summary refs log tree commit diff
path: root/sysdeps/pthread/aio_cancel.c
blob: 0564c24065a06e8e4f7c06a313e782d0dc683935 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/* Cancel requests associated with given file descriptor.
   Copyright (C) 1997-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */


/* We use an UGLY hack to prevent gcc from finding us cheating.  The
   implementation of aio_cancel and aio_cancel64 are identical and so
   we want to avoid code duplication by using aliases.  But gcc sees
   the different parameter lists and prints a warning.  We define here
   a function so that aio_cancel64 has no prototype.  */
#ifndef aio_cancel
#define aio_cancel64 XXX
#include <aio.h>
/* And undo the hack.  */
#undef aio_cancel64
#endif

#include <assert.h>
#include <errno.h>
#include <fcntl.h>

#include <aio_misc.h>


int
aio_cancel (int fildes, struct aiocb *aiocbp)
{
  struct requestlist *req = NULL;
  int result = AIO_ALLDONE;

  /* If fildes is invalid, error. */
  if (fcntl (fildes, F_GETFL) < 0)
    {
      __set_errno (EBADF);
      return -1;
    }

  /* Request the mutex.  */
  pthread_mutex_lock (&__aio_requests_mutex);

  /* We are asked to cancel a specific AIO request.  */
  if (aiocbp != NULL)
    {
      /* If the AIO request is not for this descriptor it has no value
	 to look for the request block.  */
      if (aiocbp->aio_fildes != fildes)
	{
	  pthread_mutex_unlock (&__aio_requests_mutex);
	  __set_errno (EINVAL);
	  return -1;
	}
      else if (aiocbp->__error_code == EINPROGRESS)
	{
	  struct requestlist *last = NULL;

	  req = __aio_find_req_fd (fildes);

	  if (req == NULL)
	    {
	    not_found:
	      pthread_mutex_unlock (&__aio_requests_mutex);
	      __set_errno (EINVAL);
	      return -1;
	    }

	  while (req->aiocbp != (aiocb_union *) aiocbp)
	    {
	      last = req;
	      req = req->next_prio;
	      if (req == NULL)
		goto not_found;
	    }

	  /* Don't remove the entry if a thread is already working on it.  */
	  if (req->running == allocated)
	    {
	      result = AIO_NOTCANCELED;
	      req = NULL;
	    }
	  else
	    {
	      /* We can remove the entry.  */
	      __aio_remove_request (last, req, 0);

	      result = AIO_CANCELED;

	      req->next_prio = NULL;
	    }
	}
    }
  else
    {
      /* Find the beginning of the list of all requests for this
	 desriptor.  */
      req = __aio_find_req_fd (fildes);

      /* If any request is worked on by a thread it must be the first.
	 So either we can delete all requests or all but the first.  */
      if (req != NULL)
	{
	  if (req->running == allocated)
	    {
	      struct requestlist *old = req;
	      req = req->next_prio;
	      old->next_prio = NULL;

	      result = AIO_NOTCANCELED;

	      if (req != NULL)
		__aio_remove_request (old, req, 1);
	    }
	  else
	    {
	      result = AIO_CANCELED;

	      /* We can remove the entry.  */
	      __aio_remove_request (NULL, req, 1);
	    }
	}
    }

  /* Mark requests as canceled and send signal.  */
  while (req != NULL)
    {
      struct requestlist *old = req;
      assert (req->running == yes || req->running == queued);
      req->aiocbp->aiocb.__error_code = ECANCELED;
      req->aiocbp->aiocb.__return_value = -1;
      __aio_notify (req);
      req = req->next_prio;
      __aio_free_request (old);
    }

  /* Release the mutex.  */
  pthread_mutex_unlock (&__aio_requests_mutex);

  return result;
}

#ifndef aio_cancel
weak_alias (aio_cancel, aio_cancel64)
#endif