win32: Replace stat/lstat

2 files changed, 145 insertions, 1 deletions

diff --git a/include/mingw.h b/include/mingw.h
index ba73c362e..a828bd835 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -207,8 +207,18 @@ NOIMPL(fchmod,int fildes UNUSED_PARAM, mode_t mode UNUSED_PARAM);
 NOIMPL(fchown,int fd UNUSED_PARAM, uid_t uid UNUSED_PARAM, gid_t gid UNUSED_PARAM);
 int mingw_mkdir(const char *path, int mode);
 
+/* Use mingw_lstat() instead of lstat()/stat() and
+ * mingw_fstat() instead of fstat() on Windows.
+ */
+int mingw_lstat(const char *file_name, struct stat *buf);
+int mingw_fstat(int fd, struct stat *buf);
+
 #define mkdir mingw_mkdir
-#define lstat stat
+#define stat(x,y) mingw_lstat(x,y)
+#define lseek _lseeki64
+#define fstat mingw_fstat
+#define lstat mingw_lstat
+#define _stati64 mingw_lstat
 
 /*
  * sys/sysmacros.h
diff --git a/win32/mingw.c b/win32/mingw.c
index cc266462f..e8096b5bc 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -149,6 +149,140 @@ FILE *mingw_fopen (const char *filename, const char *mode)
         return fopen(filename, mode);
 }
 
+static inline time_t filetime_to_time_t(const FILETIME *ft)
+{
+        long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
+        winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+        winTime /= 10000000;             /* Nano to seconds resolution */
+        return (time_t)winTime;
+}
+
+static inline int file_attr_to_st_mode (DWORD attr)
+{
+        int fMode = S_IREAD;
+        if (attr & FILE_ATTRIBUTE_DIRECTORY)
+                fMode |= S_IFDIR;
+        else
+                fMode |= S_IFREG;
+        if (!(attr & FILE_ATTRIBUTE_READONLY))
+                fMode |= S_IWRITE;
+        return fMode;
+}
+
+static inline int get_file_attr(const char *fname, WIN32_FILE_ATTRIBUTE_DATA *fdata)
+{
+        if (GetFileAttributesExA(fname, GetFileExInfoStandard, fdata))
+                return 0;
+
+        switch (GetLastError()) {
+        case ERROR_ACCESS_DENIED:
+        case ERROR_SHARING_VIOLATION:
+        case ERROR_LOCK_VIOLATION:
+        case ERROR_SHARING_BUFFER_EXCEEDED:
+                return EACCES;
+        case ERROR_BUFFER_OVERFLOW:
+                return ENAMETOOLONG;
+        case ERROR_NOT_ENOUGH_MEMORY:
+                return ENOMEM;
+        default:
+                return ENOENT;
+        }
+}
+
+/* We keep the do_lstat code in a separate function to avoid recursion.
+ * When a path ends with a slash, the stat will fail with ENOENT. In
+ * this case, we strip the trailing slashes and stat again.
+ */
+static int do_lstat(const char *file_name, struct stat *buf)
+{
+        WIN32_FILE_ATTRIBUTE_DATA fdata;
+
+        if (!(errno = get_file_attr(file_name, &fdata))) {
+                int len = strlen(file_name);
+
+                buf->st_ino = 0;
+                buf->st_gid = 0;
+                buf->st_uid = 0;
+                buf->st_nlink = 1;
+                buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+                if (len > 4 && !strcmp(file_name+len-4, ".exe"))
+                        buf->st_mode |= S_IEXEC;
+                buf->st_size = fdata.nFileSizeLow |
+                        (((off64_t)fdata.nFileSizeHigh)<<32);
+                buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+                buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+                buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+                buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+                return 0;
+        }
+        return -1;
+}
+
+/* We provide our own lstat/fstat functions, since the provided
+ * lstat/fstat functions are so slow. These stat functions are
+ * tailored for Git's usage (read: fast), and are not meant to be
+ * complete. Note that Git stat()s are redirected to mingw_lstat()
+ * too, since Windows doesn't really handle symlinks that well.
+ */
+int mingw_lstat(const char *file_name, struct stat *buf)
+{
+        int namelen;
+        static char alt_name[PATH_MAX];
+
+        if (!do_lstat(file_name, buf))
+                return 0;
+
+        /* if file_name ended in a '/', Windows returned ENOENT;
+         * try again without trailing slashes
+         */
+        if (errno != ENOENT)
+                return -1;
+
+        namelen = strlen(file_name);
+        if (namelen && file_name[namelen-1] != '/')
+                return -1;
+        while (namelen && file_name[namelen-1] == '/')
+                --namelen;
+        if (!namelen || namelen >= PATH_MAX)
+                return -1;
+
+        memcpy(alt_name, file_name, namelen);
+        alt_name[namelen] = 0;
+        return do_lstat(alt_name, buf);
+}
+
+#undef fstat
+int mingw_fstat(int fd, struct stat *buf)
+{
+        HANDLE fh = (HANDLE)_get_osfhandle(fd);
+        BY_HANDLE_FILE_INFORMATION fdata;
+
+        if (fh == INVALID_HANDLE_VALUE) {
+                errno = EBADF;
+                return -1;
+        }
+        /* direct non-file handles to MS's fstat() */
+        if (GetFileType(fh) != FILE_TYPE_DISK)
+                return _fstati64(fd, buf);
+
+        if (GetFileInformationByHandle(fh, &fdata)) {
+                buf->st_ino = 0;
+                buf->st_gid = 0;
+                buf->st_uid = 0;
+                buf->st_nlink = 1;
+                buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+                buf->st_size = fdata.nFileSizeLow |
+                        (((off64_t)fdata.nFileSizeHigh)<<32);
+                buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+                buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+                buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+                buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+                return 0;
+        }
+        errno = EBADF;
+        return -1;
+}
+
 unsigned int sleep (unsigned int seconds)
 {
         Sleep(seconds*1000);