tcwg-host: Fix kernel core pattern setting for the GDB testsuite

When starting the host container, take the opportunity to check and fix the
kernel.core_pattern sysctl to allow the GDB testsuite to check core files.

Change-Id: I1ef94220f7c4a76622d0edd33ad6026cf3a619ee

1 files changed, 26 insertions, 2 deletions

diff --git a/tcwg-base/tcwg-host/start.sh b/tcwg-base/tcwg-host/start.sh
index 5dd9928c..96095def 100755
--- a/tcwg-base/tcwg-host/start.sh
+++ b/tcwg-base/tcwg-host/start.sh
@@ -99,7 +99,8 @@ case "$(uname -m):$($DOCKER --version | cut -d" " -f3)" in
 esac
 
 # Since we're starting a host container, take the opportunity to ensure that GDB
-# can attach to test programs when running the testsuite.
+# can attach to test programs when running the testsuite, and that core files
+# are being correctly stored in the filesystem.
 (
     # Use "sudo sysctl" because there's no guarantee that this script is
     # running as root. And there's no guarantee that "sudo sysctl" will
@@ -108,13 +109,36 @@ esac
     set +e
     ptrace_scope=$(sudo sysctl -n kernel.yama.ptrace_scope)
     res=$?
+    ptrace_scope_config=""
     # If sysctl above failed (e.g., because this is a non-privileged
     # jenkins container), then do not attempt to change system configuration.
     if [ $res = 0 ] && [ "$ptrace_scope" != 0 ]; then
 	set -e
 	sudo sysctl -we kernel.yama.ptrace_scope=0
+	ptrace_scope_config="kernel.yama.ptrace_scope = 0"
+    fi
+
+    core_pattern=$(sudo sysctl -n kernel.core_pattern)
+    res=$?
+    core_pattern_config=""
+    # If sysctl above failed (e.g., because this is a non-privileged
+    # jenkins container), then do not attempt to change system configuration.
+    if [ $res = 0 ] && echo "$core_pattern" | grep -q -v -e '^core'; then
+	set -e
+	sudo sysctl -we kernel.core_pattern=core.%e.%p.%h.%t
+	core_pattern_config="
+# %e: executable filename
+# %p: PID
+# %h: hostname
+# %t: UNIX time of dump
+kernel.core_pattern = core.%e.%p.%h.%t"
+    fi
+
+    # If any sysctl change was made, persist it in a configuration file.
+    if [ -n "$ptrace_scope_config" ] || [ -n "$core_pattern_config" ]; then
 	sudo tee /etc/sysctl.d/90-tcwg.conf > /dev/null <<EOF
-kernel.yama.ptrace_scope = 0
+$ptrace_scope_config
+$core_pattern_config
 EOF
 	sudo chmod 644 /etc/sysctl.d/90-tcwg.conf
     fi