src/include/postmaster/syslogger.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * syslogger.h
   4  *        Exports from postmaster/syslogger.c.
   5  *
   6  * Copyright (c) 2004-2008, PostgreSQL Global Development Group
   7  *
   8  * $PostgreSQL$
   9  *
  10  *-------------------------------------------------------------------------
  11  */
  12 #ifndef _SYSLOGGER_H
  13 #define _SYSLOGGER_H
  14
  15 #include <limits.h>                             /* for PIPE_BUF */
  16
  17
  18 /*
  19  * Primitive protocol structure for writing to syslogger pipe(s).  The idea
  20  * here is to divide long messages into chunks that are not more than
  21  * PIPE_BUF bytes long, which according to POSIX spec must be written into
  22  * the pipe atomically.  The pipe reader then uses the protocol headers to
  23  * reassemble the parts of a message into a single string.      The reader can
  24  * also cope with non-protocol data coming down the pipe, though we cannot
  25  * guarantee long strings won't get split apart.
  26  *
  27  * We use non-nul bytes in is_last to make the protocol a tiny bit
  28  * more robust against finding a false double nul byte prologue. But
  29  * we still might find it in the len and/or pid bytes unless we're careful.
  30  */
  31
  32 #ifdef PIPE_BUF
  33 /* Are there any systems with PIPE_BUF > 64K?  Unlikely, but ... */
  34 #if PIPE_BUF > 65536
  35 #define PIPE_CHUNK_SIZE  65536
  36 #else
  37 #define PIPE_CHUNK_SIZE  ((int) PIPE_BUF)
  38 #endif
  39 #else                                                   /* not defined */
  40 /* POSIX says the value of PIPE_BUF must be at least 512, so use that */
  41 #define PIPE_CHUNK_SIZE  512
  42 #endif
  43
  44 typedef struct
  45 {
  46         char            nuls[2];                /* always \0\0 */
  47         uint16          len;                    /* size of this chunk (counts data only) */
  48         int32           pid;                    /* writer's pid */
  49         char            is_last;                /* last chunk of message? 't' or 'f' ('T' or
  50                                                                  * 'F' for CSV case) */
  51         char            data[1];                /* data payload starts here */
  52 } PipeProtoHeader;
  53
  54 typedef union
  55 {
  56         PipeProtoHeader proto;
  57         char            filler[PIPE_CHUNK_SIZE];
  58 } PipeProtoChunk;
  59
  60 #define PIPE_HEADER_SIZE  offsetof(PipeProtoHeader, data)
  61 #define PIPE_MAX_PAYLOAD  ((int) (PIPE_CHUNK_SIZE - PIPE_HEADER_SIZE))
  62
  63
  64 /* GUC options */
  65 extern bool Logging_collector;
  66 extern int      Log_RotationAge;
  67 extern int      Log_RotationSize;
  68 extern PGDLLIMPORT char *Log_directory;
  69 extern PGDLLIMPORT char *Log_filename;
  70 extern bool Log_truncate_on_rotation;
  71
  72 extern bool am_syslogger;
  73
  74 #ifndef WIN32
  75 extern int      syslogPipe[2];
  76 #else
  77 extern HANDLE syslogPipe[2];
  78 #endif
  79
  80
  81 extern int      SysLogger_Start(void);
  82
  83 extern void write_syslogger_file(const char *buffer, int count, int dest);
  84
  85 #ifdef EXEC_BACKEND
  86 extern void SysLoggerMain(int argc, char *argv[]);
  87 #endif
  88
  89 #endif   /* _SYSLOGGER_H */