io: don't leave errno as a random value when we hit EOF.
[ccan] / ccan / io / io.c
index c0dd9b838e84af6ec8ef6b62dec8fe3695adf94c..bdcbf9e26b8f9f580fea08c2c0913d31efe9dcc7 100644 (file)
@@ -202,8 +202,12 @@ struct io_plan *io_write_(struct io_conn *conn, const void *data, size_t len,
 static int do_read(int fd, struct io_plan_arg *arg)
 {
        ssize_t ret = read(fd, arg->u1.cp, arg->u2.s);
-       if (ret <= 0)
+       if (ret <= 0) {
+               /* Errno isn't set if we hit EOF, so set it to distinct value */
+               if (ret == 0)
+                       errno = 0;
                return -1;
+       }
 
        arg->u1.cp += ret;
        arg->u2.s -= ret;
@@ -230,8 +234,12 @@ struct io_plan *io_read_(struct io_conn *conn,
 static int do_read_partial(int fd, struct io_plan_arg *arg)
 {
        ssize_t ret = read(fd, arg->u1.cp, *(size_t *)arg->u2.vp);
-       if (ret <= 0)
+       if (ret <= 0) {
+               /* Errno isn't set if we hit EOF, so set it to distinct value */
+               if (ret == 0)
+                       errno = 0;
                return -1;
+       }
 
        *(size_t *)arg->u2.vp = ret;
        return 1;