diff options
Diffstat (limited to 'nuttx/fs/fs_select.c')
| -rw-r--r-- | nuttx/fs/fs_select.c | 57 |
1 files changed, 44 insertions, 13 deletions
diff --git a/nuttx/fs/fs_select.c b/nuttx/fs/fs_select.c index e40c5bc13..206e73be0 100644 --- a/nuttx/fs/fs_select.c +++ b/nuttx/fs/fs_select.c @@ -1,7 +1,7 @@ /**************************************************************************** * fs/fs_select.c * - * Copyright (C) 2008-2009, 2012 Gregory Nutt. All rights reserved. + * Copyright (C) 2008-2009, 2012-2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt <gnutt@nuttx.org> * * Redistribution and use in source and binary forms, with or without @@ -109,9 +109,27 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds, int ndx; int ret; + /* How many pollfd structures do we need to allocate? */ + + /* Initialize the descriptor list for poll() */ + + for (fd = 0, npfds = 0; fd < nfds; fd++) + { + /* Check if any monitor operation is requested on this fd */ + + if (readfds && FD_ISSET(fd, readfds) || + writefds && FD_ISSET(fd, writefds) || + exceptfds && FD_ISSET(fd, exceptfds)) + { + /* Yes.. increment the count of pollfds structures needed */ + + npfds++; + } + } + /* Allocate the descriptor list for poll() */ - pollset = (struct pollfd *)kzalloc(nfds * sizeof(struct pollfd)); + pollset = (struct pollfd *)kzalloc(npfds * sizeof(struct pollfd)); if (!pollset) { set_errno(ENOMEM); @@ -120,7 +138,7 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds, /* Initialize the descriptor list for poll() */ - for (fd = 0, npfds = 0; fd < nfds; fd++) + for (fd = 0, ndx = 0; fd < nfds; fd++) { int incr = 0; @@ -133,9 +151,9 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds, if (readfds && FD_ISSET(fd, readfds)) { - pollset[npfds].fd = fd; - pollset[npfds].events |= POLLIN; - incr = 1; + pollset[ndx].fd = fd; + pollset[ndx].events |= POLLIN; + incr = 1; } /* The writefds set holds the set of FDs that the caller can be assured @@ -144,25 +162,38 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds, if (writefds && FD_ISSET(fd, writefds)) { - pollset[npfds].fd = fd; - pollset[npfds].events |= POLLOUT; - incr = 1; + pollset[ndx].fd = fd; + pollset[ndx].events |= POLLOUT; + incr = 1; } /* The exceptfds set holds the set of FDs that are watched for exceptions */ if (exceptfds && FD_ISSET(fd, exceptfds)) { - pollset[npfds].fd = fd; - incr = 1; + pollset[ndx].fd = fd; + incr = 1; } - npfds += incr; + ndx += incr; } + DEBUGASSERT(ndx == npfds); + /* Convert the timeout to milliseconds */ - msec = timeout->tv_sec * 1000 + timeout->tv_usec / 1000; + if (timeout) + { + /* Calculate the timeout in milliseconds */ + + msec = timeout->tv_sec * 1000 + timeout->tv_usec / 1000; + } + else + { + /* Any negative value of msec means no timeout */ + + msec = -1; + } /* Then let poll do all of the real work. */ |