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173c97812f
The XLOG_CONTROL_FILE macro (defined in access/xlog_internal.h) represents the control file name. While some parts of the codebase already use this macro, others previously hardcoded the file name as a string. This commit replaces those hardcoded strings with the macro, ensuring consistent usage throughout the code. This makes future maintenance easier and improves searchability, for example when grepping for control file usage. Author: Anton A. Melnikov <a.melnikov@postgrespro.ru> Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Masao Fujii <masao.fujii@gmail.com> Discussion: https://postgr.es/m/0841ec77-47e5-452a-adb4-c6fa55d605fc@postgrespro.ru
284 lines
7.1 KiB
C
284 lines
7.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* controldata_utils.c
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* Common code for control data file output.
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*
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*
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/common/controldata_utils.c
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef FRONTEND
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#include "postgres.h"
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#else
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#include "postgres_fe.h"
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#endif
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#include <unistd.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <time.h>
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#include "access/xlog_internal.h"
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#include "catalog/pg_control.h"
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#include "common/controldata_utils.h"
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#ifdef FRONTEND
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#include "common/file_perm.h"
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#include "common/logging.h"
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#endif
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#include "port/pg_crc32c.h"
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#ifndef FRONTEND
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#include "pgstat.h"
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#include "storage/fd.h"
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#endif
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/*
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* get_controlfile()
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*
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* Get controlfile values. The result is returned as a palloc'd copy of the
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* control file data.
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*
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* crc_ok_p can be used by the caller to see whether the CRC of the control
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* file data is correct.
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*/
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ControlFileData *
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get_controlfile(const char *DataDir, bool *crc_ok_p)
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{
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char ControlFilePath[MAXPGPATH];
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snprintf(ControlFilePath, MAXPGPATH, "%s/%s", DataDir, XLOG_CONTROL_FILE);
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return get_controlfile_by_exact_path(ControlFilePath, crc_ok_p);
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}
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/*
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* get_controlfile_by_exact_path()
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*
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* As above, but the caller specifies the path to the control file itself,
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* rather than the path to the data directory.
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*/
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ControlFileData *
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get_controlfile_by_exact_path(const char *ControlFilePath, bool *crc_ok_p)
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{
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ControlFileData *ControlFile;
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int fd;
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pg_crc32c crc;
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int r;
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#ifdef FRONTEND
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pg_crc32c last_crc;
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int retries = 0;
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#endif
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Assert(crc_ok_p);
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ControlFile = palloc_object(ControlFileData);
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#ifdef FRONTEND
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INIT_CRC32C(last_crc);
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retry:
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#endif
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#ifndef FRONTEND
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if ((fd = OpenTransientFile(ControlFilePath, O_RDONLY | PG_BINARY)) == -1)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not open file \"%s\" for reading: %m",
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ControlFilePath)));
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#else
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if ((fd = open(ControlFilePath, O_RDONLY | PG_BINARY, 0)) == -1)
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pg_fatal("could not open file \"%s\" for reading: %m",
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ControlFilePath);
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#endif
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r = read(fd, ControlFile, sizeof(ControlFileData));
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if (r != sizeof(ControlFileData))
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{
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if (r < 0)
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#ifndef FRONTEND
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not read file \"%s\": %m", ControlFilePath)));
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#else
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pg_fatal("could not read file \"%s\": %m", ControlFilePath);
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#endif
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else
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#ifndef FRONTEND
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("could not read file \"%s\": read %d of %zu",
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ControlFilePath, r, sizeof(ControlFileData))));
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#else
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pg_fatal("could not read file \"%s\": read %d of %zu",
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ControlFilePath, r, sizeof(ControlFileData));
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#endif
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}
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#ifndef FRONTEND
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if (CloseTransientFile(fd) != 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not close file \"%s\": %m",
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ControlFilePath)));
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#else
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if (close(fd) != 0)
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pg_fatal("could not close file \"%s\": %m", ControlFilePath);
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#endif
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/* Check the CRC. */
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INIT_CRC32C(crc);
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COMP_CRC32C(crc,
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ControlFile,
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offsetof(ControlFileData, crc));
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FIN_CRC32C(crc);
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*crc_ok_p = EQ_CRC32C(crc, ControlFile->crc);
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#ifdef FRONTEND
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/*
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* If the server was writing at the same time, it is possible that we read
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* partially updated contents on some systems. If the CRC doesn't match,
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* retry a limited number of times until we compute the same bad CRC twice
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* in a row with a short sleep in between. Then the failure is unlikely
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* to be due to a concurrent write.
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*/
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if (!*crc_ok_p &&
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(retries == 0 || !EQ_CRC32C(crc, last_crc)) &&
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retries < 10)
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{
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retries++;
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last_crc = crc;
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pg_usleep(10000);
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goto retry;
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}
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#endif
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/* Make sure the control file is valid byte order. */
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if (ControlFile->pg_control_version % 65536 == 0 &&
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ControlFile->pg_control_version / 65536 != 0)
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#ifndef FRONTEND
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elog(ERROR, _("byte ordering mismatch"));
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#else
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pg_log_warning("possible byte ordering mismatch\n"
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"The byte ordering used to store the pg_control file might not match the one\n"
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"used by this program. In that case the results below would be incorrect, and\n"
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"the PostgreSQL installation would be incompatible with this data directory.");
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#endif
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return ControlFile;
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}
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/*
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* update_controlfile()
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*
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* Update controlfile values with the contents given by caller. The
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* contents to write are included in "ControlFile". "do_sync" can be
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* optionally used to flush the updated control file. Note that it is up
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* to the caller to properly lock ControlFileLock when calling this
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* routine in the backend.
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*/
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void
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update_controlfile(const char *DataDir,
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ControlFileData *ControlFile, bool do_sync)
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{
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int fd;
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char buffer[PG_CONTROL_FILE_SIZE];
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char ControlFilePath[MAXPGPATH];
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/* Update timestamp */
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ControlFile->time = (pg_time_t) time(NULL);
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/* Recalculate CRC of control file */
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INIT_CRC32C(ControlFile->crc);
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COMP_CRC32C(ControlFile->crc,
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ControlFile,
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offsetof(ControlFileData, crc));
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FIN_CRC32C(ControlFile->crc);
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/*
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* Write out PG_CONTROL_FILE_SIZE bytes into pg_control by zero-padding
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* the excess over sizeof(ControlFileData), to avoid premature EOF related
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* errors when reading it.
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*/
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memset(buffer, 0, PG_CONTROL_FILE_SIZE);
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memcpy(buffer, ControlFile, sizeof(ControlFileData));
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snprintf(ControlFilePath, sizeof(ControlFilePath), "%s/%s", DataDir, XLOG_CONTROL_FILE);
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#ifndef FRONTEND
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/*
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* All errors issue a PANIC, so no need to use OpenTransientFile() and to
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* worry about file descriptor leaks.
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*/
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if ((fd = BasicOpenFile(ControlFilePath, O_RDWR | PG_BINARY)) < 0)
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ereport(PANIC,
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(errcode_for_file_access(),
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errmsg("could not open file \"%s\": %m",
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ControlFilePath)));
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#else
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if ((fd = open(ControlFilePath, O_WRONLY | PG_BINARY,
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pg_file_create_mode)) == -1)
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pg_fatal("could not open file \"%s\": %m", ControlFilePath);
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#endif
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errno = 0;
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#ifndef FRONTEND
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pgstat_report_wait_start(WAIT_EVENT_CONTROL_FILE_WRITE_UPDATE);
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#endif
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if (write(fd, buffer, PG_CONTROL_FILE_SIZE) != PG_CONTROL_FILE_SIZE)
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{
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/* if write didn't set errno, assume problem is no disk space */
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if (errno == 0)
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errno = ENOSPC;
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#ifndef FRONTEND
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ereport(PANIC,
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(errcode_for_file_access(),
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errmsg("could not write file \"%s\": %m",
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ControlFilePath)));
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#else
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pg_fatal("could not write file \"%s\": %m", ControlFilePath);
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#endif
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}
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#ifndef FRONTEND
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pgstat_report_wait_end();
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#endif
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if (do_sync)
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{
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#ifndef FRONTEND
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pgstat_report_wait_start(WAIT_EVENT_CONTROL_FILE_SYNC_UPDATE);
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if (pg_fsync(fd) != 0)
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ereport(PANIC,
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(errcode_for_file_access(),
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errmsg("could not fsync file \"%s\": %m",
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ControlFilePath)));
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pgstat_report_wait_end();
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#else
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if (fsync(fd) != 0)
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pg_fatal("could not fsync file \"%s\": %m", ControlFilePath);
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#endif
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}
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if (close(fd) != 0)
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{
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#ifndef FRONTEND
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ereport(PANIC,
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(errcode_for_file_access(),
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errmsg("could not close file \"%s\": %m",
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ControlFilePath)));
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#else
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pg_fatal("could not close file \"%s\": %m", ControlFilePath);
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#endif
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}
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}
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