lix/src/nix/main.cc
pennae 8775be3393 store Symbols in a table as well, like positions
this slightly increases the amount of memory used for any given symbol, but this
increase is more than made up for if the symbol is referenced more than once in
the EvalState that holds it. on average every symbol should be referenced at
least twice (once to introduce a binding, once to use it), so we expect no
increase in memory on average.

symbol tables are limited to 2³² entries like position tables, and similar
arguments apply to why overflow is not likely: 2³² symbols would require as many
string instances (at 24 bytes each) and map entries (at 24 bytes or more each,
assuming that the map holds on average at most one item per bucket as the docs
say). a full symbol table would require at least 192GB of memory just for
symbols, which is well out of reach. (an ofborg eval of nixpks today creates
less than a million symbols!)
2022-04-21 21:56:31 +02:00

399 lines
11 KiB
C++

#include <algorithm>
#include "command.hh"
#include "common-args.hh"
#include "eval.hh"
#include "globals.hh"
#include "legacy.hh"
#include "shared.hh"
#include "store-api.hh"
#include "filetransfer.hh"
#include "finally.hh"
#include "loggers.hh"
#include "markdown.hh"
#include <sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <netinet/in.h>
#include <nlohmann/json.hpp>
extern std::string chrootHelperName;
void chrootHelper(int argc, char * * argv);
namespace nix {
/* Check if we have a non-loopback/link-local network interface. */
static bool haveInternet()
{
struct ifaddrs * addrs;
if (getifaddrs(&addrs))
return true;
Finally free([&]() { freeifaddrs(addrs); });
for (auto i = addrs; i; i = i->ifa_next) {
if (!i->ifa_addr) continue;
if (i->ifa_addr->sa_family == AF_INET) {
if (ntohl(((sockaddr_in *) i->ifa_addr)->sin_addr.s_addr) != INADDR_LOOPBACK) {
return true;
}
} else if (i->ifa_addr->sa_family == AF_INET6) {
if (!IN6_IS_ADDR_LOOPBACK(&((sockaddr_in6 *) i->ifa_addr)->sin6_addr) &&
!IN6_IS_ADDR_LINKLOCAL(&((sockaddr_in6 *) i->ifa_addr)->sin6_addr))
return true;
}
}
return false;
}
std::string programPath;
char * * savedArgv;
struct HelpRequested { };
struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
{
bool useNet = true;
bool refresh = false;
bool showVersion = false;
NixArgs() : MultiCommand(RegisterCommand::getCommandsFor({})), MixCommonArgs("nix")
{
categories.clear();
categories[Command::catDefault] = "Main commands";
categories[catSecondary] = "Infrequently used commands";
categories[catUtility] = "Utility/scripting commands";
categories[catNixInstallation] = "Commands for upgrading or troubleshooting your Nix installation";
addFlag({
.longName = "help",
.description = "Show usage information.",
.handler = {[&]() { throw HelpRequested(); }},
});
addFlag({
.longName = "print-build-logs",
.shortName = 'L',
.description = "Print full build logs on standard error.",
.category = loggingCategory,
.handler = {[&]() {setLogFormat(LogFormat::barWithLogs); }},
});
addFlag({
.longName = "version",
.description = "Show version information.",
.handler = {[&]() { showVersion = true; }},
});
addFlag({
.longName = "offline",
.aliases = {"no-net"}, // FIXME: remove
.description = "Disable substituters and consider all previously downloaded files up-to-date.",
.handler = {[&]() { useNet = false; }},
});
addFlag({
.longName = "refresh",
.description = "Consider all previously downloaded files out-of-date.",
.handler = {[&]() { refresh = true; }},
});
}
std::map<std::string, std::vector<std::string>> aliases = {
{"add-to-store", {"store", "add-path"}},
{"cat-nar", {"nar", "cat"}},
{"cat-store", {"store", "cat"}},
{"copy-sigs", {"store", "copy-sigs"}},
{"dev-shell", {"develop"}},
{"diff-closures", {"store", "diff-closures"}},
{"dump-path", {"store", "dump-path"}},
{"hash-file", {"hash", "file"}},
{"hash-path", {"hash", "path"}},
{"ls-nar", {"nar", "ls"}},
{"ls-store", {"store", "ls"}},
{"make-content-addressable", {"store", "make-content-addressed"}},
{"optimise-store", {"store", "optimise"}},
{"ping-store", {"store", "ping"}},
{"sign-paths", {"store", "sign"}},
{"to-base16", {"hash", "to-base16"}},
{"to-base32", {"hash", "to-base32"}},
{"to-base64", {"hash", "to-base64"}},
{"verify", {"store", "verify"}},
};
bool aliasUsed = false;
Strings::iterator rewriteArgs(Strings & args, Strings::iterator pos) override
{
if (aliasUsed || command || pos == args.end()) return pos;
auto arg = *pos;
auto i = aliases.find(arg);
if (i == aliases.end()) return pos;
warn("'%s' is a deprecated alias for '%s'",
arg, concatStringsSep(" ", i->second));
pos = args.erase(pos);
for (auto j = i->second.rbegin(); j != i->second.rend(); ++j)
pos = args.insert(pos, *j);
aliasUsed = true;
return pos;
}
std::string description() override
{
return "a tool for reproducible and declarative configuration management";
}
std::string doc() override
{
return
#include "nix.md"
;
}
// Plugins may add new subcommands.
void pluginsInited() override
{
commands = RegisterCommand::getCommandsFor({});
}
};
/* Render the help for the specified subcommand to stdout using
lowdown. */
static void showHelp(std::vector<std::string> subcommand, MultiCommand & toplevel)
{
auto mdName = subcommand.empty() ? "nix" : fmt("nix3-%s", concatStringsSep("-", subcommand));
evalSettings.restrictEval = false;
evalSettings.pureEval = false;
EvalState state({}, openStore("dummy://"));
auto vGenerateManpage = state.allocValue();
state.eval(state.parseExprFromString(
#include "generate-manpage.nix.gen.hh"
, "/"), *vGenerateManpage);
auto vUtils = state.allocValue();
state.cacheFile(
"/utils.nix", "/utils.nix",
state.parseExprFromString(
#include "utils.nix.gen.hh"
, "/"),
*vUtils);
auto attrs = state.buildBindings(16);
attrs.alloc("command").mkString(toplevel.toJSON().dump());
auto vRes = state.allocValue();
state.callFunction(*vGenerateManpage, state.allocValue()->mkAttrs(attrs), *vRes, noPos);
auto attr = vRes->attrs->get(state.symbols.create(mdName + ".md"));
if (!attr)
throw UsageError("Nix has no subcommand '%s'", concatStringsSep("", subcommand));
auto markdown = state.forceString(*attr->value);
RunPager pager;
std::cout << renderMarkdownToTerminal(markdown) << "\n";
}
struct CmdHelp : Command
{
std::vector<std::string> subcommand;
CmdHelp()
{
expectArgs({
.label = "subcommand",
.handler = {&subcommand},
});
}
std::string description() override
{
return "show help about `nix` or a particular subcommand";
}
std::string doc() override
{
return
#include "help.md"
;
}
void run() override
{
assert(parent);
MultiCommand * toplevel = parent;
while (toplevel->parent) toplevel = toplevel->parent;
showHelp(subcommand, *toplevel);
}
};
static auto rCmdHelp = registerCommand<CmdHelp>("help");
void mainWrapped(int argc, char * * argv)
{
savedArgv = argv;
/* The chroot helper needs to be run before any threads have been
started. */
if (argc > 0 && argv[0] == chrootHelperName) {
chrootHelper(argc, argv);
return;
}
initNix();
initGC();
#if __linux__
if (getuid() == 0) {
try {
saveMountNamespace();
if (unshare(CLONE_NEWNS) == -1)
throw SysError("setting up a private mount namespace");
} catch (Error & e) { }
}
#endif
programPath = argv[0];
auto programName = std::string(baseNameOf(programPath));
{
auto legacy = (*RegisterLegacyCommand::commands)[programName];
if (legacy) return legacy(argc, argv);
}
evalSettings.pureEval = true;
setLogFormat("bar");
settings.verboseBuild = false;
if (isatty(STDERR_FILENO)) {
verbosity = lvlNotice;
} else {
verbosity = lvlInfo;
}
Finally f([] { logger->stop(); });
NixArgs args;
if (argc == 2 && std::string(argv[1]) == "__dump-args") {
std::cout << args.toJSON().dump() << "\n";
return;
}
if (argc == 2 && std::string(argv[1]) == "__dump-builtins") {
settings.experimentalFeatures = {Xp::Flakes, Xp::FetchClosure};
evalSettings.pureEval = false;
EvalState state({}, openStore("dummy://"));
auto res = nlohmann::json::object();
auto builtins = state.baseEnv.values[0]->attrs;
for (auto & builtin : *builtins) {
auto b = nlohmann::json::object();
if (!builtin.value->isPrimOp()) continue;
auto primOp = builtin.value->primOp;
if (!primOp->doc) continue;
b["arity"] = primOp->arity;
b["args"] = primOp->args;
b["doc"] = trim(stripIndentation(primOp->doc));
res[state.symbols[builtin.name]] = std::move(b);
}
std::cout << res.dump() << "\n";
return;
}
Finally printCompletions([&]()
{
if (completions) {
switch (completionType) {
case ctNormal:
std::cout << "normal\n"; break;
case ctFilenames:
std::cout << "filenames\n"; break;
case ctAttrs:
std::cout << "attrs\n"; break;
}
for (auto & s : *completions)
std::cout << s.completion << "\t" << s.description << "\n";
}
});
try {
args.parseCmdline(argvToStrings(argc, argv));
} catch (HelpRequested &) {
std::vector<std::string> subcommand;
MultiCommand * command = &args;
while (command) {
if (command && command->command) {
subcommand.push_back(command->command->first);
command = dynamic_cast<MultiCommand *>(&*command->command->second);
} else
break;
}
showHelp(subcommand, args);
return;
} catch (UsageError &) {
if (!completions) throw;
}
if (completions) return;
if (args.showVersion) {
printVersion(programName);
return;
}
if (!args.command)
throw UsageError("no subcommand specified");
if (args.command->first != "repl"
&& args.command->first != "doctor"
&& args.command->first != "upgrade-nix")
settings.requireExperimentalFeature(Xp::NixCommand);
if (args.useNet && !haveInternet()) {
warn("you don't have Internet access; disabling some network-dependent features");
args.useNet = false;
}
if (!args.useNet) {
// FIXME: should check for command line overrides only.
if (!settings.useSubstitutes.overridden)
settings.useSubstitutes = false;
if (!settings.tarballTtl.overridden)
settings.tarballTtl = std::numeric_limits<unsigned int>::max();
if (!fileTransferSettings.tries.overridden)
fileTransferSettings.tries = 0;
if (!fileTransferSettings.connectTimeout.overridden)
fileTransferSettings.connectTimeout = 1;
}
if (args.refresh) {
settings.tarballTtl = 0;
settings.ttlNegativeNarInfoCache = 0;
settings.ttlPositiveNarInfoCache = 0;
}
args.command->second->prepare();
args.command->second->run();
}
}
int main(int argc, char * * argv)
{
// Increase the default stack size for the evaluator and for
// libstdc++'s std::regex.
nix::setStackSize(64 * 1024 * 1024);
return nix::handleExceptions(argv[0], [&]() {
nix::mainWrapped(argc, argv);
});
}