From 5fca5c774a1af6898affa22ea2009358679649db Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 31 Jul 2024 23:25:11 +0300
Subject: [PATCH] LibC: Implement umask()

---
 userspace/libraries/LibC/fcntl.cpp          |  6 +++---
 userspace/libraries/LibC/include/sys/stat.h |  3 +++
 userspace/libraries/LibC/sys/stat.cpp       | 11 ++++++++++-
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/userspace/libraries/LibC/fcntl.cpp b/userspace/libraries/LibC/fcntl.cpp
index 288fa0aa12..bbfc84597f 100644
--- a/userspace/libraries/LibC/fcntl.cpp
+++ b/userspace/libraries/LibC/fcntl.cpp
@@ -6,7 +6,7 @@
 
 int creat(const char* path, mode_t mode)
 {
-	return syscall(SYS_CREATE, path, S_IFREG | mode);
+	return syscall(SYS_CREATE, path, S_IFREG | __UMASKED_MODE(mode));
 }
 
 int open(const char* path, int oflag, ...)
@@ -16,7 +16,7 @@ int open(const char* path, int oflag, ...)
 	mode_t mode = va_arg(args, mode_t);
 	va_end(args);
 
-	return syscall(SYS_OPEN, path, oflag, mode);
+	return syscall(SYS_OPEN, path, oflag, __UMASKED_MODE(mode));
 }
 
 int openat(int fd, const char* path, int oflag, ...)
@@ -26,7 +26,7 @@ int openat(int fd, const char* path, int oflag, ...)
 	mode_t mode = va_arg(args, mode_t);
 	va_end(args);
 
-	return syscall(SYS_OPENAT, fd, path, oflag, mode);
+	return syscall(SYS_OPENAT, fd, path, oflag, __UMASKED_MODE(mode));
 }
 
 int fcntl(int fildes, int cmd, ...)
diff --git a/userspace/libraries/LibC/include/sys/stat.h b/userspace/libraries/LibC/include/sys/stat.h
index 1a8eb393e9..b12d03b9a4 100644
--- a/userspace/libraries/LibC/include/sys/stat.h
+++ b/userspace/libraries/LibC/include/sys/stat.h
@@ -42,6 +42,9 @@ struct stat
 #define st_ctime st_ctim.tv_sec
 #define st_mtime st_mtim.tv_sec
 
+extern mode_t __umask;
+#define __UMASKED_MODE(mode) ((mode) & ~__umask)
+
 #define S_IRWXU		00700
 #define S_IRUSR		00400
 #define S_IWUSR		00200
diff --git a/userspace/libraries/LibC/sys/stat.cpp b/userspace/libraries/LibC/sys/stat.cpp
index 923e6dec1f..8e2a270a88 100644
--- a/userspace/libraries/LibC/sys/stat.cpp
+++ b/userspace/libraries/LibC/sys/stat.cpp
@@ -4,6 +4,8 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+mode_t __umask = 0;
+
 int chmod(const char* path, mode_t mode)
 {
 	return syscall(SYS_CHMOD, path, mode);
@@ -29,7 +31,14 @@ int stat(const char* __restrict path, struct stat* __restrict buf)
 	return syscall(SYS_STAT, path, buf, 0);
 }
 
+mode_t umask(mode_t cmask)
+{
+	mode_t old = __umask;
+	__umask = cmask;
+	return old;
+}
+
 int mkdir(const char* path, mode_t mode)
 {
-	return syscall(SYS_CREATE_DIR, path, mode);
+	return syscall(SYS_CREATE_DIR, path, __UMASKED_MODE(mode));
 }