| Message ID | 1335886307-27586-3-git-send-email-stefanha@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Tue, May 01, 2012 at 04:31:44PM +0100, Stefan Hajnoczi wrote: > From: Anthony Liguori <aliguori@us.ibm.com> > > Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> > Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> > --- > 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 If we're going for a binary protocol, then I'd like to see it defined based on the XDR specification, so we can auto-generate our data marshallers/demarshallers using existing tools / libraries and not have to write something custom by hand. Your spec here is close enough that it would not be significant work. The changes would be - Everything is always big-endian - Each field has 4-byte alignment - Strings would have a u32 length, and the payload padded with NUL to the 4 byte boundary Daniel.
On Tue, May 01, 2012 at 04:31:44PM +0100, Stefan Hajnoczi wrote: > From: Anthony Liguori <aliguori@us.ibm.com> > > Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> > Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> > --- > 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] I think this should include the ID of the backend of the drive wanting this file opened, so you can reliably match up to the -drive that mgmt configured at startup. ie not have to search through every single device in the guest & all their backing files to find if there is a match. Regards, Daniel
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 + +If result is < 0, the value will be negated errno value as defined in errno.h. If +result is equal to 0, then there will also be a file descriptor available via SCM_RIGHTS +in the extended sendmsg data. + +ETEXI + HXCOMM This is the last statement. Insert new options before this line! STEXI @end table