234 lines
7.5 KiB
C++
234 lines
7.5 KiB
C++
#include "command.hh"
|
|
#include "common-args.hh"
|
|
#include "shared.hh"
|
|
#include "store-api.hh"
|
|
#include "derivations.hh"
|
|
#include "local-store.hh"
|
|
#include "finally.hh"
|
|
#include "fs-accessor.hh"
|
|
#include "progress-bar.hh"
|
|
|
|
#if __linux__
|
|
#include <sys/mount.h>
|
|
#endif
|
|
|
|
using namespace nix;
|
|
|
|
std::string chrootHelperName = "__run_in_chroot";
|
|
|
|
extern char * * environ;
|
|
|
|
struct CmdRun : InstallablesCommand
|
|
{
|
|
std::vector<std::string> command = { "bash" };
|
|
StringSet keep, unset;
|
|
bool ignoreEnvironment = false;
|
|
|
|
CmdRun()
|
|
{
|
|
mkFlag()
|
|
.longName("command")
|
|
.shortName('c')
|
|
.description("command and arguments to be executed; defaults to 'bash'")
|
|
.arity(ArityAny)
|
|
.labels({"command", "args"})
|
|
.handler([&](std::vector<std::string> ss) {
|
|
if (ss.empty()) throw UsageError("--command requires at least one argument");
|
|
command = ss;
|
|
});
|
|
|
|
mkFlag()
|
|
.longName("ignore-environment")
|
|
.shortName('i')
|
|
.description("clear the entire environment (except those specified with --keep)")
|
|
.set(&ignoreEnvironment, true);
|
|
|
|
mkFlag()
|
|
.longName("keep")
|
|
.shortName('k')
|
|
.description("keep specified environment variable")
|
|
.arity(1)
|
|
.labels({"name"})
|
|
.handler([&](std::vector<std::string> ss) { keep.insert(ss.front()); });
|
|
|
|
mkFlag()
|
|
.longName("unset")
|
|
.shortName('u')
|
|
.description("unset specified environment variable")
|
|
.arity(1)
|
|
.labels({"name"})
|
|
.handler([&](std::vector<std::string> ss) { unset.insert(ss.front()); });
|
|
}
|
|
|
|
std::string name() override
|
|
{
|
|
return "run";
|
|
}
|
|
|
|
std::string description() override
|
|
{
|
|
return "run a shell in which the specified packages are available";
|
|
}
|
|
|
|
Examples examples() override
|
|
{
|
|
return {
|
|
Example{
|
|
"To start a shell providing GNU Hello from NixOS 17.03:",
|
|
"nix run -f channel:nixos-17.03 hello"
|
|
},
|
|
Example{
|
|
"To start a shell providing youtube-dl from your 'nixpkgs' channel:",
|
|
"nix run nixpkgs.youtube-dl"
|
|
},
|
|
Example{
|
|
"To run GNU Hello:",
|
|
"nix run nixpkgs.hello -c hello --greeting 'Hi everybody!'"
|
|
},
|
|
};
|
|
}
|
|
|
|
void run(ref<Store> store) override
|
|
{
|
|
auto outPaths = toStorePaths(store, Build, installables);
|
|
|
|
auto accessor = store->getFSAccessor();
|
|
|
|
if (ignoreEnvironment) {
|
|
|
|
if (!unset.empty())
|
|
throw UsageError("--unset does not make sense with --ignore-environment");
|
|
|
|
std::map<std::string, std::string> kept;
|
|
for (auto & var : keep) {
|
|
auto s = getenv(var.c_str());
|
|
if (s) kept[var] = s;
|
|
}
|
|
|
|
environ = nullptr;
|
|
|
|
for (auto & var : kept)
|
|
setenv(var.first.c_str(), var.second.c_str(), 1);
|
|
|
|
} else {
|
|
|
|
if (!keep.empty())
|
|
throw UsageError("--keep does not make sense without --ignore-environment");
|
|
|
|
for (auto & var : unset)
|
|
unsetenv(var.c_str());
|
|
}
|
|
|
|
auto unixPath = tokenizeString<Strings>(getEnv("PATH"), ":");
|
|
for (auto & path : outPaths)
|
|
if (accessor->stat(path + "/bin").type != FSAccessor::tMissing)
|
|
unixPath.push_front(path + "/bin");
|
|
setenv("PATH", concatStringsSep(":", unixPath).c_str(), 1);
|
|
|
|
std::string cmd = *command.begin();
|
|
Strings args;
|
|
for (auto & arg : command) args.push_back(arg);
|
|
|
|
stopProgressBar();
|
|
|
|
restoreSignals();
|
|
|
|
/* If this is a diverted store (i.e. its "logical" location
|
|
(typically /nix/store) differs from its "physical" location
|
|
(e.g. /home/eelco/nix/store), then run the command in a
|
|
chroot. For non-root users, this requires running it in new
|
|
mount and user namespaces. Unfortunately,
|
|
unshare(CLONE_NEWUSER) doesn't work in a multithreaded
|
|
program (which "nix" is), so we exec() a single-threaded
|
|
helper program (chrootHelper() below) to do the work. */
|
|
auto store2 = store.dynamic_pointer_cast<LocalStore>();
|
|
|
|
if (store2 && store->storeDir != store2->realStoreDir) {
|
|
Strings helperArgs = { chrootHelperName, store->storeDir, store2->realStoreDir, cmd };
|
|
for (auto & arg : args) helperArgs.push_back(arg);
|
|
|
|
execv(readLink("/proc/self/exe").c_str(), stringsToCharPtrs(helperArgs).data());
|
|
|
|
throw SysError("could not execute chroot helper");
|
|
}
|
|
|
|
execvp(cmd.c_str(), stringsToCharPtrs(args).data());
|
|
|
|
throw SysError("unable to exec '%s'", cmd);
|
|
}
|
|
};
|
|
|
|
static RegisterCommand r1(make_ref<CmdRun>());
|
|
|
|
void chrootHelper(int argc, char * * argv)
|
|
{
|
|
int p = 1;
|
|
std::string storeDir = argv[p++];
|
|
std::string realStoreDir = argv[p++];
|
|
std::string cmd = argv[p++];
|
|
Strings args;
|
|
while (p < argc)
|
|
args.push_back(argv[p++]);
|
|
|
|
#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 (true /* !pathExists(storeDir) */) {
|
|
// FIXME: Use overlayfs?
|
|
|
|
Path tmpDir = createTempDir();
|
|
|
|
createDirs(tmpDir + storeDir);
|
|
|
|
if (mount(realStoreDir.c_str(), (tmpDir + storeDir).c_str(), "", MS_BIND, 0) == -1)
|
|
throw SysError("mounting '%s' on '%s'", realStoreDir, storeDir);
|
|
|
|
for (auto entry : readDirectory("/")) {
|
|
auto src = "/" + entry.name;
|
|
auto st = lstat(src);
|
|
if (!S_ISDIR(st.st_mode)) continue;
|
|
Path dst = tmpDir + "/" + entry.name;
|
|
if (pathExists(dst)) continue;
|
|
if (mkdir(dst.c_str(), 0700) == -1)
|
|
throw SysError("creating directory '%s'", dst);
|
|
if (mount(src.c_str(), dst.c_str(), "", MS_BIND | MS_REC, 0) == -1)
|
|
throw SysError("mounting '%s' on '%s'", src, 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(realStoreDir.c_str(), storeDir.c_str(), "", MS_BIND, 0) == -1)
|
|
throw SysError("mounting '%s' on '%s'", realStoreDir, storeDir);
|
|
|
|
writeFile("/proc/self/setgroups", "deny");
|
|
writeFile("/proc/self/uid_map", fmt("%d %d %d", uid, uid, 1));
|
|
writeFile("/proc/self/gid_map", fmt("%d %d %d", gid, gid, 1));
|
|
|
|
execvp(cmd.c_str(), stringsToCharPtrs(args).data());
|
|
|
|
throw SysError("unable to exec '%s'", cmd);
|
|
|
|
#else
|
|
throw Error("mounting the Nix store on '%s' is not supported on this platform", storeDir);
|
|
#endif
|
|
}
|