[PATCH] os-posix: simplify os_find_datadir

[Paolo Bonzini <pbonzini@redhat.com>]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Use g_build_filename instead of sprintf, and g_autofree instead of
manual freeing.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 os-posix.c | 41 +++++++++++++----------------------------
 1 file changed, 13 insertions(+), 28 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index 86cffd2..3cd52e1 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -80,41 +80,26 @@ void os_setup_signal_handling(void)
     sigaction(SIGTERM, &act, NULL);
 }
 
-/* Find a likely location for support files using the location of the binary.
-   For installed binaries this will be "$bindir/../share/qemu".  When
-   running from the build tree this will be "$bindir/../pc-bios".  */
-#define SHARE_SUFFIX "/share/qemu"
-#define BUILD_SUFFIX "/pc-bios"
+/*
+ * Find a likely location for support files using the location of the binary.
+ * When running from the build tree this will be "$bindir/../pc-bios".
+ * Otherwise, this is CONFIG_QEMU_DATADIR.
+ */
 char *os_find_datadir(void)
 {
-    char *dir, *exec_dir;
-    char *res;
-    size_t max_len;
+    g_autofree char *exec_dir = NULL;
+    g_autofree char *dir = NULL;
 
     exec_dir = qemu_get_exec_dir();
-    if (exec_dir == NULL) {
-        return NULL;
-    }
-    dir = g_path_get_dirname(exec_dir);
-
-    max_len = strlen(dir) +
-        MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;
-    res = g_malloc0(max_len);
-    snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);
-    if (access(res, R_OK)) {
-        snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);
-        if (access(res, R_OK)) {
-            g_free(res);
-            res = NULL;
-        }
+    g_return_val_if_fail(exec_dir != NULL, NULL);
+
+    dir = g_build_filename(exec_dir, "..", "pc-bios", NULL);
+    if (g_file_test(dir, G_FILE_TEST_IS_DIR)) {
+        return g_steal_pointer(&dir);
     }
 
-    g_free(dir);
-    g_free(exec_dir);
-    return res;
+    return g_strdup(CONFIG_QEMU_DATADIR);
 }
-#undef SHARE_SUFFIX
-#undef BUILD_SUFFIX
 
 void os_set_proc_name(const char *s)
 {
-- 
1.8.3.1