From bd5969fc876a10b18613302db7087ef3c40f18e1 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 7 Mar 2024 17:28:00 -0500
Subject: lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 lib/mlibc/sysdeps/lyre/generic/entry.cpp | 120 +++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 lib/mlibc/sysdeps/lyre/generic/entry.cpp

(limited to 'lib/mlibc/sysdeps/lyre/generic/entry.cpp')

diff --git a/lib/mlibc/sysdeps/lyre/generic/entry.cpp b/lib/mlibc/sysdeps/lyre/generic/entry.cpp
new file mode 100644
index 0000000..4fb0179
--- /dev/null
+++ b/lib/mlibc/sysdeps/lyre/generic/entry.cpp
@@ -0,0 +1,120 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <bits/ensure.h>
+#include <mlibc/debug.hpp>
+#include <mlibc/elf/startup.h>
+#include <mlibc/all-sysdeps.hpp>
+#include <bits/posix/posix_signal.h>
+#include <lyre/syscall.h>
+
+// defined by the POSIX library
+void __mlibc_initLocale();
+
+extern "C" uintptr_t *__dlapi_entrystack();
+
+extern char **environ;
+static mlibc::exec_stack_data __mlibc_stack_data;
+
+struct LibraryGuard {
+	LibraryGuard();
+};
+
+static LibraryGuard guard;
+
+LibraryGuard::LibraryGuard() {
+	__mlibc_initLocale();
+
+	// Parse the exec() stack.
+	mlibc::parse_exec_stack(__dlapi_entrystack(), &__mlibc_stack_data);
+	mlibc::set_startup_data(__mlibc_stack_data.argc, __mlibc_stack_data.argv,
+			__mlibc_stack_data.envp);
+}
+
+struct GPRState {
+	uint64_t ds;
+	uint64_t es;
+	uint64_t rax;
+	uint64_t rbx;
+	uint64_t rcx;
+	uint64_t rdx;
+	uint64_t rsi;
+	uint64_t rdi;
+	uint64_t rbp;
+	uint64_t r8;
+	uint64_t r9;
+	uint64_t r10;
+	uint64_t r11;
+	uint64_t r12;
+	uint64_t r13;
+	uint64_t r14;
+	uint64_t r15;
+	uint64_t err;
+	uint64_t rip;
+	uint64_t cs;
+	uint64_t rflags;
+	uint64_t rsp;
+	uint64_t ss;
+};
+
+namespace mlibc {
+	int sys_sigentry(void *sigentry) {
+		__syscall_ret ret = __syscall(27, sigentry);
+		if (ret.errno != 0)
+			return ret.errno;
+		return 0;
+	}
+
+	[[noreturn]] int sys_sigreturn(void *context, sigset_t old_mask) {
+		__syscall(30, context, old_mask);
+		__builtin_unreachable();
+	}
+}
+
+static void __mlibc_sigentry(int which, siginfo_t *siginfo,
+		void (*sa)(int, siginfo_t *, void *),
+		GPRState *ret_context, sigset_t prev_mask) {
+
+/*
+	size_t *base_ptr = (size_t *)ret_context->rbp;
+
+	mlibc::infoLogger() << "Stacktrace:" << frg::endlog;
+	mlibc::infoLogger() << "  [" << (void *)ret_context->rip << "]" << frg::endlog;
+	for (;;) {
+		size_t old_bp = base_ptr[0];
+		size_t ret_addr = base_ptr[1];
+		if (!ret_addr)
+			break;
+		size_t off;
+		mlibc::infoLogger() << "  [" << (void *)ret_addr << "]" << frg::endlog;
+		if (!old_bp)
+			break;
+		base_ptr = (size_t *)old_bp;
+	}
+*/
+
+	switch ((uintptr_t)sa) {
+		// DFL
+		case (uintptr_t)(-2):
+			mlibc::infoLogger() << "mlibc: Unhandled signal " << which << frg::endlog;
+			mlibc::sys_exit(128 + which);
+		// IGN
+		case (uintptr_t)(-3):
+			break;
+		default:
+			sa(which, siginfo, NULL);
+			break;
+	}
+
+	mlibc::sys_sigreturn(ret_context, prev_mask);
+
+	__builtin_unreachable();
+}
+
+extern "C" void __mlibc_entry(int (*main_fn)(int argc, char *argv[], char *env[])) {
+	//mlibc::sys_sigentry((void *)__mlibc_sigentry);
+
+	// TODO: call __dlapi_enter, otherwise static builds will break (see Linux sysdeps)
+	auto result = main_fn(__mlibc_stack_data.argc, __mlibc_stack_data.argv, environ);
+	exit(result);
+}
+
-- 
cgit v1.2.3