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#include "command.hh"
#include "common-args.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 : InstallablesCommand
{
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 outPaths = toStorePaths(store, Build);
auto store2 = store.dynamic_pointer_cast<LocalStore>();
if (store2 && store->storeDir != store2->realStoreDir) {
#if __linux__
uid_t uid = getuid();
uid_t gid = getgid();
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);
writeFile("/proc/self/setgroups", "deny");
writeFile("/proc/self/uid_map", (format("%d %d %d") % uid % uid % 1).str());
writeFile("/proc/self/gid_map", (format("%d %d %d") % gid % gid % 1).str());
#else
throw Error(format("mounting the Nix store on '%s' is not supported on this platform") % store->storeDir);
#endif
}
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>());
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