1 /* Convert a string representation of time to a time value.
2 Copyright (C) 1997-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <limits.h>
20 #include <stdio.h>
21 #include <stdio_ext.h>
22 #include <stdlib.h>
23 #include <stdbool.h>
24 #include <string.h>
25 #include <time.h>
26 #include <unistd.h>
27 #include <sys/stat.h>
28 #include <ctype.h>
29 #include <alloca.h>
30
31 #define TM_YEAR_BASE 1900
32
33
34 /* Prototypes for local functions. */
35 static int first_wday (int year, int mon, int wday);
36 static int check_mday (int year, int mon, int mday);
37
38
39 /* Set to one of the following values to indicate an error.
40 1 the DATEMSK environment variable is null or undefined,
41 2 the template file cannot be opened for reading,
42 3 failed to get file status information,
43 4 the template file is not a regular file,
44 5 an error is encountered while reading the template file,
45 6 memory allication failed (not enough memory available),
46 7 there is no line in the template that matches the input,
47 8 invalid input specification Example: February 31 or a time is
48 specified that can not be represented in a time_t (representing
49 the time in seconds since 00:00:00 UTC, January 1, 1970) */
50 int getdate_err;
51
52
53 /* Returns the first weekday WDAY of month MON in the year YEAR. */
54 static int
first_wday(int year,int mon,int wday)55 first_wday (int year, int mon, int wday)
56 {
57 struct tm tm;
58
59 if (wday == INT_MIN)
60 return 1;
61
62 memset (&tm, 0, sizeof (struct tm));
63 tm.tm_year = year;
64 tm.tm_mon = mon;
65 tm.tm_mday = 1;
66 mktime (&tm);
67
68 return (1 + (wday - tm.tm_wday + 7) % 7);
69 }
70
71
72 /* Returns 1 if MDAY is a valid day of the month in month MON of year
73 YEAR, and 0 if it is not. */
74 static int
check_mday(int year,int mon,int mday)75 check_mday (int year, int mon, int mday)
76 {
77 switch (mon)
78 {
79 case 0:
80 case 2:
81 case 4:
82 case 6:
83 case 7:
84 case 9:
85 case 11:
86 if (mday >= 1 && mday <= 31)
87 return 1;
88 break;
89 case 3:
90 case 5:
91 case 8:
92 case 10:
93 if (mday >= 1 && mday <= 30)
94 return 1;
95 break;
96 case 1:
97 if (mday >= 1 && mday <= (__isleap (year) ? 29 : 28))
98 return 1;
99 break;
100 }
101
102 return 0;
103 }
104
105
106 int
__getdate_r(const char * string,struct tm * tp)107 __getdate_r (const char *string, struct tm *tp)
108 {
109 FILE *fp;
110 char *line;
111 size_t len;
112 char *datemsk;
113 char *result = NULL;
114 __time64_t timer;
115 struct tm tm;
116 struct __stat64_t64 st;
117 bool mday_ok = false;
118
119 datemsk = getenv ("DATEMSK");
120 if (datemsk == NULL || *datemsk == '\0')
121 return 1;
122
123 if (__stat64_time64 (datemsk, &st) < 0)
124 return 3;
125
126 if (!S_ISREG (st.st_mode))
127 return 4;
128
129 if (__access (datemsk, R_OK) < 0)
130 return 2;
131
132 /* Open the template file. */
133 fp = fopen (datemsk, "rce");
134 if (fp == NULL)
135 return 2;
136
137 /* No threads reading this stream. */
138 __fsetlocking (fp, FSETLOCKING_BYCALLER);
139
140 /* Skip leading whitespace. */
141 while (isspace (*string))
142 string++;
143
144 size_t inlen, oldlen;
145
146 oldlen = inlen = strlen (string);
147
148 /* Skip trailing whitespace. */
149 while (inlen > 0 && isspace (string[inlen - 1]))
150 inlen--;
151
152 char *instr = NULL;
153
154 if (inlen < oldlen)
155 {
156 bool using_malloc = false;
157
158 if (__libc_use_alloca (inlen + 1))
159 instr = alloca (inlen + 1);
160 else
161 {
162 instr = malloc (inlen + 1);
163 if (instr == NULL)
164 {
165 fclose (fp);
166 return 6;
167 }
168 using_malloc = true;
169 }
170 memcpy (instr, string, inlen);
171 instr[inlen] = '\0';
172 string = instr;
173
174 if (!using_malloc)
175 instr = NULL;
176 }
177
178 line = NULL;
179 len = 0;
180 do
181 {
182 ssize_t n;
183
184 n = __getline (&line, &len, fp);
185 if (n < 0)
186 break;
187 if (line[n - 1] == '\n')
188 line[n - 1] = '\0';
189
190 /* Do the conversion. */
191 tp->tm_year = tp->tm_mon = tp->tm_mday = tp->tm_wday = INT_MIN;
192 tp->tm_hour = tp->tm_sec = tp->tm_min = INT_MIN;
193 tp->tm_isdst = -1;
194 tp->tm_gmtoff = 0;
195 tp->tm_zone = NULL;
196 result = strptime (string, line, tp);
197 if (result && *result == '\0')
198 break;
199 }
200 while (!__feof_unlocked (fp));
201
202 free (instr);
203
204 /* Free the buffer. */
205 free (line);
206
207 /* Check for errors. */
208 if (__ferror_unlocked (fp))
209 {
210 fclose (fp);
211 return 5;
212 }
213
214 /* Close template file. */
215 fclose (fp);
216
217 if (result == NULL || *result != '\0')
218 return 7;
219
220 /* Get current time. */
221 timer = time64_now ();
222 __localtime64_r (&timer, &tm);
223
224 /* If only the weekday is given, today is assumed if the given day
225 is equal to the current day and next week if it is less. */
226 if (tp->tm_wday >= 0 && tp->tm_wday <= 6 && tp->tm_year == INT_MIN
227 && tp->tm_mon == INT_MIN && tp->tm_mday == INT_MIN)
228 {
229 tp->tm_year = tm.tm_year;
230 tp->tm_mon = tm.tm_mon;
231 tp->tm_mday = tm.tm_mday + (tp->tm_wday - tm.tm_wday + 7) % 7;
232 mday_ok = true;
233 }
234
235 /* If only the month is given, the current month is assumed if the
236 given month is equal to the current month and next year if it is
237 less and no year is given (the first day of month is assumed if
238 no day is given. */
239 if (tp->tm_mon >= 0 && tp->tm_mon <= 11 && tp->tm_mday == INT_MIN)
240 {
241 if (tp->tm_year == INT_MIN)
242 tp->tm_year = tm.tm_year + (((tp->tm_mon - tm.tm_mon) < 0) ? 1 : 0);
243 tp->tm_mday = first_wday (tp->tm_year, tp->tm_mon, tp->tm_wday);
244 mday_ok = true;
245 }
246
247 /* If no hour, minute and second are given the current hour, minute
248 and second are assumed. */
249 if (tp->tm_hour == INT_MIN && tp->tm_min == INT_MIN && tp->tm_sec == INT_MIN)
250 {
251 tp->tm_hour = tm.tm_hour;
252 tp->tm_min = tm.tm_min;
253 tp->tm_sec = tm.tm_sec;
254 }
255
256 /* Fill in the gaps. */
257 if (tp->tm_hour == INT_MIN)
258 tp->tm_hour = 0;
259 if (tp->tm_min == INT_MIN)
260 tp->tm_min = 0;
261 if (tp->tm_sec == INT_MIN)
262 tp->tm_sec = 0;
263
264 /* If no date is given, today is assumed if the given hour is
265 greater than the current hour and tomorrow is assumed if
266 it is less. */
267 if (tp->tm_hour >= 0 && tp->tm_hour <= 23
268 && tp->tm_mon == INT_MIN
269 && tp->tm_mday == INT_MIN && tp->tm_wday == INT_MIN)
270 {
271 tp->tm_mon = tm.tm_mon;
272 tp->tm_mday = tm.tm_mday + ((tp->tm_hour - tm.tm_hour) < 0 ? 1 : 0);
273 mday_ok = 1;
274 }
275
276 /* More fillers. */
277 if (tp->tm_year == INT_MIN)
278 tp->tm_year = tm.tm_year;
279 if (tp->tm_mon == INT_MIN)
280 tp->tm_mon = tm.tm_mon;
281
282 /* Check if the day of month is within range, and if the time can be
283 represented in a time_t. We make use of the fact that the mktime
284 call normalizes the struct tm. */
285 if ((!mday_ok && !check_mday (TM_YEAR_BASE + tp->tm_year, tp->tm_mon,
286 tp->tm_mday))
287 || __mktime64 (tp) == (time_t) -1)
288 return 8;
289
290 return 0;
291 }
weak_alias(__getdate_r,getdate_r)292 weak_alias (__getdate_r, getdate_r)
293 libc_hidden_def (__getdate_r)
294
295 struct tm *
296 getdate (const char *string)
297 {
298 /* Buffer returned by getdate. */
299 static struct tm tmbuf;
300 int errval = __getdate_r (string, &tmbuf);
301
302 if (errval != 0)
303 {
304 getdate_err = errval;
305 return NULL;
306 }
307
308 return &tmbuf;
309 }
310