new module 'utime'

Bruno Haible

2017-04-30 17:35:57 UTC

This patch add a module 'utime'. The original _utime function on native Windows
has a behaviour that depends on the time zone, which is nonsense (see
https://lists.gnu.org/archive/html/bug-gnulib/2017-04/msg00164.html ).

2017-04-29 Bruno Haible <***@clisp.org>

utime: New module.
* lib/utime.in.h: Add comment for snippets.
(utime): New declaration.
* lib/utime.c: New file.
* m4/utime.m4: New file.
* m4/utime_h.m4 (gl_UTIME_H): Test for utime declaration.
(gl_UTIME_H_DEFAULTS): Initialize GNULIB_UTIME, HAVE_UTIME,
REPLACE_UTIME.
* modules/utime-h (Depends-on): Add snippets.
(Makefile.am): Substitute GNULIB_UTIME, HAVE_UTIME, REPLACE_UTIME.
Insert snippets.
* modules/utime: New file.
* doc/posix-functions/utime.texi: Mention the new module.

diff --git a/doc/posix-functions/utime.texi b/doc/posix-functions/utime.texi
index 9cfe373..a77e614 100644
--- a/doc/posix-functions/utime.texi
+++ b/doc/posix-functions/utime.texi
@@ -4,10 +4,18 @@

POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/utime.html}

-Gnulib module: ---
+Gnulib module: utime

Portability problems fixed by Gnulib:
@itemize
+@item
+The times that are set on the file are affected by the current time zone and
+by the DST flag of the current time zone on some platforms:
+mingw, MSVC 14 (when the environment variable @code{TZ} is set).
+@item
+On some platforms, the prototype for @code{utime} omits @code{const}
+for the second argument:
+mingw, MSVC 9.
@end itemize

Portability problems not fixed by Gnulib:
@@ -22,9 +30,4 @@ Solaris 9.
This function cannot set full timestamp resolution. Use
@code{utimensat(AT_FDCWD,file,times,0)}, or the gnulib module utimens,
instead.
-@item
-On some platforms, the prototype for @code{utime} omits @code{const}
-for the second argument. Fortunately, the argument is not modified,
-so it is safe to cast away const:
-mingw, MSVC 9.
@end itemize
diff --git a/lib/utime.c b/lib/utime.c
new file mode 100644
index 0000000..ac5c78b
--- /dev/null
+++ b/lib/utime.c
@@ -0,0 +1,240 @@
+/* Work around platform bugs in utime.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible. */
+
+#include <config.h>
+
+/* Specification. */
+#include <utime.h>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
+# include <errno.h>
+# include <stdbool.h>
+# include <windows.h>
+# include "filename.h"
+# include "malloca.h"
+
+int
+utime (const char *name, const struct utimbuf *ts)
+{
+ /* POSIX <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13>
+ specifies: "More than two leading <slash> characters shall be treated as
+ a single <slash> character." */
+ if (ISSLASH (name[0]) && ISSLASH (name[1]) && ISSLASH (name[2]))
+ {
+ name += 2;
+ while (ISSLASH (name[1]))
+ name++;
+ }
+
+ size_t len = strlen (name);
+ size_t drive_prefix_len = (HAS_DEVICE (name) ? 2 : 0);
+
+ /* Remove trailing slashes (except the very first one, at position
+ drive_prefix_len), but remember their presence. */
+ size_t rlen;
+ bool check_dir = false;
+
+ rlen = len;
+ while (rlen > drive_prefix_len && ISSLASH (name[rlen-1]))
+ {
+ check_dir = true;
+ if (rlen == drive_prefix_len + 1)
+ break;
+ rlen--;
+ }
+
+ const char *rname;
+ char *malloca_rname;
+ if (rlen == len)
+ {
+ rname = name;
+ malloca_rname = NULL;
+ }
+ else
+ {
+ malloca_rname = malloca (rlen + 1);
+ if (malloca_rname == NULL)
+ {
+ errno = ENOMEM;
+ return -1;
+ }
+ memcpy (malloca_rname, name, rlen);
+ malloca_rname[rlen] = '\0';
+ rname = malloca_rname;
+ }
+
+ DWORD error;
+
+ /* Open a handle to the file.
+ CreateFile
+ <https://msdn.microsoft.com/en-us/library/aa363858.aspx>
+ <https://msdn.microsoft.com/en-us/library/aa363874.aspx> */
+ HANDLE handle =
+ CreateFile (rname,
+ FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES,
+ FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+ NULL,
+ OPEN_EXISTING,
+ /* FILE_FLAG_POSIX_SEMANTICS (treat file names that differ only
+ in case as different) makes sense only when applied to *all*
+ filesystem operations. */
+ FILE_FLAG_BACKUP_SEMANTICS /* | FILE_FLAG_POSIX_SEMANTICS */,
+ NULL);
+ if (handle == INVALID_HANDLE_VALUE)
+ {
+ error = GetLastError ();
+ goto failed;
+ }
+
+ if (check_dir)
+ {
+ /* GetFileAttributes
+ <https://msdn.microsoft.com/en-us/library/aa364944.aspx> */
+ DWORD attributes = GetFileAttributes (rname);
+ if (attributes == INVALID_FILE_ATTRIBUTES)
+ {
+ error = GetLastError ();
+ CloseHandle (handle);
+ goto failed;
+ }
+ if ((attributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
+ {
+ CloseHandle (handle);
+ if (malloca_rname != NULL)
+ freea (malloca_rname);
+ errno = ENOTDIR;
+ return -1;
+ }
+ }
+
+ {
+ /* Use SetFileTime(). See
+ <https://msdn.microsoft.com/en-us/library/ms724933.aspx>
+ <https://msdn.microsoft.com/en-us/library/ms724284.aspx> */
+ FILETIME last_access_time;
+ FILETIME last_write_time;
+ if (ts == NULL)
+ {
+ /* GetSystemTimeAsFileTime is the same as
+ GetSystemTime followed by SystemTimeToFileTime.
+ <https://msdn.microsoft.com/en-us/library/ms724397.aspx>.
+ It would be overkill to use
+ GetSystemTimePreciseAsFileTime
+ <https://msdn.microsoft.com/en-us/library/hh706895.aspx>. */
+ FILETIME current_time;
+ GetSystemTimeAsFileTime (&current_time);
+ last_access_time = current_time;
+ last_write_time = current_time;
+ }
+ else
+ {
+ {
+ ULONGLONG time_since_16010101 =
+ (ULONGLONG) ts->actime * 10000000 + 116444736000000000LL;
+ last_access_time.dwLowDateTime = (DWORD) time_since_16010101;
+ last_access_time.dwHighDateTime = time_since_16010101 >> 32;
+ }
+ {
+ ULONGLONG time_since_16010101 =
+ (ULONGLONG) ts->modtime * 10000000 + 116444736000000000LL;
+ last_write_time.dwLowDateTime = (DWORD) time_since_16010101;
+ last_write_time.dwHighDateTime = time_since_16010101 >> 32;
+ }
+ }
+ if (SetFileTime (handle, NULL, &last_access_time, &last_write_time))
+ {
+ CloseHandle (handle);
+ if (malloca_rname != NULL)
+ freea (malloca_rname);
+ return 0;
+ }
+ else
+ {
+ #if 0
+ DWORD sft_error = GetLastError ();
+ fprintf (stderr, "utime SetFileTime error 0x%x\n", (unsigned int) sft_error);
+ #endif
+ CloseHandle (handle);
+ if (malloca_rname != NULL)
+ freea (malloca_rname);
+ errno = EINVAL;
+ return -1;
+ }
+ }
+
+ failed:
+ {
+ #if 0
+ fprintf (stderr, "utime CreateFile/GetFileAttributes error 0x%x\n", (unsigned int) error);
+ #endif
+ if (malloca_rname != NULL)
+ freea (malloca_rname);
+
+ switch (error)
+ {
+ /* Some of these errors probably cannot happen with the specific flags
+ that we pass to CreateFile. But who knows... */
+ case ERROR_FILE_NOT_FOUND: /* The last component of rname does not exist. */
+ case ERROR_PATH_NOT_FOUND: /* Some directory component in rname does not exist. */
+ case ERROR_BAD_PATHNAME: /* rname is such as '\\server'. */
+ case ERROR_BAD_NET_NAME: /* rname is such as '\\server\nonexistentshare'. */
+ case ERROR_INVALID_NAME: /* rname contains wildcards, misplaced colon, etc. */
+ case ERROR_DIRECTORY:
+ errno = ENOENT;
+ break;
+
+ case ERROR_ACCESS_DENIED: /* rname is such as 'C:\System Volume Information\foo'. */
+ case ERROR_SHARING_VIOLATION: /* rname is such as 'C:\pagefile.sys'. */
+ /* XXX map to EACCESS or EPERM? */
+ errno = (ts != NULL ? EPERM : EACCES);
+ break;
+
+ case ERROR_OUTOFMEMORY:
+ errno = ENOMEM;
+ break;
+
+ case ERROR_WRITE_PROTECT:
+ errno = EROFS;
+ break;
+
+ case ERROR_WRITE_FAULT:
+ case ERROR_READ_FAULT:
+ case ERROR_GEN_FAILURE:
+ errno = EIO;
+ break;
+
+ case ERROR_BUFFER_OVERFLOW:
+ case ERROR_FILENAME_EXCED_RANGE:
+ errno = ENAMETOOLONG;
+ break;
+
+ case ERROR_DELETE_PENDING: /* XXX map to EACCESS or EPERM? */
+ errno = EPERM;
+ break;
+
+ default:
+ errno = EINVAL;
+ break;
+ }
+
+ return -1;
+ }
+}
+
+#endif
diff --git a/lib/utime.in.h b/lib/utime.in.h
index 26a1cea..8847e72 100644
--- a/lib/utime.in.h
+++ b/lib/utime.in.h
@@ -33,6 +33,13 @@
# include <sys/utime.h>
#endif

+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here. */
+
+/* The definition of _GL_ARG_NONNULL is copied here. */
+
+/* The definition of _GL_WARN_ON_USE is copied here. */
+
+
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__

/* Define 'struct utimbuf' as an alias of 'struct _utimbuf'
@@ -41,5 +48,32 @@

#endif

+
+#if @GNULIB_UTIME@
+# if @REPLACE_UTIME@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# define utime rpl_utime
+# endif
+_GL_FUNCDECL_RPL (utime, int, (const char *filename, const struct utimbuf *ts)
+ _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (utime, int, (const char *filename, const struct utimbuf *ts));
+# else
+# if !@HAVE_UTIME@
+_GL_FUNCDECL_SYS (utime, int, (const char *filename, const struct utimbuf *ts)
+ _GL_ARG_NONNULL ((1)));
+# endif
+_GL_CXXALIAS_SYS (utime, int, (const char *filename, const struct utimbuf *ts));
+# endif
+_GL_CXXALIASWARN (utime);
+#elif defined GNULIB_POSIXCHECK
+# undef utime
+# if HAVE_RAW_DECL_UTIME
+_GL_WARN_ON_USE (utime,
+ "utime is unportable - "
+ "use gnulib module canonicalize-lgpl for portability");
+# endif
+#endif
+
+
#endif /* ***@GUARD_PREFIX@_UTIME_H */
#endif /* ***@GUARD_PREFIX@_UTIME_H */
diff --git a/m4/utime.m4 b/m4/utime.m4
new file mode 100644
index 0000000..7d4a603
--- /dev/null
+++ b/m4/utime.m4
@@ -0,0 +1,26 @@
+# utime.m4 serial 1
+dnl Copyright (C) 2017 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_UTIME],
+[
+ AC_REQUIRE([gl_UTIME_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ AC_CHECK_FUNCS_ONCE([utime])
+ if test $ac_cv_func_utime = no; then
+ HAVE_UTIME=0
+ else
+ case "$host_os" in
+ mingw*)
+ dnl On this platform, the original utime() or _utime() produces
+ dnl timestamps that are affected by the time zone.
+ REPLACE_UTIME=1
+ ;;
+ esac
+ fi
+])
+
+# Prerequisites of lib/utime.c.
+AC_DEFUN([gl_PREREQ_UTIME], [:])
diff --git a/m4/utime_h.m4 b/m4/utime_h.m4
index 6b0ac5c..550f764 100644
--- a/m4/utime_h.m4
+++ b/m4/utime_h.m4
@@ -33,6 +33,12 @@ AC_DEFUN([gl_UTIME_H],
fi
AC_SUBST([UTIME_H])
AM_CONDITIONAL([GL_GENERATE_UTIME_H], [test -n "$UTIME_H"])
+
+ dnl Check for declarations of anything we want to poison if the
+ dnl corresponding gnulib module is not in use.
+ gl_WARN_ON_USE_PREPARE([[#include <utime.h>
+ ]],
+ [utime])
])

AC_DEFUN([gl_UTIME_MODULE_INDICATOR],
@@ -46,5 +52,8 @@ AC_DEFUN([gl_UTIME_MODULE_INDICATOR],

AC_DEFUN([gl_UTIME_H_DEFAULTS],
[
+ GNULIB_UTIME=0; AC_SUBST([GNULIB_UTIME])
dnl Assume POSIX behavior unless another module says otherwise.
+ HAVE_UTIME=1; AC_SUBST([HAVE_UTIME])
+ REPLACE_UTIME=0; AC_SUBST([REPLACE_UTIME])
])
diff --git a/modules/utime b/modules/utime
new file mode 100644
index 0000000..545a24c
--- /dev/null
+++ b/modules/utime
@@ -0,0 +1,30 @@
+Description:
+utime() function: set access and modification times of a file.
+
+Files:
+lib/utime.c
+m4/utime.m4
+
+Depends-on:
+utime-h
+filename [test $HAVE_UTIME = 0 || test $REPLACE_UTIME = 1]
+malloca [test $HAVE_UTIME = 0 || test $REPLACE_UTIME = 1]
+
+configure.ac:
+gl_FUNC_UTIME
+if test $HAVE_UTIME = 0 || test $REPLACE_UTIME = 1; then
+ AC_LIBOBJ([utime])
+ gl_PREREQ_UTIME
+fi
+gl_UTIME_MODULE_INDICATOR([utime])
+
+Makefile.am:
+
+Include:
+<utime.h>
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible
diff --git a/modules/utime-h b/modules/utime-h
index 0e02d5b..a60f45a 100644
--- a/modules/utime-h
+++ b/modules/utime-h
@@ -7,6 +7,9 @@ m4/utime_h.m4

Depends-on:
include_next
+snippet/arg-nonnull
+snippet/c++defs
+snippet/warn-on-use

configure.ac:
gl_UTIME_H
@@ -26,6 +29,12 @@ utime.h: utime.in.h $(top_builddir)/config.status
-e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
-e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
-e 's|@''NEXT_UTIME_H''@|$(NEXT_UTIME_H)|g' \
+ -e 's/@''GNULIB_UTIME''@/$(GNULIB_UTIME)/g' \
+ -e 's|@''HAVE_UTIME''@|$(HAVE_UTIME)|g' \
+ -e 's|@''REPLACE_UTIME''@|$(REPLACE_UTIME)|g' \
+ -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+ -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
+ -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
< $(srcdir)/utime.in.h; \
} > $@-t && \
mv $@-t $@