diff options
| author | Matt Whitlock <gentoo@mattwhitlock.name> | 2022-08-21 09:10:44 -0400 |
|---|---|---|
| committer | William Hubbs <w.d.hubbs@gmail.com> | 2023-01-20 21:44:37 -0600 |
| commit | 9dfd2b2737351083e5bed173bda1acd01a70c510 (patch) | |
| tree | 2887e6ed7bdc12f3dd1b13da94e6f59a25dc950d /meson.build | |
| parent | de295bd0c63f15e3d4e797e053826dbacbce556e (diff) | |
start-stop-daemon, supervise-daemon: use closefrom()/close_range()
On systems with a very large RLIMIT_NOFILE, calling close() in a loop
from 3 to getdtablesize() effects an enormous number of system calls.
There are better alternatives. Both BSD and Linux have the closefrom()
system call that closes all file descriptors with indices not less than
a specified minimum. Have start-stop-daemon call closefrom() on systems
where it's implemented, falling back to the old loop elsewhere.
Likewise, calling fcntl(i, F_SETFD, FD_CLOEXEC) in a loop from 3 to
getdtablesize() raises a similar performance concern. Linux 5.11 and
onward has a close_range() system call with a CLOSE_RANGE_CLOEXEC flag
that sets the FD_CLOEXEC flag on all file descriptors in a specified
range. Have supervise-daemon utilize this feature on systems where it's
implemented, falling back to the old loop elsewhere.
Diffstat (limited to 'meson.build')
| -rw-r--r-- | meson.build | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/meson.build b/meson.build index fac5ac49..979517a9 100644 --- a/meson.build +++ b/meson.build @@ -192,6 +192,14 @@ if cc.compiles(malloc_attribute_test, name : 'malloc attribute with arguments') add_project_arguments('-DHAVE_MALLOC_EXTENDED_ATTRIBUTE', language: 'c') endif +if cc.has_function('closefrom', prefix: '#define _GNU_SOURCE\n#include <unistd.h>') + add_project_arguments('-DHAVE_CLOSEFROM', language: 'c') +endif +if cc.has_function('close_range', prefix: '#define _GNU_SOURCE\n#include <unistd.h>') and \ + cc.has_header_symbol('unistd.h', 'CLOSE_RANGE_CLOEXEC', prefix: '#define _GNU_SOURCE') + add_project_arguments('-DHAVE_CLOSE_RANGE_CLOEXEC', language: 'c') +endif + incdir = include_directories('src/shared') einfo_incdir = include_directories('src/libeinfo') rc_incdir = include_directories('src/librc') |