compat/cygwin.c

   1 #define WIN32_LEAN_AND_MEAN
   2 #ifdef CYGWIN_V15_WIN32API
   3 #include "../git-compat-util.h"
   4 #include "win32.h"
   5 #else
   6 #include <sys/stat.h>
   7 #include <sys/errno.h>
   8 #include "win32.h"
   9 #include "../git-compat-util.h"
  10 #endif
  11 #include "../cache.h" /* to read configuration */
  12
  13 static inline void filetime_to_timespec(const FILETIME *ft, struct timespec *ts)
  14 {
  15         long long winTime = ((long long)ft->dwHighDateTime << 32) +
  16                         ft->dwLowDateTime;
  17         winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
  18         /* convert 100-nsecond interval to seconds and nanoseconds */
  19         ts->tv_sec = (time_t)(winTime/10000000);
  20         ts->tv_nsec = (long)(winTime - ts->tv_sec*10000000LL) * 100;
  21 }
  22
  23 #define size_to_blocks(s) (((s)+511)/512)
  24
  25 /* do_stat is a common implementation for cygwin_lstat and cygwin_stat.
  26  *
  27  * To simplify its logic, in the case of cygwin symlinks, this implementation
  28  * falls back to the cygwin version of stat/lstat, which is provided as the
  29  * last argument.
  30  */
  31 static int do_stat(const char *file_name, struct stat *buf, stat_fn_t cygstat)
  32 {
  33         WIN32_FILE_ATTRIBUTE_DATA fdata;
  34
  35         if (file_name[0] == '/')
  36                 return cygstat (file_name, buf);
  37
  38         if (!(errno = get_file_attr(file_name, &fdata))) {
  39                 /*
  40                  * If the system attribute is set and it is not a directory then
  41                  * it could be a symbol link created in the nowinsymlinks mode.
  42                  * Normally, Cygwin works in the winsymlinks mode, so this situation
  43                  * is very unlikely. For the sake of simplicity of our code, let's
  44                  * Cygwin to handle it.
  45                  */
  46                 if ((fdata.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) &&
  47                     !(fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
  48                         return cygstat(file_name, buf);
  49
  50                 /* fill out the stat structure */
  51                 buf->st_dev = buf->st_rdev = 0; /* not used by Git */
  52                 buf->st_ino = 0;
  53                 buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
  54                 buf->st_nlink = 1;
  55                 buf->st_uid = buf->st_gid = 0;
  56 #ifdef __CYGWIN_USE_BIG_TYPES__
  57                 buf->st_size = ((_off64_t)fdata.nFileSizeHigh << 32) +
  58                         fdata.nFileSizeLow;
  59 #else
  60                 buf->st_size = (off_t)fdata.nFileSizeLow;
  61 #endif
  62                 buf->st_blocks = size_to_blocks(buf->st_size);
  63                 filetime_to_timespec(&fdata.ftLastAccessTime, &buf->st_atim);
  64                 filetime_to_timespec(&fdata.ftLastWriteTime, &buf->st_mtim);
  65                 filetime_to_timespec(&fdata.ftCreationTime, &buf->st_ctim);
  66                 return 0;
  67         } else if (errno == ENOENT) {
  68                 /*
  69                  * In the winsymlinks mode (which is the default), Cygwin
  70                  * emulates symbol links using Windows shortcut files. These
  71                  * files are formed by adding .lnk extension. So, if we have
  72                  * not found the specified file name, it could be that it is
  73                  * a symbol link. Let's Cygwin to deal with that.
  74                  */
  75                 return cygstat(file_name, buf);
  76         }
  77         return -1;
  78 }
  79
  80 /* We provide our own lstat/stat functions, since the provided Cygwin versions
  81  * of these functions are too slow. These stat functions are tailored for Git's
  82  * usage, and therefore they are not meant to be complete and correct emulation
  83  * of lstat/stat functionality.
  84  */
  85 static int cygwin_lstat(const char *path, struct stat *buf)
  86 {
  87         return do_stat(path, buf, lstat);
  88 }
  89
  90 static int cygwin_stat(const char *path, struct stat *buf)
  91 {
  92         return do_stat(path, buf, stat);
  93 }
  94
  95
  96 /*
  97  * At start up, we are trying to determine whether Win32 API or cygwin stat
  98  * functions should be used. The choice is determined by core.ignorecygwinfstricks.
  99  * Reading this option is not always possible immediately as git_dir may
 100  * not be set yet. So until it is set, use cygwin lstat/stat functions.
 101  * However, if core.filemode is set, we must use the Cygwin posix
 102  * stat/lstat as the Windows stat functions do not determine posix filemode.
 103  *
 104  * Note that git_cygwin_config() does NOT call git_default_config() and this
 105  * is deliberate.  Many commands read from config to establish initial
 106  * values in variables and later tweak them from elsewhere (e.g. command line).
 107  * init_stat() is called lazily on demand, typically much late in the program,
 108  * and calling git_default_config() from here would break such variables.
 109  */
 110 static int native_stat = 1;
 111 static int core_filemode = 1; /* matches trust_executable_bit default */
 112
 113 static int git_cygwin_config(const char *var, const char *value, void *cb)
 114 {
 115         if (!strcmp(var, "core.ignorecygwinfstricks"))
 116                 native_stat = git_config_bool(var, value);
 117         else if (!strcmp(var, "core.filemode"))
 118                 core_filemode = git_config_bool(var, value);
 119         return 0;
 120 }
 121
 122 static int init_stat(void)
 123 {
 124         if (have_git_dir() && git_config(git_cygwin_config,NULL)) {
 125                 if (!core_filemode && native_stat) {
 126                         cygwin_stat_fn = cygwin_stat;
 127                         cygwin_lstat_fn = cygwin_lstat;
 128                 } else {
 129                         cygwin_stat_fn = stat;
 130                         cygwin_lstat_fn = lstat;
 131                 }
 132                 return 0;
 133         }
 134         return 1;
 135 }
 136
 137 static int cygwin_stat_stub(const char *file_name, struct stat *buf)
 138 {
 139         return (init_stat() ? stat : *cygwin_stat_fn)(file_name, buf);
 140 }
 141
 142 static int cygwin_lstat_stub(const char *file_name, struct stat *buf)
 143 {
 144         return (init_stat() ? lstat : *cygwin_lstat_fn)(file_name, buf);
 145 }
 146
 147 stat_fn_t cygwin_stat_fn = cygwin_stat_stub;
 148 stat_fn_t cygwin_lstat_fn = cygwin_lstat_stub;
 149