lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/lib/mlibc/sysdeps/managarm/generic/time.cpp b/lib/mlibc/sysdeps/managarm/generic/time.cpp
new file mode 100644
index 0000000..468a738
--- /dev/null
+++ b/lib/mlibc/sysdeps/managarm/generic/time.cpp
@@ -0,0 +1,81 @@
+
+#include <bits/ensure.h>
+#include <time.h>
+#include <string.h>
+#include <sys/time.h>
+
+#include <hel.h>
+#include <hel-syscalls.h>
+#include <mlibc/debug.hpp>
+#include <mlibc/allocator.hpp>
+#include <mlibc/posix-pipe.hpp>
+#include <mlibc/all-sysdeps.hpp>
+
+struct TrackerPage {
+	uint64_t seqlock;
+	int32_t state;
+	int32_t padding;
+	int64_t refClock;
+	int64_t baseRealtime;
+};
+
+extern thread_local TrackerPage *__mlibc_clk_tracker_page;
+
+namespace mlibc {
+
+int sys_clock_get(int clock, time_t *secs, long *nanos) {
+	// This implementation is inherently signal-safe.
+	if(clock == CLOCK_MONOTONIC || clock == CLOCK_MONOTONIC_RAW || clock == CLOCK_MONOTONIC_COARSE) {
+		uint64_t tick;
+		HEL_CHECK(helGetClock(&tick));
+		*secs = tick / 1000000000;
+		*nanos = tick % 1000000000;
+	}else if(clock == CLOCK_REALTIME) {
+		cacheFileTable();
+
+		// Start the seqlock read.
+		auto seqlock = __atomic_load_n(&__mlibc_clk_tracker_page->seqlock, __ATOMIC_ACQUIRE);
+		__ensure(!(seqlock & 1));
+
+		// Perform the actual loads.
+		auto ref = __atomic_load_n(&__mlibc_clk_tracker_page->refClock, __ATOMIC_RELAXED);
+		auto base = __atomic_load_n(&__mlibc_clk_tracker_page->baseRealtime, __ATOMIC_RELAXED);
+
+		// Finish the seqlock read.
+		__atomic_thread_fence(__ATOMIC_ACQUIRE);
+		__ensure(__atomic_load_n(&__mlibc_clk_tracker_page->seqlock, __ATOMIC_RELAXED) == seqlock);
+
+		// Calculate the current time.
+		uint64_t tick;
+		HEL_CHECK(helGetClock(&tick));
+		__ensure(tick >= (uint64_t)__mlibc_clk_tracker_page->refClock); // TODO: Respect the seqlock!
+		tick -= ref;
+		tick += base;
+		*secs = tick / 1000000000;
+		*nanos = tick % 1000000000;
+	}else if(clock == CLOCK_PROCESS_CPUTIME_ID) {
+		mlibc::infoLogger() << "\e[31mmlibc: clock_gettime does not support the CPU time clocks"
+				"\e[39m" << frg::endlog;
+		*secs = 0;
+		*nanos = 0;
+	}else if(clock == CLOCK_BOOTTIME) {
+		mlibc::infoLogger() << "\e[31mmlibc: clock_gettime does not support CLOCK_BOOTTIME"
+				"\e[39m" << frg::endlog;
+		*secs = 0;
+		*nanos = 0;
+	}else{
+		mlibc::panicLogger() << "mlibc: Unexpected clock " << clock << frg::endlog;
+	}
+	return 0;
+}
+
+int sys_clock_getres(int clock, time_t *secs, long *nanos) {
+	(void)clock;
+	(void)secs;
+	(void)nanos;
+	mlibc::infoLogger() << "mlibc: clock_getres is a stub" << frg::endlog;
+	return 0;
+}
+
+} //namespace mlibc
+