lix/src/nix/run.cc

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#include "command.hh"
#include "common-args.hh"
#include "installables.hh"
#include "shared.hh"
#include "store-api.hh"
#include "derivations.hh"
#include "local-store.hh"
#include "finally.hh"
#if __linux__
#include <sys/mount.h>
#endif
using namespace nix;
struct CmdRun : StoreCommand, MixInstallables
{
CmdRun()
{
}
std::string name() override
{
return "run";
}
std::string description() override
{
return "run a shell in which the specified packages are available";
}
void run(ref<Store> store) override
{
auto elems = evalInstallables(store);
PathSet pathsToBuild;
for (auto & elem : elems) {
if (elem.isDrv)
pathsToBuild.insert(elem.drvPath);
else
pathsToBuild.insert(elem.outPaths.begin(), elem.outPaths.end());
}
printMissing(store, pathsToBuild);
store->buildPaths(pathsToBuild);
auto store2 = store.dynamic_pointer_cast<LocalStore>();
if (store2 && store->storeDir != store2->realStoreDir) {
#if __linux__
if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == -1)
throw SysError("setting up a private mount namespace");
/* Bind-mount realStoreDir on /nix/store. If the latter
mount point doesn't already exists, we have to create a
chroot environment containing the mount point and bind
mounts for the children of /. Would be nice if we could
use overlayfs here, but that doesn't work in a user
namespace yet (Ubuntu has a patch for this:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1478578). */
if (!pathExists(store->storeDir)) {
// FIXME: Use overlayfs?
Path tmpDir = createTempDir();
createDirs(tmpDir + store->storeDir);
if (mount(store2->realStoreDir.c_str(), (tmpDir + store->storeDir).c_str(), "", MS_BIND, 0) == -1)
throw SysError(format("mounting %s on %s") % store2->realStoreDir % store->storeDir);
for (auto entry : readDirectory("/")) {
Path dst = tmpDir + "/" + entry.name;
if (pathExists(dst)) continue;
if (mkdir(dst.c_str(), 0700) == -1)
throw SysError(format("creating directory %s") % dst);
if (mount(("/" + entry.name).c_str(), dst.c_str(), "", MS_BIND | MS_REC, 0) == -1)
throw SysError(format("mounting %s on %s") % ("/" + entry.name) % dst);
}
char * cwd = getcwd(0, 0);
if (!cwd) throw SysError("getting current directory");
Finally freeCwd([&]() { free(cwd); });
if (chroot(tmpDir.c_str()) == -1)
throw SysError(format("chrooting into %s") % tmpDir);
if (chdir(cwd) == -1)
throw SysError(format("chdir to %s in chroot") % cwd);
} else
if (mount(store2->realStoreDir.c_str(), store->storeDir.c_str(), "", MS_BIND, 0) == -1)
throw SysError(format("mounting %s on %s") % store2->realStoreDir % store->storeDir);
#else
throw Error(format("mounting the Nix store on %s is not supported on this platform") % store->storeDir);
#endif
}
PathSet outPaths;
for (auto & path : pathsToBuild)
if (isDerivation(path)) {
Derivation drv = store->derivationFromPath(path);
for (auto & output : drv.outputs)
outPaths.insert(output.second.path);
} else
outPaths.insert(path);
auto unixPath = tokenizeString<Strings>(getEnv("PATH"), ":");
for (auto & path : outPaths)
if (pathExists(path + "/bin"))
unixPath.push_front(path + "/bin");
setenv("PATH", concatStringsSep(":", unixPath).c_str(), 1);
if (execlp("bash", "bash", nullptr) == -1)
throw SysError("unable to exec bash");
}
};
static RegisterCommand r1(make_ref<CmdRun>());