[Qemu-devel] [PATCH v5 05/10] qemu-iotests: change qemu pid and fd tracking / cleanup

[Jeff Cody]

So that later patches can cleanup running qemu processes called from
different subshells, track resources to cleanup in pid and fd list
files.

In subsquent patches, ./check will kill all QEMU processes launched with
the common.qemu framework, and the tests will not need to cleanup
manually (unless they want to do so as part of the test, e.g. wait for
a process to end such as migration).

Signed-off-by: Jeff Cody <address@hidden>
---
 tests/qemu-iotests/common.qemu | 82 ++++++++++++++++++++++++++++++++----------
 tests/qemu-iotests/common.rc   |  3 +-
 2 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/tests/qemu-iotests/common.qemu b/tests/qemu-iotests/common.qemu
index 7b3052d..35a08a6 100644
--- a/tests/qemu-iotests/common.qemu
+++ b/tests/qemu-iotests/common.qemu
@@ -33,6 +33,10 @@ QEMU_FIFO_OUT="${QEMU_TEST_DIR}/qmp-out-$$"
 QEMU_HANDLE=0
 export _QEMU_HANDLE=0
 
+QEMU_PID_LIST="${QEMU_TEST_DIR}"/qemu-pid.lst
+QEMU_OUT_FD_LIST="${QEMU_TEST_DIR}"/qemu-out-fd.lst
+QEMU_IN_FD_LIST="${QEMU_TEST_DIR}"/qemu-in-fd.lst
+QEMU_FIFO_LIST="${QEMU_TEST_DIR}"/qemu-fifo.lst
 # If bash version is >= 4.1, these will be overwritten and dynamic
 # file descriptor values assigned.
 _out_fd=3
@@ -193,6 +197,10 @@ function _launch_qemu()
     QEMU_OUT[${_QEMU_HANDLE}]=${_out_fd}
     QEMU_IN[${_QEMU_HANDLE}]=${_in_fd}
     QEMU_STATUS[${_QEMU_HANDLE}]=0
+    echo ${_out_fd} >> "$QEMU_OUT_FD_LIST"
+    echo ${_in_fd} >> "$QEMU_IN_FD_LIST"
+    echo ${fifo_in} >> "$QEMU_FIFO_LIST"
+    echo ${fifo_out} >> "$QEMU_FIFO_LIST"
 
     if [ "${qemu_comm_method}" == "qmp" ]
     then
@@ -209,35 +217,71 @@ function _launch_qemu()
 
 # Silenty kills the QEMU process
 #
+# This is able to kill and clean up after QEMU processes without the
+# need for any subshell-specific variables, so long as the qemu-pidlist
+# and qemu-out-fd.list and qemu-in-fd.list files are properly maintained.
+#
 # If $wait is set to anything other than the empty string, the process will not
 # be killed but only waited for, and any output will be forwarded to stdout. If
 # $wait is empty, the process will be killed and all output will be suppressed.
 function _cleanup_qemu()
 {
-    # QEMU_PID[], QEMU_IN[], QEMU_OUT[] all use same indices
-    for i in "address@hidden"
+    local fifo_path=
+    local testdir_path=
+
+    if [ ! -e "${QEMU_PID_LIST}" ]; then
+        return
+    fi
+
+    # get line count, and therefore number of processes to kill
+    numproc=$(wc -l "${QEMU_PID_LIST}" | sed 's/\s.*//')
+
+    for i in $(seq 1 $numproc)
     do
         local QEMU_PID
-        if [ -f "${QEMU_TEST_DIR}/qemu-${i}.pid" ]; then
-            read QEMU_PID < "${QEMU_TEST_DIR}/qemu-${i}.pid"
-            rm -f "${QEMU_TEST_DIR}/qemu-${i}.pid"
-            if [ -z "${wait}" ] && [ -n "${QEMU_PID}" ]; then
-                kill -KILL ${QEMU_PID} 2>/dev/null
-            fi
-            if [ -n "${QEMU_PID}" ]; then
-                wait ${QEMU_PID} 2>/dev/null # silent kill
-            fi
+        local OUT_FD
+        local IN_FD
+        j=$(expr $i - 1)
+
+        QEMU_PID=$(tail -n+${i} "${QEMU_PID_LIST}" | head -n1)
+        OUT_FD=$(tail -n+${i} "${QEMU_OUT_FD_LIST}" | head -n1)
+        IN_FD=$(tail -n+${i} "${QEMU_IN_FD_LIST}" | head -n1)
+
+        if [ -z "${wait}" ] && [ -n "${QEMU_PID}" ]; then
+            kill -KILL ${QEMU_PID} 2>/dev/null
+        fi
+        if [ -n "${QEMU_PID}" ]; then
+            wait ${QEMU_PID} 2>/dev/null # silent kill
         fi
 
-        if [ -n "${wait}" ]; then
-            cat <&${QEMU_OUT[$i]} | _filter_testdir | _filter_qemu \
-                                  | _filter_qemu_io | _filter_qmp | _filter_hmp
+        if [ -n "${wait}" ] && [ -n "${OUT_FD}" ]; then
+            cat <&${OUT_FD} | _filter_testdir | _filter_qemu \
+                            | _filter_qemu_io | _filter_qmp | _filter_hmp
+        fi
+
+        if [ -n "${IN_FD}" ]; then
+            eval "exec ${IN_FD}<&-"   # close file descriptors
+        fi
+        if [ -n "${OUT_FD}" ]; then
+            eval "exec ${OUT_FD}<&-"
         fi
-        rm -f "${QEMU_FIFO_IN}_${i}" "${QEMU_FIFO_OUT}_${i}"
-        eval "exec ${QEMU_IN[$i]}<&-"   # close file descriptors
-        eval "exec ${QEMU_OUT[$i]}<&-"
 
-        unset QEMU_IN[$i]
-        unset QEMU_OUT[$i]
+        unset QEMU_IN[$j]
+        unset QEMU_OUT[$j]
     done
+
+    # The FIFOs do not correspond to process entry in the pidlist, so
+    # just clean them up afterwards
+    while read fifo_name
+    do
+        # make sure entries are inside the $TEST_DIR
+        fifo_path=$(dirname -z $(realpath "$fifo_name"))
+        testdir_path=$(realpath "$QEMU_TEST_DIR")
+        if [ "$fifo_path" == "$testdir_path" ]
+        then
+            rm -f "$fifo_name"
+        fi
+    done < "${QEMU_FIFO_LIST}"
+
+    rm -f "${QEMU_PID_LIST}" "${QEMU_OUT_FD_LIST}" "${QEMU_IN_FD_LIST}" 
"$QEMU_FIFO_LIST}"
 }
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index a345ffd..b26b02f 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -40,7 +40,6 @@ poke_file()
     printf "$3" | dd "of=$1" bs=1 "seek=$2" conv=notrunc &>/dev/null
 }
 
-
 if ! . ./common.config
     then
     echo "$0: failed to source common.config"
@@ -51,7 +50,7 @@ _qemu_wrapper()
 {
     (
         if [ -n "${QEMU_NEED_PID}" ]; then
-            echo $BASHPID > "${QEMU_TEST_DIR}/qemu-${_QEMU_HANDLE}.pid"
+            echo $BASHPID >> "${QEMU_TEST_DIR}/qemu-pid.lst"
         fi
         exec "$QEMU_PROG" $QEMU_OPTIONS "$@"
     )
-- 
2.9.5