add OSSL_TRACE_STRING(), OSSL_TRACE_STRING_MAX, and OSSL_trace_string()

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/18704)

1 files changed, 25 insertions, 0 deletions

diff --git a/crypto/trace.c b/crypto/trace.c
index 3bf9ff62f7..8e5836de32 100644
--- a/crypto/trace.c
+++ b/crypto/trace.c
@@ -18,6 +18,7 @@
 #include "internal/nelem.h"
 #include "internal/refcount.h"
 #include "crypto/cryptlib.h"
+#include "crypto/ctype.h"
 
 #ifndef OPENSSL_NO_TRACE
 
@@ -530,3 +531,27 @@ void OSSL_trace_end(int category, BIO * channel)
     }
 #endif
 }
+
+int OSSL_trace_string(BIO *out, int text, int full,
+                      const unsigned char *data, size_t size)
+{
+    unsigned char buf[OSSL_TRACE_STRING_MAX + 1];
+    int len, i;
+
+    if (!full && size > OSSL_TRACE_STRING_MAX) {
+        BIO_printf(out, "[len %zu limited to %d]: ",
+                   size, OSSL_TRACE_STRING_MAX);
+        len = OSSL_TRACE_STRING_MAX;
+    } else {
+        len = (int)size;
+    }
+    if (!text) { /* mask control characters while preserving newlines */
+        for (i = 0; i < len; i++, data++)
+            buf[i] = (char)*data != '\n' && ossl_iscntrl((int)*data)
+                ? ' ' : *data;
+        if (len == 0 || data[-1] != '\n')
+            buf[len++] = '\n';
+        data = buf;
+    }
+    return BIO_printf(out, "%.*s", len, data);
+}