about summary refs log tree commit diff
path: root/sysdeps/mach/hurd/recvmsg.c
blob: dfe5c2b36bbf780876a4df2b7a1af0a13479b845 (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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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; see the file COPYING.LIB.  If
   not, see <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <string.h>
#include <sys/socket.h>

#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/socket.h>
#include <sysdep-cancel.h>

/* Receive a message as described by MESSAGE from socket FD.
   Returns the number of bytes read or -1 for errors.  */
ssize_t
__libc_recvmsg (int fd, struct msghdr *message, int flags)
{
  error_t err;
  addr_port_t aport;
  char *data = NULL;
  mach_msg_type_number_t len = 0;
  mach_port_t *ports, *newports = NULL;
  mach_msg_type_number_t nports = 0;
  struct cmsghdr *cmsg;
  char *cdata = NULL;
  mach_msg_type_number_t clen = 0;
  size_t amount;
  char *buf;
  int nfds, *opened_fds = NULL;
  int i, ii, j;
  int newfds;
  int cancel_oldtype;

  error_t reauthenticate (mach_port_t port, mach_port_t *result)
    {
      error_t err;
      mach_port_t ref;
      ref = __mach_reply_port ();
      int cancel_oldtype;

      cancel_oldtype = LIBC_CANCEL_ASYNC();
      do
	err = __io_reauthenticate (port, ref, MACH_MSG_TYPE_MAKE_SEND);
      while (err == EINTR);
      if (!err)
	do
	  err = __USEPORT_CANCEL (AUTH, __auth_user_authenticate (port,
					  ref, MACH_MSG_TYPE_MAKE_SEND,
					  result));
	while (err == EINTR);
      LIBC_CANCEL_RESET (cancel_oldtype);

      __mach_port_destroy (__mach_task_self (), ref);
      return err;
    }

  /* Find the total number of bytes to be read.  */
  amount = 0;
  for (i = 0; i < message->msg_iovlen; i++)
    {
      amount += message->msg_iov[i].iov_len;

      /* As an optimization, we set the initial values of DATA and LEN
         from the first non-empty iovec.  This kicks-in in the case
         where the whole packet fits into that iovec buffer.  */
      if (data == NULL && message->msg_iov[i].iov_len > 0)
	{
	  data = message->msg_iov[i].iov_base;
	  len = message->msg_iov[i].iov_len;
	}
    }

  buf = data;
  cancel_oldtype = LIBC_CANCEL_ASYNC();
  err = HURD_DPORT_USE_CANCEL (fd, __socket_recv (port, &aport,
						  flags, &data, &len,
						  &ports, &nports,
						  &cdata, &clen,
						  &message->msg_flags, amount));
  LIBC_CANCEL_RESET (cancel_oldtype);
  if (err)
    return __hurd_sockfail (fd, flags, err);

  if (message->msg_name != NULL && aport != MACH_PORT_NULL)
    {
      char *buf = message->msg_name;
      mach_msg_type_number_t buflen = message->msg_namelen;
      int type;

      cancel_oldtype = LIBC_CANCEL_ASYNC();
      err = __socket_whatis_address (aport, &type, &buf, &buflen);
      LIBC_CANCEL_RESET (cancel_oldtype);

      if (err == EOPNOTSUPP)
	/* If the protocol server can't tell us the address, just return a
	   zero-length one.  */
	{
	  buf = message->msg_name;
	  buflen = 0;
	  err = 0;
	}

      if (err)
	{
	  __mach_port_deallocate (__mach_task_self (), aport);
	  return __hurd_sockfail (fd, flags, err);
	}

      if (message->msg_namelen > buflen)
	message->msg_namelen = buflen;

      if (buf != message->msg_name)
	{
	  memcpy (message->msg_name, buf, message->msg_namelen);
	  __vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
	}

      if (buflen > 0)
	((struct sockaddr *) message->msg_name)->sa_family = type;
    }
  else if (message->msg_name != NULL)
    message->msg_namelen = 0;

  __mach_port_deallocate (__mach_task_self (), aport);

  if (buf == data)
    buf += len;
  else
    {
      /* Copy the data into MSG.  */
      if (len > amount)
	message->msg_flags |= MSG_TRUNC;
      else
	amount = len;

      buf = data;
      for (i = 0; i < message->msg_iovlen; i++)
	{
#define min(a, b)	((a) > (b) ? (b) : (a))
	  size_t copy = min (message->msg_iov[i].iov_len, amount);

	  memcpy (message->msg_iov[i].iov_base, buf, copy);

	  buf += copy;
	  amount -= copy;
	  if (len == 0)
	    break;
	}

      __vm_deallocate (__mach_task_self (), (vm_address_t) data, len);
    }

  /* Copy the control message into MSG.  */
  if (clen > message->msg_controllen)
    message->msg_flags |= MSG_CTRUNC;
  else
    message->msg_controllen = clen;
  memcpy (message->msg_control, cdata, message->msg_controllen);

  if (nports > 0)
    {
      newports = __alloca (nports * sizeof (mach_port_t));
      opened_fds = __alloca (nports * sizeof (int));
    }

  /* This counts how many ports we processed completely.  */
  i = 0;
  /* This counts how many new fds we create.  */
  newfds = 0;

  for (cmsg = CMSG_FIRSTHDR (message);
       cmsg;
       cmsg = CMSG_NXTHDR (message, cmsg))
  {
    if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
      {
	/* SCM_RIGHTS support.  */
	/* The fd's flags are passed in the control data.  */
	int *fds = (int *) CMSG_DATA (cmsg);
	nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
	       / sizeof (int);

	for (j = 0; j < nfds; j++)
	  {
	    err = reauthenticate (ports[i], &newports[newfds]);
	    if (err)
	      goto cleanup;
	    fds[j] = opened_fds[newfds] = _hurd_intern_fd (newports[newfds],
							   fds[j], 0);
	    if (fds[j] == -1)
	      {
		err = errno;
		__mach_port_deallocate (__mach_task_self (), newports[newfds]);
		goto cleanup;
	      }
	    i++;
	    newfds++;
	  }
      }
  }

  for (i = 0; i < nports; i++)
    __mach_port_deallocate (mach_task_self (), ports[i]);

  __vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);

  return (buf - data);

cleanup:
  /* Clean up all the file descriptors from port 0 to i-1.  */
  if (nports > 0)
    {
      ii = 0;
      newfds = 0;
      for (cmsg = CMSG_FIRSTHDR (message);
	   cmsg;
	   cmsg = CMSG_NXTHDR (message, cmsg))
	{
	  if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
	    {
	      nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
		     / sizeof (int);
	      for (j = 0; j < nfds && ii < i; j++, ii++, newfds++)
	      {
		_hurd_fd_close (_hurd_fd_get (opened_fds[newfds]));
		__mach_port_deallocate (__mach_task_self (), newports[newfds]);
		__mach_port_deallocate (__mach_task_self (), ports[ii]);
	      }
	    }
	}
    }

  __vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);
  return __hurd_fail (err);
}

weak_alias (__libc_recvmsg, recvmsg)
weak_alias (__libc_recvmsg, __recvmsg)