lib/stat-time.h

   1 /* stat-related time functions.
   2
   3    Copyright (C) 2005, 2007, 2009-2017 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU 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 "intprops.h"
  24
  25 #include <errno.h>
  26 #include <stddef.h>
  27 #include <sys/stat.h>
  28 #include <time.h>
  29
  30 #ifndef _GL_INLINE_HEADER_BEGIN
  31  #error "Please include config.h first."
  32 #endif
  33 _GL_INLINE_HEADER_BEGIN
  34 #ifndef _GL_STAT_TIME_INLINE
  35 # define _GL_STAT_TIME_INLINE _GL_INLINE
  36 #endif
  37
  38 #ifdef __cplusplus
  39 extern "C" {
  40 #endif
  41
  42 /* STAT_TIMESPEC (ST, ST_XTIM) is the ST_XTIM member for *ST of type
  43    struct timespec, if available.  If not, then STAT_TIMESPEC_NS (ST,
  44    ST_XTIM) is the nanosecond component of the ST_XTIM member for *ST,
  45    if available.  ST_XTIM can be st_atim, st_ctim, st_mtim, or st_birthtim
  46    for access, status change, data modification, or birth (creation)
  47    time respectively.
  48
  49    These macros are private to stat-time.h.  */
  50 #if _GL_WINDOWS_STAT_TIMESPEC || defined HAVE_STRUCT_STAT_ST_ATIM_TV_NSEC
  51 # if _GL_WINDOWS_STAT_TIMESPEC || defined TYPEOF_STRUCT_STAT_ST_ATIM_IS_STRUCT_TIMESPEC
  52 #  define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim)
  53 # else
  54 #  define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.tv_nsec)
  55 # endif
  56 #elif defined HAVE_STRUCT_STAT_ST_ATIMESPEC_TV_NSEC
  57 # define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim##espec)
  58 #elif defined HAVE_STRUCT_STAT_ST_ATIMENSEC
  59 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim##ensec)
  60 #elif defined HAVE_STRUCT_STAT_ST_ATIM_ST__TIM_TV_NSEC
  61 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.st__tim.tv_nsec)
  62 #endif
  63
  64 /* Return the nanosecond component of *ST's access time.  */
  65 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  66 get_stat_atime_ns (struct stat const *st)
  67 {
  68 # if defined STAT_TIMESPEC
  69   return STAT_TIMESPEC (st, st_atim).tv_nsec;
  70 # elif defined STAT_TIMESPEC_NS
  71   return STAT_TIMESPEC_NS (st, st_atim);
  72 # else
  73   return 0;
  74 # endif
  75 }
  76
  77 /* Return the nanosecond component of *ST's status change time.  */
  78 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  79 get_stat_ctime_ns (struct stat const *st)
  80 {
  81 # if defined STAT_TIMESPEC
  82   return STAT_TIMESPEC (st, st_ctim).tv_nsec;
  83 # elif defined STAT_TIMESPEC_NS
  84   return STAT_TIMESPEC_NS (st, st_ctim);
  85 # else
  86   return 0;
  87 # endif
  88 }
  89
  90 /* Return the nanosecond component of *ST's data modification time.  */
  91 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
  92 get_stat_mtime_ns (struct stat const *st)
  93 {
  94 # if defined STAT_TIMESPEC
  95   return STAT_TIMESPEC (st, st_mtim).tv_nsec;
  96 # elif defined STAT_TIMESPEC_NS
  97   return STAT_TIMESPEC_NS (st, st_mtim);
  98 # else
  99   return 0;
 100 # endif
 101 }
 102
 103 /* Return the nanosecond component of *ST's birth time.  */
 104 _GL_STAT_TIME_INLINE long int _GL_ATTRIBUTE_PURE
 105 get_stat_birthtime_ns (struct stat const *st)
 106 {
 107 # if defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC
 108   return STAT_TIMESPEC (st, st_birthtim).tv_nsec;
 109 # elif defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
 110   return STAT_TIMESPEC_NS (st, st_birthtim);
 111 # else
 112   /* Avoid a "parameter unused" warning.  */
 113   (void) st;
 114   return 0;
 115 # endif
 116 }
 117
 118 /* Return *ST's access time.  */
 119 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 120 get_stat_atime (struct stat const *st)
 121 {
 122 #ifdef STAT_TIMESPEC
 123   return STAT_TIMESPEC (st, st_atim);
 124 #else
 125   struct timespec t;
 126   t.tv_sec = st->st_atime;
 127   t.tv_nsec = get_stat_atime_ns (st);
 128   return t;
 129 #endif
 130 }
 131
 132 /* Return *ST's status change time.  */
 133 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 134 get_stat_ctime (struct stat const *st)
 135 {
 136 #ifdef STAT_TIMESPEC
 137   return STAT_TIMESPEC (st, st_ctim);
 138 #else
 139   struct timespec t;
 140   t.tv_sec = st->st_ctime;
 141   t.tv_nsec = get_stat_ctime_ns (st);
 142   return t;
 143 #endif
 144 }
 145
 146 /* Return *ST's data modification time.  */
 147 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 148 get_stat_mtime (struct stat const *st)
 149 {
 150 #ifdef STAT_TIMESPEC
 151   return STAT_TIMESPEC (st, st_mtim);
 152 #else
 153   struct timespec t;
 154   t.tv_sec = st->st_mtime;
 155   t.tv_nsec = get_stat_mtime_ns (st);
 156   return t;
 157 #endif
 158 }
 159
 160 /* Return *ST's birth time, if available; otherwise return a value
 161    with tv_sec and tv_nsec both equal to -1.  */
 162 _GL_STAT_TIME_INLINE struct timespec _GL_ATTRIBUTE_PURE
 163 get_stat_birthtime (struct stat const *st)
 164 {
 165   struct timespec t;
 166
 167 #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \
 168      || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC)
 169   t = STAT_TIMESPEC (st, st_birthtim);
 170 #elif defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
 171   t.tv_sec = st->st_birthtime;
 172   t.tv_nsec = st->st_birthtimensec;
 173 #elif (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
 174   /* Native Windows platforms (but not Cygwin) put the "file creation
 175      time" in st_ctime (!).  See
 176      <https://msdn.microsoft.com/en-us/library/14h5k7ff(VS.80).aspx>.  */
 177 # if _GL_WINDOWS_STAT_TIMESPEC
 178   t = st->st_ctim;
 179 # else
 180   t.tv_sec = st->st_ctime;
 181   t.tv_nsec = 0;
 182 # endif
 183 #else
 184   /* Birth time is not supported.  */
 185   t.tv_sec = -1;
 186   t.tv_nsec = -1;
 187   /* Avoid a "parameter unused" warning.  */
 188   (void) st;
 189 #endif
 190
 191 #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \
 192      || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC \
 193      || defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC)
 194   /* FreeBSD and NetBSD sometimes signal the absence of knowledge by
 195      using zero.  Attempt to work around this problem.  Alas, this can
 196      report failure even for valid timestamps.  Also, NetBSD
 197      sometimes returns junk in the birth time fields; work around this
 198      bug if it is detected.  */
 199   if (! (t.tv_sec && 0 <= t.tv_nsec && t.tv_nsec < 1000000000))
 200     {
 201       t.tv_sec = -1;
 202       t.tv_nsec = -1;
 203     }
 204 #endif
 205
 206   return t;
 207 }
 208
 209 /* If a stat-like function returned RESULT, normalize the timestamps
 210    in *ST, in case this platform suffers from the Solaris 11 bug where
 211    tv_nsec might be negative.  Return the adjusted RESULT, setting
 212    errno to EOVERFLOW if normalization overflowed.  This function
 213    is intended to be private to this .h file.  */
 214 _GL_STAT_TIME_INLINE int
 215 stat_time_normalize (int result, struct stat *st)
 216 {
 217 #if defined __sun && defined STAT_TIMESPEC
 218   if (result == 0)
 219     {
 220       long int timespec_resolution = 1000000000;
 221       short int const ts_off[] = { offsetof (struct stat, st_atim),
 222                                    offsetof (struct stat, st_mtim),
 223                                    offsetof (struct stat, st_ctim) };
 224       int i;
 225       for (i = 0; i < sizeof ts_off / sizeof *ts_off; i++)
 226         {
 227           struct timespec *ts = (struct timespec *) ((char *) st + ts_off[i]);
 228           long int q = ts->tv_nsec / timespec_resolution;
 229           long int r = ts->tv_nsec % timespec_resolution;
 230           if (r < 0)
 231             {
 232               r += timespec_resolution;
 233               q--;
 234             }
 235           ts->tv_nsec = r;
 236           /* Overflow is possible, as Solaris 11 stat can yield
 237              tv_sec == TYPE_MINIMUM (time_t) && tv_nsec == -1000000000.
 238              INT_ADD_WRAPV is OK, since time_t is signed on Solaris.  */
 239           if (INT_ADD_WRAPV (q, ts->tv_sec, &ts->tv_sec))
 240             {
 241               errno = EOVERFLOW;
 242               return -1;
 243             }
 244         }
 245     }
 246 #endif
 247   return result;
 248 }
 249
 250 #ifdef __cplusplus
 251 }
 252 #endif
 253
 254 _GL_INLINE_HEADER_END
 255
 256 #endif