clippy_lints/src/non_octal_unix_permissions.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::source::{snippet_opt, snippet_with_applicability};
   3 use clippy_utils::ty::match_type;
   4 use clippy_utils::{match_def_path, paths};
   5 use if_chain::if_chain;
   6 use rustc_errors::Applicability;
   7 use rustc_hir::{Expr, ExprKind};
   8 use rustc_lint::{LateContext, LateLintPass};
   9 use rustc_session::{declare_lint_pass, declare_tool_lint};
  10
  11 declare_clippy_lint! {
  12     /// ### What it does
  13     /// Checks for non-octal values used to set Unix file permissions.
  14     ///
  15     /// ### Why is this bad?
  16     /// They will be converted into octal, creating potentially
  17     /// unintended file permissions.
  18     ///
  19     /// ### Example
  20     /// ```rust,ignore
  21     /// use std::fs::OpenOptions;
  22     /// use std::os::unix::fs::OpenOptionsExt;
  23     ///
  24     /// let mut options = OpenOptions::new();
  25     /// options.mode(644);
  26     /// ```
  27     /// Use instead:
  28     /// ```rust,ignore
  29     /// use std::fs::OpenOptions;
  30     /// use std::os::unix::fs::OpenOptionsExt;
  31     ///
  32     /// let mut options = OpenOptions::new();
  33     /// options.mode(0o644);
  34     /// ```
  35     pub NON_OCTAL_UNIX_PERMISSIONS,
  36     correctness,
  37     "use of non-octal value to set unix file permissions, which will be translated into octal"
  38 }
  39
  40 declare_lint_pass!(NonOctalUnixPermissions => [NON_OCTAL_UNIX_PERMISSIONS]);
  41
  42 impl LateLintPass<'_> for NonOctalUnixPermissions {
  43     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
  44         match &expr.kind {
  45             ExprKind::MethodCall(path, _, [func, param], _) => {
  46                 let obj_ty = cx.typeck_results().expr_ty(func).peel_refs();
  47
  48                 if_chain! {
  49                     if (path.ident.name == sym!(mode)
  50                         && (match_type(cx, obj_ty, &paths::OPEN_OPTIONS)
  51                             || match_type(cx, obj_ty, &paths::DIR_BUILDER)))
  52                         || (path.ident.name == sym!(set_mode) && match_type(cx, obj_ty, &paths::PERMISSIONS));
  53                     if let ExprKind::Lit(_) = param.kind;
  54
  55                     then {
  56                         let snip = match snippet_opt(cx, param.span) {
  57                             Some(s) => s,
  58                             _ => return,
  59                         };
  60
  61                         if !snip.starts_with("0o") {
  62                             show_error(cx, param);
  63                         }
  64                     }
  65                 }
  66             },
  67             ExprKind::Call(func, [param]) => {
  68                 if_chain! {
  69                     if let ExprKind::Path(ref path) = func.kind;
  70                     if let Some(def_id) = cx.qpath_res(path, func.hir_id).opt_def_id();
  71                     if match_def_path(cx, def_id, &paths::PERMISSIONS_FROM_MODE);
  72                     if let ExprKind::Lit(_) = param.kind;
  73
  74                     then {
  75                         let snip = match snippet_opt(cx, param.span) {
  76                             Some(s) => s,
  77                             _ => return,
  78                         };
  79
  80                         if !snip.starts_with("0o") {
  81                             show_error(cx, param);
  82                         }
  83                     }
  84                 }
  85             },
  86             _ => {},
  87         };
  88     }
  89 }
  90
  91 fn show_error(cx: &LateContext<'_>, param: &Expr<'_>) {
  92     let mut applicability = Applicability::MachineApplicable;
  93     span_lint_and_sugg(
  94         cx,
  95         NON_OCTAL_UNIX_PERMISSIONS,
  96         param.span,
  97         "using a non-octal value to set unix file permissions",
  98         "consider using an octal literal instead",
  99         format!(
 100             "0o{}",
 101             snippet_with_applicability(cx, param.span, "0o..", &mut applicability,),
 102         ),
 103         applicability,
 104     );
 105 }