diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 5b6cec8deed..3654543919f 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -4376,7 +4376,16 @@ static void WriteControlFile(void) { int fd; - char buffer[PG_CONTROL_SIZE]; /* need not be aligned */ + char buffer[PG_CONTROL_FILE_SIZE]; /* need not be aligned */ + + /* + * Ensure that the size of the pg_control data structure is sane. See the + * comments for these symbols in pg_control.h. + */ + StaticAssertStmt(sizeof(ControlFileData) <= PG_CONTROL_MAX_SAFE_SIZE, + "pg_control is too large for atomic disk writes"); + StaticAssertStmt(sizeof(ControlFileData) <= PG_CONTROL_FILE_SIZE, + "sizeof(ControlFileData) exceeds PG_CONTROL_FILE_SIZE"); /* * Initialize version and compatibility-check fields @@ -4409,16 +4418,13 @@ WriteControlFile(void) FIN_CRC32C(ControlFile->crc); /* - * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the - * excess over sizeof(ControlFileData). This reduces the odds of + * We write out PG_CONTROL_FILE_SIZE bytes into pg_control, zero-padding + * the excess over sizeof(ControlFileData). This reduces the odds of * premature-EOF errors when reading pg_control. We'll still fail when we * check the contents of the file, but hopefully with a more specific * error than "couldn't read pg_control". */ - if (sizeof(ControlFileData) > PG_CONTROL_SIZE) - elog(PANIC, "sizeof(ControlFileData) is larger than PG_CONTROL_SIZE; fix either one"); - - memset(buffer, 0, PG_CONTROL_SIZE); + memset(buffer, 0, PG_CONTROL_FILE_SIZE); memcpy(buffer, ControlFile, sizeof(ControlFileData)); fd = BasicOpenFile(XLOG_CONTROL_FILE, @@ -4432,7 +4438,7 @@ WriteControlFile(void) errno = 0; pgstat_report_wait_start(WAIT_EVENT_CONTROL_FILE_WRITE); - if (write(fd, buffer, PG_CONTROL_SIZE) != PG_CONTROL_SIZE) + if (write(fd, buffer, PG_CONTROL_FILE_SIZE) != PG_CONTROL_FILE_SIZE) { /* if write didn't set errno, assume problem is no disk space */ if (errno == 0) |