[PATCH v2 2/9] tests/qtest: Introduce qtest_init_with_env

[Fabiano Rosas <farosas@suse.de>]

Add a version of qtest_init() that takes an environment variable
containing the path of the QEMU binary. This allows tests to use more
than one QEMU binary.

If no variable is provided or the environment variable does not exist,
that is not an error. Fallback to using QTEST_QEMU_BINARY.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 tests/qtest/libqtest.c | 26 +++++++++++++++++++-------
 tests/qtest/libqtest.h | 13 +++++++++++++
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 1f971b98e0..88b79cb477 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -388,7 +388,8 @@ static pid_t qtest_create_process(char *cmd)
 }
 #endif /* _WIN32 */
 
-static QTestState *G_GNUC_PRINTF(1, 2) qtest_spawn_qemu(const char *fmt, ...)
+static QTestState *G_GNUC_PRINTF(2, 3) qtest_spawn_qemu(const char *qemu_bin,
+                                                        const char *fmt, ...)
 {
     va_list ap;
     QTestState *s = g_new0(QTestState, 1);
@@ -398,8 +399,7 @@ static QTestState *G_GNUC_PRINTF(1, 2) qtest_spawn_qemu(const char *fmt, ...)
     g_autoptr(GString) command = g_string_new("");
 
     va_start(ap, fmt);
-    g_string_append_printf(command, CMD_EXEC "%s %s",
-                           qtest_qemu_binary(NULL), tracearg);
+    g_string_append_printf(command, CMD_EXEC "%s %s", qemu_bin, tracearg);
     g_string_append_vprintf(command, fmt, ap);
     va_end(ap);
 
@@ -441,7 +441,8 @@ static QTestState *G_GNUC_PRINTF(1, 2) qtest_spawn_qemu(const char *fmt, ...)
     return s;
 }
 
-QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
+static QTestState *qtest_init_internal(const char *qemu_bin,
+                                       const char *extra_args)
 {
     QTestState *s;
     int sock, qmpsock, i;
@@ -466,7 +467,8 @@ QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
     sock = init_socket(socket_path);
     qmpsock = init_socket(qmp_socket_path);
 
-    s = qtest_spawn_qemu("-qtest unix:%s "
+    s = qtest_spawn_qemu(qemu_bin,
+                         "-qtest unix:%s "
                          "-qtest-log %s "
                          "-chardev socket,path=%s,id=char0 "
                          "-mon chardev=char0,mode=control "
@@ -518,9 +520,14 @@ QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
     return s;
 }
 
-QTestState *qtest_init(const char *extra_args)
+QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
 {
-    QTestState *s = qtest_init_without_qmp_handshake(extra_args);
+    return qtest_init_internal(qtest_qemu_binary(NULL), extra_args);
+}
+
+QTestState *qtest_init_with_env(const char *var, const char *extra_args)
+{
+    QTestState *s = qtest_init_internal(qtest_qemu_binary(var), extra_args);
     QDict *greeting;
 
     /* Read the QMP greeting and then do the handshake */
@@ -531,6 +538,11 @@ QTestState *qtest_init(const char *extra_args)
     return s;
 }
 
+QTestState *qtest_init(const char *extra_args)
+{
+    return qtest_init_with_env(NULL, extra_args);
+}
+
 QTestState *qtest_vinitf(const char *fmt, va_list ap)
 {
     char *args = g_strdup_vprintf(fmt, ap);
diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
index e53e350e3a..eef3a11ca4 100644
--- a/tests/qtest/libqtest.h
+++ b/tests/qtest/libqtest.h
@@ -55,6 +55,19 @@ QTestState *qtest_vinitf(const char *fmt, va_list ap) G_GNUC_PRINTF(1, 0);
  */
 QTestState *qtest_init(const char *extra_args);
 
+/**
+ * qtest_init_with_env:
+ * @var: Environment variable from where to take the QEMU binary
+ * @extra_args: Other arguments to pass to QEMU.  CAUTION: these
+ * arguments are subject to word splitting and shell evaluation.
+ *
+ * Like qtest_init(), but use a different environment variable for the
+ * QEMU binary.
+ *
+ * Returns: #QTestState instance.
+ */
+QTestState *qtest_init_with_env(const char *var, const char *extra_args);
+
 /**
  * qtest_init_without_qmp_handshake:
  * @extra_args: other arguments to pass to QEMU.  CAUTION: these
-- 
2.35.3