Guarantees of gpg_strerror_r may not hold

[NIIBE Yutaka]

Hello,

John Scott via Gnupg-devel <gnupg-devel at gnupg.org> wrote:
> That means that if the caller didn't initialize their buffer, there is
> a risk of their buffer starting with uninitialized memory, something
> the GPGME docs say won't happen.

Thank you for your suggestion.

To be consistent to other parts of the code, something like this is more
appropriate, I suppose.

==========================
diff --git a/src/strerror.c b/src/strerror.c
index fb1bebf..51e57d8 100644
--- a/src/strerror.c
+++ b/src/strerror.c
@@ -96,7 +96,21 @@ system_strerror_r (int no, char *buf, size_t buflen)
 static int
 system_strerror_r (int no, char *buf, size_t buflen)
 {
-  return strerror_r (no, buf, buflen);
+  int saved_errno;
+  int r = strerror_r (no, buf, buflen);
+
+  if (r)
+    {
+      if (r < 0)
+        saved_errno = errno;
+      else
+        saved_errno = r;
+
+      snprintf (buf, buflen, "strerror_r failed: %i\n", r);
+      return saved_errno;
+    }
+
+  return 0;
 }
 
 #endif	/* STRERROR_R_CHAR_P */
--