Kernel/LibC: implement chmod syscall + libc wrapper

kernel/include/kernel/FS/Ext2/Inode.h

@@ -37,6 +37,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
 		virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override;
 		virtual BAN::ErrorOr<void> truncate_impl(size_t) override;
+		virtual BAN::ErrorOr<void> chmod_impl(mode_t) override;
 
 	private:
 		uint32_t fs_block_of_data_block_index(uint32_t data_block_index);

kernel/include/kernel/FS/Inode.h

@@ -99,6 +99,7 @@ namespace Kernel
 		BAN::ErrorOr<size_t> read(off_t, BAN::ByteSpan buffer);
 		BAN::ErrorOr<size_t> write(off_t, BAN::ConstByteSpan buffer);
 		BAN::ErrorOr<void> truncate(size_t);
+		BAN::ErrorOr<void> chmod(mode_t);
 		bool has_data() const;
 
 	protected:
@@ -115,6 +116,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan)		{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan)	{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<void> truncate_impl(size_t)					{ return BAN::Error::from_errno(ENOTSUP); }
+		virtual BAN::ErrorOr<void> chmod_impl(mode_t)						{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual bool has_data_impl() const { dwarnln("nonblock not supported"); return true; }
 
 	private:

kernel/include/kernel/FS/RamFS/Inode.h

@@ -56,6 +56,8 @@ namespace Kernel
 			ASSERT((inode_info.mode & Inode::Mode::TYPE_MASK) == 0);
 		}
 
+		virtual BAN::ErrorOr<void> chmod_impl(mode_t) override;
+
 	protected:
 		RamFileSystem& m_fs;
 		FullInodeInfo m_inode_info;

kernel/include/kernel/Process.h

@@ -97,6 +97,8 @@ 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_chmod(const char*, mode_t);
+
 		BAN::ErrorOr<long> sys_pipe(int fildes[2]);
 		BAN::ErrorOr<long> sys_dup(int fildes);
 		BAN::ErrorOr<long> sys_dup2(int fildes, int fildes2);

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;

libc/include/sys/syscall.h

@@ -55,6 +55,7 @@ __BEGIN_DECLS
 #define SYS_MUNMAP 52
 #define SYS_TTY_CTRL 53
 #define SYS_POWEROFF 54
+#define SYS_CHMOD 55
 
 __END_DECLS
 

libc/sys/stat.cpp

@@ -4,6 +4,11 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+int chmod(const char* path, mode_t mode)
+{
+	return syscall(SYS_CHMOD, path, mode);
+}
+
 int fstat(int fildes, struct stat* buf)
 {
 	return syscall(SYS_FSTAT, fildes, buf);