[libc] Add sigfillset and sigdelset

[abrachet]

Summary

Add's sigfillset and sigdelset which will be used in D76676.

[sivachandra]

libc/src/signal/linux/sigdelset.cpp

19

Not a blocker but just something which struck my mind as I was reading the POSIX docs again today. POSIX doesn't seem to care about set == nullptr. We could still detect an invalid set and set a different error may be so that we don't step on POSIX's way of setting EINVAL for a bad signum. May be EFAULT? Whatever we do, we need to do it consistently across all of these related functions. Since sigaddset already has similar code, we can keep it as is here for now.

[abrachet]

libc/src/signal/linux/sigdelset.cpp

19

Sounds good to use EFAULT here and the other sig*set functions when the set is null in another patch.

libc/src/signal/linux/CMakeLists.txt

SRCS
     signal.cpp
   HDRS
     signal.h
     ../signal.h
   DEPENDS
     sigaction
     signal_h
 )
+
+add_entrypoint_object(
+  sigfillset
+  SRCS
+    sigfillset.cpp
+  HDRS
+    signal.h
+    ../sigfillset.h
+  DEPENDS
+    __errno_location
+    errno_h
+    signal_h
+)
+
+add_entrypoint_object(
+  sigdelset
+  SRCS
+    sigdelset.cpp
+  HDRS
+    signal.h
+    ../sigdelset.h
+  DEPENDS
+    __errno_location
+    errno_h
+    signal_h
+)

libc/src/signal/linux/sigdelset.cpp

+//===----------------- Linux implementation of sigdelset ------------------===//
+//
+// 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/sigdelset.h"
+#include "include/errno.h"
+#include "src/errno/llvmlibc_errno.h"
+#include "src/signal/linux/signal.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+int LLVM_LIBC_ENTRYPOINT(sigdelset)(sigset_t *set, int signum) {
+  if (!set || (unsigned)(signum - 1) >= (8 * sizeof(sigset_t))) {
+    llvmlibc_errno = EINVAL;
+    return -1;
+  }
+  auto *sigset = reinterpret_cast<__llvm_libc::Sigset *>(set);
+  sigset->delset(signum);
+  return 0;
+}
+
+} // namespace __llvm_libc

libc/src/signal/linux/sigfillset.cpp

+//===----------------- Linux implementation of sigfillset -----------------===//
+//
+// 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/sigfillset.h"
+#include "include/errno.h"
+#include "src/errno/llvmlibc_errno.h"
+#include "src/signal/linux/signal.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+int LLVM_LIBC_ENTRYPOINT(sigfillset)(sigset_t *set) {
+  if (!set) {
+    llvmlibc_errno = EINVAL;
+    return -1;
+  }
+  auto *sigset = reinterpret_cast<__llvm_libc::Sigset *>(set);
+  *sigset = __llvm_libc::Sigset::fullset();
+  return 0;
+}
+
+} // namespace __llvm_libc

libc/src/signal/linux/signal.h

 // Using this internally defined type will make it easier in the future to port
 // to different architectures.
 struct Sigset {
   sigset_t nativeSigset;
 
   constexpr static Sigset fullset() { return {-1UL}; }
   constexpr static Sigset emptySet() { return {0}; }
 
-  constexpr void addset(int signal) {
-    nativeSigset |= (1L << (signal - 1));
-  }
+  constexpr void addset(int signal) { nativeSigset |= (1L << (signal - 1)); }
+
+  constexpr void delset(int signal) { nativeSigset &= ~(1L << (signal - 1)); }
 
   operator sigset_t() const { return nativeSigset; }
 };
 
 constexpr static Sigset all = Sigset::fullset();
 
 static inline int block_all_signals(Sigset &set) {
   sigset_t nativeSigset = all;
   sigset_t oldSet = set;
   int ret = __llvm_libc::syscall(SYS_rt_sigprocmask, SIG_BLOCK, &nativeSigset,
                                  &oldSet, sizeof(sigset_t));
   set = {oldSet};
   return ret;
 }
 
 static inline int restore_signals(const Sigset &set) {
   sigset_t nativeSigset = set;
-  return __llvm_libc::syscall(SYS_rt_sigprocmask, SIG_SETMASK,
-                              &nativeSigset, nullptr,
-                              sizeof(sigset_t));
+  return __llvm_libc::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &nativeSigset,
+                              nullptr, sizeof(sigset_t));
 }
 
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_SIGNAL_LINUX_SIGNAL_H

libc/src/signal/sigdelset.h

+//===------------- Implementation header for sigdelset ---------*- 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_SIGDELSET_H
+#define LLVM_LIBC_SRC_SIGNAL_SIGDELSET_H
+
+#include "include/signal.h"
+
+namespace __llvm_libc {
+
+int sigdelset(sigset_t *set, int signum);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_SIGNAL_SIGDELSET_H

libc/src/signal/sigfillset.h

+//===------------- Implementation header for sigfillset --------*- 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_SIGFILLSET_H
+#define LLVM_LIBC_SRC_SIGNAL_SIGFILLSET_H
+
+#include "include/signal.h"
+
+namespace __llvm_libc {
+
+int sigfillset(sigset_t *set);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_SIGNAL_SIGFILLSET_H

libc/test/src/signal/CMakeLists.txt

add_libc_unittest(
   DEPENDS
     signal
     signal_h
     sigaction
     raise
     __errno_location
     errno_h
 )
+
+add_libc_unittest(
+  sigfillset_test
+  SUITE
+    libc_signal_unittests
+  SRCS
+    sigfillset_test.cpp
+  DEPENDS
+    sigfillset
+    sigprocmask
+    signal_h
+    raise
+    errno_h
+    __errno_location
+)
+
+add_libc_unittest(
+  sigdelset_test
+  SUITE
+    libc_signal_unittests
+  SRCS
+    sigdelset_test.cpp
+  DEPENDS
+    sigdelset
+    sigfillset
+    sigprocmask
+    signal_h
+    raise
+    errno_h
+    __errno_location
+)

libc/test/src/signal/sigdelset_test.cpp

+//===--------------------- Unittests for sigdelset ------------------------===//
+//
+// 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 "include/errno.h"
+#include "include/signal.h"
+#include "src/signal/raise.h"
+#include "src/signal/sigdelset.h"
+#include "src/signal/sigfillset.h"
+#include "src/signal/sigprocmask.h"
+
+#include "utils/UnitTest/ErrnoSetterMatcher.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(Sigdelset, Invalid) {
+  using __llvm_libc::testing::ErrnoSetterMatcher::Fails;
+  // Invalid set.
+  EXPECT_THAT(__llvm_libc::sigdelset(nullptr, SIGUSR1), Fails(EINVAL));
+
+  sigset_t set;
+  // Valid set, invalid signum.
+  EXPECT_THAT(__llvm_libc::sigdelset(&set, -1), Fails(EINVAL));
+}
+
+TEST(Sigdelset, UnblockOne) {
+  using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
+  sigset_t set;
+  EXPECT_THAT(__llvm_libc::sigfillset(&set), Succeeds());
+  EXPECT_THAT(__llvm_libc::sigdelset(&set, SIGUSR1), Succeeds());
+  EXPECT_THAT(__llvm_libc::sigprocmask(SIG_SETMASK, &set, nullptr), Succeeds());
+  EXPECT_DEATH([] { __llvm_libc::raise(SIGUSR1); }, SIGUSR1);
+}

libc/test/src/signal/sigfillset_test.cpp

+//===-------------------- Unittests for sigfillset ------------------------===//
+//
+// 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 "include/errno.h"
+#include "include/signal.h"
+#include "src/signal/raise.h"
+#include "src/signal/sigfillset.h"
+#include "src/signal/sigprocmask.h"
+
+#include "utils/UnitTest/ErrnoSetterMatcher.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(Sigfillset, Invalid) {
+  using __llvm_libc::testing::ErrnoSetterMatcher::Fails;
+  EXPECT_THAT(__llvm_libc::sigfillset(nullptr), Fails(EINVAL));
+}
+
+TEST(Sigfillset, BlocksAll) {
+  using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
+  sigset_t set;
+  EXPECT_THAT(__llvm_libc::sigfillset(&set), Succeeds());
+  EXPECT_THAT(__llvm_libc::sigprocmask(SIG_SETMASK, &set, nullptr), Succeeds());
+  EXPECT_EXITS([] { __llvm_libc::raise(SIGUSR1); }, 0);
+}