File: sendmsg.c

package info (click to toggle)
glibc 2.28-10
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, buster-proposed-updates, experimental, sid
  • size: 272,168 kB
  • sloc: ansic: 1,008,602; asm: 259,607; makefile: 11,271; sh: 10,477; python: 6,910; cpp: 4,992; perl: 2,258; awk: 2,005; yacc: 290; pascal: 182; sed: 73
file content (252 lines) | stat: -rw-r--r-- 6,848 bytes parent folder | download | duplicates (4)
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) 2001-2018 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 <http://www.gnu.org/licenses/>.  */

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

#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/ifsock.h>
#include <hurd/socket.h>
#include <hurd/auth_request.h>
#include "hurd/hurdsocket.h"

/* Send a message described MESSAGE on socket FD.
   Returns the number of bytes sent, or -1 for errors.  */
ssize_t
__libc_sendmsg (int fd, const struct msghdr *message, int flags)
{
  error_t err = 0;
  struct cmsghdr *cmsg;
  mach_port_t *ports = NULL;
  mach_msg_type_number_t nports = 0;
  int *fds, nfds;
  struct sockaddr_un *addr = message->msg_name;
  socklen_t addr_len = message->msg_namelen;
  addr_port_t aport = MACH_PORT_NULL;
  union
  {
    char *ptr;
    vm_address_t addr;
  } data = { .ptr = NULL };
  char data_buf[2048];
  mach_msg_type_number_t len;
  mach_msg_type_number_t amount;
  int dealloc = 0;
  int socketrpc = 0;
  int i;

  /* Find the total number of bytes to be written.  */
  len = 0;
  for (i = 0; i < message->msg_iovlen; i++)
    {
      if (message->msg_iov[i].iov_len > 0)
	{
	  /* As an optimization, if we only have a single non-empty
             iovec, we set DATA and LEN from it.  */
	  if (len == 0)
	    data.ptr = message->msg_iov[i].iov_base;
	  else
	    data.ptr = NULL;

	  len += message->msg_iov[i].iov_len;
	}
    }

  if (data.ptr == NULL)
    {
      size_t to_copy;
      char *buf;

      /* Allocate a temporary buffer to hold the data.  For small
         amounts of data, we allocate a buffer on the stack.  Larger
         amounts of data are stored in a page-aligned buffer.  The
         limit of 2048 bytes is inspired by the MiG stubs.  */
      if (len > 2048)
	{
	  err = __vm_allocate (__mach_task_self (), &data.addr, len, 1);
	  if (err)
	    {
	      __set_errno (err);
	      return -1;
	    }
	  dealloc = 1;
	}
      else
	data.ptr = data_buf;

      /* Copy the data into DATA.  */
      to_copy = len;
      buf = data.ptr;
      for (i = 0; i < len; i++)
	{
#define	min(a, b)	((a) > (b) ? (b) : (a))
	  size_t copy = min (message->msg_iov[i].iov_len, to_copy);

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

	  to_copy -= copy;
	  if (to_copy == 0)
	    break;
	}
    }

  /* Allocate enough room for ports.  */
  cmsg = CMSG_FIRSTHDR (message);
  for (; cmsg; cmsg = CMSG_NXTHDR (message, cmsg))
    if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
      nports += (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
		/ sizeof (int);
    else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS)
      nports++;

  if (nports)
    ports = __alloca (nports * sizeof (mach_port_t));

  nports = 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: send FDs.   */
	  fds = (int *) CMSG_DATA (cmsg);
	  nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
		 / sizeof (int);

	  for (i = 0; i < nfds; i++)
	    {
	      err = HURD_DPORT_USE
		(fds[i],
		 ({
		   err = __io_restrict_auth (port, &ports[nports],
					     0, 0, 0, 0);
		   if (! err)
		     nports++;
		   /* We pass the flags in the control data.  */
		   fds[i] = descriptor->flags;
		   err;
		 }));

	      if (err)
		goto out;
	    }
	}
      else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS)
	{
	  /* SCM_CREDS support: send credentials.   */
	  mach_port_t rendezvous  = __mach_reply_port (), reply;
	  struct cmsgcred *ucredp;

	  err = __mach_port_insert_right (mach_task_self (), rendezvous,
					  rendezvous, MACH_MSG_TYPE_MAKE_SEND);
	  ports[nports++] = rendezvous;
	  if (err)
	    goto out;

	  ucredp = (struct cmsgcred *) CMSG_DATA(cmsg);
	  /* Fill in credentials data */
	  ucredp->cmcred_pid = __getpid();
	  ucredp->cmcred_uid = __getuid();
	  ucredp->cmcred_euid = __geteuid();
	  ucredp->cmcred_gid = __getgid();
	  ucredp->cmcred_ngroups =
	    __getgroups (sizeof (ucredp->cmcred_groups) / sizeof (gid_t),
			 ucredp->cmcred_groups);

	  /* And make auth server authenticate us.  */
	  reply = __mach_reply_port();
	  err = __USEPORT
	    (AUTH, __auth_user_authenticate_request (port,
					reply, MACH_MSG_TYPE_MAKE_SEND_ONCE,
					rendezvous, MACH_MSG_TYPE_MAKE_SEND));
	  __mach_port_deallocate (__mach_task_self (), reply);
	  if (err)
	    goto out;
	}
    }

  if (addr)
    {
      if (addr->sun_family == AF_LOCAL)
	{
	  char *name = _hurd_sun_path_dupa (addr, addr_len);
	  /* For the local domain, we must look up the name as a file
	     and talk to it with the ifsock protocol.  */
	  file_t file = __file_name_lookup (name, 0, 0);
	  if (file == MACH_PORT_NULL)
	    {
	      err = errno;
	      goto out;
	    }
	  err = __ifsock_getsockaddr (file, &aport);
	  __mach_port_deallocate (__mach_task_self (), file);
	  if (err == MIG_BAD_ID || err == EOPNOTSUPP)
	    /* The file did not grok the ifsock protocol.  */
	    err = ENOTSOCK;
	  if (err)
	    goto out;
	}
      else
	err = EIEIO;
    }

  err = HURD_DPORT_USE (fd,
			({
			  if (err)
			    err = __socket_create_address (port,
							   addr->sun_family,
							   (char *) addr,
							   addr_len,
							   &aport);
			  if (! err)
			    {
			      /* Send the data.  */
			      err = __socket_send (port, aport,
						   flags, data.ptr, len,
						   ports,
						   MACH_MSG_TYPE_COPY_SEND,
						   nports,
						   message->msg_control,
						   message->msg_controllen,
						   &amount);
			      __mach_port_deallocate (__mach_task_self (),
						      aport);
			    }
			  err;
			}));
  socketrpc = 1;

 out:
  for (i = 0; i < nports; i++)
    __mach_port_deallocate (__mach_task_self (), ports[i]);

  if (dealloc)
    __vm_deallocate (__mach_task_self (), data.addr, len);

  if (socketrpc)
    return err ? __hurd_sockfail (fd, flags, err) : amount;
  else
    return __hurd_fail (err);
}

weak_alias (__libc_sendmsg, sendmsg)
weak_alias (__libc_sendmsg, __sendmsg)