Kernel: Add support for mkfifo{,at} mkdir at

Opening FIFOs still dont work as expected but at least you can create
them now :D

kernel/include/kernel/Process.h

@@ -106,7 +106,8 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_read(int fd, void* buffer, size_t count);
 		BAN::ErrorOr<long> sys_write(int fd, const void* buffer, size_t count);
 		BAN::ErrorOr<long> sys_access(const char* path, int amode);
-		BAN::ErrorOr<long> sys_create_dir(const char*, mode_t);
+		BAN::ErrorOr<long> sys_mkdirat(int fd, const char* path, mode_t);
+		BAN::ErrorOr<long> sys_mkfifoat(int fd, const char* path, mode_t);
 		BAN::ErrorOr<long> sys_hardlinkat(int fd1, const char* path1, int fd2, const char* path2, int flag);
 		BAN::ErrorOr<long> sys_renameat(int oldfd, const char* old, int newfd, const char* _new);
 		BAN::ErrorOr<long> sys_unlinkat(int fd, const char* path, int flag);

kernel/kernel/Process.cpp

@@ -1302,7 +1302,7 @@ namespace Kernel
 		return 0;
 	}
 
-	BAN::ErrorOr<long> Process::sys_create_dir(const char* user_path, mode_t mode)
+	BAN::ErrorOr<long> Process::sys_mkdirat(int fd, const char* user_path, mode_t mode)
 	{
 		char path[PATH_MAX];
 		TRY(read_string_from_user(user_path, path, PATH_MAX));
@@ -1313,12 +1313,29 @@ namespace Kernel
 			uid_gid_t { m_credentials.euid(), m_credentials.egid() };
 		});
 
-		auto [parent, file_name] = TRY(find_parent_file(AT_FDCWD, path, O_WRONLY));
+		auto [parent, file_name] = TRY(find_parent_file(fd, path, O_WRONLY));
 		TRY(parent.inode->create_directory(file_name, (mode & 0777) | Inode::Mode::IFDIR, uid, gid));
 
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_mkfifoat(int fd, const char* user_path, mode_t mode)
+	{
+		char path[PATH_MAX];
+		TRY(read_string_from_user(user_path, path, PATH_MAX));
+
+		struct uid_gid_t { uid_t uid; gid_t gid; };
+		const auto [uid, gid] = ({
+			LockGuard _(m_process_lock);
+			uid_gid_t { m_credentials.euid(), m_credentials.egid() };
+		});
+
+		auto [parent, file_name] = TRY(find_parent_file(fd, path, O_WRONLY));
+		TRY(parent.inode->create_file(file_name, (mode & 0777) | Inode::Mode::IFIFO, uid, gid));
+
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_hardlinkat(int fd1, const char* user_path1, int fd2, const char* user_path2, int flag)
 	{
 		char path1[PATH_MAX];
@@ -1415,12 +1432,11 @@ namespace Kernel
 		TRY(read_string_from_user(user_path1, path1, PATH_MAX));
 
 		char path2[PATH_MAX];
-		if (user_path2 != nullptr)
+		TRY(read_string_from_user(user_path2, path2, PATH_MAX));
-			TRY(read_string_from_user(user_path2, path2, PATH_MAX));
 
-		TRY(create_file(fd, user_path2 ? path2 : nullptr, 0777 | Inode::Mode::IFLNK));
+		TRY(create_file(fd, path2, 0777 | Inode::Mode::IFLNK));
 
-		auto symlink = TRY(find_file(fd, user_path2 ? path2 : nullptr, O_NOFOLLOW));
+		auto symlink = TRY(find_file(fd, path2, O_NOFOLLOW));
 		TRY(symlink.inode->set_link_target(path1));
 
 		return 0;

userspace/libraries/LibC/include/sys/syscall.h

@@ -52,7 +52,8 @@ __BEGIN_DECLS
 	O(SYS_TTY_CTRL,			tty_ctrl)		\
 	O(SYS_POWEROFF,			poweroff)		\
 	O(SYS_FCHMODAT,			fchmodat)		\
-	O(SYS_CREATE_DIR,		create_dir)		\
+	O(SYS_MKDIRAT,			mkdirat)		\
+	O(SYS_MKFIFOAT,			mkfifoat)		\
 	O(SYS_UNLINKAT,			unlinkat) 		\
 	O(SYS_READLINKAT,		readlinkat)		\
 	O(SYS_MSYNC,			msync)			\

userspace/libraries/LibC/sys/stat.cpp

@@ -52,28 +52,27 @@ mode_t umask(mode_t cmask)
 
 int mkdir(const char* path, mode_t mode)
 {
-	return syscall(SYS_CREATE_DIR, path, __UMASKED_MODE(mode));
+	return mkdirat(AT_FDCWD, path, mode);
+}
+
+int mkdirat(int fd, const char* path, mode_t mode)
+{
+	return syscall(SYS_MKDIRAT, fd, path, __UMASKED_MODE(mode));
 }
 
 int mkfifo(const char* path, mode_t mode)
 {
-	(void)path; (void)mode;
+	return mkfifoat(AT_FDCWD, path, mode);
-	dwarnln("TODO: mkfifo");
-	return -1;
 }
 
 int mkfifoat(int fd, const char* path, mode_t mode)
 {
-	(void)fd; (void)path; (void)mode;
+	return syscall(SYS_MKFIFOAT, fd, path, __UMASKED_MODE(mode));
-	dwarnln("TODO: mkfifoat");
-	return -1;
 }
 
 int mknod(const char* path, mode_t mode, dev_t dev)
 {
-	(void)path; (void)mode; (void)dev;
+	return mknodat(AT_FDCWD, path, mode, dev);
-	dwarnln("TODO: mknod");
-	return -1;
 }
 
 int mknodat(int fd, const char* path, mode_t mode, dev_t dev)