Viewing file:  syslogger.h (2.78 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*-------------------------------------------------------------------------
*
* syslogger.h
* Exports from postmaster/syslogger.c.
*
* Copyright (c) 2004-2018, PostgreSQL Global Development Group
*
* src/include/postmaster/syslogger.h
*
*-------------------------------------------------------------------------
*/
#ifndef _SYSLOGGER_H
#define _SYSLOGGER_H
#include <limits.h> /* for PIPE_BUF */
/*
* Primitive protocol structure for writing to syslogger pipe(s). The idea
* here is to divide long messages into chunks that are not more than
* PIPE_BUF bytes long, which according to POSIX spec must be written into
* the pipe atomically. The pipe reader then uses the protocol headers to
* reassemble the parts of a message into a single string. The reader can
* also cope with non-protocol data coming down the pipe, though we cannot
* guarantee long strings won't get split apart.
*
* We use non-nul bytes in is_last to make the protocol a tiny bit
* more robust against finding a false double nul byte prologue. But
* we still might find it in the len and/or pid bytes unless we're careful.
*/
#ifdef PIPE_BUF
/* Are there any systems with PIPE_BUF > 64K? Unlikely, but ... */
#if PIPE_BUF > 65536
#define PIPE_CHUNK_SIZE 65536
#else
#define PIPE_CHUNK_SIZE ((int) PIPE_BUF)
#endif
#else /* not defined */
/* POSIX says the value of PIPE_BUF must be at least 512, so use that */
#define PIPE_CHUNK_SIZE 512
#endif
typedef struct
{
char nuls[2]; /* always \0\0 */
uint16 len; /* size of this chunk (counts data only) */
int32 pid; /* writer's pid */
char is_last; /* last chunk of message? 't' or 'f' ('T' or
* 'F' for CSV case) */
char data[FLEXIBLE_ARRAY_MEMBER]; /* data payload starts here */
} PipeProtoHeader;
typedef union
{
PipeProtoHeader proto;
char filler[PIPE_CHUNK_SIZE];
} PipeProtoChunk;
#define PIPE_HEADER_SIZE offsetof(PipeProtoHeader, data)
#define PIPE_MAX_PAYLOAD ((int) (PIPE_CHUNK_SIZE - PIPE_HEADER_SIZE))
/* GUC options */
extern bool Logging_collector;
extern int Log_RotationAge;
extern int Log_RotationSize;
extern PGDLLIMPORT char *Log_directory;
extern PGDLLIMPORT char *Log_filename;
extern bool Log_truncate_on_rotation;
extern int Log_file_mode;
extern bool am_syslogger;
#ifndef WIN32
extern int syslogPipe[2];
#else
extern HANDLE syslogPipe[2];
#endif
extern int SysLogger_Start(void);
extern void write_syslogger_file(const char *buffer, int count, int dest);
#ifdef EXEC_BACKEND
extern void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn();
#endif
/*
* Name of files saving meta-data information about the log
* files currently in use by the syslogger
*/
#define LOG_METAINFO_DATAFILE "current_logfiles"
#define LOG_METAINFO_DATAFILE_TMP LOG_METAINFO_DATAFILE ".tmp"
#endif /* _SYSLOGGER_H */
|