Fix escaping in postgresql.conf that we generate at compute startup

If there are any config options that contain single quotes or backslashes,
they need to be escaped

compute_tools/src/pg_helpers.rs

@@ -47,12 +47,23 @@ pub struct GenericOption {
 /// declare a `trait` on it.
 pub type GenericOptions = Option<Vec<GenericOption>>;
 
+/// Escape a string for including it in a SQL literal
+fn escape_literal(s: &str) -> String {
+    s.replace('\'', "''").replace('\\', "\\\\")
+}
+
+/// Escape a string so that it can be used in postgresql.conf.
+/// Same as escape_literal, currently.
+fn escape_conf_value(s: &str) -> String {
+    s.replace('\'', "''").replace('\\', "\\\\")
+}
+
 impl GenericOption {
     /// Represent `GenericOption` as SQL statement parameter.
     pub fn to_pg_option(&self) -> String {
         if let Some(val) = &self.value {
             match self.vartype.as_ref() {
-                "string" => format!("{} '{}'", self.name, val),
+                "string" => format!("{} '{}'", self.name, escape_literal(val)),
                 _ => format!("{} {}", self.name, val),
             }
         } else {
@@ -73,7 +84,7 @@ impl GenericOption {
             };
 
             match self.vartype.as_ref() {
-                "string" => format!("{} = '{}'", name, val),
+                "string" => format!("{} = '{}'", name, escape_conf_value(val)),
                 _ => format!("{} = {}", name, val),
             }
         } else {

compute_tools/tests/cluster_spec.json

@@ -178,6 +178,11 @@
                 "name": "neon.pageserver_connstring",
                 "value": "host=127.0.0.1 port=6400",
                 "vartype": "string"
+            },
+            {
+                "name": "test.escaping",
+                "value": "here's a backslash \\ and a quote ' and a double-quote \" hooray",
+                "vartype": "string"
             }
         ]
     },

compute_tools/tests/pg_helpers_tests.rs

@@ -50,6 +50,7 @@ neon.timeline_id = '2414a61ffc94e428f14b5758fe308e13'
 shared_preload_libraries = 'neon'
 synchronous_standby_names = 'walproposer'
 neon.pageserver_connstring = 'host=127.0.0.1 port=6400'
+test.escaping = 'here''s a backslash \\ and a quote '' and a double-quote " hooray'
 "#
         );
     }