user: implement mlibc as the libc, finally.

It's finally done.. Signed-off-by: kaguya <vpshinomiya@protonmail.com>
2026-05-02 03:31:49 -04:00
parent 2fa39ad85a
commit 9a9b91c940
2387 changed files with 152741 additions and 315 deletions
@@ -0,0 +1,105 @@
+#include <dlfcn.h>
+#include <execinfo.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <unwind.h>
+
+#include <bits/ensure.h>
+#include <mlibc/debug.hpp>
+
+namespace {
+
+using UnwindBacktrace =  _Unwind_Reason_Code (*)(_Unwind_Trace_Fn, void *);
+using UnwindGetIP = _Unwind_Ptr (*)(_Unwind_Context *);
+
+frg::optional<void *> libgccHandle = frg::null_opt;
+
+UnwindBacktrace unwindBacktrace = nullptr;
+UnwindGetIP unwindGetIP = nullptr;
+
+struct UnwindState {
+	void **frames;
+	int count;
+	int current_frame = 0;
+};
+
+_Unwind_Reason_Code trace(_Unwind_Context *context, void *arg) {
+	UnwindState *state = static_cast<UnwindState *>(arg);
+
+	if (state->current_frame >= state->count)
+		return _URC_END_OF_STACK;
+
+	uintptr_t ip = unwindGetIP(context);
+
+	if (ip) {
+#if defined(__x86_64__) || defined(__i386__)
+		ip--;
+#elif defined(__aarch64__) || defined(__loongarch64)
+		ip -= 4;
+#elif defined(__riscv) || defined(__m68k__)
+		ip -= 2;
+#else
+#warning "Missing support for architecture"
+		ip--;
+#endif
+	}
+
+	state->frames[state->current_frame++] = reinterpret_cast<void *>(ip);
+	return _URC_NO_REASON;
+}
+
+} // namespace
+
+int backtrace(void **buffer, int size) {
+	if (size <= 0)
+		return 0;
+
+	if (!libgccHandle) {
+		libgccHandle = dlopen("libgcc_s.so.1", RTLD_LAZY | RTLD_LOCAL);
+		if (!libgccHandle || libgccHandle.value() == nullptr) {
+			mlibc::infoLogger() << "Failed to load libgcc_s.so.1: " << (dlerror() ? dlerror() : "") << frg::endlog;
+			return 0;
+		}
+
+		unwindBacktrace = reinterpret_cast<UnwindBacktrace>(dlsym(libgccHandle.value(), "_Unwind_Backtrace"));
+		unwindGetIP = reinterpret_cast<UnwindGetIP>(dlsym(libgccHandle.value(), "_Unwind_GetIP"));
+
+		if (!unwindBacktrace || !unwindGetIP) {
+			mlibc::infoLogger() << "Failed to find unwind functions in libgcc_s.so.1: " << dlerror() << frg::endlog;
+			return 0;
+		}
+	}
+
+	UnwindState state{buffer, size};
+	unwindBacktrace(trace, &state);
+	return state.current_frame;
+}
+
+char **backtrace_symbols(void *const *, int) {
+	__ensure(!"Not implemented");
+	__builtin_unreachable();
+}
+
+void backtrace_symbols_fd(void *const *buffer, int size, int fd) {
+	if (size <= 0 || fd < 0)
+		return;
+
+	for (int frame_num = 0; frame_num < size; frame_num++) {
+		Dl_info info;
+		if (dladdr(buffer[frame_num], &info) != 0) {
+			if (info.dli_fname != nullptr)
+				write(fd, info.dli_fname, strlen(info.dli_fname));
+
+			if (info.dli_sname != nullptr)
+				dprintf(fd, "(%s+0x%" PRIxPTR ") ", info.dli_sname,
+					reinterpret_cast<uintptr_t>(buffer[frame_num]) - reinterpret_cast<uintptr_t>(info.dli_saddr));
+			else if(info.dli_saddr)
+				dprintf(fd, "(+%p) ", info.dli_saddr);
+			else
+				dprintf(fd, "() ");
+		}
+
+		dprintf(fd, "[%p]\n", buffer[frame_num]);
+	}
+}