1/*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 1997,2008 Oracle. All rights reserved. 5 * 6 * $Id: os_flock.c,v 12.16 2008/01/08 20:58:43 bostic Exp $ 7 */ 8 9#include "db_config.h" 10 11#include "db_int.h" 12 13/* 14 * __os_fdlock -- 15 * Acquire/release a lock on a byte in a file. 16 * 17 * PUBLIC: int __os_fdlock __P((ENV *, DB_FH *, off_t, int, int)); 18 */ 19int 20__os_fdlock(env, fhp, offset, acquire, nowait) 21 ENV *env; 22 DB_FH *fhp; 23 int acquire, nowait; 24 off_t offset; 25{ 26#ifdef HAVE_FCNTL 27 DB_ENV *dbenv; 28 struct flock fl; 29 int ret, t_ret; 30 31 dbenv = env == NULL ? NULL : env->dbenv; 32 33 DB_ASSERT(env, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1); 34 35 if (dbenv != NULL && FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS_ALL)) 36 __db_msg(env, 37 "fileops: flock %s %s offset %lu", 38 fhp->name, acquire ? "acquire": "release", (u_long)offset); 39 40 fl.l_start = offset; 41 fl.l_len = 1; 42 fl.l_type = acquire ? F_WRLCK : F_UNLCK; 43 fl.l_whence = SEEK_SET; 44 45 RETRY_CHK_EINTR_ONLY( 46 (fcntl(fhp->fd, nowait ? F_SETLK : F_SETLKW, &fl)), ret); 47 48 if (ret == 0) 49 return (0); 50 51 if ((t_ret = __os_posix_err(ret)) != EACCES && t_ret != EAGAIN) 52 __db_syserr(env, ret, "fcntl"); 53 return (t_ret); 54#else 55 COMPQUIET(fhp, NULL); 56 COMPQUIET(acquire, 0); 57 COMPQUIET(nowait, 0); 58 COMPQUIET(offset, 0); 59 __db_syserr(env, DB_OPNOTSUP, "advisory file locking unavailable"); 60 return (DB_OPNOTSUP); 61#endif 62} 63