LXR toybox/toys/posix/date.c

   1/* date.c - set/get the date
   2 *
   3 * Copyright 2012 Andre Renaud <andre@bluewatersys.com>
   4 *
   5 * See http://opengroup.org/onlinepubs/9699919799/utilities/date.html
   6 *
   7 * Note: setting a 2 year date is 50 years back/forward from today,
   8 * not posix's hardwired magic dates.
   9
  10USE_DATE(NEWTOY(date, "d:D:r:u[!dr]", TOYFLAG_BIN))
  11
  12config DATE
  13  bool "date"
  14  default y
  15  help
  16    usage: date [-u] [-r FILE] [-d DATE] [+DISPLAY_FORMAT] [-D SET_FORMAT] [SET]
  17
  18    Set/get the current date/time. With no SET shows the current date.
  19
  20    Default SET format is "MMDDhhmm[[CC]YY][.ss]", that's (2 digits each)
  21    month, day, hour (0-23), and minute. Optionally century, year, and second.
  22    Also accepts "@UNIXTIME[.FRACTION]" as seconds since midnight Jan 1 1970.
  23
  24    -d  Show DATE instead of current time (convert date format)
  25    -D  +FORMAT for SET or -d (instead of MMDDhhmm[[CC]YY][.ss])
  26    -r  Use modification time of FILE instead of current date
  27    -u  Use UTC instead of current timezone
  28
  29    +FORMAT specifies display format string using strftime(3) syntax:
  30
  31    %% literal %             %n newline              %t tab
  32    %S seconds (00-60)       %M minute (00-59)       %m month (01-12)
  33    %H hour (0-23)           %I hour (01-12)         %p AM/PM
  34    %y short year (00-99)    %Y year                 %C century
  35    %a short weekday name    %A weekday name         %u day of week (1-7, 1=mon)
  36    %b short month name      %B month name           %Z timezone name
  37    %j day of year (001-366) %d day of month (01-31) %e day of month ( 1-31)
  38    %N nanosec (output only)
  39
  40    %U Week of year (0-53 start sunday)   %W Week of year (0-53 start monday)
  41    %V Week of year (1-53 start monday, week < 4 days not part of this year) 
  42
  43    %D = "%m/%d/%y"    %r = "%I : %M : %S %p"   %T = "%H:%M:%S"   %h = "%b"
  44    %x locale date     %X locale time           %c locale date/time
  45*/
  46
  47#define FOR_date
  48#include "toys.h"
  49
  50GLOBALS(
  51  char *file;
  52  char *setfmt;
  53  char *showdate;
  54
  55  unsigned nano;
  56)
  57
  58// Handle default posix date format (mmddhhmm[[cc]yy]) or @UNIX[.FRAC]
  59// returns 0 success, nonzero for error
  60static int parse_default(char *str, struct tm *tm)
  61{
  62  int len = 0;
  63
  64  // Parse @UNIXTIME[.FRACTION]
  65  if (*str == '@') {
  66    long long ll;
  67    time_t tt;
  68
  69    // Collect seconds and nanoseconds
  70    // Note: struct tm hasn't got a fractional seconds field, thus strptime()
  71    // doesn't support it, so store nanoseconds out of band (in globals).
  72    // tt and ll are separate because we can't guarantee time_t is 64 bit (yet).
  73    sscanf(str, "@%lld%n", &ll, &len);
  74    if (str[len]=='.') {
  75      str += len+1;
  76      for (len = 0; len<9; len++) {
  77        TT.nano *= 10;
  78        if (isdigit(str[len])) TT.nano += str[len]-'0';
  79      }
  80    }
  81    if (str[len]) return 1;
  82    tt = ll;
  83    gmtime_r(&tt, tm);
  84
  85    return 0;
  86  }
  87
  88  // Posix format
  89  sscanf(str, "%2u%2u%2u%2u%n", &tm->tm_mon, &tm->tm_mday, &tm->tm_hour,
  90    &tm->tm_min, &len);
  91  if (len != 8) return 1;
  92  str += len;
  93  tm->tm_mon--;
  94
  95  // If year specified, overwrite one we fetched earlier
  96  if (*str && *str != '.') {
  97    unsigned year;
  98
  99    len = 0;
 100    sscanf(str, "%u%n", &year, &len);
 101    if (len == 4) tm->tm_year = year - 1900;
 102    else if (len != 2) return 1;
 103    str += len;
 104
 105    // 2 digit years, next 50 years are "future", last 50 years are "past".
 106    // A "future" date in past is a century ahead.
 107    // A non-future date in the future is a century behind.
 108    if (len == 2) {
 109      unsigned r1 = tm->tm_year % 100, r2 = (tm->tm_year + 50) % 100,
 110        century = tm->tm_year - r1;
 111
 112      if ((r1 < r2) ? (r1 < year && year < r2) : (year < r1 || year > r2)) {
 113        if (year < r1) year += 100;
 114      } else if (year > r1) year -= 100;
 115      tm->tm_year = year + century;
 116    }
 117  }
 118  if (*str == '.') {
 119    len = 0;
 120    sscanf(str, ".%u%n", &tm->tm_sec, &len);
 121    str += len;
 122  } else tm->tm_sec = 0;
 123
 124  return *str;
 125}
 126
 127static void check_range(int a, int low, int high)
 128{
 129  if (a<low) error_exit("%d<%d", a, low);
 130  if (a>high) error_exit("%d>%d", a, high);
 131}
 132
 133// Print strftime plus %N escape(s). note: modifies fmt for %N
 134static void puts_time(char *fmt, struct tm *tm)
 135{
 136  char *s, *snap;
 137  long width = width;
 138
 139  for (s = fmt;;s++) {
 140
 141    // Find next %N or end
 142    if (*(snap = s) == '%') {
 143      width = isdigit(*++s) ? *(s++)-'0' : 9;
 144      if (*s && *s != 'N') continue;
 145    } else if (*s) continue;
 146
 147    // Don't modify input string if no %N (default format is constant string).
 148    if (*s) *snap = 0;
 149    if (!strftime(toybuf, sizeof(toybuf)-10, fmt, tm))
 150      perror_exit("bad format '%s'", fmt);
 151    if (*s) {
 152      snap = toybuf+strlen(toybuf);
 153      sprintf(snap, "%09u", TT.nano);
 154      snap[width] = 0;
 155    }
 156    fputs(toybuf, stdout);
 157    if (!*s || !*(fmt = s+1)) break;
 158  }
 159  xputc('\n');
 160}
 161
 162void date_main(void)
 163{
 164  char *setdate = *toys.optargs, *format_string = "%a %b %e %H:%M:%S %Z %Y";
 165  struct tm tm;
 166
 167  memset(&tm, 0, sizeof(struct tm));
 168
 169  if (TT.showdate) {
 170    if (TT.setfmt) {
 171      char *s = strptime(TT.showdate, TT.setfmt+(*TT.setfmt=='+'), &tm);
 172
 173      if (!s || *s) goto bad_showdate;
 174    } else if (parse_default(TT.showdate, &tm)) goto bad_showdate;
 175  } else {
 176    struct timespec ts;
 177    struct stat st;
 178
 179    if (TT.file) {
 180      xstat(TT.file, &st);
 181      ts = st.st_mtim;
 182    } else clock_gettime(CLOCK_REALTIME, &ts);
 183
 184    ((toys.optflags & FLAG_u) ? gmtime_r : localtime_r)(&ts.tv_sec, &tm);
 185    TT.nano = ts.tv_nsec;
 186  }
 187
 188  // Fall through if no arguments
 189  if (!setdate);
 190  // Display the date?
 191  else if (*setdate == '+') {
 192    format_string = toys.optargs[0]+1;
 193    setdate = toys.optargs[1];
 194
 195  // Set the date
 196  } else if (setdate) {
 197    char *tz;
 198    struct timeval tv;
 199    int u = toys.optflags & FLAG_u;
 200
 201    if (parse_default(setdate, &tm)) goto bad_setdate;
 202
 203    check_range(tm.tm_sec, 0, 60);
 204    check_range(tm.tm_min, 0, 59);
 205    check_range(tm.tm_hour, 0, 23);
 206    check_range(tm.tm_mday, 1, 31);
 207    check_range(tm.tm_mon, 0, 11);
 208
 209    if (u) {
 210      tz = getenv("TZ");
 211      setenv("TZ", "UTC", 1);
 212      tzset();
 213    }
 214    errno = 0;
 215    tv.tv_sec = mktime(&tm);
 216    if (errno) goto bad_setdate;
 217    if (u) {
 218      if (tz) setenv("TZ", tz, 1);
 219      else unsetenv("TZ");
 220      tzset();
 221    }
 222
 223    tv.tv_usec = TT.nano/1000;
 224    if (settimeofday(&tv, NULL) < 0) perror_msg("cannot set date");
 225  }
 226
 227  puts_time(format_string, &tm);
 228  return;
 229
 230bad_showdate:
 231  setdate = TT.showdate;
 232bad_setdate:
 233  perror_exit("bad date '%s'", setdate);
 234}
 235