/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (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 1997 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ /* All Rights Reserved */ #pragma ident "%Z%%M% %I% %E% SMI" #include "uucp.h" #include /* #include */ /* #include */ static struct stat _st_buf; static char lockname[BUFSIZ]; #ifdef V7 #define O_RDONLY 0 #endif static void stlock(); static int onelock(); /* * make a lock file with given 'name' * If one already exists, send a signal 0 to the process--if * it fails, then unlink it and make a new one. * * input: * name - name of the lock file to make * * return: * 0 -> success * FAIL -> failure */ GLOBAL int mklock(name) register char *name; { static char pid[SIZEOFPID+2] = { '\0' }; /* +2 for '\n' and NULL */ static char tempfile[MAXNAMESIZE]; #ifdef V8 char *cp; #endif if (pid[0] == '\0') { (void) sprintf(pid, "%*ld\n", SIZEOFPID, (long) getpid()); (void) sprintf(tempfile, "%s/LTMP.%ld", X_LOCKDIR, (long) getpid()); } #ifdef V8 /* this wouldn't be a problem if we used lock directories */ /* some day the truncation of system names will bite us */ cp = rindex(name, '/'); if (cp++ != CNULL) if (strlen(cp) > MAXBASENAME) *(cp+MAXBASENAME) = NULLCHAR; #endif /* V8 */ if (onelock(pid, tempfile, name) == -1) { (void) unlink(tempfile); if (cklock(name)) return(FAIL); else { if (onelock(pid, tempfile, name)) { (void) unlink(tempfile); DEBUG(4,"ulockf failed in onelock()\n%s", ""); return(FAIL); } } } stlock(name); return(0); } /* * check to see if the lock file exists and is still active * - use kill(pid,0) * * return: * 0 -> success (lock file removed - no longer active * FAIL -> lock file still active */ GLOBAL int cklock(name) register char *name; { register int ret; pid_t lpid = -1; char alpid[SIZEOFPID+2]; /* +2 for '\n' and NULL */ int fd; fd = open(name, O_RDONLY); DEBUG(4, "ulockf name %s\n", name); if (fd == -1) { if (errno == ENOENT) /* file does not exist -- OK */ return(0); DEBUG(4,"Lock File--can't read (errno %d) --remove it!\n", errno); goto unlk; } ret = read(fd, (char *) alpid, SIZEOFPID+1); /* +1 for '\n' */ (void) close(fd); if (ret != (SIZEOFPID+1)) { DEBUG(4, "Lock File--bad format--remove it!\n%s", ""); goto unlk; } lpid = (pid_t) strtol(alpid, (char **) NULL, 10); if ((ret=kill(lpid, 0)) == 0 || errno == EPERM) { DEBUG(4, "Lock File--process still active--not removed\n%s", ""); return(FAIL); } else { /* process no longer active */ DEBUG(4, "kill pid (%ld), ", (long) lpid); DEBUG(4, "returned %d", ret); DEBUG(4, "--ok to remove lock file (%s)\n", name); } unlk: if (unlink(name) != 0) { DEBUG(4,"ulockf failed in unlink()\n%s", ""); return(FAIL); } return(0); } #define MAXLOCKS 10 /* maximum number of lock files */ static char *Lockfile[MAXLOCKS]; GLOBAL int Nlocks = 0; /* * put name in list of lock files * return: * none */ static void stlock(name) char *name; { register int i; char *p; for (i = 0; i < Nlocks; i++) { if (Lockfile[i] == NULL) break; } ASSERT(i < MAXLOCKS, "TOO MANY LOCKS", "", i); if (i >= Nlocks) i = Nlocks++; p = (char*) calloc((unsigned) strlen(name) + 1, sizeof (char)); ASSERT(p != NULL, "CAN NOT ALLOCATE FOR", name, 0); (void) strcpy(p, name); Lockfile[i] = p; return; } /* * remove the named lock. If named lock is NULL, * then remove all locks currently in list. * return: * none */ GLOBAL void rmlock(name) register char *name; { register int i; #ifdef V8 char *cp; cp = rindex(name, '/'); if (cp++ != CNULL) if (strlen(cp) > MAXBASENAME) *(cp+MAXBASENAME) = NULLCHAR; #endif /* V8 */ for (i = 0; i < Nlocks; i++) { if (Lockfile[i] == NULL) continue; if (name == NULL || EQUALS(name, Lockfile[i])) { (void) unlink(Lockfile[i]); free(Lockfile[i]); Lockfile[i] = NULL; } } return; } /* * remove a lock file * * Parameters: * pre - Path and first part of file name of the lock file to be * removed. * s - The suffix part of the lock file. The name of the lock file * will be derrived by concatenating pre, a period, and s. * * return: * none */ GLOBAL void delock(pre, s) char * pre; char *s; { char ln[MAXNAMESIZE]; (void) sprintf(ln, "%s.%s", pre, s); BASENAME(ln, '/')[MAXBASENAME] = '\0'; rmlock(ln); return; } /* * create lock file * * Parameters: * pre - Path and first part of file name of the lock file to be * created. * name - The suffix part of the lock file. The name of the lock file * will be derrived by concatenating pre, a period, and name. * * return: * 0 -> success * FAIL -> failure */ GLOBAL int umlock(pre, name) char * pre; char *name; { char lname[MAXNAMESIZE]; /* * if name has a '/' in it, then it's a device name and it's * not in /dev (i.e., it's a remotely-mounted device or it's * in a subdirectory of /dev). in either case, creating our normal * lockfile (/var/spool/locks/LCK..) is going to bomb if * is "/remote/dev/term/14" or "/dev/net/foo/clone", so never * mind. since we're using advisory filelocks on the devices * themselves, it'll be safe. * * of course, programs and people who are used to looking at the * lockfiles to find out what's going on are going to be a trifle * misled. we really need to re-consider the lockfile naming structure * to accomodate devices in directories other than /dev ... maybe in * the next release. */ if ( strchr(name, '/') != NULL ) return(0); (void) sprintf(lname, "%s.%s", pre, BASENAME(name, '/')); BASENAME(lname, '/')[MAXBASENAME] = '\0'; return(mklock(lname)); } /* * makes a lock on behalf of pid. * input: * pid - process id * tempfile - name of a temporary in the same file system * name - lock file name (full path name) * return: * -1 - failed * 0 - lock made successfully */ static int onelock(pid,tempfile,name) char *pid; char *tempfile, *name; { register int fd; char cb[100]; fd=creat(tempfile, (mode_t) 0444); if(fd < 0){ (void) sprintf(cb, "%s %s %d",tempfile, name, errno); logent("ULOCKC", cb); if((errno == EMFILE) || (errno == ENFILE)) (void) unlink(tempfile); return(-1); } /* +1 for '\n' */ if (write(fd, pid, SIZEOFPID+1) != (SIZEOFPID+1)) { (void) sprintf(cb, "%s %s %d",tempfile, name, errno); logent("ULOCKW", cb); (void) unlink(tempfile); return (-1); } (void) chmod(tempfile, (mode_t) 0444); (void) chown(tempfile, UUCPUID, UUCPGID); (void) close(fd); if(link(tempfile,name)<0){ DEBUG(4, "%s: ", sys_errlist[errno]); DEBUG(4, "link(%s, ", tempfile); DEBUG(4, "%s)\n", name); if(unlink(tempfile)< 0){ (void) sprintf(cb, "ULK err %s %d", tempfile, errno); logent("ULOCKLNK", cb); } return(-1); } if(unlink(tempfile)<0){ (void) sprintf(cb, "%s %d",tempfile,errno); logent("ULOCKF", cb); } return(0); } /* * fd_mklock(fd) - lock the device indicated by fd if possible * * return - * SUCCESS - this process now has the fd locked * FAIL - this process was not able to lock the fd */ GLOBAL int fd_mklock(fd) int fd; { int tries = 0; if ( fstat(fd, &_st_buf) != 0 ) return(FAIL); (void) sprintf(lockname, "%s.%3.3lu.%3.3lu.%3.3lu", L_LOCK, (unsigned long) major(_st_buf.st_dev), (unsigned long) major(_st_buf.st_rdev), (unsigned long) minor(_st_buf.st_rdev)); if ( mklock(lockname) == FAIL ) return(FAIL); while ( lockf(fd, F_TLOCK, 0L) != 0 ) { DEBUG(7, "fd_mklock: lockf returns %d\n", errno); if ( (++tries >= MAX_LOCKTRY) || (errno != EAGAIN) ) { rmlock(lockname); logent("fd_mklock","lockf failed"); return(FAIL); } sleep(2); } DEBUG(7, "fd_mklock: ok\n%s", ""); return(SUCCESS); } /* * fn_cklock(name) - determine if the device indicated by name is locked * * return - * SUCCESS - the name is not locked * FAIL - the name is locked by another process */ GLOBAL int fn_cklock(name) char *name; { /* we temporarily use lockname to hold full path name */ (void) sprintf(lockname, "%s%s", (*name == '/' ? "" : "/dev/"), name); if ( stat(lockname, &_st_buf) != 0 ) return(FAIL); (void) sprintf(lockname, "%s.%3.3lu.%3.3lu.%3.3lu", L_LOCK, (unsigned long) major(_st_buf.st_dev), (unsigned long) major(_st_buf.st_rdev), (unsigned long) minor(_st_buf.st_rdev)); return(cklock(lockname)); } /* * fd_cklock(fd) - determine if the device indicated by fd is locked * * return - * SUCCESS - the fd is not locked * FAIL - the fd is locked by another process */ GLOBAL int fd_cklock(fd) int fd; { if ( fstat(fd, &_st_buf) != 0 ) return(FAIL); (void) sprintf(lockname, "%s.%3.3lu.%3.3lu.%3.3lu", L_LOCK, (unsigned long) major(_st_buf.st_dev), (unsigned long) major(_st_buf.st_rdev), (unsigned long) minor(_st_buf.st_rdev)); if ( cklock(lockname) == FAIL ) return(FAIL); else return( lockf(fd, F_TEST, 0L) ); } /* * remove the locks associated with the device file descriptor * * return - * SUCCESS - both BNU lock file and advisory locks removed * FAIL - */ GLOBAL void fd_rmlock(fd) int fd; { if ( fstat(fd, &_st_buf) == 0 ) { (void) sprintf(lockname, "%s.%3.3lu.%3.3lu.%3.3lu", L_LOCK, (unsigned long) major(_st_buf.st_dev), (unsigned long) major(_st_buf.st_rdev), (unsigned long) minor(_st_buf.st_rdev)); rmlock(lockname); } (void) lockf(fd, F_ULOCK, 0L); return; } #ifdef BSD4_2 #include static int lockf(fd, cmd, size) int fd, cmd; long size; { int ret; if (size != 0) { errno = EINVAL; return (-1); } switch (cmd) { case F_LOCK: cmd = LOCK_EX; break; case F_TLOCK: cmd = LOCK_EX|LOCK_NB; break; case F_ULOCK: cmd = LOCK_UN; break; case F_TEST: if (flock(fd, LOCK_EX|LOCK_NB) == 0 && flock(fd, LOCK_UN) == 0) return (0); errno = EAGAIN; return (-1); default: errno = EINVAL; return (-1); } ret = flock(fd, cmd); if (ret < 0 && errno == EWOULDBLOCK) errno = EAGAIN; } #endif /* BSD4_2 */