base/posix/unix_domain_socket_linux.h

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