1 //===---------- Linux implementation of the epoll_wait function -----------===// 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/sys/epoll/epoll_wait.h" 10 11 #include "hdr/signal_macros.h" // for NSIG 12 #include "hdr/types/sigset_t.h" 13 #include "hdr/types/struct_epoll_event.h" 14 #include "src/__support/OSUtil/syscall.h" // For internal syscall function. 15 #include "src/__support/common.h" 16 #include "src/__support/macros/config.h" 17 #include "src/__support/macros/sanitizer.h" 18 #include "src/errno/libc_errno.h" 19 20 #include <sys/syscall.h> // For syscall numbers. 21 22 namespace LIBC_NAMESPACE_DECL { 23 24 LLVM_LIBC_FUNCTION(int, epoll_wait, 25 (int epfd, struct epoll_event *events, int maxevents, 26 int timeout)) { 27 #ifdef SYS_epoll_wait 28 int ret = LIBC_NAMESPACE::syscall_impl<int>( 29 SYS_epoll_wait, epfd, reinterpret_cast<long>(events), maxevents, timeout); 30 #elif defined(SYS_epoll_pwait) 31 int ret = LIBC_NAMESPACE::syscall_impl<int>( 32 SYS_epoll_pwait, epfd, reinterpret_cast<long>(events), maxevents, timeout, 33 reinterpret_cast<long>(nullptr), NSIG / 8); 34 #else 35 #error "epoll_wait and epoll_pwait are unavailable. Unable to build epoll_wait." 36 #endif 37 // A negative return value indicates an error with the magnitude of the 38 // value being the error code. 39 if (ret < 0) { 40 libc_errno = -ret; 41 return -1; 42 } 43 44 MSAN_UNPOISON(events, ret * sizeof(struct epoll_event)); 45 46 return ret; 47 } 48 49 } // namespace LIBC_NAMESPACE_DECL 50