[pseudo] [PATCH v3 0/2] close_range: implement it rather than return ENOSYS

Richard, I took the writing rather than leave it to you. This is the one
op version.

close_range() and closefrom() both go through OP_CLOSE_RANGE now. Based on
the two commits you have on master-next (5ce47e3 + 2d235dd), and the only
changes from those are:

  - OP_CLOSEFROM dropped from enums/op.in.
  - Its case in pseudo_client_op() went with it. OP_CLOSE_RANGE already
    does the same walk over pseudo's own descriptors, and the ignore-path
    exemption now names one op instead of two.
  - closefrom() calls the op with INT_MAX for the maximum.
  - pseudo_client_closefrom() folded into pseudo_client_close_range(),
    which clamps to nfds anyway, so INT_MAX means what closefrom() wants.

The rest is your version, tweaks and all. pseudo_client.c comes out at
+28/-10 against master rather than +67/-1.

2/2 is your test commit with nothing touched in it. I dropped your
Signed-off-by from both, since 1/2 is no longer the code you signed off on
and carrying it on 2/2 alone looked worse than dropping both.

Tested on x86_64, glibc 2.39, kernel 6.17.0-22:

  - ./run_tests.sh: 45 tests, 5 skipped for missing xattr and acl support
    in this container, everything else passing except test-parallel-rename
    and test-parallel-symlinks. Those two are flaky here rather than
    broken by this: they fail on pristine 2a5521e as well, and across
    three runs of this branch one of them passed once.
  - The probe matrix from July, run against this branch and against a build
    of your master-next version: byte identical output. It covers
    close_range(fd, ~0U, 0) with no path lists, under PSEUDO_IGNORE_PATHS,
    and under an OE-style PSEUDO_INCLUDE_PATHS, the maxfd variants
    (~0U, UINT_MAX-1, INT_MAX, 4096, fd), closefrom() under that same
    include list, and pseudo still faking ownership after both calls.
  - linux-libc-headers do_install, with pseudo-native built from this
    branch: succeeds. That is the task that died on valkyrie in July.

One gap I should name: the suite has no closefrom() test, so what the
rewiring did to closefrom is covered by that probe and not by anything in
the tree. I left it out because closefrom() is not declared before glibc
2.34 and I did not want to guess at what that does to the test build on
older hosts. Happy to add a case to 2/2 if you would rather have it.

Babanpreet Singh (2):
  ports/linux/guts: Implement close_range() instead of returning ENOSYS
  tests: Add close_range() test

 enums/op.in                    |   2 +-
 ports/linux/guts/close_range.c |  59 ++++++-
 ports/linux/guts/closefrom.c   |   3 +-
 ports/linux/portdefs.h         |  16 ++
 pseudo_client.c                |  38 +++--
 test/test-close-range.c        | 283 +++++++++++++++++++++++++++++++++
 test/test-close-range.sh       |  24 +++
 7 files changed, 406 insertions(+), 19 deletions(-)
 create mode 100644 test/test-close-range.c
 create mode 100755 test/test-close-range.sh

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2.43.0