calculate-overlay/sys-apps/kmod/files/zstd-support.patch

diff --git a/Makefile.am b/Makefile.am
index 47505c1..155456f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -89,7 +89,7 @@ libkmod_libkmod_la_DEPENDENCIES = \
 	${top_srcdir}/libkmod/libkmod.sym
 libkmod_libkmod_la_LIBADD = \
 	shared/libshared.la \
-	${liblzma_LIBS} ${zlib_LIBS} ${openssl_LIBS}
+	${libzstd_LIBS} ${liblzma_LIBS} ${zlib_LIBS} ${openssl_LIBS}
 
 noinst_LTLIBRARIES += libkmod/libkmod-internal.la
 libkmod_libkmod_internal_la_SOURCES = $(libkmod_libkmod_la_SOURCES)
diff --git a/configure.ac b/configure.ac
index e885d79..a286159 100644
--- a/configure.ac
+++ b/configure.ac
@@ -83,6 +83,17 @@ AC_ARG_WITH([rootlibdir],
         [], [with_rootlibdir=$libdir])
 AC_SUBST([rootlibdir], [$with_rootlibdir])
 
+AC_ARG_WITH([zstd],
+	AS_HELP_STRING([--with-zstd], [handle Zstd-compressed modules @<:@default=disabled@:>@]),
+	[], [with_zstd=no])
+AS_IF([test "x$with_zstd" != "xno"], [
+	PKG_CHECK_MODULES([libzstd], [libzstd >= 1.4.4])
+	AC_DEFINE([ENABLE_ZSTD], [1], [Enable Zstd for modules.])
+], [
+	AC_MSG_NOTICE([Zstd support not requested])
+])
+CC_FEATURE_APPEND([with_features], [with_zstd], [ZSTD])
+
 AC_ARG_WITH([xz],
 	AS_HELP_STRING([--with-xz], [handle Xz-compressed modules @<:@default=disabled@:>@]),
 	[], [with_xz=no])
@@ -307,7 +318,7 @@ AC_MSG_RESULT([
 	tools:			${enable_tools}
 	python bindings:	${enable_python}
 	logging:		${enable_logging}
-	compression:		xz=${with_xz}  zlib=${with_zlib}
+	compression:		zstd=${with_zstd}  xz=${with_xz}  zlib=${with_zlib}
 	debug:			${enable_debug}
 	coverage:		${enable_coverage}
 	doc:			${enable_gtk_doc}
diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index 5eeba6a..2575b01 100644
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -32,7 +32,9 @@
 #ifdef ENABLE_ZLIB
 #include <zlib.h>
 #endif
-
+#ifdef ENABLE_ZSTD
+#include <zstd.h>
+#endif
 #include <shared/util.h>
 
 #include "libkmod.h"
@@ -45,6 +47,9 @@ struct file_ops {
 };
 
 struct kmod_file {
+#ifdef ENABLE_ZSTD
+	bool zstd_used;
+#endif
 #ifdef ENABLE_XZ
 	bool xz_used;
 #endif
@@ -60,6 +65,79 @@ struct kmod_file {
 	struct kmod_elf *elf;
 };
 
+#ifdef ENABLE_ZSTD
+static int zstd_uncompress(ZSTD_DStream *strm, struct kmod_file *file) {
+	uint8_t in_buf[BUFSIZ], out_buf[BUFSIZ];
+	ZSTD_outBuffer output = { out_buf, sizeof(out_buf), 0 };
+	ZSTD_inBuffer input = { in_buf, 0, 0 };
+	void *p = NULL;
+	int ret = 0;
+	size_t total = 0;
+
+	while(true) {
+		size_t sz;
+		if (input.pos == input.size) {
+			ssize_t rdret = read(file->fd, in_buf, sizeof(in_buf));
+			if (rdret < 0) {
+				ret = -errno;
+				goto out;
+			}
+			input.size = rdret;
+			input.pos = 0;
+		}
+		if (input.size == 0) {
+			break;
+		}
+		sz = ZSTD_decompressStream(strm, &output, &input);
+		if (ZSTD_isError(sz)) {
+			ret = -1;
+			goto out;
+		}
+		if (output.pos == output.size || sz == 0) {
+			size_t write_size = output.pos;
+			char *tmp = realloc(p, total + write_size);
+			if (tmp == NULL) {
+				ret = -errno;
+				goto out;
+			}
+			memcpy(tmp + total, out_buf, write_size);
+			total += write_size;
+			p = tmp;
+			if (output.pos == output.size) {
+				output.pos = 0;
+			}
+		}
+	}
+	file->zstd_used = true;
+	file->memory = p;
+	file->size = total;
+	return 0;
+out:
+	free(p);
+	return ret;
+}
+
+static int load_zstd(struct kmod_file *file)
+{
+	ZSTD_DStream* strm = ZSTD_createDStream();
+	int ret;
+	ZSTD_initDStream(strm);
+
+	ret = zstd_uncompress(strm, file);
+	ZSTD_freeDStream(strm);
+	return ret;
+}
+
+static void unload_zstd(struct kmod_file *file)
+{
+	if (!file->zstd_used)
+		return;
+	free(file->memory);
+}
+
+static const char magic_zstd[] = {0x28, 0xb5, 0x2f, 0xfd};
+#endif
+
 #ifdef ENABLE_XZ
 static void xz_uncompress_belch(struct kmod_file *file, lzma_ret ret)
 {
@@ -238,6 +316,9 @@ static const struct comp_type {
 	const char *magic_bytes;
 	const struct file_ops ops;
 } comp_types[] = {
+#ifdef ENABLE_ZSTD
+	{sizeof(magic_zstd), magic_zstd, {load_zstd, unload_zstd}},
+#endif
 #ifdef ENABLE_XZ
 	{sizeof(magic_xz), magic_xz, {load_xz, unload_xz}},
 #endif
diff --git a/shared/util.c b/shared/util.c
index fd2028d..b487b5f 100644
--- a/shared/util.c
+++ b/shared/util.c
@@ -45,6 +45,9 @@ static const struct kmod_ext {
 #endif
 #ifdef ENABLE_XZ
 	{".ko.xz", sizeof(".ko.xz") - 1},
+#endif
+#ifdef ENABLE_ZSTD
+	{".ko.zst", sizeof(".ko.zst") - 1},
 #endif
 	{ }
 };
diff --git a/testsuite/test-util.c b/testsuite/test-util.c
index 5e25e58..621446b 100644
--- a/testsuite/test-util.c
+++ b/testsuite/test-util.c
@@ -156,6 +156,9 @@ static int test_path_ends_with_kmod_ext(const struct test *t)
 #endif
 #ifdef ENABLE_XZ
 		{ "/bla.ko.xz", true },
+#endif
+#ifdef ENABLE_ZSTD
+		{ "/bla.ko.zst", true },
 #endif
 		{ "/bla.ko.x", false },
 		{ "/bla.ko.", false },