Avoid interleaving stderr in dump_fingerprint

* src/fns.c (hexbuf_digest): New function, containing most of
the old make_digest_string.
(make_digest_string): Use it.
* src/pdumper.c (dump_fingerprint): Rewrite to use a single
fprintf call, to avoid interleaving on GNU/Linux.

1 files changed, 14 insertions, 5 deletions

diff --git a/src/fns.c b/src/fns.c
index 6a7c3477282..54dafe07ac8 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -5040,18 +5040,27 @@ returns nil, then (funcall TEST x1 x2) also returns nil.  */)
 #include "sha256.h"
 #include "sha512.h"
 
-static Lisp_Object
-make_digest_string (Lisp_Object digest, int digest_size)
+/* Store into HEXBUF an unterminated hexadecimal character string
+   representing DIGEST, which is binary data of size DIGEST_SIZE bytes.
+   HEXBUF might equal DIGEST.  */
+void
+hexbuf_digest (char *hexbuf, void const *digest, int digest_size)
 {
-  unsigned char *p = SDATA (digest);
+  unsigned char const *p = digest;
 
   for (int i = digest_size - 1; i >= 0; i--)
     {
       static char const hexdigit[16] = "0123456789abcdef";
       int p_i = p[i];
-      p[2 * i] = hexdigit[p_i >> 4];
-      p[2 * i + 1] = hexdigit[p_i & 0xf];
+      hexbuf[2 * i] = hexdigit[p_i >> 4];
+      hexbuf[2 * i + 1] = hexdigit[p_i & 0xf];
     }
+}
+
+static Lisp_Object
+make_digest_string (Lisp_Object digest, int digest_size)
+{
+  hexbuf_digest (SSDATA (digest), SDATA (digest), digest_size);
   return digest;
 }