statinfo.c

   1 #include "git-compat-util.h"
   2 #include "environment.h"
   3 #include "statinfo.h"
   4
   5 /*
   6  * Munge st_size into an unsigned int.
   7  */
   8 static unsigned int munge_st_size(off_t st_size) {
   9         unsigned int sd_size = st_size;
  10
  11         /*
  12          * If the file is an exact multiple of 4 GiB, modify the value so it
  13          * doesn't get marked as racily clean (zero).
  14          */
  15         if (!sd_size && st_size)
  16                 return 0x80000000;
  17         else
  18                 return sd_size;
  19 }
  20
  21 void fill_stat_data(struct stat_data *sd, struct stat *st)
  22 {
  23         sd->sd_ctime.sec = (unsigned int)st->st_ctime;
  24         sd->sd_mtime.sec = (unsigned int)st->st_mtime;
  25         sd->sd_ctime.nsec = ST_CTIME_NSEC(*st);
  26         sd->sd_mtime.nsec = ST_MTIME_NSEC(*st);
  27         sd->sd_dev = st->st_dev;
  28         sd->sd_ino = st->st_ino;
  29         sd->sd_uid = st->st_uid;
  30         sd->sd_gid = st->st_gid;
  31         sd->sd_size = munge_st_size(st->st_size);
  32 }
  33
  34 int match_stat_data(const struct stat_data *sd, struct stat *st)
  35 {
  36         int changed = 0;
  37
  38         if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
  39                 changed |= MTIME_CHANGED;
  40         if (trust_ctime && check_stat &&
  41             sd->sd_ctime.sec != (unsigned int)st->st_ctime)
  42                 changed |= CTIME_CHANGED;
  43
  44 #ifdef USE_NSEC
  45         if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
  46                 changed |= MTIME_CHANGED;
  47         if (trust_ctime && check_stat &&
  48             sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
  49                 changed |= CTIME_CHANGED;
  50 #endif
  51
  52         if (check_stat) {
  53                 if (sd->sd_uid != (unsigned int) st->st_uid ||
  54                         sd->sd_gid != (unsigned int) st->st_gid)
  55                         changed |= OWNER_CHANGED;
  56                 if (sd->sd_ino != (unsigned int) st->st_ino)
  57                         changed |= INODE_CHANGED;
  58         }
  59
  60 #ifdef USE_STDEV
  61         /*
  62          * st_dev breaks on network filesystems where different
  63          * clients will have different views of what "device"
  64          * the filesystem is on
  65          */
  66         if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
  67                         changed |= INODE_CHANGED;
  68 #endif
  69
  70         if (sd->sd_size != munge_st_size(st->st_size))
  71                 changed |= DATA_CHANGED;
  72
  73         return changed;
  74 }
  75
  76 void stat_validity_clear(struct stat_validity *sv)
  77 {
  78         FREE_AND_NULL(sv->sd);
  79 }
  80
  81 int stat_validity_check(struct stat_validity *sv, const char *path)
  82 {
  83         struct stat st;
  84
  85         if (stat(path, &st) < 0)
  86                 return sv->sd == NULL;
  87         if (!sv->sd)
  88                 return 0;
  89         return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
  90 }
  91
  92 void stat_validity_update(struct stat_validity *sv, int fd)
  93 {
  94         struct stat st;
  95
  96         if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
  97                 stat_validity_clear(sv);
  98         else {
  99                 if (!sv->sd)
 100                         CALLOC_ARRAY(sv->sd, 1);
 101                 fill_stat_data(sv->sd, &st);
 102         }
 103 }