statinfo.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2
   3 #include "git-compat-util.h"
   4 #include "environment.h"
   5 #include "statinfo.h"
   6
   7 /*
   8  * Munge st_size into an unsigned int.
   9  */
  10 static unsigned int munge_st_size(off_t st_size) {
  11         unsigned int sd_size = st_size;
  12
  13         /*
  14          * If the file is an exact multiple of 4 GiB, modify the value so it
  15          * doesn't get marked as racily clean (zero).
  16          */
  17         if (!sd_size && st_size)
  18                 return 0x80000000;
  19         else
  20                 return sd_size;
  21 }
  22
  23 void fill_stat_data(struct stat_data *sd, struct stat *st)
  24 {
  25         sd->sd_ctime.sec = (unsigned int)st->st_ctime;
  26         sd->sd_mtime.sec = (unsigned int)st->st_mtime;
  27         sd->sd_ctime.nsec = ST_CTIME_NSEC(*st);
  28         sd->sd_mtime.nsec = ST_MTIME_NSEC(*st);
  29         sd->sd_dev = st->st_dev;
  30         sd->sd_ino = st->st_ino;
  31         sd->sd_uid = st->st_uid;
  32         sd->sd_gid = st->st_gid;
  33         sd->sd_size = munge_st_size(st->st_size);
  34 }
  35
  36 static void set_times(struct stat *st, const struct stat_data *sd)
  37 {
  38         st->st_ctime = sd->sd_ctime.sec;
  39         st->st_mtime = sd->sd_mtime.sec;
  40 #ifdef NO_NSEC
  41         ; /* nothing */
  42 #else
  43 #ifdef USE_ST_TIMESPEC
  44         st->st_ctimespec.tv_nsec = sd->sd_ctime.nsec;
  45         st->st_mtimespec.tv_nsec = sd->sd_mtime.nsec;
  46 #else
  47         st->st_ctim.tv_nsec = sd->sd_ctime.nsec;
  48         st->st_mtim.tv_nsec = sd->sd_mtime.nsec;
  49 #endif
  50 #endif
  51 }
  52
  53 void fake_lstat_data(const struct stat_data *sd, struct stat *st)
  54 {
  55         set_times(st, sd);
  56         st->st_dev = sd->sd_dev;
  57         st->st_ino = sd->sd_ino;
  58         st->st_uid = sd->sd_uid;
  59         st->st_gid = sd->sd_gid;
  60         st->st_size = sd->sd_size;
  61 }
  62
  63 int match_stat_data(const struct stat_data *sd, struct stat *st)
  64 {
  65         int changed = 0;
  66
  67         if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
  68                 changed |= MTIME_CHANGED;
  69         if (trust_ctime && check_stat &&
  70             sd->sd_ctime.sec != (unsigned int)st->st_ctime)
  71                 changed |= CTIME_CHANGED;
  72
  73 #ifdef USE_NSEC
  74         if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
  75                 changed |= MTIME_CHANGED;
  76         if (trust_ctime && check_stat &&
  77             sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
  78                 changed |= CTIME_CHANGED;
  79 #endif
  80
  81         if (check_stat) {
  82                 if (sd->sd_uid != (unsigned int) st->st_uid ||
  83                         sd->sd_gid != (unsigned int) st->st_gid)
  84                         changed |= OWNER_CHANGED;
  85                 if (sd->sd_ino != (unsigned int) st->st_ino)
  86                         changed |= INODE_CHANGED;
  87         }
  88
  89 #ifdef USE_STDEV
  90         /*
  91          * st_dev breaks on network filesystems where different
  92          * clients will have different views of what "device"
  93          * the filesystem is on
  94          */
  95         if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
  96                         changed |= INODE_CHANGED;
  97 #endif
  98
  99         if (sd->sd_size != munge_st_size(st->st_size))
 100                 changed |= DATA_CHANGED;
 101
 102         return changed;
 103 }
 104
 105 void stat_validity_clear(struct stat_validity *sv)
 106 {
 107         FREE_AND_NULL(sv->sd);
 108 }
 109
 110 int stat_validity_check(struct stat_validity *sv, const char *path)
 111 {
 112         struct stat st;
 113
 114         if (stat(path, &st) < 0)
 115                 return sv->sd == NULL;
 116         if (!sv->sd)
 117                 return 0;
 118         return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
 119 }
 120
 121 void stat_validity_update(struct stat_validity *sv, int fd)
 122 {
 123         struct stat st;
 124
 125         if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
 126                 stat_validity_clear(sv);
 127         else {
 128                 if (!sv->sd)
 129                         CALLOC_ARRAY(sv->sd, 1);
 130                 fill_stat_data(sv->sd, &st);
 131         }
 132 }