/*
Called when there is buffered data for this client, and select() reports
that client's pipe is writable; so we should be able to flush some
buffered data.
*/
void write_buffered_data_to_client(int client_id)
{
switch (flush_client_data
(client_id, client_id, &clients[client_id].buffer)) {
case WRITE_STDIN_OK: // no more buffered data
clients[client_id].state &= ~CLIENT_OUTQ_FULL;
break;
case WRITE_STDIN_ERROR:
terminate_client_and_flush_data(client_id);
break;
case WRITE_STDIN_BUFFERED: // no room for all data, don't clear CLIENT_OUTQ_FULL flag
break;
default:
fprintf(stderr, "unknown flush_client_data?\n");
exit(1);
}
}
static void select_loop(libvchan_t *vchan)
{
fd_set select_set;
fd_set wr_set;
int max_fd;
int ret;
int vchan_fd;
sigset_t selectmask;
struct timespec zero_timeout = { 0, 0 };
struct timespec select_timeout = { 10, 0 };
struct buffer stdin_buf;
sigemptyset(&selectmask);
sigaddset(&selectmask, SIGCHLD);
sigprocmask(SIG_BLOCK, &selectmask, NULL);
sigemptyset(&selectmask);
buffer_init(&stdin_buf);
/* remember to set back to blocking mode before closing the FD - this may
* be not the only copy and some processes may misbehave when get
* nonblocking FD for input/output
*/
set_nonblock(local_stdin_fd);
for (;;) {
vchan_fd = libvchan_fd_for_select(vchan);
FD_ZERO(&select_set);
FD_ZERO(&wr_set);
FD_SET(vchan_fd, &select_set);
max_fd = vchan_fd;
if (local_stdout_fd != -1 &&
(size_t)libvchan_buffer_space(vchan) > sizeof(struct msg_header)) {
FD_SET(local_stdout_fd, &select_set);
if (local_stdout_fd > max_fd)
max_fd = local_stdout_fd;
}
if (child_exited && local_stdout_fd == -1)
check_child_status(vchan);
if (local_stdin_fd != -1 && buffer_len(&stdin_buf)) {
FD_SET(local_stdin_fd, &wr_set);
if (local_stdin_fd > max_fd)
max_fd = local_stdin_fd;
}
if ((local_stdin_fd == -1 || buffer_len(&stdin_buf) == 0) &&
libvchan_data_ready(vchan) > 0) {
/* check for other FDs, but exit immediately */
ret = pselect(max_fd + 1, &select_set, &wr_set, NULL,
&zero_timeout, &selectmask);
} else
ret = pselect(max_fd + 1, &select_set, &wr_set, NULL,
&select_timeout, &selectmask);
if (ret < 0) {
if (errno == EINTR && local_pid > 0) {
continue;
} else {
perror("select");
do_exit(1);
}
}
if (ret == 0) {
if (!libvchan_is_open(vchan)) {
/* remote disconnected witout a proper signaling */
do_exit(1);
}
}
if (FD_ISSET(vchan_fd, &select_set))
libvchan_wait(vchan);
if (buffer_len(&stdin_buf) &&
local_stdin_fd != -1 &&
FD_ISSET(local_stdin_fd, &wr_set)) {
if (flush_client_data(local_stdin_fd, &stdin_buf) == WRITE_STDIN_ERROR) {
perror("write stdin");
close(local_stdin_fd);
local_stdin_fd = -1;
}
}
while (libvchan_data_ready(vchan))
if (handle_vchan_data(vchan, &stdin_buf) != WRITE_STDIN_OK)
break;
if (local_stdout_fd != -1
&& FD_ISSET(local_stdout_fd, &select_set))
handle_input(vchan);
}
}
static int handle_vchan_data(libvchan_t *vchan, struct buffer *stdin_buf)
{
int status;
struct msg_header hdr;
char buf[MAX_DATA_CHUNK];
if (local_stdin_fd != -1) {
switch(flush_client_data(local_stdin_fd, stdin_buf)) {
case WRITE_STDIN_ERROR:
perror("write stdin");
close(local_stdin_fd);
local_stdin_fd = -1;
break;
case WRITE_STDIN_BUFFERED:
return WRITE_STDIN_BUFFERED;
case WRITE_STDIN_OK:
break;
}
}
if (libvchan_recv(vchan, &hdr, sizeof hdr) < 0) {
perror("read vchan");
do_exit(1);
}
if (hdr.len > MAX_DATA_CHUNK) {
fprintf(stderr, "client_header.len=%d\n", hdr.len);
do_exit(1);
}
if (!read_vchan_all(vchan, buf, hdr.len)) {
perror("read daemon");
do_exit(1);
}
switch (hdr.type) {
/* both directions because we can serve as either end of service call */
case MSG_DATA_STDIN:
case MSG_DATA_STDOUT:
if (local_stdin_fd == -1)
break;
if (replace_esc_stdout)
do_replace_esc(buf, hdr.len);
if (hdr.len == 0) {
/* restore flags, as we may have not the only copy of this file descriptor
*/
if (local_stdin_fd != -1)
set_block(local_stdin_fd);
close(local_stdin_fd);
local_stdin_fd = -1;
} else {
switch (write_stdin(local_stdin_fd, buf, hdr.len, stdin_buf)) {
case WRITE_STDIN_BUFFERED:
return WRITE_STDIN_BUFFERED;
case WRITE_STDIN_ERROR:
if (errno == EPIPE) {
// local process have closed its stdin, handle data in oposite
// direction (if any) before exit
close(local_stdin_fd);
local_stdin_fd = -1;
} else {
perror("write local stdout");
do_exit(1);
}
break;
case WRITE_STDIN_OK:
break;
}
}
break;
case MSG_DATA_STDERR:
if (replace_esc_stderr)
do_replace_esc(buf, hdr.len);
write_all(2, buf, hdr.len);
break;
case MSG_DATA_EXIT_CODE:
libvchan_close(vchan);
if (hdr.len < sizeof(status))
status = 255;
else
memcpy(&status, buf, sizeof(status));
flush_client_data(local_stdin_fd, stdin_buf);
do_exit(status);
break;
default:
fprintf(stderr, "unknown msg %d\n", hdr.type);
do_exit(1);
}
/* intentionally do not distinguish between _ERROR and _OK, because in case
* of write error, we simply eat the data - no way to report it to the
* other side */
return WRITE_STDIN_OK;
}