/* * Copyright (C) 1993 by Andrew A. Chernov, Moscow, Russia. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint char copyright[] = "@(#)Copyright (C) 1993 by Andrew A. Chernov, Moscow, Russia.\n\ All rights reserved.\n"; #endif /* not lint */ /* * Andrew A. Chernov Dec 20 1993 * * Fix kernel time value if machine run wall CMOS clock * (and /etc/wall_cmos_clock file present) * using zoneinfo rules or direct TZ environment variable set. * Use Joerg Wunsch idea for seconds accurate offset calculation * with Garrett Wollman and Bruce Evans fixes. * */ #include #include #include #include #include #include #include #include #include "pathnames.h" int main(argc, argv) int argc; char **argv; { struct tm local, utc; struct timeval tv, *stv; struct timezone tz, *stz; int kern_offset; size_t len; int mib[2]; /* Avoid time_t here, can be unsigned long or worse */ long offset, utcsec, localsec, diff; time_t initial_sec, final_sec; int ch, init = -1, verbose = 0; while ((ch = getopt(argc, argv, "aiv")) != EOF) switch((char)ch) { case 'i': /* initial call, save offset */ if (init != -1) goto usage; init = 1; break; case 'a': /* adjustment call, use saved offset */ if (init != -1) goto usage; init = 0; break; case 'v': /* verbose */ verbose = 1; break; default: usage: fprintf(stderr, "Usage:\n\ \tadjkerntz -i [-v]\t(initial call from /etc/rc)\n\ \tadjkerntz -a [-v]\t(adjustment call from crontab)\n"); return 2; } if (init == -1) goto usage; if (access(_PATH_CLOCK, F_OK)) return 0; /* Restore saved offset */ mib[0] = CTL_MACHDEP; mib[1] = CPU_ADJKERNTZ; len = sizeof(kern_offset); if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { perror("sysctl(get_offset)"); return 1; } /****** Critical section, do all things as fast as possible ******/ /* get local CMOS clock and possible kernel offset */ if (gettimeofday(&tv, &tz)) { perror("gettimeofday"); return 1; } /* get the actual local timezone difference */ initial_sec = tv.tv_sec; local = *localtime(&initial_sec); utc = *gmtime(&initial_sec); utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */ /* because it assumed local time */ /* calculate local CMOS diff from GMT */ utcsec = mktime(&utc); localsec = mktime(&local); if (utcsec == -1 || localsec == -1) { /* * XXX user can only control local time, and it is * unacceptable to fail here for -i. 2:30 am in the * middle of the nonexistent hour means 3:30 am. */ fprintf(stderr, "Nonexistent local time - try again in an hour\n"); return 1; } offset = utcsec - localsec; /* correct the kerneltime for this diffs */ /* subtract kernel offset, if present, old offset too */ diff = offset - tz.tz_minuteswest * 60 - kern_offset; if (diff != 0) { /* Yet one step for final time */ final_sec = tv.tv_sec + diff; /* get the actual local timezone difference */ local = *localtime(&final_sec); utc = *gmtime(&final_sec); utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */ /* because it assumed local time */ utcsec = mktime(&utc); localsec = mktime(&local); if (utcsec == -1 || localsec == -1) { /* * XXX as above. The user has even less control, * but perhaps we never get here. */ fprintf(stderr, "Nonexistent (final) local time - try again in an hour\n"); return 1; } offset = utcsec - localsec; /* correct the kerneltime for this diffs */ /* subtract kernel offset, if present, old offset too */ diff = offset - tz.tz_minuteswest * 60 - kern_offset; if (diff != 0) { tv.tv_sec += diff; tv.tv_usec = 0; /* we are restarting here... */ stv = &tv; } else stv = NULL; } else stv = NULL; if (kern_offset != offset) { kern_offset = offset; mib[0] = CTL_MACHDEP; mib[1] = CPU_ADJKERNTZ; len = sizeof(kern_offset); if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { perror("sysctl(update_offset)"); return 1; } } if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ stz = &tz; } else stz = NULL; if (stz != NULL || stv != NULL) { int disrtcset, need_restore = 0; if (init && stv != NULL) { mib[0] = CTL_MACHDEP; mib[1] = CPU_DISRTCSET; len = sizeof(disrtcset); if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { perror("sysctl(get_disrtcset)"); return 1; } if (disrtcset == 0) { disrtcset = 1; need_restore = 1; if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { perror("sysctl(set_disrtcset)"); return 1; } } } if (settimeofday(stv, stz)) { perror("settimeofday"); return 1; } if (need_restore) { disrtcset = 0; if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { perror("sysctl(restore_disrtcset)"); return 1; } } } /****** End of critical section ******/ if (verbose) printf("Calculated zone offset difference: %ld seconds\n", diff); return 0; }