/********************************************************************** * Copyright (c) Digital Equipment Corporation 1984, 1985, 1986. * * All Rights Reserved. * * Reference "/usr/src/COPYRIGHT" for applicable restrictions. * **********************************************************************/ static char Sccsid[] = "@(#)ulockf.c 3.0 4/22/86"; /******* * ulockf(file, atime) * char *file; * time_t atime; * * ulockf - this routine will create a lock file (file). * If one already exists, the create time is checked for * older than the age time (atime). * If it is older, an attempt will be made to unlink it * and create a new one. * * return codes: 0 | FAIL */ /******************* * Mods: * decvax!larry - decrement count of lock files when remove lock * and make associated changes that make this possible * * - use full path name of lock (does not assume in * spool directory like before) *******************/ #include "uucp.h" #include <sys/types.h> #include <sys/stat.h> #include <time.h> #include <errno.h> extern int errno; extern time_t time(); /* File mode for lock files */ #define LCKMODE 0444 ulockf(file, atime) char *file; time_t atime; { struct stat stbuf; time_t ptime; int ret; static int pid = -1; static char tempfile[MAXFULLNAME]; if (pid < 0) { pid = getpid(); sprintf(tempfile, "%s/LTMP.%d", SPOOL, pid); } if (onelock(pid, tempfile, file) == -1) { /* lock file exists */ /* get status to check age of the lock file */ ret = stat(file, &stbuf); if (ret != -1) { time(&ptime); if ((ptime - stbuf.st_ctime) < atime) { /* file not old enough to delete */ DEBUG(8,"lock not old enough to delete: %s\n", file); return(FAIL); } } if ((ret = unlink(file))) DEBUG(4, "ulockf, could not unlink, errno=%d\n", errno); ret = onelock(pid, tempfile, file); if (ret != 0) { /* unlinked old lock file but could not create new one*/ DEBUG(8,"could not create new lock %s\n", file); return(FAIL); } } stlock(file); return(0); } #define MAXLOCKS 10 /* maximum number of lock files */ char *Lockfile[MAXLOCKS]; int Nlocks = 0; /*** * stlock(name) put name in list of lock files * char *name; * * return codes: none */ stlock(name) char *name; { char *p; int i; for (i = 0; i < MAXLOCKS; i++) { if (Lockfile[i] == NULL) break; } ASSERT(++Nlocks < MAXLOCKS, "TOO MANY LOCKS", "", Nlocks); p = calloc((unsigned)(strlen(name)+1), sizeof (char)); ASSERT(p != NULL, "CAN NOT ALLOCATE FOR", name, 0); strcpy(p, name); Lockfile[i] = p; return; } /*** * rmlock(name) remove all lock files in list * char *name; or name * * return codes: none */ rmlock(name) char *name; { register int i; int ret; for (i = 0; i < MAXLOCKS; i++) { if (Lockfile[i] == NULL) continue; if (name == NULL || strcmp(name, Lockfile[i]) == SAME) { Nlocks--; ret = unlink(Lockfile[i]); /* some locks may be removed by other daemons ASSERT_NOFAIL(ret == 0, "could not unlink lock", Lockfile[i], errno); */ free(Lockfile[i]); Lockfile[i] = NULL; } } return; } /* this stuff from pjw */ /* /usr/pjw/bin/recover - check pids to remove unnecessary locks */ /* isalock(name) returns 0 if the name is a lock */ /* unlock(name) unlocks name if it is a lock*/ /* onelock(pid,tempfile,name) makes lock a name on behalf of pid. Tempfile must be in the same file system as name. */ /* lock(pid,tempfile,names) either locks all the names or none of them */ isalock(name) char *name; { struct stat xstat; if(stat(name,&xstat)<0) return(0); if(xstat.st_size!=sizeof(int)) return(0); return(1); } unlock(name) char *name; { if(isalock(name)) return(unlink(name)); else return(-1); } onelock(pid,tempfile,name) char *tempfile,*name; { int fd; DEBUG(9, "in onelock, name=%s\n",name); fd=creat(tempfile,LCKMODE); if(fd<0) { DEBUG(9, "could not create tempfile-errno=%d\n", errno); return(-1); } write(fd,(char *) &pid,sizeof(int)); close(fd); if(link(tempfile,name)<0) { DEBUG(9, "in onelock, errno=%d\n",errno); unlink(tempfile); return(-1); } unlink(tempfile); chmod(name, 0644); return(0); } lock(pid,tempfile,names) char *tempfile,**names; { int i,j; for(i=0;names[i]!=0;i++) { if(onelock(pid,tempfile,names[i])==0) continue; for(j=0;j<i;j++) unlink(names[j]); return(-1); } return(0); } #define LOCKPRE "LCK." /*** * delock(s) remove a lock file * char *s; * * return codes: 0 | FAIL */ delock(s) char *s; { char ln[70]; sprintf(ln, "%s/%s.%s", SPOOL, LOCKPRE, s); rmlock(ln); } /*** * mlock(sys) create system lock * char *sys; * * return codes: 0 | FAIL */ mlock(sys) char *sys; { char lname[70]; sprintf(lname, "%s/%s.%s", SPOOL, LOCKPRE, sys); return(ulockf(lname, (time_t) SLCKTIME ) < 0 ? FAIL : 0); } /*** * ultouch() update 'change' time for lock files * * -- mod by rti!trt -- * Only update ctime, not mtime or atime. * The 'chmod' method permits cu(I)-like programs * to determine how long uucp has been on the line. * The old "change access, mod, and change time" method * can be had by defining OLDTOUCH * * return code - none */ ultouch() { time_t time(); static time_t lasttouch = 0; register int i; struct ut { time_t actime; time_t modtime; } ut; ut.actime = time(&ut.modtime); /* Do not waste time touching locking files too often */ if ((ut.actime - lasttouch) < 60) return; lasttouch = ut.actime; DEBUG(4, "ultouch\n", 0); for (i = 0; i < Nlocks; i++) { if (Lockfile[i] == NULL) continue; #ifdef OLDTOUCH utime(Lockfile[i], &ut); #else chmod(Lockfile[i], LCKMODE); #endif } return; }