diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index 91d601d50a711..4dcb5a2ea696a 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -414,6 +414,7 @@ add_header_macro(
     .llvm-libc-macros.signal_macros
     .llvm-libc-types.pid_t
     .llvm-libc-types.sig_atomic_t
+    .llvm-libc-types.sig_t
     .llvm-libc-types.sighandler_t
     .llvm-libc-types.siginfo_t
     .llvm-libc-types.sigset_t
diff --git a/libc/include/llvm-libc-macros/linux/signal-macros.h b/libc/include/llvm-libc-macros/linux/signal-macros.h
index e9fff447f9086..8532c423c395f 100644
--- a/libc/include/llvm-libc-macros/linux/signal-macros.h
+++ b/libc/include/llvm-libc-macros/linux/signal-macros.h
@@ -150,5 +150,9 @@
 #define SI_TIMER (-2)   // Expiration of a timer set by timer_settime()
 #define SI_ASYNCIO (-4) // Completion of an synchronous I/O request
 #define SI_MESGQ (-3)   // Arrival of a message on an empty message queue
+#define SI_SIGIO (-5)   // Queued SIGIO, on older versions of Linux
+#define SI_TKILL (-6)   // Sent by tkill or tgkill
+#define SI_ASYNCNL (-60) // Async name lookup completion
+#define SI_KERNEL 128    // Sent by the kernel
 
 #endif // LLVM_LIBC_MACROS_LINUX_SIGNAL_MACROS_H
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 1c999bfd0b857..69d62619f7979 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -122,6 +122,7 @@ add_header(rlim_t HDR rlim_t.h)
 add_header(sem_t HDR sem_t.h DEPENDS .__futex_word)
 add_header(time_t HDR time_t_64.h DEST_HDR time_t.h)
 add_header(timer_t HDR timer_t.h)
+add_header(sig_t HDR sig_t.h)
 add_header(sighandler_t HDR sighandler_t.h)
 add_header(stack_t HDR stack_t.h DEPENDS .size_t)
 add_header(suseconds_t HDR suseconds_t.h)
diff --git a/libc/include/llvm-libc-types/sig_t.h b/libc/include/llvm-libc-types/sig_t.h
new file mode 100644
index 0000000000000..ad6b1aeb5617c
--- /dev/null
+++ b/libc/include/llvm-libc-types/sig_t.h
@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+/// Definition of sig_t type.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_SIG_T_H
+#define LLVM_LIBC_TYPES_SIG_T_H
+
+// BSD type for signal handlers.
+typedef void (*sig_t)(int);
+
+#endif // LLVM_LIBC_TYPES_SIG_T_H
diff --git a/libc/include/llvm-libc-types/siginfo_t.h b/libc/include/llvm-libc-types/siginfo_t.h
index 20fdd461bb6df..67366e40b1ebc 100644
--- a/libc/include/llvm-libc-types/siginfo_t.h
+++ b/libc/include/llvm-libc-types/siginfo_t.h
@@ -33,7 +33,7 @@ typedef struct {
     /* POSIX.1b timers */
     struct {
       int si_tid;             /* timer id */
-      int _overrun;           /* overrun count */
+      int si_overrun;         /* overrun count */
       union sigval si_sigval; /* same as below */
     } _timer;
 
diff --git a/libc/include/signal.yaml b/libc/include/signal.yaml
index 7ab557875af71..307bbfedbec01 100644
--- a/libc/include/signal.yaml
+++ b/libc/include/signal.yaml
@@ -23,7 +23,12 @@ macros:
 types:
   - type_name: pid_t
   - type_name: sig_atomic_t
+  - type_name: sig_t
+    standards:
+      - bsd
   - type_name: sighandler_t
+    standards:
+      - gnu
   - type_name: siginfo_t
   - type_name: sigset_t
   - type_name: stack_t