Merge commit 'aa99005004bccc9be506a2a2f162f78bad4bcb41' into ca-drv-exotic

8 files changed, 94 insertions, 75 deletions

diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 2021d0023..596034c0f 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -199,10 +199,10 @@ void DerivationGoal::haveDerivation()
     parsedDrv = std::make_unique<ParsedDerivation>(drvPath, *drv);
 
     if (!drv->type().hasKnownOutputPaths())
-        settings.requireExperimentalFeature(Xp::CaDerivations);
+        experimentalFeatureSettings.require(Xp::CaDerivations);
 
     if (!drv->type().isPure()) {
-        settings.requireExperimentalFeature(Xp::ImpureDerivations);
+        experimentalFeatureSettings.require(Xp::ImpureDerivations);
 
         for (auto & [outputName, output] : drv->outputs) {
             auto randomPath = StorePath::random(outputPathName(drv->name, outputName));
@@ -336,7 +336,7 @@ void DerivationGoal::gaveUpOnSubstitution()
         for (auto & i : dynamic_cast<Derivation *>(drv.get())->inputDrvs) {
             /* Ensure that pure, non-fixed-output derivations don't
                depend on impure derivations. */
-            if (settings.isExperimentalFeatureEnabled(Xp::ImpureDerivations) && drv->type().isPure() && !drv->type().isFixed()) {
+            if (experimentalFeatureSettings.isEnabled(Xp::ImpureDerivations) && drv->type().isPure() && !drv->type().isFixed()) {
                 auto inputDrv = worker.evalStore.readDerivation(i.first);
                 if (!inputDrv.type().isPure())
                     throw Error("pure derivation '%s' depends on impure derivation '%s'",
@@ -477,7 +477,7 @@ void DerivationGoal::inputsRealised()
                     ca.fixed
                     /* Can optionally resolve if fixed, which is good
                        for avoiding unnecessary rebuilds. */
-                    ? settings.isExperimentalFeatureEnabled(Xp::CaDerivations)
+                    ? experimentalFeatureSettings.isEnabled(Xp::CaDerivations)
                     /* Must resolve if floating and there are any inputs
                        drvs. */
                     : true);
@@ -488,7 +488,7 @@ void DerivationGoal::inputsRealised()
         }, drvType.raw());
 
         if (resolveDrv && !fullDrv.inputDrvs.empty()) {
-            settings.requireExperimentalFeature(Xp::CaDerivations);
+            experimentalFeatureSettings.require(Xp::CaDerivations);
 
             /* We are be able to resolve this derivation based on the
                now-known results of dependencies. If so, we become a
@@ -732,7 +732,7 @@ void replaceValidPath(const Path & storePath, const Path & tmpPath)
        tmpPath (the replacement), so we have to move it out of the
        way first.  We'd better not be interrupted here, because if
        we're repairing (say) Glibc, we end up with a broken system. */
-    Path oldPath = (format("%1%.old-%2%-%3%") % storePath % getpid() % random()).str();
+    Path oldPath = fmt("%1%.old-%2%-%3%", storePath, getpid(), random());
     if (pathExists(storePath))
         movePath(storePath, oldPath);
 
@@ -1352,7 +1352,7 @@ std::pair<bool, DrvOutputs> DerivationGoal::checkPathValidity()
             };
         }
         auto drvOutput = DrvOutput{info.outputHash, i.first};
-        if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations)) {
+        if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)) {
             if (auto real = worker.store.queryRealisation(drvOutput)) {
                 info.known = {
                     .path = real->outPath,
diff --git a/src/libstore/build/drv-output-substitution-goal.cc b/src/libstore/build/drv-output-substitution-goal.cc
index b7f7b5ab1..b30957c84 100644
--- a/src/libstore/build/drv-output-substitution-goal.cc
+++ b/src/libstore/build/drv-output-substitution-goal.cc
@@ -61,20 +61,25 @@ void DrvOutputSubstitutionGoal::tryNext()
 
     // FIXME: Make async
     // outputInfo = sub->queryRealisation(id);
-    outPipe.create();
-    promise = decltype(promise)();
+
+    /* The callback of the curl download below can outlive `this` (if
+       some other error occurs), so it must not touch `this`. So put
+       the shared state in a separate refcounted object. */
+    downloadState = std::make_shared<DownloadState>();
+    downloadState->outPipe.create();
 
     sub->queryRealisation(
-        id, { [&](std::future<std::shared_ptr<const Realisation>> res) {
+        id,
+        { [downloadState(downloadState)](std::future<std::shared_ptr<const Realisation>> res) {
             try {
-                Finally updateStats([this]() { outPipe.writeSide.close(); });
-                promise.set_value(res.get());
+                Finally updateStats([&]() { downloadState->outPipe.writeSide.close(); });
+                downloadState->promise.set_value(res.get());
             } catch (...) {
-                promise.set_exception(std::current_exception());
+                downloadState->promise.set_exception(std::current_exception());
             }
         } });
 
-    worker.childStarted(shared_from_this(), {outPipe.readSide.get()}, true, false);
+    worker.childStarted(shared_from_this(), {downloadState->outPipe.readSide.get()}, true, false);
 
     state = &DrvOutputSubstitutionGoal::realisationFetched;
 }
@@ -84,7 +89,7 @@ void DrvOutputSubstitutionGoal::realisationFetched()
     worker.childTerminated(this);
 
     try {
-        outputInfo = promise.get_future().get();
+        outputInfo = downloadState->promise.get_future().get();
     } catch (std::exception & e) {
         printError(e.what());
         substituterFailed = true;
@@ -155,7 +160,7 @@ void DrvOutputSubstitutionGoal::work()
 
 void DrvOutputSubstitutionGoal::handleEOF(int fd)
 {
-    if (fd == outPipe.readSide.get()) worker.wakeUp(shared_from_this());
+    if (fd == downloadState->outPipe.readSide.get()) worker.wakeUp(shared_from_this());
 }
 
 
diff --git a/src/libstore/build/drv-output-substitution-goal.hh b/src/libstore/build/drv-output-substitution-goal.hh
index 948dbda8f..e4b044790 100644
--- a/src/libstore/build/drv-output-substitution-goal.hh
+++ b/src/libstore/build/drv-output-substitution-goal.hh
@@ -16,7 +16,7 @@ class Worker;
 // 2. Substitute the corresponding output path
 // 3. Register the output info
 class DrvOutputSubstitutionGoal : public Goal {
-private:
+
     // The drv output we're trying to substitue
     DrvOutput id;
 
@@ -30,9 +30,13 @@ private:
     /* The current substituter. */
     std::shared_ptr<Store> sub;
 
-    Pipe outPipe;
-    std::thread thr;
-    std::promise<std::shared_ptr<const Realisation>> promise;
+    struct DownloadState
+    {
+        Pipe outPipe;
+        std::promise<std::shared_ptr<const Realisation>> promise;
+    };
+
+    std::shared_ptr<DownloadState> downloadState;
 
     /* Whether a substituter failed. */
     bool substituterFailed = false;
diff --git a/src/libstore/build/goal.cc b/src/libstore/build/goal.cc
index 58e805f55..d59b94797 100644
--- a/src/libstore/build/goal.cc
+++ b/src/libstore/build/goal.cc
@@ -78,9 +78,9 @@ void Goal::amDone(ExitCode result, std::optional<Error> ex)
 }
 
 
-void Goal::trace(const FormatOrString & fs)
+void Goal::trace(std::string_view s)
 {
-    debug("%1%: %2%", name, fs.s);
+    debug("%1%: %2%", name, s);
 }
 
 }
diff --git a/src/libstore/build/goal.hh b/src/libstore/build/goal.hh
index 35121c5d9..776eb86bc 100644
--- a/src/libstore/build/goal.hh
+++ b/src/libstore/build/goal.hh
@@ -88,7 +88,7 @@ struct Goal : public std::enable_shared_from_this<Goal>
         abort();
     }
 
-    void trace(const FormatOrString & fs);
+    void trace(std::string_view s);
 
     std::string getName()
     {
diff --git a/src/libstore/build/hook-instance.cc b/src/libstore/build/hook-instance.cc
index cb58a1f02..075ad554f 100644
--- a/src/libstore/build/hook-instance.cc
+++ b/src/libstore/build/hook-instance.cc
@@ -35,7 +35,10 @@ HookInstance::HookInstance()
     /* Fork the hook. */
     pid = startProcess([&]() {
 
-        commonChildInit(fromHook);
+        if (dup2(fromHook.writeSide.get(), STDERR_FILENO) == -1)
+            throw SysError("cannot pipe standard error into log file");
+
+        commonChildInit();
 
         if (chdir("/") == -1) throw SysError("changing into /");
 
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 85e9e16ff..449ff13e8 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -292,7 +292,7 @@ void LocalDerivationGoal::closeReadPipes()
     if (hook) {
         DerivationGoal::closeReadPipes();
     } else
-        builderOut.readSide = -1;
+        builderOut.close();
 }
 
 
@@ -413,7 +413,7 @@ void LocalDerivationGoal::startBuilder()
         )
     {
         #if __linux__
-        settings.requireExperimentalFeature(Xp::Cgroups);
+        experimentalFeatureSettings.require(Xp::Cgroups);
 
         auto cgroupFS = getCgroupFS();
         if (!cgroupFS)
@@ -650,7 +650,7 @@ void LocalDerivationGoal::startBuilder()
         /* Clean up the chroot directory automatically. */
         autoDelChroot = std::make_shared<AutoDelete>(chrootRootDir);
 
-        printMsg(lvlChatty, format("setting up chroot environment in '%1%'") % chrootRootDir);
+        printMsg(lvlChatty, "setting up chroot environment in '%1%'", chrootRootDir);
 
         // FIXME: make this 0700
         if (mkdir(chrootRootDir.c_str(), buildUser && buildUser->getUIDCount() != 1 ? 0755 : 0750) == -1)
@@ -753,8 +753,7 @@ void LocalDerivationGoal::startBuilder()
         throw Error("home directory '%1%' exists; please remove it to assure purity of builds without sandboxing", homeDir);
 
     if (useChroot && settings.preBuildHook != "" && dynamic_cast<Derivation *>(drv.get())) {
-        printMsg(lvlChatty, format("executing pre-build hook '%1%'")
-            % settings.preBuildHook);
+        printMsg(lvlChatty, "executing pre-build hook '%1%'", settings.preBuildHook);
         auto args = useChroot ? Strings({worker.store.printStorePath(drvPath), chrootRootDir}) :
             Strings({ worker.store.printStorePath(drvPath) });
         enum BuildHookState {
@@ -803,15 +802,13 @@ void LocalDerivationGoal::startBuilder()
     /* Create the log file. */
     Path logFile = openLogFile();
 
-    /* Create a pipe to get the output of the builder. */
-    //builderOut.create();
-
-    builderOut.readSide = posix_openpt(O_RDWR | O_NOCTTY);
-    if (!builderOut.readSide)
+    /* Create a pseudoterminal to get the output of the builder. */
+    builderOut = posix_openpt(O_RDWR | O_NOCTTY);
+    if (!builderOut)
         throw SysError("opening pseudoterminal master");
 
     // FIXME: not thread-safe, use ptsname_r
-    std::string slaveName(ptsname(builderOut.readSide.get()));
+    std::string slaveName = ptsname(builderOut.get());
 
     if (buildUser) {
         if (chmod(slaveName.c_str(), 0600))
@@ -822,34 +819,34 @@ void LocalDerivationGoal::startBuilder()
     }
 #if __APPLE__
     else {
-        if (grantpt(builderOut.readSide.get()))
+        if (grantpt(builderOut.get()))
             throw SysError("granting access to pseudoterminal slave");
     }
 #endif
 
-    #if 0
-    // Mount the pt in the sandbox so that the "tty" command works.
-    // FIXME: this doesn't work with the new devpts in the sandbox.
-    if (useChroot)
-        dirsInChroot[slaveName] = {slaveName, false};
-    #endif
-
-    if (unlockpt(builderOut.readSide.get()))
+    if (unlockpt(builderOut.get()))
         throw SysError("unlocking pseudoterminal");
 
-    builderOut.writeSide = open(slaveName.c_str(), O_RDWR | O_NOCTTY);
-    if (!builderOut.writeSide)
-        throw SysError("opening pseudoterminal slave");
+    /* Open the slave side of the pseudoterminal and use it as stderr. */
+    auto openSlave = [&]()
+    {
+        AutoCloseFD builderOut = open(slaveName.c_str(), O_RDWR | O_NOCTTY);
+        if (!builderOut)
+            throw SysError("opening pseudoterminal slave");
 
-    // Put the pt into raw mode to prevent \n -> \r\n translation.
-    struct termios term;
-    if (tcgetattr(builderOut.writeSide.get(), &term))
-        throw SysError("getting pseudoterminal attributes");
+        // Put the pt into raw mode to prevent \n -> \r\n translation.
+        struct termios term;
+        if (tcgetattr(builderOut.get(), &term))
+            throw SysError("getting pseudoterminal attributes");
 
-    cfmakeraw(&term);
+        cfmakeraw(&term);
 
-    if (tcsetattr(builderOut.writeSide.get(), TCSANOW, &term))
-        throw SysError("putting pseudoterminal into raw mode");
+        if (tcsetattr(builderOut.get(), TCSANOW, &term))
+            throw SysError("putting pseudoterminal into raw mode");
+
+        if (dup2(builderOut.get(), STDERR_FILENO) == -1)
+            throw SysError("cannot pipe standard error into log file");
+    };
 
     buildResult.startTime = time(0);
 
@@ -898,7 +895,16 @@ void LocalDerivationGoal::startBuilder()
 
         usingUserNamespace = userNamespacesSupported();
 
+        Pipe sendPid;
+        sendPid.create();
+
         Pid helper = startProcess([&]() {
+            sendPid.readSide.close();
+
+            /* We need to open the slave early, before
+               CLONE_NEWUSER. Otherwise we get EPERM when running as
+               root. */
+            openSlave();
 
             /* Drop additional groups here because we can't do it
                after we've created the new user namespace.  FIXME:
@@ -920,11 +926,12 @@ void LocalDerivationGoal::startBuilder()
 
             pid_t child = startProcess([&]() { runChild(); }, options);
 
-            writeFull(builderOut.writeSide.get(),
-                fmt("%d %d\n", usingUserNamespace, child));
+            writeFull(sendPid.writeSide.get(), fmt("%d\n", child));
             _exit(0);
         });
 
+        sendPid.writeSide.close();
+
         if (helper.wait() != 0)
             throw Error("unable to start build process");
 
@@ -936,10 +943,9 @@ void LocalDerivationGoal::startBuilder()
             userNamespaceSync.writeSide = -1;
         });
 
-        auto ss = tokenizeString<std::vector<std::string>>(readLine(builderOut.readSide.get()));
-        assert(ss.size() == 2);
-        usingUserNamespace = ss[0] == "1";
-        pid = string2Int<pid_t>(ss[1]).value();
+        auto ss = tokenizeString<std::vector<std::string>>(readLine(sendPid.readSide.get()));
+        assert(ss.size() == 1);
+        pid = string2Int<pid_t>(ss[0]).value();
 
         if (usingUserNamespace) {
             /* Set the UID/GID mapping of the builder's user namespace
@@ -994,21 +1000,21 @@ void LocalDerivationGoal::startBuilder()
 #endif
     {
         pid = startProcess([&]() {
+            openSlave();
             runChild();
         });
     }
 
     /* parent */
     pid.setSeparatePG(true);
-    builderOut.writeSide = -1;
-    worker.childStarted(shared_from_this(), {builderOut.readSide.get()}, true, true);
+    worker.childStarted(shared_from_this(), {builderOut.get()}, true, true);
 
     /* Check if setting up the build environment failed. */
     std::vector<std::string> msgs;
     while (true) {
         std::string msg = [&]() {
             try {
-                return readLine(builderOut.readSide.get());
+                return readLine(builderOut.get());
             } catch (Error & e) {
                 auto status = pid.wait();
                 e.addTrace({}, "while waiting for the build environment for '%s' to initialize (%s, previous messages: %s)",
@@ -1020,7 +1026,7 @@ void LocalDerivationGoal::startBuilder()
         }();
         if (msg.substr(0, 1) == "\2") break;
         if (msg.substr(0, 1) == "\1") {
-            FdSource source(builderOut.readSide.get());
+            FdSource source(builderOut.get());
             auto ex = readError(source);
             ex.addTrace({}, "while setting up the build environment");
             throw ex;
@@ -1104,7 +1110,7 @@ void LocalDerivationGoal::initEnv()
     env["NIX_STORE"] = worker.store.storeDir;
 
     /* The maximum number of cores to utilize for parallel building. */
-    env["NIX_BUILD_CORES"] = (format("%d") % settings.buildCores).str();
+    env["NIX_BUILD_CORES"] = fmt("%d", settings.buildCores);
 
     initTmpDir();
 
@@ -1155,10 +1161,10 @@ void LocalDerivationGoal::writeStructuredAttrs()
 
         writeFile(tmpDir + "/.attrs.sh", rewriteStrings(jsonSh, inputRewrites));
         chownToBuilder(tmpDir + "/.attrs.sh");
-        env["NIX_ATTRS_SH_FILE"] = tmpDir + "/.attrs.sh";
+        env["NIX_ATTRS_SH_FILE"] = tmpDirInSandbox + "/.attrs.sh";
         writeFile(tmpDir + "/.attrs.json", rewriteStrings(json.dump(), inputRewrites));
         chownToBuilder(tmpDir + "/.attrs.json");
-        env["NIX_ATTRS_JSON_FILE"] = tmpDir + "/.attrs.json";
+        env["NIX_ATTRS_JSON_FILE"] = tmpDirInSandbox + "/.attrs.json";
     }
 }
 
@@ -1414,7 +1420,7 @@ struct RestrictedStore : public virtual RestrictedStoreConfig, public virtual Lo
 
 void LocalDerivationGoal::startDaemon()
 {
-    settings.requireExperimentalFeature(Xp::RecursiveNix);
+    experimentalFeatureSettings.require(Xp::RecursiveNix);
 
     Store::Params params;
     params["path-info-cache-size"] = "0";
@@ -1650,7 +1656,7 @@ void LocalDerivationGoal::runChild()
 
     try { /* child */
 
-        commonChildInit(builderOut);
+        commonChildInit();
 
         try {
             setupSeccomp();
@@ -2063,7 +2069,7 @@ void LocalDerivationGoal::runChild()
 
             /* The tmpDir in scope points at the temporary build directory for our derivation. Some packages try different mechanisms
                to find temporary directories, so we want to open up a broader place for them to dump their files, if needed. */
-            Path globalTmpDir = canonPath(getEnv("TMPDIR").value_or("/tmp"), true);
+            Path globalTmpDir = canonPath(getEnvNonEmpty("TMPDIR").value_or("/tmp"), true);
 
             /* They don't like trailing slashes on subpath directives */
             if (globalTmpDir.back() == '/') globalTmpDir.pop_back();
@@ -2274,7 +2280,7 @@ DrvOutputs LocalDerivationGoal::registerOutputs()
         bool discardReferences = false;
         if (auto structuredAttrs = parsedDrv->getStructuredAttrs()) {
             if (auto udr = get(*structuredAttrs, "unsafeDiscardReferences")) {
-                settings.requireExperimentalFeature(Xp::DiscardReferences);
+                experimentalFeatureSettings.require(Xp::DiscardReferences);
                 if (auto output = get(*udr, outputName)) {
                     if (!output->is_boolean())
                         throw Error("attribute 'unsafeDiscardReferences.\"%s\"' of derivation '%s' must be a Boolean", outputName, drvPath.to_string());
@@ -2698,7 +2704,7 @@ DrvOutputs LocalDerivationGoal::registerOutputs()
             },
             .outPath = newInfo.path
         };
-        if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations)
+        if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)
             && drv->type().isPure())
         {
             signRealisation(thisRealisation);
@@ -2896,7 +2902,7 @@ void LocalDerivationGoal::deleteTmpDir(bool force)
 bool LocalDerivationGoal::isReadDesc(int fd)
 {
     return (hook && DerivationGoal::isReadDesc(fd)) ||
-        (!hook && fd == builderOut.readSide.get());
+        (!hook && fd == builderOut.get());
 }
 
 
diff --git a/src/libstore/build/local-derivation-goal.hh b/src/libstore/build/local-derivation-goal.hh
index 34c4e9187..c9ecc8828 100644
--- a/src/libstore/build/local-derivation-goal.hh
+++ b/src/libstore/build/local-derivation-goal.hh
@@ -24,8 +24,9 @@ struct LocalDerivationGoal : public DerivationGoal
     /* The path of the temporary directory in the sandbox. */
     Path tmpDirInSandbox;
 
-    /* Pipe for the builder's standard output/error. */
-    Pipe builderOut;
+    /* Master side of the pseudoterminal used for the builder's
+       standard output/error. */
+    AutoCloseFD builderOut;
 
     /* Pipe for synchronising updates to the builder namespaces. */
     Pipe userNamespaceSync;