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-rw-r--r--compat/cygwin.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/compat/cygwin.c b/compat/cygwin.c
new file mode 100644
index 0000000000..ebac148392
--- /dev/null
+++ b/compat/cygwin.c
@@ -0,0 +1,143 @@
+#define WIN32_LEAN_AND_MEAN
+#include "../git-compat-util.h"
+#include "win32.h"
+#include "../cache.h" /* to read configuration */
+
+static inline void filetime_to_timespec(const FILETIME *ft, struct timespec *ts)
+{
+ long long winTime = ((long long)ft->dwHighDateTime << 32) +
+ ft->dwLowDateTime;
+ winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+ /* convert 100-nsecond interval to seconds and nanoseconds */
+ ts->tv_sec = (time_t)(winTime/10000000);
+ ts->tv_nsec = (long)(winTime - ts->tv_sec*10000000LL) * 100;
+}
+
+#define size_to_blocks(s) (((s)+511)/512)
+
+/* do_stat is a common implementation for cygwin_lstat and cygwin_stat.
+ *
+ * To simplify its logic, in the case of cygwin symlinks, this implementation
+ * falls back to the cygwin version of stat/lstat, which is provided as the
+ * last argument.
+ */
+static int do_stat(const char *file_name, struct stat *buf, stat_fn_t cygstat)
+{
+ WIN32_FILE_ATTRIBUTE_DATA fdata;
+
+ if (file_name[0] == '/')
+ return cygstat (file_name, buf);
+
+ if (!(errno = get_file_attr(file_name, &fdata))) {
+ /*
+ * If the system attribute is set and it is not a directory then
+ * it could be a symbol link created in the nowinsymlinks mode.
+ * Normally, Cygwin works in the winsymlinks mode, so this situation
+ * is very unlikely. For the sake of simplicity of our code, let's
+ * Cygwin to handle it.
+ */
+ if ((fdata.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) &&
+ !(fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
+ return cygstat(file_name, buf);
+
+ /* fill out the stat structure */
+ buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+ buf->st_ino = 0;
+ buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+ buf->st_nlink = 1;
+ buf->st_uid = buf->st_gid = 0;
+#ifdef __CYGWIN_USE_BIG_TYPES__
+ buf->st_size = ((_off64_t)fdata.nFileSizeHigh << 32) +
+ fdata.nFileSizeLow;
+#else
+ buf->st_size = (off_t)fdata.nFileSizeLow;
+#endif
+ buf->st_blocks = size_to_blocks(buf->st_size);
+ filetime_to_timespec(&fdata.ftLastAccessTime, &buf->st_atim);
+ filetime_to_timespec(&fdata.ftLastWriteTime, &buf->st_mtim);
+ filetime_to_timespec(&fdata.ftCreationTime, &buf->st_ctim);
+ return 0;
+ } else if (errno == ENOENT) {
+ /*
+ * In the winsymlinks mode (which is the default), Cygwin
+ * emulates symbol links using Windows shortcut files. These
+ * files are formed by adding .lnk extension. So, if we have
+ * not found the specified file name, it could be that it is
+ * a symbol link. Let's Cygwin to deal with that.
+ */
+ return cygstat(file_name, buf);
+ }
+ return -1;
+}
+
+/* We provide our own lstat/stat functions, since the provided Cygwin versions
+ * of these functions are too slow. These stat functions are tailored for Git's
+ * usage, and therefore they are not meant to be complete and correct emulation
+ * of lstat/stat functionality.
+ */
+static int cygwin_lstat(const char *path, struct stat *buf)
+{
+ return do_stat(path, buf, lstat);
+}
+
+static int cygwin_stat(const char *path, struct stat *buf)
+{
+ return do_stat(path, buf, stat);
+}
+
+
+/*
+ * At start up, we are trying to determine whether Win32 API or cygwin stat
+ * functions should be used. The choice is determined by core.ignorecygwinfstricks.
+ * Reading this option is not always possible immediately as git_dir may be
+ * not be set yet. So until it is set, use cygwin lstat/stat functions.
+ * However, if core.filemode is set, we must use the Cygwin posix
+ * stat/lstat as the Windows stat fuctions do not determine posix filemode.
+ *
+ * Note that git_cygwin_config() does NOT call git_default_config() and this
+ * is deliberate. Many commands read from config to establish initial
+ * values in variables and later tweak them from elsewhere (e.g. command line).
+ * init_stat() is called lazily on demand, typically much late in the program,
+ * and calling git_default_config() from here would break such variables.
+ */
+static int native_stat = 1;
+static int core_filemode;
+
+static int git_cygwin_config(const char *var, const char *value, void *cb)
+{
+ if (!strcmp(var, "core.ignorecygwinfstricks"))
+ native_stat = git_config_bool(var, value);
+ else if (!strcmp(var, "core.filemode"))
+ core_filemode = git_config_bool(var, value);
+ return 0;
+}
+
+static int init_stat(void)
+{
+ if (have_git_dir()) {
+ git_config(git_cygwin_config, NULL);
+ if (!core_filemode && native_stat) {
+ cygwin_stat_fn = cygwin_stat;
+ cygwin_lstat_fn = cygwin_lstat;
+ } else {
+ cygwin_stat_fn = stat;
+ cygwin_lstat_fn = lstat;
+ }
+ return 0;
+ }
+ return 1;
+}
+
+static int cygwin_stat_stub(const char *file_name, struct stat *buf)
+{
+ return (init_stat() ? stat : *cygwin_stat_fn)(file_name, buf);
+}
+
+static int cygwin_lstat_stub(const char *file_name, struct stat *buf)
+{
+ return (init_stat() ? lstat : *cygwin_lstat_fn)(file_name, buf);
+}
+
+stat_fn_t cygwin_stat_fn = cygwin_stat_stub;
+stat_fn_t cygwin_lstat_fn = cygwin_lstat_stub;
+