Can the /proc path be made configurable for the Process source?

[Juandavi1]

Hi, thanks for blazesym.

I'm using it to symbolize processes from a profiler that runs as a sidecar container. To see processes in sibling containers it needs the host's /proc, so we bind-mount the host /proc over the container's own /proc. That works great.

The snag is that the same container also has other code reading its own /proc/self (via gopsutil), and that code uses the container-namespace PID. Once /proc is the host's, it looks up the wrong PID (or one that isn't there) and crashes on startup.

If blazesym could read /proc from somewhere else, say /host/proc, we'd be fine: mount the host /proc there and leave the container's /proc alone. Right now it looks hardcoded:

• src/maps.rs:389 -> format!("/proc/{pid}/maps")
• src/maps.rs:213 -> format!("/proc/{pid}/map_files/...")

Two questions:

1. Is there already a way to point blazesym at a different /proc root that I missed?
2. If not, would you take a PR for it? I'm thinking an optional proc-root on the Process source, defaulting to /proc.

Thanks!

[d-e-s-o]

There is no way to use a different /proc currently. Can you just direct gopsutil to read a different /proc/ instead by using the HOST_PROC variable?

[Juandavi1]

Thanks! The catch with HOST_PROC is that we bind-mount the host /proc over the container's own /proc, so the container's own procfs isn't available at a second path to point gopsutil at and mounting a fresh procfs in Kubernetes needs CAP_SYS_ADMIN, which the agent doesn't have.

That's exactly why a proc-root option on blazesym's Process source would let us flip it the other way: host /proc at /host/proc, blazesym pointed there, container /proc left untouched, and gopsutil keeps working with no env changes.

Still happy to send that PR if you're open to it

[d-e-s-o]

But why can't you bind mount the original to a different location before layering the host's one over?

[Juandavi1]

We are running blazesym in an otel-agent sidecar that needs /proc for self monitoring