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authorEelco Dolstra <e.dolstra@tudelft.nl>2005-02-01T12·36+0000
committerEelco Dolstra <e.dolstra@tudelft.nl>2005-02-01T12·36+0000
commitdcc37c236c66ba463bd61fec23d046485d8a412f (patch)
treeb1a34feaf2a9a0ca0e0bad89c1671289de9e19d2 /scripts
parenta6b65fd5e107416588a6572a88518d8816abcb12 (diff)
* nix-store, nix-instantiate: added an option `--add-root' to
  immediately add the result as a permanent GC root.  This is the only
  way to prevent a race with the garbage collector.  For instance, the
  old style

    ln -s $(nix-store -r $(nix-instantiate foo.nix)) \
      /nix/var/nix/gcroots/result

  has two time windows in which the garbage collector can interfere
  (by GC'ing the derivation and the output, respectively).  On the
  other hand,

    nix-store --add-root /nix/var/nix/gcroots/result -r \
      $(nix-instantiate --add-root /nix/var/nix/gcroots/drv \
        foo.nix)

  is safe.

* nix-build: use `--add-root' to prevent GC races.

Diffstat (limited to 'scripts')
-rw-r--r--scripts/nix-build.in11
1 files changed, 9 insertions, 2 deletions
diff --git a/scripts/nix-build.in b/scripts/nix-build.in
index 5ae591f35168..33fbc61a3d20 100644
--- a/scripts/nix-build.in
+++ b/scripts/nix-build.in
@@ -10,6 +10,9 @@ fi
 extraArgs=
 noLink=
 
+userName=$USER
+if test -z "$username"; then userName="unknown"; fi
+
 for i in "$@"; do
     case "$i" in
         --no-link)
@@ -19,11 +22,15 @@ for i in "$@"; do
             extraArgs="$extraArgs $i"
             ;;
         *)
-            storeExprs=$(@bindir@/nix-instantiate "$i")
+            storeExprs=$(@bindir@/nix-instantiate \
+                --add-root "@localstatedir@/nix/gcroots/nix-build/$userName-drv" \
+                "$i")
             for j in $storeExprs; do
                 echo "store expression is $j" >&2
             done
-            outPaths=$(@bindir@/nix-store -rv $extraArgs $storeExprs)
+            outPaths=$(@bindir@/nix-store \
+                --add-root "@localstatedir@/nix/gcroots/nix-build/$userName-out" \
+                -rv $extraArgs $storeExprs)
             for j in $outPaths; do
                 echo "$j"
                 if test -z "$noLink"; then