From 31bcad25352358be0090c59603e1dcec78c92708 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Sun, 1 Jun 2025 05:07:15 +0300
Subject: [PATCH] LibC: Implement truncate

---
 kernel/include/kernel/Process.h                |  2 +-
 kernel/kernel/Process.cpp                      |  2 +-
 userspace/libraries/LibC/include/sys/syscall.h |  2 +-
 userspace/libraries/LibC/unistd.cpp            | 12 +++++++++++-
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 4499960802..cbd1d78819 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -150,7 +150,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_seek(int fd, off_t offset, int whence);
 		BAN::ErrorOr<long> sys_tell(int fd);
 
-		BAN::ErrorOr<long> sys_truncate(int fd, off_t length);
+		BAN::ErrorOr<long> sys_ftruncate(int fd, off_t length);
 
 		BAN::ErrorOr<long> sys_fsync(int fd);
 
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index 54d9810b54..a83e526964 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -1856,7 +1856,7 @@ namespace Kernel
 		return TRY(m_open_file_descriptors.tell(fd));
 	}
 
-	BAN::ErrorOr<long> Process::sys_truncate(int fd, off_t length)
+	BAN::ErrorOr<long> Process::sys_ftruncate(int fd, off_t length)
 	{
 		TRY(m_open_file_descriptors.truncate(fd, length));
 		return 0;
diff --git a/userspace/libraries/LibC/include/sys/syscall.h b/userspace/libraries/LibC/include/sys/syscall.h
index 7a15417cf4..c3c77c819f 100644
--- a/userspace/libraries/LibC/include/sys/syscall.h
+++ b/userspace/libraries/LibC/include/sys/syscall.h
@@ -74,7 +74,7 @@ __BEGIN_DECLS
 	O(SYS_LISTEN,			listen)			\
 	O(SYS_PSELECT,			pselect)		\
 	O(SYS_PPOLL,			ppoll)			\
-	O(SYS_TRUNCATE,			truncate)		\
+	O(SYS_FTRUNCATE,		ftruncate)		\
 	O(SYS_SMO_CREATE,		smo_create)		\
 	O(SYS_SMO_DELETE,		smo_delete)		\
 	O(SYS_SMO_MAP,			smo_map)		\
diff --git a/userspace/libraries/LibC/unistd.cpp b/userspace/libraries/LibC/unistd.cpp
index 48f2172071..68d4d3646a 100644
--- a/userspace/libraries/LibC/unistd.cpp
+++ b/userspace/libraries/LibC/unistd.cpp
@@ -157,9 +157,19 @@ off_t lseek(int fildes, off_t offset, int whence)
 	return syscall(SYS_SEEK, fildes, offset, whence);
 }
 
+int truncate(const char* path, off_t length)
+{
+	const int fd = open(path, O_WRONLY);
+	if (fd == -1)
+		return -1;
+	int ret = ftruncate(fd, length);
+	close(fd);
+	return ret;
+}
+
 int ftruncate(int fildes, off_t length)
 {
-	return syscall(SYS_TRUNCATE, fildes, length);
+	return syscall(SYS_FTRUNCATE, fildes, length);
 }
 
 int fsync(int fildes)