From 92c270d32caf3f8d5a02b8e46c7ec5d9d0315158 Mon Sep 17 00:00:00 2001 From: Joe Damato Date: Tue, 28 May 2024 17:37:06 +0000 Subject: [PATCH] Linux: Add epoll ioctls As of Linux kernel 6.9, some ioctls and a parameters structure have been introduced which allow user programs to control whether a particular epoll context will busy poll. Update the headers to include these for the convenience of user apps. The ioctls were added in Linux kernel 6.9 commit 18e2bf0edf4dd ("eventpoll: Add epoll ioctl for epoll_params") [1] to include/uapi/linux/eventpoll.h. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/diff/?h=v6.9&id=18e2bf0edf4dd Signed-off-by: Joe Damato Reviewed-by: Adhemerval Zanella --- NEWS | 3 + sysdeps/unix/sysv/linux/Makefile | 1 + sysdeps/unix/sysv/linux/sys/epoll.h | 14 ++++ sysdeps/unix/sysv/linux/tst-epoll-ioctls.c | 92 ++++++++++++++++++++++ 4 files changed, 110 insertions(+) create mode 100644 sysdeps/unix/sysv/linux/tst-epoll-ioctls.c diff --git a/NEWS b/NEWS index 84efa46df3..20e263f581 100644 --- a/NEWS +++ b/NEWS @@ -33,6 +33,9 @@ Major new features: more extensive verification tests for AT_SECURE programs and not meant to be a security feature. +* On Linux, update epoll header to include epoll ioctl definitions and + related structure added in Linux kernel 6.9. + Deprecated and removed features, and other changes affecting compatibility: * Architectures which use a 32-bit seconds-since-epoch field in struct diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 415aa1f14d..ae66590e91 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -200,6 +200,7 @@ tests += \ tst-clone2 \ tst-clone3 \ tst-epoll \ + tst-epoll-ioctls \ tst-fanotify \ tst-fdopendir-o_path \ tst-getauxval \ diff --git a/sysdeps/unix/sysv/linux/sys/epoll.h b/sysdeps/unix/sysv/linux/sys/epoll.h index fc8dce45c8..45e546fa44 100644 --- a/sysdeps/unix/sysv/linux/sys/epoll.h +++ b/sysdeps/unix/sysv/linux/sys/epoll.h @@ -19,6 +19,7 @@ #define _SYS_EPOLL_H 1 #include +#include #include #include @@ -87,6 +88,19 @@ struct epoll_event epoll_data_t data; /* User data variable */ } __EPOLL_PACKED; +struct epoll_params +{ + uint32_t busy_poll_usecs; + uint16_t busy_poll_budget; + uint8_t prefer_busy_poll; + + /* pad the struct to a multiple of 64bits */ + uint8_t __pad; +}; + +#define EPOLL_IOC_TYPE 0x8A +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params) +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params) __BEGIN_DECLS diff --git a/sysdeps/unix/sysv/linux/tst-epoll-ioctls.c b/sysdeps/unix/sysv/linux/tst-epoll-ioctls.c new file mode 100644 index 0000000000..618ecc4e86 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-epoll-ioctls.c @@ -0,0 +1,92 @@ +/* Basic tests for Linux epoll ioctls. + Copyright (C) 2022-2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void +test_epoll_ioctl (void) +{ + int efd = epoll_create1 (0); + TEST_VERIFY_EXIT (efd != -1); + + struct epoll_params params; + + TEST_COMPARE (ioctl (efd, EPIOCGPARAMS, ¶ms), 0); + + /* parameters are all 0 by default */ + TEST_COMPARE (params.busy_poll_usecs, 0); + TEST_COMPARE (params.busy_poll_budget, 0); + TEST_COMPARE (params.prefer_busy_poll, 0); + TEST_COMPARE (params.__pad, 0); + + /* set custom parameters */ + params.busy_poll_usecs = 40; + params.busy_poll_budget = 8; + params.prefer_busy_poll = 1; + params.__pad = 0; + + TEST_COMPARE (ioctl (efd, EPIOCSPARAMS, ¶ms), 0); + + memset (¶ms, 0, sizeof (params)); + + TEST_COMPARE (ioctl (efd, EPIOCGPARAMS, ¶ms), 0); + + /* check custom values were retrieved after being set */ + TEST_COMPARE (params.busy_poll_usecs, 40); + TEST_COMPARE (params.busy_poll_budget, 8); + TEST_COMPARE (params.prefer_busy_poll, 1); + TEST_COMPARE (params.__pad, 0); + + xclose (efd); +} + +static bool +ioctl_supported (void) +{ + int efd = epoll_create1 (0); + TEST_VERIFY_EXIT (efd != -1); + + struct epoll_params params; + int r = ioctl (efd, EPIOCGPARAMS, ¶ms); + xclose (efd); + + return (r == 0); +} + +static int +do_test (void) +{ + if (ioctl_supported ()) + test_epoll_ioctl (); + else + return EXIT_UNSUPPORTED; + + return 0; +} + +#include