From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53452) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c1Eff-0003zy-72 for qemu-devel@nongnu.org; Mon, 31 Oct 2016 11:38:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c1Efe-0004qe-A5 for qemu-devel@nongnu.org; Mon, 31 Oct 2016 11:38:47 -0400 From: Fam Zheng Date: Mon, 31 Oct 2016 23:38:21 +0800 Message-Id: <1477928314-11184-2-git-send-email-famz@redhat.com> In-Reply-To: <1477928314-11184-1-git-send-email-famz@redhat.com> References: <1477928314-11184-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH 01/14] osdep: Add qemu_lock_fd and qemu_unlock_fd List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: "Daniel P. Berrange" , Kevin Wolf , Max Reitz , qemu-block@nongnu.org, rjones@redhat.com They are wrappers of POSIX fcntl "file private locking". Signed-off-by: Fam Zheng --- include/qemu/osdep.h | 2 ++ util/osdep.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 0e3c330..f15e122 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -294,6 +294,8 @@ int qemu_close(int fd); #ifndef _WIN32 int qemu_dup(int fd); #endif +int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive); +int qemu_unlock_fd(int fd, int64_t start, int64_t len); #if defined(__HAIKU__) && defined(__i386__) #define FMT_pid "%ld" diff --git a/util/osdep.c b/util/osdep.c index 06fb1cf..b85a490 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -140,6 +140,35 @@ static int qemu_parse_fdset(const char *param) { return qemu_parse_fd(param); } + +static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type) +{ +#ifdef F_OFD_SETLK + int ret; + struct flock fl = { + .l_whence = SEEK_SET, + .l_start = start, + .l_len = len, + .l_type = fl_type, + }; + do { + ret = fcntl(fd, F_OFD_SETLK, &fl); + } while (ret == -1 && errno == EINTR); + return ret == -1 ? -errno : 0; +#else + return -ENOTSUP; +#endif +} + +int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive) +{ + return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK); +} + +int qemu_unlock_fd(int fd, int64_t start, int64_t len) +{ + return qemu_lock_fcntl(fd, start, len, F_UNLCK); +} #endif /* -- 2.7.4