--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/fitz/log.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,87 @@
+// Copyright (C) 2004-2021 Artifex Software, Inc.
+//
+// This file is part of MuPDF.
+//
+// MuPDF is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
+//
+// Alternative licensing terms are available from the licensor.
+// For commercial licensing, see <https://www.artifex.com/> or contact
+// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
+// CA 94129, USA, for further information.
+
+#include "mupdf/fitz.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+fz_output *fz_new_log_for_module(fz_context *ctx, const char *module)
+{
+	char text[256];
+	char *s = NULL;
+
+	if (module)
+	{
+		fz_snprintf(text, sizeof(text), "FZ_LOG_FILE_%s", module);
+		s = getenv(text);
+	}
+	if (s == NULL)
+		s = getenv("FZ_LOG_FILE");
+	if (s == NULL)
+		s = "fitz_log.txt";
+	return fz_new_output_with_path(ctx, s, 1);
+}
+
+void fz_log(fz_context *ctx, const char *fmt, ...)
+{
+	fz_output *out;
+	va_list args;
+	va_start(args, fmt);
+	fz_try(ctx)
+	{
+		out = fz_new_log_for_module(ctx, NULL);
+		fz_write_vprintf(ctx, out, fmt, args);
+		fz_close_output(ctx, out);
+	}
+	fz_always(ctx)
+	{
+		va_end(args);
+		fz_drop_output(ctx, out);
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+
+void fz_log_module(fz_context *ctx, const char *module, const char *fmt, ...)
+{
+	fz_output *out;
+	va_list args;
+	va_start(args, fmt);
+	fz_try(ctx)
+	{
+		out = fz_new_log_for_module(ctx, module);
+		if (module)
+			fz_write_printf(ctx, out, "%s\t", module);
+		fz_write_vprintf(ctx, out, fmt, args);
+		fz_close_output(ctx, out);
+	}
+	fz_always(ctx)
+	{
+		va_end(args);
+		fz_drop_output(ctx, out);
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}