hw/openrisc/openrisc_sim: Avoid buffer overflow build error

Resolves this build breakage (which is actually a false-positive)

../hw/openrisc/openrisc_sim.c: In function ‘openrisc_sim_init’:
../hw/openrisc/openrisc_sim.c:284:45: error: ‘__builtin___snprintf_chk’ output may be truncated before the last format character [-Werror=format-truncation=]
     snprintf(alias, sizeof(alias), "serial%d", uart_idx);
                                             ^
In file included from /usr/include/stdio.h:964:0,
                 from /data/qemu/include/qemu/osdep.h:114,
                 from ../hw/openrisc/openrisc_sim.c:21:
/usr/include/bits/stdio2.h:54:10: note: ‘__builtin___snprintf_chk’ output between 8 and 9 bytes into a destination of size 8
   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __glibc_objsize (__s), __fmt,
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __va_arg_pack ());
        ~~~~~~~~~~~~~~~~~

by using a modern, more robust allocation pattern.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-ID: <298bd904-1ee9-439e-8220-7a24e0952861@siemens.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
index 880c8ebbb8b8595b7975a6db5571fd806e0ab71c..b7d9cdd900731679a2ad6ec9727dbd6c5b19b390 100644 (file)
--- a/hw/openrisc/openrisc_sim.c
+++ b/hw/openrisc/openrisc_sim.c
@@ -247,10 +247,10 @@ static void openrisc_sim_serial_init(Or1ksimState *state, hwaddr base,
                                      OpenRISCCPU *cpus[], int irq_pin,
                                      int uart_idx)
 {
+    g_autofree char *alias = g_strdup_printf("serial%d", uart_idx);
     void *fdt = state->fdt;
     char *nodename;
     qemu_irq serial_irq;
-    char alias[sizeof("serial0")];
     int i;
 
     if (num_cpus > 1) {
@@ -281,7 +281,6 @@ static void openrisc_sim_serial_init(Or1ksimState *state, hwaddr base,
         /* The /chosen node is created during fdt creation. */
         qemu_fdt_setprop_string(fdt, "/chosen", "stdout-path", nodename);
     }
-    snprintf(alias, sizeof(alias), "serial%d", uart_idx);
     qemu_fdt_setprop_string(fdt, "/aliases", alias, nodename);
 
     g_free(nodename);