1 |
1181 |
sfurman |
/*
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* (c) Copyright 1990-1996 OPEN SOFTWARE FOUNDATION, INC.
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* (c) Copyright 1990-1996 HEWLETT-PACKARD COMPANY
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* (c) Copyright 1990-1996 DIGITAL EQUIPMENT CORPORATION
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* (c) Copyright 1991, 1992 Siemens-Nixdorf Information Systems
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* To anyone who acknowledges that this file is provided "AS IS" without
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* any express or implied warranty: permission to use, copy, modify, and
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* distribute this file for any purpose is hereby granted without fee,
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* provided that the above copyright notices and this notice appears in
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* all source code copies, and that none of the names listed above be used
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* in advertising or publicity pertaining to distribution of the software
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* without specific, written prior permission. None of these organizations
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* makes any representations about the suitability of this software for
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* any purpose.
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*/
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/*
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*
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* Header file for thread synchrounous I/O
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*/
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#ifndef CMA_THREAD_IO
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#define CMA_THREAD_IO
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/*
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* INCLUDE FILES
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*/
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#include <cma_config.h>
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#include <sys/file.h>
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#include <cma.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <cma_init.h>
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#include <cma_errors.h>
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/*
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* CONSTANTS
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*/
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/*
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* Maximum number of files (ie, max_fd+1)
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*/
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#define cma__c_mx_file FD_SETSIZE
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/*
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* Number of bits per file descriptor bit mask (ie number of bytes * bits/byte)
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*/
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#define cma__c_nbpm NFDBITS
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/*
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* TYPE DEFINITIONS
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*/
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typedef enum CMA__T_IO_TYPE {
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cma__c_io_read = 0,
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cma__c_io_write = 1,
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cma__c_io_except = 2
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} cma__t_io_type;
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#define cma__c_max_io_type 2
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/*
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* From our local <sys/types.h>:
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*
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* typedef long fd_mask;
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*
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* typedef struct fd_set {
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* fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
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* } fd_set;
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*
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*/
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typedef fd_mask cma__t_mask;
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typedef fd_set cma__t_file_mask;
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/*
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* GLOBAL DATA
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*/
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/*
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* Maximum number of files (ie, max_fd+1) as determined by getdtablesize().
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*/
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extern int cma__g_mx_file;
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/*
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* Number of submasks (ie "int" sized chunks) per file descriptor mask as
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* determined by getdtablesize().
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*/
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extern int cma__g_nspm;
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/*
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* MACROS
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*/
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/*
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* Define a constant for the errno value which indicates that the requested
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* operation was not performed because it would block the process.
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*/
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# define cma__is_blocking(s) \
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((s == EAGAIN) || (s == EWOULDBLOCK) || (s == EINPROGRESS) || \
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(s == EALREADY) || (s == EDEADLK))
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/*
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* It is necessary to issue an I/O function, before calling cma__io_wait()
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* in the following cases:
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*
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* * This file descriptor has been set non-blocking by CMA
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* * This file descriptor has been set non-blocking by the user.
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*/
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#define cma__issue_io_call(fd) \
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( (cma__g_file[fd]->non_blocking) || \
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(cma__g_file[fd]->user_fl.user_non_blocking) )
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#define cma__set_user_nonblocking(flags) \
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/*
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* Determine if the file is open
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*/
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/*
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* If the file gets closed while waiting for the mutex cma__g_file[rfd]
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* gets set to null. This results in a crash if NDEBUG is set to 0
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* since cma__int_lock tries to dereference it to set the mutex ownership
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* after it gets the mutex. The following will still set the ownership
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* in cma__int_lock so we'll set it back to noone if cma__g_file is null
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* when we come back just in case it matters. It shouldn't since its no
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* longer in use but.....
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* Callers of this should recheck cma__g_file after the reservation to
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* make sure continueing makes sense.
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*/
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#define cma__fd_reserve(rfd) \
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{ \
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cma__t_int_mutex *__mutex__; \
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__mutex__ = cma__g_file[rfd]->mutex; \
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cma__int_lock (__mutex__); \
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if(cma__g_file[rfd] == (cma__t_file_obj *)cma_c_null_ptr) \
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cma__int_unlock(__mutex__); \
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}
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/*
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* Unreserve a file descriptor
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*/
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#define cma__fd_unreserve(ufd) cma__int_unlock (cma__g_file[ufd]->mutex)
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/*
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* AND together two select file descriptor masks
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*/
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#define cma__fdm_and(target,a,b) \
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{ \
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int __i__ = cma__g_nspm; \
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while (__i__--) \
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(target)->fds_bits[__i__] = \
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(a)->fds_bits[__i__] & (b)->fds_bits[__i__]; \
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}
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/*
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* Clear a bit in a select file descriptor mask
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*
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* FD_CLR(n, p) := ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
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*/
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#define cma__fdm_clr_bit(n,p) FD_CLR (n, p)
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/*
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* Copy the contents of one file descriptor mask into another. If the
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* destination operand is null, do nothing; if the source operand is null,
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* simply zero the destination.
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*/
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#define cma__fdm_copy(src,dst,nfds) { \
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if (dst) \
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if (src) { \
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cma__t_mask *__s__ = (cma__t_mask *)(src); \
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cma__t_mask *__d__ = (cma__t_mask *)(dst); \
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int __i__; \
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for (__i__ = 0; __i__ < (nfds); __i__ += cma__c_nbpm) \
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*__d__++ = *__s__++; \
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} \
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else \
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cma__fdm_zero (dst); \
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}
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/*
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* To increment count for each bit set in fd - mask
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*/
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#define cma__fdm_count_bits(map,count) \
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{ \
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int __i__ = cma__g_nspm; \
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while (__i__--) { \
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cma__t_mask __tm__; \
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__tm__ = (map)->fds_bits[__i__]; \
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while(__tm__) { \
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(count)++; \
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__tm__ &= ~(__tm__ & (-__tm__)); /* Assumes 2's comp */ \
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} \
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} \
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}
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/*
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* Test if a bit is set in a select file descriptor mask
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*
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* FD_ISSET(n,p) := ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
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*/
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#define cma__fdm_is_set(n,p) FD_ISSET (n, p)
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/*
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* OR together two select file descriptor masks
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*/
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#define cma__fdm_or(target,a,b) \
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{ \
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int __i__ = cma__g_nspm; \
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while (__i__--) \
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(target)->fds_bits[__i__] = \
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(a)->fds_bits[__i__] | (b)->fds_bits[__i__]; \
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}
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/*
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* Set a bit in a select file descriptor mask
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*
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* FD_SET(n,p) := ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
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*/
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#define cma__fdm_set_bit(n,p) FD_SET (n, p)
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/*
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* Clear a select file descriptor mask.
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*/
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#define cma__fdm_zero(n) \
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cma__memset ((char *) n, 0, cma__g_nspm * sizeof(cma__t_mask))
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/*
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* CMA "thread-synchronous" I/O read/write operations
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*/
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/*
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241 |
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* Since all CMA "thread-synchronous" I/O (read or write) operations on
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* U*ix follow the exact same structure, the wrapper routines have been
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* condensed into a macro.
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*
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* The steps performed are as follows:
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* 1. Check that the file descriptor is a legitimate value.
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* 2. Check that the entry in the CMA file "database" which corresponds to
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* the file descriptor indicates that the "file" was "opened" by CMA.
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* 3. Reserve the file, to serialized access to files. This not only
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* simplifies things, but also defends against non-reentrancy.
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* 4. If the "file" is "set" for non-blocking I/O, check if we
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* have actually set the file non-blocking yet, and if not do so.
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* Then, issue the I/O operantion.
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* Success or failure is returned immediately, after unreserving the
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* file. If the error indicates that the operation would have caused
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256 |
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* the process to block, continue to the next step.
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257 |
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* 5. The I/O prolog adds this "file" to the global bit mask, which
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258 |
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* represents all "files" which have threads waiting to perform I/O on
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259 |
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* them, and causes the thread to block on the condition variable for
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260 |
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* this "file". Periodically, a select is done on this global bit
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* mask, and the condition variables corresponding to "files" which
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* are ready for I/O are signaled, releasing those waiting threads to
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* perform their I/O.
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* 6. When the thread returns from the I/O prolog, it can (hopefully)
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* perform its operation without blocking the process.
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* 7. The I/O epilog clears the bit in the global mask and/or signals the
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* the next thread waiting for this "file", as appropriate.
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* 8. If the I/O failed, continue to loop.
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* 9. Finally, the "file" is unreserved, as we're done with it, and the
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* result of the operation is returned.
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*
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*
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273 |
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* Note: currently, we believe that timeslicing which is based on the
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* virtual-time timer does not cause system calls to return EINTR.
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* Threfore, any EINTR returns are relayed directly to the caller.
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* On platforms which do not support a virtual-time timer, the code
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* should probably catch EINTR returns and restart the system call.
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*/
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279 |
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|
280 |
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/*
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281 |
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* This macro is used for both read-type and write-type functions.
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*
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283 |
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* Note: the second call to "func" may require being bracketed in a
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284 |
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* cma__interrupt_disable/cma__interrupt_enable pair, but we'll
|
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* wait and see if this is necessary.
|
286 |
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*/
|
287 |
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#define cma__ts_func(func,fd,arglist,type,post_process) { \
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288 |
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cma_t_integer __res__; \
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cma_t_boolean __done__ = cma_c_false; \
|
290 |
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if ((fd < 0) || (fd >= cma__g_mx_file)) return (cma__set_errno (EBADF), -1); \
|
291 |
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if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \
|
292 |
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cma__fd_reserve (fd); \
|
293 |
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if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \
|
294 |
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if (cma__issue_io_call(fd)) {\
|
295 |
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if ((!cma__g_file[fd]->set_non_blocking) && \
|
296 |
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(cma__g_file[fd]->non_blocking == cma_c_true)) \
|
297 |
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cma__set_nonblocking(fd); \
|
298 |
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cma__interrupt_disable (0); \
|
299 |
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TRY { \
|
300 |
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__res__ = func arglist; \
|
301 |
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} \
|
302 |
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CATCH_ALL { \
|
303 |
|
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cma__interrupt_enable (0); \
|
304 |
|
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cma__fd_unreserve (fd); \
|
305 |
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RERAISE; \
|
306 |
|
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} \
|
307 |
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ENDTRY \
|
308 |
|
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cma__interrupt_enable (0); \
|
309 |
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if ((__res__ != -1) \
|
310 |
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|| (!cma__is_blocking (errno)) \
|
311 |
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|| (cma__g_file[fd]->user_fl.user_non_blocking)) \
|
312 |
|
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__done__ = cma_c_true; \
|
313 |
|
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} \
|
314 |
|
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if (__done__) { \
|
315 |
|
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cma__fd_unreserve (fd); \
|
316 |
|
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} \
|
317 |
|
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else { \
|
318 |
|
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TRY { \
|
319 |
|
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cma__io_prolog (type, fd); \
|
320 |
|
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while (!__done__) { \
|
321 |
|
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cma__io_wait (type, fd); \
|
322 |
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__res__ = func arglist; \
|
323 |
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if ((__res__ != -1) \
|
324 |
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|| (!cma__is_blocking (errno)) \
|
325 |
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|| (cma__g_file[fd]->user_fl.user_non_blocking)) \
|
326 |
|
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__done__ = cma_c_true; \
|
327 |
|
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} \
|
328 |
|
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} \
|
329 |
|
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FINALLY { \
|
330 |
|
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cma__io_epilog (type, fd); \
|
331 |
|
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cma__fd_unreserve (fd); \
|
332 |
|
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} \
|
333 |
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ENDTRY \
|
334 |
|
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} \
|
335 |
|
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if (__res__ != -1) post_process; \
|
336 |
|
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return __res__; \
|
337 |
|
|
}
|
338 |
|
|
|
339 |
|
|
/*
|
340 |
|
|
* Since most CMA "thread-synchronous" I/O ("open"-type) operations on
|
341 |
|
|
* U*ix follow the exact same structure, the wrapper routines have been
|
342 |
|
|
* condensed into a macro.
|
343 |
|
|
*
|
344 |
|
|
* The steps performed are as follows:
|
345 |
|
|
* 1. Issue the open function.
|
346 |
|
|
* 2. If the value returned indicates an error, return it to the caller.
|
347 |
|
|
* 3. If the file descriptor returned is larger than what we think is the
|
348 |
|
|
* maximum value (ie if it is too big for our database) then bugcheck.
|
349 |
|
|
* 4. "Open" the "file" in the CMA file database.
|
350 |
|
|
* 5. Return the file descriptor value to the caller.
|
351 |
|
|
*
|
352 |
|
|
* FIX-ME: for the time being, if the I/O operation returns EINTR, we
|
353 |
|
|
* simply return it to the caller; eventually, we should catch this
|
354 |
|
|
* and "do the right thing" (if we can figure out what that is).
|
355 |
|
|
*/
|
356 |
|
|
|
357 |
|
|
/*
|
358 |
|
|
* This macro is used for all "open"-type functions which return a single file
|
359 |
|
|
* desciptor by immediate value.
|
360 |
|
|
*/
|
361 |
|
|
#define cma__ts_open(func,arglist,post_process) { \
|
362 |
|
|
int __fd__; \
|
363 |
|
|
TRY { \
|
364 |
|
|
cma__int_init (); \
|
365 |
|
|
cma__int_lock (cma__g_io_data_mutex); \
|
366 |
|
|
__fd__ = func arglist; \
|
367 |
|
|
cma__int_unlock (cma__g_io_data_mutex); \
|
368 |
|
|
if (__fd__ >= 0 && __fd__ < cma__g_mx_file) \
|
369 |
|
|
post_process; \
|
370 |
|
|
} \
|
371 |
|
|
CATCH_ALL \
|
372 |
|
|
{ \
|
373 |
|
|
cma__set_errno (EBADF); \
|
374 |
|
|
__fd__ = -1; \
|
375 |
|
|
} \
|
376 |
|
|
ENDTRY \
|
377 |
|
|
if (__fd__ >= cma__g_mx_file) \
|
378 |
|
|
cma__bugcheck ("cma__ts_open: fd is too large"); \
|
379 |
|
|
return __fd__; \
|
380 |
|
|
}
|
381 |
|
|
/*
|
382 |
|
|
* This macro is used for all "open"-type functions which return a pair of file
|
383 |
|
|
* desciptors by reference parameter.
|
384 |
|
|
*/
|
385 |
|
|
#define cma__ts_open2(func,fdpair,arglist,post_process) { \
|
386 |
|
|
int __res__; \
|
387 |
|
|
TRY { \
|
388 |
|
|
cma__int_init (); \
|
389 |
|
|
cma__int_lock (cma__g_io_data_mutex); \
|
390 |
|
|
__res__ = func arglist; \
|
391 |
|
|
cma__int_unlock (cma__g_io_data_mutex); \
|
392 |
|
|
if (__res__ >= 0 && fdpair[0] < cma__g_mx_file \
|
393 |
|
|
&& fdpair[1] < cma__g_mx_file) \
|
394 |
|
|
post_process; \
|
395 |
|
|
} \
|
396 |
|
|
CATCH_ALL \
|
397 |
|
|
{ \
|
398 |
|
|
cma__set_errno (EBADF); \
|
399 |
|
|
__res__ = -1; \
|
400 |
|
|
} \
|
401 |
|
|
ENDTRY \
|
402 |
|
|
if ((fdpair[0] >= cma__g_mx_file) || (fdpair[1] >= cma__g_mx_file)) \
|
403 |
|
|
cma__bugcheck ("cma__ts_open2: one of fd's is too large"); \
|
404 |
|
|
return __res__; \
|
405 |
|
|
}
|
406 |
|
|
|
407 |
|
|
/*
|
408 |
|
|
* INTERNAL INTERFACES
|
409 |
|
|
*/
|
410 |
|
|
extern void cma__close_general (int);
|
411 |
|
|
|
412 |
|
|
extern void cma__init_thread_io (void);
|
413 |
|
|
|
414 |
|
|
extern cma_t_boolean cma__io_available (cma__t_io_type,int,struct timeval *);
|
415 |
|
|
|
416 |
|
|
extern void cma__io_epilog (cma__t_io_type,int);
|
417 |
|
|
|
418 |
|
|
extern void cma__io_prolog (cma__t_io_type,int);
|
419 |
|
|
|
420 |
|
|
extern void cma__io_wait (cma__t_io_type,int);
|
421 |
|
|
|
422 |
|
|
extern void cma__open_general (int);
|
423 |
|
|
|
424 |
|
|
extern void cma__reinit_thread_io (int);
|
425 |
|
|
|
426 |
|
|
extern void cma__set_nonblocking (int);
|
427 |
|
|
|
428 |
|
|
extern void cma__set_user_nonblock_flags (int,int);
|
429 |
|
|
|
430 |
|
|
extern cma_t_boolean cma__is_open (int);
|
431 |
|
|
|
432 |
|
|
#endif
|