File: nscd_setup_thread.c

package info (click to toggle)
glibc 2.24-10
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 223,412 kB
  • sloc: ansic: 991,967; asm: 261,800; sh: 10,385; makefile: 9,710; cpp: 4,169; python: 3,971; perl: 2,254; awk: 1,753; pascal: 1,521; yacc: 291; sed: 80
file content (49 lines) | stat: -rw-r--r-- 1,829 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
/* Setup of nscd worker threads.  Linux verison.
   Copyright (C) 2004-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published
   by the Free Software Foundation; version 2 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.  */

#include <string.h>
#include <unistd.h>
#include <nscd.h>
#include <sysdep.h>


int
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 0;

  /* 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.  */
    return db->head->nscd_certainly_running = 1;
#endif

  return 0;
}