selftests/exec: test interpreters bound to a 'B' entry

2026-07-31T08:38:24+00:00

One handler, one entry registered disabled, an interpreter per guest architecture bound to a file one write at a time. The load program picks one by name per exec: - an aarch64 binary runs the interpreter bound as "first" and a riscv one the interpreter bound as "second", from a single entry and a single handler - unlinking a bound interpreter and putting a different binary in its place changes nothing, which is what the binding exists for - the entry reports what it bound, under the names it bound them as - a name the entry did not bind fails the exec with -ENOENT rather than falling back to anything - activating the entry refuses further binding with -EBUSY, a later disable does not undo that, and an entry registered without 'D' never accepted a '+' write to begin with - a name binds one interpreter, and control characters are refused - the command has to end at the write, bytes past an embedded nul are refused - an entry binds at most 100 interpreters, the next one is refused with -ENOSPC The test interpreter prints its argv[0], which is the path the kernel ran that copy under, so one binary installed at two paths tells the harness which of them the program picked. Link: https://patch.msgid.link/20260730-work-binfmt_misc-preopen-v1-8-4a0b0da71f16@kernel.org Signed-off-by: Christian Brauner (Amutable)

linux-next.git/tools/testing/selftests/exec/interp_bind.bpf.c, branch master

selftests/exec: test interpreters bound to a 'B' entry