glibc/sysdeps/unix/sysv/linux/nscd_setup_thread.c
Jakub Jelinek 0ecb606cb6 2.5-18.1
2007-07-12 18:26:36 +00:00

50 lines
1.9 KiB
C

/* Setup of nscd worker threads. Linux verison.
Copyright (C) 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <string.h>
#include <unistd.h>
#include <nscd.h>
#include <sysdep.h>
void
setup_thread (struct database_dyn *db)
{
#ifdef __NR_set_tid_address
/* Only supported when NPTL is used. */
char buf[100];
if (confstr (_CS_GNU_LIBPTHREAD_VERSION, buf, sizeof (buf)) >= sizeof (buf)
|| strncmp (buf, "NPTL", 4) != 0)
return;
/* Do not try this at home, kids. We play with the SETTID address
even thought the process is multi-threaded. This can only work
since none of the threads ever terminates. */
INTERNAL_SYSCALL_DECL (err);
int r = INTERNAL_SYSCALL (set_tid_address, err, 1,
&db->head->nscd_certainly_running);
if (!INTERNAL_SYSCALL_ERROR_P (r, err))
/* We know the kernel can reset this field when nscd terminates.
So, set the field to a nonzero value which indicates that nscd
is certainly running and clients can skip the test. */
db->head->nscd_certainly_running = 1;
#endif
}