1/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, see <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <string.h>
20#include <sys/socket.h>
21#include <sys/un.h>
22
23#include <hurd.h>
24#include <hurd/fd.h>
25#include <hurd/ifsock.h>
26#include <hurd/socket.h>
27#include <sysdep-cancel.h>
28#include "hurd/hurdsocket.h"
29
30/* Send a message described MESSAGE on socket FD.
31 Returns the number of bytes sent, or -1 for errors. */
32ssize_t
33__libc_sendmsg (int fd, const struct msghdr *message, int flags)
34{
35 error_t err = 0;
36 struct cmsghdr *cmsg;
37 mach_port_t *ports = NULL;
38 mach_msg_type_number_t nports = 0;
39 int *fds, nfds;
40 struct sockaddr_un *addr = message->msg_name;
41 socklen_t addr_len = message->msg_namelen;
42 addr_port_t aport = MACH_PORT_NULL;
43 union
44 {
45 char *ptr;
46 vm_address_t addr;
47 } data = { .ptr = NULL };
48 char data_buf[2048];
49 mach_msg_type_number_t len;
50 mach_msg_type_number_t amount;
51 int dealloc = 0;
52 int socketrpc = 0;
53 int i;
54
55 /* Find the total number of bytes to be written. */
56 len = 0;
57 for (i = 0; i < message->msg_iovlen; i++)
58 {
59 if (message->msg_iov[i].iov_len > 0)
60 {
61 /* As an optimization, if we only have a single non-empty
62 iovec, we set DATA and LEN from it. */
63 if (len == 0)
64 data.ptr = message->msg_iov[i].iov_base;
65 else
66 data.ptr = NULL;
67
68 len += message->msg_iov[i].iov_len;
69 }
70 }
71
72 if (data.ptr == NULL)
73 {
74 size_t to_copy;
75 char *buf;
76
77 /* Allocate a temporary buffer to hold the data. For small
78 amounts of data, we allocate a buffer on the stack. Larger
79 amounts of data are stored in a page-aligned buffer. The
80 limit of 2048 bytes is inspired by the MiG stubs. */
81 if (len > 2048)
82 {
83 err = __vm_allocate (__mach_task_self (), &data.addr, len, 1);
84 if (err)
85 {
86 __set_errno (err);
87 return -1;
88 }
89 dealloc = 1;
90 }
91 else
92 data.ptr = data_buf;
93
94 /* Copy the data into DATA. */
95 to_copy = len;
96 buf = data.ptr;
97 for (i = 0; i < len; i++)
98 {
99#define min(a, b) ((a) > (b) ? (b) : (a))
100 size_t copy = min (message->msg_iov[i].iov_len, to_copy);
101
102 buf = __mempcpy (buf, message->msg_iov[i].iov_base, copy);
103
104 to_copy -= copy;
105 if (to_copy == 0)
106 break;
107 }
108 }
109
110 /* Allocate enough room for ports. */
111 cmsg = CMSG_FIRSTHDR (message);
112 for (; cmsg; cmsg = CMSG_NXTHDR ((struct msghdr *) message, cmsg))
113 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
114 nports += (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
115 / sizeof (int);
116
117 if (nports)
118 ports = __alloca (nports * sizeof (mach_port_t));
119
120 nports = 0;
121 for (cmsg = CMSG_FIRSTHDR (message);
122 cmsg;
123 cmsg = CMSG_NXTHDR ((struct msghdr *) message, cmsg))
124 {
125 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
126 {
127 /* SCM_RIGHTS support: send FDs. */
128 fds = (int *) CMSG_DATA (cmsg);
129 nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
130 / sizeof (int);
131
132 for (i = 0; i < nfds; i++)
133 {
134 err = HURD_DPORT_USE
135 (fds[i],
136 ({
137 err = __io_restrict_auth (port, &ports[nports],
138 0, 0, 0, 0);
139 if (! err)
140 nports++;
141 /* We pass the flags in the control data. */
142 fds[i] = descriptor->flags;
143 err;
144 }));
145
146 if (err)
147 goto out;
148 }
149 }
150 }
151
152 if (addr)
153 {
154 if (addr->sun_family == AF_LOCAL)
155 {
156 char *name = _hurd_sun_path_dupa (addr, addr_len);
157 /* For the local domain, we must look up the name as a file
158 and talk to it with the ifsock protocol. */
159 file_t file = __file_name_lookup (name, 0, 0);
160 if (file == MACH_PORT_NULL)
161 {
162 err = errno;
163 goto out;
164 }
165 err = __ifsock_getsockaddr (file, &aport);
166 __mach_port_deallocate (__mach_task_self (), file);
167 if (err == MIG_BAD_ID || err == EOPNOTSUPP)
168 /* The file did not grok the ifsock protocol. */
169 err = ENOTSOCK;
170 if (err)
171 goto out;
172 }
173 else
174 err = EIEIO;
175 }
176
177 err = HURD_DPORT_USE_CANCEL (fd,
178 ({
179 if (err)
180 err = __socket_create_address (port,
181 addr->sun_family,
182 (char *) addr,
183 addr_len,
184 &aport);
185 if (! err)
186 {
187 /* Send the data. */
188 int cancel_oldtype = LIBC_CANCEL_ASYNC();
189 err = __socket_send (port, aport,
190 flags, data.ptr, len,
191 ports,
192 MACH_MSG_TYPE_COPY_SEND,
193 nports,
194 message->msg_control,
195 message->msg_controllen,
196 &amount);
197 LIBC_CANCEL_RESET (cancel_oldtype);
198 __mach_port_deallocate (__mach_task_self (),
199 aport);
200 }
201 err;
202 }));
203 socketrpc = 1;
204
205 out:
206 for (i = 0; i < nports; i++)
207 __mach_port_deallocate (__mach_task_self (), ports[i]);
208
209 if (dealloc)
210 __vm_deallocate (__mach_task_self (), data.addr, len);
211
212 if (socketrpc)
213 return err ? __hurd_sockfail (fd, flags, err) : amount;
214 else
215 return __hurd_fail (err);
216}
217
218weak_alias (__libc_sendmsg, sendmsg)
219weak_alias (__libc_sendmsg, __sendmsg)
220

source code of glibc/sysdeps/mach/hurd/sendmsg.c