[libc-commits] [libc] [libc][POSIX][poll.h] implement poll (PR #125118)

via libc-commits libc-commits at lists.llvm.org
Thu Jan 30 13:23:50 PST 2025 

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

<details>
<summary>Changes</summary>

Simple syscall.

Fixes: #<!-- -->124647


---
Full diff: https://github.com/llvm/llvm-project/pull/125118.diff


19 Files Affected:

- (modified) libc/config/linux/x86_64/entrypoints.txt (+3) 
- (modified) libc/hdr/types/CMakeLists.txt (+16) 
- (added) libc/hdr/types/nfds_t.h (+23) 
- (added) libc/hdr/types/struct_pollfd.h (+23) 
- (modified) libc/include/CMakeLists.txt (+10) 
- (modified) libc/include/llvm-libc-macros/CMakeLists.txt (+6) 
- (modified) libc/include/llvm-libc-macros/linux/CMakeLists.txt (+6) 
- (added) libc/include/llvm-libc-macros/linux/poll-macros.h (+65) 
- (added) libc/include/llvm-libc-macros/poll-macros.h (+16) 
- (modified) libc/include/llvm-libc-types/CMakeLists.txt (+6-4) 
- (added) libc/include/llvm-libc-types/nfds_t.h (+14) 
- (added) libc/include/llvm-libc-types/struct_pollfd.h (+18) 
- (added) libc/include/poll.yaml (+16) 
- (modified) libc/src/CMakeLists.txt (+1) 
- (added) libc/src/poll/linux/CMakeLists.txt (+14) 
- (added) libc/src/poll/linux/poll.cpp (+31) 
- (added) libc/src/poll/poll.h (+22) 
- (modified) libc/test/src/CMakeLists.txt (+1) 
- (added) libc/test/src/poll/poll_test.cpp (+18) 


``````````diff
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 366e4d34294d15..b8600059430f85 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -32,6 +32,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # poll.h entrypoints
+    libc.src.poll.poll
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min
diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index 3dfa38a020fad0..dfc90009ef54a8 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -342,3 +342,19 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.struct_iovec
     libc.include.sys_uio
 )
+
+add_proxy_header_library(
+  nfds_t
+  HDRS
+    nfds_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.nfds_t
+)
+
+add_proxy_header_library(
+  struct_pollfd
+  HDRS
+    struct_pollfd.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.struct_pollfd
+)
diff --git a/libc/hdr/types/nfds_t.h b/libc/hdr/types/nfds_t.h
new file mode 100644
index 00000000000000..9143564c2333e7
--- /dev/null
+++ b/libc/hdr/types/nfds_t.h
@@ -0,0 +1,23 @@
+//===-- Definition of nfds_t ----------------------------------------------===//
+//
+// 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_HDR_TYPES_NFDS_T_H
+#define LLVM_LIBC_HDR_TYPES_NFDS_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/nfds_t.h"
+
+#else // overlay mode
+
+#include <poll.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_NFDS_T_H
diff --git a/libc/hdr/types/struct_pollfd.h b/libc/hdr/types/struct_pollfd.h
new file mode 100644
index 00000000000000..efec6fc80ac109
--- /dev/null
+++ b/libc/hdr/types/struct_pollfd.h
@@ -0,0 +1,23 @@
+//===-- Definition of struct pollfd ---------------------------------------===//
+//
+// 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_HDR_TYPES_STRUCT_POLLFD_H
+#define LLVM_LIBC_HDR_TYPES_STRUCT_POLLFD_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/struct_pollfd.h"
+
+#else // overlay mode
+
+#include <poll.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_STRUCT_POLLFD_H
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index e5ceea360d3965..624f83a4ec2834 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -704,6 +704,16 @@ add_header_macro(
     .llvm-libc-types.struct_lconv
 )
 
+add_header_macro(
+  poll
+  ../libc/include/poll.yaml
+  poll.h
+  DEPENDS
+    .llvm-libc-types.struct_pollfd
+    .llvm-libc-types.nfds_t
+    .llvm-libc-macros.poll-macros
+  )
+
 if(NOT LLVM_LIBC_FULL_BUILD)
   # We don't install headers in non-fullbuild mode.
   return()
diff --git a/libc/include/llvm-libc-macros/CMakeLists.txt b/libc/include/llvm-libc-macros/CMakeLists.txt
index 9d5d9f65442889..441b550543f67d 100644
--- a/libc/include/llvm-libc-macros/CMakeLists.txt
+++ b/libc/include/llvm-libc-macros/CMakeLists.txt
@@ -321,3 +321,9 @@ add_macro_header(
   HDR
     pthread-macros.h
 )
+
+add_macro_header(
+  poll-macros
+  HDR
+    poll-macros.h
+)
diff --git a/libc/include/llvm-libc-macros/linux/CMakeLists.txt b/libc/include/llvm-libc-macros/linux/CMakeLists.txt
index 461b190c02eacf..61da55eabd40ba 100644
--- a/libc/include/llvm-libc-macros/linux/CMakeLists.txt
+++ b/libc/include/llvm-libc-macros/linux/CMakeLists.txt
@@ -10,6 +10,12 @@ add_header(
     fcntl-macros.h
 )
 
+add_header(
+  poll-macros
+  HDR
+    poll-macros.h
+)
+
 add_header(
   sched_macros
   HDR
diff --git a/libc/include/llvm-libc-macros/linux/poll-macros.h b/libc/include/llvm-libc-macros/linux/poll-macros.h
new file mode 100644
index 00000000000000..6c6d026728d3fa
--- /dev/null
+++ b/libc/include/llvm-libc-macros/linux/poll-macros.h
@@ -0,0 +1,65 @@
+//===-- Macros defined in poll.h header file ------------------------------===//
+//
+// 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_MACROS_LINUX_POLL_MACROS_H
+#define LLVM_LIBC_MACROS_LINUX_POLL_MACROS_H
+
+// From asm-generic/poll.h, redefined here to avoid redeclaring struct pollfd.
+#ifndef POLLIN
+#define POLLIN          0x0001
+#endif
+
+#ifndef POLLPRI
+#define POLLPRI         0x0002
+#endif
+
+#ifndef POLLOUT
+#define POLLOUT         0x0004
+#endif
+
+#ifndef POLLERR
+#define POLLERR         0x0008
+#endif
+
+#ifndef POLLHUP
+#define POLLHUP         0x0010
+#endif
+
+#ifndef POLLNVAL
+#define POLLNVAL        0x0020
+#endif
+
+#ifndef POLLRDNORM
+#define POLLRDNORM      0x0040
+#endif
+
+#ifndef POLLRDBAND
+#define POLLRDBAND      0x0080
+#endif
+
+#ifndef POLLWRNORM
+#define POLLWRNORM      0x0100
+#endif
+
+#ifndef POLLWRBAND
+#define POLLWRBAND      0x0200
+#endif
+
+#ifndef POLLMSG
+#define POLLMSG         0x0400
+#endif
+
+#ifndef POLLREMOVE
+#define POLLREMOVE      0x1000
+#endif
+
+#ifndef POLLRDHUP
+#define POLLRDHUP       0x2000
+#endif
+
+#endif // LLVM_LIBC_MACROS_LINUX_POLL_MACROS_H
diff --git a/libc/include/llvm-libc-macros/poll-macros.h b/libc/include/llvm-libc-macros/poll-macros.h
new file mode 100644
index 00000000000000..52b59a978a21f7
--- /dev/null
+++ b/libc/include/llvm-libc-macros/poll-macros.h
@@ -0,0 +1,16 @@
+//===-- Macros defined in poll.h header file ------------------------------===//
+//
+// 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_MACROS_POLL_MACROS_H
+#define LLVM_LIBC_MACROS_POLL_MACROS_H
+
+#ifdef __linux__
+#include "linux/poll-macros.h"
+#endif
+
+#endif // LLVM_LIBC_MACROS_POLL_MACROS_H
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 6cbaa1ac0b30c3..9e8d2f818d4ed4 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -44,6 +44,7 @@ add_header(jmp_buf HDR jmp_buf.h)
 add_header(mbstate_t HDR mbstate_t.h)
 add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h DEPENDS .__futex_word .__mutex_type)
+add_header(nfds_t HDR nfds_t.h)
 add_header(nlink_t HDR nlink_t.h)
 add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)
@@ -67,14 +68,15 @@ else()
 endif()
 add_header(stack_t HDR stack_t.h DEPENDS .size_t)
 add_header(suseconds_t HDR suseconds_t.h)
+add_header(struct_dirent HDR struct_dirent.h DEPENDS .ino_t .off_t)
+add_header(struct_f_owner_ex HDR struct_f_owner_ex.h DEPENDS .pid_t)
 add_header(struct_flock HDR struct_flock.h DEPENDS .off_t .pid_t)
 add_header(struct_flock64 HDR struct_flock64.h DEPENDS .off64_t .pid_t)
-add_header(struct_f_owner_ex HDR struct_f_owner_ex.h DEPENDS .pid_t)
-add_header(struct_timeval HDR struct_timeval.h DEPENDS .suseconds_t .time_t)
+add_header(struct_pollfd HDR struct_pollfd.h)
 add_header(struct_rlimit HDR struct_rlimit.h DEPENDS .rlim_t)
-add_header(struct_rusage HDR struct_rusage.h DEPENDS .struct_timeval)
-add_header(struct_dirent HDR struct_dirent.h DEPENDS .ino_t .off_t)
 add_header(struct_sched_param HDR struct_sched_param.h)
+add_header(struct_timeval HDR struct_timeval.h DEPENDS .suseconds_t .time_t)
+add_header(struct_rusage HDR struct_rusage.h DEPENDS .struct_timeval)
 add_header(union_sigval HDR union_sigval.h)
 add_header(siginfo_t HDR siginfo_t.h DEPENDS .union_sigval .pid_t .uid_t .clock_t)
 add_header(sig_atomic_t HDR sig_atomic_t.h)
diff --git a/libc/include/llvm-libc-types/nfds_t.h b/libc/include/llvm-libc-types/nfds_t.h
new file mode 100644
index 00000000000000..c0abccee8a7da9
--- /dev/null
+++ b/libc/include/llvm-libc-types/nfds_t.h
@@ -0,0 +1,14 @@
+//===-- Definition of type nfds_t -----------------------------------------===//
+//
+// 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_TYPES_NFDS_T_H
+#define LLVM_LIBC_TYPES_NFDS_T_H
+
+typedef unsigned int nfds_t;
+
+#endif // LLVM_LIBC_TYPES_NFDS_T_H
diff --git a/libc/include/llvm-libc-types/struct_pollfd.h b/libc/include/llvm-libc-types/struct_pollfd.h
new file mode 100644
index 00000000000000..80abc8e76efc64
--- /dev/null
+++ b/libc/include/llvm-libc-types/struct_pollfd.h
@@ -0,0 +1,18 @@
+//===-- Definition of type struct pollfd ----------------------------------===//
+//
+// 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_TYPES_STRUCT_POLLFD_H
+#define LLVM_LIBC_TYPES_STRUCT_POLLFD_H
+
+struct pollfd {
+  int fd;
+  short events;
+  short revents;
+};
+
+#endif // LLVM_LIBC_TYPES_STRUCT_POLLFD_H
diff --git a/libc/include/poll.yaml b/libc/include/poll.yaml
new file mode 100644
index 00000000000000..399cc91854cdf6
--- /dev/null
+++ b/libc/include/poll.yaml
@@ -0,0 +1,16 @@
+header: poll.h
+header_template: poll.h.def
+macros: []
+types:
+  - type_name: struct_pollfd
+  - type_name: nfds_t
+enums: []
+functions:
+  - name: poll
+    standards:
+      - posix
+    return_type: int
+    arguments:
+      - type: struct pollfd *
+      - type: nfds_t
+      - type: int
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
index 41183429f67a75..19a354ceee4b65 100644
--- a/libc/src/CMakeLists.txt
+++ b/libc/src/CMakeLists.txt
@@ -20,6 +20,7 @@ add_subdirectory(unistd)
 if(${LIBC_TARGET_OS} STREQUAL "linux")
   add_subdirectory(dirent)
   add_subdirectory(fcntl)
+  add_subdirectory(poll)
   add_subdirectory(pthread)
   add_subdirectory(sched)
   add_subdirectory(sys)
diff --git a/libc/src/poll/linux/CMakeLists.txt b/libc/src/poll/linux/CMakeLists.txt
new file mode 100644
index 00000000000000..f12589381f1638
--- /dev/null
+++ b/libc/src/poll/linux/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_entrypoint_object(
+  poll
+  SRCS
+    poll.cpp
+  HDRS
+    ../poll.h
+  DEPENDS
+    libc.hdr.types.nfds_t
+    libc.hdr.types.struct_pollfd
+    libc.include.poll
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
diff --git a/libc/src/poll/linux/poll.cpp b/libc/src/poll/linux/poll.cpp
new file mode 100644
index 00000000000000..4e3ec6de6d6b49
--- /dev/null
+++ b/libc/src/poll/linux/poll.cpp
@@ -0,0 +1,31 @@
+//===-- Implementation of poll --------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/poll/poll.h"
+
+#include "hdr/types/nfds_t.h"
+#include "hdr/types/struct_pollfd.h"
+#include "src/__support/OSUtil/syscall.h" // syscall_impl
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/errno/libc_errno.h"
+
+#include <sys/syscall.h> // SYS_poll
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, poll, (struct pollfd *fds, nfds_t nfds, int timeout)) {
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_poll, fds, nfds, timeout);
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+  return ret;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/poll/poll.h b/libc/src/poll/poll.h
new file mode 100644
index 00000000000000..5fe4c2beec1d32
--- /dev/null
+++ b/libc/src/poll/poll.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for poll ----------------------------*-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_POLL_POLL_H
+#define LLVM_LIBC_SRC_POLL_POLL_H
+
+#include "hdr/types/nfds_t.h"
+#include "hdr/types/struct_pollfd.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int poll(struct pollfd *fds, nfds_t nfds, int timeout);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif //  LLVM_LIBC_SRC_POLL_POLL_H
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
index a8f779ff651315..b7c145788c0cdc 100644
--- a/libc/test/src/CMakeLists.txt
+++ b/libc/test/src/CMakeLists.txt
@@ -77,6 +77,7 @@ add_subdirectory(inttypes)
 
 if(${LIBC_TARGET_OS} STREQUAL "linux")
   add_subdirectory(fcntl)
+  add_subdirectory(poll)
   add_subdirectory(sched)
   add_subdirectory(sys)
   add_subdirectory(termios)
diff --git a/libc/test/src/poll/poll_test.cpp b/libc/test/src/poll/poll_test.cpp
new file mode 100644
index 00000000000000..5519dd5607bb5e
--- /dev/null
+++ b/libc/test/src/poll/poll_test.cpp
@@ -0,0 +1,18 @@
+//===-- Unittests for poll ------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/errno/libc_errno.h"
+#include "src/poll/poll.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcPollTest, SmokeTest) {
+  LIBC_NAMESPACE::libc_errno = 0;
+  int ret = LIBC_NAMESPACE::poll(nullptr, 0, 0);
+  ASSERT_ERRNO_SUCCESS();
+  ASSERT_EQ(0, ret);
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/125118

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