We sometimes erroneously detected processes in other sessions as belonging to our session. Conseque…

build/install-chroot.sh

Index: build/install-chroot.sh
diff --git a/build/install-chroot.sh b/build/install-chroot.sh
index 155fc798b267237fad721a423b15a9e83c1b7f7e..0ef33d277cfcf152d6611781879ad4e8b57f76fa 100755
--- a/build/install-chroot.sh
+++ b/build/install-chroot.sh
@@ -498,6 +498,7 @@ while [ "$#" -ne 0 ]; do
 done
 
 session="$(schroot -c "${chroot}" -b)"
+export CHROOT_SESSION_ID="${session}"
 
 if [ $# -eq 0 ]; then
   schroot -c "${session}" -r -p
@@ -509,13 +510,33 @@ rc=$?
 
 i=$(schroot -c "${session}" -r -p ls -- -id /proc/self/root/. |
      awk '{ print $1 }') 2>/dev/null
+other_pids=
 while [ -n "$i" ]; do
-  pids=$(ls -id1 /proc/*/root/. 2>/dev/null |
+  pids=$({ ls -id1 /proc/*/root/. 2>/dev/null |

[jln (very slow on Chromium), 2013/07/23 00:41:20]

Add a comment to explain the set substraction magic here ?

          sed -e 's,^[^0-9]*'$i'.*/\([1-9][0-9]*\)/.*$,\1,
                  t
-                 d') >/dev/null 2>&1
-  [ -z "$pids" ] && break
-  kill -9 $pids
+                 d';
+         echo "${other_pids}";
+         echo "${other_pids}"; } | sort | uniq -u) >/dev/null 2>&1
+  # Kill all processes that are still left running in the session. This is
+  # typically an assortment of daemon processes that were started
+  # automatically. They result in us being unable to tear down the session
+  # cleanly.
+  [ -z "${pids}" ] && break
+  for j in $pids; do
+    # Unfortunately, the way that schroot sets up sessions has the
+    # side-effect of being unable to tell one session apart from another.
+    # This can result in us attempting to kill processes in other sessions.
+    # We make a best-effort to avoid doing so.
+    k="$( ( xargs -0 -n1 </proc/$j/environ ) 2>/dev/null |
+         sed 's/^CHROOT_SESSION_ID=/x/;t1;d;:1;q')"
+    if [ -n "${k}" -a "${k#x}" != "${session}" ]; then
+      other_pids="${other_pids}
+${j}"
+      continue
+    fi
+    kill -9 $pids
+  done
 done
 schroot -c "${session}" -e
 exit $rc