On 09/06/2011 04:44 AM, Daniel Veillard wrote:
On Tue, Sep 06, 2011 at 06:18:40PM +0800, Hu Tao wrote:--- daemon/remote.c | 15 +++++++++++++++ include/libvirt/libvirt.h.in | 4 +++- src/remote/remote_driver.c | 15 +++++++++++++++ src/remote/remote_protocol.x | 2 ++ 4 files changed, 35 insertions(+), 1 deletions(-) +++ b/include/libvirt/libvirt.h.in @@ -481,7 +481,8 @@ typedef enum { VIR_TYPED_PARAM_LLONG = 3, /* long long case */ VIR_TYPED_PARAM_ULLONG = 4, /* unsigned long long case */ VIR_TYPED_PARAM_DOUBLE = 5, /* double case */ - VIR_TYPED_PARAM_BOOLEAN = 6 /* boolean(character) case */ + VIR_TYPED_PARAM_BOOLEAN = 6, /* boolean(character) case */ + VIR_TYPED_PARAM_STRING = 7 /* string case */
New enum value is probably okay,
} virTypedParameterType; /** @@ -512,6 +513,7 @@ struct _virTypedParameter { unsigned long long int ul; /* type is ULLONG */ double d; /* type is DOUBLE */ char b; /* type is BOOLEAN */ + char *s; /* type is STRING */
and new char * field to a union doesn't change the struct size,
+++ b/src/remote/remote_protocol.x @@ -314,6 +314,8 @@ union remote_typed_param_value switch (int type) { double d; case VIR_TYPED_PARAM_BOOLEAN: int b; + case VIR_TYPED_PARAM_STRING: + remote_nonnull_string s;
but I'm quite worried about the on-the-wire compatibility aspect of this change. If a new server sends the new enum value and a string, will the old server that does not know that enum value properly reject the rpc call, or will it cause a crash or other bad things to happen?
}; struct remote_typed_param {Ohhh, good point and better to add this before the first official release to avoid possible ABI breakages in the future if we need it !
Huh? remote_typed_param has already had an official release. The addition is to a union, but this really is a case of modifying an existing on-the-wire layout, so I hope that the fact that it was an enumerated union with a new enumeration value is what is making this safe.
Also, before you push this, please install pdwtags (from the dwarves package if you use Fedora), and fix src/remote_protocol-structs so that 'make check' passes. Actually, please post that diff before pushing the patch - I want to verify that the size of remote_typed_param doesn't change; if it does change, then we have an incompatible change, and need to think of a different approach.
-- Eric Blake eblake@xxxxxxxxxx +1-801-349-2682 Libvirt virtualization library http://libvirt.org -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list