Re: [libvirt] [RFC 2/5] block: add new command line parameter that and protocol description

From: Anthony Liguori <aliguori(a)us.ibm.com&gt; Signed-off-by: Anthony Liguori <aliguori(a)us.ibm.com&gt; Signed-off-by: Stefan Hajnoczi <stefanha(a)linux.vnet.ibm.com&gt; --- qemu-options.hx | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/qemu-options.hx b/qemu-options.hx index a169792..ccf4d1d 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2724,6 +2724,48 @@ DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "-qtest-log LOG specify tracing options\n", QEMU_ARCH_ALL) +DEF("open-hook-fd", HAS_ARG, QEMU_OPTION_open_hook_fd, + "-open-hook-fd <fd>\n" + " delegate opens to external process using <fd>\n", QEMU_ARCH_ALL) +STEXI +@item -open-hook-fd @var{fd} +@findex -open-hook-fd +Delegates open()s to an external process using @var<fd> to communicate commands. +@var<fd> should be an open Unix Domain socket pipe that file descriptors can be +received from. The protocol the socket uses is a simple request/response initiated +by the client. All integers are in host byte order. It is assumed that this protocol +is only ever used on the same physical machine. It is currently defined as: + +u32 message_size +u32 command +u8 payload[message_size - 8] + +The contents of payload depend on command. Currently the following commands are +defined: + +1. QEMU_OPEN (1) + +The full message will be: + +u32 message_size +u32 command = 1 +u32 flags (O_ flags defined by libc) +u32 mode (mode_t flags as defined by libc) +u16 filename_len; +u8 filename[filename_len] + +The server will then respond with: + +u32 message_size +u32 command = 1 +s32 result