[PATCH v2 09/13] util/hexdump: 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 in order to avoid:

  [426/1310] Compiling C object libqemuutil.a.p/util_hexdump.c.o
  util/hexdump.c:35:21: 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]
            line += sprintf(line, " %02x", (unsigned char)buf[b + i]);
                    ^
  util/hexdump.c:37:21: warning: 'sprintf' is deprecated:
            line += sprintf(line, "   ");
                    ^
  2 warnings generated.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 util/hexdump.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/util/hexdump.c b/util/hexdump.c
index b6f70e93bb..2ec1171de3 100644
--- a/util/hexdump.c
+++ b/util/hexdump.c
@@ -19,7 +19,7 @@
 char *qemu_hexdump_line(const void *bufptr, unsigned offset,
                         unsigned int len, bool ascii)
 {
-    char linebuf[QEMU_HEXDUMP_LINE_BYTES], *line = linebuf;
+    g_autoptr(GString) gs = g_string_sized_new(QEMU_HEXDUMP_LINE_BYTES);
     const char *buf = bufptr;
     int i, c;
 
@@ -27,30 +27,29 @@ char *qemu_hexdump_line(const void *bufptr, unsigned offset,
         len = QEMU_HEXDUMP_LINE_BYTES;
     }
 
-    line += snprintf(line, 6, "%04x:", offset);
+    g_string_append_printf(gs, "%04x:", offset);
     for (i = 0; i < QEMU_HEXDUMP_LINE_BYTES; i++) {
         if ((i % 4) == 0) {
-            *line++ = ' ';
+            g_string_append_c(gs, ' ');
         }
         if (i < len) {
-            line += sprintf(line, " %02x", (unsigned char)buf[offset + i]);
+            g_string_append_printf(gs, " %02x", (unsigned char)buf[offset + i]);
         } else {
-            line += sprintf(line, "   ");
+            g_string_append(gs, "   ");
         }
     }
     if (ascii) {
-        *line++ = ' ';
+        g_string_append_c(gs, ' ');
         for (i = 0; i < len; i++) {
             c = buf[offset + i];
             if (c < ' ' || c > '~') {
                 c = '.';
             }
-            *line++ = c;
+            g_string_append_c(gs, c);
         }
     }
-    *line = '\0';
 
-    return g_strdup(linebuf);
+    return g_strdup(gs->str);
 }
 
 void qemu_hexdump(FILE *fp, const char *prefix,
-- 
2.41.0