You can observe that 'spadclient' takes 100% CPU when running
in pipe:
echo ')lisp (progn (sleep 14) (sb-ext:quit))' | fricas -noclef
When the input from pipe drains, 'read' will return 0,
our current code interprets it as CTRL-D instead of EOF,
causing the process to enter into endless loop.
- Qian
diff --git a/src/lib/sockio-c.c b/src/lib/sockio-c.c
index d8a62999..ee545c19 100644
--- a/src/lib/sockio-c.c
+++ b/src/lib/sockio-c.c
@@ -796,10 +796,12 @@ remote_stdio(Sock *sock)
char buf[1024];
fd_set rd;
int len;
+ int stdin_is_terminal = isatty(0);
+ int stdin_available = 1;
while (1) {
FD_ZERO(&rd);
FD_SET(sock->socket,&rd);
- FD_SET(0, &rd);
+ if (stdin_available) FD_SET(0, &rd);
len = sselect(FD_SETSIZE, (fd_set *)&rd, (fd_set *)0, (fd_set *)0,
NULL);
if (len == -1) {
perror("stdio select");
@@ -812,7 +814,12 @@ remote_stdio(Sock *sock)
return;
}
if (len == 0) {
+ if (stdin_is_terminal) {
/* EOF (CTRL-D) received, ignore it for now */
+ } else {
+ /* stdin is connected to a pipe and it is closed. */
+ stdin_available = 0;
+ }
} else {
swrite(sock, buf, len, "writing to remote stdin");
}
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