os.h

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: os.h,v 12.10 2005/10/31 02:22:24 bostic Exp $
 */

#ifndef _DB_OS_H_
#define _DB_OS_H_

#if defined(__cplusplus)
extern "C" {
#endif

/* Number of times to retry system calls that return EINTR or EBUSY. */
#define DB_RETRY        100

#ifdef __TANDEM
/*
 * OSS Tandem problem: fsync can return a Guardian file system error of 70,
 * which has no symbolic name in OSS.  HP says to retry the fsync. [#12957]
 */
#define RETRY_CHK(op, ret) do {                                         \
        int __retries = DB_RETRY;                                       \
        do {                                                            \
                (ret) = (op);                                           \
        } while ((ret) != 0 && (((ret) = __os_get_errno()) == EAGAIN || \
            (ret) == EBUSY || (ret) == EINTR || (ret) == EIO ||         \
            (ret) == 70) &&                                             \
            --__retries > 0);                                           \
} while (0)
#else
#define RETRY_CHK(op, ret) do {                                         \
        int __retries = DB_RETRY;                                       \
        do {                                                            \
                (ret) = (op);                                           \
        } while ((ret) != 0 && (((ret) = __os_get_errno()) == EAGAIN || \
            (ret) == EBUSY || (ret) == EINTR || (ret) == EIO) &&        \
            --__retries > 0);                                           \
} while (0)
#endif

#define RETRY_CHK_EINTR_ONLY(op, ret) do {                              \
        int __retries = DB_RETRY;                                       \
        do {                                                            \
                (ret) = (op);                                           \
        } while ((ret) != 0 &&                                          \
            (((ret) = __os_get_errno()) == EINTR) && --__retries > 0);  \
} while (0)

/*
 * Flags understood by __os_open.
 */
#define DB_OSO_ABSMODE  0x0001          /* Absolute mode specified. */
#define DB_OSO_CREATE   0x0002          /* POSIX: O_CREAT */
#define DB_OSO_DIRECT   0x0004          /* Don't buffer the file in the OS. */
#define DB_OSO_DSYNC    0x0008          /* POSIX: O_DSYNC. */
#define DB_OSO_EXCL     0x0010          /* POSIX: O_EXCL */
#define DB_OSO_RDONLY   0x0020          /* POSIX: O_RDONLY */
#define DB_OSO_REGION   0x0040          /* Opening a region file. */
#define DB_OSO_SEQ      0x0080          /* Expected sequential access. */
#define DB_OSO_TEMP     0x0100          /* Remove after last close. */
#define DB_OSO_TRUNC    0x0200          /* POSIX: O_TRUNC */

/*
 * Seek options understood by __os_seek.
 */
typedef enum {
        DB_OS_SEEK_CUR,                 /* POSIX: SEEK_CUR */
        DB_OS_SEEK_END,                 /* POSIX: SEEK_END */
        DB_OS_SEEK_SET                  /* POSIX: SEEK_SET */
} DB_OS_SEEK;

/*
 * We group certain seek/write calls into a single function so that we
 * can use pread(2)/pwrite(2) where they're available.
 */
#define DB_IO_READ      1
#define DB_IO_WRITE     2

/* DB filehandle. */
struct __fh_t {
        /*
         * The file-handle mutex is only used to protect the handle/fd
         * across seek and read/write pairs, it does not protect the
         * the reference count, or any other fields in the structure.
         */
        db_mutex_t mtx_fh;              /* Mutex to lock. */

        int     ref;                    /* Reference count. */

#if defined(DB_WIN32)
        HANDLE  handle;         /* Windows/32 file handle. */
#endif
        int     fd;                     /* POSIX file descriptor. */

        char    *name;                  /* File name (ref DB_FH_UNLINK) */

        /*
         * Last seek statistics, used for zero-filling on filesystems
         * that don't support it directly.
         */
        db_pgno_t pgno;
        u_int32_t pgsize;
        u_int32_t offset;

#define DB_FH_NOSYNC    0x01            /* Handle doesn't need to be sync'd. */
#define DB_FH_OPENED    0x02            /* Handle is valid. */
#define DB_FH_UNLINK    0x04            /* Unlink on close */
        u_int8_t flags;
};

/* Standard 600 mode for __db_omode. */
#define OWNER_RW        "rw-------"

#if defined(__cplusplus)
}
#endif

#include "dbinc_auto/os_ext.h"
#endif /* !_DB_OS_H_ */

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