From owner-freebsd-questions Thu May 6 22:31:38 1999 Delivered-To: freebsd-questions@freebsd.org Received: from polio.ecst.csuchico.edu (polio.ecst.csuchico.edu [132.241.4.13]) by hub.freebsd.org (Postfix) with SMTP id 6889614C35 for ; Thu, 6 May 1999 22:31:36 -0700 (PDT) (envelope-from manek@ecst.csuchico.edu) Received: (qmail 8045 invoked by uid 21024); 6 May 1999 22:31:35 -0700 Date: Thu, 6 May 1999 22:31:35 -0700 (PDT) From: "Sameer R. Manek" To: freebsd-questions@freebsd.org, freebsd-hackers@freebsd.org Subject: bug with lockf(3)? Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG I had posted this originally to freebsd-stable but didn't get any response from that list. On freebsd 3-1-stable I'm not sure if this is a bug or my misinterpetation of how lockf() works. But here's the situation. Given 2 processes A and B, both with open file descriptors to a file, using open ("file.txt",O_RDWR) A calls lockf (fd,F_LOCK,0) and proceeds to read/write to file while file is still locked....including using lseek to jump to the begining of the file B calls lockf (fd,F_LOCK,0) and enters blocked state A calls lockf (fd,F_ULOCK,0) B is still in blocked state, until A exit(3)s. According to the man page: F_LOCK and F_TLOCK requests differ only by the action taken if the section is not available. F_LOCK blocks the calling process until the section is available. F_TLOCK makes the function fail if the section is already locked by another process. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Sameer Manek manek@ecst.csuchico.edu "They that will sacrifice liberty in exchange for temporary safety deserve neither liberty or safety." -Ben Franklin -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message