[Qemu-devel] [PATCH v2] qdict: fix unbounded stack warning for qdict_array_entries

* [Qemu-devel] [PATCH v2] qdict: fix unbounded stack warning for qdict_array_entries
@ 2016-03-22  2:37 Peter Xu
  2016-03-22 15:39 ` Markus Armbruster
  0 siblings, 1 reply; 3+ messages in thread
From: Peter Xu @ 2016-03-22  2:37 UTC (permalink / raw)
  To: qemu-devel; +Cc: kwolf, pbonzini, armbru, peterx

Here we use one g_strdup_printf() to replace the two stack allocated
array, considering it's more convenient, safe, and as long as it's
called rarely only when quorum device opens. This will remove the
unbound stack warning when compiling with "-Wstack-usage=1000000".

Reviewed-by:   Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 qobject/qdict.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/qobject/qdict.c b/qobject/qdict.c
index 9833bd0..fe6ffa1 100644
--- a/qobject/qdict.c
+++ b/qobject/qdict.c
@@ -704,19 +704,16 @@ int qdict_array_entries(QDict *src, const char *subqdict)
     for (i = 0; i < INT_MAX; i++) {
         QObject *subqobj;
         int subqdict_entries;
-        size_t slen = 32 + subqdict_len;
-        char indexstr[slen], prefix[slen];
-        size_t snprintf_ret;
+        char *prefix = g_strdup_printf("%s%u.", subqdict, i);
 
-        snprintf_ret = snprintf(indexstr, slen, "%s%u", subqdict, i);
-        assert(snprintf_ret < slen);
+        subqdict_entries = qdict_count_prefixed_entries(src, prefix);
 
-        subqobj = qdict_get(src, indexstr);
+        /* Remove ending "." */
+        prefix[strlen(prefix) - 1] = 0;
+        subqobj = qdict_get(src, prefix);
 
-        snprintf_ret = snprintf(prefix, slen, "%s%u.", subqdict, i);
-        assert(snprintf_ret < slen);
+        g_free(prefix);
 
-        subqdict_entries = qdict_count_prefixed_entries(src, prefix);
         if (subqdict_entries < 0) {
             return subqdict_entries;
         }
-- 
2.4.3

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