diff options
Diffstat (limited to 'storage/bdb/os_win32/os_open.c')
| -rw-r--r-- | storage/bdb/os_win32/os_open.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/storage/bdb/os_win32/os_open.c b/storage/bdb/os_win32/os_open.c new file mode 100644 index 00000000000..c8bae54d585 --- /dev/null +++ b/storage/bdb/os_win32/os_open.c @@ -0,0 +1,217 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1997-2002 + * Sleepycat Software. All rights reserved. + */ + +#include "db_config.h" + +#ifndef lint +static const char revid[] = "$Id: os_open.c,v 11.21 2002/07/12 18:56:55 bostic Exp $"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <fcntl.h> +#include <signal.h> +#include <string.h> +#include <unistd.h> +#endif + +#include "db_int.h" + +/* + * __os_open -- + * Open a file descriptor. + */ +int +__os_open(dbenv, name, flags, mode, fhp) + DB_ENV *dbenv; + const char *name; + u_int32_t flags; + int mode; + DB_FH *fhp; +{ + DWORD bytesWritten; + u_int32_t log_size, pagesize, sectorsize; + int access, attr, oflags, share, createflag; + int ret, nrepeat; + char *drive, dbuf[4]; /* <letter><colon><slosh><nul> */ + +#ifdef DIAGNOSTIC +#define OKFLAGS \ + (DB_OSO_CREATE | DB_OSO_DIRECT | DB_OSO_EXCL | DB_OSO_LOG | \ + DB_OSO_RDONLY | DB_OSO_REGION | DB_OSO_SEQ | DB_OSO_TEMP | \ + DB_OSO_TRUNC) + if ((ret = __db_fchk(dbenv, "__os_open", flags, OKFLAGS)) != 0) + return (ret); +#endif + + /* + * The "public" interface to the __os_open routine passes around POSIX + * 1003.1 flags, not DB flags. If the user has defined their own open + * interface, use the POSIX flags. + */ + if (DB_GLOBAL(j_open) != NULL) { + oflags = O_BINARY | O_NOINHERIT; + + if (LF_ISSET(DB_OSO_CREATE)) + oflags |= O_CREAT; + + if (LF_ISSET(DB_OSO_EXCL)) + oflags |= O_EXCL; + + if (LF_ISSET(DB_OSO_RDONLY)) + oflags |= O_RDONLY; + else + oflags |= O_RDWR; + + if (LF_ISSET(DB_OSO_SEQ)) + oflags |= _O_SEQUENTIAL; + else + oflags |= _O_RANDOM; + + if (LF_ISSET(DB_OSO_TEMP)) + oflags |= _O_TEMPORARY; + + if (LF_ISSET(DB_OSO_TRUNC)) + oflags |= O_TRUNC; + + return (__os_openhandle(dbenv, name, oflags, mode, fhp)); + } + + ret = 0; + + if (LF_ISSET(DB_OSO_LOG)) + log_size = fhp->log_size; /* XXX: Gag. */ + + pagesize = fhp->pagesize; + + memset(fhp, 0, sizeof(*fhp)); + fhp->fd = -1; + + /* + * Otherwise, use the Windows/32 CreateFile interface so that we can + * play magic games with log files to get data flush effects similar + * to the POSIX O_DSYNC flag. + * + * !!! + * We currently ignore the 'mode' argument. It would be possible + * to construct a set of security attributes that we could pass to + * CreateFile that would accurately represents the mode. In worst + * case, this would require looking up user and all group names and + * creating an entry for each. Alternatively, we could call the + * _chmod (partial emulation) function after file creation, although + * this leaves us with an obvious race. However, these efforts are + * largely meaningless on FAT, the most common file system, which + * only has a "readable" and "writeable" flag, applying to all users. + */ + access = GENERIC_READ; + if (!LF_ISSET(DB_OSO_RDONLY)) + access |= GENERIC_WRITE; + + share = FILE_SHARE_READ | FILE_SHARE_WRITE; + attr = FILE_ATTRIBUTE_NORMAL; + + /* + * Reproduce POSIX 1003.1 semantics: if O_CREATE and O_EXCL are both + * specified, fail, returning EEXIST, unless we create the file. + */ + if (LF_ISSET(DB_OSO_CREATE) && LF_ISSET(DB_OSO_EXCL)) + createflag = CREATE_NEW; /* create only if !exist*/ + else if (!LF_ISSET(DB_OSO_CREATE) && LF_ISSET(DB_OSO_TRUNC)) + createflag = TRUNCATE_EXISTING; /* truncate, fail if !exist */ + else if (LF_ISSET(DB_OSO_TRUNC)) + createflag = CREATE_ALWAYS; /* create and truncate */ + else if (LF_ISSET(DB_OSO_CREATE)) + createflag = OPEN_ALWAYS; /* open or create */ + else + createflag = OPEN_EXISTING; /* open only if existing */ + + if (LF_ISSET(DB_OSO_LOG)) { + F_SET(fhp, DB_FH_NOSYNC); + attr |= FILE_FLAG_WRITE_THROUGH; + } + + if (LF_ISSET(DB_OSO_SEQ)) + attr |= FILE_FLAG_SEQUENTIAL_SCAN; + else + attr |= FILE_FLAG_RANDOM_ACCESS; + + if (LF_ISSET(DB_OSO_TEMP)) + attr |= FILE_FLAG_DELETE_ON_CLOSE; + + /* + * We can turn filesystem buffering off if the page size is a + * multiple of the disk's sector size. To find the sector size, + * we call GetDiskFreeSpace, which expects a drive name like "d:\\" + * or NULL for the current disk (i.e., a relative path) + */ + if (LF_ISSET(DB_OSO_DIRECT) && pagesize != 0 && name[0] != '\0') { + if (name[1] == ':') { + drive = dbuf; + snprintf(dbuf, sizeof(dbuf), "%c:\\", name[0]); + } else + drive = NULL; + + if (GetDiskFreeSpace(drive, NULL, §orsize, NULL, NULL) && + pagesize % sectorsize == 0) + attr |= FILE_FLAG_NO_BUFFERING; + } + + for (nrepeat = 1;; ++nrepeat) { + fhp->handle = + CreateFile(name, access, share, NULL, createflag, attr, 0); + if (fhp->handle == INVALID_HANDLE_VALUE) { + /* + * If it's a "temporary" error, we retry up to 3 times, + * waiting up to 12 seconds. While it's not a problem + * if we can't open a database, an inability to open a + * log file is cause for serious dismay. + */ + ret = __os_win32_errno(); + if ((ret != ENFILE && ret != EMFILE && ret != ENOSPC) || + nrepeat > 3) + goto err; + + (void)__os_sleep(dbenv, nrepeat * 2, 0); + } else + break; + } + + /* + * Special handling needed for log files. To get Windows to not update + * the MFT metadata on each write, extend the file to its maximum size. + * Windows will allocate all the data blocks and store them in the MFT + * (inode) area. In addition, flush the MFT area to disk. + * This strategy only works for Win/NT; Win/9X does not + * guarantee that the logs will be zero filled. + */ + if (LF_ISSET(DB_OSO_LOG) && log_size != 0 && __os_is_winnt()) { + if (SetFilePointer(fhp->handle, + log_size - 1, NULL, FILE_BEGIN) == (DWORD)-1) + goto err; + if (WriteFile(fhp->handle, "\x00", 1, &bytesWritten, NULL) == 0) + goto err; + if (bytesWritten != 1) + goto err; + if (SetEndOfFile(fhp->handle) == 0) + goto err; + if (SetFilePointer( + fhp->handle, 0, NULL, FILE_BEGIN) == (DWORD)-1) + goto err; + if (FlushFileBuffers(fhp->handle) == 0) + goto err; + } + + F_SET(fhp, DB_FH_VALID); + return (0); + +err: if (ret == 0) + ret = __os_win32_errno(); + if (fhp->handle != INVALID_HANDLE_VALUE) + (void)CloseHandle(fhp->handle); + return (ret); +} |