lix/src/nix-build/nix-build.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

604 lines
20 KiB
C++
Executable file

#include <cstring>
#include <fstream>
#include <iostream>
#include <filesystem>
#include <regex>
#include <sstream>
#include <vector>
#include <map>
#include <nlohmann/json.hpp>
#include "parsed-derivations.hh"
#include "store-api.hh"
#include "local-fs-store.hh"
#include "globals.hh"
#include "derivations.hh"
#include "affinity.hh"
#include "util.hh"
#include "shared.hh"
#include "path-with-outputs.hh"
#include "eval.hh"
#include "eval-inline.hh"
#include "get-drvs.hh"
#include "common-eval-args.hh"
#include "attr-path.hh"
#include "legacy.hh"
using namespace nix;
using namespace std::string_literals;
extern char * * environ __attribute__((weak));
/* Recreate the effect of the perl shellwords function, breaking up a
* string into arguments like a shell word, including escapes
*/
std::vector<string> shellwords(const string & s)
{
std::regex whitespace("^(\\s+).*");
auto begin = s.cbegin();
std::vector<string> res;
std::string cur;
enum state {
sBegin,
sQuote
};
state st = sBegin;
auto it = begin;
for (; it != s.cend(); ++it) {
if (st == sBegin) {
std::smatch match;
if (regex_search(it, s.cend(), match, whitespace)) {
cur.append(begin, it);
res.push_back(cur);
cur.clear();
it = match[1].second;
begin = it;
}
}
switch (*it) {
case '"':
cur.append(begin, it);
begin = it + 1;
st = st == sBegin ? sQuote : sBegin;
break;
case '\\':
/* perl shellwords mostly just treats the next char as part of the string with no special processing */
cur.append(begin, it);
begin = ++it;
break;
}
}
cur.append(begin, it);
if (!cur.empty()) res.push_back(cur);
return res;
}
static void main_nix_build(int argc, char * * argv)
{
auto dryRun = false;
auto runEnv = std::regex_search(argv[0], std::regex("nix-shell$"));
auto pure = false;
auto fromArgs = false;
auto packages = false;
// Same condition as bash uses for interactive shells
auto interactive = isatty(STDIN_FILENO) && isatty(STDERR_FILENO);
Strings attrPaths;
Strings left;
RepairFlag repair = NoRepair;
Path gcRoot;
BuildMode buildMode = bmNormal;
bool readStdin = false;
std::string envCommand; // interactive shell
Strings envExclude;
auto myName = runEnv ? "nix-shell" : "nix-build";
auto inShebang = false;
std::string script;
std::vector<string> savedArgs;
AutoDelete tmpDir(createTempDir("", myName));
std::string outLink = "./result";
// List of environment variables kept for --pure
std::set<string> keepVars{
"HOME", "USER", "LOGNAME", "DISPLAY", "PATH", "TERM", "IN_NIX_SHELL",
"NIX_SHELL_PRESERVE_PROMPT", "TZ", "PAGER", "NIX_BUILD_SHELL", "SHLVL",
"http_proxy", "https_proxy", "ftp_proxy", "all_proxy", "no_proxy"
};
Strings args;
for (int i = 1; i < argc; ++i)
args.push_back(argv[i]);
// Heuristic to see if we're invoked as a shebang script, namely,
// if we have at least one argument, it's the name of an
// executable file, and it starts with "#!".
if (runEnv && argc > 1) {
script = argv[1];
try {
auto lines = tokenizeString<Strings>(readFile(script), "\n");
if (std::regex_search(lines.front(), std::regex("^#!"))) {
lines.pop_front();
inShebang = true;
for (int i = 2; i < argc; ++i)
savedArgs.push_back(argv[i]);
args.clear();
for (auto line : lines) {
line = chomp(line);
std::smatch match;
if (std::regex_match(line, match, std::regex("^#!\\s*nix-shell (.*)$")))
for (const auto & word : shellwords(match[1].str()))
args.push_back(word);
}
}
} catch (SysError &) { }
}
struct MyArgs : LegacyArgs, MixEvalArgs
{
using LegacyArgs::LegacyArgs;
};
MyArgs myArgs(myName, [&](Strings::iterator & arg, const Strings::iterator & end) {
if (*arg == "--help") {
deletePath(tmpDir);
showManPage(myName);
}
else if (*arg == "--version")
printVersion(myName);
else if (*arg == "--add-drv-link" || *arg == "--indirect")
; // obsolete
else if (*arg == "--no-out-link" || *arg == "--no-link")
outLink = (Path) tmpDir + "/result";
else if (*arg == "--attr" || *arg == "-A")
attrPaths.push_back(getArg(*arg, arg, end));
else if (*arg == "--drv-link")
getArg(*arg, arg, end); // obsolete
else if (*arg == "--out-link" || *arg == "-o")
outLink = getArg(*arg, arg, end);
else if (*arg == "--add-root")
gcRoot = getArg(*arg, arg, end);
else if (*arg == "--dry-run")
dryRun = true;
else if (*arg == "--repair") {
repair = Repair;
buildMode = bmRepair;
}
else if (*arg == "--run-env") // obsolete
runEnv = true;
else if (runEnv && (*arg == "--command" || *arg == "--run")) {
if (*arg == "--run")
interactive = false;
envCommand = getArg(*arg, arg, end) + "\nexit";
}
else if (*arg == "--check")
buildMode = bmCheck;
else if (*arg == "--exclude")
envExclude.push_back(getArg(*arg, arg, end));
else if (*arg == "--expr" || *arg == "-E")
fromArgs = true;
else if (*arg == "--pure") pure = true;
else if (*arg == "--impure") pure = false;
else if (runEnv && (*arg == "--packages" || *arg == "-p"))
packages = true;
else if (inShebang && *arg == "-i") {
auto interpreter = getArg(*arg, arg, end);
interactive = false;
auto execArgs = "";
// Überhack to support Perl. Perl examines the shebang and
// executes it unless it contains the string "perl" or "indir",
// or (undocumented) argv[0] does not contain "perl". Exploit
// the latter by doing "exec -a".
if (std::regex_search(interpreter, std::regex("perl")))
execArgs = "-a PERL";
std::ostringstream joined;
for (const auto & i : savedArgs)
joined << shellEscape(i) << ' ';
if (std::regex_search(interpreter, std::regex("ruby"))) {
// Hack for Ruby. Ruby also examines the shebang. It tries to
// read the shebang to understand which packages to read from. Since
// this is handled via nix-shell -p, we wrap our ruby script execution
// in ruby -e 'load' which ignores the shebangs.
envCommand = (format("exec %1% %2% -e 'load(ARGV.shift)' -- %3% %4%") % execArgs % interpreter % shellEscape(script) % joined.str()).str();
} else {
envCommand = (format("exec %1% %2% %3% %4%") % execArgs % interpreter % shellEscape(script) % joined.str()).str();
}
}
else if (*arg == "--keep")
keepVars.insert(getArg(*arg, arg, end));
else if (*arg == "-")
readStdin = true;
else if (*arg != "" && arg->at(0) == '-')
return false;
else
left.push_back(*arg);
return true;
});
myArgs.parseCmdline(args);
if (packages && fromArgs)
throw UsageError("'-p' and '-E' are mutually exclusive");
auto store = openStore();
auto evalStore = myArgs.evalStoreUrl ? openStore(*myArgs.evalStoreUrl) : store;
auto state = std::make_unique<EvalState>(myArgs.searchPath, evalStore, store);
state->repair = repair;
auto autoArgs = myArgs.getAutoArgs(*state);
if (runEnv) {
auto newArgs = state->allocBindings(autoArgs->size() + 1);
auto tru = state->allocValue();
mkBool(*tru, true);
newArgs->push_back(Attr(state->symbols.create("inNixShell"), tru));
for (auto & i : *autoArgs) newArgs->push_back(i);
newArgs->sort();
autoArgs = newArgs;
}
if (packages) {
std::ostringstream joined;
joined << "{...}@args: with import <nixpkgs> args; (pkgs.runCommandCC or pkgs.runCommand) \"shell\" { buildInputs = [ ";
for (const auto & i : left)
joined << '(' << i << ") ";
joined << "]; } \"\"";
fromArgs = true;
left = {joined.str()};
} else if (!fromArgs) {
if (left.empty() && runEnv && pathExists("shell.nix"))
left = {"shell.nix"};
if (left.empty())
left = {"default.nix"};
}
if (runEnv)
setenv("IN_NIX_SHELL", pure ? "pure" : "impure", 1);
DrvInfos drvs;
/* Parse the expressions. */
std::vector<Expr *> exprs;
if (readStdin)
exprs = {state->parseStdin()};
else
for (auto i : left) {
if (fromArgs)
exprs.push_back(state->parseExprFromString(i, absPath(".")));
else {
auto absolute = i;
try {
absolute = canonPath(absPath(i), true);
} catch (Error & e) {};
auto [path, outputNames] = parsePathWithOutputs(absolute);
if (evalStore->isStorePath(path) && hasSuffix(path, ".drv"))
drvs.push_back(DrvInfo(*state, evalStore, absolute));
else
/* If we're in a #! script, interpret filenames
relative to the script. */
exprs.push_back(state->parseExprFromFile(resolveExprPath(state->checkSourcePath(lookupFileArg(*state,
inShebang && !packages ? absPath(i, absPath(dirOf(script))) : i)))));
}
}
/* Evaluate them into derivations. */
if (attrPaths.empty()) attrPaths = {""};
for (auto e : exprs) {
Value vRoot;
state->eval(e, vRoot);
for (auto & i : attrPaths) {
Value & v(*findAlongAttrPath(*state, i, *autoArgs, vRoot).first);
state->forceValue(v);
getDerivations(*state, v, "", *autoArgs, drvs, false);
}
}
state->printStats();
auto buildPaths = [&](const std::vector<StorePathWithOutputs> & paths0) {
auto paths = toDerivedPaths(paths0);
/* Note: we do this even when !printMissing to efficiently
fetch binary cache data. */
uint64_t downloadSize, narSize;
StorePathSet willBuild, willSubstitute, unknown;
store->queryMissing(paths,
willBuild, willSubstitute, unknown, downloadSize, narSize);
if (settings.printMissing)
printMissing(ref<Store>(store), willBuild, willSubstitute, unknown, downloadSize, narSize);
if (!dryRun)
store->buildPaths(paths, buildMode, evalStore);
};
if (runEnv) {
if (drvs.size() != 1)
throw UsageError("nix-shell requires a single derivation");
auto & drvInfo = drvs.front();
auto drv = evalStore->derivationFromPath(evalStore->parseStorePath(drvInfo.queryDrvPath()));
std::vector<StorePathWithOutputs> pathsToBuild;
RealisedPath::Set pathsToCopy;
/* Figure out what bash shell to use. If $NIX_BUILD_SHELL
is not set, then build bashInteractive from
<nixpkgs>. */
auto shell = getEnv("NIX_BUILD_SHELL");
if (!shell) {
try {
auto expr = state->parseExprFromString("(import <nixpkgs> {}).bashInteractive", absPath("."));
Value v;
state->eval(expr, v);
auto drv = getDerivation(*state, v, false);
if (!drv)
throw Error("the 'bashInteractive' attribute in <nixpkgs> did not evaluate to a derivation");
auto bashDrv = store->parseStorePath(drv->queryDrvPath());
pathsToBuild.push_back({bashDrv});
pathsToCopy.insert(bashDrv);
shell = drv->queryOutPath() + "/bin/bash";
} catch (Error & e) {
logError(e.info());
notice("will use bash from your environment");
shell = "bash";
}
}
// Build or fetch all dependencies of the derivation.
for (const auto & input : drv.inputDrvs)
if (std::all_of(envExclude.cbegin(), envExclude.cend(),
[&](const string & exclude) { return !std::regex_search(store->printStorePath(input.first), std::regex(exclude)); }))
{
pathsToBuild.push_back({input.first, input.second});
pathsToCopy.insert(input.first);
}
for (const auto & src : drv.inputSrcs) {
pathsToBuild.push_back({src});
pathsToCopy.insert(src);
}
buildPaths(pathsToBuild);
if (dryRun) return;
if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations)) {
auto resolvedDrv = drv.tryResolve(*store);
assert(resolvedDrv && "Successfully resolved the derivation");
drv = *resolvedDrv;
}
// Set the environment.
auto env = getEnv();
auto tmp = getEnv("TMPDIR");
if (!tmp) tmp = getEnv("XDG_RUNTIME_DIR").value_or("/tmp");
if (pure) {
decltype(env) newEnv;
for (auto & i : env)
if (keepVars.count(i.first))
newEnv.emplace(i);
env = newEnv;
// NixOS hack: prevent /etc/bashrc from sourcing /etc/profile.
env["__ETC_PROFILE_SOURCED"] = "1";
}
env["NIX_BUILD_TOP"] = env["TMPDIR"] = env["TEMPDIR"] = env["TMP"] = env["TEMP"] = *tmp;
env["NIX_STORE"] = store->storeDir;
env["NIX_BUILD_CORES"] = std::to_string(settings.buildCores);
auto passAsFile = tokenizeString<StringSet>(get(drv.env, "passAsFile").value_or(""));
bool keepTmp = false;
int fileNr = 0;
for (auto & var : drv.env)
if (passAsFile.count(var.first)) {
keepTmp = true;
string fn = ".attr-" + std::to_string(fileNr++);
Path p = (Path) tmpDir + "/" + fn;
writeFile(p, var.second);
env[var.first + "Path"] = p;
} else
env[var.first] = var.second;
std::string structuredAttrsRC;
if (env.count("__json")) {
StorePathSet inputs;
for (auto & [depDrvPath, wantedDepOutputs] : drv.inputDrvs) {
auto outputs = evalStore->queryPartialDerivationOutputMap(depDrvPath);
for (auto & i : wantedDepOutputs) {
auto o = outputs.at(i);
store->computeFSClosure(*o, inputs);
}
}
ParsedDerivation parsedDrv(
StorePath(store->parseStorePath(drvInfo.queryDrvPath())),
drv
);
if (auto structAttrs = parsedDrv.prepareStructuredAttrs(*store, inputs)) {
auto json = structAttrs.value();
structuredAttrsRC = writeStructuredAttrsShell(json);
auto attrsJSON = (Path) tmpDir + "/.attrs.json";
writeFile(attrsJSON, json.dump());
auto attrsSH = (Path) tmpDir + "/.attrs.sh";
writeFile(attrsSH, structuredAttrsRC);
env["NIX_ATTRS_SH_FILE"] = attrsSH;
env["NIX_ATTRS_JSON_FILE"] = attrsJSON;
keepTmp = true;
}
}
/* Run a shell using the derivation's environment. For
convenience, source $stdenv/setup to setup additional
environment variables and shell functions. Also don't
lose the current $PATH directories. */
auto rcfile = (Path) tmpDir + "/rc";
std::string rc = fmt(
R"(_nix_shell_clean_tmpdir() { rm -rf %1%; }; )"s +
(keepTmp ?
"trap _nix_shell_clean_tmpdir EXIT; "
"exitHooks+=(_nix_shell_clean_tmpdir); "
"failureHooks+=(_nix_shell_clean_tmpdir); ":
"_nix_shell_clean_tmpdir; ") +
(pure ? "" : "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;") +
"%2%"
// always clear PATH.
// when nix-shell is run impure, we rehydrate it with the `p=$PATH` above
"unset PATH;"
"dontAddDisableDepTrack=1;\n"
+ structuredAttrsRC +
"\n[ -e $stdenv/setup ] && source $stdenv/setup; "
"%3%"
"PATH=%4%:\"$PATH\"; "
"SHELL=%5%; "
"set +e; "
R"s([ -n "$PS1" -a -z "$NIX_SHELL_PRESERVE_PROMPT" ] && PS1='\n\[\033[1;32m\][nix-shell:\w]\$\[\033[0m\] '; )s"
"if [ \"$(type -t runHook)\" = function ]; then runHook shellHook; fi; "
"unset NIX_ENFORCE_PURITY; "
"shopt -u nullglob; "
"unset TZ; %6%"
"shopt -s execfail;"
"%7%",
shellEscape(tmpDir),
(pure ? "" : "p=$PATH; "),
(pure ? "" : "PATH=$PATH:$p; unset p; "),
shellEscape(dirOf(*shell)),
shellEscape(*shell),
(getenv("TZ") ? (string("export TZ=") + shellEscape(getenv("TZ")) + "; ") : ""),
envCommand);
vomit("Sourcing nix-shell with file %s and contents:\n%s", rcfile, rc);
writeFile(rcfile, rc);
Strings envStrs;
for (auto & i : env)
envStrs.push_back(i.first + "=" + i.second);
auto args = interactive
? Strings{"bash", "--rcfile", rcfile}
: Strings{"bash", rcfile};
auto envPtrs = stringsToCharPtrs(envStrs);
environ = envPtrs.data();
auto argPtrs = stringsToCharPtrs(args);
restoreProcessContext();
logger->stop();
execvp(shell->c_str(), argPtrs.data());
throw SysError("executing shell '%s'", *shell);
}
else {
std::vector<StorePathWithOutputs> pathsToBuild;
std::vector<std::pair<StorePath, std::string>> pathsToBuildOrdered;
RealisedPath::Set drvsToCopy;
std::map<StorePath, std::pair<size_t, StringSet>> drvMap;
for (auto & drvInfo : drvs) {
auto drvPath = store->parseStorePath(drvInfo.queryDrvPath());
auto outputName = drvInfo.queryOutputName();
if (outputName == "")
throw Error("derivation '%s' lacks an 'outputName' attribute", store->printStorePath(drvPath));
pathsToBuild.push_back({drvPath, {outputName}});
pathsToBuildOrdered.push_back({drvPath, {outputName}});
drvsToCopy.insert(drvPath);
auto i = drvMap.find(drvPath);
if (i != drvMap.end())
i->second.second.insert(outputName);
else
drvMap[drvPath] = {drvMap.size(), {outputName}};
}
buildPaths(pathsToBuild);
if (dryRun) return;
std::vector<StorePath> outPaths;
for (auto & [drvPath, outputName] : pathsToBuildOrdered) {
auto & [counter, _wantedOutputs] = drvMap.at({drvPath});
std::string drvPrefix = outLink;
if (counter)
drvPrefix += fmt("-%d", counter + 1);
auto builtOutputs = evalStore->queryPartialDerivationOutputMap(drvPath);
auto maybeOutputPath = builtOutputs.at(outputName);
assert(maybeOutputPath);
auto outputPath = *maybeOutputPath;
if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
std::string symlink = drvPrefix;
if (outputName != "out") symlink += "-" + outputName;
store2->addPermRoot(outputPath, absPath(symlink));
}
outPaths.push_back(outputPath);
}
logger->stop();
for (auto & path : outPaths)
std::cout << store->printStorePath(path) << '\n';
}
}
static RegisterLegacyCommand r_nix_build("nix-build", main_nix_build);
static RegisterLegacyCommand r_nix_shell("nix-shell", main_nix_build);