qtest resource cleanup pull request

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Merge remote-tracking branch 'remotes/stefanha/tags/qtest-monitor-process-pull-request' into staging

qtest resource cleanup pull request

# gpg: Signature made Wed 19 Feb 2014 14:46:34 GMT using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/qtest-monitor-process-pull-request:
  qtest: kill QEMU process on g_assert() failure
  qtest: make QEMU our direct child process
  qtest: drop unused child_pid field

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

tests/libqtest.c

@@ -43,8 +43,8 @@ struct QTestState
     int qmp_fd;
     bool irq_level[MAX_IRQ];
     GString *rx;
-    int child_pid;   /* Child process created to execute QEMU */
+    pid_t qemu_pid;  /* our child QEMU process */
-    pid_t qemu_pid;  /* QEMU process spawned by our child */
+    struct sigaction sigact_old; /* restored on exit */
 };
 
 #define g_assert_no_errno(ret) do { \
@@ -89,20 +89,17 @@ static int socket_accept(int sock)
     return ret;
 }
 
-static pid_t read_pid_file(const char *pid_file)
+static void kill_qemu(QTestState *s)
 {
-    FILE *f;
+    if (s->qemu_pid != -1) {
-    char buffer[1024];
+        kill(s->qemu_pid, SIGTERM);
-    pid_t pid = -1;
+        waitpid(s->qemu_pid, NULL, 0);
-
-    f = fopen(pid_file, "r");
-    if (f) {
-        if (fgets(buffer, sizeof(buffer), f)) {
-            pid = atoi(buffer);
-        }
-        fclose(f);
     }
-    return pid;
+}
+
+static void sigabrt_handler(int signo)
+{
+    kill_qemu(global_qtest);
 }
 
 QTestState *qtest_init(const char *extra_args)
@@ -111,10 +108,9 @@ QTestState *qtest_init(const char *extra_args)
     int sock, qmpsock, i;
     gchar *socket_path;
     gchar *qmp_socket_path;
-    gchar *pid_file;
     gchar *command;
     const char *qemu_binary;
-    pid_t pid;
+    struct sigaction sigact;
 
     qemu_binary = getenv("QTEST_QEMU_BINARY");
     g_assert(qemu_binary != NULL);
@@ -123,22 +119,28 @@ QTestState *qtest_init(const char *extra_args)
 
     socket_path = g_strdup_printf("/tmp/qtest-%d.sock", getpid());
     qmp_socket_path = g_strdup_printf("/tmp/qtest-%d.qmp", getpid());
-    pid_file = g_strdup_printf("/tmp/qtest-%d.pid", getpid());
 
     sock = init_socket(socket_path);
     qmpsock = init_socket(qmp_socket_path);
 
-    pid = fork();
+    /* Catch SIGABRT to clean up on g_assert() failure */
-    if (pid == 0) {
+    sigact = (struct sigaction){
-        command = g_strdup_printf("%s "
+        .sa_handler = sigabrt_handler,
+        .sa_flags = SA_RESETHAND,
+    };
+    sigemptyset(&sigact.sa_mask);
+    sigaction(SIGABRT, &sigact, &s->sigact_old);
+
+    s->qemu_pid = fork();
+    if (s->qemu_pid == 0) {
+        command = g_strdup_printf("exec %s "
                                   "-qtest unix:%s,nowait "
                                   "-qtest-log /dev/null "
                                   "-qmp unix:%s,nowait "
-                                  "-pidfile %s "
                                   "-machine accel=qtest "
                                   "-display none "
                                   "%s", qemu_binary, socket_path,
-                                  qmp_socket_path, pid_file,
+                                  qmp_socket_path,
                                   extra_args ?: "");
         execlp("/bin/sh", "sh", "-c", command, NULL);
         exit(1);
@@ -152,7 +154,6 @@ QTestState *qtest_init(const char *extra_args)
     g_free(qmp_socket_path);
 
     s->rx = g_string_new("");
-    s->child_pid = pid;
     for (i = 0; i < MAX_IRQ; i++) {
         s->irq_level[i] = false;
     }
@@ -161,10 +162,6 @@ QTestState *qtest_init(const char *extra_args)
     qtest_qmp_discard_response(s, "");
     qtest_qmp_discard_response(s, "{ 'execute': 'qmp_capabilities' }");
 
-    s->qemu_pid = read_pid_file(pid_file);
-    unlink(pid_file);
-    g_free(pid_file);
-
     if (getenv("QTEST_STOP")) {
         kill(s->qemu_pid, SIGSTOP);
     }
@@ -174,13 +171,9 @@ QTestState *qtest_init(const char *extra_args)
 
 void qtest_quit(QTestState *s)
 {
-    int status;
+    sigaction(SIGABRT, &s->sigact_old, NULL);
-
-    if (s->qemu_pid != -1) {
-        kill(s->qemu_pid, SIGTERM);
-        waitpid(s->qemu_pid, &status, 0);
-    }
 
+    kill_qemu(s);
     close(s->fd);
     close(s->qmp_fd);
     g_string_free(s->rx, true);