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/* $Id: fdlimit.c 4511 2001-02-07 23:41:08Z rra $
**
** Portably determine or set the limit on open file descriptors.
**
** Pretty much all platforms these days have getrlimit and setrlimit, so
** prefer those, but for determining the current limit preserve the old
** portability (if we don't have getrlimit, try sysconf, then
** getdtablesize, then ulimit, and then try to find a hard-coded constant
** in <sys/param.h> and failing that fall back to the POSIX-guaranteed
** minimum of 20.
**
** For setting the limit, only setrlimit is supported; if it isn't
** available, return -1 always. We also refuse to set the limit to
** something higher than select can handle, checking against FD_SETSIZE.
**
** Note that on some versions of Linux (2.2.x reported), sysconf may return
** the wrong value for the maximum file descriptors. getrlimit is correct,
** so always prefer it.
*/
#include "config.h"
#include "clibrary.h"
#include <errno.h>
#if HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
/* FreeBSD 3.4 RELEASE needs <sys/time.h> before <sys/resource.h>. */
#if HAVE_GETRLIMIT || HAVE_SETRLIMIT
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# endif
# include <sys/resource.h>
#endif
#include "libinn.h"
#if HAVE_SETRLIMIT && defined(RLIMIT_NOFILE)
int
setfdlimit(unsigned int limit)
{
struct rlimit rl;
#ifdef FD_SETSIZE
if (limit > FD_SETSIZE) {
errno = EINVAL;
return -1;
}
#endif
rl.rlim_cur = 0;
rl.rlim_max = 0;
#if HAVE_GETRLIMIT
if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
rl.rlim_cur = 0;
rl.rlim_max = 0;
}
#endif
rl.rlim_cur = limit;
if (limit > rl.rlim_max)
rl.rlim_max = limit;
return setrlimit(RLIMIT_NOFILE, &rl);
}
#else /* !(HAVE_SETRLIMIT && RLIMIT_NOFILE) */
int
setfdlimit(unsigned int limit UNUSED)
{
/* Unimplemented system call is close enough. */
errno = ENOSYS;
return -1;
}
#endif /* !(HAVE_SETRLIMIT && RLIMIT_NOFILE) */
#if HAVE_GETRLIMIT && defined(RLIMIT_NOFILE)
int
getfdlimit(void)
{
struct rlimit rl;
if (getrlimit(RLIMIT_NOFILE, &rl) < 0)
return -1;
return rl.rlim_cur;
}
#elif HAVE_SYSCONF
int
getfdlimit(void)
{
return sysconf(_SC_OPEN_MAX);
}
#elif HAVE_GETDTABLESIZE
int
getfdlimit(void)
{
return getdtablesize();
}
#elif HAVE_ULIMIT
int
getfdlimit(void)
{
# ifdef UL_GDESLIM
return ulimit(UL_GDESLIM, 0);
# else
return ulimit(4, 0);
# endif
}
#else /* no function mechanism available */
# if HAVE_LIMITS_H
# include <limits.h>
# endif
# include <sys/param.h>
int
getfdcount(void)
{
# ifdef NOFILE
return NOFILE;
# else
return 20;
# endif
}
#endif
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