From 6fedf06150f645cc694195abe43147a833f27036 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 7 Aug 2024 17:03:26 +0300
Subject: [PATCH] LibC: Implement {sig,_,}{longjmp,setjmp}

---
 userspace/libraries/LibC/CMakeLists.txt       |  3 ++
 userspace/libraries/LibC/arch/i686/setjmp.S   | 28 +++++++++++++++++++
 userspace/libraries/LibC/arch/x86_64/setjmp.S | 23 +++++++++++++++
 userspace/libraries/LibC/include/setjmp.h     | 15 ++++++----
 userspace/libraries/LibC/setjmp.cpp           | 19 +++++++++++++
 userspace/tests/CMakeLists.txt                |  1 +
 userspace/tests/test-setjmp/CMakeLists.txt    |  8 ++++++
 userspace/tests/test-setjmp/main.cpp          | 22 +++++++++++++++
 8 files changed, 113 insertions(+), 6 deletions(-)
 create mode 100644 userspace/libraries/LibC/arch/i686/setjmp.S
 create mode 100644 userspace/libraries/LibC/arch/x86_64/setjmp.S
 create mode 100644 userspace/libraries/LibC/setjmp.cpp
 create mode 100644 userspace/tests/test-setjmp/CMakeLists.txt
 create mode 100644 userspace/tests/test-setjmp/main.cpp

diff --git a/userspace/libraries/LibC/CMakeLists.txt b/userspace/libraries/LibC/CMakeLists.txt
index 61086b3a..5a70dd51 100644
--- a/userspace/libraries/LibC/CMakeLists.txt
+++ b/userspace/libraries/LibC/CMakeLists.txt
@@ -13,6 +13,7 @@ set(LIBC_SOURCES
 	printf_impl.cpp
 	pwd.cpp
 	scanf_impl.cpp
+	setjmp.cpp
 	signal.cpp
 	stdio.cpp
 	stdlib.cpp
@@ -32,6 +33,8 @@ set(LIBC_SOURCES
 	unistd.cpp
 	icxxabi.cpp
 
+	arch/${BANAN_ARCH}/setjmp.S
+
 	../../../BAN/BAN/Assert.cpp
 )
 
diff --git a/userspace/libraries/LibC/arch/i686/setjmp.S b/userspace/libraries/LibC/arch/i686/setjmp.S
new file mode 100644
index 00000000..8b025507
--- /dev/null
+++ b/userspace/libraries/LibC/arch/i686/setjmp.S
@@ -0,0 +1,28 @@
+// int setjmp(jmp_buf env)
+.global setjmp
+setjmp:
+	movl 4(%esp), %edx
+
+	leal 4(%esp), %eax
+	movl %eax, 0(%edx)
+
+	movl (%esp), %eax
+	movl %eax, 4(%edx)
+
+	xorl %eax, %eax
+
+	ret
+
+// void longjmp(jmp_buf env, int val)
+.global longjmp
+longjmp:
+	movl 4(%esp), %edx
+
+	movl 8(%esp), %ecx
+	movl $1, %eax
+	testl %ecx, %ecx
+	cmovnzl %ecx, %eax
+
+	movl 0(%edx), %esp
+	movl 4(%edx), %ecx
+	jmp *%ecx
diff --git a/userspace/libraries/LibC/arch/x86_64/setjmp.S b/userspace/libraries/LibC/arch/x86_64/setjmp.S
new file mode 100644
index 00000000..7bebf826
--- /dev/null
+++ b/userspace/libraries/LibC/arch/x86_64/setjmp.S
@@ -0,0 +1,23 @@
+// int setjmp(jmp_buf env)
+.global setjmp
+setjmp:
+	leaq 8(%rsp), %rax
+	movq %rax, 0(%rdi)
+
+	movq (%rsp), %rax
+	movq %rax, 8(%rdi)
+
+	xorq %rax, %rax
+
+	ret
+
+// void longjmp(jmp_buf env, int val)
+.global longjmp
+longjmp:
+	movq $1, %rax
+	testq %rsi, %rsi
+	cmovnzq %rsi, %rax
+
+	movq 0(%rdi), %rsp
+	movq 8(%rdi), %rcx
+	jmp *%rcx
diff --git a/userspace/libraries/LibC/include/setjmp.h b/userspace/libraries/LibC/include/setjmp.h
index 20f76ea8..ada6e58e 100644
--- a/userspace/libraries/LibC/include/setjmp.h
+++ b/userspace/libraries/LibC/include/setjmp.h
@@ -7,13 +7,16 @@
 
 __BEGIN_DECLS
 
-typedef int jmp_buf[1];
-typedef int sigjmp_buf[1];
+typedef long jmp_buf[2];
+typedef long sigjmp_buf[2 + 1 + (sizeof(long long) / sizeof(long))];
 
-void	longjmp(jmp_buf env, int val);
-void	siglongjmp(sigjmp_buf env, int val);
-int		setjmp(jmp_buf env);
-int		sigsetjmp(sigjmp_buf env, int savemask);
+#define _longjmp longjmp
+void longjmp(jmp_buf env, int val);
+void siglongjmp(sigjmp_buf env, int val);
+
+#define _setjmp setjmp
+int setjmp(jmp_buf env);
+int sigsetjmp(sigjmp_buf env, int savemask);
 
 __END_DECLS
 
diff --git a/userspace/libraries/LibC/setjmp.cpp b/userspace/libraries/LibC/setjmp.cpp
new file mode 100644
index 00000000..9fb94cc1
--- /dev/null
+++ b/userspace/libraries/LibC/setjmp.cpp
@@ -0,0 +1,19 @@
+#include <setjmp.h>
+#include <signal.h>
+
+static_assert(sizeof(sigjmp_buf) == sizeof(jmp_buf) + sizeof(long) + sizeof(sigset_t));
+
+void siglongjmp(sigjmp_buf env, int val)
+{
+	if (env[2])
+		pthread_sigmask(SIG_SETMASK, reinterpret_cast<sigset_t*>(&env[3]), nullptr);
+	return longjmp(env, val);
+}
+
+int sigsetjmp(sigjmp_buf env, int savemask)
+{
+	env[2] = savemask;
+	if (savemask)
+		pthread_sigmask(0, nullptr, reinterpret_cast<sigset_t*>(&env[3]));
+	return setjmp(env);
+}
diff --git a/userspace/tests/CMakeLists.txt b/userspace/tests/CMakeLists.txt
index 90de8334..4d47941d 100644
--- a/userspace/tests/CMakeLists.txt
+++ b/userspace/tests/CMakeLists.txt
@@ -5,6 +5,7 @@ set(USERSPACE_TESTS
 	test-mmap-shared
 	test-mouse
 	test-popen
+	test-setjmp
 	test-sort
 	test-tcp
 	test-udp
diff --git a/userspace/tests/test-setjmp/CMakeLists.txt b/userspace/tests/test-setjmp/CMakeLists.txt
new file mode 100644
index 00000000..d6f3c185
--- /dev/null
+++ b/userspace/tests/test-setjmp/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(test-setjmp ${SOURCES})
+banan_link_library(test-setjmp libc)
+
+install(TARGETS test-setjmp OPTIONAL)
diff --git a/userspace/tests/test-setjmp/main.cpp b/userspace/tests/test-setjmp/main.cpp
new file mode 100644
index 00000000..ee15d81e
--- /dev/null
+++ b/userspace/tests/test-setjmp/main.cpp
@@ -0,0 +1,22 @@
+#include <setjmp.h>
+#include <stdio.h>
+
+jmp_buf env;
+
+void iterate()
+{
+	static volatile int count = 0;
+	if (count < 10)
+	{
+		count = count + 1;
+		longjmp(env, count);
+	}
+}
+
+int main()
+{
+	printf("start\n");
+	if (int ret = setjmp(env))
+		printf("longjmp %d\n", ret);
+	iterate();
+}