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Diffstat (limited to 'src/libexpr/primops.cc')
| -rw-r--r-- | src/libexpr/primops.cc | 2077 |
1 files changed, 2077 insertions, 0 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc new file mode 100644 index 000000000..615cc8138 --- /dev/null +++ b/src/libexpr/primops.cc @@ -0,0 +1,2077 @@ +#include "archive.hh" +#include "derivations.hh" +#include "download.hh" +#include "eval-inline.hh" +#include "eval.hh" +#include "globals.hh" +#include "json-to-value.hh" +#include "names.hh" +#include "store-api.hh" +#include "util.hh" +#include "json.hh" +#include "value-to-json.hh" +#include "value-to-xml.hh" +#include "primops.hh" + +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <algorithm> +#include <cstring> +#include <regex> +#include <dlfcn.h> + + +namespace nix { + + +/************************************************************* + * Miscellaneous + *************************************************************/ + + +/* Decode a context string ‘!<name>!<path>’ into a pair <path, + name>. */ +std::pair<string, string> decodeContext(const string & s) +{ + if (s.at(0) == '!') { + size_t index = s.find("!", 1); + return std::pair<string, string>(string(s, index + 1), string(s, 1, index - 1)); + } else + return std::pair<string, string>(s.at(0) == '/' ? s: string(s, 1), ""); +} + + +InvalidPathError::InvalidPathError(const Path & path) : + EvalError(format("path ‘%1%’ is not valid") % path), path(path) {} + +void EvalState::realiseContext(const PathSet & context) +{ + PathSet drvs; + for (auto & i : context) { + std::pair<string, string> decoded = decodeContext(i); + Path ctx = decoded.first; + assert(store->isStorePath(ctx)); + if (!store->isValidPath(ctx)) + throw InvalidPathError(ctx); + if (!decoded.second.empty() && nix::isDerivation(ctx)) + drvs.insert(decoded.first + "!" + decoded.second); + } + if (!drvs.empty()) { + if (!settings.enableImportFromDerivation) + throw EvalError(format("attempted to realize ‘%1%’ during evaluation but 'allow-import-from-derivation' is false") % *(drvs.begin())); + /* For performance, prefetch all substitute info. */ + PathSet willBuild, willSubstitute, unknown; + unsigned long long downloadSize, narSize; + store->queryMissing(drvs, willBuild, willSubstitute, unknown, downloadSize, narSize); + store->buildPaths(drvs); + } +} + + +/* Load and evaluate an expression from path specified by the + argument. */ +static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[1], context); + + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot import ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % path % e.path % pos); + } + + path = state.checkSourcePath(path); + + if (state.store->isStorePath(path) && state.store->isValidPath(path) && isDerivation(path)) { + Derivation drv = readDerivation(path); + Value & w = *state.allocValue(); + state.mkAttrs(w, 3 + drv.outputs.size()); + Value * v2 = state.allocAttr(w, state.sDrvPath); + mkString(*v2, path, {"=" + path}); + v2 = state.allocAttr(w, state.sName); + mkString(*v2, drv.env["name"]); + Value * outputsVal = + state.allocAttr(w, state.symbols.create("outputs")); + state.mkList(*outputsVal, drv.outputs.size()); + unsigned int outputs_index = 0; + + for (const auto & o : drv.outputs) { + v2 = state.allocAttr(w, state.symbols.create(o.first)); + mkString(*v2, o.second.path, {"!" + o.first + "!" + path}); + outputsVal->listElems()[outputs_index] = state.allocValue(); + mkString(*(outputsVal->listElems()[outputs_index++]), o.first); + } + w.attrs->sort(); + Value fun; + state.evalFile(settings.nixDataDir + "/nix/corepkgs/imported-drv-to-derivation.nix", fun); + state.forceFunction(fun, pos); + mkApp(v, fun, w); + state.forceAttrs(v, pos); + } else { + state.forceAttrs(*args[0]); + if (args[0]->attrs->empty()) + state.evalFile(path, v); + else { + Env * env = &state.allocEnv(args[0]->attrs->size()); + env->up = &state.baseEnv; + + StaticEnv staticEnv(false, &state.staticBaseEnv); + + unsigned int displ = 0; + for (auto & attr : *args[0]->attrs) { + staticEnv.vars[attr.name] = displ; + env->values[displ++] = attr.value; + } + + Activity act(*logger, lvlTalkative, format("evaluating file ‘%1%’") % path); + Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv); + + e->eval(state, *env, v); + } + } +} + + +/* Want reasonable symbol names, so extern C */ +/* !!! Should we pass the Pos or the file name too? */ +extern "C" typedef void (*ValueInitializer)(EvalState & state, Value & v); + +/* Load a ValueInitializer from a DSO and return whatever it initializes */ +static void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[0], context); + + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot import ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % path % e.path % pos); + } + + path = state.checkSourcePath(path); + + string sym = state.forceStringNoCtx(*args[1], pos); + + void *handle = dlopen(path.c_str(), RTLD_LAZY | RTLD_LOCAL); + if (!handle) + throw EvalError(format("could not open ‘%1%’: %2%") % path % dlerror()); + + dlerror(); + ValueInitializer func = (ValueInitializer) dlsym(handle, sym.c_str()); + if(!func) { + char *message = dlerror(); + if (message) + throw EvalError(format("could not load symbol ‘%1%’ from ‘%2%’: %3%") % sym % path % message); + else + throw EvalError(format("symbol ‘%1%’ from ‘%2%’ resolved to NULL when a function pointer was expected") + % sym % path); + } + + (func)(state, v); + + /* We don't dlclose because v may be a primop referencing a function in the shared object file */ +} + + +/* Execute a program and parse its output */ +static void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + auto elems = args[0]->listElems(); + auto count = args[0]->listSize(); + if (count == 0) { + throw EvalError(format("at least one argument to 'exec' required, at %1%") % pos); + } + PathSet context; + auto program = state.coerceToString(pos, *elems[0], context, false, false); + Strings commandArgs; + for (unsigned int i = 1; i < args[0]->listSize(); ++i) { + commandArgs.emplace_back(state.coerceToString(pos, *elems[i], context, false, false)); + } + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot execute ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % program % e.path % pos); + } + + auto output = runProgram(program, true, commandArgs); + Expr * parsed; + try { + parsed = state.parseExprFromString(output, pos.file); + } catch (Error & e) { + e.addPrefix(format("While parsing the output from ‘%1%’, at %2%\n") % program % pos); + throw; + } + try { + state.eval(parsed, v); + } catch (Error & e) { + e.addPrefix(format("While evaluating the output from ‘%1%’, at %2%\n") % program % pos); + throw; + } +} + + +/* Return a string representing the type of the expression. */ +static void prim_typeOf(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + string t; + switch (args[0]->type) { + case tInt: t = "int"; break; + case tBool: t = "bool"; break; + case tString: t = "string"; break; + case tPath: t = "path"; break; + case tNull: t = "null"; break; + case tAttrs: t = "set"; break; + case tList1: case tList2: case tListN: t = "list"; break; + case tLambda: + case tPrimOp: + case tPrimOpApp: + t = "lambda"; + break; + case tExternal: + t = args[0]->external->typeOf(); + break; + case tFloat: t = "float"; break; + default: abort(); + } + mkString(v, state.symbols.create(t)); +} + + +/* Determine whether the argument is the null value. */ +static void prim_isNull(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tNull); +} + + +/* Determine whether the argument is a function. */ +static void prim_isFunction(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tLambda); +} + + +/* Determine whether the argument is an integer. */ +static void prim_isInt(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tInt); +} + +/* Determine whether the argument is a float. */ +static void prim_isFloat(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tFloat); +} + +/* Determine whether the argument is a string. */ +static void prim_isString(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tString); +} + + +/* Determine whether the argument is a Boolean. */ +static void prim_isBool(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tBool); +} + + +struct CompareValues +{ + bool operator () (const Value * v1, const Value * v2) const + { + if (v1->type == tFloat && v2->type == tInt) + return v1->fpoint < v2->integer; + if (v1->type == tInt && v2->type == tFloat) + return v1->integer < v2->fpoint; + if (v1->type != v2->type) + throw EvalError(format("cannot compare %1% with %2%") % showType(*v1) % showType(*v2)); + switch (v1->type) { + case tInt: + return v1->integer < v2->integer; + case tFloat: + return v1->fpoint < v2->fpoint; + case tString: + return strcmp(v1->string.s, v2->string.s) < 0; + case tPath: + return strcmp(v1->path, v2->path) < 0; + default: + throw EvalError(format("cannot compare %1% with %2%") % showType(*v1) % showType(*v2)); + } + } +}; + + +#if HAVE_BOEHMGC +typedef list<Value *, gc_allocator<Value *> > ValueList; +#else +typedef list<Value *> ValueList; +#endif + + +static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + Activity act(*logger, lvlDebug, "finding dependencies"); + + state.forceAttrs(*args[0], pos); + + /* Get the start set. */ + Bindings::iterator startSet = + args[0]->attrs->find(state.symbols.create("startSet")); + if (startSet == args[0]->attrs->end()) + throw EvalError(format("attribute ‘startSet’ required, at %1%") % pos); + state.forceList(*startSet->value, pos); + + ValueList workSet; + for (unsigned int n = 0; n < startSet->value->listSize(); ++n) + workSet.push_back(startSet->value->listElems()[n]); + + /* Get the operator. */ + Bindings::iterator op = + args[0]->attrs->find(state.symbols.create("operator")); + if (op == args[0]->attrs->end()) + throw EvalError(format("attribute ‘operator’ required, at %1%") % pos); + state.forceValue(*op->value); + + /* Construct the closure by applying the operator to element of + `workSet', adding the result to `workSet', continuing until + no new elements are found. */ + ValueList res; + // `doneKeys' doesn't need to be a GC root, because its values are + // reachable from res. + set<Value *, CompareValues> doneKeys; + while (!workSet.empty()) { + Value * e = *(workSet.begin()); + workSet.pop_front(); + + state.forceAttrs(*e, pos); + + Bindings::iterator key = + e->attrs->find(state.symbols.create("key")); + if (key == e->attrs->end()) + throw EvalError(format("attribute ‘key’ required, at %1%") % pos); + state.forceValue(*key->value); + + if (doneKeys.find(key->value) != doneKeys.end()) continue; + doneKeys.insert(key->value); + res.push_back(e); + + /* Call the `operator' function with `e' as argument. */ + Value call; + mkApp(call, *op->value, *e); + state.forceList(call, pos); + + /* Add the values returned by the operator to the work set. */ + for (unsigned int n = 0; n < call.listSize(); ++n) { + state.forceValue(*call.listElems()[n]); + workSet.push_back(call.listElems()[n]); + } + } + + /* Create the result list. */ + state.mkList(v, res.size()); + unsigned int n = 0; + for (auto & i : res) + v.listElems()[n++] = i; +} + + +static void prim_abort(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + throw Abort(format("evaluation aborted with the following error message: ‘%1%’") % s); +} + + +static void prim_throw(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + throw ThrownError(s); +} + + +static void prim_addErrorContext(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + try { + state.forceValue(*args[1]); + v = *args[1]; + } catch (Error & e) { + PathSet context; + e.addPrefix(format("%1%\n") % state.coerceToString(pos, *args[0], context)); + throw; + } +} + + +/* Try evaluating the argument. Success => {success=true; value=something;}, + * else => {success=false; value=false;} */ +static void prim_tryEval(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.mkAttrs(v, 2); + try { + state.forceValue(*args[0]); + v.attrs->push_back(Attr(state.sValue, args[0])); + mkBool(*state.allocAttr(v, state.symbols.create("success")), true); + } catch (AssertionError & e) { + mkBool(*state.allocAttr(v, state.sValue), false); + mkBool(*state.allocAttr(v, state.symbols.create("success")), false); + } + v.attrs->sort(); +} + + +/* Return an environment variable. Use with care. */ +static void prim_getEnv(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string name = state.forceStringNoCtx(*args[0], pos); + mkString(v, state.restricted ? "" : getEnv(name)); +} + + +/* Evaluate the first argument, then return the second argument. */ +static void prim_seq(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + state.forceValue(*args[1]); + v = *args[1]; +} + + +/* Evaluate the first argument deeply (i.e. recursing into lists and + attrsets), then return the second argument. */ +static void prim_deepSeq(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValueDeep(*args[0]); + state.forceValue(*args[1]); + v = *args[1]; +} + + +/* Evaluate the first expression and print it on standard error. Then + return the second expression. Useful for debugging. */ +static void prim_trace(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + if (args[0]->type == tString) + printError(format("trace: %1%") % args[0]->string.s); + else + printError(format("trace: %1%") % *args[0]); + state.forceValue(*args[1]); + v = *args[1]; +} + + +void prim_valueSize(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + /* We're not forcing the argument on purpose. */ + mkInt(v, valueSize(*args[0])); +} + + +/************************************************************* + * Derivations + *************************************************************/ + + +/* Construct (as a unobservable side effect) a Nix derivation + expression that performs the derivation described by the argument + set. Returns the original set extended with the following + attributes: `outPath' containing the primary output path of the + derivation; `drvPath' containing the path of the Nix expression; + and `type' set to `derivation' to indicate that this is a + derivation. */ +static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + Activity act(*logger, lvlVomit, "evaluating derivation"); + + state.forceAttrs(*args[0], pos); + + /* Figure out the name first (for stack backtraces). */ + Bindings::iterator attr = args[0]->attrs->find(state.sName); + if (attr == args[0]->attrs->end()) + throw EvalError(format("required attribute ‘name’ missing, at %1%") % pos); + string drvName; + Pos & posDrvName(*attr->pos); + try { + drvName = state.forceStringNoCtx(*attr->value, pos); + } catch (Error & e) { + e.addPrefix(format("while evaluating the derivation attribute ‘name’ at %1%:\n") % posDrvName); + throw; + } + + /* Check whether attributes should be passed as a JSON file. */ + std::ostringstream jsonBuf; + std::unique_ptr<JSONObject> jsonObject; + attr = args[0]->attrs->find(state.sStructuredAttrs); + if (attr != args[0]->attrs->end() && state.forceBool(*attr->value, pos)) + jsonObject = std::make_unique<JSONObject>(jsonBuf); + + /* Check whether null attributes should be ignored. */ + bool ignoreNulls = false; + attr = args[0]->attrs->find(state.sIgnoreNulls); + if (attr != args[0]->attrs->end()) + ignoreNulls = state.forceBool(*attr->value, pos); + + /* Build the derivation expression by processing the attributes. */ + Derivation drv; + + PathSet context; + + string outputHash, outputHashAlgo; + bool outputHashRecursive = false; + + StringSet outputs; + outputs.insert("out"); + + for (auto & i : args[0]->attrs->lexicographicOrder()) { + if (i->name == state.sIgnoreNulls) continue; + string key = i->name; + Activity act(*logger, lvlVomit, format("processing attribute ‘%1%’") % key); + + auto handleHashMode = [&](const std::string & s) { + if (s == "recursive") outputHashRecursive = true; + else if (s == "flat") outputHashRecursive = false; + else throw EvalError("invalid value ‘%s’ for ‘outputHashMode’ attribute, at %s", s, posDrvName); + }; + + auto handleOutputs = [&](const Strings & ss) { + outputs.clear(); + for (auto & j : ss) { + if (outputs.find(j) != outputs.end()) + throw EvalError(format("duplicate derivation output ‘%1%’, at %2%") % j % posDrvName); + /* !!! Check whether j is a valid attribute + name. */ + /* Derivations cannot be named ‘drv’, because + then we'd have an attribute ‘drvPath’ in + the resulting set. */ + if (j == "drv") + throw EvalError(format("invalid derivation output name ‘drv’, at %1%") % posDrvName); + outputs.insert(j); + } + if (outputs.empty()) + throw EvalError(format("derivation cannot have an empty set of outputs, at %1%") % posDrvName); + }; + + try { + + if (ignoreNulls) { + state.forceValue(*i->value); + if (i->value->type == tNull) continue; + } + + /* The `args' attribute is special: it supplies the + command-line arguments to the builder. */ + if (key == "args") { + state.forceList(*i->value, pos); + for (unsigned int n = 0; n < i->value->listSize(); ++n) { + string s = state.coerceToString(posDrvName, *i->value->listElems()[n], context, true); + drv.args.push_back(s); + } + } + + /* All other attributes are passed to the builder through + the environment. */ + else { + + if (jsonObject) { + + if (i->name == state.sStructuredAttrs) continue; + + auto placeholder(jsonObject->placeholder(key)); + printValueAsJSON(state, true, *i->value, placeholder, context); + + if (i->name == state.sBuilder) + drv.builder = state.forceString(*i->value, context, posDrvName); + else if (i->name == state.sSystem) + drv.platform = state.forceStringNoCtx(*i->value, posDrvName); + else if (i->name == state.sName) + drvName = state.forceStringNoCtx(*i->value, posDrvName); + else if (key == "outputHash") + outputHash = state.forceStringNoCtx(*i->value, posDrvName); + else if (key == "outputHashAlgo") + outputHashAlgo = state.forceStringNoCtx(*i->value, posDrvName); + else if (key == "outputHashMode") + handleHashMode(state.forceStringNoCtx(*i->value, posDrvName)); + else if (key == "outputs") { + /* Require ‘outputs’ to be a list of strings. */ + state.forceList(*i->value, posDrvName); + Strings ss; + for (unsigned int n = 0; n < i->value->listSize(); ++n) + ss.emplace_back(state.forceStringNoCtx(*i->value->listElems()[n], posDrvName)); + handleOutputs(ss); + } + + } else { + auto s = state.coerceToString(posDrvName, *i->value, context, true); + drv.env.emplace(key, s); + if (i->name == state.sBuilder) drv.builder = s; + else if (i->name == state.sSystem) drv.platform = s; + else if (i->name == state.sName) { + drvName = s; + printMsg(lvlVomit, format("derivation name is ‘%1%’") % drvName); + } + else if (key == "outputHash") outputHash = s; + else if (key == "outputHashAlgo") outputHashAlgo = s; + else if (key == "outputHashMode") handleHashMode(s); + else if (key == "outputs") + handleOutputs(tokenizeString<Strings>(s)); + } + + } + + } catch (Error & e) { + e.addPrefix(format("while evaluating the attribute ‘%1%’ of the derivation ‘%2%’ at %3%:\n") + % key % drvName % posDrvName); + throw; + } + } + + if (jsonObject) { + jsonObject.reset(); + drv.env.emplace("__json", jsonBuf.str()); + } + + /* Everything in the context of the strings in the derivation + attributes should be added as dependencies of the resulting + derivation. */ + for (auto & path : context) { + + /* Paths marked with `=' denote that the path of a derivation + is explicitly passed to the builder. Since that allows the + builder to gain access to every path in the dependency + graph of the derivation (including all outputs), all paths + in the graph must be added to this derivation's list of + inputs to ensure that they are available when the builder + runs. */ + if (path.at(0) == '=') { + /* !!! This doesn't work if readOnlyMode is set. */ + PathSet refs; + state.store->computeFSClosure(string(path, 1), refs); + for (auto & j : refs) { + drv.inputSrcs.insert(j); + if (isDerivation(j)) + drv.inputDrvs[j] = state.store->queryDerivationOutputNames(j); + } + } + + /* See prim_unsafeDiscardOutputDependency. */ + else if (path.at(0) == '~') + drv.inputSrcs.insert(string(path, 1)); + + /* Handle derivation outputs of the form ‘!<name>!<path>’. */ + else if (path.at(0) == '!') { + std::pair<string, string> ctx = decodeContext(path); + drv.inputDrvs[ctx.first].insert(ctx.second); + } + + /* Handle derivation contexts returned by + ‘builtins.storePath’. */ + else if (isDerivation(path)) + drv.inputDrvs[path] = state.store->queryDerivationOutputNames(path); + + /* Otherwise it's a source file. */ + else + drv.inputSrcs.insert(path); + } + + /* Do we have all required attributes? */ + if (drv.builder == "") + throw EvalError(format("required attribute ‘builder’ missing, at %1%") % posDrvName); + if (drv.platform == "") + throw EvalError(format("required attribute ‘system’ missing, at %1%") % posDrvName); + + /* Check whether the derivation name is valid. */ + checkStoreName(drvName); + if (isDerivation(drvName)) + throw EvalError(format("derivation names are not allowed to end in ‘%1%’, at %2%") + % drvExtension % posDrvName); + + if (outputHash != "") { + /* Handle fixed-output derivations. */ + if (outputs.size() != 1 || *(outputs.begin()) != "out") + throw Error(format("multiple outputs are not supported in fixed-output derivations, at %1%") % posDrvName); + + HashType ht = parseHashType(outputHashAlgo); + if (ht == htUnknown) + throw EvalError(format("unknown hash algorithm ‘%1%’, at %2%") % outputHashAlgo % posDrvName); + Hash h = parseHash16or32(ht, outputHash); + outputHash = printHash(h); + if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo; + + Path outPath = state.store->makeFixedOutputPath(outputHashRecursive, h, drvName); + drv.env["out"] = outPath; + drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, outputHash); + } + + else { + /* Construct the "masked" store derivation, which is the final + one except that in the list of outputs, the output paths + are empty, and the corresponding environment variables have + an empty value. This ensures that changes in the set of + output names do get reflected in the hash. */ + for (auto & i : outputs) { + drv.env[i] = ""; + drv.outputs[i] = DerivationOutput("", "", ""); + } + + /* Use the masked derivation expression to compute the output + path. */ + Hash h = hashDerivationModulo(*state.store, drv); + + for (auto & i : drv.outputs) + if (i.second.path == "") { + Path outPath = state.store->makeOutputPath(i.first, h, drvName); + drv.env[i.first] = outPath; + i.second.path = outPath; + } + } + + /* Write the resulting term into the Nix store directory. */ + Path drvPath = writeDerivation(state.store, drv, drvName, state.repair); + + printMsg(lvlChatty, format("instantiated ‘%1%’ -> ‘%2%’") + % drvName % drvPath); + + /* Optimisation, but required in read-only mode! because in that + case we don't actually write store derivations, so we can't + read them later. */ + drvHashes[drvPath] = hashDerivationModulo(*state.store, drv); + + state.mkAttrs(v, 1 + drv.outputs.size()); + mkString(*state.allocAttr(v, state.sDrvPath), drvPath, {"=" + drvPath}); + for (auto & i : drv.outputs) { + mkString(*state.allocAttr(v, state.symbols.create(i.first)), + i.second.path, {"!" + i.first + "!" + drvPath}); + } + v.attrs->sort(); +} + + +/* Return a placeholder string for the specified output that will be + substituted by the corresponding output path at build time. For + example, ‘placeholder "out"’ returns the string + /1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9. At build + time, any occurence of this string in an derivation attribute will + be replaced with the concrete path in the Nix store of the output + ‘out’. */ +static void prim_placeholder(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + mkString(v, hashPlaceholder(state.forceStringNoCtx(*args[0], pos))); +} + + +/************************************************************* + * Paths + *************************************************************/ + + +/* Convert the argument to a path. !!! obsolete? */ +static void prim_toPath(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[0], context); + mkString(v, canonPath(path), context); +} + + +/* Allow a valid store path to be used in an expression. This is + useful in some generated expressions such as in nix-push, which + generates a call to a function with an already existing store path + as argument. You don't want to use `toPath' here because it copies + the path to the Nix store, which yields a copy like + /nix/store/newhash-oldhash-oldname. In the past, `toPath' had + special case behaviour for store paths, but that created weird + corner cases. */ +static void prim_storePath(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.checkSourcePath(state.coerceToPath(pos, *args[0], context)); + /* Resolve symlinks in ‘path’, unless ‘path’ itself is a symlink + directly in the store. The latter condition is necessary so + e.g. nix-push does the right thing. */ + if (!state.store->isStorePath(path)) path = canonPath(path, true); + if (!state.store->isInStore(path)) + throw EvalError(format("path ‘%1%’ is not in the Nix store, at %2%") % path % pos); + Path path2 = state.store->toStorePath(path); + if (!settings.readOnlyMode) + state.store->ensurePath(path2); + context.insert(path2); + mkString(v, path, context); +} + + +static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[0], context); + if (!context.empty()) + throw EvalError(format("string ‘%1%’ cannot refer to other paths, at %2%") % path % pos); + try { + mkBool(v, pathExists(state.checkSourcePath(path))); + } catch (SysError & e) { + /* Don't give away info from errors while canonicalising + ‘path’ in restricted mode. */ + mkBool(v, false); + } catch (RestrictedPathError & e) { + mkBool(v, false); + } +} + + +/* Return the base name of the given string, i.e., everything + following the last slash. */ +static void prim_baseNameOf(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + mkString(v, baseNameOf(state.coerceToString(pos, *args[0], context, false, false)), context); +} + + +/* Return the directory of the given path, i.e., everything before the + last slash. Return either a path or a string depending on the type + of the argument. */ +static void prim_dirOf(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path dir = dirOf(state.coerceToPath(pos, *args[0], context)); + if (args[0]->type == tPath) mkPath(v, dir.c_str()); else mkString(v, dir, context); +} + + +/* Return the contents of a file as a string. */ +static void prim_readFile(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[0], context); + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot read ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % path % e.path % pos); + } + string s = readFile(state.checkSourcePath(path)); + if (s.find((char) 0) != string::npos) + throw Error(format("the contents of the file ‘%1%’ cannot be represented as a Nix string") % path); + mkString(v, s.c_str()); +} + + +/* Find a file in the Nix search path. Used to implement <x> paths, + which are desugared to ‘findFile __nixPath "x"’. */ +static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + + SearchPath searchPath; + + for (unsigned int n = 0; n < args[0]->listSize(); ++n) { + Value & v2(*args[0]->listElems()[n]); + state.forceAttrs(v2, pos); + + string prefix; + Bindings::iterator i = v2.attrs->find(state.symbols.create("prefix")); + if (i != v2.attrs->end()) + prefix = state.forceStringNoCtx(*i->value, pos); + + i = v2.attrs->find(state.symbols.create("path")); + if (i == v2.attrs->end()) + throw EvalError(format("attribute ‘path’ missing, at %1%") % pos); + + PathSet context; + string path = state.coerceToString(pos, *i->value, context, false, false); + + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot find ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % path % e.path % pos); + } + + searchPath.emplace_back(prefix, path); + } + + string path = state.forceStringNoCtx(*args[1], pos); + + mkPath(v, state.checkSourcePath(state.findFile(searchPath, path, pos)).c_str()); +} + +/* Read a directory (without . or ..) */ +static void prim_readDir(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet ctx; + Path path = state.coerceToPath(pos, *args[0], ctx); + try { + state.realiseContext(ctx); + } catch (InvalidPathError & e) { + throw EvalError(format("cannot read ‘%1%’, since path ‘%2%’ is not valid, at %3%") + % path % e.path % pos); + } + + DirEntries entries = readDirectory(state.checkSourcePath(path)); + state.mkAttrs(v, entries.size()); + + for (auto & ent : entries) { + Value * ent_val = state.allocAttr(v, state.symbols.create(ent.name)); + if (ent.type == DT_UNKNOWN) + ent.type = getFileType(path + "/" + ent.name); + mkStringNoCopy(*ent_val, + ent.type == DT_REG ? "regular" : + ent.type == DT_DIR ? "directory" : + ent.type == DT_LNK ? "symlink" : + "unknown"); + } + + v.attrs->sort(); +} + + +/************************************************************* + * Creating files + *************************************************************/ + + +/* Convert the argument (which can be any Nix expression) to an XML + representation returned in a string. Not all Nix expressions can + be sensibly or completely represented (e.g., functions). */ +static void prim_toXML(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + std::ostringstream out; + PathSet context; + printValueAsXML(state, true, false, *args[0], out, context); + mkString(v, out.str(), context); +} + + +/* Convert the argument (which can be any Nix expression) to a JSON + string. Not all Nix expressions can be sensibly or completely + represented (e.g., functions). */ +static void prim_toJSON(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + std::ostringstream out; + PathSet context; + printValueAsJSON(state, true, *args[0], out, context); + mkString(v, out.str(), context); +} + + +/* Parse a JSON string to a value. */ +static void prim_fromJSON(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string s = state.forceStringNoCtx(*args[0], pos); + parseJSON(state, s, v); +} + + +/* Store a string in the Nix store as a source file that can be used + as an input by derivations. */ +static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string name = state.forceStringNoCtx(*args[0], pos); + string contents = state.forceString(*args[1], context, pos); + + PathSet refs; + + for (auto path : context) { + if (path.at(0) == '=') path = string(path, 1); + if (isDerivation(path)) { + /* See prim_unsafeDiscardOutputDependency. */ + if (path.at(0) != '~') + throw EvalError(format("in ‘toFile’: the file ‘%1%’ cannot refer to derivation outputs, at %2%") % name % pos); + path = string(path, 1); + } + refs.insert(path); + } + + Path storePath = settings.readOnlyMode + ? state.store->computeStorePathForText(name, contents, refs) + : state.store->addTextToStore(name, contents, refs, state.repair); + + /* Note: we don't need to add `context' to the context of the + result, since `storePath' itself has references to the paths + used in args[1]. */ + + mkString(v, storePath, {storePath}); +} + + +struct FilterFromExpr : PathFilter +{ + EvalState & state; + Value & filter; + Pos pos; + + FilterFromExpr(EvalState & state, Value & filter, const Pos & pos) + : state(state), filter(filter), pos(pos) + { + } + + bool operator () (const Path & path) + { + struct stat st; + if (lstat(path.c_str(), &st)) + throw SysError(format("getting attributes of path ‘%1%’") % path); + + /* Call the filter function. The first argument is the path, + the second is a string indicating the type of the file. */ + Value arg1; + mkString(arg1, path); + + Value fun2; + state.callFunction(filter, arg1, fun2, noPos); + + Value arg2; + mkString(arg2, + S_ISREG(st.st_mode) ? "regular" : + S_ISDIR(st.st_mode) ? "directory" : + S_ISLNK(st.st_mode) ? "symlink" : + "unknown" /* not supported, will fail! */); + + Value res; + state.callFunction(fun2, arg2, res, noPos); + + return state.forceBool(res, pos); + } +}; + + +static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(pos, *args[1], context); + if (!context.empty()) + throw EvalError(format("string ‘%1%’ cannot refer to other paths, at %2%") % path % pos); + + state.forceValue(*args[0]); + if (args[0]->type != tLambda) + throw TypeError(format("first argument in call to ‘filterSource’ is not a function but %1%, at %2%") % showType(*args[0]) % pos); + + FilterFromExpr filter(state, *args[0], pos); + + path = state.checkSourcePath(path); + + Path dstPath = settings.readOnlyMode + ? state.store->computeStorePathForPath(path, true, htSHA256, filter).first + : state.store->addToStore(baseNameOf(path), path, true, htSHA256, filter, state.repair); + + mkString(v, dstPath, {dstPath}); +} + + +/************************************************************* + * Sets + *************************************************************/ + + +/* Return the names of the attributes in a set as a sorted list of + strings. */ +static void prim_attrNames(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceAttrs(*args[0], pos); + + state.mkList(v, args[0]->attrs->size()); + + size_t n = 0; + for (auto & i : args[0]->attrs->lexicographicOrder()) + mkString(*(v.listElems()[n++] = state.allocValue()), i->name); +} + + +/* Return the values of the attributes in a set as a list, in the same + order as attrNames. */ +static void prim_attrValues(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceAttrs(*args[0], pos); + + state.mkList(v, args[0]->attrs->size()); + + unsigned int n = 0; + for (auto & i : *args[0]->attrs) + v.listElems()[n++] = (Value *) &i; + + std::sort(v.listElems(), v.listElems() + n, + [](Value * v1, Value * v2) { return (string) ((Attr *) v1)->name < (string) ((Attr *) v2)->name; }); + + for (unsigned int i = 0; i < n; ++i) + v.listElems()[i] = ((Attr *) v.listElems()[i])->value; +} + + +/* Dynamic version of the `.' operator. */ +void prim_getAttr(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0], pos); + state.forceAttrs(*args[1], pos); + // !!! Should we create a symbol here or just do a lookup? + Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr)); + if (i == args[1]->attrs->end()) + throw EvalError(format("attribute ‘%1%’ missing, at %2%") % attr % pos); + // !!! add to stack trace? + if (state.countCalls && i->pos) state.attrSelects[*i->pos]++; + state.forceValue(*i->value); + v = *i->value; +} + + +/* Return position information of the specified attribute. */ +void prim_unsafeGetAttrPos(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0], pos); + state.forceAttrs(*args[1], pos); + Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr)); + if (i == args[1]->attrs->end()) + mkNull(v); + else + state.mkPos(v, i->pos); +} + + +/* Dynamic version of the `?' operator. */ +static void prim_hasAttr(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0], pos); + state.forceAttrs(*args[1], pos); + mkBool(v, args[1]->attrs->find(state.symbols.create(attr)) != args[1]->attrs->end()); +} + + +/* Determine whether the argument is a set. */ +static void prim_isAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tAttrs); +} + + +static void prim_removeAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceAttrs(*args[0], pos); + state.forceList(*args[1], pos); + + /* Get the attribute names to be removed. */ + std::set<Symbol> names; + for (unsigned int i = 0; i < args[1]->listSize(); ++i) { + state.forceStringNoCtx(*args[1]->listElems()[i], pos); + names.insert(state.symbols.create(args[1]->listElems()[i]->string.s)); + } + + /* Copy all attributes not in that set. Note that we don't need + to sort v.attrs because it's a subset of an already sorted + vector. */ + state.mkAttrs(v, args[0]->attrs->size()); + for (auto & i : *args[0]->attrs) { + if (names.find(i.name) == names.end()) + v.attrs->push_back(i); + } +} + + +/* Builds a set from a list specifying (name, value) pairs. To be + precise, a list [{name = "name1"; value = value1;} ... {name = + "nameN"; value = valueN;}] is transformed to {name1 = value1; + ... nameN = valueN;}. In case of duplicate occurences of the same + name, the first takes precedence. */ +static void prim_listToAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + + state.mkAttrs(v, args[0]->listSize()); + + std::set<Symbol> seen; + + for (unsigned int i = 0; i < args[0]->listSize(); ++i) { + Value & v2(*args[0]->listElems()[i]); + state.forceAttrs(v2, pos); + + Bindings::iterator j = v2.attrs->find(state.sName); + if (j == v2.attrs->end()) + throw TypeError(format("‘name’ attribute missing in a call to ‘listToAttrs’, at %1%") % pos); + string name = state.forceStringNoCtx(*j->value, pos); + + Symbol sym = state.symbols.create(name); + if (seen.find(sym) == seen.end()) { + Bindings::iterator j2 = v2.attrs->find(state.symbols.create(state.sValue)); + if (j2 == v2.attrs->end()) + throw TypeError(format("‘value’ attribute missing in a call to ‘listToAttrs’, at %1%") % pos); + + v.attrs->push_back(Attr(sym, j2->value, j2->pos)); + seen.insert(sym); + } + } + + v.attrs->sort(); +} + + +/* Return the right-biased intersection of two sets as1 and as2, + i.e. a set that contains every attribute from as2 that is also a + member of as1. */ +static void prim_intersectAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceAttrs(*args[0], pos); + state.forceAttrs(*args[1], pos); + + state.mkAttrs(v, std::min(args[0]->attrs->size(), args[1]->attrs->size())); + + for (auto & i : *args[0]->attrs) { + Bindings::iterator j = args[1]->attrs->find(i.name); + if (j != args[1]->attrs->end()) + v.attrs->push_back(*j); + } +} + + +/* Collect each attribute named `attr' from a list of attribute sets. + Sets that don't contain the named attribute are ignored. + + Example: + catAttrs "a" [{a = 1;} {b = 0;} {a = 2;}] + => [1 2] +*/ +static void prim_catAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + Symbol attrName = state.symbols.create(state.forceStringNoCtx(*args[0], pos)); + state.forceList(*args[1], pos); + + Value * res[args[1]->listSize()]; + unsigned int found = 0; + + for (unsigned int n = 0; n < args[1]->listSize(); ++n) { + Value & v2(*args[1]->listElems()[n]); + state.forceAttrs(v2, pos); + Bindings::iterator i = v2.attrs->find(attrName); + if (i != v2.attrs->end()) + res[found++] = i->value; + } + + state.mkList(v, found); + for (unsigned int n = 0; n < found; ++n) + v.listElems()[n] = res[n]; +} + + +/* Return a set containing the names of the formal arguments expected + by the function `f'. The value of each attribute is a Boolean + denoting whether the corresponding argument has a default value. For instance, + + functionArgs ({ x, y ? 123}: ...) + => { x = false; y = true; } + + "Formal argument" here refers to the attributes pattern-matched by + the function. Plain lambdas are not included, e.g. + + functionArgs (x: ...) + => { } +*/ +static void prim_functionArgs(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + if (args[0]->type != tLambda) + throw TypeError(format("‘functionArgs’ requires a function, at %1%") % pos); + + if (!args[0]->lambda.fun->matchAttrs) { + state.mkAttrs(v, 0); + return; + } + + state.mkAttrs(v, args[0]->lambda.fun->formals->formals.size()); + for (auto & i : args[0]->lambda.fun->formals->formals) + // !!! should optimise booleans (allocate only once) + mkBool(*state.allocAttr(v, i.name), i.def); + v.attrs->sort(); +} + + +/************************************************************* + * Lists + *************************************************************/ + + +/* Determine whether the argument is a list. */ +static void prim_isList(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->isList()); +} + + +static void elemAt(EvalState & state, const Pos & pos, Value & list, int n, Value & v) +{ + state.forceList(list, pos); + if (n < 0 || (unsigned int) n >= list.listSize()) + throw Error(format("list index %1% is out of bounds, at %2%") % n % pos); + state.forceValue(*list.listElems()[n]); + v = *list.listElems()[n]; +} + + +/* Return the n-1'th element of a list. */ +static void prim_elemAt(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + elemAt(state, pos, *args[0], state.forceInt(*args[1], pos), v); +} + + +/* Return the first element of a list. */ +static void prim_head(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + elemAt(state, pos, *args[0], 0, v); +} + + +/* Return a list consisting of everything but the first element of + a list. Warning: this function takes O(n) time, so you probably + don't want to use it! */ +static void prim_tail(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + if (args[0]->listSize() == 0) + throw Error(format("‘tail’ called on an empty list, at %1%") % pos); + state.mkList(v, args[0]->listSize() - 1); + for (unsigned int n = 0; n < v.listSize(); ++n) + v.listElems()[n] = args[0]->listElems()[n + 1]; +} + + +/* Apply a function to every element of a list. */ +static void prim_map(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[1], pos); + + state.mkList(v, args[1]->listSize()); + + for (unsigned int n = 0; n < v.listSize(); ++n) + mkApp(*(v.listElems()[n] = state.allocValue()), + *args[0], *args[1]->listElems()[n]); +} + + +/* Filter a list using a predicate; that is, return a list containing + every element from the list for which the predicate function + returns true. */ +static void prim_filter(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[1], pos); + + // FIXME: putting this on the stack is risky. + Value * vs[args[1]->listSize()]; + unsigned int k = 0; + + bool same = true; + for (unsigned int n = 0; n < args[1]->listSize(); ++n) { + Value res; + state.callFunction(*args[0], *args[1]->listElems()[n], res, noPos); + if (state.forceBool(res, pos)) + vs[k++] = args[1]->listElems()[n]; + else + same = false; + } + + if (same) + v = *args[1]; + else { + state.mkList(v, k); + for (unsigned int n = 0; n < k; ++n) v.listElems()[n] = vs[n]; + } +} + + +/* Return true if a list contains a given element. */ +static void prim_elem(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + bool res = false; + state.forceList(*args[1], pos); + for (unsigned int n = 0; n < args[1]->listSize(); ++n) + if (state.eqValues(*args[0], *args[1]->listElems()[n])) { + res = true; + break; + } + mkBool(v, res); +} + + +/* Concatenate a list of lists. */ +static void prim_concatLists(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + state.concatLists(v, args[0]->listSize(), args[0]->listElems(), pos); +} + + +/* Return the length of a list. This is an O(1) time operation. */ +static void prim_length(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + mkInt(v, args[0]->listSize()); +} + + +/* Reduce a list by applying a binary operator, from left to + right. The operator is applied strictly. */ +static void prim_foldlStrict(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[2], pos); + + Value * vCur = args[1]; + + if (args[2]->listSize()) + for (unsigned int n = 0; n < args[2]->listSize(); ++n) { + Value vTmp; + state.callFunction(*args[0], *vCur, vTmp, pos); + vCur = n == args[2]->listSize() - 1 ? &v : state.allocValue(); + state.callFunction(vTmp, *args[2]->listElems()[n], *vCur, pos); + } + else + v = *vCur; + + state.forceValue(v); +} + + +static void anyOrAll(bool any, EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[1], pos); + + Value vTmp; + for (unsigned int n = 0; n < args[1]->listSize(); ++n) { + state.callFunction(*args[0], *args[1]->listElems()[n], vTmp, pos); + bool res = state.forceBool(vTmp, pos); + if (res == any) { + mkBool(v, any); + return; + } + } + + mkBool(v, !any); +} + + +static void prim_any(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + anyOrAll(true, state, pos, args, v); +} + + +static void prim_all(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + anyOrAll(false, state, pos, args, v); +} + + +static void prim_genList(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + auto len = state.forceInt(*args[1], pos); + + if (len < 0) + throw EvalError(format("cannot create list of size %1%, at %2%") % len % pos); + + state.mkList(v, len); + + for (unsigned int n = 0; n < (unsigned int) len; ++n) { + Value * arg = state.allocValue(); + mkInt(*arg, n); + mkApp(*(v.listElems()[n] = state.allocValue()), *args[0], *arg); + } +} + + +static void prim_lessThan(EvalState & state, const Pos & pos, Value * * args, Value & v); + + +static void prim_sort(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[1], pos); + + auto len = args[1]->listSize(); + state.mkList(v, len); + for (unsigned int n = 0; n < len; ++n) { + state.forceValue(*args[1]->listElems()[n]); + v.listElems()[n] = args[1]->listElems()[n]; + } + + + auto comparator = [&](Value * a, Value * b) { + /* Optimization: if the comparator is lessThan, bypass + callFunction. */ + if (args[0]->type == tPrimOp && args[0]->primOp->fun == prim_lessThan) + return CompareValues()(a, b); + + Value vTmp1, vTmp2; + state.callFunction(*args[0], *a, vTmp1, pos); + state.callFunction(vTmp1, *b, vTmp2, pos); + return state.forceBool(vTmp2, pos); + }; + + /* FIXME: std::sort can segfault if the comparator is not a strict + weak ordering. What to do? std::stable_sort() seems more + resilient, but no guarantees... */ + std::stable_sort(v.listElems(), v.listElems() + len, comparator); +} + + +static void prim_partition(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceFunction(*args[0], pos); + state.forceList(*args[1], pos); + + auto len = args[1]->listSize(); + + ValueVector right, wrong; + + for (unsigned int n = 0; n < len; ++n) { + auto vElem = args[1]->listElems()[n]; + state.forceValue(*vElem); + Value res; + state.callFunction(*args[0], *vElem, res, pos); + if (state.forceBool(res, pos)) + right.push_back(vElem); + else + wrong.push_back(vElem); + } + + state.mkAttrs(v, 2); + + Value * vRight = state.allocAttr(v, state.sRight); + state.mkList(*vRight, right.size()); + memcpy(vRight->listElems(), right.data(), sizeof(Value *) * right.size()); + + Value * vWrong = state.allocAttr(v, state.sWrong); + state.mkList(*vWrong, wrong.size()); + memcpy(vWrong->listElems(), wrong.data(), sizeof(Value *) * wrong.size()); + + v.attrs->sort(); +} + + +/************************************************************* + * Integer arithmetic + *************************************************************/ + + +static void prim_add(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + if (args[0]->type == tFloat || args[1]->type == tFloat) + mkFloat(v, state.forceFloat(*args[0], pos) + state.forceFloat(*args[1], pos)); + else + mkInt(v, state.forceInt(*args[0], pos) + state.forceInt(*args[1], pos)); +} + + +static void prim_sub(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + if (args[0]->type == tFloat || args[1]->type == tFloat) + mkFloat(v, state.forceFloat(*args[0], pos) - state.forceFloat(*args[1], pos)); + else + mkInt(v, state.forceInt(*args[0], pos) - state.forceInt(*args[1], pos)); +} + + +static void prim_mul(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + if (args[0]->type == tFloat || args[1]->type == tFloat) + mkFloat(v, state.forceFloat(*args[0], pos) * state.forceFloat(*args[1], pos)); + else + mkInt(v, state.forceInt(*args[0], pos) * state.forceInt(*args[1], pos)); +} + + +static void prim_div(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + NixFloat f2 = state.forceFloat(*args[1], pos); + if (f2 == 0) throw EvalError(format("division by zero, at %1%") % pos); + + if (args[0]->type == tFloat || args[1]->type == tFloat) { + mkFloat(v, state.forceFloat(*args[0], pos) / state.forceFloat(*args[1], pos)); + } else { + NixInt i1 = state.forceInt(*args[0], pos); + NixInt i2 = state.forceInt(*args[1], pos); + /* Avoid division overflow as it might raise SIGFPE. */ + if (i1 == std::numeric_limits<NixInt>::min() && i2 == -1) + throw EvalError(format("overflow in integer division, at %1%") % pos); + mkInt(v, i1 / i2); + } +} + + +static void prim_lessThan(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + state.forceValue(*args[1]); + CompareValues comp; + mkBool(v, comp(args[0], args[1])); +} + + +/************************************************************* + * String manipulation + *************************************************************/ + + +/* Convert the argument to a string. Paths are *not* copied to the + store, so `toString /foo/bar' yields `"/foo/bar"', not + `"/nix/store/whatever..."'. */ +static void prim_toString(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context, true, false); + mkString(v, s, context); +} + + +/* `substring start len str' returns the substring of `str' starting + at character position `min(start, stringLength str)' inclusive and + ending at `min(start + len, stringLength str)'. `start' must be + non-negative. */ +static void prim_substring(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + int start = state.forceInt(*args[0], pos); + int len = state.forceInt(*args[1], pos); + PathSet context; + string s = state.coerceToString(pos, *args[2], context); + + if (start < 0) throw EvalError(format("negative start position in ‘substring’, at %1%") % pos); + + mkString(v, (unsigned int) start >= s.size() ? "" : string(s, start, len), context); +} + + +static void prim_stringLength(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + mkInt(v, s.size()); +} + + +static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + mkString(v, s, PathSet()); +} + + +/* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a + builder without causing the derivation to be built (for instance, + in the derivation that builds NARs in nix-push, when doing + source-only deployment). This primop marks the string context so + that builtins.derivation adds the path to drv.inputSrcs rather than + drv.inputDrvs. */ +static void prim_unsafeDiscardOutputDependency(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + + PathSet context2; + for (auto & p : context) + context2.insert(p.at(0) == '=' ? "~" + string(p, 1) : p); + + mkString(v, s, context2); +} + + +/* Return the cryptographic hash of a string in base-16. */ +static void prim_hashString(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string type = state.forceStringNoCtx(*args[0], pos); + HashType ht = parseHashType(type); + if (ht == htUnknown) + throw Error(format("unknown hash type ‘%1%’, at %2%") % type % pos); + + PathSet context; // discarded + string s = state.forceString(*args[1], context, pos); + + mkString(v, printHash(hashString(ht, s)), context); +} + + +/* Match a regular expression against a string and return either + ‘null’ or a list containing substring matches. */ +static void prim_match(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + std::regex regex(state.forceStringNoCtx(*args[0], pos), std::regex::extended); + + PathSet context; + const std::string str = state.forceString(*args[1], context, pos); + + + std::smatch match; + if (!std::regex_match(str, match, regex)) { + mkNull(v); + return; + } + + // the first match is the whole string + const size_t len = match.size() - 1; + state.mkList(v, len); + for (size_t i = 0; i < len; ++i) { + if (!match[i+1].matched) + mkNull(*(v.listElems()[i] = state.allocValue())); + else + mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str()); + } +} + + +static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + + auto sep = state.forceString(*args[0], context, pos); + state.forceList(*args[1], pos); + + string res; + res.reserve((args[1]->listSize() + 32) * sep.size()); + bool first = true; + + for (unsigned int n = 0; n < args[1]->listSize(); ++n) { + if (first) first = false; else res += sep; + res += state.coerceToString(pos, *args[1]->listElems()[n], context); + } + + mkString(v, res, context); +} + + +static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + state.forceList(*args[1], pos); + if (args[0]->listSize() != args[1]->listSize()) + throw EvalError(format("‘from’ and ‘to’ arguments to ‘replaceStrings’ have different lengths, at %1%") % pos); + + vector<string> from; + from.reserve(args[0]->listSize()); + for (unsigned int n = 0; n < args[0]->listSize(); ++n) + from.push_back(state.forceString(*args[0]->listElems()[n], pos)); + + vector<std::pair<string, PathSet>> to; + to.reserve(args[1]->listSize()); + for (unsigned int n = 0; n < args[1]->listSize(); ++n) { + PathSet ctx; + auto s = state.forceString(*args[1]->listElems()[n], ctx, pos); + to.push_back(std::make_pair(std::move(s), std::move(ctx))); + } + + PathSet context; + auto s = state.forceString(*args[2], context, pos); + + string res; + for (size_t p = 0; p < s.size(); ) { + bool found = false; + auto i = from.begin(); + auto j = to.begin(); + for (; i != from.end(); ++i, ++j) + if (s.compare(p, i->size(), *i) == 0) { + found = true; + p += i->size(); + res += j->first; + for (auto& path : j->second) + context.insert(path); + j->second.clear(); + break; + } + if (!found) res += s[p++]; + } + + mkString(v, res, context); +} + + +/************************************************************* + * Versions + *************************************************************/ + + +static void prim_parseDrvName(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string name = state.forceStringNoCtx(*args[0], pos); + DrvName parsed(name); + state.mkAttrs(v, 2); + mkString(*state.allocAttr(v, state.sName), parsed.name); + mkString(*state.allocAttr(v, state.symbols.create("version")), parsed.version); + v.attrs->sort(); +} + + +static void prim_compareVersions(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + string version1 = state.forceStringNoCtx(*args[0], pos); + string version2 = state.forceStringNoCtx(*args[1], pos); + mkInt(v, compareVersions(version1, version2)); +} + + +/************************************************************* + * Networking + *************************************************************/ + + +void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v, + const string & who, bool unpack) +{ + string url; + Hash expectedHash; + string name; + + state.forceValue(*args[0]); + + if (args[0]->type == tAttrs) { + + state.forceAttrs(*args[0], pos); + + for (auto & attr : *args[0]->attrs) { + string n(attr.name); + if (n == "url") + url = state.forceStringNoCtx(*attr.value, *attr.pos); + else if (n == "sha256") + expectedHash = parseHash16or32(htSHA256, state.forceStringNoCtx(*attr.value, *attr.pos)); + else if (n == "name") + name = state.forceStringNoCtx(*attr.value, *attr.pos); + else + throw EvalError(format("unsupported argument ‘%1%’ to ‘%2%’, at %3%") % attr.name % who % attr.pos); + } + + if (url.empty()) + throw EvalError(format("‘url’ argument required, at %1%") % pos); + + } else + url = state.forceStringNoCtx(*args[0], pos); + + if (state.restricted && !expectedHash) + throw Error(format("‘%1%’ is not allowed in restricted mode") % who); + + Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash); + mkString(v, res, PathSet({res})); +} + + +static void prim_fetchurl(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + fetch(state, pos, args, v, "fetchurl", false); +} + + +static void prim_fetchTarball(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + fetch(state, pos, args, v, "fetchTarball", true); +} + + +/************************************************************* + * Primop registration + *************************************************************/ + + +RegisterPrimOp::PrimOps * RegisterPrimOp::primOps; + + +RegisterPrimOp::RegisterPrimOp(std::string name, size_t arity, PrimOpFun fun) +{ + if (!primOps) primOps = new PrimOps; + primOps->emplace_back(name, arity, fun); +} + + +void EvalState::createBaseEnv() +{ + baseEnv.up = 0; + + /* Add global constants such as `true' to the base environment. */ + Value v; + + /* `builtins' must be first! */ + mkAttrs(v, 128); + addConstant("builtins", v); + + mkBool(v, true); + addConstant("true", v); + + mkBool(v, false); + addConstant("false", v); + + mkNull(v); + addConstant("null", v); + + mkInt(v, time(0)); + addConstant("__currentTime", v); + + mkString(v, settings.thisSystem); + addConstant("__currentSystem", v); + + mkString(v, nixVersion); + addConstant("__nixVersion", v); + + mkString(v, store->storeDir); + addConstant("__storeDir", v); + + /* Language version. This should be increased every time a new + language feature gets added. It's not necessary to increase it + when primops get added, because you can just use `builtins ? + primOp' to check. */ + mkInt(v, 4); + addConstant("__langVersion", v); + + // Miscellaneous + addPrimOp("scopedImport", 2, prim_scopedImport); + Value * v2 = allocValue(); + mkAttrs(*v2, 0); + mkApp(v, *baseEnv.values[baseEnvDispl - 1], *v2); + forceValue(v); + addConstant("import", v); + if (settings.enableNativeCode) { + addPrimOp("__importNative", 2, prim_importNative); + addPrimOp("__exec", 1, prim_exec); + } + addPrimOp("__typeOf", 1, prim_typeOf); + addPrimOp("isNull", 1, prim_isNull); + addPrimOp("__isFunction", 1, prim_isFunction); + addPrimOp("__isString", 1, prim_isString); + addPrimOp("__isInt", 1, prim_isInt); + addPrimOp("__isFloat", 1, prim_isFloat); + addPrimOp("__isBool", 1, prim_isBool); + addPrimOp("__genericClosure", 1, prim_genericClosure); + addPrimOp("abort", 1, prim_abort); + addPrimOp("throw", 1, prim_throw); + addPrimOp("__addErrorContext", 2, prim_addErrorContext); + addPrimOp("__tryEval", 1, prim_tryEval); + addPrimOp("__getEnv", 1, prim_getEnv); + + // Strictness + addPrimOp("__seq", 2, prim_seq); + addPrimOp("__deepSeq", 2, prim_deepSeq); + + // Debugging + addPrimOp("__trace", 2, prim_trace); + addPrimOp("__valueSize", 1, prim_valueSize); + + // Paths + addPrimOp("__toPath", 1, prim_toPath); + addPrimOp("__storePath", 1, prim_storePath); + addPrimOp("__pathExists", 1, prim_pathExists); + addPrimOp("baseNameOf", 1, prim_baseNameOf); + addPrimOp("dirOf", 1, prim_dirOf); + addPrimOp("__readFile", 1, prim_readFile); + addPrimOp("__readDir", 1, prim_readDir); + addPrimOp("__findFile", 2, prim_findFile); + + // Creating files + addPrimOp("__toXML", 1, prim_toXML); + addPrimOp("__toJSON", 1, prim_toJSON); + addPrimOp("__fromJSON", 1, prim_fromJSON); + addPrimOp("__toFile", 2, prim_toFile); + addPrimOp("__filterSource", 2, prim_filterSource); + + // Sets + addPrimOp("__attrNames", 1, prim_attrNames); + addPrimOp("__attrValues", 1, prim_attrValues); + addPrimOp("__getAttr", 2, prim_getAttr); + addPrimOp("__unsafeGetAttrPos", 2, prim_unsafeGetAttrPos); + addPrimOp("__hasAttr", 2, prim_hasAttr); + addPrimOp("__isAttrs", 1, prim_isAttrs); + addPrimOp("removeAttrs", 2, prim_removeAttrs); + addPrimOp("__listToAttrs", 1, prim_listToAttrs); + addPrimOp("__intersectAttrs", 2, prim_intersectAttrs); + addPrimOp("__catAttrs", 2, prim_catAttrs); + addPrimOp("__functionArgs", 1, prim_functionArgs); + + // Lists + addPrimOp("__isList", 1, prim_isList); + addPrimOp("__elemAt", 2, prim_elemAt); + addPrimOp("__head", 1, prim_head); + addPrimOp("__tail", 1, prim_tail); + addPrimOp("map", 2, prim_map); + addPrimOp("__filter", 2, prim_filter); + addPrimOp("__elem", 2, prim_elem); + addPrimOp("__concatLists", 1, prim_concatLists); + addPrimOp("__length", 1, prim_length); + addPrimOp("__foldl'", 3, prim_foldlStrict); + addPrimOp("__any", 2, prim_any); + addPrimOp("__all", 2, prim_all); + addPrimOp("__genList", 2, prim_genList); + addPrimOp("__sort", 2, prim_sort); + addPrimOp("__partition", 2, prim_partition); + + // Integer arithmetic + addPrimOp("__add", 2, prim_add); + addPrimOp("__sub", 2, prim_sub); + addPrimOp("__mul", 2, prim_mul); + addPrimOp("__div", 2, prim_div); + addPrimOp("__lessThan", 2, prim_lessThan); + + // String manipulation + addPrimOp("toString", 1, prim_toString); + addPrimOp("__substring", 3, prim_substring); + addPrimOp("__stringLength", 1, prim_stringLength); + addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext); + addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency); + addPrimOp("__hashString", 2, prim_hashString); + addPrimOp("__match", 2, prim_match); + addPrimOp("__concatStringsSep", 2, prim_concatStringSep); + addPrimOp("__replaceStrings", 3, prim_replaceStrings); + + // Versions + addPrimOp("__parseDrvName", 1, prim_parseDrvName); + addPrimOp("__compareVersions", 2, prim_compareVersions); + + // Derivations + addPrimOp("derivationStrict", 1, prim_derivationStrict); + addPrimOp("placeholder", 1, prim_placeholder); + + // Networking + addPrimOp("__fetchurl", 1, prim_fetchurl); + addPrimOp("fetchTarball", 1, prim_fetchTarball); + + /* Add a wrapper around the derivation primop that computes the + `drvPath' and `outPath' attributes lazily. */ + string path = settings.nixDataDir + "/nix/corepkgs/derivation.nix"; + sDerivationNix = symbols.create(path); + evalFile(path, v); + addConstant("derivation", v); + + /* Add a value containing the current Nix expression search path. */ + mkList(v, searchPath.size()); + int n = 0; + for (auto & i : searchPath) { + v2 = v.listElems()[n++] = allocValue(); + mkAttrs(*v2, 2); + mkString(*allocAttr(*v2, symbols.create("path")), i.second); + mkString(*allocAttr(*v2, symbols.create("prefix")), i.first); + v2->attrs->sort(); + } + addConstant("__nixPath", v); + + if (RegisterPrimOp::primOps) + for (auto & primOp : *RegisterPrimOp::primOps) + addPrimOp(std::get<0>(primOp), std::get<1>(primOp), std::get<2>(primOp)); + + /* Now that we've added all primops, sort the `builtins' set, + because attribute lookups expect it to be sorted. */ + baseEnv.values[0]->attrs->sort(); +} + + +} |