3 files changed, 87 insertions, 8 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 36a607c..45be944 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -141,18 +141,14 @@ int dso__read_binary_type_filename(const struct dso *dso,
 	return ret;
 }
 
-static int decompress_dummy(const char *input __maybe_unused,
-			    int output __maybe_unused)
-{
-	return -1;
-}
-
 static const struct {
 	const char *fmt;
 	int (*decompress)(const char *input, int output);
 } compressions[] = {
-	{ "gz", decompress_dummy },
-	{ NULL, },
+#ifdef HAVE_ZLIB_SUPPORT
+	{ "gz", gzip_decompress_to_file },
+#endif
+	{ NULL, NULL },
 };
 
 bool is_supported_compression(const char *ext)
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 80bfdaa..7dc44cfe 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -351,4 +351,9 @@ void mem_bswap_32(void *src, int byte_size);
 
 const char *get_filename_for_perf_kvm(void);
 bool find_process(const char *name);
+
+#ifdef HAVE_ZLIB_SUPPORT
+int gzip_decompress_to_file(const char *input, int output_fd);
+#endif
+
 #endif /* GIT_COMPAT_UTIL_H */
diff --git a/tools/perf/util/zlib.c b/tools/perf/util/zlib.c
new file mode 100644
index 0000000..495a449
--- /dev/null
+++ b/tools/perf/util/zlib.c
@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <zlib.h>
+
+#include "util/util.h"
+#include "util/debug.h"
+
+
+#define CHUNK_SIZE  16384
+
+int gzip_decompress_to_file(const char *input, int output_fd)
+{
+	int ret = Z_STREAM_ERROR;
+	int input_fd;
+	void *ptr;
+	int len;
+	struct stat stbuf;
+	unsigned char buf[CHUNK_SIZE];
+	z_stream zs = {
+		.zalloc		= Z_NULL,
+		.zfree		= Z_NULL,
+		.opaque		= Z_NULL,
+		.avail_in	= 0,
+		.next_in	= Z_NULL,
+	};
+
+	input_fd = open(input, O_RDONLY);
+	if (input_fd < 0)
+		return -1;
+
+	if (fstat(input_fd, &stbuf) < 0)
+		goto out_close;
+
+	ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
+	if (ptr == MAP_FAILED)
+		goto out_close;
+
+	if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
+		goto out_unmap;
+
+	zs.next_in = ptr;
+	zs.avail_in = stbuf.st_size;
+
+	do {
+		zs.next_out = buf;
+		zs.avail_out = CHUNK_SIZE;
+
+		ret = inflate(&zs, Z_NO_FLUSH);
+		switch (ret) {
+		case Z_NEED_DICT:
+			ret = Z_DATA_ERROR;
+			/* fall through */
+		case Z_DATA_ERROR:
+		case Z_MEM_ERROR:
+			goto out;
+		default:
+			break;
+		}
+
+		len = CHUNK_SIZE - zs.avail_out;
+		if (writen(output_fd, buf, len) != len) {
+			ret = Z_DATA_ERROR;
+			goto out;
+		}
+
+	} while (ret != Z_STREAM_END);
+
+out:
+	inflateEnd(&zs);
+out_unmap:
+	munmap(ptr, stbuf.st_size);
+out_close:
+	close(input_fd);
+
+	return ret == Z_STREAM_END ? 0 : -1;
+}