsig(int s)
{
caughtsig = 1;
}
int
main(argc, argv)
int argc;
char *argv[];
{
int ch, mntflags;
char mntpath[MAXPATHLEN];
struct vfsconf vfc;
struct iovec iov[4];
int error;
/*
* XXX
* mount(8) calls the mount programs with an argv[0] which is
* /just/ the filesystem name. So, if there is no underscore
* in argv[0], we assume that we are being called from mount(8)
* and that argv[0] is thus the name of the filesystem type.
*/
fsname = strrchr(argv[0], '_');
if (fsname) {
if (strcmp(fsname, "_std") == 0)
errx(EX_USAGE, "argv[0] must end in _fsname");
fsname++;
} else {
fsname = argv[0];
}
mntflags = 0;
while ((ch = getopt(argc, argv, "o:")) != -1)
switch (ch) {
case 'o':
getmntopts(optarg, mopts, &mntflags, 0);
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc != 2)
usage();
error = getvfsbyname(fsname, &vfc);
if (error && vfsisloadable(fsname)) {
if(vfsload(fsname))
err(EX_OSERR, "vfsload(%s)", fsname);
endvfsent();
error = getvfsbyname(fsname, &vfc);
}
if (error)
errx(EX_OSERR, "%s filesystem not available", fsname);
/* resolve the mountpoint with realpath(3) */
(void)checkpath(argv[1], mntpath);
iov[0].iov_base = "fstype";
iov[0].iov_len = sizeof("fstype");
iov[1].iov_base = vfc.vfc_name;
iov[1].iov_len = strlen(vfc.vfc_name) + 1;
iov[2].iov_base = "fspath";
iov[2].iov_len = sizeof("fstype");
iov[3].iov_base = mntpath;
iov[3].iov_len = strlen(mntpath) + 1;
/*
* nmount(2) would kill us with SIGSYS if the kernel doesn't have it.
* This design bug is inconvenient. We must catch the signal and not
* just ignore it because of a plain bug: nmount(2) would return
* EINVAL instead of the correct ENOSYS if the kernel doesn't have it
* and we don't let the signal kill us. EINVAL is too ambiguous.
* This bug in 4.4BSD-Lite1 was fixed in 4.4BSD-Lite2 but is still in
* FreeBSD-5.0.
*/
signal(SIGSYS, catchsig);
error = nmount(iov, 4, mntflags);
signal(SIGSYS, SIG_DFL);
/*
* Try with the old mount syscall in the case
* this filesystem has not been converted yet,
* or the user didn't recompile his kernel.
*/
if (error && (errno == EOPNOTSUPP || errno == ENOSYS || caughtsig))
error = mount(vfc.vfc_name, mntpath, mntflags, NULL);
if (error)
err(EX_OSERR, NULL);
exit(0);
}
void
usage()
{
(void)fprintf(stderr,
"usage: mount_%s [-o options] what_to_mount mount_point\n",
fsname);
exit(EX_USAGE);
}