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;
+}