From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47698) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZpdwG-0000YW-Vw for qemu-devel@nongnu.org; Fri, 23 Oct 2015 11:07:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZpdwC-0000xE-N6 for qemu-devel@nongnu.org; Fri, 23 Oct 2015 11:07:28 -0400 Received: from [98.143.106.101] (port=16532 helo=freebsd.org) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZpdwC-0000wm-Ha for qemu-devel@nongnu.org; Fri, 23 Oct 2015 11:07:24 -0400 From: Ed Maste Date: Fri, 23 Oct 2015 10:39:33 -0400 Message-Id: <1445611173-57034-1-git-send-email-emaste@freebsd.org> Subject: [Qemu-devel] [PATCH] tap-bsd: use user-specified tap device if it already exists List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org, Ed Maste --- As an aside this was reviewed on FreeBSD's Phabricator here: https://reviews.freebsd.org/D3969 net/tap-bsd.c | 38 +++++++++++++++++++++++++++++++++----- 1 file changed, 33 insertions(+), 5 deletions(-) diff --git a/net/tap-bsd.c b/net/tap-bsd.c index 7028d9b..0103a97 100644 --- a/net/tap-bsd.c +++ b/net/tap-bsd.c @@ -109,8 +109,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, #define PATH_NET_TAP "/dev/tap" -int tap_open(char *ifname, int ifname_size, int *vnet_hdr, - int vnet_hdr_required, int mq_required, Error **errp) +static int tap_open_clone(char *ifname, int ifname_size, Error **errp) { int fd, s, ret; struct ifreq ifr; @@ -126,7 +125,8 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, ret = ioctl(fd, TAPGIFNAME, (void *)&ifr); if (ret < 0) { error_setg_errno(errp, errno, "could not get tap interface name"); - goto error; + close(fd); + return -1; } if (ifname[0] != '\0') { @@ -135,19 +135,47 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, if (s < 0) { error_setg_errno(errp, errno, "could not open socket to set interface name"); - goto error; + close(fd); + return -1; } ifr.ifr_data = ifname; ret = ioctl(s, SIOCSIFNAME, (void *)&ifr); close(s); if (ret < 0) { error_setg(errp, "could not set tap interface name"); - goto error; + close(fd); + return -1; } } else { pstrcpy(ifname, ifname_size, ifr.ifr_name); } + return fd; +} + +int tap_open(char *ifname, int ifname_size, int *vnet_hdr, + int vnet_hdr_required, int mq_required, Error **errp) +{ + int fd = -1; + + /* If the specified tap device already exists just use it. */ + if (ifname[0] != '\0') { + char dname[100]; + snprintf(dname, sizeof dname, "/dev/%s", ifname); + TFR(fd = open(dname, O_RDWR)); + if (fd < 0 && errno != ENOENT) { + error_setg_errno(errp, errno, "could not open %s", dname); + return -1; + } + } + + if (fd < 0) { + /* Tap device not specified or does not exist. */ + if ((fd = tap_open_clone(ifname, ifname_size, errp)) < 0) { + return -1; + } + } + if (*vnet_hdr) { /* BSD doesn't have IFF_VNET_HDR */ *vnet_hdr = 0; -- 2.4.6