diff options
| -rw-r--r-- | src/nix/run.cc | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/src/nix/run.cc b/src/nix/run.cc index ed1c2650c..00af5bb18 100644 --- a/src/nix/run.cc +++ b/src/nix/run.cc @@ -5,6 +5,7 @@ #include "store-api.hh" #include "derivations.hh" #include "local-store.hh" +#include "finally.hh" #if __linux__ #include <sys/mount.h> @@ -52,8 +53,44 @@ struct CmdRun : StoreCommand, MixInstallables if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == -1) throw SysError("setting up a private mount namespace"); - 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); + /* 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 |