[ulogd2 PATCH 17/26] output: DBI: fix string truncation warnings

[Jeremy Sowden <jeremy@azazel.net>]

Replace `strncpy` with `snprintf` and `memcpy`.

Remove intermediate buffer.

Ensure that `dst` is properly initialized if `dbi_conn_quote_string_copy`
returns an error.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
---
 output/dbi/ulogd_output_DBI.c | 46 +++++++++++++++--------------------
 1 file changed, 20 insertions(+), 26 deletions(-)

diff --git a/output/dbi/ulogd_output_DBI.c b/output/dbi/ulogd_output_DBI.c
index 461aed4bddb6..babaf58a9a56 100644
--- a/output/dbi/ulogd_output_DBI.c
+++ b/output/dbi/ulogd_output_DBI.c
@@ -91,15 +91,6 @@ static struct config_keyset dbi_kset = {
 #define dbtype_ce(x)	(x->ces[DB_CE_NUM+6])
 
 
-/* lower-cases s in place */
-static void str_tolower(char *s)
-{
-	while(*s) {
-		*s = tolower(*s);
-		s++;
-	}
-}
-
 /* find out which columns the table has */
 static int get_columns_dbi(struct ulogd_pluginstance *upi)
 {
@@ -139,25 +130,26 @@ static int get_columns_dbi(struct ulogd_pluginstance *upi)
 		return -ENOMEM;
 	}
 
-	for (ui=1; ui<=upi->input.num_keys; ui++) {
-		char buf[ULOGD_MAX_KEYLEN+1];
-		char *underscore;
-		const char* field_name = dbi_result_get_field_name(pi->result, ui);
+	for (ui = 1; ui <= upi->input.num_keys; ui++) {
+		const char *field_name = dbi_result_get_field_name(pi->result, ui);
+		char *cp;
 
 		if (!field_name)
 			break;
 
-		/* replace all underscores with dots */
-		strncpy(buf, field_name, ULOGD_MAX_KEYLEN);
-		while ((underscore = strchr(buf, '_')))
-			*underscore = '.';
+		snprintf(upi->input.keys[ui - 1].name,
+			 sizeof(upi->input.keys[ui - 1].name),
+			 "%s", field_name);
 
-		str_tolower(buf);
+		/* down-case and replace all underscores with dots */
+		for (cp = upi->input.keys[ui - 1].name; *cp; cp++) {
+			if (*cp == '_')
+				*cp = '.';
+			else
+				*cp = tolower(*cp);
+		}
 
-		DEBUGP("field '%s' found: ", buf);
-
-		/* add it to list of input keys */
-		strncpy(upi->input.keys[ui-1].name, buf, ULOGD_MAX_KEYLEN);
+		DEBUGP("field '%s' found: ", upi->input.keys[ui - 1].name);
 	}
 
 	/* ID is a sequence */
@@ -245,18 +237,20 @@ static int escape_string_dbi(struct ulogd_pluginstance *upi,
 	}
 
 	ret = dbi_conn_quote_string_copy(pi->dbh, src, &newstr);
-	if (ret <= 2)
+	if (ret == 0) {
+		*dst = '\0';
 		return 0;
+	}
 
 	/* dbi_conn_quote_string_copy returns a quoted string,
 	 * but __interp_db already quotes the string
 	 * So we return a string without the quotes
 	 */
-	strncpy(dst,newstr+1,ret-2);
-	dst[ret-2] = '\0';
+	memcpy(dst, newstr + 1, ret - 2);
+	dst[ret - 2] = '\0';
 	free(newstr);
 
-	return (ret-2);
+	return ret - 2;
 }
 
 static int execute_dbi(struct ulogd_pluginstance *upi,
-- 
2.33.0