ef8f52ad53
select() returns EINVAL if you try to feed it a value of FD_SETSIZE greater that 256. You can apparently adjust this by specifying a larger value of FD_SETSIZE when configuring your kernel. However, if you set the maximum number of open file descriptors per process to some value greater than the FD_SETSIZE value that select() expects, many selects() within the RPC library code will be botched because _rpc_dtablesize() will return invalid numbers. This is to say that it will return the upper descriptor table size limit which can be much higher than 256. Unless select() is prepared to expect this 'unusually' high value, it will fail. (A good example of this can be seen with NIS enabled: if you type 'unlimit' at the shell prompt and then run any command that does NIS calls, you'll be bombarded with errors from clnttcp_create().) A temporary fix for this is to clamp the value returned by _rpc_dtablesize() at FD_SETSIZE (as defined in <sys/types.h> (256)). I suppose the Right Thing would be to provide some mechanism for select() to dynamically adjust itself to handle FD_SETSIZE values larger than 256, but it's a bit late in the game for that. Hopefully 256 file descriptors will be enough to keep RPC happy for now.
64 lines
2.3 KiB
C
64 lines
2.3 KiB
C
/*
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* Sun RPC is a product of Sun Microsystems, Inc. and is provided for
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* unrestricted use provided that this legend is included on all tape
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* media and as a part of the software program in whole or part. Users
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* may copy or modify Sun RPC without charge, but are not authorized
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* to license or distribute it to anyone else except as part of a product or
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* program developed by the user.
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*
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* SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
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* WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
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*
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* Sun RPC is provided with no support and without any obligation on the
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* part of Sun Microsystems, Inc. to assist in its use, correction,
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* modification or enhancement.
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*
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* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
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* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
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* OR ANY PART THEREOF.
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*
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* In no event will Sun Microsystems, Inc. be liable for any lost revenue
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* or profits or other special, indirect and consequential damages, even if
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* Sun has been advised of the possibility of such damages.
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*
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* Sun Microsystems, Inc.
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* 2550 Garcia Avenue
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* Mountain View, California 94043
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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/*static char *sccsid = "from: @(#)rpc_dtablesize.c 1.2 87/08/11 Copyr 1987 Sun Micro";*/
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/*static char *sccsid = "from: @(#)rpc_dtablesize.c 2.1 88/07/29 4.0 RPCSRC";*/
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static char *rcsid = "rpc_dtablesize.c,v 1.1 1994/08/07 18:36:02 wollman Exp";
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#endif
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#include <sys/types.h>
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/*
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* Cache the result of getdtablesize(), so we don't have to do an
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* expensive system call every time.
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*/
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/*
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* XXX In FreeBSD 2.x, you can have the maximum number of open file
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* descriptors be greater than FD_SETSIZE (which us 256 by default).
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* This can lead to many RPC functions getting back an EINVAL from
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* select() and bombing all over the place.
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*
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* You can apparently get select() to handle values larger than 256
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* by patching the kernel, but most people aren't likely to know
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* that. Clamping this function at 256 is a kludge, but it'll have to
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* do until select()'s descriptor table size can be adjusted dynamically.
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*/
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_rpc_dtablesize()
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{
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static int size;
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if (size == 0) {
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size = getdtablesize();
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if (size > FD_SETSIZE)
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size = FD_SETSIZE;
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}
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return (size);
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}
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