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Annotation of embedaddon/libpdel/sys/logfile.h, revision 1.1.1.1

1.1       misho       1: 
                      2: /*
                      3:  * Copyright (c) 2001-2002 Packet Design, LLC.
                      4:  * All rights reserved.
                      5:  * 
                      6:  * Subject to the following obligations and disclaimer of warranty,
                      7:  * use and redistribution of this software, in source or object code
                      8:  * forms, with or without modifications are expressly permitted by
                      9:  * Packet Design; provided, however, that:
                     10:  * 
                     11:  *    (i)  Any and all reproductions of the source or object code
                     12:  *         must include the copyright notice above and the following
                     13:  *         disclaimer of warranties; and
                     14:  *    (ii) No rights are granted, in any manner or form, to use
                     15:  *         Packet Design trademarks, including the mark "PACKET DESIGN"
                     16:  *         on advertising, endorsements, or otherwise except as such
                     17:  *         appears in the above copyright notice or in the software.
                     18:  * 
                     19:  * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
                     20:  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
                     21:  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
                     22:  * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
                     23:  * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
                     24:  * OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
                     25:  * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
                     26:  * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
                     27:  * RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
                     28:  * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
                     29:  * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
                     30:  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
                     31:  * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
                     32:  * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
                     33:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     34:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
                     35:  * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
                     36:  * THE POSSIBILITY OF SUCH DAMAGE.
                     37:  *
                     38:  * Author: Archie Cobbs <archie@freebsd.org>
                     39:  */
                     40: 
                     41: #ifndef _PDEL_SYS_LOGFILE_H_
                     42: #define _PDEL_SYS_LOGFILE_H_
                     43: 
                     44: /*
                     45:  * Support for on-disk circular log files. Each file contains the
                     46:  * N most recent entries, where an entry is any opaque chunk of
                     47:  * data supplied by the application. New entries overwrite the
                     48:  * oldest entries in a circular fashion.
                     49:  */
                     50: 
                     51: struct logfile;
                     52: 
                     53: __BEGIN_DECLS
                     54: 
                     55: /*
                     56:  * Open/create a new logfile.
                     57:  *
                     58:  * "maxent" sets the maximum number of entries the file can hold.
                     59:  * "maxdata" sets the maximum amount of entry data the file can
                     60:  * hold.
                     61:  *
                     62:  * The size of the file will be approx.: maxdata + (8 * maxent) + 20
                     63:  *
                     64:  * If "path" already exists, it must be a valid logfile and the
                     65:  * "maxent" and "maxdata" arguments are ignored.
                     66:  *
                     67:  * "flags" may be zero, O_SHLOCK or O_EXLOCK.
                     68:  *
                     69:  * If "path" is NULL, a memory-only logfile is created.
                     70:  */
                     71: extern struct  logfile *logfile_open(const char *path,
                     72:                        int flags, u_int32_t maxent, u_int32_t maxdata);
                     73: 
                     74: /*
                     75:  * Close a logfile.
                     76:  */
                     77: extern void    logfile_close(struct logfile **lfp);
                     78: 
                     79: /*
                     80:  * Get the number of valid entries in a logfile.
                     81:  */
                     82: extern u_int32_t logfile_num_entries(struct logfile *lf);
                     83: 
                     84: /*
                     85:  * Retrieve a logfile entry.
                     86:  *
                     87:  * "which" must be a negative number.
                     88:  *
                     89:  * Entry -1 is the most recent, -2 the second most recent, etc.
                     90:  * If "lenp" is not NULL, the length of the entry is returned.
                     91:  */
                     92: extern const   void *logfile_get(struct logfile *lf, int which, int *lenp);
                     93: 
                     94: /*
                     95:  * Add an entry.
                     96:  */
                     97: extern int     logfile_put(struct logfile *lf, const void *data, int len);
                     98: 
                     99: /*
                    100:  * Trim the number of stored entries.
                    101:  */
                    102: extern void    logfile_trim(struct logfile *lf, int num);
                    103: 
                    104: /*
                    105:  * Sync entries to disk.
                    106:  */
                    107: extern void    logfile_sync(struct logfile *lf);
                    108: 
                    109: __END_DECLS
                    110: 
                    111: #endif /* _PDEL_SYS_LOGFILE_H_ */
                    112: