1 // Copyright 2011 The Chromium Authors 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_H_ 6 #define BASE_POSIX_UNIX_DOMAIN_SOCKET_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 // Creates a connected pair of UNIX-domain SOCK_SEQPACKET sockets, and passes 23 // ownership of the newly allocated file descriptors to |one| and |two|. 24 // Returns true on success. 25 bool BASE_EXPORT CreateSocketPair(ScopedFD* one, ScopedFD* two); 26 27 class BASE_EXPORT UnixDomainSocket { 28 public: 29 // Maximum number of file descriptors that can be read by RecvMsg(). 30 static const size_t kMaxFileDescriptors; 31 32 // Use to enable receiving process IDs in RecvMsgWithPid. Should be called on 33 // the receiving socket (i.e., the socket passed to RecvMsgWithPid). Returns 34 // true if successful. 35 static bool EnableReceiveProcessId(int fd); 36 37 // Use sendmsg to write the given msg and include a vector of file 38 // descriptors. Returns true if successful. 39 static bool SendMsg(int fd, 40 const void* msg, 41 size_t length, 42 const std::vector<int>& fds); 43 44 // Use recvmsg to read a message and an array of file descriptors. Returns 45 // -1 on failure. Note: will read, at most, |kMaxFileDescriptors| descriptors. 46 static ssize_t RecvMsg(int fd, 47 void* msg, 48 size_t length, 49 std::vector<ScopedFD>* fds); 50 51 // Same as RecvMsg above, but also returns the sender's process ID (as seen 52 // from the caller's namespace). However, before using this function to 53 // receive process IDs, EnableReceiveProcessId() should be called on the 54 // receiving socket. 55 static ssize_t RecvMsgWithPid(int fd, 56 void* msg, 57 size_t length, 58 std::vector<ScopedFD>* fds, 59 ProcessId* pid); 60 61 // Perform a sendmsg/recvmsg pair. 62 // 1. This process creates a UNIX SEQPACKET socketpair. Using 63 // connection-oriented sockets (SEQPACKET or STREAM) is critical here, 64 // because if one of the ends closes the other one must be notified. 65 // 2. This process writes a request to |fd| with an SCM_RIGHTS control 66 // message containing on end of the fresh socket pair. 67 // 3. This process blocks reading from the other end of the fresh 68 // socketpair. 69 // 4. The target process receives the request, processes it and writes the 70 // reply to the end of the socketpair contained in the request. 71 // 5. This process wakes up and continues. 72 // 73 // fd: descriptor to send the request on 74 // reply: buffer for the reply 75 // reply_len: size of |reply| 76 // result_fd: (may be NULL) the file descriptor returned in the reply 77 // (if any) 78 // request: the bytes to send in the request 79 static ssize_t SendRecvMsg(int fd, 80 uint8_t* reply, 81 unsigned reply_len, 82 int* result_fd, 83 const Pickle& request); 84 85 // Similar to SendRecvMsg(), but |recvmsg_flags| allows to control the flags 86 // of the recvmsg(2) call. 87 static ssize_t SendRecvMsgWithFlags(int fd, 88 uint8_t* reply, 89 unsigned reply_len, 90 int recvmsg_flags, 91 int* result_fd, 92 const Pickle& request); 93 94 private: 95 // Similar to RecvMsg, but allows to specify |flags| for recvmsg(2). 96 static ssize_t RecvMsgWithFlags(int fd, 97 void* msg, 98 size_t length, 99 int flags, 100 std::vector<ScopedFD>* fds, 101 ProcessId* pid); 102 }; 103 104 } // namespace base 105 106 #endif // BASE_POSIX_UNIX_DOMAIN_SOCKET_H_ 107