Isolation: wired up cgroup to build system.

This commit enables the building of the cgroup code. This is only built
when the cgroupv2 filesystem is found.

If cgroupv2 support is found then

  cgroupv2: .................. YES

will be printed by ./configure

Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

4 files changed, 29 insertions, 0 deletions

diff --git a/auto/cgroup b/auto/cgroup
new file mode 100644
index 00000000..2262b2ef
--- /dev/null
+++ b/auto/cgroup
@@ -0,0 +1,22 @@
+# Copyright (C) Andrew Clayton
+# Copyright (C) F5, Inc.
+
+NXT_HAVE_CGROUP=NO
+
+if [ -f "/proc/mounts" ]; then
+    CGROUP=$(grep cgroup2 /proc/mounts | head -n 1 | cut -d " " -f 2)
+
+    if [ "$CGROUP" ]; then
+        NXT_HAVE_CGROUP=YES
+
+        cat << END >> $NXT_AUTO_CONFIG_H
+
+#ifndef NXT_HAVE_CGROUP
+#define NXT_HAVE_CGROUP  1
+#define NXT_CGROUP_ROOT  "$CGROUP"
+#endif
+
+END
+
+    fi
+fi
diff --git a/auto/sources b/auto/sources
index cebced3a..29f3c7b5 100644
--- a/auto/sources
+++ b/auto/sources
@@ -304,6 +304,11 @@ if [ "$NXT_HAVE_CLONE" = "YES" ]; then
 fi
 
 
+if [ "$NXT_HAVE_CGROUP" = "YES" ]; then
+    NXT_LIB_SRCS="$NXT_LIB_SRCS src/nxt_cgroup.c"
+fi
+
+
 if [ "$NXT_TEST_BUILD" = "YES" ]; then
     NXT_LIB_SRCS="$NXT_LIB_SRCS $NXT_TEST_BUILD_SRCS"
 fi
diff --git a/auto/summary b/auto/summary
index c8a49d08..51db0eae 100644
--- a/auto/summary
+++ b/auto/summary
@@ -31,6 +31,7 @@ Unit configuration summary:
   NJS support: ............... $NXT_NJS
 
   process isolation: ......... $NXT_ISOLATION
+  cgroupv2: .................. $NXT_HAVE_CGROUP
 
   debug logging: ............. $NXT_DEBUG
 
diff --git a/configure b/configure
index c21973eb..1d897f1d 100755
--- a/configure
+++ b/configure
@@ -129,6 +129,7 @@ if [ $NXT_REGEX = YES ]; then
     . auto/pcre
 fi
 
+. auto/cgroup
 . auto/isolation
 . auto/capability