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* Put the chroots under /nix/var/nix/chroots to reduce the risk of

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disasters involving `rm -rf' on bind mounts.  Will try the
  definitive fix (per-process mounts, apparently possible via the
  CLONE_NEWNS flag in clone()) some other time.
This commit is contained in:
Eelco Dolstra 2008-10-29 15:34:48 +00:00
parent c98ea254dc
commit 709b55ee02
4 changed files with 15 additions and 10 deletions
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1
src/libmain/shared.cc
View file

@ -138,6 +138,7 @@ static void initAndRun(int argc, char * * argv)
nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR)); nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR));
nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR)); nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR)); nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
nixChrootsDir = canonPath(getEnv("NIX_CHROOTS_DIR", nixStateDir + "/chroots"));
string subs = getEnv("NIX_SUBSTITUTERS", "default"); string subs = getEnv("NIX_SUBSTITUTERS", "default");
if (subs == "default") { if (subs == "default") {

17
src/libstore/build.cc
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@ -1710,16 +1710,13 @@ void DerivationGoal::startBuilder()
/* Create a temporary directory in which we set up the chroot /* Create a temporary directory in which we set up the chroot
environment using bind-mounts. environment using bind-mounts.
!!! Big danger here: since we're doing this in /tmp, there !!! Bind mounts are potentially dangerous: if the user
is a risk that the admin does something like "rm -rf cleans up his system by doing "rm -rf
/tmp/chroot-nix-*" to clean up aborted builds, and if some /nix/var/nix/chroots/*", this will recurse into /nix/store
of the bind-mounts are still active, then "rm -rf" will via the bind mounts (and potentially other parts of the
happily recurse into those mount points (thereby deleting, filesystem, depending on the setting of the
say, /nix/store). Ideally, chrootRootDir should be created in `build-chroot-dirs' option). */
some special location (maybe in /nix/var/nix) where Nix chrootRootDir = createTempDir(nixChrootsDir, "chroot-nix");
takes care of unmounting / deleting old chroots
automatically. */
chrootRootDir = createTempDir("", "chroot-nix");
/* Clean up the chroot directory automatically, but don't /* Clean up the chroot directory automatically, but don't
recurse; that would be very very bad if the unmount of a recurse; that would be very very bad if the unmount of a

1
src/libstore/globals.cc
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@ -16,6 +16,7 @@ string nixDBPath = "/UNINIT";
string nixConfDir = "/UNINIT"; string nixConfDir = "/UNINIT";
string nixLibexecDir = "/UNINIT"; string nixLibexecDir = "/UNINIT";
string nixBinDir = "/UNINIT"; string nixBinDir = "/UNINIT";
string nixChrootsDir = "/UNINIT";
bool keepFailed = false; bool keepFailed = false;
bool keepGoing = false; bool keepGoing = false;

6
src/libstore/globals.hh
View file

@ -35,6 +35,12 @@ extern string nixLibexecDir;
/* nixBinDir is the directory where the main programs are stored. */ /* nixBinDir is the directory where the main programs are stored. */
extern string nixBinDir; extern string nixBinDir;
/* nixChrootsDir is the directory where we create chroot environments
(when chroot builds are enabled). We don't put these under /tmp to
prevent "rm -rf /tmp" from recursing into /nix/store via the bind
mounts in the chroots. */
extern string nixChrootsDir;
/* Misc. global flags. */ /* Misc. global flags. */