Kernel/LibC: implement chmod syscall + libc wrapper

kernel/kernel/FS/Ext2/Inode.cpp

@@ -242,6 +242,16 @@ namespace Kernel
 		return {};
 	}
 
+	BAN::ErrorOr<void> Ext2Inode::chmod_impl(mode_t mode)
+	{
+		ASSERT((mode & Inode::Mode::TYPE_MASK) == 0);
+		if (m_inode.mode == mode)
+			return {};
+		m_inode.mode = (m_inode.mode & Inode::Mode::TYPE_MASK) | mode;
+		TRY(sync());
+		return {};
+	}
+
 	BAN::ErrorOr<void> Ext2Inode::list_next_inodes_impl(off_t offset, DirectoryEntryList* list, size_t list_size)
 	{
 		ASSERT(mode().ifdir());

kernel/kernel/FS/Inode.cpp

@@ -129,6 +129,14 @@ namespace Kernel
 		return truncate_impl(size);
 	}
 
+	BAN::ErrorOr<void> Inode::chmod(mode_t mode)
+	{
+		ASSERT((mode & Inode::Mode::TYPE_MASK) == 0);
+		LockGuard _(m_lock);
+		Thread::TerminateBlocker blocker(Thread::current());
+		return chmod_impl(mode);
+	}
+
 	bool Inode::has_data() const
 	{
 		LockGuard _(m_lock);

kernel/kernel/FS/RamFS/Inode.cpp

@@ -26,6 +26,14 @@ namespace Kernel
 		this->rdev = 0;
 	}
 
+
+	BAN::ErrorOr<void> RamInode::chmod_impl(mode_t mode)
+	{
+		ASSERT((mode & Inode::Mode::TYPE_MASK) == 0);
+		m_inode_info.mode = (m_inode_info.mode & Inode::Mode::TYPE_MASK) | mode;
+		return {};
+	}
+
 	/*
 
 		RAM FILE INODE
@@ -193,9 +201,9 @@ namespace Kernel
 	{
 		BAN::RefPtr<RamInode> inode;
 		if (Mode(mode).ifreg())
-			inode = TRY(RamFileInode::create(m_fs, mode, uid, gid));
+			inode = TRY(RamFileInode::create(m_fs, mode & ~Inode::Mode::TYPE_MASK, uid, gid));
 		else if (Mode(mode).ifdir())
-			inode = TRY(RamDirectoryInode::create(m_fs, ino(), mode, uid, gid));
+			inode = TRY(RamDirectoryInode::create(m_fs, ino(), mode & ~Inode::Mode::TYPE_MASK, uid, gid));
 		else
 			ASSERT_NOT_REACHED();
 

kernel/kernel/Process.cpp

@@ -733,6 +733,21 @@ namespace Kernel
 		return TRY(m_open_file_descriptors.write(fd, BAN::ByteSpan((uint8_t*)buffer, count)));
 	}
 
+	BAN::ErrorOr<long> Process::sys_chmod(const char* path, mode_t mode)
+	{
+		if (mode & S_IFMASK)
+			return BAN::Error::from_errno(EINVAL);
+
+		LockGuard _(m_lock);
+		validate_string_access(path);
+
+		auto absolute_path = TRY(absolute_path_of(path));
+		auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, O_WRONLY));
+		TRY(file.inode->chmod(mode));
+
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_pipe(int fildes[2])
 	{
 		LockGuard _(m_lock);

kernel/kernel/Syscall.cpp

@@ -199,6 +199,9 @@ namespace Kernel
 		case SYS_POWEROFF:
 			ret = Process::current().sys_poweroff((int)arg1);
 			break;
+		case SYS_CHMOD:
+			ret = Process::current().sys_chmod((const char*)arg1, (mode_t)arg2);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;