[PATCH v4 4/6] fs/squashfs: add support for zlib decompression

[Joao Marcos Costa]

Add call to zlib's 'uncompress' function. Add function to display the
right error message depending on the decompression's return value.

Signed-off-by: Joao Marcos Costa <joaomarcos.costa at bootlin.com>
---
Changes in v4:
	- Add preprocessor directives to check if a given compression option
	is enabled, starting by ZLIB. As long as other options get supported,
	their respective directives will be added as well.
Changes in v3:
	- No changes since v2.
Changes in v2:
	- No changes since v1.
 fs/squashfs/sqfs_decompressor.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/fs/squashfs/sqfs_decompressor.c b/fs/squashfs/sqfs_decompressor.c
index a899a5704b..09ca6cf6d0 100644
--- a/fs/squashfs/sqfs_decompressor.c
+++ b/fs/squashfs/sqfs_decompressor.c
@@ -9,17 +9,47 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
+#if IS_ENABLED(CONFIG_ZLIB)
+#include <u-boot/zlib.h>
+#endif
 
 #include "sqfs_decompressor.h"
 #include "sqfs_filesystem.h"
 #include "sqfs_utils.h"
 
+#if IS_ENABLED(CONFIG_ZLIB)
+static void zlib_decompression_status(int ret)
+{
+	switch (ret) {
+	case Z_BUF_ERROR:
+		printf("Error: 'dest' buffer is not large enough.\n");
+		break;
+	case Z_DATA_ERROR:
+		printf("Error: corrupted compressed data.\n");
+		break;
+	case Z_MEM_ERROR:
+		printf("Error: insufficient memory.\n");
+		break;
+	}
+}
+#endif
+
 int sqfs_decompress(u16 comp_type, void *dest, unsigned long *dest_len,
 		    void *source, u32 lenp)
 {
 	int ret = 0;
 
 	switch (comp_type) {
+#if IS_ENABLED(CONFIG_ZLIB)
+	case SQFS_COMP_ZLIB:
+		ret = uncompress(dest, dest_len, source, lenp);
+		if (ret) {
+			zlib_decompression_status(ret);
+			return -EINVAL;
+		}
+
+		break;
+#endif
 	default:
 		printf("Error: unknown compression type.\n");
 		return -EINVAL;
-- 
2.17.1