Re: [libvirt] [Qemu-devel] [PATCH 1/2] add 'umask' option to -chardev

To use virtio-serial device, unix socket created for chardev with default umask(022) has insufficient permissions. e.g. start kvm guest with: -device virtio-serial \ -chardev socket,path=/tmp/foo,server,nowait,id=foo \ -device virtserialport,chardev=foo,name=org.fedoraproject.port.0 Check permissions for the socket file that has been created in the host to enable communication through virtual serial ports in the guest: #ls -l /tmp/somefile.sock srwxr-xr-x 1 qemu qemu 0 21. Jul 14:19 /tmp/somefile.sock Other users in the qemu group (like real user, test engines, etc) cannot write to this socket. Problem reported here: https://sourceware.org/bugzilla/show_bug.cgi?id=13078#c11 https://bugzilla.novell.com/show_bug.cgi?id=888166 This patch tries to add a 'umask' option to 'chardev', so that user can have chance to indicate a umask overwritting the default one (default is 022), then create unix sockets with expected permissions. Signed-off-by: Chunyan Liu <cyliu(a)suse.com&gt; --- This is patch for qemu. qemu-char.c | 3 +++ qemu-options.hx | 9 +++++++-- util/qemu-sockets.c | 12 +++++++++++- 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index 5d38395..facf2c6 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -680,7 +680,8 @@ int unix_listen_opts(QemuOpts *opts, Error **errp) { struct sockaddr_un un; const char *path = qemu_opt_get(opts, "path"); - int sock, fd; + int newmask = qemu_opt_get_number(opts, "umask", 0); + int sock, fd, oldmask; sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0); if (sock < 0) { @@ -708,10 +709,19 @@ int unix_listen_opts(QemuOpts *opts, Error **errp) } unlink(un.sun_path); + if (newmask) { + oldmask = umask(newmask); + } if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) { + if (newmask) { + umask(oldmask); + } error_set_errno(errp, errno, QERR_SOCKET_BIND_FAILED); goto err; } + if (newmask) { + umask(oldmask); + }