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 static void set_times(struct stat *st, const struct stat_data *sd)
  35 {
  36         st->st_ctime = sd->sd_ctime.sec;
  37         st->st_mtime = sd->sd_mtime.sec;
  38 #ifdef NO_NSEC
  39         ; /* nothing */
  40 #else
  41 #ifdef USE_ST_TIMESPEC
  42         st->st_ctimespec.tv_nsec = sd->sd_ctime.nsec;
  43         st->st_mtimespec.tv_nsec = sd->sd_mtime.nsec;
  44 #else
  45         st->st_ctim.tv_nsec = sd->sd_ctime.nsec;
  46         st->st_mtim.tv_nsec = sd->sd_mtime.nsec;
  47 #endif
  48 #endif
  49 }
  50
  51 void fake_lstat_data(const struct stat_data *sd, struct stat *st)
  52 {
  53         set_times(st, sd);
  54         st->st_dev = sd->sd_dev;
  55         st->st_ino = sd->sd_ino;
  56         st->st_uid = sd->sd_uid;
  57         st->st_gid = sd->sd_gid;
  58         st->st_size = sd->sd_size;
  59 }
  60
  61 int match_stat_data(const struct stat_data *sd, struct stat *st)
  62 {
  63         int changed = 0;
  64
  65         if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
  66                 changed |= MTIME_CHANGED;
  67         if (trust_ctime && check_stat &&
  68             sd->sd_ctime.sec != (unsigned int)st->st_ctime)
  69                 changed |= CTIME_CHANGED;
  70
  71 #ifdef USE_NSEC
  72         if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
  73                 changed |= MTIME_CHANGED;
  74         if (trust_ctime && check_stat &&
  75             sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
  76                 changed |= CTIME_CHANGED;
  77 #endif
  78
  79         if (check_stat) {
  80                 if (sd->sd_uid != (unsigned int) st->st_uid ||
  81                         sd->sd_gid != (unsigned int) st->st_gid)
  82                         changed |= OWNER_CHANGED;
  83                 if (sd->sd_ino != (unsigned int) st->st_ino)
  84                         changed |= INODE_CHANGED;
  85         }
  86
  87 #ifdef USE_STDEV
  88         /*
  89          * st_dev breaks on network filesystems where different
  90          * clients will have different views of what "device"
  91          * the filesystem is on
  92          */
  93         if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
  94                         changed |= INODE_CHANGED;
  95 #endif
  96
  97         if (sd->sd_size != munge_st_size(st->st_size))
  98                 changed |= DATA_CHANGED;
  99
 100         return changed;
 101 }
 102
 103 void stat_validity_clear(struct stat_validity *sv)
 104 {
 105         FREE_AND_NULL(sv->sd);
 106 }
 107
 108 int stat_validity_check(struct stat_validity *sv, const char *path)
 109 {
 110         struct stat st;
 111
 112         if (stat(path, &st) < 0)
 113                 return sv->sd == NULL;
 114         if (!sv->sd)
 115                 return 0;
 116         return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
 117 }
 118
 119 void stat_validity_update(struct stat_validity *sv, int fd)
 120 {
 121         struct stat st;
 122
 123         if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
 124                 stat_validity_clear(sv);
 125         else {
 126                 if (!sv->sd)
 127                         CALLOC_ARRAY(sv->sd, 1);
 128                 fill_stat_data(sv->sd, &st);
 129         }
 130 }