mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-14 18:26:16 +02:00
12bb8cdd38
This sets up infrastructure in libutil to allow for signing other than by a secret key in memory. #9076 uses this to implement remote signing. (Split from that PR to allow reviewing in smaller chunks.) Co-Authored-By: Raito Bezarius <masterancpp@gmail.com>
426 lines
14 KiB
C++
426 lines
14 KiB
C++
#include "globals.hh"
|
||
#include "current-process.hh"
|
||
#include "archive.hh"
|
||
#include "args.hh"
|
||
#include "users.hh"
|
||
#include "abstract-setting-to-json.hh"
|
||
#include "compute-levels.hh"
|
||
|
||
#include <algorithm>
|
||
#include <map>
|
||
#include <mutex>
|
||
#include <thread>
|
||
#include <dlfcn.h>
|
||
#include <sys/utsname.h>
|
||
|
||
#include <nlohmann/json.hpp>
|
||
|
||
#ifdef __GLIBC__
|
||
# include <gnu/lib-names.h>
|
||
# include <nss.h>
|
||
# include <dlfcn.h>
|
||
#endif
|
||
|
||
#if __APPLE__
|
||
# include "processes.hh"
|
||
#endif
|
||
|
||
#include "config-impl.hh"
|
||
|
||
#ifdef __APPLE__
|
||
#include <sys/sysctl.h>
|
||
#endif
|
||
|
||
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(getEnvNonEmpty("NIX_STORE_DIR").value_or(getEnvNonEmpty("NIX_STORE").value_or(NIX_STORE_DIR))))
|
||
, nixDataDir(canonPath(getEnvNonEmpty("NIX_DATA_DIR").value_or(NIX_DATA_DIR)))
|
||
, nixLogDir(canonPath(getEnvNonEmpty("NIX_LOG_DIR").value_or(NIX_LOG_DIR)))
|
||
, nixStateDir(canonPath(getEnvNonEmpty("NIX_STATE_DIR").value_or(NIX_STATE_DIR)))
|
||
, nixConfDir(canonPath(getEnvNonEmpty("NIX_CONF_DIR").value_or(NIX_CONF_DIR)))
|
||
, nixUserConfFiles(getUserConfigFiles())
|
||
, nixBinDir(canonPath(getEnvNonEmpty("NIX_BIN_DIR").value_or(NIX_BIN_DIR)))
|
||
, nixManDir(canonPath(NIX_MAN_DIR))
|
||
, nixDaemonSocketFile(canonPath(getEnvNonEmpty("NIX_DAEMON_SOCKET_PATH").value_or(nixStateDir + DEFAULT_SOCKET_PATH)))
|
||
{
|
||
buildUsersGroup = getuid() == 0 ? "nixbld" : "";
|
||
allowSymlinkedStore = getEnv("NIX_IGNORE_SYMLINK_STORE") == "1";
|
||
|
||
auto sslOverride = getEnv("NIX_SSL_CERT_FILE").value_or(getEnv("SSL_CERT_FILE").value_or(""));
|
||
if (sslOverride != "")
|
||
caFile = sslOverride;
|
||
|
||
/* 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
|
||
|
||
/* Set the build hook location
|
||
|
||
For builds we perform a self-invocation, so Nix has to be self-aware.
|
||
That is, it has to know where it is installed. We don't think it's sentient.
|
||
|
||
Normally, nix is installed according to `nixBinDir`, which is set at compile time,
|
||
but can be overridden. This makes for a great default that works even if this
|
||
code is linked as a library into some other program whose main is not aware
|
||
that it might need to be a build remote hook.
|
||
|
||
However, it may not have been installed at all. For example, if it's a static build,
|
||
there's a good chance that it has been moved out of its installation directory.
|
||
That makes `nixBinDir` useless. Instead, we'll query the OS for the path to the
|
||
current executable, using `getSelfExe()`.
|
||
|
||
As a last resort, we resort to `PATH`. Hopefully we find a `nix` there that's compatible.
|
||
If you're porting Nix to a new platform, that might be good enough for a while, but
|
||
you'll want to improve `getSelfExe()` to work on your platform.
|
||
*/
|
||
std::string nixExePath = nixBinDir + "/nix";
|
||
if (!pathExists(nixExePath)) {
|
||
nixExePath = getSelfExe().value_or("nix");
|
||
}
|
||
buildHook = {
|
||
nixExePath,
|
||
"__build-remote",
|
||
};
|
||
}
|
||
|
||
void loadConfFile()
|
||
{
|
||
auto applyConfigFile = [&](const Path & path) {
|
||
try {
|
||
std::string contents = readFile(path);
|
||
globalConfig.applyConfig(contents, path);
|
||
} catch (SysError &) { }
|
||
};
|
||
|
||
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++) {
|
||
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<std::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()
|
||
{
|
||
const unsigned int concurrency = std::max(1U, std::thread::hardware_concurrency());
|
||
const unsigned int maxCPU = getMaxCPU();
|
||
|
||
if (maxCPU > 0)
|
||
return maxCPU;
|
||
else
|
||
return concurrency;
|
||
}
|
||
|
||
#if __APPLE__
|
||
static bool hasVirt() {
|
||
|
||
int hasVMM;
|
||
int hvSupport;
|
||
size_t size;
|
||
|
||
size = sizeof(hasVMM);
|
||
if (sysctlbyname("kern.hv_vmm_present", &hasVMM, &size, NULL, 0) == 0) {
|
||
if (hasVMM)
|
||
return false;
|
||
}
|
||
|
||
// whether the kernel and hardware supports virt
|
||
size = sizeof(hvSupport);
|
||
if (sysctlbyname("kern.hv_support", &hvSupport, &size, NULL, 0) == 0) {
|
||
return hvSupport == 1;
|
||
} else {
|
||
return false;
|
||
}
|
||
}
|
||
#endif
|
||
|
||
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"};
|
||
|
||
#if __linux__
|
||
features.insert("uid-range");
|
||
#endif
|
||
|
||
#if __linux__
|
||
if (access("/dev/kvm", R_OK | W_OK) == 0)
|
||
features.insert("kvm");
|
||
#endif
|
||
|
||
#if __APPLE__
|
||
if (hasVirt())
|
||
features.insert("apple-virt");
|
||
#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 can’t force processes from executing
|
||
// x86_64 in aarch64 environments or vice versa since they can
|
||
// always exec with their own binary preferences.
|
||
if (std::string{SYSTEM} == "aarch64-darwin" &&
|
||
runProgram(RunOptions {.program = "arch", .args = {"-arch", "x86_64", "/usr/bin/true"}, .mergeStderrToStdout = true}).first == 0)
|
||
extraPlatforms.insert("x86_64-darwin");
|
||
#endif
|
||
|
||
return extraPlatforms;
|
||
}
|
||
|
||
bool Settings::isWSL1()
|
||
{
|
||
struct utsname utsbuf;
|
||
uname(&utsbuf);
|
||
// WSL1 uses -Microsoft suffix
|
||
// WSL2 uses -microsoft-standard suffix
|
||
return hasSuffix(utsbuf.release, "-Microsoft");
|
||
}
|
||
|
||
Path Settings::getDefaultSSLCertFile()
|
||
{
|
||
for (auto & fn : {"/etc/ssl/certs/ca-certificates.crt", "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"})
|
||
if (pathAccessible(fn)) return fn;
|
||
return "";
|
||
}
|
||
|
||
const std::string nixVersion = PACKAGE_VERSION;
|
||
|
||
NLOHMANN_JSON_SERIALIZE_ENUM(SandboxMode, {
|
||
{SandboxMode::smEnabled, true},
|
||
{SandboxMode::smRelaxed, "relaxed"},
|
||
{SandboxMode::smDisabled, false},
|
||
});
|
||
|
||
template<> SandboxMode BaseSetting<SandboxMode>::parse(const std::string & str) const
|
||
{
|
||
if (str == "true") return smEnabled;
|
||
else if (str == "relaxed") return smRelaxed;
|
||
else if (str == "false") return smDisabled;
|
||
else throw UsageError("option '%s' has invalid value '%s'", name, str);
|
||
}
|
||
|
||
template<> struct BaseSetting<SandboxMode>::trait
|
||
{
|
||
static constexpr bool appendable = 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 = {[this]() { override(smEnabled); }}
|
||
});
|
||
args.addFlag({
|
||
.longName = "no-" + name,
|
||
.description = "Disable sandboxing.",
|
||
.category = category,
|
||
.handler = {[this]() { override(smDisabled); }}
|
||
});
|
||
args.addFlag({
|
||
.longName = "relaxed-" + name,
|
||
.description = "Enable sandboxing, but allow builds to disable it.",
|
||
.category = category,
|
||
.handler = {[this]() { override(smRelaxed); }}
|
||
});
|
||
}
|
||
|
||
unsigned int MaxBuildJobsSetting::parse(const std::string & str) const
|
||
{
|
||
if (str == "auto") return std::max(1U, std::thread::hardware_concurrency());
|
||
else {
|
||
if (auto n = string2Int<decltype(value)>(str))
|
||
return *n;
|
||
else
|
||
throw UsageError("configuration setting '%s' should be 'auto' or an integer", name);
|
||
}
|
||
}
|
||
|
||
|
||
Paths PluginFilesSetting::parse(const std::string & str) const
|
||
{
|
||
if (pluginsLoaded)
|
||
throw UsageError("plugin-files set after plugins were loaded, you may need to move the flag before the subcommand");
|
||
return BaseSetting<Paths>::parse(str);
|
||
}
|
||
|
||
|
||
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;
|
||
}
|
||
|
||
static void preloadNSS()
|
||
{
|
||
/* builtin:fetchurl can trigger a DNS lookup, which with glibc can trigger a dynamic library load of
|
||
one of the glibc NSS libraries in a sandboxed child, which will fail unless the library's already
|
||
been loaded in the parent. So we force a lookup of an invalid domain to force the NSS machinery to
|
||
load its lookup libraries in the parent before any child gets a chance to. */
|
||
static std::once_flag dns_resolve_flag;
|
||
|
||
std::call_once(dns_resolve_flag, []() {
|
||
#ifdef __GLIBC__
|
||
/* On linux, glibc will run every lookup through the nss layer.
|
||
* That means every lookup goes, by default, through nscd, which acts as a local
|
||
* cache.
|
||
* Because we run builds in a sandbox, we also remove access to nscd otherwise
|
||
* lookups would leak into the sandbox.
|
||
*
|
||
* But now we have a new problem, we need to make sure the nss_dns backend that
|
||
* does the dns lookups when nscd is not available is loaded or available.
|
||
*
|
||
* We can't make it available without leaking nix's environment, so instead we'll
|
||
* load the backend, and configure nss so it does not try to run dns lookups
|
||
* through nscd.
|
||
*
|
||
* This is technically only used for builtins:fetch* functions so we only care
|
||
* about dns.
|
||
*
|
||
* All other platforms are unaffected.
|
||
*/
|
||
if (!dlopen(LIBNSS_DNS_SO, RTLD_NOW))
|
||
warn("unable to load nss_dns backend");
|
||
// FIXME: get hosts entry from nsswitch.conf.
|
||
__nss_configure_lookup("hosts", "files dns");
|
||
#endif
|
||
});
|
||
}
|
||
|
||
static bool initLibStoreDone = false;
|
||
|
||
void assertLibStoreInitialized() {
|
||
if (!initLibStoreDone) {
|
||
printError("The program must call nix::initNix() before calling any libstore library functions.");
|
||
abort();
|
||
};
|
||
}
|
||
|
||
void initLibStore() {
|
||
|
||
initLibUtil();
|
||
|
||
loadConfFile();
|
||
|
||
preloadNSS();
|
||
|
||
/* On macOS, don't use the per-session TMPDIR (as set e.g. by
|
||
sshd). This breaks build users because they don't have access
|
||
to the TMPDIR, in particular in ‘nix-store --serve’. */
|
||
#if __APPLE__
|
||
if (hasPrefix(getEnv("TMPDIR").value_or("/tmp"), "/var/folders/"))
|
||
unsetenv("TMPDIR");
|
||
#endif
|
||
|
||
initLibStoreDone = true;
|
||
}
|
||
|
||
|
||
}
|