date.c

   1 /*
   2  * Copyright (c) 1985, 1987, 1988 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * advertising materials, and other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  */
  17
  18 #include "private.h"
  19 #include "locale.h"
  20
  21 /*
  22 ** The two things date knows about time are. . .
  23 */
  24
  25 #ifndef TM_YEAR_BASE
  26 #define TM_YEAR_BASE    1900
  27 #endif /* !defined TM_YEAR_BASE */
  28
  29 #ifndef SECSPERMIN
  30 #define SECSPERMIN      60
  31 #endif /* !defined SECSPERMIN */
  32
  33 extern char **          environ;
  34 extern char *           optarg;
  35 extern int              optind;
  36 extern char *           tzname[2];
  37
  38 static int              retval = EXIT_SUCCESS;
  39
  40 static void             display(const char *, time_t);
  41 static void             dogmt(void);
  42 static void             errensure(void);
  43 static void             timeout(FILE *, const char *, const struct tm *);
  44 static void             usage(void);
  45
  46 int
  47 main(const int argc, char *argv[])
  48 {
  49         register const char *   format;
  50         register const char *   cp;
  51         register int            ch;
  52         register bool           rflag = false;
  53         time_t                  t;
  54         intmax_t                secs;
  55         char *                  endarg;
  56
  57 #ifdef LC_ALL
  58         setlocale(LC_ALL, "");
  59 #endif /* defined(LC_ALL) */
  60 #if HAVE_GETTEXT
  61 #ifdef TZ_DOMAINDIR
  62         bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
  63 #endif /* defined(TEXTDOMAINDIR) */
  64         textdomain(TZ_DOMAIN);
  65 #endif /* HAVE_GETTEXT */
  66         t = time(NULL);
  67         format = NULL;
  68         while ((ch = getopt(argc, argv, "ucr:")) != EOF && ch != -1) {
  69                 switch (ch) {
  70                 default:
  71                         usage();
  72                 case 'u':               /* do it in UT */
  73                 case 'c':
  74                         dogmt();
  75                         break;
  76                 case 'r':               /* seconds since 1970 */
  77                         if (rflag) {
  78                                 fprintf(stderr,
  79                                         _("date: error: multiple -r's used"));
  80                                 usage();
  81                         }
  82                         rflag = true;
  83                         errno = 0;
  84                         secs = strtoimax (optarg, &endarg, 0);
  85                         if (*endarg || optarg == endarg)
  86                                 errno = EINVAL;
  87                         else if (! (time_t_min <= secs && secs <= time_t_max))
  88                                 errno = ERANGE;
  89                         if (errno) {
  90                                 perror(optarg);
  91                                 errensure();
  92                                 exit(retval);
  93                         }
  94                         t = secs;
  95                         break;
  96                 }
  97         }
  98         while (optind < argc) {
  99                 cp = argv[optind++];
 100                 if (*cp == '+')
 101                         if (format == NULL)
 102                                 format = cp + 1;
 103                         else {
 104                                 fprintf(stderr,
 105 _("date: error: multiple formats in command line\n"));
 106                                 usage();
 107                         }
 108                 else {
 109                   fprintf(stderr, _("date: unknown operand: %s\n"), cp);
 110                   usage();
 111                 }
 112         }
 113
 114         display(format, t);
 115         return retval;
 116 }
 117
 118 static void
 119 dogmt(void)
 120 {
 121         static char **  fakeenv;
 122
 123         if (fakeenv == NULL) {
 124                 register int    from;
 125                 register int    to;
 126                 register int    n;
 127                 static char     tzegmt0[] = "TZ=GMT0";
 128
 129                 for (n = 0;  environ[n] != NULL;  ++n)
 130                         continue;
 131                 fakeenv = malloc((n + 2) * sizeof *fakeenv);
 132                 if (fakeenv == NULL) {
 133                         perror(_("Memory exhausted"));
 134                         errensure();
 135                         exit(retval);
 136                 }
 137                 to = 0;
 138                 fakeenv[to++] = tzegmt0;
 139                 for (from = 1; environ[from] != NULL; ++from)
 140                         if (strncmp(environ[from], "TZ=", 3) != 0)
 141                                 fakeenv[to++] = environ[from];
 142                 fakeenv[to] = NULL;
 143                 environ = fakeenv;
 144         }
 145 }
 146
 147 static void
 148 errensure(void)
 149 {
 150         if (retval == EXIT_SUCCESS)
 151                 retval = EXIT_FAILURE;
 152 }
 153
 154 static void
 155 usage(void)
 156 {
 157         fprintf(stderr,
 158                        _("date: usage: date [-u] [-c] [-r seconds]"
 159                          " [+format]\n"));
 160         errensure();
 161         exit(retval);
 162 }
 163
 164 static void
 165 display(char const *format, time_t now)
 166 {
 167         struct tm *tmp;
 168
 169         tmp = localtime(&now);
 170         if (!tmp) {
 171                 fprintf(stderr,
 172                         _("date: error: time out of range\n"));
 173                 errensure();
 174                 return;
 175         }
 176         timeout(stdout, format ? format : "%+", tmp);
 177         putchar('\n');
 178         fflush(stdout);
 179         fflush(stderr);
 180         if (ferror(stdout) || ferror(stderr)) {
 181                 fprintf(stderr,
 182                         _("date: error: couldn't write results\n"));
 183                 errensure();
 184         }
 185 }
 186
 187 #define INCR    1024
 188
 189 static void
 190 timeout(FILE *fp, char const *format, struct tm const *tmp)
 191 {
 192         char *  cp;
 193         size_t  result;
 194         size_t  size;
 195         struct tm tm;
 196
 197         if (*format == '\0')
 198                 return;
 199         if (!tmp) {
 200                 fprintf(stderr, _("date: error: time out of range\n"));
 201                 errensure();
 202                 return;
 203         }
 204         tm = *tmp;
 205         tmp = &tm;
 206         size = INCR;
 207         cp = malloc(size);
 208         for ( ; ; ) {
 209                 if (cp == NULL) {
 210                         fprintf(stderr,
 211                                 _("date: error: can't get memory\n"));
 212                         errensure();
 213                         exit(retval);
 214                 }
 215                 cp[0] = '\1';
 216                 result = strftime(cp, size, format, tmp);
 217                 if (result != 0 || cp[0] == '\0')
 218                         break;
 219                 size += INCR;
 220                 cp = realloc(cp, size);
 221         }
 222         fwrite(cp, 1, result, fp);
 223         free(cp);
 224 }