tests/qtest/libqtest: Fix detection of architecture for binaries without path

The qtests can be run directly by specifying the QEMU binary with the
QTEST_QEMU_BINARY environment variable, for example:

 $ QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/qtest/test-hmp

However, if you specify a binary without a path, for example with
QTEST_QEMU_BINARY=qemu-system-x86_64 if the QEMU binary is in your
$PATH, then the test currently simply crashes.

Let's try a little bit smarter here by looking for the final '-'
instead of the slash.

Message-Id: <20201012114816.43546-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 08929f5ff6..b9ff29055b 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -870,9 +870,14 @@ char *qtest_hmp(QTestState *s, const char *fmt, ...)
 const char *qtest_get_arch(void)
 {
     const char *qemu = qtest_qemu_binary();
-    const char *end = strrchr(qemu, '/');
+    const char *end = strrchr(qemu, '-');
 
-    return end + strlen("/qemu-system-");
+    if (!end) {
+        fprintf(stderr, "Can't determine architecture from binary name.\n");
+        abort();
+    }
+
+    return end + 1;
 }
 
 bool qtest_get_irq(QTestState *s, int num)