nixpkgs/nixos/lib/utils.nix
talyz b549e7bbb5
genJqSecretsReplacementSnippet: Fix error handling
With the previous change that enabled error propagation through
`inherit_errexit`, the script would fail if `errexit` was set, but
`inherit_errexit` was not. This is due to `shopt -p` exiting with an
error if the option is disabled. To work around this, use the exit
code instead of the text value returned by `shopt -p`.

Fixes #160869.
2022-02-23 12:48:51 +01:00

182 lines
6.0 KiB
Nix

{ lib, config, pkgs }: with lib;
rec {
# Copy configuration files to avoid having the entire sources in the system closure
copyFile = filePath: pkgs.runCommand (builtins.unsafeDiscardStringContext (builtins.baseNameOf filePath)) {} ''
cp ${filePath} $out
'';
# Check whenever fileSystem is needed for boot. NOTE: Make sure
# pathsNeededForBoot is closed under the parent relationship, i.e. if /a/b/c
# is in the list, put /a and /a/b in as well.
pathsNeededForBoot = [ "/" "/nix" "/nix/store" "/var" "/var/log" "/var/lib" "/var/lib/nixos" "/etc" "/usr" ];
fsNeededForBoot = fs: fs.neededForBoot || elem fs.mountPoint pathsNeededForBoot;
# Check whenever `b` depends on `a` as a fileSystem
fsBefore = a: b:
let
# normalisePath adds a slash at the end of the path if it didn't already
# have one.
#
# The reason slashes are added at the end of each path is to prevent `b`
# from accidentally depending on `a` in cases like
# a = { mountPoint = "/aaa"; ... }
# b = { device = "/aaaa"; ... }
# Here a.mountPoint *is* a prefix of b.device even though a.mountPoint is
# *not* a parent of b.device. If we add a slash at the end of each string,
# though, this is not a problem: "/aaa/" is not a prefix of "/aaaa/".
normalisePath = path: "${path}${optionalString (!(hasSuffix "/" path)) "/"}";
normalise = mount: mount // { device = normalisePath (toString mount.device);
mountPoint = normalisePath mount.mountPoint;
depends = map normalisePath mount.depends;
};
a' = normalise a;
b' = normalise b;
in hasPrefix a'.mountPoint b'.device
|| hasPrefix a'.mountPoint b'.mountPoint
|| any (hasPrefix a'.mountPoint) b'.depends;
# Escape a path according to the systemd rules, e.g. /dev/xyzzy
# becomes dev-xyzzy. FIXME: slow.
escapeSystemdPath = s:
replaceChars ["/" "-" " "] ["-" "\\x2d" "\\x20"]
(removePrefix "/" s);
# Returns a system path for a given shell package
toShellPath = shell:
if types.shellPackage.check shell then
"/run/current-system/sw${shell.shellPath}"
else if types.package.check shell then
throw "${shell} is not a shell package"
else
shell;
/* Recurse into a list or an attrset, searching for attrs named like
the value of the "attr" parameter, and return an attrset where the
names are the corresponding jq path where the attrs were found and
the values are the values of the attrs.
Example:
recursiveGetAttrWithJqPrefix {
example = [
{
irrelevant = "not interesting";
}
{
ignored = "ignored attr";
relevant = {
secret = {
_secret = "/path/to/secret";
};
};
}
];
} "_secret" -> { ".example[1].relevant.secret" = "/path/to/secret"; }
*/
recursiveGetAttrWithJqPrefix = item: attr:
let
recurse = prefix: item:
if item ? ${attr} then
nameValuePair prefix item.${attr}
else if isAttrs item then
map (name: recurse (prefix + "." + name) item.${name}) (attrNames item)
else if isList item then
imap0 (index: item: recurse (prefix + "[${toString index}]") item) item
else
[];
in listToAttrs (flatten (recurse "" item));
/* Takes an attrset and a file path and generates a bash snippet that
outputs a JSON file at the file path with all instances of
{ _secret = "/path/to/secret" }
in the attrset replaced with the contents of the file
"/path/to/secret" in the output JSON.
When a configuration option accepts an attrset that is finally
converted to JSON, this makes it possible to let the user define
arbitrary secret values.
Example:
If the file "/path/to/secret" contains the string
"topsecretpassword1234",
genJqSecretsReplacementSnippet {
example = [
{
irrelevant = "not interesting";
}
{
ignored = "ignored attr";
relevant = {
secret = {
_secret = "/path/to/secret";
};
};
}
];
} "/path/to/output.json"
would generate a snippet that, when run, outputs the following
JSON file at "/path/to/output.json":
{
"example": [
{
"irrelevant": "not interesting"
},
{
"ignored": "ignored attr",
"relevant": {
"secret": "topsecretpassword1234"
}
}
]
}
*/
genJqSecretsReplacementSnippet = genJqSecretsReplacementSnippet' "_secret";
# Like genJqSecretsReplacementSnippet, but allows the name of the
# attr which identifies the secret to be changed.
genJqSecretsReplacementSnippet' = attr: set: output:
let
secrets = recursiveGetAttrWithJqPrefix set attr;
in ''
if [[ -h '${output}' ]]; then
rm '${output}'
fi
inherit_errexit_enabled=0
shopt -pq inherit_errexit && inherit_errexit_enabled=1
shopt -s inherit_errexit
''
+ concatStringsSep
"\n"
(imap1 (index: name: ''
secret${toString index}=$(<'${secrets.${name}}')
export secret${toString index}
'')
(attrNames secrets))
+ "\n"
+ "${pkgs.jq}/bin/jq >'${output}' '"
+ concatStringsSep
" | "
(imap1 (index: name: ''${name} = $ENV.secret${toString index}'')
(attrNames secrets))
+ ''
' <<'EOF'
${builtins.toJSON set}
EOF
(( ! $inherit_errexit_enabled )) && shopt -u inherit_errexit
'';
systemdUtils = {
lib = import ./systemd-lib.nix { inherit lib config pkgs; };
unitOptions = import ./systemd-unit-options.nix { inherit lib systemdUtils; };
};
}