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// TTY based IO
//
// Copyright (C) 2017 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <errno.h> // errno
#include <fcntl.h> // fcntl
#include <poll.h> // poll
#include <pty.h> // openpty
#include <stdio.h> // fprintf
#include <string.h> // memmove
#include <sys/stat.h> // chmod
#include <sys/timerfd.h> // timerfd_create
#include <time.h> // struct timespec
#include <unistd.h> // ttyname
#include "board/irq.h" // irq_poll
#include "board/misc.h" // console_sendf
#include "command.h" // command_find_block
#include "internal.h" // console_setup
#include "sched.h" // sched_wake_task
static struct pollfd main_pfd[2];
#define MP_TIMER_IDX 0
#define MP_TTY_IDX 1
// Report 'errno' in a message written to stderr
void
report_errno(char *where, int rc)
{
int e = errno;
fprintf(stderr, "Got error %d in %s: (%d)%s\n", rc, where, e, strerror(e));
}
/****************************************************************
* Setup
****************************************************************/
int
set_non_blocking(int fd)
{
int flags = fcntl(fd, F_GETFL);
if (flags < 0) {
report_errno("fcntl getfl", flags);
return -1;
}
int ret = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
if (ret < 0) {
report_errno("fcntl setfl", flags);
return -1;
}
return 0;
}
static int
set_close_on_exec(int fd)
{
int ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
if (ret < 0) {
report_errno("fcntl set cloexec", ret);
return -1;
}
return 0;
}
int
console_setup(char *name)
{
// Open pseudo-tty
struct termios ti;
memset(&ti, 0, sizeof(ti));
int mfd, sfd, ret = openpty(&mfd, &sfd, NULL, &ti, NULL);
if (ret) {
report_errno("openpty", ret);
return -1;
}
ret = set_non_blocking(mfd);
if (ret)
return -1;
ret = set_close_on_exec(mfd);
if (ret)
return -1;
ret = set_close_on_exec(sfd);
if (ret)
return -1;
main_pfd[MP_TTY_IDX].fd = mfd;
main_pfd[MP_TTY_IDX].events = POLLIN;
// Create symlink to tty
unlink(name);
char *tname = ttyname(sfd);
if (!tname) {
report_errno("ttyname", 0);
return -1;
}
ret = symlink(tname, name);
if (ret) {
report_errno("symlink", ret);
return -1;
}
ret = chmod(tname, 0660);
if (ret) {
report_errno("chmod", ret);
return -1;
}
// Make sure stderr is non-blocking
ret = set_non_blocking(STDERR_FILENO);
if (ret)
return -1;
// Create sleep wakeup timer fd
ret = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC|TFD_NONBLOCK);
if (ret < 0) {
report_errno("timerfd_create", ret);
return -1;
}
main_pfd[MP_TIMER_IDX].fd = ret;
main_pfd[MP_TIMER_IDX].events = POLLIN;
return 0;
}
/****************************************************************
* Console handling
****************************************************************/
static struct task_wake console_wake;
static char receive_buf[4096];
static int receive_pos;
// Process any incoming commands
void
console_task(void)
{
if (!sched_check_wake(&console_wake))
return;
// Read data
int ret = read(main_pfd[MP_TTY_IDX].fd, &receive_buf[receive_pos]
, sizeof(receive_buf) - receive_pos);
if (ret < 0) {
if (errno == EWOULDBLOCK) {
ret = 0;
} else {
report_errno("read", ret);
return;
}
}
if (ret == 15 && receive_buf[receive_pos+14] == '\n'
&& memcmp(&receive_buf[receive_pos], "FORCE_SHUTDOWN\n", 15) == 0)
shutdown("Force shutdown command");
// Find and dispatch message blocks in the input
int len = receive_pos + ret;
uint8_t pop_count, msglen = len > MESSAGE_MAX ? MESSAGE_MAX : len;
ret = command_find_block(receive_buf, msglen, &pop_count);
if (ret > 0)
command_dispatch(receive_buf, pop_count);
if (ret) {
len -= pop_count;
if (len) {
memmove(receive_buf, &receive_buf[pop_count], len);
sched_wake_task(&console_wake);
}
}
receive_pos = len;
}
DECL_TASK(console_task);
// Encode and transmit a "response" message
void
console_sendf(const struct command_encoder *ce, va_list args)
{
// Generate message
char buf[MESSAGE_MAX];
uint8_t msglen = command_encodef(buf, ce, args);
command_add_frame(buf, msglen);
// Transmit message
int ret = write(main_pfd[MP_TTY_IDX].fd, buf, msglen);
if (ret < 0)
report_errno("write", ret);
}
// Sleep until the specified time (waking early for console input if needed)
void
console_sleep(struct timespec ts)
{
struct itimerspec its;
its.it_interval = (struct timespec){0, 0};
its.it_value = ts;
int ret = timerfd_settime(main_pfd[MP_TIMER_IDX].fd, TFD_TIMER_ABSTIME
, &its, NULL);
if (ret < 0) {
report_errno("timerfd_settime", ret);
return;
}
ret = poll(main_pfd, ARRAY_SIZE(main_pfd), -1);
if (ret <= 0) {
report_errno("poll main_pfd", ret);
return;
}
if (main_pfd[MP_TTY_IDX].revents)
sched_wake_task(&console_wake);
if (main_pfd[MP_TIMER_IDX].revents)
irq_poll();
}
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