Unprivileged objNameAllowsDot, return *btf.Var from Variable{Spec}.Type()
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When loading ELFs using unprivileged tools or tests, EPERM causes dots and underscores to be stripped from MapSpec.Name, causing strange results for maps like .rodata.foo. Also, only consider ErrNotSupported as conclusive and bubble up any other errors to the caller. Most callers just check err != nil, but in case someone indirectly relies on the sentinel, this should result in more accurate output. Signed-off-by: Timo Beckers <[email protected]>
In the initial design, we decided to return the inner type from .Type(), but I forgot the outer btf.Var was needed to access decl tags set on the variable. Returning a *Var here is the most convenient way of accessing the tags, otherwise the caller would need to find the underlying map and parse the datasec manually, which goes against what this API aims to solve. Instead of the initial idea of returning a btf.Var as btf.Type, this now returns btf.Var directly. Signed-off-by: Timo Beckers <[email protected]>
Cilium's variable inliner needs this information to look up variable contents based on the offset specified in the instruction stream, and wants to validate that it's pulling data from the right data section. It makes for a slightly leaky abstraction, but at least something meaningful can be accomplished by combining the two, e.g. by accessing the given offset in the map. Signed-off-by: Timo Beckers <[email protected]>
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Removed breaking-change label as this API is yet to appear in a release. |
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Fixes for a few papercuts encountered while implementing the API into the Cilium agent.
Changed my mind about returning btf.Type from .Type(), this should just be *btf.Var. No need in obscuring the Var, it's the easiest way to get to decl tags.