From f52877abb45dec86a66689dc2553af426f06d8b6 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Tue, 27 May 2025 07:13:06 +0300
Subject: [PATCH] LibC: Implement `readv` and `writev`

---
 userspace/libraries/LibC/CMakeLists.txt |  1 +
 userspace/libraries/LibC/sys/uio.cpp    | 46 +++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 userspace/libraries/LibC/sys/uio.cpp

diff --git a/userspace/libraries/LibC/CMakeLists.txt b/userspace/libraries/LibC/CMakeLists.txt
index 01a20abb6d..707cd0230f 100644
--- a/userspace/libraries/LibC/CMakeLists.txt
+++ b/userspace/libraries/LibC/CMakeLists.txt
@@ -39,6 +39,7 @@ set(LIBC_SOURCES
 	sys/stat.cpp
 	sys/statvfs.cpp
 	sys/time.cpp
+	sys/uio.cpp
 	sys/utsname.cpp
 	sys/wait.cpp
 	syslog.cpp
diff --git a/userspace/libraries/LibC/sys/uio.cpp b/userspace/libraries/LibC/sys/uio.cpp
new file mode 100644
index 0000000000..3871d2a8e5
--- /dev/null
+++ b/userspace/libraries/LibC/sys/uio.cpp
@@ -0,0 +1,46 @@
+#include <sys/uio.h>
+#include <unistd.h>
+
+ssize_t readv(int fildes, const struct iovec* iov, int iovcnt)
+{
+	size_t result = 0;
+	for (int i = 0; i < iovcnt; i++)
+	{
+		uint8_t* base = static_cast<uint8_t*>(iov->iov_base);
+
+		size_t nread = 0;
+		while (nread < iov[i].iov_len)
+		{
+			const ssize_t ret = read(fildes, base + nread, iov[i].iov_len - nread);
+			if (ret == -1 && result == 0)
+				return -1;
+			if (ret <= 0)
+				return result;
+			nread += ret;
+		}
+		result += nread;
+	}
+	return result;
+}
+
+ssize_t writev(int fildes, const struct iovec* iov, int iovcnt)
+{
+	size_t result = 0;
+	for (int i = 0; i < iovcnt; i++)
+	{
+		const uint8_t* base = static_cast<const uint8_t*>(iov->iov_base);
+
+		size_t nwrite = 0;
+		while (nwrite < iov[i].iov_len)
+		{
+			const ssize_t ret = write(fildes, base + nwrite, iov[i].iov_len - nwrite);
+			if (ret == -1 && result == 0)
+				return -1;
+			if (ret <= 0)
+				return result;
+			nwrite += ret;
+		}
+		result += nwrite;
+	}
+	return result;
+}