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[/] [or1k/] [trunk/] [gdb-5.0/] [gdb/] [osf-share/] [AT386/] [cma_thread_io.h] - Blame information for rev 106

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1 106 markom
/*
2
 * (c) Copyright 1990-1996 OPEN SOFTWARE FOUNDATION, INC.
3
 * (c) Copyright 1990-1996 HEWLETT-PACKARD COMPANY
4
 * (c) Copyright 1990-1996 DIGITAL EQUIPMENT CORPORATION
5
 * (c) Copyright 1991, 1992 Siemens-Nixdorf Information Systems
6
 * To anyone who acknowledges that this file is provided "AS IS" without
7
 * any express or implied warranty: permission to use, copy, modify, and
8
 * distribute this file for any purpose is hereby granted without fee,
9
 * provided that the above copyright notices and this notice appears in
10
 * all source code copies, and that none of the names listed above be used
11
 * in advertising or publicity pertaining to distribution of the software
12
 * without specific, written prior permission.  None of these organizations
13
 * makes any representations about the suitability of this software for
14
 * any purpose.
15
 */
16
/*
17
 *      Header file for thread synchrounous I/O
18
 */
19
 
20
#ifndef CMA_THREAD_IO
21
#define CMA_THREAD_IO
22
 
23
/*
24
 *  INCLUDE FILES
25
 */
26
 
27
#include <cma_config.h>
28
#include <sys/file.h>
29
#include <cma.h>
30
#include <sys/types.h>
31
#include <sys/time.h>
32
#include <cma_init.h>
33
#include <cma_errors.h>
34
 
35
/*
36
 * CONSTANTS
37
 */
38
 
39
/*
40
 * Define symbols which indicate whether to compile code for obsolete
41
 * "non-blocking mode" flags:  FNDELAY and FNBLOCK.  If the obsolete
42
 * symbols are defined, and if their replacement symbols are defined
43
 * and are different or if they are undefined, then define a symbol
44
 * that says to compile the code in; otherwise no code will be compiled
45
 * for these obsolete symbols.
46
 */
47
#ifdef FNDELAY
48
# ifdef O_NDELAY
49
#  if O_NDELAY != FNDELAY
50
#   define _CMA_FNDELAY_
51
#  endif
52
# else
53
#  define _CMA_FNDELAY_
54
# endif
55
#endif
56
 
57
#ifdef FNBLOCK
58
# ifdef O_NONBLOCK
59
#  if O_NONBLOCK != FNBLOCK
60
#   define _CMA_FNBLOCK_
61
#  endif
62
# else
63
#  define _CMA_FNBLOCK_
64
# endif
65
#endif
66
 
67
 
68
extern cma_t_boolean cma_is_open(int);
69
/*
70
 * Maximum number of files (ie, max_fd+1)
71
 */
72
#define cma__c_mx_file  FD_SETSIZE
73
 
74
/*
75
 * Number of bits per file descriptor bit mask (ie number of bytes * bits/byte)
76
 */
77
#define cma__c_nbpm     NFDBITS
78
 
79
/*
80
 * TYPE DEFINITIONS
81
 */
82
 
83
typedef enum CMA__T_IO_TYPE {
84
    cma__c_io_read   = 0,
85
    cma__c_io_write  = 1,
86
    cma__c_io_except = 2
87
    } cma__t_io_type;
88
#define cma__c_max_io_type      2
89
 
90
/*
91
 * From our local <sys/types.h>:
92
 *
93
 *  typedef long    fd_mask;
94
 *
95
 *  typedef struct fd_set {
96
 *          fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
97
 *  } fd_set;
98
 *
99
 */
100
typedef fd_mask cma__t_mask;
101
typedef fd_set  cma__t_file_mask;
102
 
103
 
104
/*
105
 *  GLOBAL DATA
106
 */
107
 
108
/*
109
 * Maximum number of files (ie, max_fd+1) as determined by getdtablesize().
110
 */
111
extern int      cma__g_mx_file;
112
 
113
/*
114
 * Number of submasks (ie "int" sized chunks) per file descriptor mask as
115
 * determined by getdtablesize().
116
 */
117
extern int      cma__g_nspm;
118
 
119
/*
120
 * MACROS
121
 */
122
 
123
/*
124
 * Define a constant for the errno value which indicates that the requested
125
 * operation was not performed because it would block the process.
126
 */
127
# define cma__is_blocking(s) \
128
    ((s == EAGAIN) || (s == EWOULDBLOCK) || (s == EINPROGRESS) || \
129
     (s == EALREADY) || (s == EDEADLK))
130
 
131
/*
132
*       It is necessary to issue an I/O function, before calling cma__io_wait()
133
*       in the following cases:
134
*
135
*               *       This file descriptor has been set non-blocking by CMA
136
*               *       This file descriptor has been set non-blocking by the user.
137
*/
138
 
139
#define cma__issue_io_call(fd)                                  \
140
        ( (cma__g_file[fd]->non_blocking) || \
141
          (cma__g_file[fd]->user_fl.user_non_blocking) )
142
 
143
 
144
#define cma__set_user_nonblocking(flags) \
145
 
146
/*
147
 * Determine if the file is open
148
 */
149
/*
150
 * If the file gets closed while waiting for the mutex cma__g_file[rfd]
151
 * gets set to null. This results in a crash if NDEBUG is set to 0
152
 * since cma__int_lock tries to dereference it to set the mutex ownership
153
 * after it gets the mutex. The following will still set the ownership
154
 * in cma__int_lock so we'll set it back to noone if cma__g_file is null
155
 * when we come back just in case it matters. It shouldn't since its no
156
 * longer in use but.....
157
 * Callers of this should recheck cma__g_file after the reservation to
158
 * make sure continueing makes sense.
159
 */
160
#define cma__fd_reserve(rfd)    \
161
                { \
162
                cma__t_int_mutex *__mutex__; \
163
                __mutex__ = cma__g_file[rfd]->mutex; \
164
                cma__int_lock (__mutex__); \
165
                if(cma__g_file[rfd] == (cma__t_file_obj *)cma_c_null_ptr) \
166
                        cma__int_unlock(__mutex__); \
167
                }
168
 
169
 
170
/*
171
 * Unreserve a file descriptor
172
 */
173
#define cma__fd_unreserve(ufd)  cma__int_unlock (cma__g_file[ufd]->mutex)
174
 
175
/*
176
 * AND together two select file descriptor masks
177
 */
178
#define cma__fdm_and(target,a,b)                                        \
179
        {                                                               \
180
        int __i__ = cma__g_nspm;                                        \
181
        while (__i__--)                                                 \
182
            (target)->fds_bits[__i__] =                                 \
183
                (a)->fds_bits[__i__] & (b)->fds_bits[__i__];            \
184
        }
185
 
186
/*
187
 * Clear a bit in a select file descriptor mask
188
 *
189
 * FD_CLR(n, p)  :=  ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
190
 */
191
#define cma__fdm_clr_bit(n,p)   FD_CLR (n, p)
192
 
193
/*
194
 * Copy the contents of one file descriptor mask into another.  If the
195
 * destination operand is null, do nothing; if the source operand is null,
196
 * simply zero the destination.
197
 */
198
#define cma__fdm_copy(src,dst,nfds) {                                   \
199
        if (dst)                                                        \
200
            if (src) {                                                  \
201
                cma__t_mask *__s__ = (cma__t_mask *)(src);              \
202
                cma__t_mask *__d__ = (cma__t_mask *)(dst);              \
203
                int __i__;                                              \
204
                for (__i__ = 0; __i__ < (nfds); __i__ += cma__c_nbpm)    \
205
                    *__d__++ = *__s__++;                                \
206
                }                                                       \
207
            else                                                        \
208
                cma__fdm_zero (dst);                                    \
209
            }
210
 
211
/*
212
 * To increment count for each bit set in fd - mask
213
 */
214
#define cma__fdm_count_bits(map,count)                                  \
215
        {                                                               \
216
        int     __i__ = cma__g_nspm;                                    \
217
        while (__i__--) {                                               \
218
            cma__t_mask    __tm__;                                      \
219
            __tm__ = (map)->fds_bits[__i__];                            \
220
            while(__tm__) {                                             \
221
                (count)++;                                              \
222
                __tm__ &= ~(__tm__ & (-__tm__)); /* Assumes 2's comp */ \
223
                }                                                       \
224
            }                                                           \
225
        }
226
 
227
/*
228
 * Test if a bit is set in a select file descriptor mask
229
 *
230
 * FD_ISSET(n,p)  :=  ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
231
 */
232
#define cma__fdm_is_set(n,p)    FD_ISSET (n, p)
233
 
234
/*
235
 * OR together two select file descriptor masks
236
 */
237
#define cma__fdm_or(target,a,b)                                         \
238
        {                                                               \
239
        int __i__ = cma__g_nspm;                                        \
240
        while (__i__--)                                                 \
241
            (target)->fds_bits[__i__] =                                 \
242
                (a)->fds_bits[__i__] | (b)->fds_bits[__i__];            \
243
        }
244
 
245
/*
246
 * Set a bit in a select file descriptor mask
247
 *
248
 * FD_SET(n,p)  :=  ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
249
 */
250
#define cma__fdm_set_bit(n,p)   FD_SET (n, p)
251
 
252
/*
253
 * Clear a select file descriptor mask.
254
 */
255
#define cma__fdm_zero(n)                                                \
256
        cma__memset ((char *) n, 0, cma__g_nspm * sizeof(cma__t_mask))
257
 
258
 
259
 
260
/*
261
 * CMA "thread-synchronous" I/O read/write operations
262
 */
263
 
264
    /*
265
     * Since all CMA "thread-synchronous" I/O (read or write) operations on
266
     * U*ix follow the exact same structure, the wrapper routines have been
267
     * condensed into a macro.
268
     *
269
     * The steps performed are as follows:
270
     *  1. Check that the file descriptor is a legitimate value.
271
     *  2. Check that the entry in the CMA file "database" which corresponds to
272
     *      the file descriptor indicates that the "file" was "opened" by CMA.
273
     *  3. Reserve the file, to serialized access to files.  This not only
274
     *      simplifies things, but also defends against non-reentrancy.
275
     *  4. If the "file" is "set" for non-blocking I/O, check if we
276
     *      have actually set the file non-blocking yet, and if not do so.
277
     *      Then, issue the I/O operantion.
278
     *      Success or failure is returned immediately, after unreserving the
279
     *      file.  If the error indicates that the operation would have caused
280
     *      the process to block, continue to the next step.
281
     *  5. The I/O prolog adds this "file" to the global bit mask, which
282
     *      represents all "files" which have threads waiting to perform I/O on
283
     *      them, and causes the thread to block on the condition variable for
284
     *      this "file".  Periodically, a select is done on this global bit
285
     *      mask, and the condition variables corresponding to "files" which
286
     *      are ready for I/O are signaled, releasing those waiting threads to
287
     *      perform their I/O.
288
     *  6. When the thread returns from the I/O prolog, it can (hopefully)
289
     *      perform its operation without blocking the process.
290
     *  7. The I/O epilog clears the bit in the global mask and/or signals the
291
     *      the next thread waiting for this "file", as appropriate.
292
     *  8. If the I/O failed, continue to loop.
293
     *  9. Finally, the "file" is unreserved, as we're done with it, and the
294
     *      result of the operation is returned.
295
     *
296
     *
297
     * Note:  currently, we believe that timeslicing which is based on the
298
     *      virtual-time timer does not cause system calls to return EINTR.
299
     *      Threfore, any EINTR returns are relayed directly to the caller.
300
     *      On platforms which do not support a virtual-time timer, the code
301
     *      should probably catch EINTR returns and restart the system call.
302
     */
303
 
304
/*
305
 * This macro is used for both read-type and write-type functions.
306
 *
307
 * Note:  the second call to "func" may require being bracketed in a
308
 *        cma__interrupt_disable/cma__interrupt_enable pair, but we'll
309
 *        wait and see if this is necessary.
310
 */
311
#define cma__ts_func(func,fd,arglist,type,post_process) { \
312
    cma_t_integer   __res__; \
313
    cma_t_boolean   __done__ = cma_c_false; \
314
    if ((fd < 0) || (fd >= cma__g_mx_file)) return (cma__set_errno (EBADF), -1); \
315
    if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \
316
    cma__fd_reserve (fd); \
317
    if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \
318
    if (cma__issue_io_call(fd)) {\
319
        if ((!cma__g_file[fd]->set_non_blocking) && \
320
                (cma__g_file[fd]->non_blocking == cma_c_true)) \
321
            cma__set_nonblocking(fd); \
322
        cma__interrupt_disable (0); \
323
        TRY { \
324
            __res__ = func arglist; \
325
            } \
326
        CATCH_ALL { \
327
            cma__interrupt_enable (0); \
328
            cma__fd_unreserve (fd); \
329
            RERAISE; \
330
            } \
331
        ENDTRY \
332
        cma__interrupt_enable (0); \
333
        if ((__res__ != -1) \
334
                || (!cma__is_blocking (errno)) \
335
                || (cma__g_file[fd]->user_fl.user_non_blocking)) \
336
            __done__ = cma_c_true; \
337
        } \
338
    if (__done__) { \
339
        cma__fd_unreserve (fd); \
340
        } \
341
    else { \
342
        TRY { \
343
            cma__io_prolog (type, fd); \
344
            while (!__done__) { \
345
                cma__io_wait (type, fd); \
346
                __res__ = func arglist; \
347
                if ((__res__ != -1) \
348
                        || (!cma__is_blocking (errno)) \
349
                        || (cma__g_file[fd]->user_fl.user_non_blocking)) \
350
                    __done__ = cma_c_true; \
351
                } \
352
            } \
353
        FINALLY { \
354
            cma__io_epilog (type, fd); \
355
            cma__fd_unreserve (fd); \
356
            } \
357
        ENDTRY \
358
        } \
359
    if (__res__ != -1)  post_process; \
360
    return __res__;  \
361
    }
362
 
363
    /*
364
     * Since most CMA "thread-synchronous" I/O ("open"-type) operations on
365
     * U*ix follow the exact same structure, the wrapper routines have been
366
     * condensed into a macro.
367
     *
368
     * The steps performed are as follows:
369
     *  1. Issue the open function.
370
     *  2. If the value returned indicates an error, return it to the caller.
371
     *  3. If the file descriptor returned is larger than what we think is the
372
     *      maximum value (ie if it is too big for our database) then bugcheck.
373
     *  4. "Open" the "file" in the CMA file database.
374
     *  5. Return the file descriptor value to the caller.
375
     *
376
     * FIX-ME: for the time being, if the I/O operation returns EINTR, we
377
     *      simply return it to the caller; eventually, we should catch this
378
     *      and "do the right thing" (if we can figure out what that is).
379
     */
380
 
381
/*
382
 * This macro is used for all "open"-type functions which return a single file
383
 * desciptor by immediate value.
384
 */
385
#define cma__ts_open(func,arglist,post_process)  {              \
386
    int __fd__;                                                 \
387
    TRY {                                                       \
388
        cma__int_init ();                                       \
389
        cma__int_lock (cma__g_io_data_mutex);                   \
390
        __fd__ = func arglist;                                  \
391
        cma__int_unlock (cma__g_io_data_mutex);                 \
392
        if (__fd__ >= 0 && __fd__ < cma__g_mx_file)              \
393
            post_process;                                       \
394
        }                                                       \
395
    CATCH_ALL                                                   \
396
        {                                                       \
397
        cma__set_errno (EBADF);                                 \
398
        __fd__ = -1;                                            \
399
        }                                                       \
400
    ENDTRY                                                      \
401
    if (__fd__ >= cma__g_mx_file)                               \
402
        cma__bugcheck ("cma__ts_open:  fd is too large");       \
403
    return __fd__;                                              \
404
    }
405
/*
406
 * This macro is used for all "open"-type functions which return a pair of file
407
 * desciptors by reference parameter.
408
 */
409
#define cma__ts_open2(func,fdpair,arglist,post_process)  {              \
410
    int     __res__;                                                    \
411
    TRY {                                                               \
412
        cma__int_init ();                                               \
413
        cma__int_lock (cma__g_io_data_mutex);                           \
414
        __res__ = func arglist;                                         \
415
        cma__int_unlock (cma__g_io_data_mutex);                         \
416
        if (__res__ >= 0 && fdpair[0] < cma__g_mx_file                    \
417
                && fdpair[1] < cma__g_mx_file)                          \
418
            post_process;                                               \
419
        }                                                               \
420
    CATCH_ALL                                                           \
421
        {                                                               \
422
        cma__set_errno (EBADF);                                         \
423
        __res__ = -1;                                                   \
424
        }                                                               \
425
    ENDTRY                                                              \
426
    if ((fdpair[0] >= cma__g_mx_file) || (fdpair[1] >= cma__g_mx_file)) \
427
        cma__bugcheck ("cma__ts_open2:  one of fd's is too large"); \
428
    return __res__;                                                     \
429
    }
430
 
431
/*
432
 * INTERNAL INTERFACES
433
 */
434
extern void cma__close_general (int);
435
 
436
extern void cma__init_thread_io (void);
437
 
438
extern cma_t_boolean cma__io_available (cma__t_io_type,int,struct timeval *);
439
 
440
extern void cma__io_epilog (cma__t_io_type,int);
441
 
442
extern void cma__io_prolog (cma__t_io_type,int);
443
 
444
extern void cma__io_wait (cma__t_io_type,int);
445
 
446
extern void cma__open_general (int);
447
 
448
extern void cma__reinit_thread_io (int);
449
 
450
extern void cma__set_nonblocking (int);
451
 
452
extern void cma__set_user_nonblock_flags (int,int);
453
 
454
extern cma_t_boolean cma__is_open (int);
455
 
456
 
457
#endif

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