gl/stat-time.h

   1 /* stat-related time functions.
   2
   3    Copyright (C) 2005, 2007, 2009-2023 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #ifndef STAT_TIME_H
  21 #define STAT_TIME_H 1
  22
  23 #include <errno.h>
  24 #include <stdckdint.h>
  25 #include <stddef.h>
  26 #include <sys/stat.h>
  27 #include <time.h>
  28
  29 #ifndef _GL_INLINE_HEADER_BEGIN
  30  #error "Please include config.h first."
  31 #endif
  32 _GL_INLINE_HEADER_BEGIN
  33 #ifndef _GL_STAT_TIME_INLINE
  34 # define _GL_STAT_TIME_INLINE _GL_INLINE
  35 #endif
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 /* STAT_TIMESPEC (ST, ST_XTIM) is the ST_XTIM member for *ST of type
  42    struct timespec, if available.  If not, then STAT_TIMESPEC_NS (ST,
  43    ST_XTIM) is the nanosecond component of the ST_XTIM member for *ST,
  44    if available.  ST_XTIM can be st_atim, st_ctim, st_mtim, or st_birthtim
  45    for access, status change, data modification, or birth (creation)
  46    time respectively.
  47
  48    These macros are private to stat-time.h.  */
  49 #if _GL_WINDOWS_STAT_TIMESPEC || defined HAVE_STRUCT_STAT_ST_ATIM_TV_NSEC
  50 # if _GL_WINDOWS_STAT_TIMESPEC || defined TYPEOF_STRUCT_STAT_ST_ATIM_IS_STRUCT_TIMESPEC
  51 #  define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim)
  52 # else
  53 #  define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.tv_nsec)
  54 # endif
  55 #elif defined HAVE_STRUCT_STAT_ST_ATIMESPEC_TV_NSEC
  56 # define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim##espec)
  57 #elif defined HAVE_STRUCT_STAT_ST_ATIMENSEC
  58 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim##ensec)
  59 #elif defined HAVE_STRUCT_STAT_ST_ATIM_ST__TIM_TV_NSEC
  60 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.st__tim.tv_nsec)
  61 #endif
  62
  63 /* Return the nanosecond component of *ST's access time.  */
  64 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  65 get_stat_atime_ns (struct stat const *st)
  66 {
  67 # if defined STAT_TIMESPEC
  68   return STAT_TIMESPEC (st, st_atim).tv_nsec;
  69 # elif defined STAT_TIMESPEC_NS
  70   return STAT_TIMESPEC_NS (st, st_atim);
  71 # else
  72   return 0;
  73 # endif
  74 }
  75
  76 /* Return the nanosecond component of *ST's status change time.  */
  77 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  78 get_stat_ctime_ns (struct stat const *st)
  79 {
  80 # if defined STAT_TIMESPEC
  81   return STAT_TIMESPEC (st, st_ctim).tv_nsec;
  82 # elif defined STAT_TIMESPEC_NS
  83   return STAT_TIMESPEC_NS (st, st_ctim);
  84 # else
  85   return 0;
  86 # endif
  87 }
  88
  89 /* Return the nanosecond component of *ST's data modification time.  */
  90 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  91 get_stat_mtime_ns (struct stat const *st)
  92 {
  93 # if defined STAT_TIMESPEC
  94   return STAT_TIMESPEC (st, st_mtim).tv_nsec;
  95 # elif defined STAT_TIMESPEC_NS
  96   return STAT_TIMESPEC_NS (st, st_mtim);
  97 # else
  98   return 0;
  99 # endif
 100 }
 101
 102 /* Return the nanosecond component of *ST's birth time.  */
 103 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
 104 get_stat_birthtime_ns (_GL_UNUSED struct stat const *st)
 105 {
 106 # if defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC
 107   return STAT_TIMESPEC (st, st_birthtim).tv_nsec;
 108 # elif defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
 109   return STAT_TIMESPEC_NS (st, st_birthtim);
 110 # else
 111   return 0;
 112 # endif
 113 }
 114
 115 /* Return *ST's access time.  */
 116 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 117 get_stat_atime (struct stat const *st)
 118 {
 119 #ifdef STAT_TIMESPEC
 120   return STAT_TIMESPEC (st, st_atim);
 121 #else
 122   struct timespec t;
 123   t.tv_sec = st->st_atime;
 124   t.tv_nsec = get_stat_atime_ns (st);
 125   return t;
 126 #endif
 127 }
 128
 129 /* Return *ST's status change time.  */
 130 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 131 get_stat_ctime (struct stat const *st)
 132 {
 133 #ifdef STAT_TIMESPEC
 134   return STAT_TIMESPEC (st, st_ctim);
 135 #else
 136   struct timespec t;
 137   t.tv_sec = st->st_ctime;
 138   t.tv_nsec = get_stat_ctime_ns (st);
 139   return t;
 140 #endif
 141 }
 142
 143 /* Return *ST's data modification time.  */
 144 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 145 get_stat_mtime (struct stat const *st)
 146 {
 147 #ifdef STAT_TIMESPEC
 148   return STAT_TIMESPEC (st, st_mtim);
 149 #else
 150   struct timespec t;
 151   t.tv_sec = st->st_mtime;
 152   t.tv_nsec = get_stat_mtime_ns (st);
 153   return t;
 154 #endif
 155 }
 156
 157 /* Return *ST's birth time, if available; otherwise return a value
 158    with tv_sec and tv_nsec both equal to -1.  */
 159 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 160 get_stat_birthtime (_GL_UNUSED struct stat const *st)
 161 {
 162   struct timespec t;
 163
 164 #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \
 165      || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC)
 166   t = STAT_TIMESPEC (st, st_birthtim);
 167 #elif defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
 168   t.tv_sec = st->st_birthtime;
 169   t.tv_nsec = st->st_birthtimensec;
 170 #elif defined _WIN32 && ! defined __CYGWIN__
 171   /* Native Windows platforms (but not Cygwin) put the "file creation
 172      time" in st_ctime (!).  See
 173      <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions>.  */
 174 # if _GL_WINDOWS_STAT_TIMESPEC
 175   t = st->st_ctim;
 176 # else
 177   t.tv_sec = st->st_ctime;
 178   t.tv_nsec = 0;
 179 # endif
 180 #else
 181   /* Birth time is not supported.  */
 182   t.tv_sec = -1;
 183   t.tv_nsec = -1;
 184 #endif
 185
 186 #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \
 187      || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC \
 188      || defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC)
 189   /* FreeBSD and NetBSD sometimes signal the absence of knowledge by
 190      using zero.  Attempt to work around this problem.  Alas, this can
 191      report failure even for valid timestamps.  Also, NetBSD
 192      sometimes returns junk in the birth time fields; work around this
 193      bug if it is detected.  */
 194   if (! (t.tv_sec && 0 <= t.tv_nsec && t.tv_nsec < 1000000000))
 195     {
 196       t.tv_sec = -1;
 197       t.tv_nsec = -1;
 198     }
 199 #endif
 200
 201   return t;
 202 }
 203
 204 /* If a stat-like function returned RESULT, normalize the timestamps
 205    in *ST, in case this platform suffers from the Solaris 11 bug where
 206    tv_nsec might be negative.  Return the adjusted RESULT, setting
 207    errno to EOVERFLOW if normalization overflowed.  This function
 208    is intended to be private to this .h file.  */
 209 _GL_STAT_TIME_INLINE int
 210 stat_time_normalize (int result, _GL_UNUSED struct stat *st)
 211 {
 212 #if defined __sun && defined STAT_TIMESPEC
 213   if (result == 0)
 214     {
 215       long int timespec_hz = 1000000000;
 216       short int const ts_off[] = { offsetof (struct stat, st_atim),
 217                                    offsetof (struct stat, st_mtim),
 218                                    offsetof (struct stat, st_ctim) };
 219       int i;
 220       for (i = 0; i < sizeof ts_off / sizeof *ts_off; i++)
 221         {
 222           struct timespec *ts = (struct timespec *) ((char *) st + ts_off[i]);
 223           long int q = ts->tv_nsec / timespec_hz;
 224           long int r = ts->tv_nsec % timespec_hz;
 225           if (r < 0)
 226             {
 227               r += timespec_hz;
 228               q--;
 229             }
 230           ts->tv_nsec = r;
 231           /* Overflow is possible, as Solaris 11 stat can yield
 232              tv_sec == TYPE_MINIMUM (time_t) && tv_nsec == -1000000000.
 233              INT_ADD_WRAPV is OK, since time_t is signed on Solaris.  */
 234           if (ckd_add (&ts->tv_sec, q, ts->tv_sec))
 235             {
 236               errno = EOVERFLOW;
 237               return -1;
 238             }
 239         }
 240     }
 241 #endif
 242   return result;
 243 }
 244
 245 #ifdef __cplusplus
 246 }
 247 #endif
 248
 249 _GL_INLINE_HEADER_END
 250
 251 #endif