On 6/8/21 1:20 PM, Daniel P. Berrangé wrote:
On Tue, Jun 08, 2021 at 12:45:51PM -0700, Richard Henderson wrote:
On 6/8/21 4:22 AM, Paolo Bonzini wrote:
+pam = not_found
+if not get_option('auth_pam').auto() or have_system
+ pam = cc.find_library('pam', has_headers: ['security/pam_appl.h'],
The condition doesn't look right.
Why are we looking for pam if --disable-pam-auth?
Surely
if not get_option('auth_pam').disabled() and have_system
This isn't entirely obvious at first glance, but the line after
the one you quote with the 'required' param makes it "do the
right thing (tm)".
The 'auth_pam' option is a tri-state taking 'enabled', 'disabled'
and 'auto', with 'auto' being the default state. When a tri-state
value is passed as the value of the 'required' parameter, then
required==enabled is interpreted as 'required=true'
required==auto is interpreted as 'required=false'
required==disabled means the entire call is a no-op
So this logic:
if not get_option('auth_pam').auto() or have_system
pam = cc.find_library('pam', has_headers: ['security/pam_appl.h'],
required: get_option('auth_pam'),
...)
Means
=> If 'auto' is set, then only look for the library if we're
building system emulators. In this case 'required:' will
evaluate to 'false', and so we'll gracefully degrade
if the library is missing.
If not have_system, there's no point in looking for pam *at all* regardless of
get_option().
=> If 'disabled' is set, then the 'find_library' call
will not look for anything, immediately return a
'not found' result and let the caller carry on.
This is not true. If 'required: false', find_library *will* look for the
library, but it will allow it to be missing.
From the meson docs:
meson.get_compiler('c').find_library('m', required: false),
...
The `required: false` means the build will continue when using another C library
that does not separate the maths library. See [Add math library (-lm)
portably](howtox.md#add-math-library-lm-portably).
So if auto, and not system, we will look for (and maybe find) pam. But then...
I guess through a complex sequence of events arrives at
softmmu_ss.add(authz, blockdev, chardev, crypto, io, qmp)
So pam doesn't get included into the user-only binaries anyway, but, geez.
r~
