about summary refs log tree commit diff
path: root/time/getdate.c
blob: 6e2f75566bd1b0bb65d4a867524b7b0c79aceadf (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/* Convert a string representation of time to a time value.
   Copyright (C) 1997-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <limits.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>
#include <ctype.h>
#include <alloca.h>

#define TM_YEAR_BASE 1900


/* Prototypes for local functions.  */
static int first_wday (int year, int mon, int wday);
static int check_mday (int year, int mon, int mday);


/* Set to one of the following values to indicate an error.
     1  the DATEMSK environment variable is null or undefined,
     2  the template file cannot be opened for reading,
     3  failed to get file status information,
     4  the template file is not a regular file,
     5  an error is encountered while reading the template file,
     6  memory allication failed (not enough memory available),
     7  there is no line in the template that matches the input,
     8  invalid input specification Example: February 31 or a time is
	specified that can not be represented in a time_t (representing
	the time in seconds since 00:00:00 UTC, January 1, 1970) */
int getdate_err;


/* Returns the first weekday WDAY of month MON in the year YEAR.  */
static int
first_wday (int year, int mon, int wday)
{
  struct tm tm;

  if (wday == INT_MIN)
    return 1;

  memset (&tm, 0, sizeof (struct tm));
  tm.tm_year = year;
  tm.tm_mon = mon;
  tm.tm_mday = 1;
  mktime (&tm);

  return (1 + (wday - tm.tm_wday + 7) % 7);
}


/* Returns 1 if MDAY is a valid day of the month in month MON of year
   YEAR, and 0 if it is not.  */
static int
check_mday (int year, int mon, int mday)
{
  switch (mon)
    {
    case 0:
    case 2:
    case 4:
    case 6:
    case 7:
    case 9:
    case 11:
      if (mday >= 1 && mday <= 31)
	return 1;
      break;
    case 3:
    case 5:
    case 8:
    case 10:
      if (mday >= 1 && mday <= 30)
	return 1;
      break;
    case 1:
      if (mday >= 1 && mday <= (__isleap (year) ? 29 : 28))
	return 1;
      break;
    }

  return 0;
}


int
__getdate_r (const char *string, struct tm *tp)
{
  FILE *fp;
  char *line;
  size_t len;
  char *datemsk;
  char *result = NULL;
  time_t timer;
  struct tm tm;
  struct stat64 st;
  int mday_ok = 0;

  datemsk = getenv ("DATEMSK");
  if (datemsk == NULL || *datemsk == '\0')
    return 1;

  if (__stat64 (datemsk, &st) < 0)
    return 3;

  if (!S_ISREG (st.st_mode))
    return 4;

  if (__access (datemsk, R_OK) < 0)
    return 2;

  /* Open the template file.  */
  fp = fopen (datemsk, "rce");
  if (fp == NULL)
    return 2;

  /* No threads reading this stream.  */
  __fsetlocking (fp, FSETLOCKING_BYCALLER);

  /* Skip leading whitespace.  */
  while (isspace (*string))
    string++;

  size_t inlen, oldlen;

  oldlen = inlen = strlen (string);

  /* Skip trailing whitespace.  */
  while (inlen > 0 && isspace (string[inlen - 1]))
    inlen--;

  char *instr = NULL;

  if (inlen < oldlen)
    {
      bool using_malloc = false;

      if (__libc_use_alloca (inlen + 1))
	instr = alloca (inlen + 1);
      else
	{
	  instr = malloc (inlen + 1);
	  if (instr == NULL)
	    {
	      fclose (fp);
	      return 6;
	    }
	  using_malloc = true;
	}
      memcpy (instr, string, inlen);
      instr[inlen] = '\0';
      string = instr;

      if (!using_malloc)
	instr = NULL;
    }

  line = NULL;
  len = 0;
  do
    {
      ssize_t n;

      n = __getline (&line, &len, fp);
      if (n < 0)
	break;
      if (line[n - 1] == '\n')
	line[n - 1] = '\0';

      /* Do the conversion.  */
      tp->tm_year = tp->tm_mon = tp->tm_mday = tp->tm_wday = INT_MIN;
      tp->tm_hour = tp->tm_sec = tp->tm_min = INT_MIN;
      tp->tm_isdst = -1;
      tp->tm_gmtoff = 0;
      tp->tm_zone = NULL;
      result = strptime (string, line, tp);
      if (result && *result == '\0')
	break;
    }
  while (!__feof_unlocked (fp));

  free (instr);

  /* Free the buffer.  */
  free (line);

  /* Check for errors. */
  if (__ferror_unlocked (fp))
    {
      fclose (fp);
      return 5;
    }

  /* Close template file.  */
  fclose (fp);

  if (result == NULL || *result != '\0')
    return 7;

  /* Get current time.  */
  timer = time_now ();
  __localtime_r (&timer, &tm);

  /* If only the weekday is given, today is assumed if the given day
     is equal to the current day and next week if it is less.  */
  if (tp->tm_wday >= 0 && tp->tm_wday <= 6 && tp->tm_year == INT_MIN
      && tp->tm_mon == INT_MIN && tp->tm_mday == INT_MIN)
    {
      tp->tm_year = tm.tm_year;
      tp->tm_mon = tm.tm_mon;
      tp->tm_mday = tm.tm_mday + (tp->tm_wday - tm.tm_wday + 7) % 7;
      mday_ok = 1;
    }

  /* If only the month is given, the current month is assumed if the
     given month is equal to the current month and next year if it is
     less and no year is given (the first day of month is assumed if
     no day is given.  */
  if (tp->tm_mon >= 0 && tp->tm_mon <= 11 && tp->tm_mday == INT_MIN)
    {
      if (tp->tm_year == INT_MIN)
	tp->tm_year = tm.tm_year + (((tp->tm_mon - tm.tm_mon) < 0) ? 1 : 0);
      tp->tm_mday = first_wday (tp->tm_year, tp->tm_mon, tp->tm_wday);
      mday_ok = 1;
    }

  /* If no hour, minute and second are given the current hour, minute
     and second are assumed.  */
  if (tp->tm_hour == INT_MIN && tp->tm_min == INT_MIN && tp->tm_sec == INT_MIN)
    {
      tp->tm_hour = tm.tm_hour;
      tp->tm_min = tm.tm_min;
      tp->tm_sec = tm.tm_sec;
    }

  /* Fill in the gaps.  */
  if (tp->tm_hour == INT_MIN)
    tp->tm_hour = 0;
  if (tp->tm_min == INT_MIN)
    tp->tm_min = 0;
  if (tp->tm_sec == INT_MIN)
    tp->tm_sec = 0;

  /* If no date is given, today is assumed if the given hour is
     greater than the current hour and tomorrow is assumed if
     it is less.  */
  if (tp->tm_hour >= 0 && tp->tm_hour <= 23
      && tp->tm_mon == INT_MIN
      && tp->tm_mday == INT_MIN && tp->tm_wday == INT_MIN)
    {
      tp->tm_mon = tm.tm_mon;
      tp->tm_mday = tm.tm_mday + ((tp->tm_hour - tm.tm_hour) < 0 ? 1 : 0);
      mday_ok = 1;
    }

  /* More fillers.  */
  if (tp->tm_year == INT_MIN)
    tp->tm_year = tm.tm_year;
  if (tp->tm_mon == INT_MIN)
    tp->tm_mon = tm.tm_mon;

  /* Check if the day of month is within range, and if the time can be
     represented in a time_t.  We make use of the fact that the mktime
     call normalizes the struct tm.  */
  if ((!mday_ok && !check_mday (TM_YEAR_BASE + tp->tm_year, tp->tm_mon,
				tp->tm_mday))
      || mktime (tp) == (time_t) -1)
    return 8;

  return 0;
}
#ifdef weak_alias
weak_alias (__getdate_r, getdate_r)
#endif


struct tm *
getdate (const char *string)
{
  /* Buffer returned by getdate.  */
  static struct tm tmbuf;
  int errval = __getdate_r (string, &tmbuf);

  if (errval != 0)
    {
      getdate_err = errval;
      return NULL;
    }

  return &tmbuf;
}