svr4pkg/libinst/lockinst.c

	lockinst.c revision 5c51f1241dbbdf2656d0e10011981411ed0c9673
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */


#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <pkglocs.h>
#include <locale.h>
#include <libintl.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/fault.h>
#include <sys/syscall.h>
#include <pkglib.h>
#include "libadm.h"

extern int errno;

#define ST_QUIT 1
#define ST_OK   0

#define LOCKFILE    ".lockfile"
#define LCKBUFSIZ   128
#define LOCKWAIT    20  /* seconds between retries */
#define LOCKRETRY   10  /* number of retries for a DB lock */
#define LF_SIZE     128 /* size of governing lock file */

#define MSG_WTING   "NOTE: Waiting for access to the package database."
#define MSG_XWTING  "NOTE: Waiting for exclusive access to the package " \
                "database."
#define MSG_WTFOR   "NOTE: Waiting for %s of %s to complete."
#define WRN_CLRLOCK "WARNING: Stale lock installed for %s, pkg %s quit " \
                "in %s state."
#define WRN_CLRLOCK1    "Removing lock."
#define ERR_MKLOCK  "unable to create governing lock file <%s>."
#define ERR_NOLOCK  "unable to install governing lock on <%s>."
#define ERR_NOOPEN  "unable to open <%s>."
#define ERR_LCKTBL  "unable to lock <%s> - lock table full."
#define ERR_LCKREM  "unable to lock <%s> - remote host unavailable."
#define ERR_BADLCK  "unable to lock <%s> - unknown error."
#define ERR_DEADLCK "unable to lock <%s> - deadlock condition."

static pid_t lock_pid;
static int lock_fd, lock_is_applied;
static char lock_name[PKGSIZ];
static char lock_pkg[PKGSIZ];
static char lock_place[PKGSIZ];
static unsigned int lock_state;
static char lockbuf[LCKBUFSIZ];
static char lockpath[PATH_MAX];

#define LOCK_NAME_OLD_PKG   "old version pkg command"
#define LOCK_PKG_UNKNOWN    "unknown package"
#define LOCK_PLACE_UNKNOWN  "unknown"

/*
 * This function writes the PID, effective utility name, package name,
 * current progress of the utility and the exit state to the lockfile in
 * support of post mortem operations.
 */
static int
wrlockdata(int fd, int this_pid, char *this_name,
    char *this_pkg, char *this_place, unsigned int this_state)
{
    if (this_pid < 0 || *this_name == '\000')
        return (0);

    (void) memset(lockbuf, 0, LCKBUFSIZ);

    (void) snprintf(lockbuf, sizeof (lockbuf),
            "%d %s %s %s %d\n", this_pid, this_name, this_pkg,
            this_place, this_state);

    (void) lseek(fd, 0, SEEK_SET);
    if (write(fd, lockbuf, LF_SIZE) == LF_SIZE)
        return (1);
    else
        return (0);
}

/*
 * This function reads the lockfile to obtain the PID and name of the lock
 * holder. Upon those rare circumstances that an older version of pkgadd
 * created the lock, this detects that zero-length file and provides the
 * appropriate data. Since this data is only used if an actual lock (from
 * lockf()) is detected, a manually created .lockfile will not result in a
 * message.
 */
static void
rdlockdata(int fd)
{
    (void) lseek(fd, 0, SEEK_SET);
    if (read(fd, lockbuf, LF_SIZE) != LF_SIZE) {
        lock_pid = 0;
        (void) strlcpy(lock_name, LOCK_NAME_OLD_PKG,
                        sizeof (lock_name));

        (void) strlcpy(lock_pkg, LOCK_PKG_UNKNOWN,
                        sizeof (lock_pkg));

        (void) strlcpy(lock_place, LOCK_PLACE_UNKNOWN,
                        sizeof (lock_place));

        lock_state = ST_OK;
    } else {
        /* LINTED format argument contains unbounded string specifier */
        (void) sscanf(lockbuf, "%ld %s %s %s %u", &lock_pid,
            lock_name, lock_pkg, lock_place, &lock_state);
    }
}

static void
do_alarm(int n)
{
#ifdef lint
    int i = n;
    n = i;
#endif  /* lint */
    (void) signal(SIGALRM, do_alarm);
    (void) alarm(LOCKWAIT);
}

/*
 * This establishes a locked status file for a pkgadd, pkgrm or swmtool - any
 * of the complex package processes. Since numerous packages currently use
 * installf and removef in preinstall scripts, we can't enforce a contents
 * file write lock throughout the install process. In 2.7 we will enforce the
 * write lock and allow this lock to serve as a simple information carrier
 * which can be used by installf and removef too.
 * Arguments:
 *  util_name - the name of the utility that is claiming the lock
 *  pkg_name - the package that is being locked (or "all package")
 *  place - a string of ascii characters that defines the initial "place" where
 *    the current operation is - this is updated by lockupd() and is a string
 *    is used fr post mortem operations if the utility should quit improperly.
 * Returns (int):
 *  == 0 - failure
 *  != 0 - success
 */

int
lockinst(char *util_name, char *pkg_name, char *place)
{
    int fd, retry_cnt;

    /* assume "initial" if no "place" during processing specified */

    if ((place == (char *)NULL) || (*place == '\0')) {
        place = "initial";
    }

    (void) snprintf(lockpath, sizeof (lockpath),
            "%s/%s", get_PKGADM(), LOCKFILE);

    /* If the exit file is not present, create it. */
    /* LINTED O_CREAT without O_EXCL specified in call to open() */
    if ((fd = open(lockpath, O_RDWR | O_CREAT, 0600)) == -1) {
        progerr(gettext(ERR_MKLOCK), lockpath);
        return (0);
    }

    lock_fd = fd;

    retry_cnt = LOCKRETRY;
    lock_is_applied = 0;

    (void) signal(SIGALRM, do_alarm);
    (void) alarm(LOCKWAIT);

    /*
     * This tries to create the lock LOCKRETRY times waiting LOCKWAIT
     * seconds between retries.
     */
    do {

        if (lockf(fd, F_LOCK, 0)) {
            /*
             * Try to read the status of the last (or current)
             * utility.
             */
            rdlockdata(fd);

            logerr(gettext(MSG_WTFOR), lock_name, lock_pkg);
        } else {    /* This process has the lock. */
            rdlockdata(fd);

            if (lock_state != 0) {
                logerr(gettext(WRN_CLRLOCK), lock_name,
                    lock_pkg, lock_place);
                logerr(gettext(WRN_CLRLOCK1));
            }

            lock_pid = getpid();
            (void) strlcpy(lock_name, (util_name) ?
                util_name : gettext("unknown"), sizeof (lock_name));

            (void) strlcpy(lock_pkg, (pkg_name) ?
                pkg_name : gettext("unknown"), sizeof (lock_pkg));

            (void) wrlockdata(fd, lock_pid, lock_name,
                lock_pkg, place, ST_QUIT);
            lock_is_applied = 1;
            break;
        }
    } while (retry_cnt--);

    (void) signal(SIGALRM, SIG_IGN);

    if (!lock_is_applied) {
        progerr(gettext(ERR_NOLOCK), lockpath);
        return (0);
    }

    return (1);
}

/*
 * This function updates the utility progress data in the lock file. It is
 * used for post mortem operations if the utility should quit improperly.
 */
void
lockupd(char *place)
{
    (void) wrlockdata(lock_fd, lock_pid, lock_name, lock_pkg, place,
            ST_QUIT);
}

/*
 * This clears the governing lock and closes the lock file. If this was
 * called already, it just returns.
 */
void
unlockinst(void)
{
    if (lock_is_applied) {
        (void) wrlockdata(lock_fd, lock_pid, lock_name, lock_pkg,
            "finished", ST_OK);

        /*
         * If close() fails, we can't be sure the lock has been
         * removed, so we assume the worst in case this function is
         * called again.
         */
        if (close(lock_fd) != -1)
            lock_is_applied = 0;
    }
}