Import BSDDB 4.7.25 (as of svn r89086)

os/os_flock.c

@@ -0,0 +1,62 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1997,2008 Oracle.  All rights reserved.
+ *
+ * $Id: os_flock.c 63573 2008-05-23 21:43:21Z trent.nelson $
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+
+/*
+ * __os_fdlock --
+ *	Acquire/release a lock on a byte in a file.
+ *
+ * PUBLIC: int __os_fdlock __P((ENV *, DB_FH *, off_t, int, int));
+ */
+int
+__os_fdlock(env, fhp, offset, acquire, nowait)
+	ENV *env;
+	DB_FH *fhp;
+	int acquire, nowait;
+	off_t offset;
+{
+#ifdef HAVE_FCNTL
+	DB_ENV *dbenv;
+	struct flock fl;
+	int ret, t_ret;
+
+	dbenv = env == NULL ? NULL : env->dbenv;
+
+	DB_ASSERT(env, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
+
+	if (dbenv != NULL && FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS_ALL))
+		__db_msg(env,
+		    "fileops: flock %s %s offset %lu",
+		    fhp->name, acquire ? "acquire": "release", (u_long)offset);
+
+	fl.l_start = offset;
+	fl.l_len = 1;
+	fl.l_type = acquire ? F_WRLCK : F_UNLCK;
+	fl.l_whence = SEEK_SET;
+
+	RETRY_CHK_EINTR_ONLY(
+	    (fcntl(fhp->fd, nowait ? F_SETLK : F_SETLKW, &fl)), ret);
+
+	if (ret == 0)
+		return (0);
+
+	if ((t_ret = __os_posix_err(ret)) != EACCES && t_ret != EAGAIN)
+		__db_syserr(env, ret, "fcntl");
+	return (t_ret);
+#else
+	COMPQUIET(fhp, NULL);
+	COMPQUIET(acquire, 0);
+	COMPQUIET(nowait, 0);
+	COMPQUIET(offset, 0);
+	__db_syserr(env, DB_OPNOTSUP, "advisory file locking unavailable");
+	return (DB_OPNOTSUP);
+#endif
+}