src/logfile.h

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