diff options
Diffstat (limited to 'src/libstore/build.cc')
| -rw-r--r-- | src/libstore/build.cc | 47 |
1 files changed, 35 insertions, 12 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index e64bd3fef587..ac5ca7bc3a36 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -1768,12 +1768,20 @@ void DerivationGoal::startBuilder() functions like fetchurl (which needs a proper /etc/resolv.conf) work properly. Purity checking for fixed-output derivations is somewhat pointless anyway. */ - useChroot = settings.useChroot; - - if (fixedOutput) useChroot = false; - - /* Hack to allow derivations to disable chroot builds. */ - if (get(drv.env, "__noChroot") == "1") useChroot = false; + { + string x = settings.get("build-use-chroot", string("false")); + if (x != "true" && x != "false" && x != "relaxed") + throw Error("option ‘build-use-chroot’ must be set to one of ‘true’, ‘false’ or ‘relaxed’"); + if (x == "true") { + if (get(drv.env, "__noChroot") == "1") + throw Error(format("derivation ‘%1%’ has ‘__noChroot’ set, but that's not allowed when ‘build-use-chroot’ is ‘true’") % drvPath); + useChroot = true; + } + else if (x == "false") + useChroot = false; + else if (x == "relaxed") + useChroot = !fixedOutput && get(drv.env, "__noChroot") != "1"; + } if (useChroot) { /* Allow a user-configurable set of directories from the @@ -1856,7 +1864,8 @@ void DerivationGoal::startBuilder() % (buildUser.enabled() ? buildUser.getGID() : getgid())).str()); /* Create /etc/hosts with localhost entry. */ - writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n"); + if (!fixedOutput) + writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n"); /* Make the closure of the inputs available in the chroot, rather than the whole Nix store. This prevents any access @@ -1964,7 +1973,9 @@ void DerivationGoal::startBuilder() - The private network namespace ensures that the builder cannot talk to the outside world (or vice versa). It - only has a private loopback interface. + only has a private loopback interface. (Fixed-output + derivations are not run in a private network namespace + to allow functions like fetchurl to work.) - The IPC namespace prevents the builder from communicating with outside processes using SysV IPC mechanisms (shared @@ -1983,8 +1994,9 @@ void DerivationGoal::startBuilder() */ Pid helper = startProcess([&]() { char stack[32 * 1024]; - pid_t child = clone(childEntry, stack + sizeof(stack) - 8, - CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWNET | CLONE_NEWIPC | CLONE_NEWUTS | CLONE_PARENT | SIGCHLD, this); + int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | CLONE_NEWUTS | CLONE_PARENT | SIGCHLD; + if (!fixedOutput) flags |= CLONE_NEWNET; + pid_t child = clone(childEntry, stack + sizeof(stack) - 8, flags, this); if (child == -1) { if (errno == EINVAL) throw SysError("cloning builder process (Linux chroot builds require 3.13 or later)"); @@ -2081,10 +2093,10 @@ void DerivationGoal::runChild() /* Set up a nearly empty /dev, unless the user asked to bind-mount the host /dev. */ + Strings ss; if (dirsInChroot.find("/dev") == dirsInChroot.end()) { createDirs(chrootRootDir + "/dev/shm"); createDirs(chrootRootDir + "/dev/pts"); - Strings ss; ss.push_back("/dev/full"); #ifdef __linux__ if (pathExists("/dev/kvm")) @@ -2095,13 +2107,24 @@ void DerivationGoal::runChild() ss.push_back("/dev/tty"); ss.push_back("/dev/urandom"); ss.push_back("/dev/zero"); - foreach (Strings::iterator, i, ss) dirsInChroot[*i] = *i; createSymlink("/proc/self/fd", chrootRootDir + "/dev/fd"); createSymlink("/proc/self/fd/0", chrootRootDir + "/dev/stdin"); createSymlink("/proc/self/fd/1", chrootRootDir + "/dev/stdout"); createSymlink("/proc/self/fd/2", chrootRootDir + "/dev/stderr"); } + /* Fixed-output derivations typically need to access the + network, so give them access to /etc/resolv.conf and so + on. */ + if (fixedOutput) { + ss.push_back("/etc/resolv.conf"); + ss.push_back("/etc/nsswitch.conf"); + ss.push_back("/etc/services"); + ss.push_back("/etc/hosts"); + } + + for (auto & i : ss) dirsInChroot[i] = i; + /* Bind-mount all the directories from the "host" filesystem that we want in the chroot environment. */ |