diff options
| author | Michael Pratt <mpratt@google.com> | 2021-07-30 13:39:18 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-07-30 13:42:15 -0700 |
| commit | 62ea5c0a2212b9827f093551fc3da166facb9f0b (patch) | |
| tree | e26283ab57a11a34202cc731da4270c53c418951 /pkg/sentry/platform/kvm | |
| parent | 095b0d8348531b96f1b40885c00d6cd7f07ecf80 (diff) | |
checklinkname: rudimentary type-checking of linkname directives
This CL introduces a 'checklinkname' analyzer, which provides rudimentary
type-checking that verifies that function signatures on the local and remote
sides of //go:linkname directives match expected values.
If the Go standard library changes the definitions of any of these function,
checklinkname will flag the change as a finding, providing an error informing
the gVisor team to adapt to the upstream changes. This allows us to eliminate
the majority of gVisor's forward-looking negative build tags, as we can catch
mismatches in testing [1].
The remaining forward-looking negative build tags are covering shared struct
definitions, which I hope to add to checklinkname in a future CL.
[1] Of course, semantics/requirements can change without the signature
changing, so we still must be careful, but this covers the common case.
PiperOrigin-RevId: 387873847
Diffstat (limited to 'pkg/sentry/platform/kvm')
| -rw-r--r-- | pkg/sentry/platform/kvm/bluepill_unsafe.go | 10 | ||||
| -rw-r--r-- | pkg/sentry/platform/kvm/machine_unsafe.go | 8 |
2 files changed, 11 insertions, 7 deletions
diff --git a/pkg/sentry/platform/kvm/bluepill_unsafe.go b/pkg/sentry/platform/kvm/bluepill_unsafe.go index f63ab6aba..0f0c1e73b 100644 --- a/pkg/sentry/platform/kvm/bluepill_unsafe.go +++ b/pkg/sentry/platform/kvm/bluepill_unsafe.go @@ -12,10 +12,12 @@ // See the License for the specific language governing permissions and // limitations under the License. -//go:build go1.12 && !go1.18 -// +build go1.12,!go1.18 +//go:build go1.12 +// +build go1.12 -// Check go:linkname function signatures when updating Go version. +// //go:linkname directives type-checked by checklinkname. Any other +// non-linkname assumptions outside the Go 1 compatibility guarantee should +// have an accompanied vet check or version guard build tag. package kvm @@ -28,7 +30,7 @@ import ( ) //go:linkname throw runtime.throw -func throw(string) +func throw(s string) // vCPUPtr returns a CPU for the given address. // diff --git a/pkg/sentry/platform/kvm/machine_unsafe.go b/pkg/sentry/platform/kvm/machine_unsafe.go index 35660e827..cc3a1253b 100644 --- a/pkg/sentry/platform/kvm/machine_unsafe.go +++ b/pkg/sentry/platform/kvm/machine_unsafe.go @@ -12,10 +12,12 @@ // See the License for the specific language governing permissions and // limitations under the License. -//go:build go1.12 && !go1.18 -// +build go1.12,!go1.18 +//go:build go1.12 +// +build go1.12 -// Check go:linkname function signatures when updating Go version. +// //go:linkname directives type-checked by checklinkname. Any other +// non-linkname assumptions outside the Go 1 compatibility guarantee should +// have an accompanied vet check or version guard build tag. package kvm |