From 77e9eadd9df78d7c26c704392256ad84b79ddd18 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Thu, 29 Oct 2020 12:52:11 +0100
Subject: [PATCH] Userland+LibC: Add "kill -l" to show all known signal
 names/numbers

---
 Libraries/LibC/signal.cpp |  9 +++++++++
 Libraries/LibC/signal.h   |  1 +
 Userland/kill.cpp         | 10 ++++++++++
 3 files changed, 20 insertions(+)

diff --git a/Libraries/LibC/signal.cpp b/Libraries/LibC/signal.cpp
index 327e33de5b5b01..a7a7ede8ba7a54 100644
--- a/Libraries/LibC/signal.cpp
+++ b/Libraries/LibC/signal.cpp
@@ -236,4 +236,13 @@ int getsignalbyname(const char* name)
     errno = EINVAL;
     return -1;
 }
+
+const char* getsignalname(int signal)
+{
+    if (signal < 0 || signal >= NSIG) {
+        errno = EINVAL;
+        return nullptr;
+    }
+    return signal_names[signal];
+}
 }
diff --git a/Libraries/LibC/signal.h b/Libraries/LibC/signal.h
index 51311691166fbb..65c98603d40ff1 100644
--- a/Libraries/LibC/signal.h
+++ b/Libraries/LibC/signal.h
@@ -76,6 +76,7 @@ int sigpending(sigset_t*);
 int sigsuspend(const sigset_t*);
 int raise(int sig);
 int getsignalbyname(const char*);
+const char* getsignalname(int);
 
 extern const char* sys_siglist[NSIG];
 
diff --git a/Userland/kill.cpp b/Userland/kill.cpp
index 76eeb4e891aa18..d1a85376a80fb5 100644
--- a/Userland/kill.cpp
+++ b/Userland/kill.cpp
@@ -46,6 +46,16 @@ int main(int argc, char** argv)
         return 1;
     }
 
+    if (argc == 2 && !strcmp(argv[1], "-l")) {
+        for (size_t i = 0; i < NSIG; ++i) {
+            if (i && !(i % 5))
+                outln("");
+            new_out("{:2}) {:10}", i, getsignalname(i));
+        }
+        outln("");
+        return 0;
+    }
+
     if (argc != 2 && argc != 3)
         print_usage_and_exit();
     unsigned signum = SIGTERM;