linux-user: fill ppid field in /proc/self/stat

Signed-off-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <mvmwnqnef5g.fsf@suse.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/syscall.c

@@ -7956,6 +7956,9 @@ static int open_self_stat(void *cpu_env, int fd)
             gchar *bin = g_strrstr(ts->bprm->argv[0], "/");
             bin = bin ? bin + 1 : ts->bprm->argv[0];
             g_string_printf(buf, "(%.15s) ", bin);
+        } else if (i == 3) {
+            /* ppid */
+            g_string_printf(buf, FMT_pid " ", getppid());
         } else if (i == 27) {
             /* stack bottom */
             g_string_printf(buf, TARGET_ABI_FMT_ld " ", ts->info->start_stack);