return ret;
}
+/*
+ * Calling CreateFile() using FILE_APPEND_DATA and without FILE_WRITE_DATA
+ * is documented in [1] as opening a writable file handle in append mode.
+ * (It is believed that) this is atomic since it is maintained by the
+ * kernel unlike the O_APPEND flag which is racily maintained by the CRT.
+ *
+ * [1] https://docs.microsoft.com/en-us/windows/desktop/fileio/file-access-rights-constants
+ *
+ * This trick does not appear to work for named pipes. Instead it creates
+ * a named pipe client handle that cannot be written to. Callers should
+ * just use the regular _wopen() for them. (And since client handle gets
+ * bound to a unique server handle, it isn't really an issue.)
+ */
+static int mingw_open_append(wchar_t const *wfilename, int oflags, ...)
+{
+ HANDLE handle;
+ int fd;
+ DWORD create = (oflags & O_CREAT) ? OPEN_ALWAYS : OPEN_EXISTING;
+
+ /* only these flags are supported */
+ if ((oflags & ~O_CREAT) != (O_WRONLY | O_APPEND))
+ return errno = ENOSYS, -1;
+
+ /*
+ * FILE_SHARE_WRITE is required to permit child processes
+ * to append to the file.
+ */
+ handle = CreateFileW(wfilename, FILE_APPEND_DATA,
+ FILE_SHARE_WRITE | FILE_SHARE_READ,
+ NULL, create, FILE_ATTRIBUTE_NORMAL, NULL);
+ if (handle == INVALID_HANDLE_VALUE)
+ return errno = err_win_to_posix(GetLastError()), -1;
+
+ /*
+ * No O_APPEND here, because the CRT uses it only to reset the
+ * file pointer to EOF before each write(); but that is not
+ * necessary (and may lead to races) for a file created with
+ * FILE_APPEND_DATA.
+ */
+ fd = _open_osfhandle((intptr_t)handle, O_BINARY);
+ if (fd < 0)
+ CloseHandle(handle);
+ return fd;
+}
+
+/*
+ * Does the pathname map to the local named pipe filesystem?
+ * That is, does it have a "//./pipe/" prefix?
+ */
+static int is_local_named_pipe_path(const char *filename)
+{
+ return (is_dir_sep(filename[0]) &&
+ is_dir_sep(filename[1]) &&
+ filename[2] == '.' &&
+ is_dir_sep(filename[3]) &&
+ !strncasecmp(filename+4, "pipe", 4) &&
+ is_dir_sep(filename[8]) &&
+ filename[9]);
+}
+
int mingw_open (const char *filename, int oflags, ...)
{
+ typedef int (*open_fn_t)(wchar_t const *wfilename, int oflags, ...);
va_list args;
unsigned mode;
int fd;
wchar_t wfilename[MAX_PATH];
+ open_fn_t open_fn;
va_start(args, oflags);
mode = va_arg(args, int);
if (filename && !strcmp(filename, "/dev/null"))
filename = "nul";
+ if ((oflags & O_APPEND) && !is_local_named_pipe_path(filename))
+ open_fn = mingw_open_append;
+ else
+ open_fn = _wopen;
+
if (xutftowcs_path(wfilename, filename) < 0)
return -1;
- fd = _wopen(wfilename, oflags, mode);
+ fd = open_fn(wfilename, oflags, mode);
if (fd < 0 && (oflags & O_ACCMODE) != O_RDONLY && errno == EACCES) {
DWORD attrs = GetFileAttributesW(wfilename);
* CREATE_ALWAYS flag of CreateFile()).
*/
if (fd < 0 && errno == EACCES)
- fd = _wopen(wfilename, oflags & ~O_CREAT, mode);
+ fd = open_fn(wfilename, oflags & ~O_CREAT, mode);
if (fd >= 0 && set_hidden_flag(wfilename, 1))
warning("could not mark '%s' as hidden.", filename);
}
die_startup();
/* determine size of argv and environ conversion buffer */
- maxlen = wcslen(_wpgmptr);
+ maxlen = wcslen(wargv[0]);
for (i = 1; i < argc; i++)
maxlen = max(maxlen, wcslen(wargv[i]));
for (i = 0; wenv[i]; i++)
buffer = malloc_startup(maxlen);
/* convert command line arguments and environment to UTF-8 */
- __argv[0] = wcstoutfdup_startup(buffer, _wpgmptr, maxlen);
- for (i = 1; i < argc; i++)
+ for (i = 0; i < argc; i++)
__argv[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen);
for (i = 0; wenv[i]; i++)
environ[i] = wcstoutfdup_startup(buffer, wenv[i], maxlen);