1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/unix_domain_socket_posix.h"
6
7 #include <errno.h>
8 #include <unistd.h>
9 #include <sys/uio.h>
10 #include <sys/socket.h>
11
12 #include "base/eintr_wrapper.h"
13 #include "base/logging.h"
14 #include "base/pickle.h"
15
16 namespace base {
17
SendMsg(int fd,const void * buf,size_t length,std::vector<int> & fds)18 bool SendMsg(int fd, const void* buf, size_t length, std::vector<int>& fds) {
19 struct msghdr msg;
20 memset(&msg, 0, sizeof(msg));
21 struct iovec iov = {const_cast<void*>(buf), length};
22 msg.msg_iov = &iov;
23 msg.msg_iovlen = 1;
24
25 char* control_buffer = NULL;
26 if (fds.size()) {
27 const unsigned control_len = CMSG_SPACE(sizeof(int) * fds.size());
28 control_buffer = new char[control_len];
29 if (!control_buffer)
30 return false;
31
32 struct cmsghdr *cmsg;
33
34 msg.msg_control = control_buffer;
35 msg.msg_controllen = control_len;
36 cmsg = CMSG_FIRSTHDR(&msg);
37 cmsg->cmsg_level = SOL_SOCKET;
38 cmsg->cmsg_type = SCM_RIGHTS;
39 cmsg->cmsg_len = CMSG_LEN(sizeof(int) * fds.size());
40 memcpy(CMSG_DATA(cmsg), &fds[0], sizeof(int) * fds.size());
41 msg.msg_controllen = cmsg->cmsg_len;
42 }
43
44 const ssize_t r = HANDLE_EINTR(sendmsg(fd, &msg, 0));
45 const bool ret = static_cast<ssize_t>(length) == r;
46 delete[] control_buffer;
47 return ret;
48 }
49
RecvMsg(int fd,void * buf,size_t length,std::vector<int> * fds)50 ssize_t RecvMsg(int fd, void* buf, size_t length, std::vector<int>* fds) {
51 static const unsigned kMaxDescriptors = 16;
52
53 fds->clear();
54
55 struct msghdr msg;
56 memset(&msg, 0, sizeof(msg));
57 struct iovec iov = {buf, length};
58 msg.msg_iov = &iov;
59 msg.msg_iovlen = 1;
60
61 char control_buffer[CMSG_SPACE(sizeof(int) * kMaxDescriptors)];
62 msg.msg_control = control_buffer;
63 msg.msg_controllen = sizeof(control_buffer);
64
65 const ssize_t r = HANDLE_EINTR(recvmsg(fd, &msg, 0));
66 if (r == -1)
67 return -1;
68
69 int* wire_fds = NULL;
70 unsigned wire_fds_len = 0;
71
72 if (msg.msg_controllen > 0) {
73 struct cmsghdr* cmsg;
74 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
75 if (cmsg->cmsg_level == SOL_SOCKET &&
76 cmsg->cmsg_type == SCM_RIGHTS) {
77 const unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0);
78 DCHECK(payload_len % sizeof(int) == 0);
79 wire_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg));
80 wire_fds_len = payload_len / sizeof(int);
81 break;
82 }
83 }
84 }
85
86 if (msg.msg_flags & MSG_TRUNC || msg.msg_flags & MSG_CTRUNC) {
87 for (unsigned i = 0; i < wire_fds_len; ++i)
88 close(wire_fds[i]);
89 errno = EMSGSIZE;
90 return -1;
91 }
92
93 fds->resize(wire_fds_len);
94 memcpy(&(*fds)[0], wire_fds, sizeof(int) * wire_fds_len);
95
96 return r;
97 }
98
SendRecvMsg(int fd,uint8_t * reply,unsigned max_reply_len,int * result_fd,const Pickle & request)99 ssize_t SendRecvMsg(int fd, uint8_t* reply, unsigned max_reply_len, int* result_fd,
100 const Pickle& request) {
101 int fds[2];
102
103 // This socketpair is only used for the IPC and is cleaned up before
104 // returning.
105 if (socketpair(AF_UNIX, SOCK_DGRAM, 0, fds) == -1)
106 return false;
107
108 std::vector<int> fd_vector;
109 fd_vector.push_back(fds[1]);
110 if (!SendMsg(fd, request.data(), request.size(), fd_vector)) {
111 close(fds[0]);
112 close(fds[1]);
113 return -1;
114 }
115 close(fds[1]);
116
117 fd_vector.clear();
118 const ssize_t reply_len = RecvMsg(fds[0], reply, max_reply_len, &fd_vector);
119 close(fds[0]);
120 if (reply_len == -1)
121 return -1;
122
123 if ((fd_vector.size() > 0 && result_fd == NULL) || fd_vector.size() > 1) {
124 for (std::vector<int>::const_iterator
125 i = fd_vector.begin(); i != fd_vector.end(); ++i) {
126 close(*i);
127 }
128
129 NOTREACHED();
130
131 return -1;
132 }
133
134 if (result_fd) {
135 if (fd_vector.size() == 0) {
136 *result_fd = -1;
137 } else {
138 *result_fd = fd_vector[0];
139 }
140 }
141
142 return reply_len;
143 }
144
145 } // namespace base
146