We previously attempted to use the ESCAPE clause to set the escape delimiter to

a backslash.  Unfortunately, this does not universally work on all databases,
since on databases which natively use the backslash as a delimiter, the
backslash itself needs to be delimited, but on other databases that have no
delimiter, backslashing the backslash causes an error.

So the only solution that I can come up with is to create an option in res_odbc
that explicitly specifies whether or not backslash is a native delimiter.  If
it is, we use it natively; if not, we use the ESCAPE clause to make it one.

Reported by: elguero
Patch by: tilghman
(Closes issue #11364)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@89559 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/res_odbc.conf.sample

@@ -35,6 +35,9 @@ limit => 5
 username => oscar
 password => thegrouch
 pre-connect => yes
+; Many databases have a default of '\' to escape special characters.  MS SQL
+; Server does not.
+backslash_is_escape => no
 
 
 

include/asterisk/res_odbc.h

@@ -85,6 +85,12 @@ void ast_odbc_release_obj(struct odbc_obj *obj);
  */
 int ast_odbc_sanity_check(struct odbc_obj *obj);
 
+/*! \brief Checks if the database natively supports backslash as an escape character.
+ * \param obj The ODBC object
+ * \return Returns 1 if an ESCAPE clause is needed to support '\', 0 otherwise
+ */
+int ast_odbc_backslash_is_escape(struct odbc_obj *obj);
+
 /*! \brief Prepares, executes, and returns the resulting statement handle.
  * \param obj The ODBC object
  * \param prepare_cb A function callback, which, when called, should return a statement handle prepared, with any necessary parameters or result columns bound.

res/res_config_odbc.c

@@ -136,11 +136,12 @@ static struct ast_variable *realtime_odbc(const char *database, const char *tabl
 		return NULL;
 	newval = va_arg(aq, const char *);
 	op = !strchr(newparam, ' ') ? " =" : "";
-	snprintf(sql, sizeof(sql), "SELECT * FROM %s WHERE %s%s ?", table, newparam, op);
+	snprintf(sql, sizeof(sql), "SELECT * FROM %s WHERE %s%s ?%s", table, newparam, op,
+		strcasestr(newparam, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\'" : "");
 	while((newparam = va_arg(aq, const char *))) {
 		op = !strchr(newparam, ' ') ? " =" : "";
 		snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), " AND %s%s ?%s", newparam, op,
-			strcasestr(newparam, "LIKE") ? " ESCAPE '\\'" : "");
+			strcasestr(newparam, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\'" : "");
 		newval = va_arg(aq, const char *);
 	}
 	va_end(aq);
@@ -267,11 +268,11 @@ static struct ast_config *realtime_multi_odbc(const char *database, const char *
 	newval = va_arg(aq, const char *);
 	op = !strchr(newparam, ' ') ? " =" : "";
 	snprintf(sql, sizeof(sql), "SELECT * FROM %s WHERE %s%s ?%s", table, newparam, op,
-		strcasestr(newparam, "LIKE") ? " ESCAPE '\\'" : "");
+		strcasestr(newparam, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\'" : "");
 	while((newparam = va_arg(aq, const char *))) {
 		op = !strchr(newparam, ' ') ? " =" : "";
 		snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), " AND %s%s ?%s", newparam, op,
-			strcasestr(newparam, "LIKE") ? " ESCAPE '\\'" : "");
+			strcasestr(newparam, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\'" : "");
 		newval = va_arg(aq, const char *);
 	}
 	if (initfield)

res/res_odbc.c

@@ -66,6 +66,7 @@ struct odbc_class
 	unsigned int limit:10;          /* Gives a limit of 1023 maximum */
 	unsigned int count:10;          /* Running count of pooled connections */
 	unsigned int delme:1;			/* Purge the class */
+	unsigned int backslash_is_escape:1;	/* On this database, the backslash is a native escape sequence */
 	AST_LIST_HEAD(, odbc_obj) odbc_obj;
 };
 
@@ -212,7 +213,7 @@ static int load_odbc_config(void)
 	struct ast_config *config;
 	struct ast_variable *v;
 	char *cat, *dsn, *username, *password;
-	int enabled, pooling, limit;
+	int enabled, pooling, limit, bse;
 	int connect = 0, res = 0;
 
 	struct odbc_class *new;
@@ -235,6 +236,7 @@ static int load_odbc_config(void)
 			connect = 0;
 			pooling = 0;
 			limit = 0;
+			bse = 1;
 			for (v = ast_variable_browse(config, cat); v; v = v->next) {
 				if (!strcasecmp(v->name, "pooling")) {
 					if (ast_true(v->value))
@@ -259,6 +261,8 @@ static int load_odbc_config(void)
 					username = v->value;
 				} else if (!strcasecmp(v->name, "password")) {
 					password = v->value;
+				} else if (!strcasecmp(v->name, "backslash_is_escape")) {
+					bse = ast_true(v->value);
 				}
 			}
 
@@ -298,6 +302,8 @@ static int load_odbc_config(void)
 					}
 				}
 
+				new->backslash_is_escape = bse ? 1 : 0;
+
 				odbc_register_class(new, connect);
 				ast_log(LOG_NOTICE, "Registered ODBC class '%s' dsn->[%s]\n", cat, dsn);
 			}
@@ -379,6 +385,11 @@ void ast_odbc_release_obj(struct odbc_obj *obj)
 	obj->used = 0;
 }
 
+int ast_odbc_backslash_is_escape(struct odbc_obj *obj)
+{
+	return obj->parent->backslash_is_escape;
+}
+
 struct odbc_obj *ast_odbc_request_obj(const char *name, int check)
 {
 	struct odbc_obj *obj = NULL;
@@ -533,7 +544,7 @@ static int reload(void)
 	struct ast_config *config;
 	struct ast_variable *v;
 	char *cat, *dsn, *username, *password;
-	int enabled, pooling, limit;
+	int enabled, pooling, limit, bse;
 	int connect = 0, res = 0;
 
 	struct odbc_class *new, *class;
@@ -560,6 +571,7 @@ static int reload(void)
 				connect = 0;
 				pooling = 0;
 				limit = 0;
+				bse = 1;
 				for (v = ast_variable_browse(config, cat); v; v = v->next) {
 					if (!strcasecmp(v->name, "pooling")) {
 						pooling = 1;
@@ -583,6 +595,8 @@ static int reload(void)
 						username = v->value;
 					} else if (!strcasecmp(v->name, "password")) {
 						password = v->value;
+					} else if (!strcasecmp(v->name, "backslash_is_escape")) {
+						bse = ast_true(v->value);
 					}
 				}
 
@@ -637,6 +651,8 @@ static int reload(void)
 						}
 					}
 
+					new->backslash_is_escape = bse;
+
 					if (class) {
 						ast_log(LOG_NOTICE, "Refreshing ODBC class '%s' dsn->[%s]\n", cat, dsn);
 					} else {