tee(1): explicitly check read(2) return value for 0 and -1

diff --git a/usr.bin/tee/tee.c b/usr.bin/tee/tee.c
index 0ead177..e7e6fcf 100644 (file)
--- a/usr.bin/tee/tee.c
+++ b/usr.bin/tee/tee.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tee.c,v 1.14 2021/12/13 18:33:23 cheloha Exp $        */
+/*     $OpenBSD: tee.c,v 1.15 2023/03/04 00:00:25 cheloha Exp $        */
 /*     $NetBSD: tee.c,v 1.5 1994/12/09 01:43:39 jtc Exp $      */
 
 /*
@@ -114,7 +114,7 @@ main(int argc, char *argv[])
        buf = malloc(BSIZE);
        if (buf == NULL)
                err(1, NULL);
-       while ((rval = read(STDIN_FILENO, buf, BSIZE)) > 0) {
+       while ((rval = read(STDIN_FILENO, buf, BSIZE)) != 0 && rval != -1) {
                SLIST_FOREACH(p, &head, next) {
                        for (n = 0; n < rval; n += wval) {
                                wval = write(p->fd, buf + n, rval - n);