[libc-commits] [libc] [libc] Implement sigpending (Part of #236167) (PR #237568)

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Sat Oct 31 07:04:00 PDT 2026


llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Anshitha Yeruva (anshithayeruva)

<details>
<summary>Changes</summary>

This patch implements the POSIX sigpending function in LLVM libc, along with unit tests.

Part of #<!-- -->236167.

---
Full diff: https://github.com/llvm/llvm-project/pull/237568.diff


12 Files Affected:

- (modified) libc/config/linux/aarch64/entrypoints.txt (+1) 
- (modified) libc/config/linux/riscv/entrypoints.txt (+1) 
- (modified) libc/config/linux/x86_64/entrypoints.txt (+2-1) 
- (modified) libc/include/signal.yaml (+6) 
- (modified) libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt (+12) 
- (added) libc/src/__support/OSUtil/linux/syscall_wrappers/rt_sigpending.h (+34) 
- (modified) libc/src/signal/CMakeLists.txt (+6) 
- (modified) libc/src/signal/linux/CMakeLists.txt (+11) 
- (added) libc/src/signal/linux/sigpending.cpp (+28) 
- (added) libc/src/signal/sigpending.h (+21) 
- (modified) libc/test/src/signal/CMakeLists.txt (+17-1) 
- (added) libc/test/src/signal/sigpending_test.cpp (+47) 


``````````diff
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 09b1b9080e0874..1c712d38a35adc 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -1394,6 +1394,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.signal.sigfillset
     libc.src.signal.sigismember
     libc.src.signal.signal
+    libc.src.signal.sigpending
     libc.src.signal.sigprocmask
 
     # spawn.h entrypoints
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 69189b37ddddd4..6f9cffa65986c1 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -1580,6 +1580,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.signal.sigfillset
     libc.src.signal.sigismember
     libc.src.signal.signal
+    libc.src.signal.sigpending
     libc.src.signal.sigprocmask
 
     # spawn.h entrypoints
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 746e712ec160e6..a9651ae91a3968 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -1606,8 +1606,9 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.signal.sigfillset
     libc.src.signal.sigismember
     libc.src.signal.signal
+    libc.src.signal.sigpending
     libc.src.signal.sigprocmask
-
+    
     # spawn.h entrypoints
     libc.src.spawn.posix_spawn
     libc.src.spawn.posix_spawn_file_actions_addclose
diff --git a/libc/include/signal.yaml b/libc/include/signal.yaml
index b763da7eeb6025..e95959d9f9c05a 100644
--- a/libc/include/signal.yaml
+++ b/libc/include/signal.yaml
@@ -119,6 +119,12 @@ functions:
     arguments:
       - type: int
       - type: sighandler_t
+  - name: sigpending
+    standards:
+      - posix
+    return_type: int
+    arguments:
+      - type: sigset_t * 
   - name: sigprocmask
     standards:
       - posix
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
index 05eb6f0fa6f776..06e45d23c1e3cd 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
@@ -647,6 +647,18 @@ add_header_library(
     libc.hdr.types.sigset_t
     libc.include.sys_syscall
 )
+add_header_library(
+  rt_sigpending
+  HDRS
+    rt_sigpending.h
+  DEPENDS
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.macros.config
+    libc.hdr.types.sigset_t
+    libc.include.sys_syscall
+)
 
 add_header_library(
   raise
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/rt_sigpending.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/rt_sigpending.h
new file mode 100644
index 00000000000000..d41a1ab386bc99
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/rt_sigpending.h
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Implementation header for rt_sigpending.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_RT_SIGPENDING_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_RT_SIGPENDING_H
+
+#include "hdr/types/sigset_t.h"
+#include "src/__support/OSUtil/linux/syscall.h" // For syscall_checked
+#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> rt_sigpending(sigset_t *set) {
+  return syscall_checked<int>(SYS_rt_sigpending, set, sizeof(sigset_t));
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_RT_SIGPENDING_H
\ No newline at end of file
diff --git a/libc/src/signal/CMakeLists.txt b/libc/src/signal/CMakeLists.txt
index 8da94d1eea85fd..529815444f31ad 100644
--- a/libc/src/signal/CMakeLists.txt
+++ b/libc/src/signal/CMakeLists.txt
@@ -22,6 +22,12 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.sigaction
 )
+add_entrypoint_object(
+  sigpending
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.sigpending
+)
 
 add_entrypoint_object(
   sigaltstack
diff --git a/libc/src/signal/linux/CMakeLists.txt b/libc/src/signal/linux/CMakeLists.txt
index 77898cf9aab636..99aaec14c3805c 100644
--- a/libc/src/signal/linux/CMakeLists.txt
+++ b/libc/src/signal/linux/CMakeLists.txt
@@ -94,6 +94,17 @@ add_entrypoint_object(
     libc.src.__support.OSUtil.linux.syscall_wrappers.rt_sigprocmask
     libc.src.errno.errno
 )
+add_entrypoint_object(
+  sigpending
+  SRCS
+    sigpending.cpp
+  HDRS
+    ../sigpending.h
+  DEPENDS
+    libc.hdr.types.sigset_t
+    libc.src.__support.OSUtil.linux.syscall_wrappers.rt_sigpending
+    libc.src.errno.errno
+)
 
 add_entrypoint_object(
   pthread_sigmask
diff --git a/libc/src/signal/linux/sigpending.cpp b/libc/src/signal/linux/sigpending.cpp
new file mode 100644
index 00000000000000..4c72d2d672ecf5
--- /dev/null
+++ b/libc/src/signal/linux/sigpending.cpp
@@ -0,0 +1,28 @@
+//===-- Linux implementation of sigpending -------------------------------===//
+//
+// 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/signal/sigpending.h"
+
+#include "hdr/types/sigset_t.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/rt_sigpending.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, sigpending, (sigset_t *set)) {
+  auto result = linux_syscalls::rt_sigpending(set);
+  if (result.has_value())
+    return 0;
+
+  libc_errno = result.error();
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
\ No newline at end of file
diff --git a/libc/src/signal/sigpending.h b/libc/src/signal/sigpending.h
new file mode 100644
index 00000000000000..ef13a778eaaa83
--- /dev/null
+++ b/libc/src/signal/sigpending.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for sigpending function -----------*- 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_SIGNAL_SIGPENDING_H
+#define LLVM_LIBC_SRC_SIGNAL_SIGPENDING_H
+
+#include "hdr/types/sigset_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int sigpending(sigset_t *set);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SIGNAL_SIGPENDING_H
\ No newline at end of file
diff --git a/libc/test/src/signal/CMakeLists.txt b/libc/test/src/signal/CMakeLists.txt
index 287977e2762236..9270f33b96f035 100644
--- a/libc/test/src/signal/CMakeLists.txt
+++ b/libc/test/src/signal/CMakeLists.txt
@@ -53,7 +53,23 @@ add_libc_test(
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
 )
-
+add_libc_test(
+  sigpending_test
+  SUITE
+    libc-signal-tests
+  SRCS
+    sigpending_test.cpp
+  DEPENDS
+    libc.hdr.signal_macros
+    libc.hdr.types.sigset_t
+    libc.src.signal.raise
+    libc.src.signal.sigaddset
+    libc.src.signal.sigemptyset
+    libc.src.signal.sigismember
+    libc.src.signal.sigpending
+    libc.src.signal.sigprocmask
+    libc.test.UnitTest.ErrnoSetterMatcher
+)
 add_libc_test(
   pthread_sigmask_test
   SUITE
diff --git a/libc/test/src/signal/sigpending_test.cpp b/libc/test/src/signal/sigpending_test.cpp
new file mode 100644
index 00000000000000..70a052c9ea250b
--- /dev/null
+++ b/libc/test/src/signal/sigpending_test.cpp
@@ -0,0 +1,47 @@
+//===-- Unittests for sigpending ------------------------------------------===//
+//
+// 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/signal/sigpending.h"
+
+#include "hdr/signal_macros.h"
+#include "hdr/types/sigset_t.h"
+#include "src/signal/raise.h"
+#include "src/signal/sigaddset.h"
+#include "src/signal/sigemptyset.h"
+#include "src/signal/sigismember.h"
+#include "src/signal/sigprocmask.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+TEST(LlvmLibcSigpendingTest, NoBlockedSignals) {
+  sigset_t pending;
+  ASSERT_THAT(LIBC_NAMESPACE::sigpending(&pending), Succeeds(0));
+}
+
+TEST(LlvmLibcSigpendingTest, BlockAndRaise) {
+  // Block SIGUSR1.
+  sigset_t blockset;
+  ASSERT_EQ(LIBC_NAMESPACE::sigemptyset(&blockset), 0);
+  ASSERT_EQ(LIBC_NAMESPACE::sigaddset(&blockset, SIGUSR1), 0);
+
+  sigset_t oldset;
+  ASSERT_EQ(LIBC_NAMESPACE::sigprocmask(SIG_BLOCK, &blockset, &oldset), 0);
+
+  // Raise SIGUSR1; it should become pending since it is blocked.
+  ASSERT_EQ(LIBC_NAMESPACE::raise(SIGUSR1), 0);
+
+  // Check that SIGUSR1 is now pending.
+  sigset_t pending;
+  ASSERT_THAT(LIBC_NAMESPACE::sigpending(&pending), Succeeds(0));
+  ASSERT_EQ(LIBC_NAMESPACE::sigismember(&pending, SIGUSR1), 1);
+
+  // Restore the old signal mask.
+  ASSERT_EQ(LIBC_NAMESPACE::sigprocmask(SIG_SETMASK, &oldset, nullptr), 0);
+}
\ No newline at end of file

``````````

</details>


https://github.com/llvm/llvm-project/pull/237568


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