diff options
Diffstat (limited to 'src/linux/console.c')
| -rw-r--r-- | src/linux/console.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/linux/console.c b/src/linux/console.c new file mode 100644 index 00000000..dcffc701 --- /dev/null +++ b/src/linux/console.c @@ -0,0 +1,210 @@ +// 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 +static 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 + ****************************************************************/ + +static 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(); +} |