path: root/src/utmp.c

/*  utmp.c -- Eterm utmp support

 * This program is distributed under the GNU Public License (GPL) as
 * outlined in the COPYING file.
 *
 * Copyright (C) 1997-1999, Michael Jennings and Tuomo Venalainen
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * 
 */

static const char cvs_ident[] = "$Id$";

#include "config.h"
#include "feature.h"

#ifdef UTMP_SUPPORT

# include <stdio.h>
# include <string.h>
/* For some systems (HP-UX in particular), sys/types.h must be included
   before utmp*.h -- mej */
# include <sys/types.h>
# include <sys/stat.h>
/* Unsupported/broken utmpx.h on HP-UX, AIX, and glibc 2.1 */
# if defined(_HPUX_SOURCE) || defined(_AIX) || ((__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1))
#   undef HAVE_UTMPX_H
# endif
# ifdef HAVE_UTMPX_H
#  include <utmpx.h>
#  define USE_SYSV_UTMP
# else
#  include <utmp.h>
#  ifdef HAVE_SETUTENT
#   define USE_SYSV_UTMP
#  endif
# endif
# ifdef TIME_WITH_SYS_TIME
#  include <sys/time.h>
#  include <time.h>
# else
#  ifdef HAVE_SYS_TIME_H
#   include <sys/time.h>
#  else
#   include <time.h>
#  endif
# endif
# ifdef HAVE_UNISTD_H
#  include <unistd.h>
# endif
# include <pwd.h>
# include <errno.h>
# ifdef HAVE_FCNTL_H
#  include <fcntl.h>
# endif
# ifdef HAVE_LASTLOG_H
#  include <lastlog.h>
# endif
# if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__)
#  include <ttyent.h>
# endif

# include "eterm_utmp.h"
# include "debug.h"
# include "../libmej/debug.h"
# include "command.h"
# include "screen.h"

/* screen.h includes config.h again, so re-fix these.  Pointed out by Sung-Hyun Nam <namsh@lgic.co.kr> */
# if defined(_HPUX_SOURCE) || defined(_AIX) || ((__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1))
#   undef HAVE_UTMPX_H
# endif

/* don't go off end of ut_id & remember if an entry has been made */
# ifndef HAVE_UTEMPTER
#  if defined(USE_SYSV_UTMP) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__bsdi__)
static char ut_id[5];		/* remember if entry to utmp made */
#  else
static int utmp_pos;		/* BSD position of utmp-stamp */
#  endif
# endif

# ifdef USE_SYSV_UTMP

#  ifdef HAVE_UTMPX_H
#   undef WTMP_FILENAME
#   define WTMP_FILENAME WTMPX_FILE
#   define update_wtmp updwtmpx
#  else				/* HAVE_UTMPX_H */

#   ifndef HAVE_UTEMPTER
static void
update_wtmp(char *fname, struct utmp *putmp)
{

  int fd, retry = 10;		/* 10 attempts at locking */
  struct flock lck;		/* fcntl locking scheme */

  if ((fd = open(fname, O_WRONLY | O_APPEND, 0)) < 0) {
    D_UTMP(("Warning:  Unable to open \"%s\" for writing -- %s\n", fname, strerror(errno)));
    return;
  }
  lck.l_whence = SEEK_END;	/* start lock at current eof */
  lck.l_len = 0;		/* end at ``largest possible eof'' */
  lck.l_start = 0;
  lck.l_type = F_WRLCK;		/* we want a write lock */

  /* attempt lock with F_SETLK - F_SETLKW would cause a deadlock! */
  while (retry--) {
    if ((fcntl(fd, F_SETLK, &lck) < 0) && errno != EACCESS) {
      D_UTMP(("Warning:  Unable to establish file lock on \"%s\" -- %s\n", fname, strerror(errno)));
      close(fd);
      return;			/* failed for unknown reason: give up */
    } else if (errno == EACCESS) {
      D_UTMP(("Warning:  Unable to establish file lock on \"%s\" -- %s\n", fname, strerror(errno)));
    }
  }

  write(fd, putmp, sizeof(struct utmp));

  /* unlocking the file */
  lck.l_type = F_UNLCK;
  fcntl(fd, F_SETLK, &lck);

  close(fd);
}
#   endif /* ifndef HAVE_UTEMPTER */
#  endif /* HAVE_UTMPX_H */

#  ifndef HAVE_UTEMPTER
void
add_utmp_entry(const char *pty, const char *hostname, int fd)
{
  struct passwd *pwent = getpwuid(my_ruid);

#   ifdef HAVE_UTMPX_H
  struct utmpx utmp;
  struct utmp utmp2;
  MEMSET(&utmp, 0, sizeof(struct utmpx));

#   else
  struct utmp utmp;
  MEMSET(&utmp, 0, sizeof(struct utmp));

#   endif

#   ifdef WITH_DMALLOC
  return;
#   endif

  if (!strncmp(pty, "/dev/", 5))
    pty += 5;			/* skip /dev/ prefix */
  if (!strncmp(pty, "pty", 3) || !strncmp(pty, "tty", 3))
    strncpy(ut_id, (pty + 3), sizeof(ut_id));	/* bsd naming */
  else {
    int n;

    if (sscanf(pty, "pts/%d", &n) == 1)
      sprintf(ut_id, "vt%02x", n);	/* sysv naming */
    else {
      print_error("can't parse tty name \"%s\"", pty);
      ut_id[0] = '\0';		/* entry not made */
      return;
    }
  }
  strncpy(utmp.ut_id, ut_id, sizeof(utmp.ut_id));
  utmp.ut_type = DEAD_PROCESS;

  privileges(INVOKE);
#   ifdef HAVE_UTMPX_H
  getutmp(&utmp, &utmp2);
  getutid(&utmp2);		/* position to entry in utmp file */
#   else
  getutid(&utmp);		/* position to entry in utmp file */
#   endif

  /* set up the new entry */
  strncpy(utmp.ut_id, ut_id, sizeof(utmp.ut_id));
  strncpy(utmp.ut_line, pty, sizeof(utmp.ut_line));
  strncpy(utmp.ut_name, pwent->pw_name, sizeof(utmp.ut_name));
  strncpy(utmp.ut_user, pwent->pw_name, sizeof(utmp.ut_user));
  strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
  utmp.ut_type = USER_PROCESS;
  utmp.ut_pid = getpid();
#   ifdef HAVE_UTMPX_H
  utmp.ut_session = getsid(0);
  utmp.ut_xtime = time(NULL);
  utmp.ut_tv.tv_usec = 0;
#   else
  utmp.ut_time = time(NULL);
#   endif

  /*
   * write a utmp entry to the utmp file
   */
  utmpname(UTMP_FILENAME);
#   ifdef HAVE_UTMPX_H
  getutmp(&utmp, &utmp2);
  pututline(&utmp2);
  pututxline(&utmp);
#   else
  pututline(&utmp);
#   endif
  update_wtmp(WTMP_FILENAME, &utmp);
  endutent();			/* close the file */
  privileges(REVERT);
  return;
  fd = 0;
}

void
remove_utmp_entry(void)
{
#   ifdef HAVE_UTMPX_H
  struct utmp utmp;
  struct utmpx utmpx;

  if (!ut_id[0])
    return;			/* entry not made */

  privileges(INVOKE);
  utmpname(UTMP_FILENAME);
  setutent();
  if (getutid(&utmp) == NULL)
    return;
  utmp.ut_type = DEAD_PROCESS;
  utmp.ut_time = time(NULL);
  pututline(&utmp);
  getutmpx(&utmp, &utmpx);
  update_wtmp(WTMP_FILENAME, &utmpx);
  endutent();
  privileges(REVERT);

#   else /* HAVE_UTMPX_H */
  struct utmp *putmp;
  pid_t pid = getpid();

  if (!ut_id[0])
    return;			/* entry not made */

  privileges(INVOKE);
  utmpname(UTMP_FILENAME);
  setutent();
  /*
   * The following code waw copied from the poeigl-1.20 login/init package.
   * Special thanks to poe for the code examples.
   */
  while ((putmp = getutent()) != NULL) {
    if (putmp->ut_pid == pid) {
      putmp->ut_type = DEAD_PROCESS;
      putmp->ut_pid = 0;
      putmp->ut_user[0] = '\0';
      putmp->ut_time = time(NULL);
      pututline(putmp);
      update_wtmp(WTMP_FILENAME, putmp);
      break;
    }
  }
  endutent();
  privileges(REVERT);
#   endif /* HAVE_UTMPX_H */
}
#  endif /* ifndef HAVE_UTEMPTER */

# else /* USE_SYSV_UTMP */
/* BSD utmp support */

#  if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__)

/* used to hold the line we are using */
static char ut_line[32];

static int
get_tslot(const char *ttyname)
{
  register struct ttyent *ttyp;
  register int slot;

  setttyent();
  for (slot = 1; (ttyp = getttyent()); ++slot)
    if (!strcmp(ttyp->ty_name, ttyname)) {
      endttyent();
      return (slot);
    }
  endttyent();
  return 0;
}

void
b_login(struct utmp *ut)
{
  /*
     ** replacement for freebsd's login(), which uses ttyslot()
     **
     ** like I shouldn't have just KNOWN that from the comment on get_tslot
     ** below...
     **            - brian
   */
  register int fd;
  int tty;

  tty = get_tslot(ut->ut_line);
  if (tty > 0 && (fd = open(_PATH_UTMP, O_WRONLY | O_CREAT, 0644)) >= 0) {
    (void) lseek(fd, (off_t) (tty * sizeof(struct utmp)), L_SET);
    (void) write(fd, ut, sizeof(struct utmp));

    (void) close(fd);
  }
  if ((fd = open(_PATH_WTMP, O_WRONLY | O_APPEND, 0)) >= 0) {
    (void) write(fd, ut, sizeof(struct utmp));

    (void) close(fd);
  }
}

#  else /* __FreeBSD__ || NetBSD || BSDI */
static int utmp_pos = 0;	/* position of utmp-stamp */

/*----------------------------------------------------------------------*
 * get_tslot() - grabbed from xvt-1.0 - modified by David Perry
 *
 * find ttyname in /etc/ttytab and return a slot number that can be used to
 * access the utmp file.  Can't use ttyslot() because the tty name is not
 * that of fd 0.
 *----------------------------------------------------------------------*/
static int
get_tslot(const char *ttyname)
{
  char buf[256], name[256];
  FILE *fd;

  if ((fd = fopen(UTMP_FILENAME, "r")) != NULL) {
    int i;

    for (i = 1; fgets(buf, sizeof(buf), fd) != NULL; i++) {
      if (*buf == '#' || sscanf(buf, "%s", name) != 1)
	continue;
      if (!strcmp(ttyname, name)) {
	fclose(fd);
	return i;
      }
    }
    fclose(fd);
  }
  return -1;
}

/*
 * write utmp entry to UTMP_FILENAME
 */
static int
write_utmp(struct utmp *putmp)
{
  int rval = 0;
  FILE *fd;

  fprintf(stderr, "Utmp file is %s\n", UTMP_FILENAME);
  privileges(INVOKE);
  if ((fd = fopen(UTMP_FILENAME, "r+")) != NULL) {
    utmp_pos = get_tslot(putmp->ut_line) * sizeof(struct utmp);

    if (utmp_pos >= 0) {
      fseek(fd, utmp_pos, 0);
      fwrite(putmp, sizeof(struct utmp), 1, fd);

      rval = 1;
    }
    fclose(fd);
  }
  privileges(REVERT);
  return rval;
}

#  endif /* __FreeBSD__ || NetBSD || BSDI */

void
add_utmp_entry(const char *pty, const char *hostname, int fd)
{
  struct passwd *pwent = getpwuid(my_ruid);
  struct utmp utmp;

  MEMSET(&utmp, 0, sizeof(struct utmp));

  if (!strncmp(pty, "/dev/", 5))
    pty += 5;			/* skip /dev/ prefix */
  if (!strncmp(pty, "pty", 3) || !strncmp(pty, "tty", 3))
    strncpy(ut_id, (pty + 3), sizeof(ut_id));	/* bsd naming */
  else {
    print_error("can't parse tty name \"%s\"", pty);
    ut_id[0] = '\0';		/* entry not made */
    return;
  }

#  if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__)
  strncpy(ut_line, pty, 31);

  strncpy(utmp.ut_line, pty, UT_LINESIZE);
  strncpy(utmp.ut_name, pwent->pw_name, UT_NAMESIZE);
  strncpy(utmp.ut_host, hostname, UT_HOSTSIZE);
  utmp.ut_time = time(NULL);

  b_login(&utmp);
#  else /* __FreeBSD__ || NetBSD || BSDI */
  strncpy(utmp.ut_line, ut_id, sizeof(utmp.ut_line));
  strncpy(utmp.ut_name, pwent->pw_name, sizeof(utmp.ut_name));
  strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
  utmp.ut_time = time(NULL);

  if (write_utmp(&utmp) < 0)
    ut_id[0] = '\0';		/* entry not made */
#  endif
  return;
  fd = 0;
}

/*
 * remove a utmp entry
 */
void
remove_utmp_entry(void)
{
#  if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__)
  logout(ut_line);
  logwtmp(ut_line, "", "");
#  else /* __FreeBSD__ */
  FILE *fd;

  privileges(INVOKE);
  if (!ut_id[0] && (fd = fopen(UTMP_FILENAME, "r+")) != NULL) {
    struct utmp utmp;
    MEMSET(&utmp, 0, sizeof(struct utmp));

    fseek(fd, utmp_pos, 0);
    fwrite(&utmp, sizeof(struct utmp), 1, fd);

    fclose(fd);
  }
  privileges(REVERT);
#  endif /* __FreeBSD__ || NetBSD || BSDI */
}

# endif /* USE_SYSV_UTMP */

#endif /* UTMP_SUPPORT */