Unverified Commit affe1324 authored by Pengxiang Huang's avatar Pengxiang Huang Committed by GitHub
Browse files

Add named posix semaphore lifetime operations on linux (#192278) 

This implements the second part of #190847 

Specifically, this pr adds `sem_open`, `sem_close`, and `sem_unlink` for
posix semaphore on linux.
https://pubs.opengroup.org/onlinepubs/9799919799/functions/sem_open.html

https://pubs.opengroup.org/onlinepubs/9799919799/functions/sem_close.html

https://pubs.opengroup.org/onlinepubs/9799919799/functions/sem_unlink.html

Since it targets on linux implementation, two extra things are added:
1. add system call wrappers for `mmap`, `munmap`, `link`, `unlink`, and
`ftruncate`. Those are necessary for the implementation of semaphore on
linux. Wrappers is added based on the refactor proposal:
https://libc.llvm.org/dev/syscall_wrapper_refactor.html.
2. refactor the previous semaphore implementation, put it under `linux/`
since its based on linux.
parent 01aefba7

libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt

+38 −0
Original line number Diff line number Diff line
@@ -327,3 +327,41 @@ add_header_library( 
    libc.include.sys_syscall

)



add_header_library(

  ftruncate

  HDRS

    ftruncate.h

  DEPENDS

    libc.src.__support.OSUtil.osutil

    libc.src.__support.common

    libc.src.__support.error_or

    libc.src.__support.macros.config

    libc.hdr.types.off_t

    libc.include.sys_syscall

)



add_header_library(

  link

  HDRS

    link.h

  DEPENDS

    libc.src.__support.OSUtil.osutil

    libc.src.__support.common

    libc.src.__support.error_or

    libc.src.__support.macros.config

    libc.hdr.fcntl_macros

    libc.include.sys_syscall

)



add_header_library(

  unlink

  HDRS

    unlink.h

  DEPENDS

    libc.src.__support.OSUtil.osutil

    libc.src.__support.common

    libc.src.__support.error_or

    libc.src.__support.macros.config

    libc.hdr.fcntl_macros

    libc.include.sys_syscall

)

libc/src/__support/OSUtil/linux/syscall_wrappers/ftruncate.h

0 → 100644
+41 −0
Original line number Diff line number Diff line 
//===-- Implementation header for ftruncate ---------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//



#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_FTRUNCATE_H

#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_FTRUNCATE_H



#include "hdr/types/off_t.h"

#include "src/__support/OSUtil/linux/syscall.h" // syscall_impl

#include "src/__support/common.h"

#include "src/__support/error_or.h"

#include "src/__support/macros/config.h"

#include <sys/syscall.h> // For syscall numbers



namespace LIBC_NAMESPACE_DECL {

namespace linux_syscalls {



LIBC_INLINE ErrorOr<int> ftruncate(int fd, off_t len) {

#ifdef SYS_ftruncate

  int ret = syscall_impl<int>(SYS_ftruncate, fd, len);

#elif defined(SYS_ftruncate64)

  // Same as ftruncate but can handle large offsets on 32-bit systems.

  static_assert(sizeof(off_t) == 8);

  int ret = syscall_impl<int>(SYS_ftruncate64, fd, (long)len,

                              (long)(((uint64_t)(len)) >> 32));

#else

#error "ftruncate and ftruncate64 syscalls not available."

#endif

  if (ret < 0)

    return Error(-static_cast<int>(ret));

  return 0;

}



} // namespace linux_syscalls

} // namespace LIBC_NAMESPACE_DECL



#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_FTRUNCATE_H

libc/src/__support/OSUtil/linux/syscall_wrappers/link.h

0 → 100644
+39 −0
Original line number Diff line number Diff line 
//===-- Implementation header for link --------------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//



#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_LINK_H

#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_LINK_H



#include "hdr/fcntl_macros.h"                   // AT_FDCWD

#include "src/__support/OSUtil/linux/syscall.h" // syscall_impl

#include "src/__support/common.h"

#include "src/__support/error_or.h"

#include "src/__support/macros/config.h"

#include <sys/syscall.h> // For syscall numbers



namespace LIBC_NAMESPACE_DECL {

namespace linux_syscalls {



LIBC_INLINE ErrorOr<int> link(const char *oldpath, const char *newpath) {

#ifdef SYS_link

  int ret = syscall_impl<int>(SYS_link, oldpath, newpath);

#elif defined(SYS_linkat)

  int ret =

      syscall_impl<int>(SYS_linkat, AT_FDCWD, oldpath, AT_FDCWD, newpath, 0);

#else

#error "link and linkat syscalls not available."

#endif

  if (ret < 0)

    return Error(-static_cast<int>(ret));

  return 0;

}



} // namespace linux_syscalls

} // namespace LIBC_NAMESPACE_DECL



#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_LINK_H

libc/src/__support/OSUtil/linux/syscall_wrappers/unlink.h

0 → 100644
+38 −0
Original line number Diff line number Diff line 
//===-- Implementation header for unlink ------------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//



#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_UNLINK_H

#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_UNLINK_H



#include "hdr/fcntl_macros.h"                   // AT_FDCWD

#include "src/__support/OSUtil/linux/syscall.h" // syscall_impl

#include "src/__support/common.h"

#include "src/__support/error_or.h"

#include "src/__support/macros/config.h"

#include <sys/syscall.h> // For syscall numbers



namespace LIBC_NAMESPACE_DECL {

namespace linux_syscalls {



LIBC_INLINE ErrorOr<int> unlink(const char *path) {

#ifdef SYS_unlink

  int ret = syscall_impl<int>(SYS_unlink, path);

#elif defined(SYS_unlinkat)

  int ret = syscall_impl<int>(SYS_unlinkat, AT_FDCWD, path, 0);

#else

#error "unlink and unlinkat syscalls not available."

#endif

  if (ret < 0)

    return Error(-static_cast<int>(ret));

  return 0;

}



} // namespace linux_syscalls

} // namespace LIBC_NAMESPACE_DECL



#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_UNLINK_H

libc/src/semaphore/CMakeLists.txt

+7 −8
Original line number Diff line number Diff line 
add_header_library(

  posix_semaphore

  HDRS

    posix_semaphore.h

  DEPENDS

    libc.src.__support.CPP.atomic

    libc.src.__support.threads.futex_utils

)
 
if(NOT TARGET libc.src.__support.OSUtil.osutil)

  return()

endif()



if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})

  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})

endif()