From 9825f7792b412f8067797fa19fd9e83a18d26682 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Mon, 15 Jun 2020 11:28:42 -0400
Subject: [PATCH] LibC: Add truncate().

Implemented in user space for now.
---
 Libraries/LibC/unistd.cpp | 13 +++++++++++++
 Libraries/LibC/unistd.h   |  1 +
 2 files changed, 14 insertions(+)

diff --git a/Libraries/LibC/unistd.cpp b/Libraries/LibC/unistd.cpp
index ec01ad1be4..75b0458639 100644
--- a/Libraries/LibC/unistd.cpp
+++ b/Libraries/LibC/unistd.cpp
@@ -553,6 +553,19 @@ int ftruncate(int fd, off_t length)
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
+int truncate(const char* path, off_t length)
+{
+    int fd = open(path, O_RDWR | O_CREAT, 0666);
+    if (fd < 0)
+        return fd;
+    int rc = ftruncate(fd, length);
+    int saved_errno = errno;
+    if (int close_rc = close(fd); close_rc < 0)
+        return close_rc;
+    errno = saved_errno;
+    return rc;
+}
+
 int gettid()
 {
     if (!s_cached_tid)
diff --git a/Libraries/LibC/unistd.h b/Libraries/LibC/unistd.h
index 86dd1c529f..1dfb4801ef 100644
--- a/Libraries/LibC/unistd.h
+++ b/Libraries/LibC/unistd.h
@@ -127,6 +127,7 @@ char* getlogin();
 int chown(const char* pathname, uid_t, gid_t);
 int fchown(int fd, uid_t, gid_t);
 int ftruncate(int fd, off_t length);
+int truncate(const char* path, off_t length);
 int halt();
 int reboot();
 int mount(int source_fd, const char* target, const char* fs_type, int flags);