[v3,0/2] fs, close_range: add flag CLOSE_RANGE_CLOEXEC

Message

Giuseppe Scrivano Nov. 18, 2020, 10:47 a.m. UTC

When the new flag is used, close_range will set the close-on-exec bit
for the file descriptors instead of close()-ing them.

It is useful for e.g. container runtimes that want to minimize the
number of syscalls used after a seccomp profile is installed but want
to keep some fds open until the container process is executed.

v3:
- fixed indentation
- selftests: use ASSERT_EQ instead of EXPECT_EQ for hard failures

v2: https://lkml.kernel.org/lkml/[e-mail]/
- move close_range(..., CLOSE_RANGE_CLOEXEC) implementation to a separate function.
- use bitmap_set() to set the close-on-exec bits in the bitmap.
- add test with rlimit(RLIMIT_NOFILE) in place.
- use "cur_max" that is already used by close_range(..., 0).

v1: https://lkml.kernel.org/lkml/[e-mail]/

Giuseppe Scrivano (2):
  fs, close_range: add flag CLOSE_RANGE_CLOEXEC
  selftests: core: add tests for CLOSE_RANGE_CLOEXEC

 fs/file.c                                     | 44 ++++++++---
 include/uapi/linux/close_range.h              |  3 +
 .../testing/selftests/core/close_range_test.c | 74 +++++++++++++++++++
 3 files changed, 111 insertions(+), 10 deletions(-)

--
2.28.0

Comments

Christian Brauner Dec. 4, 2020, 11:32 a.m. UTC | #1

On Wed, Nov 18, 2020 at 11:47:44AM +0100, Giuseppe Scrivano wrote:
> When the new flag is used, close_range will set the close-on-exec bit
> for the file descriptors instead of close()-ing them.
> 
> It is useful for e.g. container runtimes that want to minimize the
> number of syscalls used after a seccomp profile is installed but want
> to keep some fds open until the container process is executed.
> 
> v3:
> - fixed indentation
> - selftests: use ASSERT_EQ instead of EXPECT_EQ for hard failures
> 
> v2: https://lkml.kernel.org/lkml/[e-mail]/
> - move close_range(..., CLOSE_RANGE_CLOEXEC) implementation to a separate function.
> - use bitmap_set() to set the close-on-exec bits in the bitmap.
> - add test with rlimit(RLIMIT_NOFILE) in place.
> - use "cur_max" that is already used by close_range(..., 0).
> 
> v1: https://lkml.kernel.org/lkml/[e-mail]/
> 
> Giuseppe Scrivano (2):
>   fs, close_range: add flag CLOSE_RANGE_CLOEXEC
>   selftests: core: add tests for CLOSE_RANGE_CLOEXEC
> 
>  fs/file.c                                     | 44 ++++++++---
>  include/uapi/linux/close_range.h              |  3 +
>  .../testing/selftests/core/close_range_test.c | 74 +++++++++++++++++++
>  3 files changed, 111 insertions(+), 10 deletions(-)

I've picked this up and stuffed it into -next. This solves a real
problem and I don't want it to sit around another merge window. (If you
pick it up later I'll simply drop it, Al.)

Christian