LibCore+ImageViewer: Add unlink() wrapper, use it

Author: https://github.com/juniorrantila
Commit: https://github.com/SerenityOS/serenity/commit/9a38d1de07a
Pull-request: https://github.com/SerenityOS/serenity/pull/11492

Userland/Applications/ImageViewer/main.cpp

@@ -131,10 +131,10 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
             if (msgbox_result == GUI::MessageBox::ExecCancel)
                 return;
 
-            if (unlink(widget.path().characters()) < 0) {
-                int saved_errno = errno;
+            auto unlinked_or_error = Core::System::unlink(widget.path());
+            if (unlinked_or_error.is_error()) {
                 GUI::MessageBox::show(window,
-                    String::formatted("unlink({}) failed: {}", path, strerror(saved_errno)),
+                    String::formatted("unlink({}) failed: {}", path, unlinked_or_error.error()),
                     "Delete failed",
                     GUI::MessageBox::Type::Error);
 

Userland/Libraries/LibCore/System.cpp

@@ -644,6 +644,22 @@ ErrorOr<void> rename(StringView old_path, StringView new_path)
 #endif
 }
 
+ErrorOr<void> unlink(StringView path)
+{
+    if (path.is_null())
+        return Error::from_errno(EFAULT);
+
+#ifdef __serenity__
+    int rc = syscall(SC_unlink, path.characters_without_null_termination(), path.length());
+    HANDLE_SYSCALL_RETURN_VALUE("unlink"sv, rc, {});
+#else
+    String path_string = path;
+    if (::unlink(path_string.characters()) < 0)
+        return Error::from_syscall("unlink"sv, -errno);
+    return {};
+#endif
+}
+
 ErrorOr<void> utime(StringView path, Optional<struct utimbuf> maybe_buf)
 {
     if (path.is_null())

Userland/Libraries/LibCore/System.h

@@ -98,6 +98,7 @@ ErrorOr<pid_t> fork();
 ErrorOr<int> mkstemp(Span<char> pattern);
 ErrorOr<void> fchmod(int fd, mode_t mode);
 ErrorOr<void> rename(StringView old_path, StringView new_path);
+ErrorOr<void> unlink(StringView path);
 ErrorOr<void> utime(StringView path, Optional<struct utimbuf>);
 ErrorOr<struct utsname> uname();
 ErrorOr<Array<int, 2>> pipe2(int flags);