binfmt_misc: carry pre-opened interpreters in struct binfmt_misc_interp

An 'F' entry opens its interpreter at registration and every exec runs a
clone of that file. The file lives in a bare struct file pointer next to
the path it came from and put_binfmt_handler() closes it as a special
case.

Give the pre-opened interpreter a type of its own instead. struct
binfmt_misc_interp carries the file, the path it was opened from and a
selection name in a single allocation and is linked on a list that the
entry owns and tears down in put_binfmt_handler(). An 'F' entry binds a
single interpreter under the empty name and hands out clones of it as
before.

The open moves into open_interp_file() and works exactly as the
open-coded block in bm_register_write() did. It is opened for execution
at registration time, in the writer's context and with the credentials
the register file was opened with.

The entry can now own objects before it is published, so make
put_binfmt_handler() the single teardown. create_entry() returns the
entry with its reference held and every failure path in
bm_register_write() simply puts it. That also replaces the open-coded
bpf_ops release.

No functional changes. A later patch lets a 'B' entry bind multiple
interpreters selected by name per exec and reuses all of this.

Link: https://patch.msgid.link/20260730-work-binfmt_misc-preopen-v1-6-4a0b0da71f16@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions