/*
 * \brief  Facility for passing system-call arguments
 * \author Norman Feske
 * \date   2011-02-15
 *
 * The 'Sysio' data structure is shared between the noux environment
 * and the child. It is used to pass system-call arguments that would
 * traditionally be transferred via 'copy_from_user' and 'copy_to_user'.
 */

/*
 * Copyright (C) 2011-2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

#ifndef _INCLUDE__NOUX_SESSION__SYSIO_H_
#define _INCLUDE__NOUX_SESSION__SYSIO_H_

/* Genode includes */
#include <os/ring_buffer.h>
#include <util/misc_math.h>
#include <vfs/file_system.h>


#define SYSIO_DECL(syscall_name, args, results) \
	struct args syscall_name##_in; \
	struct results syscall_name##_out;


namespace Noux {
	using namespace Genode;
	struct Sysio;
}


struct Noux::Sysio
{
    /* signal numbers must match with libc signal numbers */
	enum Signal {
		SIG_INT   = 2,
		SIG_CHLD  = 20,
		SIG_WINCH = 28
	};

	enum { SIGNAL_QUEUE_SIZE = 32 };
	Ring_buffer<enum Signal, SIGNAL_QUEUE_SIZE,
	            Ring_buffer_unsynchronized> pending_signals;

	enum { MAX_PATH_LEN = 512 };
	typedef char Path[MAX_PATH_LEN];

	enum { CHUNK_SIZE = 64*1024 };
	typedef char Chunk[CHUNK_SIZE];

	enum { ARGS_MAX_LEN = 16*1024 };
	typedef char Args[ARGS_MAX_LEN];

	enum { ENV_MAX_LEN  = 6*1024 };
	typedef char Env[ENV_MAX_LEN];

	typedef __SIZE_TYPE__ size_t;
	typedef long int ssize_t;

	/**
	 * Flags of 'mode' argument of open syscall
	 */
	enum {
		OPEN_MODE_RDONLY  = 0,
		OPEN_MODE_WRONLY  = 1,
		OPEN_MODE_RDWR    = 2,
		OPEN_MODE_ACCMODE = 3,
		OPEN_MODE_CREATE  = 0x0800, /* libc O_EXCL */
	};

	/**
	 * These values are the same as in the FreeBSD libc
	 */
	enum {
		STAT_MODE_SYMLINK   = 0120000,
		STAT_MODE_FILE      = 0100000,
		STAT_MODE_DIRECTORY = 0040000,
		STAT_MODE_CHARDEV   = 0020000,
		STAT_MODE_BLOCKDEV  = 0060000,
	};

	/*
	 * Must be POD (in contrast to the VFS type) because it's used in a union
	 */
	struct Stat
	{
		Vfs::file_size size;
		unsigned       mode;
		unsigned       uid;
		unsigned       gid;
		unsigned long  inode;
		unsigned long  device;

		Stat & operator= (Vfs::Directory_service::Stat const &stat)
		{
			size   = stat.size;
			mode   = stat.mode;
			uid    = stat.uid;
			gid    = stat.gid;
			inode  = stat.inode;
			device = stat.device;

			return *this;
		}
	};

	/**
	 * Argument structure used for ioctl syscall
	 */
	struct Ioctl_in
	{
		typedef Vfs::File_io_service::Ioctl_opcode Opcode;

		typedef Vfs::File_io_service::Ioctl_value Value;

		Opcode request;
		int argp;
	};

	/**
	 * Structure carrying the result values of 'ioctl' syscalls
	 */
	typedef Vfs::File_io_service::Ioctl_out Ioctl_out;

	enum Lseek_whence { LSEEK_SET, LSEEK_CUR, LSEEK_END };

	enum { DIRENT_MAX_NAME_LEN = Vfs::Directory_service::DIRENT_MAX_NAME_LEN };

	typedef Vfs::Directory_service::Dirent_type Dirent_type;

	/*
	 * Must be POD (in contrast to the VFS type) because it's used in a union
	 */
	struct Dirent
	{
		unsigned long fileno;
		Dirent_type   type;
		char          name[DIRENT_MAX_NAME_LEN];

		Dirent & operator= (Vfs::Directory_service::Dirent const &dirent)
		{
			fileno = dirent.fileno;
			type   = dirent.type;
			memcpy(name, dirent.name, DIRENT_MAX_NAME_LEN);

			return *this;
		}
	};

	enum Fcntl_cmd {
		FCNTL_CMD_GET_FILE_STATUS_FLAGS,
		FCNTL_CMD_SET_FILE_STATUS_FLAGS,
		FCNTL_CMD_SET_FD_FLAGS,
		FCNTL_CMD_GET_FD_FLAGS
	};

	enum {
		FCNTL_FILE_STATUS_FLAG_NONBLOCK = 4
	};

	/**
	 * Input and output argument type of select syscall
	 */
	struct Select_fds
	{
		/**
		 * Maximum number of file descriptors supported
		 */
		enum { MAX_FDS = 32U };

		/**
		 * Number of file descriptors to watch for read operations (rd),
		 * write operations (wr), or exceptions (ex).
		 */
		size_t num_rd,
		       num_wr,
		       num_ex;

		/**
		 * Array containing the file descriptors, starting with those
		 * referring to rd, followed by wr, and finally ex
		 */
		int array[MAX_FDS];

		/**
		 * Return total number of file descriptors contained in the array
		 */
		size_t total_fds() const {
			return min(num_rd + num_wr + num_ex, (size_t)MAX_FDS); }

		/**
		 * Check for maximum population of fds array
		 */
		bool max_fds_exceeded() const
		{
			/*
			 * Note that even though the corner case of num_rd + num_wr +
			 * num_ex == MAX_FDS is technically valid, this condition hints
			 * at a possible attempt to over popupate the array (see the
			 * implementation of 'select' in the Noux libc plugin). Hence,
			 * we regard this case as an error, too.
			 */
			return total_fds() >= MAX_FDS;
		}

		/**
		 * Return true of fd set index should be watched for reading
		 */
		bool watch_for_rd(unsigned i) const { return i < num_rd; }

		/**
		 * Return true if fd set index should be watched for writing
		 */
		bool watch_for_wr(unsigned i) const {
			return (i >= num_rd) && (i < num_rd + num_wr); }

		/**
		 * Return true if fd set index should be watched for exceptions
		 */
		bool watch_for_ex(unsigned i) const {
			return (i >= num_rd + num_wr) && (i < total_fds()); }
	};

	struct Select_timeout
	{
		long sec, usec;

		/**
		 * Set timeout to infinity
		 */
		void set_infinite() { sec = -1; usec = -1; }

		/**
		 * Return true if the timeout is infinite
		 */
		bool infinite() const { return (sec == -1) && (usec == -1); }

		/**
		 * Return true if the timeout is zero
		 */
		bool zero() const { return (sec == 0) && (usec == 0); }
	};

	/**
	 * Socket related structures
	 */
	enum { MAX_HOSTNAME_LEN = 255 };
	typedef char Hostname[MAX_HOSTNAME_LEN];

	enum { MAX_SERVNAME_LEN = 255 };
	typedef char Servname[MAX_SERVNAME_LEN];

	enum { MAX_ADDRINFO_RESULTS = 4 };

	struct in_addr
	{
		unsigned int    s_addr;
	};

	struct sockaddr
	{
		unsigned char   sa_len;
		unsigned char   sa_family;
		char            sa_data[14];
	};

	struct sockaddr_in {
		unsigned char   sin_len;
		unsigned char   sin_family;
		unsigned short  sin_port;
		struct          in_addr sin_addr;
		char            sin_zero[8];
	};

	typedef unsigned        socklen_t;

	struct addrinfo {
		int              ai_flags;
		int              ai_family;
		int              ai_socktype;
		int              ai_protocol;
		socklen_t        ai_addrlen;
		struct sockaddr *ai_addr;
		char            *ai_canonname;
		struct addrinfo *ai_next;
	};

	struct Addrinfo {
		struct addrinfo  addrinfo;
		struct sockaddr  ai_addr;
		char             ai_canonname[255];
	};

	/**
	 * user info defintions
	 */
	enum { USERINFO_GET_ALL = 0, USERINFO_GET_UID, USERINFO_GET_GID };
	enum { MAX_USERNAME_LEN = 32 };
	typedef char User[MAX_USERNAME_LEN];
	enum { MAX_SHELL_LEN = 16 };
	typedef char Shell[MAX_SHELL_LEN];
	enum { MAX_HOME_LEN = 128 };
	typedef char Home[MAX_HOME_LEN];
	typedef unsigned int Uid;

	/**
	 * time/clock definitions
	 */
	enum Clock_Id        { CLOCK_ID_SECOND };

	enum Fcntl_error     { FCNTL_ERR_CMD_INVALID = Vfs::Directory_service::NUM_GENERAL_ERRORS };
	enum Mkdir_error     { MKDIR_ERR_EXISTS,   MKDIR_ERR_NO_ENTRY,
	                       MKDIR_ERR_NO_SPACE, MKDIR_ERR_NO_PERM,
	                       MKDIR_ERR_NAME_TOO_LONG };
	enum Readlink_error  { READLINK_ERR_NO_ENTRY, READLINK_ERR_NO_PERM };
	enum Symlink_error   { SYMLINK_ERR_EXISTS,   SYMLINK_ERR_NO_ENTRY,
	                       SYMLINK_ERR_NO_SPACE, SYMLINK_ERR_NO_PERM,
	                       SYMLINK_ERR_NAME_TOO_LONG };

	enum Execve_error    { EXECVE_ERR_NO_ENTRY = Vfs::Directory_service::NUM_GENERAL_ERRORS,
	                       EXECVE_ERR_NO_MEMORY,
	                       EXECVE_ERR_NO_EXEC,
	                       EXECVE_ERR_ACCESS};
	enum Fork_error      { FORK_NOMEM = Vfs::Directory_service::NUM_GENERAL_ERRORS };
	enum Select_error    { SELECT_ERR_INTERRUPT };

	/**
	 * Socket related errors
	 */
	enum Accept_error    { ACCEPT_ERR_AGAIN, ACCEPT_ERR_WOULD_BLOCK,
	                       ACCEPT_ERR_INVALID, ACCEPT_ERR_NO_MEMORY,
	                       ACCEPT_ERR_NOT_SUPPORTED };

	enum Bind_error      { BIND_ERR_ACCESS, BIND_ERR_ADDR_IN_USE,
	                       BIND_ERR_INVALID, BIND_ERR_NO_MEMORY };

	enum Connect_error   { CONNECT_ERR_ACCESS, CONNECT_ERR_AGAIN,
	                       CONNECT_ERR_ALREADY, CONNECT_ERR_CONN_REFUSED,
	                       CONNECT_ERR_NO_PERM, CONNECT_ERR_ADDR_IN_USE,
	                       CONNECT_ERR_IN_PROGRESS, CONNECT_ERR_IS_CONNECTED,
	                       CONNECT_ERR_RESET, CONNECT_ERR_ABORTED,
	                       CONNECT_ERR_NO_ROUTE };

	enum Listen_error    { LISTEN_ERR_ADDR_IN_USE, LISTEN_ERR_NOT_SUPPORTED };

	enum Recv_error      { RECV_ERR_AGAIN, RECV_ERR_WOULD_BLOCK,
	                       RECV_ERR_CONN_REFUSED, RECV_ERR_INVALID,
	                       RECV_ERR_NOT_CONNECTED, RECV_ERR_NO_MEMORY };

	enum Send_error      { SEND_ERR_AGAIN, SEND_ERR_WOULD_BLOCK,
	                       SEND_ERR_CONNECTION_RESET, SEND_ERR_INVALID,
	                       SEND_ERR_IS_CONNECTED, SEND_ERR_NO_MEMORY };

	enum Shutdown_error  { SHUTDOWN_ERR_NOT_CONNECTED };

	enum Socket_error    { SOCKET_ERR_ACCESS, SOCKET_ERR_NO_AF_SUPPORT,
	                       SOCKET_ERR_INVALID, SOCKET_ERR_NO_MEMORY };

	enum Clock_error     { CLOCK_ERR_INVALID, CLOCK_ERR_FAULT, CLOCK_ERR_NO_PERM };

	enum Utimes_error    { UTIMES_ERR_ACCESS, UTIMES_ERR_FAUL, UTIMES_ERR_EIO,
	                       UTIMES_ERR_NAME_TOO_LONG, UTIMES_ERR_NO_ENTRY,
	                       UTIMES_ERR_NOT_DIRECTORY, UTIMES_ERR_NO_PERM,
	                       UTIMES_ERR_READ_ONLY };

	enum Wait4_error     { WAIT4_ERR_INTERRUPT };

	enum Kill_error      { KILL_ERR_SRCH };

	union {
		Vfs::Directory_service::General_error   general;
		Vfs::Directory_service::Stat_result     stat;
		Vfs::File_io_service::Ftruncate_result  ftruncate;
		Vfs::Directory_service::Open_result     open;
		Vfs::Directory_service::Unlink_result   unlink;
		Vfs::Directory_service::Rename_result   rename;
		Vfs::File_io_service::Read_result       read;
		Vfs::File_io_service::Write_result      write;
		Vfs::File_io_service::Ioctl_result      ioctl;

		Fcntl_error    fcntl;
		Mkdir_error    mkdir;
		Readlink_error readlink;
		Symlink_error  symlink;
		Execve_error   execve;
		Select_error   select;
		Accept_error   accept;
		Bind_error     bind;
		Connect_error  connect;
		Listen_error   listen;
		Recv_error     recv;
		Send_error     send;
		Shutdown_error shutdown;
		Socket_error   socket;
		Clock_error    clock;
		Utimes_error   utimes;
		Wait4_error    wait4;
		Kill_error     kill;
		Fork_error     fork;

	} error;

	union {

		SYSIO_DECL(write,       { int fd; size_t count; Chunk chunk; },
		                        { size_t count; });

		SYSIO_DECL(stat,        { Path path; }, { Stat st; });

		SYSIO_DECL(symlink,     { Path oldpath; Path newpath; }, { });

		SYSIO_DECL(fstat,       { int fd; }, { Stat st; });

		SYSIO_DECL(ftruncate,   { int fd; off_t length; }, { });

		SYSIO_DECL(fcntl,       { int fd; long long_arg; Fcntl_cmd cmd; },
		                        { int result; });

		SYSIO_DECL(open,        { Path path; int mode; }, { int fd; });

		SYSIO_DECL(close,       { int fd; }, { });

		SYSIO_DECL(ioctl,       : Ioctl_in { int fd; }, : Ioctl_out { });

		SYSIO_DECL(lseek,       { int fd; off_t offset; Lseek_whence whence; },
		                        { off_t offset; });

		SYSIO_DECL(dirent,      { int fd; }, { Dirent entry; });

		SYSIO_DECL(read,        { int fd; size_t count; },
		                        { Chunk chunk; size_t count; });

		SYSIO_DECL(readlink,    { Path path; size_t bufsiz; },
		                        { Chunk chunk; size_t count; });

		SYSIO_DECL(execve,      { Path filename; Args args; Env env; }, { });

		SYSIO_DECL(select,      { Select_fds fds; Select_timeout timeout; },
		                        { Select_fds fds; });

		SYSIO_DECL(fork,        { addr_t ip; addr_t sp;
		                          addr_t parent_cap_addr; },
		                        { int pid; });

		SYSIO_DECL(getpid,      { }, { int pid; });

		SYSIO_DECL(wait4,       { int pid; bool nohang; },
		                        { int pid; int status; });
		SYSIO_DECL(pipe,        { }, { int fd[2]; });

		SYSIO_DECL(dup2,        { int fd; int to_fd; }, { int fd; });

		SYSIO_DECL(unlink,      { Path path; }, { });

		SYSIO_DECL(rename,      { Path from_path; Path to_path; }, { });

		SYSIO_DECL(mkdir,       { Path path; int mode; }, { });

		SYSIO_DECL(socket,      { int domain; int type; int protocol; },
		                        { int fd; });

		 /* XXX for now abuse Chunk for passing optval */
		SYSIO_DECL(getsockopt,  { int fd; int level; int optname; Chunk optval;
		                          socklen_t optlen; }, { int result; });

		SYSIO_DECL(setsockopt,  { int fd; int level;
		                          int optname; Chunk optval;
		                          socklen_t optlen; }, { });

		SYSIO_DECL(accept,      { int fd; struct sockaddr addr; socklen_t addrlen; },
		                        { int fd; });

		SYSIO_DECL(bind,        { int fd; struct sockaddr addr;
		                          socklen_t addrlen; }, { int result; });

		SYSIO_DECL(getpeername, { int fd; struct sockaddr addr;
		                          socklen_t addrlen; }, { });

		SYSIO_DECL(listen,      { int fd; int type; int backlog; },
		                        { int result; });

		SYSIO_DECL(send,        { int fd; Chunk buf; size_t len; int flags; },
		                        { ssize_t len; });

		SYSIO_DECL(sendto,      { int fd; Chunk buf; size_t len; int flags;
		                          struct sockaddr dest_addr; socklen_t addrlen; },
		                        { ssize_t len; });

		SYSIO_DECL(recv,        { int fd; Chunk buf; size_t len; int flags; },
		                        { size_t len; });

		SYSIO_DECL(recvfrom,    { int fd; Chunk buf; size_t len; int flags;
		                          struct sockaddr src_addr; socklen_t addrlen; },
		                        { size_t len; });

		SYSIO_DECL(shutdown,    { int fd; int how; }, { });

		SYSIO_DECL(connect,     { int fd; struct sockaddr addr; socklen_t addrlen; },
		                        { int result; });

		SYSIO_DECL(userinfo, { int request; Uid uid; },
		                     { User name; Uid uid; Uid gid; Shell shell;
		                       Home home; });

		SYSIO_DECL(gettimeofday, { }, { unsigned long sec; unsigned int usec; });

		SYSIO_DECL(clock_gettime, { Clock_Id clock_id; },
		                          { unsigned long sec; unsigned long nsec; });

		SYSIO_DECL(utimes,      { Path path; unsigned long sec; unsigned long usec; },
		                        { });

		SYSIO_DECL(sync,        { }, { });

		SYSIO_DECL(kill,        { int pid; Signal sig; }, { });

		SYSIO_DECL(getdtablesize, { }, { int n; });
	};
};

#undef SYSIO_DECL

#endif /* _INCLUDE__NOUX_SESSION__SYSIO_H_ */