Line data Source code
1 : use std::collections::HashMap;
2 : use std::fmt;
3 :
4 : ///
5 : /// Module for parsing postgresql.conf file.
6 : ///
7 : /// NOTE: This doesn't implement the full, correct postgresql.conf syntax. Just
8 : /// enough to extract a few settings we need in Neon, assuming you don't do
9 : /// funny stuff like include-directives or funny escaping.
10 : use once_cell::sync::Lazy;
11 : use regex::Regex;
12 :
13 : /// In-memory representation of a postgresql.conf file
14 : #[derive(Default, Debug)]
15 : pub struct PostgresConf {
16 : lines: Vec<String>,
17 : hash: HashMap<String, String>,
18 : }
19 :
20 : impl PostgresConf {
21 0 : pub fn new() -> PostgresConf {
22 0 : PostgresConf::default()
23 0 : }
24 :
25 : /// Return the current value of 'option'
26 0 : pub fn get(&self, option: &str) -> Option<&str> {
27 0 : self.hash.get(option).map(|x| x.as_ref())
28 0 : }
29 :
30 : ///
31 : /// Note: if you call this multiple times for the same option, the config
32 : /// file will a line for each call. It would be nice to have a function
33 : /// to change an existing line, but that's a TODO.
34 : ///
35 0 : pub fn append(&mut self, option: &str, value: &str) {
36 0 : self.lines
37 0 : .push(format!("{}={}\n", option, escape_str(value)));
38 0 : self.hash.insert(option.to_string(), value.to_string());
39 0 : }
40 :
41 : /// Append an arbitrary non-setting line to the config file
42 0 : pub fn append_line(&mut self, line: &str) {
43 0 : self.lines.push(line.to_string());
44 0 : }
45 : }
46 :
47 : impl fmt::Display for PostgresConf {
48 : /// Return the whole configuration file as a string
49 0 : fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
50 0 : for line in self.lines.iter() {
51 0 : f.write_str(line)?;
52 : }
53 0 : Ok(())
54 0 : }
55 : }
56 :
57 : /// Escape a value for putting in postgresql.conf.
58 14 : fn escape_str(s: &str) -> String {
59 : // If the string doesn't contain anything that needs quoting or escaping, return it
60 : // as it is.
61 : //
62 : // The first part of the regex, before the '|', matches the INTEGER rule in the
63 : // PostgreSQL flex grammar (guc-file.l). It matches plain integers like "123" and
64 : // "-123", and also accepts units like "10MB". The second part of the regex matches
65 : // the UNQUOTED_STRING rule, and accepts strings that contain a single word, beginning
66 : // with a letter. That covers words like "off" or "posix". Everything else is quoted.
67 : //
68 : // This regex is a bit more conservative than the rules in guc-file.l, so we quote some
69 : // strings that PostgreSQL would accept without quoting, but that's OK.
70 :
71 : static UNQUOTED_RE: Lazy<Regex> =
72 1 : Lazy::new(|| Regex::new(r"(^[-+]?[0-9]+[a-zA-Z]*$)|(^[a-zA-Z][a-zA-Z0-9]*$)").unwrap());
73 :
74 14 : if UNQUOTED_RE.is_match(s) {
75 8 : s.to_string()
76 : } else {
77 : // Otherwise escape and quote it
78 6 : let s = s
79 6 : .replace('\\', "\\\\")
80 6 : .replace('\n', "\\n")
81 6 : .replace('\'', "''");
82 6 :
83 6 : "\'".to_owned() + &s + "\'"
84 : }
85 14 : }
86 :
87 : #[test]
88 1 : fn test_postgresql_conf_escapes() -> anyhow::Result<()> {
89 1 : assert_eq!(escape_str("foo bar"), "'foo bar'");
90 : // these don't need to be quoted
91 1 : assert_eq!(escape_str("foo"), "foo");
92 1 : assert_eq!(escape_str("123"), "123");
93 1 : assert_eq!(escape_str("+123"), "+123");
94 1 : assert_eq!(escape_str("-10"), "-10");
95 1 : assert_eq!(escape_str("1foo"), "1foo");
96 1 : assert_eq!(escape_str("foo1"), "foo1");
97 1 : assert_eq!(escape_str("10MB"), "10MB");
98 1 : assert_eq!(escape_str("-10kB"), "-10kB");
99 :
100 : // these need quoting and/or escaping
101 1 : assert_eq!(escape_str("foo bar"), "'foo bar'");
102 1 : assert_eq!(escape_str("fo'o"), "'fo''o'");
103 1 : assert_eq!(escape_str("fo\no"), "'fo\\no'");
104 1 : assert_eq!(escape_str("fo\\o"), "'fo\\\\o'");
105 1 : assert_eq!(escape_str("10 cats"), "'10 cats'");
106 :
107 1 : Ok(())
108 1 : }
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