This code uses the hashtable directly to avoid the overhead of calling
the path which creates ProcessInfo entries. So we need to also handle
the chance the lookaside is NULL.
The /sysroot/ convention is something we see on OSTree-based systems
such as Silverblue or CoreOS which contains the running image. We can
skip that part of the path so that symbol resolving continues as normal.
We are starting to come into a situation where we need more advanced
path translations because we keep having to do things like this. Until
Linux figures out file-system namespaces at a higher level at least.
Really what we want to deal with here is tracking an overlay that we may
need to be able to decode after the fact (in case processes exit or we
need to do post-processing symbol resolution).
For the podman case, that is $some_path mapped to root (/), generally
speaking. For flatpak though, that would have two mappings, one for
/app and another for /usr (possibly more).
We want to know the location of our root if it was specified in the
capture file. Such is useful for decoding symbols that may not be
reported right from perf tooling.
This allows us to try to translate maps for processes in containers.
This is meant to allow us to find the debug files for a given library for
podman containers running as the current user. However, we still need to
try to translate the fuse-overlayfs paths when parsing the /proc/pid/mounts
or we'll have incorrect paths coming from the event stream.
As we gain in usage, we need to be more careful about using a prefix
that will not collide with other symbols. So version 3 of our ABI will
change to using Sysprof/SYSPROF/sysprof as the various prefixes.
The soname/api version bump will happen later on this branch so that
things are easier to test up until then.
