new module 'utime'

[Bruno Haible]

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  <address@hidden>

        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
address@hidden
+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).
address@hidden
+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.
address@hidden
-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 address@hidden@
+_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 /* address@hidden@_UTIME_H */
 #endif /* address@hidden@_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; \
        } > address@hidden && \
        mv address@hidden $@