Kernel/LibC: Implement utime* family functions

This patch adds *working*
 - utime
 - utimes
 - utimensat
 - futimens

kernel/kernel/FS/Ext2/Inode.cpp

@@ -4,6 +4,8 @@
 #include <kernel/FS/Ext2/Inode.h>
 #include <kernel/Timer/Timer.h>
 
+#include <sys/stat.h>
+
 namespace Kernel
 {
 
@@ -287,6 +289,28 @@ namespace Kernel
 		return {};
 	}
 
+	BAN::ErrorOr<void> Ext2Inode::utimens_impl(const timespec times[2])
+	{
+		const uint32_t old_times[2] {
+			m_inode.atime,
+			m_inode.mtime,
+		};
+
+		if (times[0].tv_nsec != UTIME_OMIT)
+			m_inode.atime = times[0].tv_sec;
+		if (times[1].tv_nsec != UTIME_OMIT)
+			m_inode.mtime = times[1].tv_sec;
+
+		if (auto ret = sync(); ret.is_error())
+		{
+			m_inode.atime = old_times[0];
+			m_inode.mtime = old_times[1];
+			return ret.release_error();
+		}
+
+		return {};
+	}
+
 	BAN::ErrorOr<void> Ext2Inode::fsync_impl()
 	{
 		for (size_t i = 0; i < max_used_data_block_count(); i++)

kernel/kernel/FS/Inode.cpp

@@ -231,6 +231,12 @@ namespace Kernel
 		return chown_impl(uid, gid);
 	}
 
+	BAN::ErrorOr<void> Inode::utimens(const timespec times[2])
+	{
+		LockGuard _(m_mutex);
+		return utimens_impl(times);
+	}
+
 	BAN::ErrorOr<void> Inode::fsync()
 	{
 		LockGuard _(m_mutex);

kernel/kernel/FS/TmpFS/Inode.cpp

@@ -2,6 +2,8 @@
 #include <kernel/FS/TmpFS/Inode.h>
 #include <kernel/Timer/Timer.h>
 
+#include <sys/stat.h>
+
 namespace Kernel
 {
 
@@ -90,6 +92,23 @@ namespace Kernel
 		m_fs.delete_inode(ino());
 	}
 
+	BAN::ErrorOr<void> TmpInode::chmod_impl(mode_t new_mode)
+	{
+		ASSERT(!(new_mode & Mode::TYPE_MASK));
+		m_inode_info.mode &= ~Mode::TYPE_MASK;
+		m_inode_info.mode |= new_mode;
+		return {};
+	}
+
+	BAN::ErrorOr<void> TmpInode::utimens_impl(const timespec times[2])
+	{
+		if (times[0].tv_nsec != UTIME_OMIT)
+			m_inode_info.atime = times[0];
+		if (times[1].tv_nsec != UTIME_OMIT)
+			m_inode_info.atime = times[1];
+		return {};
+	}
+
 	void TmpInode::sync()
 	{
 		m_fs.write_inode(m_ino, m_inode_info);
@@ -219,12 +238,6 @@ namespace Kernel
 		return {};
 	}
 
-	BAN::ErrorOr<void> TmpFileInode::chmod_impl(mode_t new_mode)
-	{
-		m_inode_info.mode = new_mode;
-		return {};
-	}
-
 	/* SOCKET INODE */
 	BAN::ErrorOr<BAN::RefPtr<TmpSocketInode>> TmpSocketInode::create_new(TmpFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
 	{
@@ -248,12 +261,6 @@ namespace Kernel
 	{
 	}
 
-	BAN::ErrorOr<void> TmpSocketInode::chmod_impl(mode_t new_mode)
-	{
-		m_inode_info.mode = new_mode;
-		return {};
-	}
-
 	/* SYMLINK INODE */
 
 	BAN::ErrorOr<BAN::RefPtr<TmpSymlinkInode>> TmpSymlinkInode::create_new(TmpFileSystem& fs, mode_t mode, uid_t uid, gid_t gid, BAN::StringView target)

kernel/kernel/Process.cpp

@@ -1262,6 +1262,56 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_utimensat(int fd, const char* path, const struct timespec _times[2], int flag)
+	{
+		if (flag & ~AT_SYMLINK_NOFOLLOW)
+			return BAN::Error::from_errno(EINVAL);
+		if (flag == AT_SYMLINK_NOFOLLOW)
+			flag = O_NOFOLLOW;
+
+		timespec times[2];
+		const uint64_t current_ns = SystemTimer::get().ns_since_boot();
+		times[0] = times[1] = timespec {
+			.tv_sec = static_cast<time_t>(current_ns / 1'000'000),
+			.tv_nsec = static_cast<long>(current_ns % 1'000'000),
+		};
+
+		if (_times)
+		{
+			LockGuard _(m_process_lock);
+			TRY(validate_pointer_access(_times, sizeof(timespec) * 2, false));
+			if (_times[0].tv_nsec != UTIME_NOW)
+			{
+				times[0] = _times[0];
+				if (auto ns = times[0].tv_nsec; ns != UTIME_OMIT && (ns < 0 || ns >= 1'000'000'000))
+					return BAN::Error::from_errno(EINVAL);
+			}
+			if (_times[1].tv_nsec != UTIME_NOW)
+			{
+				times[1] = _times[1];
+				if (auto ns = times[1].tv_nsec; ns != UTIME_OMIT && (ns < 0 || ns >= 1'000'000'000))
+					return BAN::Error::from_errno(EINVAL);
+			}
+		}
+
+		if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT)
+			return 0;
+
+		LockGuard _(m_process_lock);
+
+		auto inode = TRY(find_file(fd, path, flag)).inode;
+
+		if (!m_credentials.is_superuser() && inode->uid() != m_credentials.euid())
+		{
+			dwarnln("cannot chmod uid {} vs {}", inode->uid(), m_credentials.euid());
+			return BAN::Error::from_errno(EPERM);
+		}
+
+		TRY(inode->utimens(times));
+
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_socket(int domain, int type, int protocol)
 	{
 		LockGuard _(m_process_lock);