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Introduce uu_lock(), uu_unlock() and uu_lockerr() 

into libutil.
Obtained from: FreeBSD
Reviewed by: Theo
OPENBSD_2_3
bri 27 years ago
parent
7853ecaa8b
commit
55694d3e32
6 changed files with 394 additions and 6 deletions
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  1. +2
    -1
      src/include/paths.h
  2. +7
    -3
      src/lib/libutil/Makefile
  3. +1
    -1
      src/lib/libutil/shlib_version
  4. +13
    -1
      src/lib/libutil/util.h
  5. +160
    -0
      src/lib/libutil/uucplock.3
  6. +211
    -0
      src/lib/libutil/uucplock.c

+ 2
- 1
src/include/paths.h View File

@ -1,4 +1,4 @@
/* $OpenBSD: paths.h,v 1.9 1997/08/29 18:05:38 mickey Exp $ */
/* $OpenBSD: paths.h,v 1.10 1997/11/09 00:29:02 bri Exp $ */
/* $NetBSD: paths.h,v 1.7 1994/10/26 00:56:12 cgd Exp $ */
/*
@ -71,6 +71,7 @@
#define _PATH_BOOTDIR "/usr/mdec/"
#define _PATH_DEV "/dev/"
#define _PATH_TMP "/tmp/"
#define _PATH_UUCPLOCK "/var/spool/lock/"
#define _PATH_VARDB "/var/db/"
#define _PATH_VARRUN "/var/run/"
#define _PATH_VARTMP "/var/tmp/"


+ 7
- 3
src/lib/libutil/Makefile View File

@ -1,4 +1,4 @@
# $OpenBSD: Makefile,v 1.14 1997/06/17 10:10:41 niklas Exp $
# $OpenBSD: Makefile,v 1.15 1997/11/09 00:29:13 bri Exp $
# $NetBSD: Makefile,v 1.8 1996/05/16 07:03:28 thorpej Exp $
LIB= util
@ -6,11 +6,12 @@ CFLAGS+=-DLIBC_SCCS
HDRS= util.h scsi.h
SRCS= getmaxpartitions.c getrawpartition.c login.c login_tty.c logout.c \
logwtmp.c opendev.c passwd.c pty.c readlabel.c scsi.c login_fbtab.c
logwtmp.c opendev.c passwd.c pty.c readlabel.c scsi.c login_fbtab.c \
uucplock.c
# XXX need login_fbtab.3
MAN= getmaxpartitions.3 getrawpartition.3 login.3 opendev.3 openpty.3 \
pw_init.3 pw_lock.3 readlabelfs.3 scsi.3 pw_getconf.3
pw_init.3 pw_lock.3 readlabelfs.3 scsi.3 pw_getconf.3 uucplock.3
MLINKS+=login.3 logout.3
MLINKS+=login.3 logwtmp.3
@ -36,6 +37,9 @@ MLINKS+=scsi.3 SCSIREQ_ERROR.3
MLINKS+=scsi.3 scsi_open.3
MLINKS+=scsi.3 scsi_debug.3
MLINKS+=scsi.3 scsi_debug_output.3
MLINKS+=uucplock.3 uu_lock.3
MLINKS+=uucplock.3 uu_unlock.3
MLINKS+=uucplock.3 uu_lockerr.3
includes:
@cd ${.CURDIR}; for i in $(HDRS); do \


+ 1
- 1
src/lib/libutil/shlib_version View File

@ -1,2 +1,2 @@
major=4
minor=0
minor=1

+ 13
- 1
src/lib/libutil/util.h View File

@ -1,4 +1,4 @@
/* $OpenBSD: util.h,v 1.6 1997/06/17 10:10:43 niklas Exp $ */
/* $OpenBSD: util.h,v 1.7 1997/11/09 00:29:14 bri Exp $ */
/* $NetBSD: util.h,v 1.2 1996/05/16 07:00:22 thorpej Exp $ */
/*-
@ -76,6 +76,18 @@ int getmaxpartitions __P((void));
int getrawpartition __P((void));
void login_fbtab __P((char *, uid_t, gid_t));
char *readlabelfs __P((char *, int));
const char *uu_lockerr __P((int _uu_lockresult));
int uu_lock __P((const char *_ttyname));
int uu_unlock __P((const char *_ttyname));
__END_DECLS
#define UU_LOCK_INUSE (1)
#define UU_LOCK_OK (0)
#define UU_LOCK_OPEN_ERR (-1)
#define UU_LOCK_READ_ERR (-2)
#define UU_LOCK_CREAT_ERR (-3)
#define UU_LOCK_WRITE_ERR (-4)
#define UU_LOCK_LINK_ERR (-5)
#define UU_LOCK_TRY_ERR (-6)
#endif /* !_UTIL_H_ */

+ 160
- 0
src/lib/libutil/uucplock.3 View File

@ -0,0 +1,160 @@
.\"
.\" 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 DEVELOPERS ``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 DEVELOPERS 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.
.\"
.\" $Id: uucplock.3,v 1.1 1997/11/09 00:29:14 bri Exp $
.\" "
.Dd March 30, 1997
.Os
.Dt uucplock 3
.Sh NAME
.Nm uu_lock ,
.Nm uu_unlock ,
.Nm uu_lockerr
.Nd acquire and release control of a serial device
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <libutil.h>
.Ft int
.Fn uu_lock "const char *ttyname"
.Ft int
.Fn uu_unlock "const char *ttyname"
.Ft const char *
.Fn uu_lockerr "int uu_lockresult"
.Pp
Link with
.Va -lutil
on the
.Xr cc 1
command line.
.Sh DESCRIPTION
The
.Fn uu_lock
function attempts to create a lock file called
.Pa /var/spool/lock/LCK..
with a suffix given by the passed
.Fa ttyname .
If the file already exists, it is expected to contain the process
id of the locking program.
.Pp
If the file does not already exist, or the owning process given by
the process id found in the lock file is no longer running,
.Fn uu_lock
will write its own process id into the file and return success.
.Pp
.Fn uu_unlock
removes the lockfile created by
.Fn uu_lock
for the given
.Fa ttyname .
Care should be taken that
.Fn uu_lock
was successful before calling
.Fn uu_unlock .
.Pp
.Fn uu_lockerr
returns an error string representing the error
.Fa uu_lockresult ,
as returned from
.Fn uu_lock .
.Sh RETURN VALUES
.Fn uu_unlock
returns 0 on success and -1 on failure.
.Pp
.Fn uu_lock
may return any of the following values:
.Pp
.Dv UU_LOCK_INUSE:
The lock is in use by another process.
.Pp
.Dv UU_LOCK_OK:
The lock was successfully created.
.Pp
.Dv UU_LOCK_OPEN_ERR:
The lock file could not be opened via
.Xr open 2 .
.Pp
.Dv UU_LOCK_READ_ERR:
The lock file could not be read via
.Xr read 2 .
.Pp
.Dv UU_LOCK_CREAT_ERR:
Can't create temporary lock file via
.Xr creat 2 .
.Pp
.Dv UU_LOCK_WRITE_ERR:
The current process id could not be written to the lock file via a call to
.Xr write 2 .
.Pp
.Dv UU_LOCK_LINK_ERR:
Can't link temporary lock file via
.Xr link 2 .
.Pp
.Dv UU_LOCK_TRY_ERR:
Locking attempts are failed after 5 tries.
.Pp
If a value of
.Dv UU_LOCK_OK
is passed to
.Fn uu_lockerr ,
an empty string is returned.
Otherwise, a string specifying
the reason for failure is returned.
.Fn uu_lockerr
uses the current value of
.Va errno
to determine the exact error. Care should be made not to allow
.Va errno
to be changed between calls to
.Fn uu_lock
and
.Fn uu_lockerr .
.Sh ERRORS
If
.Fn uu_lock
returns one of the four error values above, the global value
.Va errno
can be used to determine the cause. Refer to the respective manual pages
for further details.
.Pp
.Fn uu_unlock
will set the global variable
.Va errno
to reflect the reason that the lock file could not be removed.
Refer to the description of
.Xr unlink 2
for further details.
.Sh SEE ALSO
.Xr lseek 2 ,
.Xr open 2 ,
.Xr read 2 ,
.Xr write 2
.Sh BUGS
It is possible that a stale lock is not recognised as such if a new
processes is assigned the same processes id as the program that left
the stale lock.
.Pp
The calling process must have write permissions to the
.Pa /var/spool/lock
directory. There is no mechanism in place to ensure that the
permissions of this directory are the same as those of the
serial devices that might be locked.

+ 211
- 0
src/lib/libutil/uucplock.c View File

@ -0,0 +1,211 @@
/*
* Copyright (c) 1988, 1993
* The Regents of the University of California. 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.
* 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.
*
* $Id: uucplock.c,v 1.1 1997/11/09 00:29:15 bri Exp $
*
*/
#ifndef lint
static const char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#include <sys/types.h>
#include <sys/file.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <paths.h>
#include <string.h>
#include "util.h"
#define MAXTRIES 5
#define LOCKTMP "LCKTMP..%d"
#define LOCKFMT "LCK..%s"
#define GORET(level, val) { err = errno; uuerr = (val); \
goto __CONCAT(ret, level); }
/* Forward declarations */
static int put_pid __P((int fd, pid_t pid));
static pid_t get_pid __P((int fd,int *err));
/*
* uucp style locking routines
*/
int
uu_lock(ttyname)
const char *ttyname;
{
int fd, tmpfd, i;
pid_t pid;
char lckname[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN],
lcktmpname[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
int err, uuerr;
pid = getpid();
(void)snprintf(lcktmpname, sizeof(lcktmpname), _PATH_UUCPLOCK LOCKTMP,
pid);
(void)snprintf(lckname, sizeof(lckname), _PATH_UUCPLOCK LOCKFMT,
ttyname);
if ((tmpfd = creat(lcktmpname, 0664)) < 0)
GORET(0, UU_LOCK_CREAT_ERR);
for (i = 0; i < MAXTRIES; i++) {
if (link (lcktmpname, lckname) < 0) {
if (errno != EEXIST)
GORET(1, UU_LOCK_LINK_ERR);
/*
* file is already locked
* check to see if the process holding the lock
* still exists
*/
if ((fd = open(lckname, O_RDONLY)) < 0)
GORET(1, UU_LOCK_OPEN_ERR);
if ((pid = get_pid (fd, &err)) == -1)
GORET(2, UU_LOCK_READ_ERR);
close(fd);
if (kill(pid, 0) == 0 || errno != ESRCH)
GORET(1, UU_LOCK_INUSE);
/*
* The process that locked the file isn't running, so
* we'll lock it ourselves
*/
(void)unlink(lckname);
} else {
if (!put_pid (tmpfd, pid))
GORET(3, UU_LOCK_WRITE_ERR);
break;
}
}
GORET(1, (i >= MAXTRIES) ? UU_LOCK_TRY_ERR : UU_LOCK_OK);
ret3:
(void)unlink(lckname);
goto ret1;
ret2:
(void)close(fd);
ret1:
(void)close(tmpfd);
(void)unlink(lcktmpname);
ret0:
errno = err;
return uuerr;
}
int
uu_unlock(ttyname)
const char *ttyname;
{
char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
(void)snprintf(tbuf, sizeof(tbuf), _PATH_UUCPLOCK LOCKFMT, ttyname);
return unlink(tbuf);
}
const char *
uu_lockerr(uu_lockresult)
int uu_lockresult;
{
static char errbuf[128];
char *fmt;
switch (uu_lockresult) {
case UU_LOCK_INUSE:
return "device in use";
case UU_LOCK_OK:
return "";
case UU_LOCK_OPEN_ERR:
fmt = "open error: %s";
break;
case UU_LOCK_READ_ERR:
fmt = "read error: %s";
break;
case UU_LOCK_CREAT_ERR:
fmt = "creat error: %s";
break;
case UU_LOCK_WRITE_ERR:
fmt = "write error: %s";
break;
case UU_LOCK_LINK_ERR:
fmt = "link error: %s";
break;
case UU_LOCK_TRY_ERR:
fmt = "too many tries: %s";
break;
default:
fmt = "undefined error: %s";
break;
}
(void)snprintf(errbuf, sizeof(errbuf), fmt, strerror(errno));
return errbuf;
}
static int
put_pid(fd, pid)
int fd;
pid_t pid;
{
char buf[32];
int len;
len = sprintf (buf, "%10d\n", pid);
return write (fd, buf, len) == len && ftruncate(fd, len);
}
static pid_t
get_pid(fd, err)
int fd;
int *err;
{
int bytes_read;
char buf[32];
pid_t pid;
bytes_read = read (fd, buf, sizeof (buf) - 1);
if (bytes_read > 0) {
buf[bytes_read] = '\0';
pid = strtoul (buf, (char **) NULL, 10);
} else {
pid = -1;
*err = bytes_read ? errno : EINVAL;
}
return pid;
}

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