Graphics Programs Reference
In-Depth Information
sin_size = sizeof(struct sockaddr_in);
new_sockfd = accept(sockfd, (struct sockaddr *)&client_addr, &sin_size);
}
These familiar socket functions can all be accessed with a single Linux
system call, aptly named
socketcall()
. This is syscall number 102, which has a
slightly cryptic manual page.
reader@hacking:~/booksrc $ grep socketcall /usr/include/asm-i386/unistd.h
#define __NR_socketcall 102
reader@hacking:~/booksrc $ man 2 socketcall
IPC(2) Linux Programmer's Manual IPC(2)
NAME
socketcall - socket system calls
SYNOPSIS
int socketcall(int call, unsigned long *args);
DESCRIPTION
socketcall() is a common kernel entry point for the socket system calls. call
determines which socket function to invoke. args points to a block containing
the actual arguments, which are passed through to the appropriate call.
User programs should call the appropriate functions by their usual
names. Only standard library implementors and kernel hackers need to
know about socketcall().
The possible call numbers for the first argument are listed in the
linux/net.h include file.
From /usr/include/linux/net.h
#define SYS_SOCKET 1 /* sys_socket(2) */
#define SYS_BIND 2 /* sys_bind(2) */
#define SYS_CONNECT 3 /* sys_connect(2) */
#define SYS_LISTEN 4 /* sys_listen(2) */
#define SYS_ACCEPT 5 /* sys_accept(2) */
#define SYS_GETSOCKNAME 6 /* sys_getsockname(2) */
#define SYS_GETPEERNAME 7 /* sys_getpeername(2) */
#define SYS_SOCKETPAIR 8 /* sys_socketpair(2) */
#define SYS_SEND 9 /* sys_send(2) */
#define SYS_RECV 10 /* sys_recv(2) */
#define SYS_SENDTO 11 /* sys_sendto(2) */
#define SYS_RECVFROM 12 /* sys_recvfrom(2) */
#define SYS_SHUTDOWN 13 /* sys_shutdown(2) */
#define SYS_SETSOCKOPT 14 /* sys_setsockopt(2) */
#define SYS_GETSOCKOPT 15 /* sys_getsockopt(2) */
#define SYS_SENDMSG 16 /* sys_sendmsg(2) */
#
define SYS_RECVMSG 17 /* sys_recvmsg(2) */
