/* $NetBSD: lockd_lock.c,v 1.10 2002/07/26 01:00:46 wiz Exp $ */ /* * Copyright (c) 2000 Manuel Bouyer. * * 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. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "lockd_lock.h" #include "lockd.h" /* A set of utilities for managing file locking */ LIST_HEAD(lcklst_head, file_lock); struct lcklst_head lcklst_head = LIST_HEAD_INITIALIZER(lcklst_head); /* struct describing a lock */ struct file_lock { LIST_ENTRY(file_lock) lcklst; fhandle_t filehandle; /* NFS filehandle */ struct sockaddr *addr; struct nlm4_holder client; /* lock holder */ netobj client_cookie; /* cookie sent by the client */ char client_name[128]; int nsm_status; /* status from the remote lock manager */ int status; /* lock status, see below */ int flags; /* lock flags, see lockd_lock.h */ pid_t locker; /* pid of the child process trying to get the lock */ int fd; /* file descriptor for this lock */ }; /* lock status */ #define LKST_LOCKED 1 /* lock is locked */ #define LKST_WAITING 2 /* file is already locked by another host */ #define LKST_PROCESSING 3 /* child is trying to acquire the lock */ #define LKST_DYING 4 /* must dies when we get news from the child */ void lfree __P((struct file_lock *)); enum nlm_stats do_lock __P((struct file_lock *, int)); enum nlm_stats do_unlock __P((struct file_lock *)); void send_granted __P((struct file_lock *, int)); void siglock __P((void)); void sigunlock __P((void)); /* list of hosts we monitor */ LIST_HEAD(hostlst_head, host); struct hostlst_head hostlst_head = LIST_HEAD_INITIALIZER(hostlst_head); /* struct describing a lock */ struct host { LIST_ENTRY(host) hostlst; char name[SM_MAXSTRLEN]; int refcnt; }; void do_mon __P((char *)); /* * testlock(): inform the caller if the requested lock would be granted or not * returns NULL if lock would granted, or pointer to the current nlm4_holder * otherwise. */ struct nlm4_holder * testlock(lock, flags) struct nlm4_lock *lock; int flags; { struct file_lock *fl; fhandle_t filehandle; /* convert lock to a local filehandle */ memcpy(&filehandle, lock->fh.n_bytes, sizeof(filehandle)); siglock(); /* search through the list for lock holder */ for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = LIST_NEXT(fl, lcklst)) { if (fl->status != LKST_LOCKED) continue; if (memcmp(&fl->filehandle, &filehandle, sizeof(filehandle))) continue; /* got it ! */ syslog(LOG_DEBUG, "test for %s: found lock held by %s", lock->caller_name, fl->client_name); sigunlock(); return (&fl->client); } /* not found */ sigunlock(); syslog(LOG_DEBUG, "test for %s: no lock found", lock->caller_name); return NULL; } /* * getlock: try to acquire the lock. * If file is already locked and we can sleep, put the lock in the list with * status LKST_WAITING; it'll be processed later. * Otherwise try to lock. If we're allowed to block, fork a child which * will do the blocking lock. */ enum nlm_stats getlock(lckarg, rqstp, flags) nlm4_lockargs * lckarg; struct svc_req *rqstp; int flags; { struct file_lock *fl, *newfl; enum nlm_stats retval; if (grace_expired == 0 && lckarg->reclaim == 0) return (flags & LOCK_V4) ? nlm4_denied_grace_period : nlm_denied_grace_period; /* allocate new file_lock for this request */ newfl = malloc(sizeof(struct file_lock)); if (newfl == NULL) { syslog(LOG_NOTICE, "malloc failed: %s", strerror(errno)); /* failed */ return (flags & LOCK_V4) ? nlm4_denied_nolock : nlm_denied_nolocks; } if (lckarg->alock.fh.n_len != sizeof(fhandle_t)) { syslog(LOG_DEBUG, "received fhandle size %d, local size %d", lckarg->alock.fh.n_len, (int)sizeof(fhandle_t)); } memcpy(&newfl->filehandle, lckarg->alock.fh.n_bytes, sizeof(fhandle_t)); newfl->addr = (struct sockaddr *)svc_getrpccaller(rqstp->rq_xprt)->buf; newfl->client.exclusive = lckarg->exclusive; newfl->client.svid = lckarg->alock.svid; newfl->client.oh.n_bytes = malloc(lckarg->alock.oh.n_len); if (newfl->client.oh.n_bytes == NULL) { syslog(LOG_NOTICE, "malloc failed: %s", strerror(errno)); free(newfl); return (flags & LOCK_V4) ? nlm4_denied_nolock : nlm_denied_nolocks; } newfl->client.oh.n_len = lckarg->alock.oh.n_len; memcpy(newfl->client.oh.n_bytes, lckarg->alock.oh.n_bytes, lckarg->alock.oh.n_len); newfl->client.l_offset = lckarg->alock.l_offset; newfl->client.l_len = lckarg->alock.l_len; newfl->client_cookie.n_len = lckarg->cookie.n_len; newfl->client_cookie.n_bytes = malloc(lckarg->cookie.n_len); if (newfl->client_cookie.n_bytes == NULL) { syslog(LOG_NOTICE, "malloc failed: %s", strerror(errno)); free(newfl->client.oh.n_bytes); free(newfl); return (flags & LOCK_V4) ? nlm4_denied_nolock : nlm_denied_nolocks; } memcpy(newfl->client_cookie.n_bytes, lckarg->cookie.n_bytes, lckarg->cookie.n_len); strncpy(newfl->client_name, lckarg->alock.caller_name, 128); newfl->nsm_status = lckarg->state; newfl->status = 0; newfl->flags = flags; siglock(); /* look for a lock rq from this host for this fh */ for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = LIST_NEXT(fl, lcklst)) { if (memcmp(&newfl->filehandle, &fl->filehandle, sizeof(fhandle_t)) == 0) { if (strcmp(newfl->client_name, fl->client_name) == 0 && newfl->client.svid == fl->client.svid) { /* already locked by this host ??? */ sigunlock(); syslog(LOG_NOTICE, "duplicate lock from %s", newfl->client_name); lfree(newfl); switch(fl->status) { case LKST_LOCKED: return (flags & LOCK_V4) ? nlm4_granted : nlm_granted; case LKST_WAITING: case LKST_PROCESSING: return (flags & LOCK_V4) ? nlm4_blocked : nlm_blocked; case LKST_DYING: return (flags & LOCK_V4) ? nlm4_denied : nlm_denied; default: syslog(LOG_NOTICE, "bad status %d", fl->status); return (flags & LOCK_V4) ? nlm4_failed : nlm_denied; } } /* * We already have a lock for this file. Put this one * in waiting state if allowed to block */ if (lckarg->block) { syslog(LOG_DEBUG, "lock from %s: already " "locked, waiting", lckarg->alock.caller_name); newfl->status = LKST_WAITING; LIST_INSERT_HEAD(&lcklst_head, newfl, lcklst); do_mon(lckarg->alock.caller_name); sigunlock(); return (flags & LOCK_V4) ? nlm4_blocked : nlm_blocked; } else { sigunlock(); syslog(LOG_DEBUG, "lock from %s: already " "locked, failed", lckarg->alock.caller_name); lfree(newfl); return (flags & LOCK_V4) ? nlm4_denied : nlm_denied; } } } /* no entry for this file yet; add to list */ LIST_INSERT_HEAD(&lcklst_head, newfl, lcklst); /* do the lock */ retval = do_lock(newfl, lckarg->block); switch (retval) { case nlm4_granted: /* case nlm_granted: is the same as nlm4_granted */ case nlm4_blocked: /* case nlm_blocked: is the same as nlm4_blocked */ do_mon(lckarg->alock.caller_name); break; default: lfree(newfl); break; } sigunlock(); return retval; } /* unlock a filehandle */ enum nlm_stats unlock(lck, flags) nlm4_lock *lck; int flags; { struct file_lock *fl; fhandle_t filehandle; int err = (flags & LOCK_V4) ? nlm4_granted : nlm_granted; memcpy(&filehandle, lck->fh.n_bytes, sizeof(fhandle_t)); siglock(); for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = LIST_NEXT(fl, lcklst)) { if (strcmp(fl->client_name, lck->caller_name) || memcmp(&filehandle, &fl->filehandle, sizeof(fhandle_t)) || fl->client.oh.n_len != lck->oh.n_len || memcmp(fl->client.oh.n_bytes, lck->oh.n_bytes, fl->client.oh.n_len) != 0 || fl->client.svid != lck->svid) continue; /* Got it, unlock and remove from the queue */ syslog(LOG_DEBUG, "unlock from %s: found struct, status %d", lck->caller_name, fl->status); switch (fl->status) { case LKST_LOCKED: err = do_unlock(fl); break; case LKST_WAITING: /* remove from the list */ LIST_REMOVE(fl, lcklst); lfree(fl); break; case LKST_PROCESSING: /* * being handled by a child; will clean up * when the child exits */ fl->status = LKST_DYING; break; case LKST_DYING: /* nothing to do */ break; default: syslog(LOG_NOTICE, "unknow status %d for %s", fl->status, fl->client_name); } sigunlock(); return err; } sigunlock(); /* didn't find a matching entry; log anyway */ syslog(LOG_NOTICE, "no matching entry for %s", lck->caller_name); return (flags & LOCK_V4) ? nlm4_granted : nlm_granted; } void lfree(fl) struct file_lock *fl; { free(fl->client.oh.n_bytes); free(fl->client_cookie.n_bytes); free(fl); } void sigchild_handler(sig) int sig; { int status; pid_t pid; struct file_lock *fl; while (1) { pid = wait4(-1, &status, WNOHANG, NULL); if (pid == -1) { if (errno != ECHILD) syslog(LOG_NOTICE, "wait failed: %s", strerror(errno)); else syslog(LOG_DEBUG, "wait failed: %s", strerror(errno)); return; } if (pid == 0) { /* no more child to handle yet */ return; } /* * if we're here we have a child that exited * Find the associated file_lock. */ for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = LIST_NEXT(fl, lcklst)) { if (pid == fl->locker) break; } if (pid != fl->locker) { syslog(LOG_NOTICE, "unknow child %d", pid); } else { if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { syslog(LOG_NOTICE, "child %d failed", pid); /* * can't do much here; we can't reply * anything but OK for blocked locks * Eventually the client will time out * and retry. */ do_unlock(fl); return; } /* check lock status */ syslog(LOG_DEBUG, "processing child %d, status %d", pid, fl->status); switch(fl->status) { case LKST_PROCESSING: fl->status = LKST_LOCKED; send_granted(fl, (fl->flags & LOCK_V4) ? nlm4_granted : nlm_granted); break; case LKST_DYING: do_unlock(fl); break; default: syslog(LOG_NOTICE, "bad lock status (%d) for" " child %d", fl->status, pid); } } } } /* * * try to acquire the lock described by fl. Eventually fork a child to do a * blocking lock if allowed and required. */ enum nlm_stats do_lock(fl, block) struct file_lock *fl; int block; { int lflags, error; struct stat st; fl->fd = fhopen(&fl->filehandle, O_RDWR); if (fl->fd < 0) { switch (errno) { case ESTALE: error = nlm4_stale_fh; break; case EROFS: error = nlm4_rofs; break; default: error = nlm4_failed; } if ((fl->flags & LOCK_V4) == 0) error = nlm_denied; syslog(LOG_NOTICE, "fhopen failed (from %s): %s", fl->client_name, strerror(errno)); LIST_REMOVE(fl, lcklst); return error;; } if (fstat(fl->fd, &st) < 0) { syslog(LOG_NOTICE, "fstat failed (from %s): %s", fl->client_name, strerror(errno)); } syslog(LOG_DEBUG, "lock from %s for file%s%s: dev %d ino %d (uid %d), " "flags %d", fl->client_name, fl->client.exclusive ? " (exclusive)":"", block ? " (block)":"", st.st_dev, st.st_ino, st.st_uid, fl->flags); lflags = LOCK_NB; if (fl->client.exclusive == 0) lflags |= LOCK_SH; else lflags |= LOCK_EX; error = flock(fl->fd, lflags); if (error != 0 && errno == EAGAIN && block) { switch (fl->locker = fork()) { case -1: /* fork failed */ syslog(LOG_NOTICE, "fork failed: %s", strerror(errno)); LIST_REMOVE(fl, lcklst); close(fl->fd); return (fl->flags & LOCK_V4) ? nlm4_denied_nolock : nlm_denied_nolocks; case 0: /* * Attempt a blocking lock. Will have to call * NLM_GRANTED later. */ setproctitle("%s", fl->client_name); lflags &= ~LOCK_NB; if(flock(fl->fd, lflags) != 0) { syslog(LOG_NOTICE, "flock failed: %s", strerror(errno)); exit(1); } /* lock granted */ exit(0); default: syslog(LOG_DEBUG, "lock request from %s: forked %d", fl->client_name, fl->locker); fl->status = LKST_PROCESSING; return (fl->flags & LOCK_V4) ? nlm4_blocked : nlm_blocked; } } /* non block case */ if (error != 0) { switch (errno) { case EAGAIN: error = nlm4_denied; break; case ESTALE: error = nlm4_stale_fh; break; case EROFS: error = nlm4_rofs; break; default: error = nlm4_failed; } if ((fl->flags & LOCK_V4) == 0) error = nlm_denied; if (errno != EAGAIN) syslog(LOG_NOTICE, "flock for %s failed: %s", fl->client_name, strerror(errno)); else syslog(LOG_DEBUG, "flock for %s failed: %s", fl->client_name, strerror(errno)); LIST_REMOVE(fl, lcklst); close(fl->fd); return error; } fl->status = LKST_LOCKED; return (fl->flags & LOCK_V4) ? nlm4_granted : nlm_granted; } void send_granted(fl, opcode) struct file_lock *fl; int opcode; { CLIENT *cli; static char dummy; struct timeval timeo; int success; static struct nlm_res retval; static struct nlm4_res retval4; cli = get_client(fl->addr, (fl->flags & LOCK_V4) ? NLM_VERS4 : NLM_VERS); if (cli == NULL) { syslog(LOG_NOTICE, "failed to get CLIENT for %s", fl->client_name); /* * We fail to notify remote that the lock has been granted. * The client will timeout and retry, the lock will be * granted at this time. */ return; } timeo.tv_sec = 0; timeo.tv_usec = (fl->flags & LOCK_ASYNC) ? 0 : 500000; /* 0.5s */ if (fl->flags & LOCK_V4) { static nlm4_testargs res; res.cookie = fl->client_cookie; res.exclusive = fl->client.exclusive; res.alock.caller_name = fl->client_name; res.alock.fh.n_len = sizeof(fhandle_t); res.alock.fh.n_bytes = (char*)&fl->filehandle; res.alock.oh = fl->client.oh; res.alock.svid = fl->client.svid; res.alock.l_offset = fl->client.l_offset; res.alock.l_len = fl->client.l_len; syslog(LOG_DEBUG, "sending v4 reply%s", (fl->flags & LOCK_ASYNC) ? " (async)":""); if (fl->flags & LOCK_ASYNC) { success = clnt_call(cli, NLM4_GRANTED_MSG, xdr_nlm4_testargs, &res, xdr_void, &dummy, timeo); } else { success = clnt_call(cli, NLM4_GRANTED, xdr_nlm4_testargs, &res, xdr_nlm4_res, &retval4, timeo); } } else { static nlm_testargs res; res.cookie = fl->client_cookie; res.exclusive = fl->client.exclusive; res.alock.caller_name = fl->client_name; res.alock.fh.n_len = sizeof(fhandle_t); res.alock.fh.n_bytes = (char*)&fl->filehandle; res.alock.oh = fl->client.oh; res.alock.svid = fl->client.svid; res.alock.l_offset = fl->client.l_offset; res.alock.l_len = fl->client.l_len; syslog(LOG_DEBUG, "sending v1 reply%s", (fl->flags & LOCK_ASYNC) ? " (async)":""); if (fl->flags & LOCK_ASYNC) { success = clnt_call(cli, NLM_GRANTED_MSG, xdr_nlm_testargs, &res, xdr_void, &dummy, timeo); } else { success = clnt_call(cli, NLM_GRANTED, xdr_nlm_testargs, &res, xdr_nlm_res, &retval, timeo); } } if (debug_level > 2) syslog(LOG_DEBUG, "clnt_call returns %d(%s) for granted", success, clnt_sperrno(success)); } enum nlm_stats do_unlock(rfl) struct file_lock *rfl; { struct file_lock *fl; int error; int lockst; /* unlock the file: closing is enough ! */ if (close(rfl->fd) < 0) { if (errno == ESTALE) error = nlm4_stale_fh; else error = nlm4_failed; if ((fl->flags & LOCK_V4) == 0) error = nlm_denied; syslog(LOG_NOTICE, "close failed (from %s): %s", rfl->client_name, strerror(errno)); } else { error = (fl->flags & LOCK_V4) ? nlm4_granted : nlm_granted; } LIST_REMOVE(rfl, lcklst); /* process the next LKST_WAITING lock request for this fh */ for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = LIST_NEXT(fl, lcklst)) { if (fl->status != LKST_WAITING || memcmp(&rfl->filehandle, &fl->filehandle, sizeof(fhandle_t)) != 0) continue; lockst = do_lock(fl, 1); /* If it's LKST_WAITING we can block */ switch (lockst) { case nlm4_granted: /* case nlm_granted: same as nlm4_granted */ send_granted(fl, (fl->flags & LOCK_V4) ? nlm4_granted : nlm_granted); break; case nlm4_blocked: /* case nlm_blocked: same as nlm4_blocked */ break; default: lfree(fl); break; } break; } lfree(rfl); return error; } void siglock() { sigset_t block; sigemptyset(&block); sigaddset(&block, SIGCHLD); if (sigprocmask(SIG_BLOCK, &block, NULL) < 0) { syslog(LOG_WARNING, "siglock failed: %s", strerror(errno)); } } void sigunlock() { sigset_t block; sigemptyset(&block); sigaddset(&block, SIGCHLD); if (sigprocmask(SIG_UNBLOCK, &block, NULL) < 0) { syslog(LOG_WARNING, "sigunlock failed: %s", strerror(errno)); } } /* monitor a host through rpc.statd, and keep a ref count */ void do_mon(hostname) char *hostname; { struct host *hp; struct mon my_mon; struct sm_stat_res res; int retval; for (hp = LIST_FIRST(&hostlst_head); hp != NULL; hp = LIST_NEXT(hp, hostlst)) { if (strcmp(hostname, hp->name) == 0) { /* already monitored, just bump refcnt */ hp->refcnt++; return; } } /* not found, have to create an entry for it */ hp = malloc(sizeof(struct host)); strncpy(hp->name, hostname, SM_MAXSTRLEN); hp->refcnt = 1; syslog(LOG_DEBUG, "monitoring host %s", hostname); memset(&my_mon, 0, sizeof(my_mon)); my_mon.mon_id.mon_name = hp->name; my_mon.mon_id.my_id.my_name = "localhost"; my_mon.mon_id.my_id.my_prog = NLM_PROG; my_mon.mon_id.my_id.my_vers = NLM_SM; my_mon.mon_id.my_id.my_proc = NLM_SM_NOTIFY; if ((retval = callrpc("localhost", SM_PROG, SM_VERS, SM_MON, xdr_mon, (char*)&my_mon, xdr_sm_stat_res, (char*)&res)) != 0) { syslog(LOG_WARNING, "rpc to statd failed: %s", clnt_sperrno((enum clnt_stat)retval)); free(hp); return; } if (res.res_stat == stat_fail) { syslog(LOG_WARNING, "statd failed"); free(hp); return; } LIST_INSERT_HEAD(&hostlst_head, hp, hostlst); } void notify(hostname, state) char *hostname; int state; { struct file_lock *fl, *next_fl; int err; syslog(LOG_DEBUG, "notify from %s, new state %d", hostname, state); /* search all lock for this host; if status changed, release the lock */ siglock(); for (fl = LIST_FIRST(&lcklst_head); fl != NULL; fl = next_fl) { next_fl = LIST_NEXT(fl, lcklst); if (strcmp(hostname, fl->client_name) == 0 && fl->nsm_status != state) { syslog(LOG_DEBUG, "state %d, nsm_state %d, unlocking", fl->status, fl->nsm_status); switch(fl->status) { case LKST_LOCKED: err = do_unlock(fl); if (err != nlm_granted) syslog(LOG_DEBUG, "notify: unlock failed for %s (%d)", hostname, err); break; case LKST_WAITING: LIST_REMOVE(fl, lcklst); lfree(fl); break; case LKST_PROCESSING: fl->status = LKST_DYING; break; case LKST_DYING: break; default: syslog(LOG_NOTICE, "unknow status %d for %s", fl->status, fl->client_name); } } } sigunlock(); }