1 /* Copyright (C) 2001-2023 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. */
32 ssize_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 vm_size_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 return __hurd_fail (err);
86 dealloc = 1;
87 }
88 else
89 data.ptr = data_buf;
90
91 /* Copy the data into DATA. */
92 to_copy = len;
93 buf = data.ptr;
94 for (i = 0; i < len; i++)
95 {
96 #define min(a, b) ((a) > (b) ? (b) : (a))
97 size_t copy = min (message->msg_iov[i].iov_len, to_copy);
98
99 buf = __mempcpy (buf, message->msg_iov[i].iov_base, copy);
100
101 to_copy -= copy;
102 if (to_copy == 0)
103 break;
104 }
105 }
106
107 /* Allocate enough room for ports. */
108 cmsg = CMSG_FIRSTHDR (message);
109 for (; cmsg; cmsg = CMSG_NXTHDR ((struct msghdr *) message, cmsg))
110 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
111 nports += (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
112 / sizeof (int);
113
114 if (nports)
115 ports = __alloca (nports * sizeof (mach_port_t));
116
117 nports = 0;
118 for (cmsg = CMSG_FIRSTHDR (message);
119 cmsg;
120 cmsg = CMSG_NXTHDR ((struct msghdr *) message, cmsg))
121 {
122 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
123 {
124 /* SCM_RIGHTS support: send FDs. */
125 fds = (int *) CMSG_DATA (cmsg);
126 nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
127 / sizeof (int);
128
129 for (i = 0; i < nfds; i++)
130 {
131 err = HURD_DPORT_USE
132 (fds[i],
133 ({
134 err = __io_restrict_auth (port, &ports[nports],
135 0, 0, 0, 0);
136 if (! err)
137 nports++;
138 /* We do not currently have flags to pass. */
139 fds[i] = 0;
140 err;
141 }));
142
143 if (err)
144 goto out;
145 }
146 }
147 }
148
149 if (addr)
150 {
151 if (addr->sun_family == AF_LOCAL)
152 {
153 char *name = _hurd_sun_path_dupa (addr, addr_len);
154 /* For the local domain, we must look up the name as a file
155 and talk to it with the ifsock protocol. */
156 file_t file = __file_name_lookup (name, 0, 0);
157 if (file == MACH_PORT_NULL)
158 {
159 err = errno;
160 goto out;
161 }
162 err = __ifsock_getsockaddr (file, &aport);
163 __mach_port_deallocate (__mach_task_self (), file);
164 if (err == MIG_BAD_ID || err == EOPNOTSUPP)
165 /* The file did not grok the ifsock protocol. */
166 err = ENOTSOCK;
167 if (err)
168 goto out;
169 }
170 else
171 err = EIEIO;
172 }
173
174 err = HURD_DPORT_USE_CANCEL (fd,
175 ({
176 if (err)
177 err = __socket_create_address (port,
178 addr->sun_family,
179 (char *) addr,
180 addr_len,
181 &aport);
182 if (! err)
183 {
184 /* Send the data. */
185 int cancel_oldtype = LIBC_CANCEL_ASYNC();
186 err = __socket_send (port, aport,
187 flags, data.ptr, len,
188 ports,
189 MACH_MSG_TYPE_COPY_SEND,
190 nports,
191 message->msg_control,
192 message->msg_controllen,
193 &amount);
194 LIBC_CANCEL_RESET (cancel_oldtype);
195 if (MACH_PORT_VALID (aport))
196 __mach_port_deallocate (__mach_task_self (),
197 aport);
198 }
199 err;
200 }));
201 socketrpc = 1;
202
203 out:
204 for (i = 0; i < nports; i++)
205 __mach_port_deallocate (__mach_task_self (), ports[i]);
206
207 if (dealloc)
208 __vm_deallocate (__mach_task_self (), data.addr, len);
209
210 if (socketrpc)
211 return err ? __hurd_sockfail (fd, flags, err) : amount;
212 else
213 return __hurd_fail (err);
214 }
215
216 weak_alias (__libc_sendmsg, sendmsg)
217 weak_alias (__libc_sendmsg, __sendmsg)