lix/src/libstore/globals.cc
regnat af99941279 Make experimental-features a proper type
Rather than having them plain strings scattered through the whole
codebase, create an enum containing all the known experimental features.

This means that
- Nix can now `warn` when an unkwown experimental feature is passed
  (making it much nicer to spot typos and spot deprecated features)
- It’s now easy to remove a feature altogether (once the feature isn’t
  experimental anymore or is dropped) by just removing the field for the
  enum and letting the compiler point us to all the now invalid usages
  of it.
2021-10-26 07:02:31 +02:00

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#include "globals.hh"
#include "util.hh"
#include "archive.hh"
#include "args.hh"
#include "abstract-setting-to-json.hh"
#include "compute-levels.hh"
#include <algorithm>
#include <map>
#include <thread>
#include <dlfcn.h>
#include <sys/utsname.h>
#include <nlohmann/json.hpp>
namespace nix {
/* The default location of the daemon socket, relative to nixStateDir.
The socket is in a directory to allow you to control access to the
Nix daemon by setting the mode/ownership of the directory
appropriately. (This wouldn't work on the socket itself since it
must be deleted and recreated on startup.) */
#define DEFAULT_SOCKET_PATH "/daemon-socket/socket"
Settings settings;
static GlobalConfig::Register rSettings(&settings);
Settings::Settings()
: nixPrefix(NIX_PREFIX)
, nixStore(canonPath(getEnv("NIX_STORE_DIR").value_or(getEnv("NIX_STORE").value_or(NIX_STORE_DIR))))
, nixDataDir(canonPath(getEnv("NIX_DATA_DIR").value_or(NIX_DATA_DIR)))
, nixLogDir(canonPath(getEnv("NIX_LOG_DIR").value_or(NIX_LOG_DIR)))
, nixStateDir(canonPath(getEnv("NIX_STATE_DIR").value_or(NIX_STATE_DIR)))
, nixConfDir(canonPath(getEnv("NIX_CONF_DIR").value_or(NIX_CONF_DIR)))
, nixUserConfFiles(getUserConfigFiles())
, nixLibexecDir(canonPath(getEnv("NIX_LIBEXEC_DIR").value_or(NIX_LIBEXEC_DIR)))
, nixBinDir(canonPath(getEnv("NIX_BIN_DIR").value_or(NIX_BIN_DIR)))
, nixManDir(canonPath(NIX_MAN_DIR))
, nixDaemonSocketFile(canonPath(getEnv("NIX_DAEMON_SOCKET_PATH").value_or(nixStateDir + DEFAULT_SOCKET_PATH)))
{
buildUsersGroup = getuid() == 0 ? "nixbld" : "";
lockCPU = getEnv("NIX_AFFINITY_HACK") == "1";
allowSymlinkedStore = getEnv("NIX_IGNORE_SYMLINK_STORE") == "1";
caFile = getEnv("NIX_SSL_CERT_FILE").value_or(getEnv("SSL_CERT_FILE").value_or(""));
if (caFile == "") {
for (auto & fn : {"/etc/ssl/certs/ca-certificates.crt", "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"})
if (pathExists(fn)) {
caFile = fn;
break;
}
}
/* Backwards compatibility. */
auto s = getEnv("NIX_REMOTE_SYSTEMS");
if (s) {
Strings ss;
for (auto & p : tokenizeString<Strings>(*s, ":"))
ss.push_back("@" + p);
builders = concatStringsSep(" ", ss);
}
#if defined(__linux__) && defined(SANDBOX_SHELL)
sandboxPaths = tokenizeString<StringSet>("/bin/sh=" SANDBOX_SHELL);
#endif
/* chroot-like behavior from Apple's sandbox */
#if __APPLE__
sandboxPaths = tokenizeString<StringSet>("/System/Library/Frameworks /System/Library/PrivateFrameworks /bin/sh /bin/bash /private/tmp /private/var/tmp /usr/lib");
allowedImpureHostPrefixes = tokenizeString<StringSet>("/System/Library /usr/lib /dev /bin/sh");
#endif
}
void loadConfFile()
{
globalConfig.applyConfigFile(settings.nixConfDir + "/nix.conf");
/* We only want to send overrides to the daemon, i.e. stuff from
~/.nix/nix.conf or the command line. */
globalConfig.resetOverridden();
auto files = settings.nixUserConfFiles;
for (auto file = files.rbegin(); file != files.rend(); file++) {
globalConfig.applyConfigFile(*file);
}
auto nixConfEnv = getEnv("NIX_CONFIG");
if (nixConfEnv.has_value()) {
globalConfig.applyConfig(nixConfEnv.value(), "NIX_CONFIG");
}
}
std::vector<Path> getUserConfigFiles()
{
// Use the paths specified in NIX_USER_CONF_FILES if it has been defined
auto nixConfFiles = getEnv("NIX_USER_CONF_FILES");
if (nixConfFiles.has_value()) {
return tokenizeString<std::vector<string>>(nixConfFiles.value(), ":");
}
// Use the paths specified by the XDG spec
std::vector<Path> files;
auto dirs = getConfigDirs();
for (auto & dir : dirs) {
files.insert(files.end(), dir + "/nix/nix.conf");
}
return files;
}
unsigned int Settings::getDefaultCores()
{
return std::max(1U, std::thread::hardware_concurrency());
}
StringSet Settings::getDefaultSystemFeatures()
{
/* For backwards compatibility, accept some "features" that are
used in Nixpkgs to route builds to certain machines but don't
actually require anything special on the machines. */
StringSet features{"nixos-test", "benchmark", "big-parallel", "recursive-nix"};
#if __linux__
if (access("/dev/kvm", R_OK | W_OK) == 0)
features.insert("kvm");
#endif
return features;
}
StringSet Settings::getDefaultExtraPlatforms()
{
StringSet extraPlatforms;
if (std::string{SYSTEM} == "x86_64-linux" && !isWSL1())
extraPlatforms.insert("i686-linux");
#if __linux__
StringSet levels = computeLevels();
for (auto iter = levels.begin(); iter != levels.end(); ++iter)
extraPlatforms.insert(*iter + "-linux");
#elif __APPLE__
// Rosetta 2 emulation layer can run x86_64 binaries on aarch64
// machines. Note that we cant force processes from executing
// x86_64 in aarch64 environments or vice versa since they can
// always exec with their own binary preferences.
if (pathExists("/Library/Apple/System/Library/LaunchDaemons/com.apple.oahd.plist") ||
pathExists("/System/Library/LaunchDaemons/com.apple.oahd.plist")) {
if (std::string{SYSTEM} == "x86_64-darwin")
extraPlatforms.insert("aarch64-darwin");
else if (std::string{SYSTEM} == "aarch64-darwin")
extraPlatforms.insert("x86_64-darwin");
}
#endif
return extraPlatforms;
}
bool Settings::isExperimentalFeatureEnabled(const ExperimentalFeature & feature)
{
auto & f = experimentalFeatures.get();
return std::find(f.begin(), f.end(), feature) != f.end();
}
void Settings::requireExperimentalFeature(const ExperimentalFeature & feature)
{
if (!isExperimentalFeatureEnabled(feature))
throw MissingExperimentalFeature(feature);
}
bool Settings::isWSL1()
{
struct utsname utsbuf;
uname(&utsbuf);
// WSL1 uses -Microsoft suffix
// WSL2 uses -microsoft-standard suffix
return hasSuffix(utsbuf.release, "-Microsoft");
}
const string nixVersion = PACKAGE_VERSION;
NLOHMANN_JSON_SERIALIZE_ENUM(SandboxMode, {
{SandboxMode::smEnabled, true},
{SandboxMode::smRelaxed, "relaxed"},
{SandboxMode::smDisabled, false},
});
template<> void BaseSetting<SandboxMode>::set(const std::string & str, bool append)
{
if (str == "true") value = smEnabled;
else if (str == "relaxed") value = smRelaxed;
else if (str == "false") value = smDisabled;
else throw UsageError("option '%s' has invalid value '%s'", name, str);
}
template<> bool BaseSetting<SandboxMode>::isAppendable()
{
return false;
}
template<> std::string BaseSetting<SandboxMode>::to_string() const
{
if (value == smEnabled) return "true";
else if (value == smRelaxed) return "relaxed";
else if (value == smDisabled) return "false";
else abort();
}
template<> void BaseSetting<SandboxMode>::convertToArg(Args & args, const std::string & category)
{
args.addFlag({
.longName = name,
.description = "Enable sandboxing.",
.category = category,
.handler = {[=]() { override(smEnabled); }}
});
args.addFlag({
.longName = "no-" + name,
.description = "Disable sandboxing.",
.category = category,
.handler = {[=]() { override(smDisabled); }}
});
args.addFlag({
.longName = "relaxed-" + name,
.description = "Enable sandboxing, but allow builds to disable it.",
.category = category,
.handler = {[=]() { override(smRelaxed); }}
});
}
void MaxBuildJobsSetting::set(const std::string & str, bool append)
{
if (str == "auto") value = std::max(1U, std::thread::hardware_concurrency());
else {
if (auto n = string2Int<decltype(value)>(str))
value = *n;
else
throw UsageError("configuration setting '%s' should be 'auto' or an integer", name);
}
}
void PluginFilesSetting::set(const std::string & str, bool append)
{
if (pluginsLoaded)
throw UsageError("plugin-files set after plugins were loaded, you may need to move the flag before the subcommand");
BaseSetting<Paths>::set(str, append);
}
void initPlugins()
{
assert(!settings.pluginFiles.pluginsLoaded);
for (const auto & pluginFile : settings.pluginFiles.get()) {
Paths pluginFiles;
try {
auto ents = readDirectory(pluginFile);
for (const auto & ent : ents)
pluginFiles.emplace_back(pluginFile + "/" + ent.name);
} catch (SysError & e) {
if (e.errNo != ENOTDIR)
throw;
pluginFiles.emplace_back(pluginFile);
}
for (const auto & file : pluginFiles) {
/* handle is purposefully leaked as there may be state in the
DSO needed by the action of the plugin. */
void *handle =
dlopen(file.c_str(), RTLD_LAZY | RTLD_LOCAL);
if (!handle)
throw Error("could not dynamically open plugin file '%s': %s", file, dlerror());
}
}
/* Since plugins can add settings, try to re-apply previously
unknown settings. */
globalConfig.reapplyUnknownSettings();
globalConfig.warnUnknownSettings();
/* Tell the user if they try to set plugin-files after we've already loaded */
settings.pluginFiles.pluginsLoaded = true;
}
}