foundationdb/fdbrpc/libeio/eio.h

/*
 * libeio API header
 *
 * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libeio@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifndef EIO_H_
#define EIO_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stddef.h>
#include <signal.h>
#include <sys/types.h>
#include "stdio.h"

typedef struct eio_req eio_req;
typedef struct eio_dirent eio_dirent;

typedef int (*eio_cb)(eio_req* req);

#ifndef EIO_REQ_MEMBERS
#define EIO_REQ_MEMBERS
#endif

#ifndef EIO_STRUCT_STAT
#ifdef _WIN32
#define EIO_STRUCT_STAT struct _stati64
#define EIO_STRUCT_STATI64
#else
#define EIO_STRUCT_STAT struct stat
#endif
#endif

#ifdef _WIN32
typedef int eio_uid_t;
typedef int eio_gid_t;
#ifdef __MINGW32__ /* no intptr_t */
typedef ssize_t eio_ssize_t;
#else
typedef intptr_t eio_ssize_t; /* or SSIZE_T */
#endif
#if __GNUC__
typedef long long eio_ino_t; /* signed for compatibility to msvc */
#else
typedef __int64 eio_ino_t; /* unsigned not supported by msvc */
#endif
#else
typedef uid_t eio_uid_t;
typedef gid_t eio_gid_t;
typedef ssize_t eio_ssize_t;
typedef ino_t eio_ino_t;
#endif

#ifndef EIO_STRUCT_STATVFS
#define EIO_STRUCT_STATVFS struct statvfs
#endif

/* managing working directories */

typedef struct eio_pwd* eio_wd;

#define EIO_CWD 0 /* the current working directory of the process, guaranteed to be a null pointer */
#define EIO_INVALID_WD ((eio_wd)(int)-1) /* failure return for eio_wd_open */

eio_wd eio_wd_open_sync(eio_wd wd, const char* path);
void eio_wd_close_sync(eio_wd wd);

/* for readdir */

/* eio_readdir flags */
enum {
	EIO_READDIR_DENTS = 0x01, /* ptr2 contains eio_dirents, not just the (unsorted) names */
	EIO_READDIR_DIRS_FIRST = 0x02, /* dirents gets sorted into a good stat() ing order to find directories first */
	EIO_READDIR_STAT_ORDER = 0x04, /* dirents gets sorted into a good stat() ing order to quickly stat all files */
	EIO_READDIR_FOUND_UNKNOWN = 0x80, /* set by eio_readdir when *_ARRAY was set and any TYPE=UNKNOWN's were found */

	EIO_READDIR_CUSTOM1 = 0x100, /* for use by apps */
	EIO_READDIR_CUSTOM2 = 0x200 /* for use by apps */
};

/* using "typical" values in the hope that the compiler will do something sensible */
enum eio_dtype {
	EIO_DT_UNKNOWN = 0,
	EIO_DT_FIFO = 1,
	EIO_DT_CHR = 2,
	EIO_DT_MPC = 3, /* multiplexed char device (v7+coherent) */
	EIO_DT_DIR = 4,
	EIO_DT_NAM = 5, /* xenix special named file */
	EIO_DT_BLK = 6,
	EIO_DT_MPB = 7, /* multiplexed block device (v7+coherent) */
	EIO_DT_REG = 8,
	EIO_DT_NWK = 9, /* HP-UX network special */
	EIO_DT_CMP = 9, /* VxFS compressed */
	EIO_DT_LNK = 10,
	/*  DT_SHAD    = 11,*/
	EIO_DT_SOCK = 12,
	EIO_DT_DOOR = 13, /* solaris door */
	EIO_DT_WHT = 14,
	EIO_DT_MAX = 15 /* highest DT_VALUE ever, hopefully */
};

struct eio_dirent {
	int nameofs; /* offset of null-terminated name string in (char *)req->ptr2 */
	unsigned short namelen; /* size of filename without trailing 0 */
	unsigned char type; /* one of EIO_DT_* */
	signed char score; /* internal use */
	eio_ino_t inode; /* the inode number, if available, otherwise unspecified */
};

/* eio_msync flags */
enum { EIO_MS_ASYNC = 1, EIO_MS_INVALIDATE = 2, EIO_MS_SYNC = 4 };

/* eio_mtouch flags */
enum { EIO_MT_MODIFY = 1 };

/* eio_sync_file_range flags */
enum { EIO_SYNC_FILE_RANGE_WAIT_BEFORE = 1, EIO_SYNC_FILE_RANGE_WRITE = 2, EIO_SYNC_FILE_RANGE_WAIT_AFTER = 4 };

/* eio_fallocate flags */
enum {
	EIO_FALLOC_FL_KEEP_SIZE = 1 /* MUST match the value in linux/falloc.h */
};

/* timestamps and differences - feel free to use double in your code directly */
typedef double eio_tstamp;

/* the eio request structure */
enum {
	EIO_CUSTOM,
	EIO_WD_OPEN,
	EIO_WD_CLOSE,

	EIO_CLOSE,
	EIO_DUP2,
	EIO_READ,
	EIO_WRITE,
	EIO_READAHEAD,
	EIO_SENDFILE,
	EIO_FSTAT,
	EIO_FSTATVFS,
	EIO_FTRUNCATE,
	EIO_FUTIME,
	EIO_FCHMOD,
	EIO_FCHOWN,
	EIO_SYNC,
	EIO_FSYNC,
	EIO_FDATASYNC,
	EIO_SYNCFS,
	EIO_MSYNC,
	EIO_MTOUCH,
	EIO_SYNC_FILE_RANGE,
	EIO_FALLOCATE,
	EIO_MLOCK,
	EIO_MLOCKALL,
	EIO_GROUP,
	EIO_NOP,
	EIO_BUSY,

	/* these use wd + ptr1, but are emulated */
	EIO_REALPATH,
	EIO_STATVFS,
	EIO_READDIR,

	/* all the following requests use wd + ptr1 as path in xxxat functions */
	EIO_OPEN,
	EIO_STAT,
	EIO_LSTAT,
	EIO_TRUNCATE,
	EIO_UTIME,
	EIO_CHMOD,
	EIO_CHOWN,
	EIO_UNLINK,
	EIO_RMDIR,
	EIO_MKDIR,
	EIO_RENAME,
	EIO_MKNOD,
	EIO_LINK,
	EIO_SYMLINK,
	EIO_READLINK,

	EIO_REQ_TYPE_NUM
};

/* mlockall constants */
enum {
	EIO_MCL_CURRENT = 1,
	EIO_MCL_FUTURE = 2,
};

/* request priorities */

enum {
	EIO_PRI_MIN = -4,
	EIO_PRI_MAX = 4,
	EIO_PRI_DEFAULT = 0,
};

/* eio request structure */
/* this structure is mostly read-only */
/* when initialising it, all members must be zero-initialised */
struct eio_req {
	eio_req volatile* next; /* private ETP */

	eio_wd wd; /* all applicable requests: working directory of pathname, old name; wd_open: return wd */

	eio_ssize_t result; /* result of syscall, e.g. result = read (... */
	off_t offs; /* read, write, truncate, readahead, sync_file_range, fallocate: file offset, mknod: dev_t */
	size_t size; /* read, write, readahead, sendfile, msync, mlock, sync_file_range, fallocate: length */
	void* ptr1; /* all applicable requests: pathname, old name; readdir: optional eio_dirents */
	void* ptr2; /* all applicable requests: new name or memory buffer; readdir: name strings */
	eio_tstamp nv1; /* utime, futime: atime; busy: sleep time */
	eio_tstamp nv2; /* utime, futime: mtime */

	int type; /* EIO_xxx constant ETP */
	int int1; /* all applicable requests: file descriptor; sendfile: output fd; open, msync, mlockall, readdir: flags */
	long int2; /* chown, fchown: uid; sendfile: input fd; open, chmod, mkdir, mknod: file mode, sync_file_range,
	              fallocate: flags */
	long int3; /* chown, fchown: gid; rename, link: working directory of new name */
	int errorno; /* errno value on syscall return */

#if __i386 || __amd64
	unsigned char cancelled;
#else
	sig_atomic_t cancelled;
#endif

	unsigned char flags; /* private */
	signed char pri; /* the priority */

	void* data;
	eio_cb finish;
	void (*destroy)(eio_req* req); /* called when request no longer needed */
	void (*feed)(eio_req* req); /* only used for group requests */

	EIO_REQ_MEMBERS

	eio_req *grp, *grp_prev, *grp_next, *grp_first; /* private */
};

/* _private_ request flags */
enum {
	EIO_FLAG_PTR1_FREE = 0x01, /* need to free(ptr1) */
	EIO_FLAG_PTR2_FREE = 0x02, /* need to free(ptr2) */
	EIO_FLAG_GROUPADD = 0x04 /* some request was added to the group */
};

/* undocumented/unsupported/private helper */
/*void eio_page_align (void **addr, size_t *length);*/

/* returns < 0 on error, errno set
 * need_poll, if non-zero, will be called when results are available
 * and eio_poll_cb needs to be invoked (it MUST NOT call eio_poll_cb itself).
 * done_poll is called when the need to poll is gone.
 */
int eio_init(void (*want_poll)(void), void (*done_poll)(void));

/* must be called regularly to handle pending requests */
/* returns 0 if all requests were handled, -1 if not, or the value of EIO_FINISH if != 0 */
int eio_poll(void);

/* stop polling if poll took longer than duration seconds */
void eio_set_max_poll_time(eio_tstamp nseconds);
/* do not handle more then count requests in one call to eio_poll_cb */
void eio_set_max_poll_reqs(unsigned int nreqs);

/* set minimum required number
 * maximum wanted number
 * or maximum idle number of threads */
void eio_set_min_parallel(unsigned int nthreads);
void eio_set_max_parallel(unsigned int nthreads);
void eio_set_max_idle(unsigned int nthreads);
void eio_set_idle_timeout(unsigned int seconds);

unsigned int eio_nreqs(void); /* number of requests in-flight */
unsigned int eio_nready(void); /* number of not-yet handled requests */
unsigned int eio_npending(void); /* number of finished but unhandled requests */
unsigned int eio_nthreads(void); /* number of worker threads in use currently */

/*****************************************************************************/
/* convenience wrappers */

#ifndef EIO_NO_WRAPPERS
eio_req* eio_wd_open(const char* path, int pri, eio_cb cb, void* data); /* result=wd */
eio_req* eio_wd_close(eio_wd wd, int pri, eio_cb cb, void* data);
eio_req* eio_nop(int pri, eio_cb cb, void* data); /* does nothing except go through the whole process */
eio_req* eio_busy(eio_tstamp delay,
                  int pri,
                  eio_cb cb,
                  void* data); /* ties a thread for this long, simulating busyness */
eio_req* eio_sync(int pri, eio_cb cb, void* data);
eio_req* eio_fsync(int fd, int pri, eio_cb cb, void* data);
eio_req* eio_fdatasync(int fd, int pri, eio_cb cb, void* data);
eio_req* eio_syncfs(int fd, int pri, eio_cb cb, void* data);
eio_req* eio_msync(void* addr, size_t length, int flags, int pri, eio_cb cb, void* data);
eio_req* eio_mtouch(void* addr, size_t length, int flags, int pri, eio_cb cb, void* data);
eio_req* eio_mlock(void* addr, size_t length, int pri, eio_cb cb, void* data);
eio_req* eio_mlockall(int flags, int pri, eio_cb cb, void* data);
eio_req* eio_sync_file_range(int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void* data);
eio_req* eio_fallocate(int fd, int mode, off_t offset, size_t len, int pri, eio_cb cb, void* data);
eio_req* eio_close(int fd, int pri, eio_cb cb, void* data);
eio_req* eio_readahead(int fd, off_t offset, size_t length, int pri, eio_cb cb, void* data);
eio_req* eio_read(int fd, void* buf, size_t length, off_t offset, int pri, eio_cb cb, void* data);
eio_req* eio_write(int fd, void* buf, size_t length, off_t offset, int pri, eio_cb cb, void* data);
eio_req* eio_fstat(int fd, int pri, eio_cb cb, void* data); /* stat buffer=ptr2 allocated dynamically */
eio_req* eio_fstatvfs(int fd, int pri, eio_cb cb, void* data); /* stat buffer=ptr2 allocated dynamically */
eio_req* eio_futime(int fd, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void* data);
eio_req* eio_ftruncate(int fd, off_t offset, int pri, eio_cb cb, void* data);
eio_req* eio_fchmod(int fd, mode_t mode, int pri, eio_cb cb, void* data);
eio_req* eio_fchown(int fd, eio_uid_t uid, eio_gid_t gid, int pri, eio_cb cb, void* data);
eio_req* eio_dup2(int fd, int fd2, int pri, eio_cb cb, void* data);
eio_req* eio_sendfile(int out_fd, int in_fd, off_t in_offset, size_t length, int pri, eio_cb cb, void* data);
eio_req* eio_open(const char* path, int flags, mode_t mode, int pri, eio_cb cb, void* data);
eio_req* eio_utime(const char* path, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void* data);
eio_req* eio_truncate(const char* path, off_t offset, int pri, eio_cb cb, void* data);
eio_req* eio_chown(const char* path, eio_uid_t uid, eio_gid_t gid, int pri, eio_cb cb, void* data);
eio_req* eio_chmod(const char* path, mode_t mode, int pri, eio_cb cb, void* data);
eio_req* eio_mkdir(const char* path, mode_t mode, int pri, eio_cb cb, void* data);
eio_req* eio_readdir(const char* path,
                     int flags,
                     int pri,
                     eio_cb cb,
                     void* data); /* result=ptr2 allocated dynamically */
eio_req* eio_rmdir(const char* path, int pri, eio_cb cb, void* data);
eio_req* eio_unlink(const char* path, int pri, eio_cb cb, void* data);
eio_req* eio_readlink(const char* path, int pri, eio_cb cb, void* data); /* result=ptr2 allocated dynamically */
eio_req* eio_realpath(const char* path, int pri, eio_cb cb, void* data); /* result=ptr2 allocated dynamically */
eio_req* eio_stat(const char* path, int pri, eio_cb cb, void* data); /* stat buffer=ptr2 allocated dynamically */
eio_req* eio_lstat(const char* path, int pri, eio_cb cb, void* data); /* stat buffer=ptr2 allocated dynamically */
eio_req* eio_statvfs(const char* path, int pri, eio_cb cb, void* data); /* stat buffer=ptr2 allocated dynamically */
eio_req* eio_mknod(const char* path, mode_t mode, dev_t dev, int pri, eio_cb cb, void* data);
eio_req* eio_link(const char* path, const char* new_path, int pri, eio_cb cb, void* data);
eio_req* eio_symlink(const char* path, const char* new_path, int pri, eio_cb cb, void* data);
eio_req* eio_rename(const char* path, const char* new_path, int pri, eio_cb cb, void* data);
eio_req* eio_custom(void (*execute)(eio_req*), int pri, eio_cb cb, void* data);
#endif

/*****************************************************************************/
/* groups */

eio_req* eio_grp(eio_cb cb, void* data);
void eio_grp_feed(eio_req* grp, void (*feed)(eio_req* req), int limit);
void eio_grp_limit(eio_req* grp, int limit);
void eio_grp_add(eio_req* grp, eio_req* req);
void eio_grp_cancel(eio_req* grp); /* cancels all sub requests but not the group */

/*****************************************************************************/
/* request api */

/* true if the request was cancelled, useful in the invoke callback */
#define EIO_CANCELLED(req) ((req)->cancelled)

#define EIO_RESULT(req) ((req)->result)
/* returns a pointer to the result buffer allocated by eio */
#define EIO_BUF(req) ((req)->ptr2)
#define EIO_STAT_BUF(req) ((EIO_STRUCT_STAT*)EIO_BUF(req))
#define EIO_STATVFS_BUF(req) ((EIO_STRUCT_STATVFS*)EIO_BUF(req))
#define EIO_PATH(req) ((char*)(req)->ptr1)

/* submit a request for execution */
void eio_submit(eio_req* req);
/* cancel a request as soon fast as possible, if possible */
void eio_cancel(eio_req* req);

/*****************************************************************************/
/* convenience functions */

eio_ssize_t eio_sendfile_sync(int ofd, int ifd, off_t offset, size_t count);

#ifdef __cplusplus
}
#endif

#endif