Socket subsystem implementation

libraries/nacl-mounts/base/KernelProxy.h

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef PACKAGES_LIBRARIES_NACL_MOUNTS_BASE_KERNELPROXY_H_
 #define PACKAGES_LIBRARIES_NACL_MOUNTS_BASE_KERNELPROXY_H_
 
 #include <errno.h>
 #ifdef __GLIBC__
+#include <netdb.h>
 #include <poll.h>
 #endif
 #include <pthread.h>
 #ifdef __GLIBC__
 #include <sys/epoll.h>
 #endif
 #include <sys/stat.h>
 #include <string>
 #include "../base/Mount.h"
 #include "../base/MountManager.h"
+#include "../base/PthreadHelpers.h"
+#include "../net/BaseSocketSubSystem.h"
 #include "../util/Path.h"
 #include "../util/SimpleAutoLock.h"
 #include "../util/SlotAllocator.h"
 
 // KernelProxy handles all of the system calls.  System calls are either
 // (1) handled entirely by the KernelProxy, (2) processed by the
 // KernelProxy and then passed to a Mount, or (3) proccessed by the
 // KernelProxy using other system calls implemented by the Mount.
 class KernelProxy {
  public:
   virtual ~KernelProxy() {}
 
   // Obtain the singleton instance of the kernel proxy.  If no instance
   // has been instantiated, one will be instantiated and returned.
   static KernelProxy *KPInstance();
+#ifdef __GLIBC__
+  // Set socket subsystem reference (not in constructor because it needs to be
+  // created separately and only if you need sockets in your app)
+  void SetSocketSubSystem(BaseSocketSubSystem* bss);
+#endif
 
   // System calls handled by KernelProxy (not mount-specific)
   int chdir(const std::string& path);
   bool getcwd(std::string *buf, size_t size);
   bool getwd(std::string *buf);
   int dup(int oldfd);
+  int dup2(int oldfd, int newfd);
 
   // System calls that take a path as an argument:
   // The kernel proxy will look for the Node associated to the path.  To
   // find the node, the kernel proxy calls the corresponding mounts GetNode()
   // method.  The corresponding  method will be called.  If the node
   // cannot be found, errno is set and -1 is returned.
   int chmod(const std::string& path, mode_t mode);
   int stat(const std::string& path, struct stat *buf);
   int mkdir(const std::string& path, mode_t mode);
   int rmdir(const std::string& path);
@@ skipping 50 matching lines @@
   int recv(int sockfd, void *buf, size_t len, int flags);
   int recvmsg(int sockfd, struct msghdr *msg, int flags);
   int recvfrom(int sockfd, void *buf, size_t len, int flags,
                struct sockaddr *dest_addr, socklen_t* addrlen);
   int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
              const struct timeval *timeout);
   int pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
               const struct timeval *timeout, void* sigmask);
   int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
   int getsockname(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
+  struct hostent* gethostbyname(const char* name);
   int getsockopt(int sockfd, int level, int optname, void *optval,
                  socklen_t* optlen);
   int setsockopt(int sockfd, int level, int optname, const void *optval,
                  socklen_t optlen);
   int shutdown(int sockfd, int how);
   int epoll_create(int size);
   int epoll_create1(int flags);
   int epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);
   int epoll_wait(int epfd, struct epoll_event *events, int maxevents,
                  int timeout);
   int epoll_pwait(int epfd, struct epoll_event *events, int maxevents,
            int timeout, const sigset_t *sigmask, size_t sigset_size);
   int socketpair(int domain, int type, int protocol, int sv[2]);
   int poll(struct pollfd *fds, nfds_t nfds, int timeout);
   int ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
             const sigset_t *sigmask, size_t sigset_size);
 #endif
   MountManager *mm() { return &mm_; }
 
+#ifdef __GLIBC__
+  int AddFileStream(FileStream* stream);
+  void RemoveFileStream(int fd);
+
+  int IsReady(int nfds, fd_set* fds, bool (FileStream::*is_ready)(),
+    bool apply);
+  Cond& select_cond() { return select_cond_; }
+  Mutex& select_mutex() { return select_mutex_; }
+#endif // __GLIBC__
  private:
   struct FileDescriptor {
     // An index in open_files_ table
     int handle;
   };
 
+  // used for select() signals
+  Cond select_cond_;

[Dmitry Polukhin, 2012/05/30 15:13:32]

It is not good to mix direct pthread work and using wrappers, perhaps in this
particular case it is better to avoid using wrappers because nacl-mounts doesn't
use them.

[vissi, 2012/05/31 13:35:21]

Well, wrapper features (reentrancy) are used in the code, I suppose this can be
factored out later.

+  Mutex select_mutex_;
+
   struct FileHandle {
     Mount *mount;
+#ifdef __GLIBC__
+    FileStream* stream;
+#endif
     ino_t node;
     off_t offset;
     int flags;
     int use_count;
     pthread_mutex_t lock;
   };
+  FileHandle* GetFileHandle(int fd);
 
+#ifdef __GLIBC__
+  BaseSocketSubSystem* socket_subsystem_;
+#endif
   Path cwd_;
   int max_path_len_;
   MountManager mm_;
   pthread_mutex_t kp_lock_;
   static KernelProxy *kp_instance_;
 
   SlotAllocator<FileDescriptor> fds_;
   SlotAllocator<FileHandle> open_files_;
 
-  FileHandle *GetFileHandle(int fd);
   int OpenHandle(Mount *mount, const std::string& path, int oflag, mode_t mode);
 
   KernelProxy();
   static void Instantiate();
 };
 
 #endif  // PACKAGES_LIBRARIES_NACL_MOUNTS_BASE_KERNELPROXY_H_