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-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;
+}
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