fix unsynchronized access to FILE structure in fflush(0)

commit c002668eb0352e619ea7064e4940b397b4a6e68d inadvertently moved
the check for unflushed write buffer outside of the scope of the
existing lock.

diff --git a/src/stdio/fflush.c b/src/stdio/fflush.c
index c288106..bf1e843 100644 (file)
--- a/src/stdio/fflush.c
+++ b/src/stdio/fflush.c
@@ -9,8 +9,11 @@ int fflush(FILE *f)
        if (!f) {
                int r = __stdout_used ? fflush(__stdout_used) : 0;
 
-               for (f=*__ofl_lock(); f; f=f->next)
+               for (f=*__ofl_lock(); f; f=f->next) {
+                       FLOCK(f);
                        if (f->wpos > f->wbase) r |= fflush(f);
+                       FUNLOCK(f);
+               }
                __ofl_unlock();
 
                return r;