Add extra logging during compression and decompression

This helps diagnose failures.

Part of #22502.

1 files changed, 12 insertions, 1 deletions

diff --git a/src/common/compress.c b/src/common/compress.c
index ee9de6a768..e65894d9d2 100644
--- a/src/common/compress.c
+++ b/src/common/compress.c
@@ -102,8 +102,13 @@ tor_compress_impl(int compress,
 
   stream = tor_compress_new(compress, method, compression_level);
 
-  if (stream == NULL)
+  if (stream == NULL) {
+    log_warn(LD_GENERAL, "NULL stream while %scompressing",
+             compress?"":"de");
+    log_debug(LD_GENERAL, "method: %d level: %d at len: %zd",
+              method, compression_level, in_len);
     return -1;
+  }
 
   size_t in_len_orig = in_len;
   size_t out_remaining, out_alloc;
@@ -137,6 +142,12 @@ tor_compress_impl(int compress,
         break;
       case TOR_COMPRESS_OK:
         if (compress || complete_only) {
+          log_fn(protocol_warn_level, LD_PROTOCOL,
+                 "Unexpected %s while %scompressing",
+                 complete_only?"end of input":"result",
+                 compress?"":"de");
+          log_debug(LD_GENERAL, "method: %d level: %d at len: %zd",
+                    method, compression_level, in_len);
           goto err;
         } else {
           if (in_len != 0) {