/* @(#) $Header: /var/lib/cvsd/repos/CSRG/43BSDReno/contrib/mh/zotnet/mts/lock.c,v 1.1.1.1 2018/04/24 16:12:56 root Exp $ (LBL) */ /* lock.c - universal locking routines */ #ifdef MMDFONLY #define LOCKONLY #endif MMDFONLY #include #ifndef LOCKONLY #include "../h/strings.h" #include "mts.h" #else LOCKONLY #include "strings.h" #ifdef MMDFONLY #include "mmdfonly.h" #include "mts.h" #else not MMDFONLY #include "lockonly.h" #endif not MMDFONLY #endif LOCKONLY #include #include #ifdef SUNOS4 #include #endif #define NOTOK (-1) #define OK 0 #define NULLCP ((char *) 0) #ifdef SYS5 #define index strchr #define rindex strrchr #endif SYS5 #ifndef SIGDECL #ifdef SUNOS4 #define SIGDECL void #else #define SIGDECL int #endif #endif extern int errno; #ifdef LOCKONLY #ifndef MMDFONLY char *lockldir = "/usr/spool/locks"; #endif not MMDFONLY #endif LOCKONLY long time(); static int b_lkopen(), lockit(), f_lkopen(); static void lockname(), timerON(), timerOFF(); /* */ lkopen(file, access) register char *file; register int access; { mts_init ("mts"); switch (lockstyle) { case LOK_UNIX: #ifdef BSD42 return f_lkopen (file, access); #endif BSD42 default: return b_lkopen (file, access); } } /* */ static int b_lkopen(file, access) register char *file; register int access; { register int i, j; long curtime; char curlock[BUFSIZ], tmplock[BUFSIZ]; struct stat st; if (stat (file, &st) == NOTOK) return NOTOK; lockname (curlock, tmplock, file, (int) st.st_dev, (int) st.st_ino); for (i = 0;;) switch (lockit (tmplock, curlock)) { case OK: if ((i = open (file, access)) == NOTOK) { j = errno; (void) unlink (curlock); errno = j; } timerON (curlock, i); return i; case NOTOK: if (stat (curlock, &st) == NOTOK) { if (i++ > 5) return NOTOK; sleep (5); break; } i = 0; (void) time (&curtime); if (curtime < st.st_ctime + 60L) sleep (5); else (void) unlink (curlock); break; } } static int lockit(tmp, file) register char *tmp, *file; { register int fd; if ((fd = creat (tmp, 0400)) == NOTOK) return NOTOK; (void) close (fd); fd = link (tmp, file); (void) unlink (tmp); return (fd != NOTOK ? OK : NOTOK); } /* */ static void lockname(curlock, tmplock, file, dev, ino) register char *curlock, *tmplock, *file; register int dev, ino; { register char *bp, *cp; bp = curlock; if ((cp = rindex (file, '/')) == NULL || *++cp == NULL) cp = file; if (lockldir == NULL || *lockldir == NULL) { if (cp != file) { (void) sprintf (bp, "%.*s", cp - file, file); bp += strlen (bp); } } else { (void) sprintf (bp, "%s/", lockldir); bp += strlen (bp); } switch (lockstyle) { case LOK_BELL: default: (void) sprintf (bp, "%s.lock", cp); break; case LOK_MMDF: (void) sprintf (bp, "LCK%05d.%05d", dev, ino); break; } if (tmplock) { if ((cp = rindex (curlock, '/')) == NULL || *++cp == NULL) (void) strcpy (tmplock, ",LCK.XXXXXX"); else (void) sprintf (tmplock, "%.*s,LCK.XXXXXX", cp - curlock, curlock); (void) unlink (mktemp (tmplock)); } } /* */ #ifdef BSD42 #include #ifndef O_NDELAY #include #endif static int f_lkopen(file, access) register char *file; register int access; { register int fd, i, j; #ifdef sun /* Must force some kind of write access or else lockf() fails */ if (access == 0) access = O_RDWR; #endif for (i = 0; i < 5; i++) { if ((fd = open (file, access | O_NDELAY)) == NOTOK) return NOTOK; #ifndef sun if (flock (fd, LOCK_EX | LOCK_NB) != NOTOK) #else if (lockf (fd, F_TLOCK, 0) != NOTOK) #endif return fd; j = errno; (void) close (fd); sleep (5); } (void) close (fd); errno = j; return NOTOK; } #endif BSD42 /* */ /* ARGSUSED */ lkclose(fd, file) register int fd; register char *file; { char curlock[BUFSIZ]; struct stat st; if (fd == NOTOK) return OK; switch (lockstyle) { case LOK_UNIX: #ifdef BSD42 break; #endif BSD42 default: if (fstat (fd, &st) != NOTOK) { lockname (curlock, NULLCP, file, (int) st.st_dev, (int) st.st_ino); (void) unlink (curlock); timerOFF (fd); } } return (close (fd)); } /* */ FILE * lkfopen(file, mode) register char *file, *mode; { register int fd; register FILE *fp; if ((fd = lkopen (file, strcmp (mode, "r") ? 2 : 0)) == NOTOK) return NULL; if ((fp = fdopen (fd, mode)) == NULL) { (void) close (fd); return NULL; } return fp; } /* ARGSUSED */ lkfclose(fp, file) register FILE *fp; register char *file; { char curlock[BUFSIZ]; struct stat st; if (fp == NULL) return OK; switch (lockstyle) { case LOK_UNIX: #ifdef BSD42 break; #endif BSD42 default: if (fstat (fileno (fp), &st) != NOTOK) { lockname (curlock, NULLCP, file, (int) st.st_dev, (int) st.st_ino); (void) unlink (curlock); } } return (fclose (fp)); } /* */ #include #define NSECS ((unsigned) 20) struct lock { int l_fd; char *l_lock; struct lock *l_next; }; #define NULLP ((struct lock *) 0) static struct lock *l_top = NULLP; /* ARGSUSED */ static SIGDECL alrmser(sig) int sig; { register int j; register char *cp; register struct lock *lp; #ifndef BSD42 (void) signal (SIGALRM, alrmser); #endif BSD42 for (lp = l_top; lp; lp = lp -> l_next) if (*(cp = lp -> l_lock) && (j = creat (cp, 0400)) != NOTOK) (void) close (j); (void) alarm (NSECS); } /* */ static void timerON(lock, fd) char *lock; int fd; { register struct lock *lp; if ((lp = (struct lock *) malloc ((unsigned) (sizeof *lp))) == NULLP) return; /* XXX */ lp -> l_fd = fd; if ((lp -> l_lock = malloc ((unsigned) (strlen (lock) + 1))) == NULLCP) { free ((char *) lp); return; /* XXX */ } (void) strcpy (lp -> l_lock, lock); lp -> l_next = NULLP; if (l_top) lp -> l_next = l_top -> l_next; else { (void) signal (SIGALRM, alrmser);/* perhaps SIGT{STP,TIN,TOU} */ (void) alarm (NSECS); } l_top = lp; } static void timerOFF(fd) int fd; { register struct lock *pp, *lp; (void) alarm (0); if (l_top) { for (pp = lp = l_top; lp; pp = lp, lp = lp -> l_next) if (lp -> l_fd == fd) break; if (lp) { if (lp == l_top) l_top = lp -> l_next; else pp -> l_next = lp -> l_next; free (lp -> l_lock); free ((char *) lp); } } if (l_top) (void) alarm (NSECS); }