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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [libnetworking/] [rtems/] [rtems_select.c] - Rev 30
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/* * $Id: rtems_select.c,v 1.2 2001-09-27 12:02:00 chris Exp $ */ #include <string.h> #include <stdarg.h> /* #include <stdlib.h> */ #include <stdio.h> #include <rtems.h> #include <rtems/libio.h> #include <rtems/error.h> #include <rtems/rtems_bsdnet.h> #include <sys/errno.h> #include <sys/fcntl.h> #include <sys/types.h> #include <sys/param.h> #include <sys/mbuf.h> #include <sys/socket.h> #include <sys/socketvar.h> #include <sys/protosw.h> #include <sys/proc.h> #include <sys/filio.h> #include <net/if.h> #include <net/route.h> /* ********************************************************************* * RTEMS implementation of select() system call * ********************************************************************* */ /* * This implementation is quite restricted: * Works on sockets only -- no support for other devices! * A given socket can be in a read-select or a read/recv* by only * one task at a time. * A given socket can be in a write-select or a write/send* by only * one task at a time. * * NOTE - select() is a very expensive system call. It should be avoided * if at all possible. In many cases, rewriting the application * to use multiple tasks (one per socket) is a better solution. */ static __inline int imin(int a, int b) { return (a < b ? a : b); } struct socket *rtems_bsdnet_fdToSocket(int fd); static int socket_select (struct socket *so, int which, rtems_id tid) { switch (which) { case FREAD: if (soreadable(so)) return (1); so->so_rcv.sb_flags |= SB_WAIT; so->so_rcv.sb_sel.si_pid = tid; break; case FWRITE: if (sowriteable(so)) return (1); so->so_rcv.sb_flags |= SB_WAIT; so->so_snd.sb_sel.si_pid = tid; break; case 0: if (so->so_oobmark || (so->so_state & SS_RCVATMARK)) return (1); so->so_rcv.sb_sel.si_pid = tid; break; } return (0); } static int selscan (rtems_id tid, fd_mask **ibits, fd_mask **obits, int nfd, int *retval) { struct socket *so; int msk, i, fd; fd_mask bits, bit; int n = 0; static int flag[3] = { FREAD, FWRITE, 0 }; for (msk = 0; msk < 3; msk++) { if (ibits[msk] == NULL) continue; for (i = 0; i < nfd; i += NFDBITS) { bits = ibits[msk][i/NFDBITS]; for (fd = i, bit = 1 ; bits && (fd < nfd) ; fd++, bit <<= 1) { if ((bits & bit) == 0) continue; bits &= ~bit; so = rtems_bsdnet_fdToSocket (fd); if (so == NULL) return (EBADF); if (socket_select (so, flag[msk], tid)) { obits[msk][fd/NFDBITS] |= (1 << (fd % NFDBITS)); n++; } } } } *retval = n; return (0); } int select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *tv) { fd_mask *ibits[3], *obits[3]; fd_set ob[3]; int error, timo; int retval; rtems_id tid; rtems_interval then, now; rtems_event_set events; if (nfds < 0) return (EINVAL); if (tv) { timo = tv->tv_sec * hz + tv->tv_usec / tick; if (timo == 0) timo = 1; rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &then); } else { timo = 0; } #define getbits(name,i) if (name) { \ ibits[i] = &name->fds_bits[0]; \ obits[i] = &ob[i].fds_bits[0]; \ FD_ZERO(&ob[i]); \ } \ else ibits[i] = NULL getbits (readfds, 0); getbits (writefds, 1); getbits (exceptfds, 2); #undef getbits rtems_task_ident (RTEMS_SELF, 0, &tid); rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_NO_WAIT, RTEMS_NO_TIMEOUT, &events); for (;;) { rtems_bsdnet_semaphore_obtain (); error = selscan(tid, ibits, obits, nfds, &retval); rtems_bsdnet_semaphore_release (); if (error || retval) break; if (timo) { rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &now); timo -= now - then; if (timo <= 0) break; then = now; } rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_WAIT, timo, &events); } #define putbits(name,i) if (name) *name = ob[i] putbits (readfds, 0); putbits (writefds, 1); putbits (exceptfds, 2); #undef putbits if (error) { errno = error; retval = -1; } return (retval); }
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