1 files changed, 224 insertions, 0 deletions
diff --git a/nixos/modules/config/shells-environment.nix b/nixos/modules/config/shells-environment.nix
new file mode 100644
index 00000000000..ae3f618e273
--- /dev/null
+++ b/nixos/modules/config/shells-environment.nix
@@ -0,0 +1,224 @@
+# This module defines a global environment configuration and
+# a common configuration for all shells.
+
+{ config, lib, utils, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.environment;
+
+  exportedEnvVars =
+    let
+      absoluteVariables =
+        mapAttrs (n: toList) cfg.variables;
+
+      suffixedVariables =
+        flip mapAttrs cfg.profileRelativeEnvVars (envVar: listSuffixes:
+          concatMap (profile: map (suffix: "${profile}${suffix}") listSuffixes) cfg.profiles
+        );
+
+      allVariables =
+        zipAttrsWith (n: concatLists) [ absoluteVariables suffixedVariables ];
+
+      exportVariables =
+        mapAttrsToList (n: v: ''export ${n}="${concatStringsSep ":" v}"'') allVariables;
+    in
+      concatStringsSep "\n" exportVariables;
+in
+
+{
+
+  options = {
+
+    environment.variables = mkOption {
+      default = {};
+      example = { EDITOR = "nvim"; VISUAL = "nvim"; };
+      description = ''
+        A set of environment variables used in the global environment.
+        These variables will be set on shell initialisation (e.g. in /etc/profile).
+        The value of each variable can be either a string or a list of
+        strings.  The latter is concatenated, interspersed with colon
+        characters.
+      '';
+      type = with types; attrsOf (either str (listOf str));
+      apply = mapAttrs (n: v: if isList v then concatStringsSep ":" v else v);
+    };
+
+    environment.profiles = mkOption {
+      default = [];
+      description = ''
+        A list of profiles used to setup the global environment.
+      '';
+      type = types.listOf types.str;
+    };
+
+    environment.profileRelativeEnvVars = mkOption {
+      type = types.attrsOf (types.listOf types.str);
+      example = { PATH = [ "/bin" ]; MANPATH = [ "/man" "/share/man" ]; };
+      description = ''
+        Attribute set of environment variable.  Each attribute maps to a list
+        of relative paths.  Each relative path is appended to the each profile
+        of <option>environment.profiles</option> to form the content of the
+        corresponding environment variable.
+      '';
+    };
+
+    # !!! isn't there a better way?
+    environment.extraInit = mkOption {
+      default = "";
+      description = ''
+        Shell script code called during global environment initialisation
+        after all variables and profileVariables have been set.
+        This code is assumed to be shell-independent, which means you should
+        stick to pure sh without sh word split.
+      '';
+      type = types.lines;
+    };
+
+    environment.shellInit = mkOption {
+      default = "";
+      description = ''
+        Shell script code called during shell initialisation.
+        This code is assumed to be shell-independent, which means you should
+        stick to pure sh without sh word split.
+      '';
+      type = types.lines;
+    };
+
+    environment.loginShellInit = mkOption {
+      default = "";
+      description = ''
+        Shell script code called during login shell initialisation.
+        This code is assumed to be shell-independent, which means you should
+        stick to pure sh without sh word split.
+      '';
+      type = types.lines;
+    };
+
+    environment.interactiveShellInit = mkOption {
+      default = "";
+      description = ''
+        Shell script code called during interactive shell initialisation.
+        This code is assumed to be shell-independent, which means you should
+        stick to pure sh without sh word split.
+      '';
+      type = types.lines;
+    };
+
+    environment.shellAliases = mkOption {
+      example = { l = null; ll = "ls -l"; };
+      description = ''
+        An attribute set that maps aliases (the top level attribute names in
+        this option) to command strings or directly to build outputs. The
+        aliases are added to all users' shells.
+        Aliases mapped to <code>null</code> are ignored.
+      '';
+      type = with types; attrsOf (nullOr (either str path));
+    };
+
+    environment.homeBinInPath = mkOption {
+      description = ''
+        Include ~/bin/ in $PATH.
+      '';
+      default = false;
+      type = types.bool;
+    };
+
+    environment.localBinInPath = mkOption {
+      description = ''
+        Add ~/.local/bin/ to $PATH
+      '';
+      default = false;
+      type = types.bool;
+    };
+
+    environment.binsh = mkOption {
+      default = "${config.system.build.binsh}/bin/sh";
+      defaultText = literalExpression ''"''${config.system.build.binsh}/bin/sh"'';
+      example = literalExpression ''"''${pkgs.dash}/bin/dash"'';
+      type = types.path;
+      visible = false;
+      description = ''
+        The shell executable that is linked system-wide to
+        <literal>/bin/sh</literal>. Please note that NixOS assumes all
+        over the place that shell to be Bash, so override the default
+        setting only if you know exactly what you're doing.
+      '';
+    };
+
+    environment.shells = mkOption {
+      default = [];
+      example = literalExpression "[ pkgs.bashInteractive pkgs.zsh ]";
+      description = ''
+        A list of permissible login shells for user accounts.
+        No need to mention <literal>/bin/sh</literal>
+        here, it is placed into this list implicitly.
+      '';
+      type = types.listOf (types.either types.shellPackage types.path);
+    };
+
+  };
+
+  config = {
+
+    system.build.binsh = pkgs.bashInteractive;
+
+    # Set session variables in the shell as well. This is usually
+    # unnecessary, but it allows changes to session variables to take
+    # effect without restarting the session (e.g. by opening a new
+    # terminal instead of logging out of X11).
+    environment.variables = config.environment.sessionVariables;
+
+    environment.profileRelativeEnvVars = config.environment.profileRelativeSessionVariables;
+
+    environment.shellAliases = mapAttrs (name: mkDefault) {
+      ls = "ls --color=tty";
+      ll = "ls -l";
+      l  = "ls -alh";
+    };
+
+    environment.etc.shells.text =
+      ''
+        ${concatStringsSep "\n" (map utils.toShellPath cfg.shells)}
+        /bin/sh
+      '';
+
+    # For resetting environment with `. /etc/set-environment` when needed
+    # and discoverability (see motivation of #30418).
+    environment.etc.set-environment.source = config.system.build.setEnvironment;
+
+    system.build.setEnvironment = pkgs.writeText "set-environment"
+      ''
+        # DO NOT EDIT -- this file has been generated automatically.
+
+        # Prevent this file from being sourced by child shells.
+        export __NIXOS_SET_ENVIRONMENT_DONE=1
+
+        ${exportedEnvVars}
+
+        ${cfg.extraInit}
+
+        ${optionalString cfg.homeBinInPath ''
+          # ~/bin if it exists overrides other bin directories.
+          export PATH="$HOME/bin:$PATH"
+        ''}
+
+        ${optionalString cfg.localBinInPath ''
+          export PATH="$HOME/.local/bin:$PATH"
+        ''}
+      '';
+
+    system.activationScripts.binsh = stringAfter [ "stdio" ]
+      ''
+        # Create the required /bin/sh symlink; otherwise lots of things
+        # (notably the system() function) won't work.
+        mkdir -m 0755 -p /bin
+        ln -sfn "${cfg.binsh}" /bin/.sh.tmp
+        mv /bin/.sh.tmp /bin/sh # atomically replace /bin/sh
+      '';
+
+  };
+
+}