xemacs-beta: src/fileio.c comparison

comparison src/fileio.c @ 404:2f8bb876ab1d r21-2-32

Import from CVS: tag r21-2-32

author	cvs
date	Mon, 13 Aug 2007 11:16:07 +0200
parents	a86b2b5e0111
children	de805c49cfc1

comparison

equal deleted inserted replaced

-:9f011ab08d48
+:2f8bb876ab1d
 arbitrary limit broke generation of Gnus Incoming* files.
 This implementation is better than what one usually finds in libc.
 --hniksic */
+static unsigned int temp_name_rand;
 DEFUN ("make-temp-name", Fmake_temp_name, 1, 1, 0, /*
-Generate temporary file name starting with PREFIX.
+Generate a temporary file name starting with PREFIX.
 The Emacs process number forms part of the result, so there is no
 danger of generating a name being used by another process.
 In addition, this function makes an attempt to choose a name that
 does not specify an existing file.  To make this work, PREFIX should
 be an absolute file name.
 */
 (prefix))
 {
-static char tbl[64] = {
+static const char tbl[64] =
+{
 'A','B','C','D','E','F','G','H',
 'I','J','K','L','M','N','O','P',
 'Q','R','S','T','U','V','W','X',
 'Y','Z','a','b','c','d','e','f',
 'g','h','i','j','k','l','m','n',
 'o','p','q','r','s','t','u','v',
 'w','x','y','z','0','1','2','3',
-'4','5','6','7','8','9','-','_' };
+'4','5','6','7','8','9','-','_'
-static unsigned count, count_initialized_p;
+};
 Lisp_Object val;
 Bytecount len;
 Bufbyte *p, *data;
-unsigned pid;
 CHECK_STRING (prefix);
 /* I was tempted to apply Fexpand_file_name on PREFIX here, but it's
 a bad idea because:
 memcpy (data, XSTRING_DATA (prefix), len);
 p = data + len;
 /* VAL is created by adding 6 characters to PREFIX.  The first three
 are the PID of this process, in base 64, and the second three are
-incremented if the file already exists.  This ensures 262144
+a pseudo-random number seeded from process startup time.  This
-unique file names per PID per PREFIX.  */
+ensures 262144 unique file names per PID per PREFIX per machine.  */
-pid = (unsigned)getpid ();
+{
-*p++ = tbl[pid & 63], pid >>= 6;
+unsigned int pid = (unsigned int) getpid ();
-*p++ = tbl[pid & 63], pid >>= 6;
+*p++ = tbl[(pid >>  0) & 63];
-*p++ = tbl[pid & 63], pid >>= 6;
+*p++ = tbl[(pid >>  6) & 63];
+*p++ = tbl[(pid >> 12) & 63];
+}
 /* Here we try to minimize useless stat'ing when this function is
 invoked many times successively with the same PREFIX.  We achieve
-this by initializing count to a random value, and incrementing it
+this by using a very pseudo-random number generator to generate
-afterwards.  */
+file names unique to this process, with a very long cycle. */
-if (!count_initialized_p)
-{
-count = (unsigned)time (NULL);
-/* Dumping temacs with a non-zero count_initialized_p wouldn't
-make much sense.  */
-if (NILP (Frunning_temacs_p ()))
-	count_initialized_p = 1;
-}
 while (1)
 {
 struct stat ignored;
-unsigned num = count;
+p[0] = tbl[(temp_name_rand >>  0) & 63];
-p[0] = tbl[num & 63], num >>= 6;
+p[1] = tbl[(temp_name_rand >>  6) & 63];
-p[1] = tbl[num & 63], num >>= 6;
+p[2] = tbl[(temp_name_rand >> 12) & 63];
-p[2] = tbl[num & 63], num >>= 6;
 /* Poor man's congruential RN generator.  Replace with ++count
 for debugging.  */
-count += 25229;
+temp_name_rand += 25229;
-count %= 225307;
+temp_name_rand %= 225307;
 QUIT;
 if (stat ((const char *) data, &ignored) < 0)
 	{
 if (XSTRING_LENGTH (dirname_) > (Bytecount) (sizeof (dir) - 1))
 {
 return Fsignal (Qfile_error,
 		      list3 (build_translated_string ("Creating directory"),
-			     build_translated_string ("pathame too long"),
+			     build_translated_string ("pathname too long"),
 			     dirname_));
 }
 strncpy (dir, (char *) XSTRING_DATA (dirname_),
 	   XSTRING_LENGTH (dirname_) + 1);
 UNGCPRO;
 return Qnil;
 }
-#ifdef S_IFLNK
 DEFUN ("make-symbolic-link", Fmake_symbolic_link, 2, 3,
 "FMake symbolic link to file: \nFMake symbolic link to file %s: \np", /*
 Make a symbolic link to FILENAME, named LINKNAME.  Both args strings.
 Signals a `file-already-exists' error if a file LINKNAME already exists
 unless optional third argument OK-IF-ALREADY-EXISTS is non-nil.
 This happens for interactive use with M-x.
 */
 (filename, linkname, ok_if_already_exists))
 {
 /* This function can GC.  GC checked 1997.06.04. */
+/* XEmacs change: run handlers even if local machine doesn't have symlinks */
 Lisp_Object handler;
 struct gcpro gcpro1, gcpro2;
 GCPRO2 (filename, linkname);
 CHECK_STRING (filename);
 handler = Ffind_file_name_handler (linkname, Qmake_symbolic_link);
 if (!NILP (handler))
 RETURN_UNGCPRO (call4 (handler, Qmake_symbolic_link, filename,
 			   linkname, ok_if_already_exists));
+#ifdef S_IFLNK
 if (NILP (ok_if_already_exists)
 || INTP (ok_if_already_exists))
 barf_or_query_if_file_exists (linkname, "make it a link",
 				  INTP (ok_if_already_exists), 0);
 		   (char *) XSTRING_DATA (linkname)))
 {
 report_file_error ("Making symbolic link",
 			 list2 (filename, linkname));
 }
+#endif /* S_IFLNK */
 UNGCPRO;
 return Qnil;
 }
-#endif /* S_IFLNK */
 #ifdef HPUX_NET
 DEFUN ("sysnetunam", Fsysnetunam, 2, 2, 0, /*
 Open a network connection to PATH using LOGIN as the login string.
 Otherwise returns nil.
 */
 (filename))
 {
 /* This function can GC.  GC checked 1997.04.10. */
+/* XEmacs change: run handlers even if local machine doesn't have symlinks */
 #ifdef S_IFLNK
 char *buf;
 int bufsize;
 int valsize;
 Lisp_Object val;
+#endif
 Lisp_Object handler;
 struct gcpro gcpro1;
 CHECK_STRING (filename);
 filename = Fexpand_file_name (filename, Qnil);
 handler = Ffind_file_name_handler (filename, Qfile_symlink_p);
 UNGCPRO;
 if (!NILP (handler))
 return call2 (handler, Qfile_symlink_p, filename);
+#ifdef S_IFLNK
 bufsize = 100;
 while (1)
 {
 buf = xnew_array_and_zero (char, bufsize);
 valsize = readlink ((char *) XSTRING_DATA (filename),
 DEFSUBR (Fmake_directory_internal);
 DEFSUBR (Fdelete_directory);
 DEFSUBR (Fdelete_file);
 DEFSUBR (Frename_file);
 DEFSUBR (Fadd_name_to_file);
-#ifdef S_IFLNK
 DEFSUBR (Fmake_symbolic_link);
-#endif /* S_IFLNK */
 #ifdef HPUX_NET
 DEFSUBR (Fsysnetunam);
 #endif /* HPUX_NET */
 DEFSUBR (Ffile_name_absolute_p);
 DEFSUBR (Ffile_exists_p);
 what the normal separator is.
 */ );
 #ifdef WINDOWSNT
 Vdirectory_sep_char = make_char ('\\');
 #else
 Vdirectory_sep_char = make_char ('/');
 #endif
-}
+reinit_vars_of_fileio ();
+}
+void
+reinit_vars_of_fileio (void)
+{
+/* We want temp_name_rand to be initialized to a value likely to be
+unique to the process, not to the executable.  The danger is that
+two different XEmacs processes using the same binary on different
+machines creating temp files in the same directory will be
+unlucky enough to have the same pid.  If we randomize using
+process startup time, then in practice they will be unlikely to
+collide. We use the microseconds field so that scripts that start
+simultaneous XEmacs processes on multiple machines will have less
+chance of collision.  */
+{
+EMACS_TIME thyme;
+EMACS_GET_TIME (thyme);
+temp_name_rand = (unsigned int) (EMACS_SECS (thyme) ^ EMACS_USECS (thyme));
+}
+}

Mercurial > hg > xemacs-beta

comparison src/fileio.c @ 404:2f8bb876ab1d r21-2-32