1 // Copyright (c) 2011 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 #ifndef BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_ 6 #define BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_ 7 8 #include <stddef.h> 9 #include <stdint.h> 10 #include <sys/types.h> 11 #include <vector> 12 13 #include "base/base_export.h" 14 #include "base/files/scoped_file.h" 15 #include "base/process/process_handle.h" 16 #include "build/build_config.h" 17 18 namespace base { 19 20 class Pickle; 21 22 class BASE_EXPORT UnixDomainSocket { 23 public: 24 // Maximum number of file descriptors that can be read by RecvMsg(). 25 static const size_t kMaxFileDescriptors; 26 27 #if !defined(OS_NACL_NONSFI) 28 // Use to enable receiving process IDs in RecvMsgWithPid. Should be called on 29 // the receiving socket (i.e., the socket passed to RecvMsgWithPid). Returns 30 // true if successful. 31 static bool EnableReceiveProcessId(int fd); 32 #endif // !defined(OS_NACL_NONSFI) 33 34 // Use sendmsg to write the given msg and include a vector of file 35 // descriptors. Returns true if successful. 36 static bool SendMsg(int fd, 37 const void* msg, 38 size_t length, 39 const std::vector<int>& fds); 40 41 // Use recvmsg to read a message and an array of file descriptors. Returns 42 // -1 on failure. Note: will read, at most, |kMaxFileDescriptors| descriptors. 43 static ssize_t RecvMsg(int fd, 44 void* msg, 45 size_t length, 46 std::vector<ScopedFD>* fds); 47 48 // Same as RecvMsg above, but also returns the sender's process ID (as seen 49 // from the caller's namespace). However, before using this function to 50 // receive process IDs, EnableReceiveProcessId() should be called on the 51 // receiving socket. 52 static ssize_t RecvMsgWithPid(int fd, 53 void* msg, 54 size_t length, 55 std::vector<ScopedFD>* fds, 56 ProcessId* pid); 57 58 #if !defined(OS_NACL_NONSFI) 59 // Perform a sendmsg/recvmsg pair. 60 // 1. This process creates a UNIX SEQPACKET socketpair. Using 61 // connection-oriented sockets (SEQPACKET or STREAM) is critical here, 62 // because if one of the ends closes the other one must be notified. 63 // 2. This process writes a request to |fd| with an SCM_RIGHTS control 64 // message containing on end of the fresh socket pair. 65 // 3. This process blocks reading from the other end of the fresh 66 // socketpair. 67 // 4. The target process receives the request, processes it and writes the 68 // reply to the end of the socketpair contained in the request. 69 // 5. This process wakes up and continues. 70 // 71 // fd: descriptor to send the request on 72 // reply: buffer for the reply 73 // reply_len: size of |reply| 74 // result_fd: (may be NULL) the file descriptor returned in the reply 75 // (if any) 76 // request: the bytes to send in the request 77 static ssize_t SendRecvMsg(int fd, 78 uint8_t* reply, 79 unsigned reply_len, 80 int* result_fd, 81 const Pickle& request); 82 83 // Similar to SendRecvMsg(), but |recvmsg_flags| allows to control the flags 84 // of the recvmsg(2) call. 85 static ssize_t SendRecvMsgWithFlags(int fd, 86 uint8_t* reply, 87 unsigned reply_len, 88 int recvmsg_flags, 89 int* result_fd, 90 const Pickle& request); 91 #endif // !defined(OS_NACL_NONSFI) 92 private: 93 // Similar to RecvMsg, but allows to specify |flags| for recvmsg(2). 94 static ssize_t RecvMsgWithFlags(int fd, 95 void* msg, 96 size_t length, 97 int flags, 98 std::vector<ScopedFD>* fds, 99 ProcessId* pid); 100 }; 101 102 } // namespace base 103 104 #endif // BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_ 105
