glibc/shadow/lckpwdf.c
Ulrich Drepper f8b87ef0d4 update from main archive 961211
Thu Dec 12 03:32:21 1996  Ulrich Drepper  <drepper@cygnus.com>

	* libio/_G_config.h: Add definition of _G_int16_t, _G_int32_t,
	_G_uint16_t, _G_uin32_t, _G_HAVE_BOOL, _G_HAVE_MMAP, and
	_G_ARGS.

	Change libio buffer handling to allocate internal buffers using
	mmap if possible.
	* libio/filedoalloc.c (_IO_file_doallocate): Change call to
	ALLOC_BUF.
	* libio/genops.c (_IO_setb, _IO_default_finish): Change call
	to FREE_BUF.
	(_IO_default_doallocate): Change call to ALLOC_BUF.
	* libio/libioP.h: Change definition of ALLOC_BUF and FREE_BUF
	to use mmap/munmap when possible.
	* libio/memstream.c: Don't use ALLOC_BUF, but directly malloc.
	* libio/vasprintf.c: Likewise.
	Patch by HJ Lu.

	* libio/libio.h: Define NULL as __null only for gcc-2.8 and up.
	* libio/libioP.h: Likewise.

	* libio/fileops.c (_IO_file_read, _IO_file_write): Don't
	restart syscall when EINTR was returned.  Necessary for POSIX.1.

	* libio/strops.c (_IO_str_overflow): Add cast to prevent warning.

	* new-malloc/malloc.c (heap_trim): Correctly place parentheses to
	prevent warnings.

	* nis/Makefile: Remove rules for bsd-tools which are not part
	of glibc.
	Patch by Thorsten Kukuk.

	* nis/ypclnt.c: Add prototype for xdr_free.
	Add const to first parameter for __yp_bind.
	* nis/nss_compat/compat-pwd.c (getpwent_next_netgr, getpwent_next_nis,
	getpwent_next_file): Variable `p2len' must have type size_t.
	* nis/nss_nis/nis-alias.c: Add casts to prevent warnings.
	* nis/nss_nis/nis-ethers.c: Likewise.
	* nis/nss_nis/nis-grp.c: Likewise.
	* nis/nss_nis/nis-hosts.c: Likewise.
	* nis/nss_nis/nis-network.c: Likewise.
	* nis/nss_nis/nis-proto.c: Likewise.
	* nis/nss_nis/nis-pwd.c: Likewise.
	* nis/nss_nis/nis-rpc.c: Likewise.
	* nis/nss_nis/nis-service.c: Likewise.
	* nis/nss_nis/nis-spwd.c: Likewise.

	* nis/rpcsvc/yp_prot.h (ypreq_key): Change type of members to
	`const char *'.
	(ypmaplist): Change member names to `map' and `next' and provide
	#defines for old names.
	Patch by Thorsten Kukuk.

	* nss/nss_files/files-parse.c (parse_line, parse_list): Change
	type for `datalen' parameter to size_t.

	* shsdow/lckpwdf.c: Use fcntl forlocking, not flock.

	* stdio-common/printf.c [USE_IN_LIBIO]: Provide alias _IO_printf
	for printf.
	* stdio-common/sscanf.c [USE_IN_LIBIO]: Provide alias _IO_sscanf
	for sscanf.
	Patch by HJ Lu.

	* stdio-common/tmpfile.c: Update copyright.

	* stdio-common/vfscanf.c: Correctly handle EINTR error from fgetc
	function.
	Don't eat white space for `C' format.

	* stdlib/tst-strtol.c [~0UL != 0xffffffff]: Fix typo in test data.

	* sysdeps/generic/abort.c: Update copyright.  De-ANSI-declfy.
	* sysdeps/i386/abort.c: Removed.  This version does not use
	signal SIGABRT.

	* sysdeps/i386/fpu/__math.h: Define __NO_MATH_INLINES if not using
	gcc-2.8 or up.
	Patch by HJ Lu.

	* sysdeps/posix/tempname.c: Test for error but EEXIST after open
	call.  If EMFILE, ENFILE, or EINTR return with error.

Wed Dec 11 14:43:52 1996  Ulrich Drepper  <drepper@cygnus.com>

	* gnu-versions.h: Set _GNU_OBSTACK_INTERFACE_VERSION back to 1.
	We are compatible again.
	* new-malloc/obstack.h (struct obstack): Add back alloc_failed bit
	even though it is not used.
	* malloc/obstack.h: Likewise.
	* new-malloc/obstack.c (_obstack_begin, _obstack_begin_1): Initialize
	alloc_failed bit to 0.

	* time/strftime.c: Extend for Emacs' needs.  Recognize field width,
	%P format and `0' modifier.

Tue Dec 10 21:20:44 1996  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* Makerules (make-link): Don't discard exit codes of intermediate
	commands.  Always use rellns-sh if symbolic links are available.

Tue Dec 10 20:09:51 1996  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/unix/sysv/linux/netinet/in.h: Enclose #include
	<linux/in.h> in __BEGIN_DECLS/__END_DECLS to avoid linkage
	conflict of ntohs etc. in <asm/byteorder.h>.
1996-12-12 03:24:48 +00:00

186 lines
5.4 KiB
C

/* Handle locking of password file.
Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <fcntl.h>
#include <libc-lock.h>
#include <shadow.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <sys/file.h>
/* Name of the lock file. */
#define PWD_LOCKFILE "/etc/.pwd.lock"
/* How long to wait for getting the lock before returning with an
error. */
#define TIMEOUT 15 /* sec */
/* File descriptor for lock file. */
static int lock_fd = -1;
/* Prevent problems in multithreaded program by using mutex. */
__libc_lock_define_initialized (static, lock)
/* Prototypes for local functions. */
static void noop_handler __P ((int __sig));
/* We cannot simply return in error cases. We have to close the file
and perhaps restore the signal handler. */
#define RETURN_CLOSE_FD(code) \
do { \
if ((code) < 0 && lock_fd >= 0) \
{ \
close (lock_fd); \
lock_fd = -1; \
} \
__libc_lock_unlock (lock); \
return (code); \
} while (0)
#define RETURN_RESTORE_HANDLER(code) \
do { \
/* Restore old action handler for alarm. We don't need to know \
about the current one. */ \
sigaction (SIGALRM, &saved_act, NULL); \
RETURN_CLOSE_FD (code); \
} while (0)
#define RETURN_CLEAR_ALARM(code) \
do { \
/* Clear alarm. */ \
alarm (0); \
/* Restore old set of handled signals. We don't need to know \
about the current one.*/ \
sigprocmask (SIG_SETMASK, &saved_set, NULL); \
RETURN_RESTORE_HANDLER (code); \
} while (0)
int
__lckpwdf ()
{
int flags;
sigset_t saved_set; /* Saved set of caught signals. */
struct sigaction saved_act; /* Saved signal action. */
sigset_t new_set; /* New set of caught signals. */
struct sigaction new_act; /* New signal action. */
struct flock fl; /* Information struct for locking. */
int result;
if (lock_fd != -1)
/* Still locked by own process. */
return -1;
/* Prevent problems caused by multiple threads. */
__libc_lock_lock (lock);
lock_fd = open (PWD_LOCKFILE, O_WRONLY | O_CREAT, 0600);
if (lock_fd == -1)
/* Cannot create lock file. */
RETURN_CLOSE_FD (-1);
/* Make sure file gets correctly closed when process finished. */
flags = fcntl (lock_fd, F_GETFD, 0);
if (flags == -1)
/* Cannot get file flags. */
RETURN_CLOSE_FD (-1);
flags |= FD_CLOEXEC; /* Close on exit. */
if (fcntl (lock_fd, F_SETFD, flags) < 0)
/* Cannot set new flags. */
RETURN_CLOSE_FD (-1);
/* Now we have to get exclusive write access. Since multiple
process could try this we won't stop when it first fails.
Instead we set a timeout for the system call. Once the timer
expires it is likely that there are some problems which cannot be
resolved by waiting.
It is important that we don't change the signal state. We must
restore the old signal behaviour. */
memset (&new_act, '\0', sizeof (struct sigaction));
new_act.sa_handler = noop_handler;
sigfillset (&new_act.sa_mask);
new_act.sa_flags = 0ul;
/* Install new action handler for alarm and save old. */
if (sigaction (SIGALRM, &new_act, &saved_act) < 0)
/* Cannot install signal handler. */
RETURN_CLOSE_FD (-1);
/* Now make sure the alarm signal is not blocked. */
sigemptyset (&new_set);
sigaddset (&new_set, SIGALRM);
if (sigprocmask (SIG_UNBLOCK, &new_set, &saved_set) < 0)
RETURN_RESTORE_HANDLER (-1);
/* Start timer. If we cannot get the lock in the specified time we
get a signal. */
alarm (TIMEOUT);
/* Try to get the lock. */
memset (&fl, '\0', sizeof (struct flock));
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
result = fcntl (lock_fd, F_SETLKW, &fl);
RETURN_CLEAR_ALARM (result);
}
weak_alias (__lckpwdf, lckpwdf)
int
__ulckpwdf ()
{
int result;
if (lock_fd == -1)
/* There is no lock set. */
result = -1;
else
{
/* Prevent problems caused by multiple threads. */
__libc_lock_lock (lock);
result = close (lock_fd);
/* Mark descriptor as unused. */
lock_fd = -1;
/* Clear mutex. */
__libc_lock_unlock (lock);
}
return result;
}
weak_alias (__ulckpwdf, ulckpwdf)
static void
noop_handler (sig)
int sig;
{
/* We simply return which makes the `fcntl' call return with an error. */
}