src/logfile.h

   1 /* Copyright (c) 2008, 2009
   2  *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
   3  *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
   4  *      Micah Cowan (micah@cowan.name)
   5  *      Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
   6  * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
   7  *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
   8  *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
   9  * Copyright (c) 1987 Oliver Laumann
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 3, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program (see the file COPYING); if not, see
  23  * http://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
  24  * 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
  25  *
  26  ****************************************************************
  27  * $Id$ GNU
  28  */
  29
  30 struct logfile
  31 {
  32   struct logfile *next;
  33   FILE *fp;             /* a hopefully uniq filepointer to the log file */
  34   char *name;           /* the name. used to reopen, when stat fails. */
  35   int opencount;        /* synchronize logfopen() and logfclose() */
  36   int writecount;       /* increments at logfwrite(), counts write() and fflush() */
  37   int flushcount;       /* increments at logfflush(), zeroed at logfwrite() */
  38   struct stat *st;      /* how the file looks like */
  39 };
  40
  41 /*
  42  * open a logfile, The second argument must be NULL, when the named file
  43  * is already a logfile or must be a appropriatly opened file pointer
  44  * otherwise.
  45  * example: l = logfopen(name, islogfile(name) : NULL ? fopen(name, "a"));
  46  */
  47 struct logfile *logfopen __P((char *name, FILE *fp));
  48
  49 /*
  50  * lookup a logfile by name. This is useful, so that we can provide
  51  * logfopen with a nonzero second argument, exactly when needed.
  52  * islogfile(NULL); returns nonzero if there are any open logfiles at all.
  53  */
  54 int islogfile __P((char *name));
  55
  56 /*
  57  * logfclose does free()
  58  */
  59 int logfclose __P((struct logfile *));
  60 int logfwrite __P((struct logfile *, char *, int));
  61
  62 /*
  63  * logfflush should be called periodically. If no argument is passed,
  64  * all logfiles are flushed, else the specified file
  65  * the number of flushed filepointers is returned
  66  */
  67 int logfflush __P((struct logfile *ifany));
  68
  69 /*
  70  * a reopen function may be registered here, in case you want to bring your
  71  * own (more secure open), it may come along with a private data pointer.
  72  * this function is called, whenever logfwrite/logfflush detect that the
  73  * file has been (re)moved, truncated or changed by someone else.
  74  * if you provide NULL as parameter to logreopen_register, the builtin
  75  * reopen function will be reactivated.
  76  */
  77 void logreopen_register __P((int (*fn) __P((char *, int, struct logfile *)) ));
  78
  79 /*
  80  * Your custom reopen function is required to reuse the exact
  81  * filedescriptor.
  82  * See logfile.c for further specs and an example.
  83  *
  84  * lf_move_fd may help you here, if you do not have dup2(2).
  85  * It closes fd and opens wantfd to access whatever fd accessed.
  86  */
  87 int lf_move_fd __P((int fd, int wantfd));