BTrace Permission Policy (Simplified)

Minimal, per-extension policy that decides whether an extension may link its implementation. API types remain available on the bootstrap classpath so SHIMs can be generated when implementations are blocked.

Sources (first found wins)

• -Dbtrace.permissions=/path/to/permissions.properties
• ~/.btrace/permissions.properties or ~/.config/btrace/permissions.properties
• Classpath resource META-INF/btrace/permissions.properties

Agent Arguments (optional)

• allowExtensions=<id1,id2>: allow specific extension IDs to link implementations.
• denyExtensions=<id1,id2>: block specific extension IDs (SHIM fallback only).
• allowPrivileged=true|false: allow all privileged extensions to link implementations.
• Launch-time grants (e.g., grant=..., deny=..., grantAll=...) remain supported but are not part of the policy file and are not required for allow/deny decisions.

File Format (properties)

• allowExtensions=id1,id2
• denyExtensions=id3,id4
• allowPrivileged=false

Example:

allowExtensions=btrace-statsd,my-metrics
denyExtensions=legacy-foo
allowPrivileged=false

Behavior

• If an extension ID is denied, the implementation is not linked; APIs remain available for SHIMs.
• If an extension is privileged (declares any privileged required permissions) and is neither explicitly allowed nor covered by allowPrivileged=true, its implementation is blocked (SHIMs still available).
• “Required permissions” remain visible in logs and listings to inform the operator’s decision; no fine-grained per-permission policy evaluation is performed.