On 02/12/2013 01:15 PM, Laine Stump wrote: > If a uid and/or gid is specified for a command, it will be set just > after the user-supplied post-fork "hook" function is called. > > The intent is that this can replace user hook functions that set > uid/gid. This moves the setting of uid/gid and dropping of > capabilities closer to each other, which is important since the two > should really be done at the same time (libcapng provides a single > function that does both, which we will be unable to use, but want to > mimic as closely as possible). > --- > Change from V1: > * only bypass uid/gid setting if they are -1 > * cast -1 to ([gu]id_t) when comparing to a [gu]id_t > * cast uid and gid to (int) for printing > > src/libvirt_private.syms | 2 ++ > src/util/vircommand.c | 29 +++++++++++++++++++++++++++++ > src/util/vircommand.h | 6 +++++- > 3 files changed, 36 insertions(+), 1 deletion(-) > > diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms > index b9d45a2..511a686 100644 > --- a/src/libvirt_private.syms > +++ b/src/libvirt_private.syms > @@ -158,12 +158,14 @@ virCommandRun; > virCommandRunAsync; > virCommandSetErrorBuffer; > virCommandSetErrorFD; > +virCommandSetGID; > virCommandSetInputBuffer; > virCommandSetInputFD; > virCommandSetOutputBuffer; > virCommandSetOutputFD; > virCommandSetPidFile; > virCommandSetPreExecHook; > +virCommandSetUID;
Is it common enough to set both gid/uid at once, in order to make this a
single function virCommandSetUIDGID?
> @@ -605,6 +607,13 @@ virExec(virCommandPtr cmd)
> goto fork_error;
> }
>
> + if (cmd->uid != (uid_t)-1 || cmd->gid != (gid_t)-1) {
> + VIR_DEBUG("Setting child uid:gid to %d:%d",
> + (int)cmd->uid, (int)cmd->gid);
> + if (virSetUIDGID(cmd->uid, cmd->gid) < 0)
In fact, down at a lower layer in the stack, we pass both ids at once.
Hmm, in the chown() case, doing both at once lets you use one syscall
instead of two; but in the set*id() functions, it's separate syscalls
for uid vs. gid no matter what we do, so I guess it doesn't really
matter whether it is two separate calls or one combined call higher up
in the stack. But what you have with separate calls works, so I don't
mind whether you keep it as-is, to save the hassle of rippling a
combined call through the rest of the series.
ACK.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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