/*

 * Copyright (c) 2000 Andre Lucas.  All rights reserved.

 * Portions copyright (c) 1998 Todd C. Miller

 * Portions copyright (c) 1996 Jason Downs

 * Portions copyright (c) 1996 Theo de Raadt

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/**

 ** loginrec.c:  platform-independent login recording and lastlog retrieval

 **/

/* For now lastlog code has been removed as it wasn't being used by Dropbear. */

/*

  The new login code explained

  ============================

  This code attempts to provide a common interface to login recording

  (utmp and friends) and last login time retrieval.

  Its primary means of achieving this is to use 'struct logininfo', a

  union of all the useful fields in the various different types of

  system login record structures one finds on UNIX variants.

  We depend on autoconf to define which recording methods are to be

  used, and which fields are contained in the relevant data structures

  on the local system. Many C preprocessor symbols affect which code

  gets compiled here.

  The code is designed to make it easy to modify a particular

  recording method, without affecting other methods nor requiring so

  many nested conditional compilation blocks as were commonplace in

  the old code.

  For login recording, we try to use the local system's libraries as

  these are clearly most likely to work correctly. For utmp systems

  this usually means login() and logout() or setutent() etc., probably

  in libutil, along with logwtmp() etc. On these systems, we fall back

  to writing the files directly if we have to, though this method

  requires very thorough testing so we do not corrupt local auditing

  information. These files and their access methods are very system

  specific indeed.

  For utmpx systems, the corresponding library functions are

  setutxent() etc. To the author's knowledge, all utmpx systems have

  these library functions and so no direct write is attempted. If such

  a system exists and needs support, direct analogues of the [uw]tmp

  code should suffice.

  Retrieving the time of last login ('lastlog') is in some ways even

  more problemmatic than login recording. Some systems provide a

  simple table of all users which we seek based on uid and retrieve a

  relatively standard structure. Others record the same information in

  a directory with a separate file, and others don't record the

  information separately at all. For systems in the latter category,

  we look backwards in the wtmp or wtmpx file for the last login entry

  for our user. Naturally this is slower and on busy systems could

  incur a significant performance penalty.

  Calling the new code

  --------------------

  In OpenSSH all login recording and retrieval is performed in

  login.c. Here you'll find working examples. Also, in the logintest.c

  program there are more examples.

  Internal handler calling method

  -------------------------------

  When a call is made to login_login() or login_logout(), both

  routines set a struct logininfo flag defining which action (log in,

  or log out) is to be taken. They both then call login_write(), which

  calls whichever of the many structure-specific handlers autoconf

  selects for the local system.

  The handlers themselves handle system data structure specifics. Both

  struct utmp and struct utmpx have utility functions (see

  construct_utmp*()) to try to make it simpler to add extra systems

  that introduce new features to either structure.

  While it may seem terribly wasteful to replicate so much similar

  code for each method, experience has shown that maintaining code to

  write both struct utmp and utmpx in one function, whilst maintaining

  support for all systems whether they have library support or not, is

  a difficult and time-consuming task.

  Lastlog support proceeds similarly. Functions login_get_lastlog()

  (and its OpenSSH-tuned friend login_get_lastlog_time()) call

  getlast_entry(), which tries one of three methods to find the last

  login time. It uses local system lastlog support if it can,

  otherwise it tries wtmp or wtmpx before giving up and returning 0,

  meaning "tilt".

  Maintenance

  -----------

  In many cases it's possible to tweak autoconf to select the correct

  methods for a particular platform, either by improving the detection

  code (best), or by presetting DISABLE_<method> or CONF_<method>_FILE

  symbols for the platform.

  Use logintest to check which symbols are defined before modifying

  configure.ac and loginrec.c. (You have to build logintest yourself

  with 'make logintest' as it's not built by default.)

  Otherwise, patches to the specific method(s) are very helpful!

*/

/**

 ** TODO:

 **   homegrown ttyslot()

 **   test, test, test

 **

 ** Platform status:

 ** ----------------

 **

 ** Known good:

 **   Linux (Redhat 6.2, Debian)

 **   Solaris

 **   HP-UX 10.20 (gcc only)

 **   IRIX

 **   NeXT - M68k/HPPA/Sparc (4.2/3.3)

 **

 ** Testing required: Please send reports!

 **   NetBSD

 **   HP-UX 11

 **   AIX

 **

 ** Platforms with known problems:

 **   Some variants of Slackware Linux

 **

 **/

#include "includes.h"

#include "loginrec.h"

#include "dbutil.h"

#include "atomicio.h"

/**

 ** prototypes for helper functions in this file

 **/

#if HAVE_UTMP_H

void set_utmp_time(struct logininfo *li, struct utmp *ut);

void construct_utmp(struct logininfo *li, struct utmp *ut);

#endif

#ifdef HAVE_UTMPX_H

void set_utmpx_time(struct logininfo *li, struct utmpx *ut);

void construct_utmpx(struct logininfo *li, struct utmpx *ut);

#endif

int utmp_write_entry(struct logininfo *li);

int utmpx_write_entry(struct logininfo *li);

int wtmp_write_entry(struct logininfo *li);

int wtmpx_write_entry(struct logininfo *li);

int lastlog_write_entry(struct logininfo *li);

int syslogin_write_entry(struct logininfo *li);

int wtmp_get_entry(struct logininfo *li);

int wtmpx_get_entry(struct logininfo *li);

/* pick the shortest string */

#define MIN_SIZEOF(s1,s2) ( sizeof(s1) < sizeof(s2) ? sizeof(s1) : sizeof(s2) )

/**

 ** platform-independent login functions

 **/

/* login_login(struct logininfo *)     -Record a login

 *

 * Call with a pointer to a struct logininfo initialised with

 * login_init_entry() or login_alloc_entry()

 */

void

login_login (struct logininfo *li)

{

  li->type = LTYPE_LOGIN;

  login_write(li);

}

/* login_logout(struct logininfo *)     - Record a logout

 *

 * Call as with login_login()

 */

void

login_logout(struct logininfo *li)

{

  li->type = LTYPE_LOGOUT;

  login_write(li);

}

/* login_alloc_entry(int, char*, char*, char*)    - Allocate and initialise

 *                                                  a logininfo structure

 *

 * This function creates a new struct logininfo, a data structure

 * meant to carry the information required to portably record login info.

 *

 * Returns a pointer to a newly created struct logininfo. If memory

 * allocation fails, the program halts.

 */

struct

logininfo *login_alloc_entry(int pid, const char *username,

           const char *hostname, const char *line)

{

  struct logininfo *newli;

  newli = (struct logininfo *) m_malloc (sizeof(*newli));

  (void)login_init_entry(newli, pid, username, hostname, line);

  return newli;

}

/* login_free_entry(struct logininfo *)    - free struct memory */

void

login_free_entry(struct logininfo *li)

{

  m_free(li);

}

/* login_init_entry(struct logininfo *, int, char*, char*, char*)

 *                                        - initialise a struct logininfo

 *

 * Populates a new struct logininfo, a data structure meant to carry

 * the information required to portably record login info.

 *

 * Returns: 1

 */

int

login_init_entry(struct logininfo *li, int pid, const char *username,

     const char *hostname, const char *line)

{

  struct passwd *pw;

  memset(li, 0, sizeof(*li));

  li->pid = pid;

  /* set the line information */

  if (line)

    line_fullname(li->line, line, sizeof(li->line));

  if (username) {

    strlcpy(li->username, username, sizeof(li->username));

    pw = getpwnam(li->username);

    if (pw == NULL)

      dropbear_exit("login_init_entry: Cannot find user \"%s\"",

          li->username);

    li->uid = pw->pw_uid;

  }

  if (hostname)

    strlcpy(li->hostname, hostname, sizeof(li->hostname));

  return 1;

}

/* login_set_current_time(struct logininfo *)    - set the current time

 *

 * Set the current time in a logininfo structure. This function is

 * meant to eliminate the need to deal with system dependencies for

 * time handling.

 */

void

login_set_current_time(struct logininfo *li)

{

  struct timeval tv;

  gettimeofday(&tv, NULL);

  li->tv_sec = tv.tv_sec;

  li->tv_usec = tv.tv_usec;

}

/**

 ** login_write: Call low-level recording functions based on autoconf

 ** results

 **/

void

login_write (struct logininfo *li)

{

  /* set the timestamp */

  login_set_current_time(li);

#ifdef USE_LOGIN

  syslogin_write_entry(li);

#endif

#ifdef USE_LASTLOG

  if (li->type == LTYPE_LOGIN) {

    lastlog_write_entry(li);

  }

#endif

#ifdef USE_UTMP

  utmp_write_entry(li);

#endif

#ifdef USE_WTMP

  wtmp_write_entry(li);

#endif

#ifdef USE_UTMPX

  utmpx_write_entry(li);

#endif

#ifdef USE_WTMPX

  wtmpx_write_entry(li);

#endif

}

#ifdef LOGIN_NEEDS_UTMPX

int

login_utmp_only(struct logininfo *li)

{

  li->type = LTYPE_LOGIN; 

  login_set_current_time(li);

# ifdef USE_UTMP

  utmp_write_entry(li);

# endif

# ifdef USE_WTMP

  wtmp_write_entry(li);

# endif

# ifdef USE_UTMPX

  utmpx_write_entry(li);

# endif

# ifdef USE_WTMPX

  wtmpx_write_entry(li);

# endif

  return 0;

}

#endif

/*

 * 'line' string utility functions

 *

 * These functions process the 'line' string into one of three forms:

 *

 * 1. The full filename (including '/dev')

 * 2. The stripped name (excluding '/dev')

 * 3. The abbreviated name (e.g. /dev/ttyp00 -> yp00

 *                               /dev/pts/1  -> ts/1 )

 *

 * Form 3 is used on some systems to identify a .tmp.? entry when

 * attempting to remove it. Typically both addition and removal is

 * performed by one application - say, sshd - so as long as the choice

 * uniquely identifies a terminal it's ok.

 */

/* line_fullname(): add the leading '/dev/' if it doesn't exist make

 * sure dst has enough space, if not just copy src (ugh) */

char *

line_fullname(char *dst, const char *src, size_t dstsize)

{

  memset(dst, '\0', dstsize);

  if ((strncmp(src, "/dev/", 5) == 0) || (dstsize < (strlen(src) + 5))) {

    strlcpy(dst, src, dstsize);

  } else {

    strlcpy(dst, "/dev/", dstsize);

    strlcat(dst, src, dstsize);

  }

  return dst;

}

/* line_stripname(): strip the leading '/dev' if it exists, return dst */

char *

line_stripname(char *dst, const char *src, size_t dstsize)

{

  memset(dst, '\0', dstsize);

  if (strncmp(src, "/dev/", 5) == 0)

    strlcpy(dst, src + 5, dstsize);

  else

    strlcpy(dst, src, dstsize);

  return dst;

}

/* line_abbrevname(): Return the abbreviated (usually four-character)

 * form of the line (Just use the last <dstsize> characters of the

 * full name.)

 *

 * NOTE: use strncpy because we do NOT necessarily want zero

 * termination */

char *

line_abbrevname(char *dst, const char *src, size_t dstsize)

{

  size_t len;

  memset(dst, '\0', dstsize);

  /* Always skip prefix if present */

  if (strncmp(src, "/dev/", 5) == 0)

    src += 5;

#ifdef WITH_ABBREV_NO_TTY

  if (strncmp(src, "tty", 3) == 0)

    src += 3;

#endif

  len = strlen(src);

  if (len > 0) {

    if (((int)len - dstsize) > 0)

      src +=  ((int)len - dstsize);

    /* note: _don't_ change this to strlcpy */

    strncpy(dst, src, (size_t)dstsize);

  }

  return dst;

}

/**

 ** utmp utility functions

 **

 ** These functions manipulate struct utmp, taking system differences

 ** into account.

 **/

#if defined(USE_UTMP) || defined (USE_WTMP) || defined (USE_LOGIN)

/* build the utmp structure */

void

set_utmp_time(struct logininfo *li, struct utmp *ut)

{

  /* struct utmp in glibc isn't y2038 safe yet */

# ifdef HAVE_STRUCT_UTMP_UT_TV

  ut->ut_tv.tv_sec = li->tv_sec;

  ut->ut_tv.tv_usec = li->tv_usec;

# else

#  ifdef HAVE_STRUCT_UTMP_UT_TIME

  ut->ut_time = li->tv_sec;

#  endif

# endif

}

void

construct_utmp(struct logininfo *li,

        struct utmp *ut)

{

# ifdef HAVE_ADDR_V6_IN_UTMP

  struct sockaddr_in6 *sa6;

#  endif

  memset(ut, '\0', sizeof(*ut));

  /* First fill out fields used for both logins and logouts */

# ifdef HAVE_STRUCT_UTMP_UT_ID

  line_abbrevname(ut->ut_id, li->line, sizeof(ut->ut_id));

# endif

# ifdef HAVE_STRUCT_UTMP_UT_TYPE

  /* This is done here to keep utmp constants out of struct logininfo */

  switch (li->type) {

  case LTYPE_LOGIN:

    ut->ut_type = USER_PROCESS;

#ifdef _UNICOS

    cray_set_tmpdir(ut);

#endif

    break;

  case LTYPE_LOGOUT:

    ut->ut_type = DEAD_PROCESS;

#ifdef _UNICOS

    cray_retain_utmp(ut, li->pid);

#endif

    break;

  }

# endif

  set_utmp_time(li, ut);

  line_stripname(ut->ut_line, li->line, sizeof(ut->ut_line));

# ifdef HAVE_STRUCT_UTMP_UT_PID

  ut->ut_pid = li->pid;

# endif

  /* If we're logging out, leave all other fields blank */

  if (li->type == LTYPE_LOGOUT)

    return;

  /*

   * These fields are only used when logging in, and are blank

   * for logouts.

   */

  /* Use strncpy because we don't necessarily want null termination */

  strncpy(ut->ut_name, li->username, MIN_SIZEOF(ut->ut_name, li->username));

# ifdef HAVE_STRUCT_UTMP_UT_HOST

  strncpy(ut->ut_host, li->hostname, MIN_SIZEOF(ut->ut_host, li->hostname));

# endif

# ifdef HAVE_STRUCT_UTMP_UT_ADDR

  /* this is just a 32-bit IP address */

  if (li->hostaddr.sa.sa_family == AF_INET)

    ut->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;

# endif

# ifdef HAVE_ADDR_V6_IN_UTMP

  /* this is just a 128-bit IPv6 address */

  if (li->hostaddr.sa.sa_family == AF_INET6) {

    sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa);

    memcpy(ut->ut_addr_v6, sa6->sin6_addr.s6_addr, 16);

    if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) {

      ut->ut_addr_v6[0] = ut->ut_addr_v6[3];

      ut->ut_addr_v6[1] = 0;

      ut->ut_addr_v6[2] = 0;

      ut->ut_addr_v6[3] = 0;

    }

  }

# endif

}

#endif /* USE_UTMP || USE_WTMP || USE_LOGIN */

/**

 ** utmpx utility functions

 **

 ** These functions manipulate struct utmpx, accounting for system

 ** variations.

 **/

#if defined(USE_UTMPX) || defined (USE_WTMPX)

/* build the utmpx structure */

void

set_utmpx_time(struct logininfo *li, struct utmpx *utx)

{

# ifdef HAVE_STRUCT_UTMPX_UT_TV

  utx->ut_tv.tv_sec = li->tv_sec;

  utx->ut_tv.tv_usec = li->tv_usec;

# else /* HAVE_STRUCT_UTMPX_UT_TV */

#  ifdef HAVE_STRUCT_UTMPX_UT_TIME

  utx->ut_time = li->tv_sec;

#  endif /* HAVE_STRUCT_UTMPX_UT_TIME */

# endif /* HAVE_STRUCT_UTMPX_UT_TV */

}

void

construct_utmpx(struct logininfo *li, struct utmpx *utx)

{

# ifdef HAVE_ADDR_V6_IN_UTMP

  struct sockaddr_in6 *sa6;

#  endif

  memset(utx, '\0', sizeof(*utx));

# ifdef HAVE_STRUCT_UTMPX_UT_ID

  line_abbrevname(utx->ut_id, li->line, sizeof(utx->ut_id));

# endif

  /* this is done here to keep utmp constants out of loginrec.h */

  switch (li->type) {

  case LTYPE_LOGIN:

    utx->ut_type = USER_PROCESS;

    break;

  case LTYPE_LOGOUT:

    utx->ut_type = DEAD_PROCESS;

    break;

  }

  line_stripname(utx->ut_line, li->line, sizeof(utx->ut_line));

  set_utmpx_time(li, utx);

  utx->ut_pid = li->pid;

  /* strncpy(): Don't necessarily want null termination */

  strncpy(utx->ut_name, li->username, MIN_SIZEOF(utx->ut_name, li->username));

  if (li->type == LTYPE_LOGOUT)

    return;

  /*

   * These fields are only used when logging in, and are blank

   * for logouts.

   */

# ifdef HAVE_STRUCT_UTMPX_UT_HOST

  strncpy(utx->ut_host, li->hostname, MIN_SIZEOF(utx->ut_host, li->hostname));

# endif

# ifdef HAVE_STRUCT_UTMPX_UT_ADDR

  /* this is just a 32-bit IP address */

  if (li->hostaddr.sa.sa_family == AF_INET)

    utx->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;

# endif

# ifdef HAVE_ADDR_V6_IN_UTMP

  /* this is just a 128-bit IPv6 address */

  if (li->hostaddr.sa.sa_family == AF_INET6) {

    sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa);

    memcpy(ut->ut_addr_v6, sa6->sin6_addr.s6_addr, 16);

    if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) {

      ut->ut_addr_v6[0] = ut->ut_addr_v6[3];

      ut->ut_addr_v6[1] = 0;

      ut->ut_addr_v6[2] = 0;

      ut->ut_addr_v6[3] = 0;

    }

  }

# endif

# ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN

  /* ut_syslen is the length of the utx_host string */

  utx->ut_syslen = MIN(strlen(li->hostname), sizeof(utx->ut_host));

# endif

}

#endif /* USE_UTMPX || USE_WTMPX */

/**

 ** Low-level utmp functions

 **/

/* FIXME: (ATL) utmp_write_direct needs testing */

#ifdef USE_UTMP

/* if we can, use pututline() etc. */

# if !defined(DISABLE_PUTUTLINE) && defined(HAVE_SETUTENT) && \

  defined(HAVE_PUTUTLINE)

#  define UTMP_USE_LIBRARY

# endif

/* write a utmp entry with the system's help (pututline() and pals) */

# ifdef UTMP_USE_LIBRARY

static int

utmp_write_library(struct logininfo *li, struct utmp *ut)

{

  setutent();

  pututline(ut);

#  ifdef HAVE_ENDUTENT

  endutent();

#  endif

  return 1;

}

# else /* UTMP_USE_LIBRARY */

/* write a utmp entry direct to the file */

/* This is a slightly modification of code in OpenBSD's login.c */

static int

utmp_write_direct(struct logininfo *li, struct utmp *ut)

{

  struct utmp old_ut;

  register int fd;

  int tty;

  /* FIXME: (ATL) ttyslot() needs local implementation */

#if defined(HAVE_GETTTYENT)

  register struct ttyent *ty;

  tty=0;

  setttyent();

  while ((struct ttyent *)0 != (ty = getttyent())) {

    tty++;

    if (!strncmp(ty->ty_name, ut->ut_line, sizeof(ut->ut_line)))

      break;

  }

  endttyent();

  if((struct ttyent *)0 == ty) {

    dropbear_log(LOG_WARNING, "utmp_write_entry: tty not found");

    return(1);

  }

#else /* FIXME */

  tty = ttyslot(); /* seems only to work for /dev/ttyp? style names */

#endif /* HAVE_GETTTYENT */

  if (tty > 0 && (fd = open(UTMP_FILE, O_RDWR|O_CREAT, 0644)) >= 0) {

    (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);

    /*

     * Prevent luser from zero'ing out ut_host.

     * If the new ut_line is empty but the old one is not

     * and ut_line and ut_name match, preserve the old ut_line.

     */

    if (atomicio(read, fd, &old_ut, sizeof(old_ut)) == sizeof(old_ut) &&

      (ut->ut_host[0] == '\0') && (old_ut.ut_host[0] != '\0') &&

      (strncmp(old_ut.ut_line, ut->ut_line, sizeof(ut->ut_line)) == 0) &&

      (strncmp(old_ut.ut_name, ut->ut_name, sizeof(ut->ut_name)) == 0)) {

      (void)memcpy(ut->ut_host, old_ut.ut_host, sizeof(ut->ut_host));

    }

    (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);

    if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut))

      dropbear_log(LOG_WARNING, "utmp_write_direct: error writing %s: %s",

          UTMP_FILE, strerror(errno));

    (void)close(fd);

    return 1;

  } else {

    return 0;

  }

}

# endif /* UTMP_USE_LIBRARY */

static int

utmp_perform_login(struct logininfo *li)

{

  struct utmp ut;

  construct_utmp(li, &ut);

# ifdef UTMP_USE_LIBRARY

  if (!utmp_write_library(li, &ut)) {

    dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_library() failed");

    return 0;

  }

# else

  if (!utmp_write_direct(li, &ut)) {

    dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_direct() failed");

    return 0;

  }

# endif

  return 1;

}

static int

utmp_perform_logout(struct logininfo *li)

{

  struct utmp ut;

  construct_utmp(li, &ut);

# ifdef UTMP_USE_LIBRARY

  if (!utmp_write_library(li, &ut)) {

    dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_library() failed");

    return 0;

  }

# else

  if (!utmp_write_direct(li, &ut)) {

    dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_direct() failed");

    return 0;

  }

# endif

  return 1;

}

int

utmp_write_entry(struct logininfo *li)

{

  switch(li->type) {

  case LTYPE_LOGIN:

    return utmp_perform_login(li);

  case LTYPE_LOGOUT:

    return utmp_perform_logout(li);

  default:

    dropbear_log(LOG_WARNING, "utmp_write_entry: invalid type field");

    return 0;

  }

}

#endif /* USE_UTMP */

/**

 ** Low-level utmpx functions

 **/

/* not much point if we don't want utmpx entries */

#ifdef USE_UTMPX

/* if we have the wherewithall, use pututxline etc. */

# if !defined(DISABLE_PUTUTXLINE) && defined(HAVE_SETUTXENT) && \

  defined(HAVE_PUTUTXLINE)

#  define UTMPX_USE_LIBRARY

# endif

/* write a utmpx entry with the system's help (pututxline() and pals) */

# ifdef UTMPX_USE_LIBRARY

static int

utmpx_write_library(struct logininfo *li, struct utmpx *utx)

{

  setutxent();

  pututxline(utx);

#  ifdef HAVE_ENDUTXENT

  endutxent();

#  endif

  return 1;

}

# else /* UTMPX_USE_LIBRARY */

/* write a utmp entry direct to the file */

static int

utmpx_write_direct(struct logininfo *li, struct utmpx *utx)

{

  dropbear_log(LOG_WARNING, "utmpx_write_direct: not implemented!");

  return 0;

}

# endif /* UTMPX_USE_LIBRARY */

static int

utmpx_perform_login(struct logininfo *li)

{

  struct utmpx utx;

  construct_utmpx(li, &utx);

# ifdef UTMPX_USE_LIBRARY

  if (!utmpx_write_library(li, &utx)) {

    dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_library() failed");

    return 0;

  }

# else

  if (!utmpx_write_direct(li, &utx)) {

    dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_direct() failed");

    return 0;

  }

# endif

  return 1;

}

static int

utmpx_perform_logout(struct logininfo *li)

{

  struct utmpx utx;

  construct_utmpx(li, &utx);

# ifdef HAVE_STRUCT_UTMPX_UT_ID

  line_abbrevname(utx.ut_id, li->line, sizeof(utx.ut_id));

# endif

# ifdef HAVE_STRUCT_UTMPX_UT_TYPE

  utx.ut_type = DEAD_PROCESS;

# endif

# ifdef UTMPX_USE_LIBRARY

  utmpx_write_library(li, &utx);

# else

  utmpx_write_direct(li, &utx);

# endif

  return 1;

}

int

utmpx_write_entry(struct logininfo *li)

{

  switch(li->type) {

  case LTYPE_LOGIN:

    return utmpx_perform_login(li);

  case LTYPE_LOGOUT:

    return utmpx_perform_logout(li);

  default:

    dropbear_log(LOG_WARNING, "utmpx_write_entry: invalid type field");

    return 0;

  }

}

#endif /* USE_UTMPX */

/**

 ** Low-level wtmp functions

 **/

#ifdef USE_WTMP

/* write a wtmp entry direct to the end of the file */

/* This is a slight modification of code in OpenBSD's logwtmp.c */

static int

wtmp_write(struct logininfo *li, struct utmp *ut)

{

  struct stat buf;

  int fd, ret = 1;

  if ((fd = open(WTMP_FILE, O_WRONLY|O_APPEND, 0)) < 0) {

    dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s",

        WTMP_FILE, strerror(errno));

    return 0;

  }

  if (fstat(fd, &buf) == 0)

    if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut)) {

      ftruncate(fd, buf.st_size);

      dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s",

          WTMP_FILE, strerror(errno));

      ret = 0;

    }

  (void)close(fd);

  return ret;

}

static int

wtmp_perform_login(struct logininfo *li)

{

  struct utmp ut;

  construct_utmp(li, &ut);

  return wtmp_write(li, &ut);

}

static int

wtmp_perform_logout(struct logininfo *li)

{

  struct utmp ut;

  construct_utmp(li, &ut);

  return wtmp_write(li, &ut);

}

int

wtmp_write_entry(struct logininfo *li)

{

  switch(li->type) {

  case LTYPE_LOGIN:

    return wtmp_perform_login(li);

  case LTYPE_LOGOUT:

    return wtmp_perform_logout(li);

  default:

    dropbear_log(LOG_WARNING, "wtmp_write_entry: invalid type field");

    return 0;

  }

}

/* Notes on fetching login data from wtmp/wtmpx

 *

 * Logouts are usually recorded with (amongst other things) a blank

 * username on a given tty line.  However, some systems (HP-UX is one)

 * leave all fields set, but change the ut_type field to DEAD_PROCESS.

 *

 * Since we're only looking for logins here, we know that the username

 * must be set correctly. On systems that leave it in, we check for

 * ut_type==USER_PROCESS (indicating a login.)

 *

 * Portability: Some systems may set something other than USER_PROCESS

 * to indicate a login process. I don't know of any as I write. Also,

 * it's possible that some systems may both leave the username in

 * place and not have ut_type.

 */

/* return true if this wtmp entry indicates a login */

static int

wtmp_islogin(struct logininfo *li, struct utmp *ut)

{

  if (strncmp(li->username, ut->ut_name,

    MIN_SIZEOF(li->username, ut->ut_name)) == 0) {

# ifdef HAVE_STRUCT_UTMP_UT_TYPE

    if (ut->ut_type & USER_PROCESS)

      return 1;

# else

    return 1;

# endif

  }

  return 0;

}

int

wtmp_get_entry(struct logininfo *li)

{

  struct stat st;

  struct utmp ut;

  int fd, found=0;

  /* Clear the time entries in our logininfo */

  li->tv_sec = li->tv_usec = 0;

  if ((fd = open(WTMP_FILE, O_RDONLY)) < 0) {

    dropbear_log(LOG_WARNING, "wtmp_get_entry: problem opening %s: %s",

        WTMP_FILE, strerror(errno));

    return 0;

  }

  if (fstat(fd, &st) != 0) {

    dropbear_log(LOG_WARNING, "wtmp_get_entry: couldn't stat %s: %s",

        WTMP_FILE, strerror(errno));

    close(fd);

    return 0;

  }

  /* Seek to the start of the last struct utmp */

  if (lseek(fd, -(off_t)sizeof(struct utmp), SEEK_END) == -1) {

    /* Looks like we've got a fresh wtmp file */

    close(fd);

    return 0;

  }

  while (!found) {

    if (atomicio(read, fd, &ut, sizeof(ut)) != sizeof(ut)) {

      dropbear_log(LOG_WARNING, "wtmp_get_entry: read of %s failed: %s",

          WTMP_FILE, strerror(errno));

      close (fd);

      return 0;

    }

    if ( wtmp_islogin(li, &ut) ) {

      found = 1;

      /* We've already checked for a time in struct

       * utmp, in login_getlast(). */

# ifdef HAVE_STRUCT_UTMP_UT_TIME

      li->tv_sec = ut.ut_time;

# else

#  if HAVE_STRUCT_UTMP_UT_TV

      li->tv_sec = ut.ut_tv.tv_sec;

#  endif

# endif

      line_fullname(li->line, ut.ut_line,

              MIN_SIZEOF(li->line, ut.ut_line));

# ifdef HAVE_STRUCT_UTMP_UT_HOST

      strlcpy(li->hostname, ut.ut_host,

        MIN_SIZEOF(li->hostname, ut.ut_host));

# endif

      continue;

    }

    /* Seek back 2 x struct utmp */

    if (lseek(fd, -(off_t)(2 * sizeof(struct utmp)), SEEK_CUR) == -1) {

      /* We've found the start of the file, so quit */

      close (fd);

      return 0;

    }

  }

  /* We found an entry. Tidy up and return */

  close(fd);

  return 1;

}

# endif /* USE_WTMP */

/**

 ** Low-level wtmpx functions

 **/

#ifdef USE_WTMPX

/* write a wtmpx entry direct to the end of the file */

/* This is a slight modification of code in OpenBSD's logwtmp.c */

static int

wtmpx_write(struct logininfo *li, struct utmpx *utx)

{

  struct stat buf;

  int fd, ret = 1;

  if ((fd = open(WTMPX_FILE, O_WRONLY|O_APPEND, 0)) < 0) {

    dropbear_log(LOG_WARNING, "wtmpx_write: problem opening %s: %s",

        WTMPX_FILE, strerror(errno));

    return 0;

  }

  if (fstat(fd, &buf) == 0)

    if (atomicio(vwrite, fd, utx, sizeof(*utx)) != sizeof(*utx)) {

      ftruncate(fd, buf.st_size);

      dropbear_log(LOG_WARNING, "wtmpx_write: problem writing %s: %s",

          WTMPX_FILE, strerror(errno));

      ret = 0;

    }

  (void)close(fd);

  return ret;

}

static int

wtmpx_perform_login(struct logininfo *li)

{

  struct utmpx utx;

  construct_utmpx(li, &utx);

  return wtmpx_write(li, &utx);

}

static int

wtmpx_perform_logout(struct logininfo *li)

{

  struct utmpx utx;

  construct_utmpx(li, &utx);

  return wtmpx_write(li, &utx);

}

int

wtmpx_write_entry(struct logininfo *li)

{

  switch(li->type) {

  case LTYPE_LOGIN:

    return wtmpx_perform_login(li);