diff --git a/common/utils/guestfs-utils.h b/common/utils/guestfs-utils.h
index 90e7c3dd9..b6508c669 100644
--- a/common/utils/guestfs-utils.h
+++ b/common/utils/guestfs-utils.h
@@ -70,6 +70,7 @@ extern int guestfs_int_is_fifo (int64_t mode);
 extern int guestfs_int_is_lnk (int64_t mode);
 extern int guestfs_int_is_sock (int64_t mode);
 extern char *guestfs_int_full_path (const char *dir, const char *name);
+extern void guestfs_int_hexdump (const void *data, size_t len, FILE *fp);
 
 /* Not all language bindings know how to deal with Pointer arguments.
  * Those that don't will use this macro which complains noisily and
diff --git a/common/utils/utils.c b/common/utils/utils.c
index a4c2d1e49..2af537bb1 100644
--- a/common/utils/utils.c
+++ b/common/utils/utils.c
@@ -733,3 +733,29 @@ guestfs_int_full_path (const char *dir, const char *name)
 
   return path;
 }
+
+/**
+ * Hexdump a block of memory to C<FILE *>, used for debugging.
+ */
+void
+guestfs_int_hexdump (const void *data, size_t len, FILE *fp)
+{
+  size_t i, j;
+
+  for (i = 0; i < len; i += 16) {
+    fprintf (fp, "%04zx: ", i);
+    for (j = i; j < MIN (i+16, len); ++j)
+      fprintf (fp, "%02x ", ((const unsigned char *)data)[j]);
+    for (; j < i+16; ++j)
+      fprintf (fp, "   ");
+    fprintf (fp, "|");
+    for (j = i; j < MIN (i+16, len); ++j)
+      if (c_isprint (((const char *)data)[j]))
+	fprintf (fp, "%c", ((const char *)data)[j]);
+      else
+	fprintf (fp, ".");
+    for (; j < i+16; ++j)
+      fprintf (fp, " ");
+    fprintf (fp, "|\n");
+  }
+}
diff --git a/daemon/proto.c b/daemon/proto.c
index 4f1249aa6..20cf99e9e 100644
--- a/daemon/proto.c
+++ b/daemon/proto.c
@@ -115,26 +115,8 @@ main_loop (int _sock)
       exit (EXIT_FAILURE);
 
 #ifdef ENABLE_PACKET_DUMP
-    if (verbose) {
-      size_t i, j;
-
-      for (i = 0; i < len; i += 16) {
-        printf ("%04zx: ", i);
-        for (j = i; j < MIN (i+16, len); ++j)
-          printf ("%02x ", (unsigned char) buf[j]);
-        for (; j < i+16; ++j)
-          printf ("   ");
-        printf ("|");
-        for (j = i; j < MIN (i+16, len); ++j)
-          if (c_isprint (buf[j]))
-            printf ("%c", buf[j]);
-          else
-            printf (".");
-        for (; j < i+16; ++j)
-          printf (" ");
-        printf ("|\n");
-      }
-    }
+    if (verbose)
+      guestfs_int_hexdump (buf, len, stdout);
 #endif
 
     gettimeofday (&start_t, NULL);
diff --git a/lib/proto.c b/lib/proto.c
index fba4831a6..2b39908f3 100644
--- a/lib/proto.c
+++ b/lib/proto.c
@@ -607,26 +607,8 @@ recv_from_daemon (guestfs_h *g, uint32_t *size_rtn, void **buf_rtn)
    * it if we're debugging.
    */
 #ifdef ENABLE_PACKET_DUMP
-  if (g->verbose) {
-    ssize_t i, j;
-
-    for (i = 0; i < n; i += 16) {
-      printf ("%04zx: ", i);
-      for (j = i; j < MIN (i+16, n); ++j)
-        printf ("%02x ", (*(unsigned char **)buf_rtn)[j]);
-      for (; j < i+16; ++j)
-        printf ("   ");
-      printf ("|");
-      for (j = i; j < MIN (i+16, n); ++j)
-        if (c_isprint ((*(char **)buf_rtn)[j]))
-          printf ("%c", (*(char **)buf_rtn)[j]);
-        else
-          printf (".");
-      for (; j < i+16; ++j)
-        printf (" ");
-      printf ("|\n");
-    }
-  }
+  if (g->verbose)
+    guestfs_int_hexdump (buf_rtn, n, stdout);
 #endif
 
   return 0;