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
10 USE_DATE(NEWTOY(date, "d:D:r:u[!dr]", TOYFLAG_BIN))
11
12 config 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 these escapes:
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 %s seconds past the Epoch
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
GLOBALS(char * file;char * setfmt;char * showdate;char * tz;unsigned nano;)50 GLOBALS(
51 char *file;
52 char *setfmt;
53 char *showdate;
54
55 char *tz;
56 unsigned nano;
57 )
58
59 // mktime(3) normalizes the struct tm fields, but date(1) shouldn't.
60 static time_t chkmktime(struct tm *tm, const char *str, const char* fmt)
61 {
62 struct tm tm0 = *tm;
63 struct tm tm1;
64 time_t t = mktime(tm);
65
66 if (t == -1 || !localtime_r(&t, &tm1) ||
67 tm0.tm_sec != tm1.tm_sec || tm0.tm_min != tm1.tm_min ||
68 tm0.tm_hour != tm1.tm_hour || tm0.tm_mday != tm1.tm_mday ||
69 tm0.tm_mon != tm1.tm_mon) {
70 int len;
71
72 strftime(toybuf, sizeof(toybuf), fmt, &tm0);
73 len = strlen(toybuf) + 1;
74 strftime(toybuf + len, sizeof(toybuf) - len, fmt, &tm1);
75 error_exit("bad date '%s'; %s != %s", str, toybuf, toybuf + len);
76 }
77 return t;
78 }
79
utzset(void)80 static void utzset(void)
81 {
82 if (!(TT.tz = getenv("TZ"))) TT.tz = (char *)1;
83 setenv("TZ", "UTC", 1);
84 tzset();
85 }
86
utzreset(void)87 static void utzreset(void)
88 {
89 if (TT.tz) {
90 if (TT.tz != (char *)1) setenv("TZ", TT.tz, 1);
91 else unsetenv("TZ");
92 tzset();
93 }
94 }
95
96 // Handle default posix date format (mmddhhmm[[cc]yy]) or @UNIX[.FRAC]
97 // returns 0 success, nonzero for error
parse_default(char * str,struct tm * tm)98 static int parse_default(char *str, struct tm *tm)
99 {
100 int len = 0;
101
102 // Parse @UNIXTIME[.FRACTION]
103 if (*str == '@') {
104 long long ll;
105 time_t tt;
106
107 // Collect seconds and nanoseconds
108 // Note: struct tm hasn't got a fractional seconds field, thus strptime()
109 // doesn't support it, so store nanoseconds out of band (in globals).
110 // tt and ll are separate because we can't guarantee time_t is 64 bit (yet).
111 sscanf(str, "@%lld%n", &ll, &len);
112 if (str[len]=='.') {
113 str += len+1;
114 for (len = 0; len<9; len++) {
115 TT.nano *= 10;
116 if (isdigit(str[len])) TT.nano += str[len]-'0';
117 }
118 }
119 if (str[len]) return 1;
120 tt = ll;
121 gmtime_r(&tt, tm);
122
123 return 0;
124 }
125
126 // Posix format
127 sscanf(str, "%2u%2u%2u%2u%n", &tm->tm_mon, &tm->tm_mday, &tm->tm_hour,
128 &tm->tm_min, &len);
129 if (len != 8) return 1;
130 str += len;
131 tm->tm_mon--;
132
133 // If year specified, overwrite one we fetched earlier
134 if (*str && *str != '.') {
135 unsigned year;
136
137 len = 0;
138 sscanf(str, "%u%n", &year, &len);
139 if (len == 4) tm->tm_year = year - 1900;
140 else if (len != 2) return 1;
141 str += len;
142
143 // 2 digit years, next 50 years are "future", last 50 years are "past".
144 // A "future" date in past is a century ahead.
145 // A non-future date in the future is a century behind.
146 if (len == 2) {
147 unsigned r1 = tm->tm_year % 100, r2 = (tm->tm_year + 50) % 100,
148 century = tm->tm_year - r1;
149
150 if ((r1 < r2) ? (r1 < year && year < r2) : (year < r1 || year > r2)) {
151 if (year < r1) year += 100;
152 } else if (year > r1) year -= 100;
153 tm->tm_year = year + century;
154 }
155 }
156 if (*str == '.') {
157 len = 0;
158 sscanf(str, ".%u%n", &tm->tm_sec, &len);
159 str += len;
160 } else tm->tm_sec = 0;
161
162 return *str;
163 }
164
date_main(void)165 void date_main(void)
166 {
167 char *setdate = *toys.optargs, *format_string = "%a %b %e %H:%M:%S %Z %Y";
168 struct tm tm;
169
170 memset(&tm, 0, sizeof(struct tm));
171
172 // We can't just pass a timezone to mktime because posix.
173 if (toys.optflags & FLAG_u) utzset();
174
175 if (TT.showdate) {
176 if (TT.setfmt) {
177 char *s = strptime(TT.showdate, TT.setfmt+(*TT.setfmt=='+'), &tm);
178
179 if (!s || *s) goto bad_showdate;
180 } else if (parse_default(TT.showdate, &tm)) goto bad_showdate;
181 } else {
182 time_t now;
183
184 if (TT.file) {
185 struct stat st;
186
187 xstat(TT.file, &st);
188 now = st.st_mtim.tv_sec;
189 } else now = time(0);
190
191 ((toys.optflags & FLAG_u) ? gmtime_r : localtime_r)(&now, &tm);
192 }
193
194 // Fall through if no arguments
195 if (!setdate);
196 // Display the date?
197 else if (*setdate == '+') {
198 format_string = toys.optargs[0]+1;
199 setdate = toys.optargs[1];
200
201 // Set the date
202 } else if (setdate) {
203 struct timeval tv;
204
205 if (parse_default(setdate, &tm)) error_exit("bad date '%s'", setdate);
206
207 if (toys.optflags & FLAG_u) {
208 // We can't just pass a timezone to mktime because posix.
209 utzset();
210 tv.tv_sec = chkmktime(&tm, setdate, format_string);
211 utzreset();
212 } else tv.tv_sec = chkmktime(&tm, setdate, format_string);
213
214 tv.tv_usec = TT.nano/1000;
215 if (settimeofday(&tv, NULL) < 0) perror_msg("cannot set date");
216 }
217
218 utzreset();
219 if (!strftime(toybuf, sizeof(toybuf), format_string, &tm))
220 perror_exit("bad format '%s'", format_string);
221 puts(toybuf);
222
223 return;
224
225 bad_showdate:
226 error_exit("bad date '%s'", TT.showdate);
227 }
228