Stop prepending prefix to the result of realpath(3).

[kib]

Summary

The path is already absolute.

Noted by: rstone

[rstone]

libexec/rtld-elf/rtld.c

5571 ↗

(On Diff #66589)

This will change /foo/symlink to /bar/target where we didn't before. That's not an enormous deal, but realpath will fail within a capsicum sandbox as it needs to be able to stat every component of the path, including "/". I'd prefer to only use realpath on relative paths for this reason.

[kib]

libexec/rtld-elf/rtld.c

5571 ↗

(On Diff #66589)

So do you want realpath(3) at all there ?

[kib]

libexec/rtld-elf/rtld.c

5571 ↗

(On Diff #66589)

I can test with cap_getmode(2) and only call realpath if not in cap mode.

This is also a valid question for $ORIGIN resolution, where we use realpath(3) as well. See some minimal discussion with completely wrong patch at D23043.

[kib]

Do not use realpath() on abs path.