vipw: fix short write handling in copyfile

Since `off` and `nr` approach each other, the for-loop ends prematurely
when at least half of the buffer was written.  I think under certain
conditions this could cause the copy to be incomplete.

Signed-off-by: Egor Chelak <egor.chelak@gmail.com>

diff --git a/login-utils/vipw.c b/login-utils/vipw.c
index a071b639dd03e1926c07405941de64479bd62a8e..38953b7f5923980d01e33e489a1caef494b78c54 100644 (file)
--- a/login-utils/vipw.c
+++ b/login-utils/vipw.c
@@ -94,7 +94,7 @@ static void copyfile(int from, int to)
        char buf[8 * 1024];
 
        while ((nr = read(from, buf, sizeof(buf))) > 0)
-               for (off = 0; off < nr; nr -= nw, off += nw)
+               for (off = 0; nr > 0; nr -= nw, off += nw)
                        if ((nw = write(to, buf + off, nr)) < 0)
                                pw_error(tmp_file, 1, 1);