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/*-------------------------------------------------------------------------
*
* logtofile_log.c
* Functions to write audit logs to file
*
* Copyright (c) 2020-2025, Francisco Miguel Biete Banon
*
* This code is released under the PostgreSQL licence, as given at
* http://www.postgresql.org/about/licence/
*-------------------------------------------------------------------------
*/
#include "logtofile_log.h"
#include "logtofile_autoclose.h"
#include "logtofile_csv.h"
#include "logtofile_guc.h"
#include "logtofile_json.h"
#include "logtofile_shmem.h"
#include "logtofile_vars.h"
#include <lib/stringinfo.h>
#include <port/atomics.h>
#include <postmaster/syslogger.h>
#include <storage/fd.h>
#include <storage/ipc.h>
#include <storage/lwlock.h>
#include <storage/pg_shmem.h>
#include <utils/timestamp.h>
#include <pthread.h>
#include <sys/stat.h>
/* Defines */
#define PGAUDIT_PREFIX_LINE "AUDIT: "
#define PGAUDIT_PREFIX_LINE_LENGTH sizeof(PGAUDIT_PREFIX_LINE) - 1
#define FORMATTED_TS_LEN 128
/*
* We really want line-buffered mode for logfile output, but Windows does
* not have it, and interprets _IOLBF as _IOFBF (bozos). So use _IONBF
* instead on Windows.
*/
#ifdef WIN32
#define LBF_MODE _IONBF
#else
#define LBF_MODE _IOLBF
#endif
/* variables to use only in this unit */
static char filename_in_use[MAXPGPATH];
static int autoclose_thread_status_debug = 0; // 0: new proc, 1: th running, 2: th running sleep used, 3: th closed
/* forward declaration private functions */
void pgauditlogtofile_close_file(void);
bool pgauditlogtofile_is_enabled(void);
bool pgauditlogtofile_is_open_file(void);
bool pgauditlogtofile_is_prefixed(const char *msg);
bool pgauditlogtofile_open_file(void);
bool pgauditlogtofile_record_audit(const ErrorData *edata, int exclude_nchars);
bool pgauditlogtofile_write_audit(const ErrorData *edata, int exclude_nchars);
/* public methods */
/**
* @brief Hook to emit_log - write the record to the audit or send it to the default logger
* @param edata: error data
* @return void
*/
void PgAuditLogToFile_emit_log(ErrorData *edata)
{
int exclude_nchars = -1;
if (pgauditlogtofile_is_enabled())
{
// printf("ENABLE PRINTF\n");
if (pg_strncasecmp(edata->message, PGAUDIT_PREFIX_LINE, PGAUDIT_PREFIX_LINE_LENGTH) == 0)
{
exclude_nchars = PGAUDIT_PREFIX_LINE_LENGTH;
edata->output_to_server = false;
}
else if (pgauditlogtofile_is_prefixed(edata->message))
{
edata->output_to_server = false;
exclude_nchars = 0;
}
// Scenarios not contemplated above will be ignored
if (exclude_nchars >= 0)
{
if (!pgauditlogtofile_record_audit(edata, exclude_nchars))
{
// ERROR: failed to record in audit, record in server log
edata->output_to_server = true;
}
}
}
if (pgaudit_ltf_prev_emit_log_hook)
pgaudit_ltf_prev_emit_log_hook(edata);
}
/**
* @brief Checks if pgauditlogtofile is completely started and configured
* @param void
* @return bool - true if pgauditlogtofile is enabled
*/
bool pgauditlogtofile_is_enabled(void)
{
if (UsedShmemSegAddr == NULL)
return false;
if (!pgaudit_ltf_shm || !pg_atomic_unlocked_test_flag(&pgaudit_ltf_flag_shutdown) ||
guc_pgaudit_ltf_log_directory == NULL || guc_pgaudit_ltf_log_filename == NULL ||
strlen(guc_pgaudit_ltf_log_directory) == 0 || strlen(guc_pgaudit_ltf_log_filename) == 0)
return false;
return true;
}
/**
* @brief Records an audit log
* @param edata: error data
* @param exclude_nchars: number of characters to exclude from the message
* @return bool - true if the record was written
*/
bool pgauditlogtofile_record_audit(const ErrorData *edata, int exclude_nchars)
{
bool rc;
ereport(DEBUG5, (errmsg("pgauditlogtofile record audit in %s (shm %s)",
filename_in_use, pgaudit_ltf_shm->filename)));
/* do we need to rotate? */
if (strlen(pgaudit_ltf_shm->filename) > 0 && strcmp(filename_in_use, pgaudit_ltf_shm->filename) != 0)
{
ereport(DEBUG3, (
errmsg("pgauditlogtofile record audit file handler requires reopening - shm_filename %s filename_in_use %s",
pgaudit_ltf_shm->filename, filename_in_use)));
pgauditlogtofile_close_file();
}
if (!pgauditlogtofile_is_open_file() && !pgauditlogtofile_open_file())
return false;
rc = pgauditlogtofile_write_audit(edata, exclude_nchars);
pgaudit_ltf_autoclose_active_ts = GetCurrentTimestamp();
if (guc_pgaudit_ltf_auto_close_minutes > 0)
{
// only 1 auto-close thread
if (pg_atomic_test_set_flag(&pgaudit_ltf_autoclose_flag_thread))
{
ereport(DEBUG3, (errmsg("pgauditlogtofile record_audit - create autoclose thread")));
autoclose_thread_status_debug = 1;
pthread_attr_init(&pgaudit_ltf_autoclose_thread_attr);
pthread_attr_setdetachstate(&pgaudit_ltf_autoclose_thread_attr, PTHREAD_CREATE_DETACHED);
pthread_create(&pgaudit_ltf_autoclose_thread, &pgaudit_ltf_autoclose_thread_attr, PgAuditLogToFile_autoclose_run, &autoclose_thread_status_debug);
}
}
return rc;
}
/**
* @brief Close the audit log file
* @param void
* @return void
*/
void pgauditlogtofile_close_file(void)
{
if (pgaudit_ltf_file_handler)
{
fclose(pgaudit_ltf_file_handler);
pgaudit_ltf_file_handler = NULL;
}
}
/**
* @brief Checks if the audit log file is open
* @param void
* @return bool - true if the file is open
*/
bool pgauditlogtofile_is_open_file(void)
{
if (pgaudit_ltf_file_handler)
return true;
else
return false;
}
/**
* @brief Checks if a message starts with one of our intercept prefixes
* @param msg: message
* @return bool - true if the message starts with a prefix
*/
bool pgauditlogtofile_is_prefixed(const char *msg)
{
bool found = false;
size_t i;
if (guc_pgaudit_ltf_log_connections)
{
for (i = 0; !found && i < pgaudit_ltf_shm->num_prefixes_connection; i++)
{
found = pg_strncasecmp(msg, pgaudit_ltf_shm->prefixes_connection[i]->prefix, pgaudit_ltf_shm->prefixes_connection[i]->length) == 0;
}
}
if (!found && guc_pgaudit_ltf_log_disconnections)
{
for (i = 0; !found && i < pgaudit_ltf_shm->num_prefixes_disconnection; i++)
{
found = pg_strncasecmp(msg, pgaudit_ltf_shm->prefixes_disconnection[i]->prefix, pgaudit_ltf_shm->prefixes_disconnection[i]->length) == 0;
}
}
return found;
}
/**
* @brief Open the audit log file
* @param void
* @return bool - true if the file was opened
*/
bool pgauditlogtofile_open_file(void)
{
mode_t oumask;
bool opened = false;
// if the filename is empty, we short-circuit
if (strlen(pgaudit_ltf_shm->filename) == 0)
return opened;
/* Create spool directory if not present; ignore errors */
(void)MakePGDirectory(guc_pgaudit_ltf_log_directory);
/*
* Note we do not let Log_file_mode disable IWUSR, since we certainly want
* to be able to write the files ourselves.
*/
oumask = umask(
(mode_t)((~(Log_file_mode | S_IWUSR)) & (S_IRWXU | S_IRWXG | S_IRWXO)));
pgaudit_ltf_file_handler = fopen(pgaudit_ltf_shm->filename, "a");
umask(oumask);
if (pgaudit_ltf_file_handler)
{
opened = true;
/* 128K buffer and flush on demand or when full -> attempt to use only 1 IO operation per record */
setvbuf(pgaudit_ltf_file_handler, NULL, _IOFBF, 131072);
#ifdef WIN32
/* use CRLF line endings on Windows */
_setmode(_fileno(file_handler), _O_TEXT);
#endif
// File open, we update the filename we are using
strcpy(filename_in_use, pgaudit_ltf_shm->filename);
}
else
{
int save_errno = errno;
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open log file \"%s\": %m", pgaudit_ltf_shm->filename)));
errno = save_errno;
}
return opened;
}
/**
* @brief Writes an audit record in the audit log file
* @param edata: error data
* @param exclude_nchars: number of characters to exclude from the message
*/
bool pgauditlogtofile_write_audit(const ErrorData *edata, int exclude_nchars)
{
StringInfoData buf;
int rc = 0;
initStringInfo(&buf);
/* create the log line */
if (pg_strcasecmp(guc_pgaudit_ltf_log_format, "csv") == 0)
PgAuditLogToFile_csv_audit(&buf, edata, exclude_nchars);
else if (pg_strcasecmp(guc_pgaudit_ltf_log_format, "json") == 0)
PgAuditLogToFile_json_audit(&buf, edata, exclude_nchars);
// auto-close maybe has closed the file
if (!pgaudit_ltf_file_handler)
pgauditlogtofile_open_file();
if (pgaudit_ltf_file_handler)
{
fseek(pgaudit_ltf_file_handler, 0L, SEEK_END);
rc = fwrite(buf.data, 1, buf.len, pgaudit_ltf_file_handler);
pfree(buf.data);
fflush(pgaudit_ltf_file_handler);
}
if (rc != buf.len)
{
int save_errno = errno;
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write audit log file \"%s\": %m", filename_in_use)));
pgauditlogtofile_close_file();
errno = save_errno;
}
return rc == buf.len;
}
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