pstore: Add decompression support to pstore
Based on the flag 'compressed' set or not, pstore will decompress the
data returning a plain text file. If decompression fails for a particular
record it will have the compressed data in the file which can be
decompressed with 'openssl' command line tool.
Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 6418eb7..76bc5c1 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -162,6 +162,36 @@
return ret;
}
+/* Derived from logfs_uncompress */
+static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
+{
+ int err, ret;
+
+ ret = -EIO;
+ err = zlib_inflateInit(&stream);
+ if (err != Z_OK)
+ goto error;
+
+ stream.next_in = in;
+ stream.avail_in = inlen;
+ stream.total_in = 0;
+ stream.next_out = out;
+ stream.avail_out = outlen;
+ stream.total_out = 0;
+
+ err = zlib_inflate(&stream, Z_FINISH);
+ if (err != Z_STREAM_END)
+ goto error;
+
+ err = zlib_inflateEnd(&stream);
+ if (err != Z_OK)
+ goto error;
+
+ ret = stream.total_out;
+error:
+ return ret;
+}
+
static void allocate_buf_for_compression(void)
{
size_t size;
@@ -429,6 +459,7 @@
struct timespec time;
int failed = 0, rc;
bool compressed;
+ int unzipped_len = -1;
if (!psi)
return;
@@ -439,10 +470,28 @@
while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
psi)) > 0) {
+ if (compressed && (type == PSTORE_TYPE_DMESG)) {
+ if (big_oops_buf)
+ unzipped_len = pstore_decompress(buf,
+ big_oops_buf, size,
+ big_oops_buf_sz);
+
+ if (unzipped_len > 0) {
+ buf = big_oops_buf;
+ size = unzipped_len;
+ } else {
+ pr_err("pstore: decompression failed;"
+ "returned %d\n", unzipped_len);
+ }
+ }
rc = pstore_mkfile(type, psi->name, id, count, buf,
(size_t)size, time, psi);
- kfree(buf);
- buf = NULL;
+ if (unzipped_len < 0) {
+ /* Free buffer other than big oops */
+ kfree(buf);
+ buf = NULL;
+ } else
+ unzipped_len = -1;
if (rc && (rc != -EEXIST || !quiet))
failed++;
}
