nix-super/src/libstore/globals.cc
2021-01-08 12:22:21 +01:00

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#include "globals.hh"
#include "util.hh"
#include "archive.hh"
#include "args.hh"
#include "abstract-setting-to-json.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.resetOverriden();
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()
{
if (std::string{SYSTEM} == "x86_64-linux" && !isWSL1())
return StringSet{"i686-linux"};
#if __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.
else if (pathExists("/Library/Apple/System/Library/LaunchDaemons/com.apple.oahd.plist")) {
if (std::string{SYSTEM} == "x86_64-darwin")
return StringSet{"aarch64-darwin"};
else if (std::string{SYSTEM} == "aarch64-darwin")
return StringSet{"x86_64-darwin"};
else
return StringSet{};
}
#endif
else
return StringSet{};
}
bool Settings::isExperimentalFeatureEnabled(const std::string & name)
{
auto & f = experimentalFeatures.get();
return std::find(f.begin(), f.end(), name) != f.end();
}
void Settings::requireExperimentalFeature(const std::string & name)
{
if (!isExperimentalFeatureEnabled(name))
throw Error("experimental Nix feature '%1%' is disabled; use '--experimental-features %1%' to override", name);
}
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 initPlugins()
{
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();
}
}