c38dbb97aa
Currently, the BSD socket API is implemented in libc, translating the API calls to character driver operations underneath. This approach has several issues: - it is inefficient, as most character driver operations are specific to the socket type, thus requiring that each operation start by bruteforcing the socket protocol family and type of the given file descriptor using several system calls; - it requires that libc itself be changed every time system support for a new protocol is added; - various parts of the libc implementations violate the asynchronous signal safety POSIX requirements. In order to resolve all these issues at once, the plan is to turn the BSD socket calls into system calls, thus making the BSD socket API the "native" ABI, removing the complexity from libc and instead letting VFS deal with the socket calls. The overall change is going to break all networking functionality. In order to smoothen the transition, this patch introduces the fifteen new BSD socket system calls, and makes libc try these first before falling back on the old behavior. For now, the VFS implementations of the new calls fail such that libc will always use the fallback cases. Later on, when we introduce the actual implementation of the native BSD socket calls, all statically linked programs will automatically use the new ABI, thus limiting actual application breakage. In other words: by itself, this patch does nothing, except add a bit of transitional overhead that will disappear in the future. The largest part of the patch is concerned with adding full support for the new BSD socket system calls to trace(1) - this early addition has the advantage of making system call tracing output of several socket calls much more readable already. Both the system call interfaces and the trace(1) support have already been tested using code that will be committed later on. Change-Id: I3460812be50c78be662d857f9d3d6840f3ca917f
180 lines
2.8 KiB
C
180 lines
2.8 KiB
C
/*
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* IMPORTANT NOTICE: THIS FILE CONTAINS STUBS ONLY RIGHT NOW, TO ENABLE A
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* SEAMLESS TRANSITION TO THE NEW API FOR PROGRAMS STATICALLY LINKED TO LIBC!
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*
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* This file implements the upper socket layer of VFS: the BSD socket system
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* calls, and any associated file descriptor, file pointer, vnode, and file
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* system processing. In most cases, this layer will call into the lower
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* socket layer in order to send the request to a socket driver. Generic file
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* calls (e.g., read, write, ioctl, and select) are not implemented here, and
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* will directly call into the lower socket layer as well.
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*
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* The following table shows the system call numbers implemented in this file,
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* along with their request and reply message types. Each request layout
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* message type is prefixed with "m_lc_vfs_". Each reply layout message type
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* is prefixed with "m_vfs_lc_". For requests without a specific reply layout,
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* only the "m_type" message field is used in the reply message.
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*
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* Type Request layout Reply layout
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* ---- -------------- ------------
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* VFS_SOCKET socket
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* VFS_SOCKETPAIR socket fdpair
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* VFS_BIND sockaddr
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* VFS_CONNECT sockaddr
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* VFS_LISTEN listen
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* VFS_ACCEPT sockaddr socklen
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* VFS_SENDTO sendrecv
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* VFS_RECVFROM sendrecv socklen
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* VFS_SENDMSG sockmsg
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* VFS_RECVMSG sockmsg
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* VFS_SETSOCKOPT sockopt
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* VFS_GETSOCKOPT sockopt socklen
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* VFS_GETSOCKNAME sockaddr socklen
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* VFS_GETPEERNAME sockaddr socklen
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* VFS_SHUTDOWN shutdown
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*/
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#include "fs.h"
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#include <sys/socket.h>
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/*
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* Create a socket.
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*/
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int
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do_socket(void)
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{
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return EAFNOSUPPORT;
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}
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/*
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* Create a pair of connected sockets.
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*/
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int
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do_socketpair(void)
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{
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return EAFNOSUPPORT;
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}
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/*
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* Bind a socket to a local address.
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*/
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int
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do_bind(void)
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{
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return ENOTSOCK;
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}
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/*
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* Connect a socket to a remote address.
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*/
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int
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do_connect(void)
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{
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return ENOTSOCK;
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}
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/*
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* Put a socket in listening mode.
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*/
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int
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do_listen(void)
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{
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return ENOTSOCK;
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}
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/*
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* Accept a connection on a listening socket, creating a new socket.
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*/
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int
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do_accept(void)
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{
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return ENOTSOCK;
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}
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/*
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* Send a message on a socket.
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*/
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int
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do_sendto(void)
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{
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return ENOTSOCK;
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}
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/*
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* Receive a message from a socket.
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*/
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int
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do_recvfrom(void)
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{
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return ENOTSOCK;
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}
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/*
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* Send or receive a message on a socket using a message structure.
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*/
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int
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do_sockmsg(void)
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{
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return ENOTSOCK;
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}
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/*
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* Set socket options.
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*/
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int
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do_setsockopt(void)
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{
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return ENOTSOCK;
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}
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/*
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* Get socket options.
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*/
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int
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do_getsockopt(void)
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{
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return ENOTSOCK;
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}
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/*
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* Get the local address of a socket.
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*/
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int
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do_getsockname(void)
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{
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return ENOTSOCK;
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}
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/*
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* Get the remote address of a socket.
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*/
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int
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do_getpeername(void)
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{
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return ENOTSOCK;
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}
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/*
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* Shut down socket send and receive operations.
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*/
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int
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do_shutdown(void)
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{
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return ENOTSOCK;
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}
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