[PATCH v2] tests/9pfs: Use g_autofree and g_autoptr where possible

[Greg Kurz <groug@kaod.org>]

It is recommended to use g_autofree or g_autoptr as it reduces
the odds of introducing memory leaks in future changes. Let's do
that everywhere a glib allocation is performed.

The virtio_9p_create_local_test_dir() function needs some extra
care though : the template pointer is eventually cached into the
local_test_path global variable for the duration of the tests and
should not be freed. Add the g_autofree annotation but negate it
with g_steal_pointer() to make it clear that the pointer ownership
is dropped on purpose.

Based-on: <f6602123c6f7d0d593466231b04fba087817abbd.1642879848.git.qemu_oss@crudebyte.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
---
v2: - fix crash with local_test_path
---
 tests/qtest/libqos/virtio-9p.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/tests/qtest/libqos/virtio-9p.c b/tests/qtest/libqos/virtio-9p.c
index ef96ef006adc..f0ffbc583492 100644
--- a/tests/qtest/libqos/virtio-9p.c
+++ b/tests/qtest/libqos/virtio-9p.c
@@ -37,18 +37,22 @@ static char *concat_path(const char* a, const char* b)
     return g_build_filename(a, b, NULL);
 }
 
-void virtio_9p_create_local_test_dir(void)
+static char *make_temp_dir(char *template)
 {
-    struct stat st;
-    char *pwd = g_get_current_dir();
-    char *template = concat_path(pwd, "qtest-9p-local-XXXXXX");
-
-    local_test_path = mkdtemp(template);
-    if (!local_test_path) {
+    char *path = mkdtemp(template);
+    if (!path) {
         g_test_message("mkdtemp('%s') failed: %s", template, strerror(errno));
     }
-    g_free(pwd);
+    return path;
+}
+
+void virtio_9p_create_local_test_dir(void)
+{
+    g_autofree char *pwd = g_get_current_dir();
+    g_autofree char *template = concat_path(pwd, "qtest-9p-local-XXXXXX");
+    struct stat st;
 
+    local_test_path = make_temp_dir(g_steal_pointer(&template));
     g_assert(local_test_path != NULL);
 
     /* ensure test directory exists now ... */
@@ -60,12 +64,11 @@ void virtio_9p_create_local_test_dir(void)
 void virtio_9p_remove_local_test_dir(void)
 {
     g_assert(local_test_path != NULL);
-    char *cmd = g_strdup_printf("rm -fr '%s'\n", local_test_path);
+    g_autofree char *cmd = g_strdup_printf("rm -fr '%s'\n", local_test_path);
     int res = system(cmd);
     if (res < 0) {
         /* ignore error, dummy check to prevent compiler error */
     }
-    g_free(cmd);
 }
 
 char *virtio_9p_test_path(const char *path)
@@ -209,8 +212,8 @@ static void *virtio_9p_pci_create(void *pci_bus, QGuestAllocator *t_alloc,
 static void regex_replace(GString *haystack, const char *pattern,
                           const char *replace_fmt, ...)
 {
-    GRegex *regex;
-    char *replace, *s;
+    g_autoptr(GRegex) regex = NULL;
+    g_autofree char *replace = NULL, *s = NULL;
     va_list argp;
 
     va_start(argp, replace_fmt);
@@ -220,9 +223,6 @@ static void regex_replace(GString *haystack, const char *pattern,
     regex = g_regex_new(pattern, 0, 0, NULL);
     s = g_regex_replace(regex, haystack->str, -1, 0, replace, 0, NULL);
     g_string_assign(haystack, s);
-    g_free(s);
-    g_regex_unref(regex);
-    g_free(replace);
 }
 
 void virtio_9p_assign_local_driver(GString *cmd_line, const char *args)
-- 
2.34.1