libc/src/sched/linux/sched_rr_get_interval.cpp

   1 //===-- Implementation of sched_rr_get_interval ---------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/sched/sched_rr_get_interval.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13 #include "src/__support/macros/config.h"
  14 #include "src/errno/libc_errno.h"
  15
  16 #include <sys/syscall.h> // For syscall numbers.
  17
  18 #ifdef SYS_sched_rr_get_interval_time64
  19 #include <linux/time_types.h> // For __kernel_timespec.
  20 #endif
  21
  22 namespace LIBC_NAMESPACE_DECL {
  23
  24 LLVM_LIBC_FUNCTION(int, sched_rr_get_interval,
  25                    (pid_t tid, struct timespec *tp)) {
  26 #ifdef SYS_sched_rr_get_interval
  27   int ret =
  28       LIBC_NAMESPACE::syscall_impl<int>(SYS_sched_rr_get_interval, tid, tp);
  29 #elif defined(SYS_sched_rr_get_interval_time64)
  30   // The difference between the  and SYS_sched_rr_get_interval
  31   // SYS_sched_rr_get_interval_time64 syscalls is the data type used for the
  32   // time interval parameter: the latter takes a struct __kernel_timespec
  33   int ret;
  34   if (tp) {
  35     struct __kernel_timespec ts32;
  36     ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_sched_rr_get_interval_time64,
  37                                             tid, &ts32);
  38     if (ret == 0) {
  39       tp->tv_sec = ts32.tv_sec;
  40       tp->tv_nsec = static_cast<long int>(ts32.tv_nsec);
  41     }
  42   } else
  43     // When tp is a nullptr, we still do the syscall to set ret and errno
  44     ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_sched_rr_get_interval_time64,
  45                                             tid, nullptr);
  46 #else
  47 #error                                                                         \
  48     "sched_rr_get_interval and sched_rr_get_interval_time64 syscalls not available."
  49 #endif
  50   if (ret < 0) {
  51     libc_errno = -ret;
  52     return -1;
  53   }
  54   return 0;
  55 }
  56
  57 } // namespace LIBC_NAMESPACE_DECL