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authorUlrich Drepper <drepper@redhat.com>1998-04-20 18:41:05 +0000
committerUlrich Drepper <drepper@redhat.com>1998-04-20 18:41:05 +0000
commit8619129f3f0d5a9db6208be5bae6c2a8c9ce61a5 (patch)
tree033b6528f39a85f12db9d0859dbd1b90c2906eee /sysdeps/generic/utmp_file.c
parentf1fa8b68f3e7623a3ef86dcd0c7d090ccf0389f5 (diff)
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Update.
1998-04-20 18:00 Ulrich Drepper <drepper@cygnus.com> * libc.map: Add __dgettext to GLIBC_2.0 and __libc_longjmp, and __libc_siglongjmp to GLIBC_2.1. * elf/dl-minimal.c (__assert_perror_fail): Don't use strerror, use __strerror_r. * iconv/Makefile: Don't run tests now. * iconv/iconv_prog.c (process_block): If loop is repeated, call iconv with correct output buffer. Major rewrite of the low-level gconv functionality. * iconv/gconv.c: Rewritten. * iconv/gconv.h: Likewise. * iconv/gconv_builtin.c: Likewise. * iconv/gconv_builtin.h: Likewise. * iconv/gconv_conf.c: Likewise. * iconv/gconv_int.h: Likewise. * iconv/gconv_open.c: Likewise. * iconv/gconv_simple.c: Likewise. * iconv/iconv.c: Likewise. * iconvdata/8bit-gap.c: Likewise. * iconvdata/8bit-generic.c: Likewise. * iconvdata/Makefile: Likewise. * iconvdata/big5.c: Likewise. * iconvdata/cns11643.c: Likewise. * iconvdata/cns11643.h: Likewise. * iconvdata/cns11643l1.c: Likewise. * iconvdata/cns11643l1.h: Likewise. * iconvdata/ebcdic-at-de-a.c: Likewise. * iconvdata/ebcdic-at-de.c: Likewise. * iconvdata/ebcdic-ca-fr.c: Likewise. * iconvdata/euccn.c: Likewise. * iconvdata/eucjp.c: Likewise. * iconvdata/euckr.c: Likewise. * iconvdata/euctw.c: Likewise. * iconvdata/gb2312.c: Likewise. * iconvdata/gb2312.h: Likewise. * iconvdata/hp-roman8.c: Likewise. * iconvdata/iso646.c: Likewise. * iconvdata/iso6937.c: Likewise. * iconvdata/iso8859-1.c: Likewise. * iconvdata/iso8859-10.c: Likewise. * iconvdata/iso8859-2.c: Likewise. * iconvdata/iso8859-3.c: Likewise. * iconvdata/iso8859-4.c: Likewise. * iconvdata/iso8859-5.c: Likewise. * iconvdata/iso8859-6.c: Likewise. * iconvdata/iso8859-7.c: Likewise. * iconvdata/iso8859-8.c: Likewise. * iconvdata/iso8859-9.c: Likewise. * iconvdata/jis0201.c: Likewise. * iconvdata/jis0201.h: Likewise. * iconvdata/jis0208.c: Likewise. * iconvdata/jis0208.h: Likewise. * iconvdata/jis0212.c: Likewise. * iconvdata/jis0212.h: Likewise. * iconvdata/johab.c: Likewise. * iconvdata/koi-8.c: Likewise. * iconvdata/koi8-r.c: Likewise. * iconvdata/ksc5601.c: Likewise. * iconvdata/ksc5601.h: Likewise. * iconvdata/latin-greek-1.c: Likewise. * iconvdata/latin-greek.c: Likewise. * iconvdata/run-iconv-test.sh: Likewise. * iconvdata/sjis.c: Likewise. * iconvdata/t61.c: Likewise. * iconvdata/uhc.c: Likewise. * wcsmbs/btowc.c: Likewise. * wcsmbs/mbrtowc.c: Likewise. * wcsmbs/mbsnrtowcs.c: Likewise. * wcsmbs/mbsrtowcs.c: Likewise. * wcsmbs/wcrtomb.c: Likewise. * wcsmbs/wcsmbsload.c: Likewise. * wcsmbs/wcsnrtombs.c: Likewise. * wcsmbs/wcsrtombs.c: Likewise. * wcsmbs/wctob.c: Likewise. * iconv/loop.c: New file. * iconv/skeleton.c: New file. * stdlib/mblen.c: Handle empty input string correctly. * stdlib/mbtowc.c: Likewise. * posix/getopt.c: Various cleanups. * sysdeps/arm/bits/setjmp.h: Add copyright text. * sysdeps/i386/bits/setjmp.h: Likewise. * sysdeps/m68k/bits/setjmp.h: Likewise. * sysdeps/powerpc/bits/setjmp.h: Likewise. * sysdeps/sparc/sparc32/bits/setjmp.h: Likewise. * sysdeps/generic/longjmp.c: Rename function to __libc_siglongjmp and make longjmp weak alias. 1998-04-18 20:29 Philip Blundell <Philip.Blundell@pobox.com> * iconv/Makefile (routines): Only include gconv_dl if building for an ELF system - dynamic linking is not available on a.out. (CFLAGS-gconv_conf.c): Define STATIC_GCONV if omitting gconv_dl due to above check. * iconv/gconv_db.c: If STATIC_GCONV defined, don't try to call routines from gconv_dl. 1998-04-17 Gordon Matzigkeit <gord@profitpress.com> * csu/init.c (_IO_stdin_used): Protect with USE_IN_LIBIO so that we can compile without libio. 1998-04-20 16:28 Ulrich Drepper <drepper@cygnus.com> * sysdeps/mach/hurd/Subdirs: Remove login. 1998-04-11 Gordon Matzigkeit <gord@profitpress.com> * db2/compat.h: Include <errno.h>, to make sure we get the definition of EFTYPE before we define it ourselves. 1998-04-10 Gordon Matzigkeit <gord@profitpress.com> * sysdeps/generic/bits/socket.h: Protect against multiple inclusion. * sysdeps/mach/hurd/bits/ioctls.h: Likewise. Fix typo to allow inclusion from sys/ioctl.h again. 1998-04-16 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * iconvdata/*.[ch]: Clean up namespace. Optimize character lookup. 1998-04-16 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * libc.map: Export __strerror_r. Remove _strerror_internal. 1998-04-16 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * sysdeps/generic/strcasestr.c: Undefine strcasestr, not strstr. Also undefine __strcasestr. 1998-04-16 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * posix/regex.c: Rename __re_max_failures back to re_max_failures, aliases do not work with global variables due to copy relocations. 1998-04-20 15:12 Ulrich Drepper <drepper@cygnus.com> * manual/creature.texi: Fix type. Patch by Andreas Schwab. 1998-04-20 13:47 Ulrich Drepper <drepper@cygnus.com> * signal/sighold.c: Include stddef.h for NULL definition. * signal/sigrelse.c: Likewise. * sysdeps/posix/sigignore.c: Likewise. * sysdeps/posix/sigset.c: Likewise. * sysdeps/posix/waitid.c: Likewise. * sysdeps/unix/sysv/linux/rt_sigsuspend.c: Likewise. * sysdeps/unix/sysv/linux/rt_sigtimedwait.c: Likewise. * sysdeps/unix/sysv/linux/sigwaitinfo.c: Likewise. * wcsmbs/mbsrtowcs.c: Include stdlib.h for MB_CUR_MAX. Patch by Franz Sirl <Franz.Sirl-kernel@lauterbach.com>. 1998-04-13 Mark Kettenis <kettenis@phys.uva.nl> * login/Makefile (headers): Remove utmpx.h and bits/utmpx.h. * login/getutent.c (getutxent): Remove alias. * login/getutent_r.c (setutxent, pututxline, endutxent): Remove aliases. * login/getutid.c (getutxid): Remove alias. * login/getutline.c (getutxline): Remove alias. * login/utmp.h: Add prototypes for __updwtmp, __getutent, __getutid, __getutline and __pututline. * login/utmpx.h: Moved to ... * sysdeps/gnu/utmpx.h: ... here. [__USE_GNU]: Define UTMPX_FILE, UTMPX_FILENAME, WTMPX_FILE and WTMPX_FILENAME, declare utmpxname and updwtmpx. * login/updwtmp.c: Moved to ... * sysdeps/generic/updwtmp.c: ... here. (updwtmp): Generalized by allowing file name transformation. * sysdeps/gnu/updwtmp.c: New file. Use generic implementation with additional file name transformation. * sysdeps/unix/sysv/linux/updwtmp.c: Likewise. * login/utmp_file.c: Moved to ... * sysdeps/generic/utmp_file.c: ... here. (setutent_file): Generalized by allowing file name transformation. Do not print error message. Library functions should not print them. Reported by Jim Meyering. * sysdeps/gnu/utmp_file.c: New file. Use generic implementation with additional file name transformation. * sysdeps/unix/sysv/linux/utmp_file.c: Likewise. * sysdeps/gnu/Makefile [$(subdir)=login] (sysdep_routines): Add setutxent, getutxent, endutxent, getutxid, getutxid, getutxline, pututxline, utmpxname and updwtmpx. (sysdep_headers): Add utmpx.h and bits/utmpx.h. * sysdeps/gnu/bits/utmpx.h [__USE_GNU] Include paths.h. (_PATH_UTMPX): Define to _PATH_UTMP. (_PATH_WTMPX): Define to _PATH_WTMPX. (RUN_LVL): Define only if __USE_GNU. (ACCOUNTING): Define if __USE_GNU. * sysdeps/gnu/setutxent.c: New file. * sysdeps/gnu/getutxent.c: New file. * sysdeps/gnu/endutxent.c: New file. * sysdeps/gnu/getutxid.c: New file. * sysdeps/gnu/getutxline.c: New file. * sysdeps/gnu/pututxline.c: New file. * sysdeps/gnu/utmpxname.c: New file. * sysdeps/gnu/updwtmpx.c: New file. * sysdeps/unix/sysv/linux/paths.h (_PATH_UTMP_DB): Remove. * sysdeps/generic/bits/utmpx.h: Remove. 1998-04-20 Ulrich Drepper <drepper@cygnus.com> * posix/wordexp-test.c (main): Initialize ifs element of ts for ~root test. 1998-04-17 07:53 H.J. Lu <hjl@gnu.org> * sysdeps/unix/sysv/linux/i386/s_pread64.S: Fix a typo. 1998-04-17 11:32 Ulrich Drepper <drepper@cygnus.com> * libio/oldfileops.c (_IO_old_file_seekoff): Define temporary st variable using _G_stat64. * libio/fileops.c: Remove macro definition of fstat, it is in the global header. Reported by Thorsten Kukuk <kukuk@weber.uni-paderborn.de>. 1998-04-17 Philip Blundell <pb@nexus.co.uk> * sysdeps/arm/strlen.S: New file, based on code by Matthew Wilcox <willy@odie.barnet.ac.uk>. 1998-04-16 Philip Blundell <Philip.Blundell@pobox.com> * inet/netinet/in.h (IN6_IS_ADDR_MC_NODELOCAL): New macro, required by IPv6 Basic API. (IN6_IS_ADDR_MC_LINKLOCAL): Likewise. (IN6_IS_ADDR_MC_SITELOCAL): Likewise. (IN6_IS_ADDR_MC_ORGLOCAL): Likewise. (IN6_IS_ADDR_MC_GLOBAL): Likewise.
Diffstat (limited to 'sysdeps/generic/utmp_file.c')
-rw-r--r--sysdeps/generic/utmp_file.c472
1 files changed, 472 insertions, 0 deletions
diff --git a/sysdeps/generic/utmp_file.c b/sysdeps/generic/utmp_file.c
new file mode 100644
index 0000000000..08675185ce
--- /dev/null
+++ b/sysdeps/generic/utmp_file.c
@@ -0,0 +1,472 @@
+/* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>
+ and Paul Janzen <pcj@primenet.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 <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <utmp.h>
+
+#include "utmp-private.h"
+
+
+/* Descriptor for the file and position. */
+static int file_fd = -1;
+static off_t file_offset;
+
+/* Cache for the last read entry. */
+static struct utmp last_entry;
+
+
+/* Functions defined here. */
+static int setutent_file (void);
+static int getutent_r_file (struct utmp *buffer, struct utmp **result);
+static int getutid_r_file (const struct utmp *key, struct utmp *buffer,
+ struct utmp **result);
+static int getutline_r_file (const struct utmp *key, struct utmp *buffer,
+ struct utmp **result);
+static struct utmp *pututline_file (const struct utmp *data);
+static void endutent_file (void);
+static int updwtmp_file (const char *file, const struct utmp *utmp);
+
+/* Jump table for file functions. */
+struct utfuncs __libc_utmp_file_functions =
+{
+ setutent_file,
+ getutent_r_file,
+ getutid_r_file,
+ getutline_r_file,
+ pututline_file,
+ endutent_file,
+ updwtmp_file
+};
+
+
+#ifndef TRANSFORM_UTMP_FILE_NAME
+# define TRANSFORM_UTMP_FILE_NAME(file_name) (file_name)
+#endif
+
+static int
+setutent_file (void)
+{
+ if (file_fd < 0)
+ {
+ const char *file_name;
+
+ file_name = TRANSFORM_UTMP_FILE_NAME (__libc_utmp_file_name);
+
+ file_fd = open (file_name, O_RDWR);
+ if (file_fd == -1)
+ {
+ /* Hhm, read-write access did not work. Try read-only. */
+ file_fd = open (file_name, O_RDONLY);
+ if (file_fd == -1)
+ return 0;
+ }
+ }
+
+ lseek (file_fd, 0, SEEK_SET);
+ file_offset = 0;
+
+#if _HAVE_UT_TYPE - 0
+ /* Make sure the entry won't match. */
+ last_entry.ut_type = -1;
+#endif
+
+ return 1;
+}
+
+
+static int
+getutent_r_file (struct utmp *buffer, struct utmp **result)
+{
+ ssize_t nbytes;
+ struct flock fl; /* Information struct for locking. */
+
+ assert (file_fd >= 0);
+
+ if (file_offset == -1l)
+ {
+ /* Not available. */
+ *result = NULL;
+ return -1;
+ }
+
+ /* XXX The following is not perfect. Instead of locking the file itself
+ Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl> suggests to
+ use an extra locking file. */
+ /* XXX I think using an extra locking file does not solve the
+ problems. Instead we should set an alarm, which causes fcntl to
+ fail, as in ../nis/lckcache.c.
+ Mark Kettenis <kettenis@phys.uva.nl>. */
+
+ /* Try to get the lock. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_RDLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ /* Read the next entry. */
+ nbytes = read (file_fd, &last_entry, sizeof (struct utmp));
+
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (file_fd, F_SETLKW, &fl);
+
+ if (nbytes != sizeof (struct utmp))
+ {
+ file_offset = -1l;
+ *result = NULL;
+ return -1;
+ }
+
+ /* Update position pointer. */
+ file_offset += sizeof (struct utmp);
+
+ memcpy (buffer, &last_entry, sizeof (struct utmp));
+ *result = buffer;
+
+ return 0;
+}
+
+
+static int
+proc_utmp_eq (const struct utmp *entry, const struct utmp *match)
+{
+ return
+ (
+#if _HAVE_UT_TYPE - 0
+ (entry->ut_type == INIT_PROCESS
+ || entry->ut_type == LOGIN_PROCESS
+ || entry->ut_type == USER_PROCESS
+ || entry->ut_type == DEAD_PROCESS)
+ &&
+ (match->ut_type == INIT_PROCESS
+ || match->ut_type == LOGIN_PROCESS
+ || match->ut_type == USER_PROCESS
+ || match->ut_type == DEAD_PROCESS)
+ &&
+#endif
+#if _HAVE_UT_ID - 0
+ (entry->ut_id[0] && match->ut_id[0]
+ ? strncmp (entry->ut_id, match->ut_id, sizeof match->ut_id) == 0
+ : strncmp (entry->ut_line, match->ut_line, sizeof match->ut_line) == 0)
+#else
+ strncmp (entry->ut_line, match->ut_line, sizeof match->ut_line) == 0
+#endif
+ );
+}
+
+static int
+internal_getut_r (const struct utmp *id, struct utmp *buffer)
+{
+ int result = -1;
+ struct flock fl;
+
+ /* Try to get the lock. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_RDLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (file_fd, F_SETLKW, &fl);
+
+#if _HAVE_UT_TYPE - 0
+ if (id->ut_type == RUN_LVL || id->ut_type == BOOT_TIME
+ || id->ut_type == OLD_TIME || id->ut_type == NEW_TIME)
+ {
+ /* Search for next entry with type RUN_LVL, BOOT_TIME,
+ OLD_TIME, or NEW_TIME. */
+
+ while (1)
+ {
+ /* Read the next entry. */
+ if (read (file_fd, buffer, sizeof (struct utmp))
+ != sizeof (struct utmp))
+ {
+ __set_errno (ESRCH);
+ file_offset = -1l;
+ goto unlock_return;
+ }
+ file_offset += sizeof (struct utmp);
+
+ if (id->ut_type == buffer->ut_type)
+ break;
+ }
+ }
+ else
+#endif /* _HAVE_UT_TYPE */
+ {
+ /* Search for the next entry with the specified ID and with type
+ INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS. */
+
+ while (1)
+ {
+ /* Read the next entry. */
+ if (read (file_fd, buffer, sizeof (struct utmp))
+ != sizeof (struct utmp))
+ {
+ __set_errno (ESRCH);
+ file_offset = -1l;
+ goto unlock_return;
+ }
+ file_offset += sizeof (struct utmp);
+
+ if (proc_utmp_eq (buffer, id))
+ break;
+ }
+ }
+
+ result = 0;
+
+unlock_return:
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ return result;
+}
+
+
+/* For implementing this function we don't use the getutent_r function
+ because we can avoid the reposition on every new entry this way. */
+static int
+getutid_r_file (const struct utmp *id, struct utmp *buffer,
+ struct utmp **result)
+{
+ assert (file_fd >= 0);
+
+ if (file_offset == -1l)
+ {
+ *result = NULL;
+ return -1;
+ }
+
+ if (internal_getut_r (id, &last_entry) < 0)
+ {
+ *result = NULL;
+ return -1;
+ }
+
+ memcpy (buffer, &last_entry, sizeof (struct utmp));
+ *result = buffer;
+
+ return 0;
+}
+
+
+/* For implementing this function we don't use the getutent_r function
+ because we can avoid the reposition on every new entry this way. */
+static int
+getutline_r_file (const struct utmp *line, struct utmp *buffer,
+ struct utmp **result)
+{
+ struct flock fl;
+
+ assert (file_fd >= 0);
+
+ if (file_offset == -1l)
+ {
+ *result = NULL;
+ return -1;
+ }
+
+ /* Try to get the lock. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_RDLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (file_fd, F_SETLKW, &fl);
+
+ while (1)
+ {
+ /* Read the next entry. */
+ if (read (file_fd, &last_entry, sizeof (struct utmp))
+ != sizeof (struct utmp))
+ {
+ __set_errno (ESRCH);
+ file_offset = -1l;
+ *result = NULL;
+ goto unlock_return;
+ }
+ file_offset += sizeof (struct utmp);
+
+ /* Stop if we found a user or login entry. */
+ if (
+#if _HAVE_UT_TYPE - 0
+ (last_entry.ut_type == USER_PROCESS
+ || last_entry.ut_type == LOGIN_PROCESS)
+ &&
+#endif
+ !strncmp (line->ut_line, last_entry.ut_line, sizeof line->ut_line))
+ break;
+ }
+
+ memcpy (buffer, &last_entry, sizeof (struct utmp));
+ *result = buffer;
+
+unlock_return:
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ return ((*result == NULL) ? -1 : 0);
+}
+
+
+static struct utmp *
+pututline_file (const struct utmp *data)
+{
+ struct flock fl; /* Information struct for locking. */
+ struct utmp buffer;
+ struct utmp *pbuf;
+ int found;
+
+ assert (file_fd >= 0);
+
+ /* Find the correct place to insert the data. */
+ if (file_offset > 0
+ && (
+#if _HAVE_UT_TYPE - 0
+ (last_entry.ut_type == data->ut_type
+ && (last_entry.ut_type == RUN_LVL
+ || last_entry.ut_type == BOOT_TIME
+ || last_entry.ut_type == OLD_TIME
+ || last_entry.ut_type == NEW_TIME))
+ ||
+#endif
+ proc_utmp_eq (&last_entry, data)))
+ found = 1;
+ else
+ found = internal_getut_r (data, &buffer);
+
+ /* Try to lock the file. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_WRLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ if (found < 0)
+ {
+ /* We append the next entry. */
+ file_offset = lseek (file_fd, 0, SEEK_END);
+ if (file_offset % sizeof (struct utmp) != 0)
+ {
+ file_offset -= file_offset % sizeof (struct utmp);
+ __ftruncate (file_fd, file_offset);
+
+ if (lseek (file_fd, 0, SEEK_END) < 0)
+ {
+ pbuf = NULL;
+ goto unlock_return;
+ }
+ }
+ }
+ else
+ {
+ /* We replace the just read entry. */
+ file_offset -= sizeof (struct utmp);
+ lseek (file_fd, file_offset, SEEK_SET);
+ }
+
+ /* Write the new data. */
+ if (write (file_fd, data, sizeof (struct utmp)) != sizeof (struct utmp))
+ {
+ /* If we appended a new record this is only partially written.
+ Remove it. */
+ if (found < 0)
+ (void) __ftruncate (file_fd, file_offset);
+ pbuf = NULL;
+ }
+ else
+ {
+ file_offset += sizeof (struct utmp);
+ pbuf = (struct utmp *) data;
+ }
+
+ unlock_return:
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ return pbuf;
+}
+
+
+static void
+endutent_file (void)
+{
+ assert (file_fd >= 0);
+
+ close (file_fd);
+ file_fd = -1;
+}
+
+
+static int
+updwtmp_file (const char *file, const struct utmp *utmp)
+{
+ int result = -1;
+ struct flock fl;
+ off_t offset;
+ int fd;
+
+ /* Open WTMP file. */
+ fd = open (file, O_WRONLY);
+ if (fd < 0)
+ return -1;
+
+ /* Try to get the lock. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_WRLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (fd, F_SETLK, &fl);
+
+ /* Remember original size of log file. */
+ offset = lseek (fd, 0, SEEK_END);
+ if (offset % sizeof (struct utmp) != 0)
+ {
+ offset -= offset % sizeof (struct utmp);
+ __ftruncate (fd, offset);
+
+ if (lseek (fd, 0, SEEK_END) < 0)
+ goto unlock_return;
+ }
+
+ /* Write the entry. If we can't write all the bytes, reset the file
+ size back to the original size. That way, no partial entries
+ will remain. */
+ if (write (fd, utmp, sizeof (struct utmp)) != sizeof (struct utmp))
+ {
+ __ftruncate (fd, offset);
+ goto unlock_return;
+ }
+
+ result = 0;
+
+unlock_return:
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (fd, F_SETLKW, &fl);
+
+ /* Close WTMP file. */
+ close (fd);
+
+ return result;
+}