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nix run: Handle the case where the /nix/store mount point doesn't exist

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This commit is contained in:
Eelco Dolstra 2016-06-02 18:19:10 +02:00
parent a424ab0444
commit eda2aaae92
1 changed files with 39 additions and 2 deletions
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41
src/nix/run.cc
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@ -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