[commit: ghc] master: Change how touchy sets the file time (8c7dc71)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/8c7dc7182803c8e3888e7138958b73ea067fd7e9

>---------------------------------------------------------------

commit 8c7dc7182803c8e3888e7138958b73ea067fd7e9
Author: Ian Lynagh <[email protected]>
Date:   Wed Oct 31 00:53:59 2012 +0100

    Change how touchy sets the file time
    
    Also added a large comment about why we need it

>---------------------------------------------------------------

 utils/touchy/touchy.c |   91 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 86 insertions(+), 5 deletions(-)

diff --git a/utils/touchy/touchy.c b/utils/touchy/touchy.c
index dc4dc8d..93e960d 100644
--- a/utils/touchy/touchy.c
+++ b/utils/touchy/touchy.c
@@ -1,6 +1,5 @@
 /*
- * Simple _utime() wrapper for setting the mod. time on files
- * to the current system time.
+ * Simple 'touch' program for Windows
  *
  */
 #if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(_WIN32)
@@ -12,15 +11,85 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <utime.h>
+#include <windows.h>
+
+/*
+With Windows 7 in a virtual box VM on OS X, some very odd things happen
+with dates and time stamps when SSHing into cygwin. e.g. here the
+"Change" time is in the past:
+
+$ date; touch foo; stat foo
+Fri Dec  2 16:58:07 GMTST 2011
+  File: `foo'
+  Size: 0               Blocks: 0          IO Block: 65536  regular
+empty file
+Device: 540aba0bh/1409989131d   Inode: 562949953592977  Links: 1
+Access: (0644/-rw-r--r--)  Uid: ( 1000/     ian)   Gid: (  513/    None)
+Access: 2011-12-02 16:58:07.414457900 +0000
+Modify: 2011-12-02 16:58:07.414457900 +0000
+Change: 2011-12-02 16:58:03.495141800 +0000
+ Birth: 2011-12-02 16:57:57.731469900 +0000
+
+And if we copy such a file, then the copy is older (as determined by the
+"Modify" time) than the original:
+
+$ date; touch foo; stat foo; cp foo bar; stat bar
+Fri Dec  2 16:59:10 GMTST 2011
+  File: `foo'
+  Size: 0               Blocks: 0          IO Block: 65536  regular
+empty file
+Device: 540aba0bh/1409989131d   Inode: 1407374883725128  Links: 1
+Access: (0644/-rw-r--r--)  Uid: ( 1000/     ian)   Gid: (  513/    None)
+Access: 2011-12-02 16:59:10.118457900 +0000
+Modify: 2011-12-02 16:59:10.118457900 +0000
+Change: 2011-12-02 16:59:06.189477700 +0000
+ Birth: 2011-12-02 16:57:57.731469900 +0000
+  File: `bar'
+  Size: 0               Blocks: 0          IO Block: 65536  regular
+empty file
+Device: 540aba0bh/1409989131d   Inode: 281474976882512  Links: 1
+Access: (0644/-rw-r--r--)  Uid: ( 1000/     ian)   Gid: (  513/    None)
+Access: 2011-12-02 16:59:06.394555800 +0000
+Modify: 2011-12-02 16:59:06.394555800 +0000
+Change: 2011-12-02 16:59:06.395532400 +0000
+ Birth: 2011-12-02 16:58:40.921899600 +0000
+
+This means that make thinks that things are out of date when it
+shouldn't, so reinvokes itself repeatedly until the MAKE_RESTARTS
+infinite-recursion test triggers.
+
+The touchy program, like most other programs, creates files with both
+Modify and Change in the past, which is still a little odd, but is
+consistent, so doesn't break make.
+
+We used to use _utime(argv[i],NULL)) to set the file modification times,
+but after a BST -> GMT change this started giving files a modification
+time an hour in the future:
+
+$ date; utils/touchy/dist/build/tmp/touchy testfile; stat testfile
+Tue, Oct 30, 2012 11:33:06 PM
+  File: `testfile'
+  Size: 0               Blocks: 0          IO Block: 65536  regular empty file
+Device: 540aba0bh/1409989131d   Inode: 9851624184986293  Links: 1
+Access: (0755/-rwxr-xr-x)  Uid: ( 1000/     ian)   Gid: (  513/    None)
+Access: 2012-10-31 00:33:06.000000000 +0000
+Modify: 2012-10-31 00:33:06.000000000 +0000
+Change: 2012-10-30 23:33:06.769118900 +0000
+ Birth: 2012-10-30 23:33:06.769118900 +0000
+
+so now we use the Win32 functions GetSystemTimeAsFileTime and SetFileTime.
+*/
 
 int
 main(int argc, char** argv)
 {
-  int rc;
   int i=0;
   int fd;
   int wBitSet = 0;
   struct _stat sb;
+  FILETIME ft;
+  BOOL b;
+  HANDLE hFile;
 
   if (argc == 1) {
     fprintf(stderr, "Usage: %s <files>\n", argv[0]);
@@ -49,8 +118,20 @@ main(int argc, char** argv)
 	}
 	wBitSet = 1;
     }
-    if ( (rc = _utime(argv[i],NULL)) < 0) {
-      fprintf(stderr, "Unable to change mod. time for %s  (%d)\n", argv[i], errno);
+    hFile = CreateFile(argv[i], GENERIC_WRITE, 0, NULL, OPEN_ALWAYS,
+                       FILE_ATTRIBUTE_NORMAL, NULL);
+    if (hFile == INVALID_HANDLE_VALUE) {
+       fprintf(stderr, "Unable to open %s\n", argv[i]);
+       continue;
+    }
+    GetSystemTimeAsFileTime(&ft);
+    b = SetFileTime(hFile, (LPFILETIME) NULL, (LPFILETIME) NULL, &ft);
+    if (b == 0) {
+      fprintf(stderr, "Unable to change mod. time for %s\n", argv[i]);
+    }
+    b = CloseHandle(hFile);
+    if (b == 0) {
+      fprintf(stderr, "Closing failed for %s\n", argv[i]);
     }
     if (wBitSet) {
 	/* Turn the file back into a read-only file */