add version check control parameter. leak fix (#90)

A new parameter 'VersionChecking' is added, to control how strict the
version check is performed:
- strict: the default; will only connect to a server with same version;
- major: major versions must match;
- none: only avail in debug builds; no version check.

The commit also fixes a memory leak: the body of the GET (containing the
server version) is now freed.

(cherry picked from commit fa258fd)

driver/connect.c

@@ -1063,9 +1063,9 @@ SQLRETURN config_dbc(esodbc_dbc_st *dbc, esodbc_dsn_attrs_st *attrs)
 	/*
 	 * set the REST body format: JSON/CBOR
 	 */
-	if (EQ_CASE_WSTR(&attrs->packing, &MK_WSTR("JSON"))) {
+	if (EQ_CASE_WSTR(&attrs->packing, &MK_WSTR(ESODBC_DSN_PACK_JSON))) {
 		dbc->pack_json = TRUE;
-	} else if (EQ_CASE_WSTR(&attrs->packing, &MK_WSTR("CBOR"))) {
+	} else if (EQ_CASE_WSTR(&attrs->packing, &MK_WSTR(ESODBC_DSN_PACK_CBOR))) {
 		dbc->pack_json = FALSE;
 	} else {
 		ERRH(dbc, "unknown packing encoding '" LWPDL "'.",
@@ -1075,6 +1075,28 @@ SQLRETURN config_dbc(esodbc_dbc_st *dbc, esodbc_dsn_attrs_st *attrs)
 	}
 	INFOH(dbc, "pack JSON: %s.", dbc->pack_json ? "true" : "false");
 
+	/*
+	 * Version checking mode
+	 */
+	if (EQ_CASE_WSTR(&attrs->version_checking,
+				&MK_WSTR(ESODBC_DSN_VC_STRICT))
+			|| EQ_CASE_WSTR(&attrs->version_checking,
+				&MK_WSTR(ESODBC_DSN_VC_MAJOR))
+#			ifndef NDEBUG
+			|| EQ_CASE_WSTR(&attrs->version_checking,
+				&MK_WSTR(ESODBC_DSN_VC_NONE))
+#			endif /* NDEBUG */
+			) {
+		dbc->srv_ver.checking = (unsigned char)attrs->version_checking.str[0];
+		DBGH(dbc, "version checking mode: %c.", dbc->srv_ver.checking);
+	} else {
+		ERRH(dbc, "unknown version checking mode '" LWPDL "'.",
+			LWSTR(&attrs->version_checking));
+		SET_HDIAG(dbc, SQL_STATE_HY000, "invalid version checking mode "
+				"setting", 0);
+		goto err;
+	}
+
 	return SQL_SUCCESS;
 err:
 	/* release allocated resources before the failure; not the diag, tho */
@@ -1146,6 +1168,11 @@ void cleanup_dbc(esodbc_dbc_st *dbc)
 	} else {
 		assert(dbc->no_types == 0);
 	}
+	if (dbc->srv_ver.string.cnt) { /* .str might be compromized by the union */
+		free(dbc->srv_ver.string.str);
+		dbc->srv_ver.string.str = NULL;
+		dbc->srv_ver.string.cnt = 0;
+	}
 
 	assert(dbc->abuff == NULL);
 	cleanup_curl(dbc);
@@ -1168,9 +1195,6 @@ static SQLRETURN check_server_version(esodbc_dbc_st *dbc)
 	const wchar_t *version_key[] = {L"number"};
 	wstr_st ver_no;
 	wstr_st own_ver = WSTR_INIT(STR(DRV_VERSION)); /*build-time define*/
-#	ifndef NDEBUG
-	SQLWCHAR *pos, *end;
-#	endif /* !NDEBUG */
 	static const wchar_t err_msg_fmt[] = L"Version mismatch between server ("
 		WPFWP_LDESC ") and driver (" WPFWP_LDESC "). Please use a driver whose"
 		" version matches that of your server.";
@@ -1223,34 +1247,51 @@ static SQLRETURN check_server_version(esodbc_dbc_st *dbc)
 
 #	ifndef NDEBUG
 	/* strip any qualifiers (=anything following a first `-`) in debug mode */
-	for (pos = ver_no.str, end = pos + ver_no.cnt; pos < end; pos ++) {
-		if (*pos == L'-') {
-			ver_no.cnt = pos - ver_no.str;
-			break;
-		}
-	}
-	for (pos = own_ver.str, end = pos + own_ver.cnt; pos < end; pos ++) {
-		if (*pos == L'-') {
-			own_ver.cnt = pos - own_ver.str;
-			break;
+	wtrim_at(&ver_no, L'-');
+	wtrim_at(&own_ver, L'-');
+#	endif /* !NDEBUG */
+
+	if (tolower(dbc->srv_ver.checking) == tolower(ESODBC_DSN_VC_MAJOR[0])) {
+		/* trim versions to the first dot, i.e. major version */
+		wtrim_at(&ver_no, L'.');
+		wtrim_at(&own_ver, L'.');
+	}
+
+	if (tolower(dbc->srv_ver.checking) != tolower(ESODBC_DSN_VC_NONE[0])) {
+		if (! EQ_WSTR(&ver_no, &own_ver)) {
+			ERRH(dbc, "version mismatch: server: " LWPDL ", "
+					"own: " LWPDL ".", LWSTR(&ver_no), LWSTR(&own_ver));
+			n = swprintf(wbuff, sizeof(wbuff)/sizeof(wbuff[0]),
+					err_msg_fmt, LWSTR(&ver_no), LWSTR(&own_ver));
+			ret = post_diagnostic(dbc, SQL_STATE_HY000, (n <= 0) ?
+					L"Version mismatch between server and driver" :
+					wbuff, 0);
+		} else {
+			INFOH(dbc, "server and driver versions aligned to: " LWPDL ".",
+					LWSTR(&own_ver));
+			ret = SQL_SUCCESS;
 		}
-	}
+#	ifndef NDEBUG
+	} else {
+		WARNH(dbc, "version checking disabled.");
 #	endif /* !NDEBUG */
+	}
 
-	if (! EQ_WSTR(&ver_no, &own_ver)) {
-		ERRH(dbc, "version mismatch: server: " LWPDL ", own: " LWPDL ".",
-				LWSTR(&ver_no), LWSTR(&own_ver));
-		n = swprintf(wbuff, sizeof(wbuff)/sizeof(wbuff[0]), err_msg_fmt,
-				LWSTR(&ver_no), LWSTR(&own_ver));
-		ret = post_diagnostic(dbc, SQL_STATE_HY000, (n <= 0) ?
-				L"Version mismatch between server and driver" :
-				wbuff, 0);
+	/* re-read the original version (before trimming) and dup it */
+	ver_no.str = (SQLWCHAR *)UJReadString(o_number, &ver_no.cnt);
+	/* version is returned to application, which requires a NTS => +1 for \0 */
+	if (! (dbc->srv_ver.string.str = malloc(ver_no.cnt * sizeof(SQLWCHAR) + /*\0*/1))) {
+		ERRNH(dbc, "OOM for %zd.", ver_no.cnt * sizeof(SQLWCHAR));
+		post_diagnostic(dbc, SQL_STATE_HY001, NULL, 0);
+		goto err;
 	} else {
-		INFOH(dbc, "server and driver versions aligned to: " LWPDL ".",
-				LWSTR(&own_ver));
-		ret = SQL_SUCCESS;
+		memcpy(dbc->srv_ver.string.str, ver_no.str,
+				ver_no.cnt * sizeof(SQLWCHAR));
+		dbc->srv_ver.string.cnt = ver_no.cnt;
+		dbc->srv_ver.string.str[ver_no.cnt] = 0;
 	}
 
+	free(resp.str);
 	assert(state);
 	UJFree(state);
 	return ret;
@@ -1259,6 +1300,7 @@ static SQLRETURN check_server_version(esodbc_dbc_st *dbc)
 	if (resp.cnt) {
 		ERRH(dbc, "failed to process server's answer: [%zu] `" LWPDL "`.",
 				resp.cnt, LCSTR(&resp));
+		free(resp.str);
 	}
 	if (state) {
 		UJFree(state);

driver/defs.h

@@ -164,7 +164,9 @@
 #define ESODBC_DEF_TRACE_ENABLED	"0"
 /* default tracing level */
 #define ESODBC_DEF_TRACE_LEVEL		"WARN"
-#define ESODBC_PWD_VAL_SUBST		"<original substituted>"
+#define ESODBC_PWD_VAL_SUBST		"<redacted>"
+/* default version checking mode: strict, major, none (dbg only) */
+#define ESODBC_DEF_VERSION_CHECKING	ESODBC_DSN_VC_STRICT
 
 /*
  *

driver/dsn.c

@@ -77,6 +77,7 @@ int assign_dsn_attr(esodbc_dsn_attrs_st *attrs,
 		{&MK_WSTR(ESODBC_DSN_PACKING), &attrs->packing},
 		{&MK_WSTR(ESODBC_DSN_MAX_FETCH_SIZE), &attrs->max_fetch_size},
 		{&MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB), &attrs->max_body_size},
+		{&MK_WSTR(ESODBC_DSN_VERSION_CHECKING), &attrs->version_checking},
 		{&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &attrs->trace_enabled},
 		{&MK_WSTR(ESODBC_DSN_TRACE_FILE), &attrs->trace_file},
 		{&MK_WSTR(ESODBC_DSN_TRACE_LEVEL), &attrs->trace_level},
@@ -404,6 +405,7 @@ long TEST_API write_00_list(esodbc_dsn_attrs_st *attrs,
 		{&MK_WSTR(ESODBC_DSN_PACKING), &attrs->packing},
 		{&MK_WSTR(ESODBC_DSN_MAX_FETCH_SIZE), &attrs->max_fetch_size},
 		{&MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB), &attrs->max_body_size},
+		{&MK_WSTR(ESODBC_DSN_VERSION_CHECKING), &attrs->version_checking},
 		{&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &attrs->trace_enabled},
 		{&MK_WSTR(ESODBC_DSN_TRACE_FILE), &attrs->trace_file},
 		{&MK_WSTR(ESODBC_DSN_TRACE_LEVEL), &attrs->trace_level},
@@ -673,6 +675,11 @@ BOOL write_system_dsn(esodbc_dsn_attrs_st *new_attrs,
 			&MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB), &new_attrs->max_body_size,
 			old_attrs ? &old_attrs->max_body_size : NULL
 		},
+		{
+			&MK_WSTR(ESODBC_DSN_VERSION_CHECKING),
+			&new_attrs->version_checking,
+			old_attrs ? &old_attrs->version_checking : NULL
+		},
 		{
 			&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &new_attrs->trace_enabled,
 			old_attrs ? &old_attrs->trace_enabled : NULL
@@ -757,6 +764,7 @@ long TEST_API write_connection_string(esodbc_dsn_attrs_st *attrs,
 		{&attrs->packing, &MK_WSTR(ESODBC_DSN_PACKING)},
 		{&attrs->max_fetch_size, &MK_WSTR(ESODBC_DSN_MAX_FETCH_SIZE)},
 		{&attrs->max_body_size, &MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB)},
+		{&attrs->version_checking, &MK_WSTR(ESODBC_DSN_VERSION_CHECKING)},
 		{&attrs->trace_enabled, &MK_WSTR(ESODBC_DSN_TRACE_ENABLED)},
 		{&attrs->trace_file, &MK_WSTR(ESODBC_DSN_TRACE_FILE)},
 		{&attrs->trace_level, &MK_WSTR(ESODBC_DSN_TRACE_LEVEL)},
@@ -835,6 +843,9 @@ void assign_dsn_defaults(esodbc_dsn_attrs_st *attrs)
 	res |= assign_dsn_attr(attrs, &MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB),
 			&MK_WSTR(ESODBC_DEF_MAX_BODY_SIZE_MB),
 			/*overwrite?*/FALSE);
+	res |= assign_dsn_attr(attrs, &MK_WSTR(ESODBC_DSN_VERSION_CHECKING),
+			&MK_WSTR(ESODBC_DEF_VERSION_CHECKING),
+			/*overwrite?*/FALSE);
 
 	/* default: no trace file */
 	res |= assign_dsn_attr(attrs,

driver/dsn.h

@@ -32,10 +32,19 @@
 #define ESODBC_DSN_PACKING			"Packing"
 #define ESODBC_DSN_MAX_FETCH_SIZE	"MaxFetchSize"
 #define ESODBC_DSN_MAX_BODY_SIZE_MB	"MaxBodySizeMB"
+#define ESODBC_DSN_VERSION_CHECKING	"VersionChecking"
 #define ESODBC_DSN_TRACE_ENABLED	"TraceEnabled"
 #define ESODBC_DSN_TRACE_FILE		"TraceFile"
 #define ESODBC_DSN_TRACE_LEVEL		"TraceLevel"
 
+/* Packing values */
+#define ESODBC_DSN_PACK_JSON		"JSON"
+#define ESODBC_DSN_PACK_CBOR		"CBOR"
+/* VersionChecking values */
+#define ESODBC_DSN_VC_STRICT		"strict"
+#define ESODBC_DSN_VC_MAJOR			"major"
+#define ESODBC_DSN_VC_NONE			"none"
+
 /* stucture to collect all attributes in a connection string */
 typedef struct {
 	wstr_st driver;
@@ -55,10 +64,11 @@ typedef struct {
 	wstr_st packing;
 	wstr_st max_fetch_size;
 	wstr_st max_body_size;
+	wstr_st version_checking;
 	wstr_st trace_enabled;
 	wstr_st trace_file;
 	wstr_st trace_level;
-#define ESODBC_DSN_ATTRS_COUNT	20
+#define ESODBC_DSN_ATTRS_COUNT	21
 	SQLWCHAR buff[ESODBC_DSN_ATTRS_COUNT * ESODBC_DSN_MAX_ATTR_LEN];
 } esodbc_dsn_attrs_st;
 

driver/handles.h

@@ -130,6 +130,10 @@ typedef struct struct_dbc {
 
 	wstr_st dsn; /* data source name SQLGetInfo(SQL_DATA_SOURCE_NAME) */
 	wstr_st server; /* ~ name; requested with SQLGetInfo(SQL_SERVER_NAME) */
+	union {
+		wstr_st string; /* version: SQLGetInfo(SQL_DBMS_VER)  */
+		unsigned char checking; /* first letter of DSN config option */
+	} srv_ver; /* server version */
 	cstr_st url; /* SQL URL (posts) */
 	cstr_st root_url; /* root URL (gets) */
 	enum {

driver/info.c

@@ -304,8 +304,9 @@ static SQLRETURN getinfo_dbms_product(
 					&MK_WSTR(ESODBC_ELASTICSEARCH_NAME), BufferLength,
 					StringLengthPtr);
 		case SQL_DBMS_VER:
-			DBGH(dbc, "requested: DBMS version (`%s`).", STR(DRV_VERSION));
-			return write_wstr(dbc, InfoValue, &MK_WSTR(STR(DRV_VERSION)),
+			DBGH(dbc, "requested: DBMS version (`" LWPDL "`).",
+					LWSTR(&dbc->srv_ver.string));
+			return write_wstr(dbc, InfoValue, &dbc->srv_ver.string,
 					BufferLength, StringLengthPtr);
 	}
 	*handled = FALSE;

driver/util.c

@@ -287,6 +287,18 @@ void trim_ws(cstr_st *cstr)
 	};
 }
 
+BOOL wtrim_at(wstr_st *wstr, SQLWCHAR wchar)
+{
+	SQLWCHAR *pos, *end;
+
+	for (pos = wstr->str, end = pos + wstr->cnt; pos < end; pos ++) {
+		if (*pos == wchar) {
+			wstr->cnt = pos - wstr->str;
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
 
 /*
  * Converts a wchar_t string to a C string for ASCII characters.
@@ -398,7 +410,8 @@ static inline size_t json_escaped_len(const char *json, size_t len)
 		switch(uchar) {
 			case '"':
 			case '\\':
-			case '/':
+			/* '/' needs no quoting as per ECMA spec, even if listed on
+			 * json.org; ES/SQL uses it unescaped in cursor values. */
 			case '\b':
 			case '\f':
 			case '\n':
@@ -449,7 +462,8 @@ size_t json_escape(const char *jin, size_t inlen, char *jout, size_t outlen)
 			} while (0);
 			case '"':
 			case '\\':
-			case '/':
+			/* '/' needs no quoting as per ECMA spec, even if listed on
+			 * json.org; ES/SQL uses it unescaped in cursor values. */
 				if (outlen <= pos + 1) {
 					i = inlen; // break the for loop
 					continue;

driver/util.h

@@ -153,7 +153,9 @@ void trim_ws(cstr_st *str);
 void wltrim_ws(wstr_st *wstr);
 void wrtrim_ws(wstr_st *wstr);
 #define wtrim_ws(_w) do { wltrim_ws(_w); wrtrim_ws(_w); } while (0)
-
+/* Trim the w-string at first encounter of the give w-char.
+ * Returns TRUE if character has been encounter / trimming occured. */
+BOOL wtrim_at(wstr_st *wstr, SQLWCHAR wchar);
 
 BOOL wstr2bool(wstr_st *val);
 /* Converts a [cw]str_st to a SQL(U)BIGINT.