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41bdb6e20c
2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
483 lines
12 KiB
C
483 lines
12 KiB
C
/* Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>
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and Paul Janzen <pcj@primenet.com>, 1996.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <utmp.h>
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#include "utmp-private.h"
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/* Descriptor for the file and position. */
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static int file_fd = -1;
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static off64_t file_offset;
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/* Cache for the last read entry. */
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static struct utmp last_entry;
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/* Locking timeout. */
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#ifndef TIMEOUT
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# define TIMEOUT 1
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#endif
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/* Do-nothing handler for locking timeout. */
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static void timeout_handler (int signum) {};
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#define LOCK_FILE(fd, type) \
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{ \
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struct flock fl; \
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struct sigaction action, old_action; \
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unsigned int old_timeout; \
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\
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/* Cancel any existing alarm. */ \
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old_timeout = alarm (0); \
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\
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/* Establish signal handler. */ \
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action.sa_handler = timeout_handler; \
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sigemptyset (&action.sa_mask); \
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action.sa_flags = 0; \
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__sigaction (SIGALRM, &action, &old_action); \
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\
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alarm (TIMEOUT); \
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\
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/* Try to get the lock. */ \
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memset (&fl, '\0', sizeof (struct flock)); \
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fl.l_type = (type); \
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fl.l_whence = SEEK_SET; \
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__fcntl ((fd), F_SETLKW, &fl)
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#define UNLOCK_FILE(fd) \
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/* Unlock the file. */ \
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fl.l_type = F_UNLCK; \
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__fcntl ((fd), F_SETLKW, &fl); \
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\
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/* Reset the signal handler and alarm. */ \
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__sigaction (SIGALRM, &old_action, NULL); \
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alarm (old_timeout); \
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} while (0)
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/* Functions defined here. */
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static int setutent_file (void);
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static int getutent_r_file (struct utmp *buffer, struct utmp **result);
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static int getutid_r_file (const struct utmp *key, struct utmp *buffer,
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struct utmp **result);
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static int getutline_r_file (const struct utmp *key, struct utmp *buffer,
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struct utmp **result);
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static struct utmp *pututline_file (const struct utmp *data);
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static void endutent_file (void);
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static int updwtmp_file (const char *file, const struct utmp *utmp);
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/* Jump table for file functions. */
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struct utfuncs __libc_utmp_file_functions =
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{
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setutent_file,
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getutent_r_file,
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getutid_r_file,
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getutline_r_file,
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pututline_file,
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endutent_file,
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updwtmp_file
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};
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#ifndef TRANSFORM_UTMP_FILE_NAME
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# define TRANSFORM_UTMP_FILE_NAME(file_name) (file_name)
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#endif
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static int
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setutent_file (void)
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{
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if (file_fd < 0)
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{
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const char *file_name;
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int result;
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file_name = TRANSFORM_UTMP_FILE_NAME (__libc_utmp_file_name);
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file_fd = __open (file_name, O_RDWR);
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if (file_fd == -1)
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{
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/* Hhm, read-write access did not work. Try read-only. */
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file_fd = __open (file_name, O_RDONLY);
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if (file_fd == -1)
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return 0;
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}
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/* We have to make sure the file is `closed on exec'. */
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result = __fcntl (file_fd, F_GETFD, 0);
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if (result >= 0)
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result = __fcntl (file_fd, F_SETFD, result | FD_CLOEXEC);
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if (result == -1)
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{
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__close (file_fd);
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return 0;
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}
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}
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__lseek64 (file_fd, 0, SEEK_SET);
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file_offset = 0;
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#if _HAVE_UT_TYPE - 0
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/* Make sure the entry won't match. */
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last_entry.ut_type = -1;
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#endif
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return 1;
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}
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static int
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getutent_r_file (struct utmp *buffer, struct utmp **result)
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{
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ssize_t nbytes;
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assert (file_fd >= 0);
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if (file_offset == -1l)
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{
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/* Not available. */
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*result = NULL;
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return -1;
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}
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LOCK_FILE (file_fd, F_RDLCK);
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/* Read the next entry. */
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nbytes = __read (file_fd, &last_entry, sizeof (struct utmp));
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UNLOCK_FILE (file_fd);
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if (nbytes != sizeof (struct utmp))
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{
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file_offset = -1l;
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*result = NULL;
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return -1;
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}
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/* Update position pointer. */
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file_offset += sizeof (struct utmp);
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memcpy (buffer, &last_entry, sizeof (struct utmp));
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*result = buffer;
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return 0;
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}
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static int
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proc_utmp_eq (const struct utmp *entry, const struct utmp *match)
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{
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return
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(
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#if _HAVE_UT_TYPE - 0
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(entry->ut_type == INIT_PROCESS
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|| entry->ut_type == LOGIN_PROCESS
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|| entry->ut_type == USER_PROCESS
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|| entry->ut_type == DEAD_PROCESS)
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&&
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(match->ut_type == INIT_PROCESS
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|| match->ut_type == LOGIN_PROCESS
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|| match->ut_type == USER_PROCESS
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|| match->ut_type == DEAD_PROCESS)
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&&
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#endif
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#if _HAVE_UT_ID - 0
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(entry->ut_id[0] && match->ut_id[0]
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? strncmp (entry->ut_id, match->ut_id, sizeof match->ut_id) == 0
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: strncmp (entry->ut_line, match->ut_line, sizeof match->ut_line) == 0)
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#else
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strncmp (entry->ut_line, match->ut_line, sizeof match->ut_line) == 0
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#endif
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);
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}
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static int
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internal_getut_r (const struct utmp *id, struct utmp *buffer)
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{
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int result = -1;
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LOCK_FILE (file_fd, F_RDLCK);
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#if _HAVE_UT_TYPE - 0
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if (id->ut_type == RUN_LVL || id->ut_type == BOOT_TIME
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|| id->ut_type == OLD_TIME || id->ut_type == NEW_TIME)
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{
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/* Search for next entry with type RUN_LVL, BOOT_TIME,
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OLD_TIME, or NEW_TIME. */
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while (1)
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{
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/* Read the next entry. */
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if (__read (file_fd, buffer, sizeof (struct utmp))
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!= sizeof (struct utmp))
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{
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__set_errno (ESRCH);
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file_offset = -1l;
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goto unlock_return;
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}
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file_offset += sizeof (struct utmp);
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if (id->ut_type == buffer->ut_type)
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break;
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}
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}
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else
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#endif /* _HAVE_UT_TYPE */
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{
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/* Search for the next entry with the specified ID and with type
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INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS. */
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while (1)
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{
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/* Read the next entry. */
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if (__read (file_fd, buffer, sizeof (struct utmp))
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!= sizeof (struct utmp))
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{
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__set_errno (ESRCH);
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file_offset = -1l;
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goto unlock_return;
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}
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file_offset += sizeof (struct utmp);
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if (proc_utmp_eq (buffer, id))
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break;
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}
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}
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result = 0;
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unlock_return:
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UNLOCK_FILE (file_fd);
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return result;
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}
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/* For implementing this function we don't use the getutent_r function
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because we can avoid the reposition on every new entry this way. */
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static int
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getutid_r_file (const struct utmp *id, struct utmp *buffer,
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struct utmp **result)
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{
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assert (file_fd >= 0);
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if (file_offset == -1l)
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{
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*result = NULL;
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return -1;
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}
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if (internal_getut_r (id, &last_entry) < 0)
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{
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*result = NULL;
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return -1;
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}
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memcpy (buffer, &last_entry, sizeof (struct utmp));
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*result = buffer;
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return 0;
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}
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/* For implementing this function we don't use the getutent_r function
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because we can avoid the reposition on every new entry this way. */
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static int
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getutline_r_file (const struct utmp *line, struct utmp *buffer,
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struct utmp **result)
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{
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assert (file_fd >= 0);
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if (file_offset == -1l)
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{
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*result = NULL;
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return -1;
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}
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LOCK_FILE (file_fd, F_RDLCK);
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while (1)
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{
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/* Read the next entry. */
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if (__read (file_fd, &last_entry, sizeof (struct utmp))
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!= sizeof (struct utmp))
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{
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__set_errno (ESRCH);
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file_offset = -1l;
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*result = NULL;
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goto unlock_return;
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}
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file_offset += sizeof (struct utmp);
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/* Stop if we found a user or login entry. */
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if (
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#if _HAVE_UT_TYPE - 0
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(last_entry.ut_type == USER_PROCESS
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|| last_entry.ut_type == LOGIN_PROCESS)
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&&
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#endif
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!strncmp (line->ut_line, last_entry.ut_line, sizeof line->ut_line))
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break;
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}
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memcpy (buffer, &last_entry, sizeof (struct utmp));
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*result = buffer;
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unlock_return:
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UNLOCK_FILE (file_fd);
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return ((*result == NULL) ? -1 : 0);
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}
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static struct utmp *
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pututline_file (const struct utmp *data)
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{
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struct utmp buffer;
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struct utmp *pbuf;
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int found;
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assert (file_fd >= 0);
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/* Find the correct place to insert the data. */
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if (file_offset > 0
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&& (
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#if _HAVE_UT_TYPE - 0
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(last_entry.ut_type == data->ut_type
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&& (last_entry.ut_type == RUN_LVL
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|| last_entry.ut_type == BOOT_TIME
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|| last_entry.ut_type == OLD_TIME
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|| last_entry.ut_type == NEW_TIME))
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||
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#endif
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proc_utmp_eq (&last_entry, data)))
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found = 1;
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else
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found = internal_getut_r (data, &buffer);
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LOCK_FILE (file_fd, F_WRLCK);
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if (found < 0)
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{
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/* We append the next entry. */
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file_offset = __lseek64 (file_fd, 0, SEEK_END);
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if (file_offset % sizeof (struct utmp) != 0)
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{
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file_offset -= file_offset % sizeof (struct utmp);
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__ftruncate64 (file_fd, file_offset);
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if (__lseek64 (file_fd, 0, SEEK_END) < 0)
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{
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pbuf = NULL;
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goto unlock_return;
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}
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}
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}
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else
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{
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/* We replace the just read entry. */
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file_offset -= sizeof (struct utmp);
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__lseek64 (file_fd, file_offset, SEEK_SET);
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}
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/* Write the new data. */
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if (__write (file_fd, data, sizeof (struct utmp)) != sizeof (struct utmp))
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{
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/* If we appended a new record this is only partially written.
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Remove it. */
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if (found < 0)
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(void) __ftruncate64 (file_fd, file_offset);
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pbuf = NULL;
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}
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else
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{
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file_offset += sizeof (struct utmp);
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pbuf = (struct utmp *) data;
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}
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unlock_return:
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UNLOCK_FILE (file_fd);
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return pbuf;
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}
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static void
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endutent_file (void)
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{
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assert (file_fd >= 0);
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__close (file_fd);
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file_fd = -1;
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}
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static int
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updwtmp_file (const char *file, const struct utmp *utmp)
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{
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int result = -1;
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off64_t offset;
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int fd;
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/* Open WTMP file. */
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fd = __open (file, O_WRONLY);
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if (fd < 0)
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return -1;
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LOCK_FILE (fd, F_WRLCK);
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/* Remember original size of log file. */
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offset = __lseek64 (fd, 0, SEEK_END);
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if (offset % sizeof (struct utmp) != 0)
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{
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offset -= offset % sizeof (struct utmp);
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__ftruncate64 (fd, offset);
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if (__lseek64 (fd, 0, SEEK_END) < 0)
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goto unlock_return;
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}
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/* Write the entry. If we can't write all the bytes, reset the file
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size back to the original size. That way, no partial entries
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will remain. */
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if (__write (fd, utmp, sizeof (struct utmp)) != sizeof (struct utmp))
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{
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__ftruncate64 (fd, offset);
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goto unlock_return;
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}
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result = 0;
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unlock_return:
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UNLOCK_FILE (fd);
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/* Close WTMP file. */
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__close (fd);
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return result;
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}
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