freebsd-skq/lib/libc/gen/daemon.c
kib 146b187d13 Switch libc from using _sig{procmask,action,suspend} symbols, which
are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.

Since e.g. _sigaction is not interposed by libthr, calling signal()
removes thr_sighandler() from the handler slot etc.  The result was
breaking signal semantic and rtld locking.

The added __libc_sigprocmask and other symbols are hidden, they are
not exported and cannot be called through PLT.  The setjmp/longjmp
functions for x86 were changed to use direct calls, and since
PIC_PROLOGUE only needed for functional PLT indirection on i386, it is
removed as well.

The PowerPC bug of calling the syscall directly in the setjmp/longjmp
implementation is kept as is.

Reported by:	Pete French <petefrench@ingresso.co.uk>
Tested by:	Michiel Boland <boland37@xs4all.nl>
Reviewed by:	jilles (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-08-29 14:25:01 +00:00

96 lines
2.8 KiB
C

/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)daemon.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include "un-namespace.h"
#include "libc_private.h"
int
daemon(int nochdir, int noclose)
{
struct sigaction osa, sa;
int fd;
pid_t newgrp;
int oerrno;
int osa_ok;
/* A SIGHUP may be thrown when the parent exits below. */
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_IGN;
sa.sa_flags = 0;
osa_ok = __libc_sigaction(SIGHUP, &sa, &osa);
switch (fork()) {
case -1:
return (-1);
case 0:
break;
default:
/*
* A fine point: _exit(0), not exit(0), to avoid triggering
* atexit(3) processing
*/
_exit(0);
}
newgrp = setsid();
oerrno = errno;
if (osa_ok != -1)
__libc_sigaction(SIGHUP, &osa, NULL);
if (newgrp == -1) {
errno = oerrno;
return (-1);
}
if (!nochdir)
(void)chdir("/");
if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
(void)_dup2(fd, STDIN_FILENO);
(void)_dup2(fd, STDOUT_FILENO);
(void)_dup2(fd, STDERR_FILENO);
if (fd > 2)
(void)_close(fd);
}
return (0);
}