FreeCalypso > hg > freecalypso-tools
view uptools/atinterf/fcup-atinterf.c @ 407:19e5a3e2f9c0
fcup-settime: moved time() retrieval a little closer to the output
A fundamental problem with all simple time transfer tools is that there is
always some delay between the time retrieval on the source system and that
transmitted time being set on the destination, and the resulting time
on the destination system is off by that delay amount. This delay cannot
be fully eliminated when working in a simple environment like ours,
but we should make our best effort to minimize it. In the present case,
moving the atinterf_init() call before the time() retrieval should make
a teensy-tiny improvement.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 11 Aug 2018 21:52:17 +0000 |
parents | cc207d81c05f |
children | 7eddc2578fdb |
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line source
#include <sys/types.h> #include <sys/time.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <unistd.h> extern int target_fd; FILE *target_rd; char response[515]; char command[513], message[513]; int cmd_with_msg; read_command_input(buf) char *buf; { char *nl; if (!fgets(buf, 513, stdin)) return(0); nl = index(buf, '\n'); if (!nl) { printf("Ecommand or message is too long\n"); exit(1); } *nl = '\0'; return(1); } send_to_target(cmd, term) char *cmd; { char *endp; int len, cc; endp = index(cmd, '\0'); *endp = term; len = endp - cmd + 1; cc = write(target_fd, cmd, len); *endp = '\0'; if (cc != len) { printf("Etarget write error\n"); exit(1); } } single_char_to_target(ch) { char buf = ch; int cc; cc = write(target_fd, &buf, 1); if (cc != 1) { printf("Etarget write error\n"); exit(1); } } collect_target_response() { char *nl; if (!fgets(response, 515, target_rd)) { printf("Etarget read error\n"); exit(1); } nl = index(response, '\n'); if (!nl) { printf("Etarget response is too long\n"); exit(1); } while (nl > response && nl[-1] == '\r') nl--; *nl = '\0'; } execute_command() { int c; send_to_target(command, '\r'); collect_target_response(); if (strcmp(command, response)) { printf("Efailed to get echo of command\n"); exit(1); } if (cmd_with_msg) { if ((c = getc(target_rd)) != '>') { ungetc(c, target_rd); collect_target_response(); printf("F%s\n", response); return; } if ((c = getc(target_rd)) != ' ') { ungetc(c, target_rd); collect_target_response(); printf("F%s\n", response); return; } send_to_target(message, '\032'); collect_target_response(); if (strcmp(message, response)) { printf("Efailed to get echo of message\n"); exit(1); } } for (;;) { collect_target_response(); if (!strcmp(response, "OK") || !strcmp(response, "ERROR") || !strcmp(response, "BUSY") || !strcmp(response, "NO CARRIER") || !strncmp(response, "+CME ERROR", 10) || !strncmp(response, "+CMS ERROR", 10)) { printf("F%s\n", response); return; } printf("I%s\n", response); } } wakeup_at() { single_char_to_target('A'); usleep(50000); single_char_to_target('T'); usleep(50000); single_char_to_target('\r'); collect_target_response(); if (response[0] && strcmp(response, "AT")) { badresp: printf("Ebad response to wakeup AT command\n"); exit(1); } collect_target_response(); if (strcmp(response, "OK")) goto badresp; } main(argc, argv) char **argv; { int wakeup_after_sec = 7; struct timeval curtime, last_time, timediff; if (argc < 3 || argc > 4) { fprintf(stderr, "usage: %s ttyport baudrate [wakeup-after-sec]\n", argv[0]); exit(1); } open_serial_port(argv[1]); set_fixed_baudrate(argv[2]); if (argc > 3) wakeup_after_sec = strtoul(argv[3], 0, 0); set_serial_nonblock(0); target_rd = fdopen(target_fd, "r"); if (!target_rd) { perror("fdopen"); exit(1); } bzero(&last_time, sizeof(struct timeval)); while (read_command_input(command)) { if (!strcasecmp(command, "c+m")) { cmd_with_msg = 1; if (!read_command_input(command)) break; if (!read_command_input(message)) break; } else cmd_with_msg = 0; if (wakeup_after_sec) { gettimeofday(&curtime, 0); timersub(&curtime, &last_time, &timediff); if (timediff.tv_sec >= wakeup_after_sec) wakeup_at(); bcopy(&curtime, &last_time, sizeof(struct timeval)); } execute_command(); fflush(stdout); } exit(0); }