[PATCH 05/12] system/qtest: Replace sprintf() by g_string_append_printf()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

sprintf() is deprecated on Darwin since macOS 13.0 / XCode 14.1,
resulting in painful developper experience.

Replace sprintf() by GString API uses in order to avoid:

  [120/169] Compiling C object libcommon.fa.p/system_qtest.c.o
  system/qtest.c:623:13: warning: 'sprintf' is deprecated:
    This function is provided for compatibility reasons only.
    Due to security concerns inherent in the design of sprintf(3),
    it is highly recommended that you use snprintf(3) instead.
    [-Wdeprecated-declarations]
            sprintf(&enc[i * 2], "%02x", data[i]);
            ^
  1 warning generated.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 system/qtest.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/system/qtest.c b/system/qtest.c
index 6da58b3874..22bf1a33dc 100644
--- a/system/qtest.c
+++ b/system/qtest.c
@@ -601,9 +601,9 @@ static void qtest_process_command(CharBackend *chr, gchar **words)
         qtest_send_prefix(chr);
         qtest_sendf(chr, "OK 0x%016" PRIx64 "\n", value);
     } else if (strcmp(words[0], "read") == 0) {
+        g_autoptr(GString) enc = g_string_new("");
         uint64_t addr, len, i;
         uint8_t *data;
-        char *enc;
         int ret;
 
         g_assert(words[1] && words[2]);
@@ -618,16 +618,14 @@ static void qtest_process_command(CharBackend *chr, gchar **words)
         address_space_read(first_cpu->as, addr, MEMTXATTRS_UNSPECIFIED, data,
                            len);
 
-        enc = g_malloc(2 * len + 1);
         for (i = 0; i < len; i++) {
-            sprintf(&enc[i * 2], "%02x", data[i]);
+            g_string_append_printf(enc, "%02x", data[i]);
         }
 
         qtest_send_prefix(chr);
-        qtest_sendf(chr, "OK 0x%s\n", enc);
+        qtest_sendf(chr, "OK 0x%s\n", enc->str);
 
         g_free(data);
-        g_free(enc);
     } else if (strcmp(words[0], "b64read") == 0) {
         uint64_t addr, len;
         uint8_t *data;
-- 
2.41.0