source/smbd/utmp.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2.0
   4    utmp routines
   5    Copyright (C) T.D.Lee@durham.ac.uk 1999
   6    Heavily modified by Andrew Bartlett and Tridge, April 2001
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 #ifdef WITH_UTMP
  26
  27 /****************************************************************************
  28 Reflect connection status in utmp/wtmp files.
  29         T.D.Lee@durham.ac.uk  September 1999
  30
  31         With grateful thanks since then to many who have helped port it to
  32         different operating systems.  The variety of OS quirks thereby
  33         uncovered is amazing...
  34
  35 Hints for porting:
  36         o  Always attempt to use programmatic interface (pututline() etc.)
  37            Indeed, at present only programmatic use is supported.
  38         o  The only currently supported programmatic interface to "wtmp{,x}"
  39            is through "updwtmp*()" routines.
  40         o  The "x" (utmpx/wtmpx; HAVE_UTMPX_H) seems preferable.
  41         o  The HAVE_* items should identify supported features.
  42         o  If at all possible, avoid "if defined(MY-OS)" constructions.
  43
  44 OS observations and status:
  45         Almost every OS seems to have its own quirks.
  46
  47         Solaris 2.x:
  48                 Tested on 2.6 and 2.7; should be OK on other flavours.
  49         AIX:
  50                 Apparently has utmpx.h but doesn't implement.
  51         OSF:
  52                 Has utmpx.h, but (e.g.) no "getutmpx()".  (Is this like AIX ?)
  53         Redhat 6:
  54                 utmpx.h seems not to set default filenames.  non-x better.
  55         IRIX 6.5:
  56                 Not tested.  Appears to have "x".
  57         HP-UX 9.x:
  58                 Not tested.  Appears to lack "x".
  59         HP-UX 10.x:
  60                 Not tested.
  61                 "updwtmp*()" routines seem absent, so no current wtmp* support.
  62                 Has "ut_addr": probably trivial to implement (although remember
  63                 that IPv6 is coming...).
  64
  65         FreeBSD:
  66                 No "putut*()" type of interface.
  67                 No "ut_type" and associated defines.
  68                 Write files directly.  Alternatively use its login(3)/logout(3).
  69         SunOS 4:
  70                 Not tested.  Resembles FreeBSD, but no login()/logout().
  71
  72 lastlog:
  73         Should "lastlog" files, if any, be updated?
  74         BSD systems (SunOS 4, FreeBSD):
  75                 o  Prominent mention on man pages.
  76         System-V (e.g. Solaris 2):
  77                 o  No mention on man pages, even under "man -k".
  78                 o  Has a "/var/adm/lastlog" file, but pututxline() etc. seem
  79                    not to touch it.
  80                 o  Despite downplaying (above), nevertheless has <lastlog.h>.
  81         So perhaps UN*X "lastlog" facility is intended for tty/terminal only?
  82
  83 Notes:
  84         Each connection requires a small number (starting at 0, working up)
  85         to represent the line (unum).  This must be unique within and across
  86         all smbd processes.
  87
  88         The 4 byte 'ut_id' component is vital to distinguish connections,
  89         of which there could be several hundered or even thousand.
  90         Entries seem to be printable characters, with optional NULL pads.
  91
  92         We need to be distinct from other entries in utmp/wtmp.
  93
  94         Observed things: therefore avoid them.  Add to this list please.
  95         From Solaris 2.x (because that's what I have):
  96                 'sN'    : run-levels; N: [0-9]
  97                 'co'    : console
  98                 'CC'    : arbitrary things;  C: [a-z]
  99                 'rXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
 100                 'tXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
 101                 '/NNN'  : Solaris CDE
 102                 'ftpZ'  : ftp (Z is the number 255, aka 0377, aka 0xff)
 103         Mostly a record uses the same 'ut_id' in both "utmp" and "wtmp",
 104         but differences have been seen.
 105
 106         Arbitrarily I have chosen to use a distinctive 'SM' for the
 107         first two bytes.
 108
 109         The remaining two encode the "unum" (see above).
 110
 111         For "utmp consolidate" the suggestion was made to encode the pid into
 112         those remaining two bytes (16 bits).  But recent UNIX (e.g Solaris 8)
 113         is migrating to pids > 16 bits, so we ought not to do this.
 114
 115 ****************************************************************************/
 116
 117 #include <utmp.h>
 118
 119 #ifdef HAVE_UTMPX_H
 120 #include <utmpx.h>
 121 #endif
 122
 123 /* BSD systems: some may need lastlog.h (SunOS 4), some may not (FreeBSD) */
 124 /* Some System-V systems (e.g. Solaris 2) declare this too. */
 125 #ifdef HAVE_LASTLOG_H
 126 #include <lastlog.h>
 127 #endif
 128
 129 /****************************************************************************
 130  Obtain/release a small number (0 upwards) unique within and across smbds.
 131 ****************************************************************************/
 132 /*
 133  * Need a "small" number to represent this connection, unique within this
 134  * smbd and across all smbds.
 135  *
 136  * claim:
 137  *      Start at 0, hunt up for free, unique number "unum" by attempting to
 138  *      store it as a key in a tdb database:
 139  *              key: unum               data: pid+conn
 140  *      Also store its inverse, ready for yield function:
 141  *              key: pid+conn           data: unum
 142  *
 143  * yield:
 144  *      Find key: pid+conn; data is unum;  delete record
 145  *      Find key: unum ; delete record.
 146  *
 147  * Comment:
 148  *      The claim algorithm (a "for" loop attempting to store numbers in a tdb
 149  *      database) will be increasingly inefficient with larger numbers of
 150  *      connections.  Is it possible to write a suitable primitive within tdb?
 151  *
 152  *      However, by also storing the inverse key/data pair, we at least make
 153  *      the yield algorithm efficient.
 154  */
 155
 156 /****************************************************************************
 157  Default paths to various {u,w}tmp{,x} files.
 158 ****************************************************************************/
 159
 160 #ifdef  HAVE_UTMPX_H
 161
 162 static const char *ux_pathname =
 163 # if defined (UTMPX_FILE)
 164         UTMPX_FILE ;
 165 # elif defined (_UTMPX_FILE)
 166         _UTMPX_FILE ;
 167 # elif defined (_PATH_UTMPX)
 168         _PATH_UTMPX ;
 169 # else
 170         "" ;
 171 # endif
 172
 173 static const char *wx_pathname =
 174 # if defined (WTMPX_FILE)
 175         WTMPX_FILE ;
 176 # elif defined (_WTMPX_FILE)
 177         _WTMPX_FILE ;
 178 # elif defined (_PATH_WTMPX)
 179         _PATH_WTMPX ;
 180 # else
 181         "" ;
 182 # endif
 183
 184 #endif  /* HAVE_UTMPX_H */
 185
 186 static const char *ut_pathname =
 187 # if defined (UTMP_FILE)
 188         UTMP_FILE ;
 189 # elif defined (_UTMP_FILE)
 190         _UTMP_FILE ;
 191 # elif defined (_PATH_UTMP)
 192         _PATH_UTMP ;
 193 # else
 194         "" ;
 195 # endif
 196
 197 static const char *wt_pathname =
 198 # if defined (WTMP_FILE)
 199         WTMP_FILE ;
 200 # elif defined (_WTMP_FILE)
 201         _WTMP_FILE ;
 202 # elif defined (_PATH_WTMP)
 203         _PATH_WTMP ;
 204 # else
 205         "" ;
 206 # endif
 207
 208 /* BSD-like systems might want "lastlog" support. */
 209 /* *** Not yet implemented */
 210 #ifndef HAVE_PUTUTLINE          /* see "pututline_my()" */
 211 static const char *ll_pathname =
 212 # if defined (_PATH_LASTLOG)    /* what other names (if any?) */
 213         _PATH_LASTLOG ;
 214 # else
 215         "" ;
 216 # endif /* _PATH_LASTLOG */
 217 #endif  /* HAVE_PUTUTLINE */
 218
 219 /*
 220  * Get name of {u,w}tmp{,x} file.
 221  *      return: fname contains filename
 222  *              Possibly empty if this code not yet ported to this system.
 223  *
 224  * utmp{,x}:  try "utmp dir", then default (a define)
 225  * wtmp{,x}:  try "wtmp dir", then "utmp dir", then default (a define)
 226  */
 227 static void uw_pathname(pstring fname, const char *uw_name, const char *uw_default)
 228 {
 229         pstring dirname;
 230
 231         pstrcpy(dirname, "");
 232
 233         /* For w-files, first look for explicit "wtmp dir" */
 234         if (uw_name[0] == 'w') {
 235                 pstrcpy(dirname,lp_wtmpdir());
 236                 trim_string(dirname,"","/");
 237         }
 238
 239         /* For u-files and non-explicit w-dir, look for "utmp dir" */
 240         if (dirname == 0 || strlen(dirname) == 0) {
 241                 pstrcpy(dirname,lp_utmpdir());
 242                 trim_string(dirname,"","/");
 243         }
 244
 245         /* If explicit directory above, use it */
 246         if (dirname != 0 && strlen(dirname) != 0) {
 247                 pstrcpy(fname, dirname);
 248                 pstrcat(fname, "/");
 249                 pstrcat(fname, uw_name);
 250                 return;
 251         }
 252
 253         /* No explicit directory: attempt to use default paths */
 254         if (strlen(uw_default) == 0) {
 255                 /* No explicit setting, no known default.
 256                  * Has it yet been ported to this OS?
 257                  */
 258                 DEBUG(2,("uw_pathname: unable to determine pathname\n"));
 259         }
 260         pstrcpy(fname, uw_default);
 261 }
 262
 263 #ifndef HAVE_PUTUTLINE
 264
 265 /****************************************************************************
 266  Update utmp file directly.  No subroutine interface: probably a BSD system.
 267 ****************************************************************************/
 268
 269 static void pututline_my(pstring uname, struct utmp *u, BOOL claim)
 270 {
 271         DEBUG(1,("pututline_my: not yet implemented\n"));
 272         /* BSD implementor: may want to consider (or not) adjusting "lastlog" */
 273 }
 274 #endif /* HAVE_PUTUTLINE */
 275
 276 #ifndef HAVE_UPDWTMP
 277
 278 /****************************************************************************
 279  Update wtmp file directly.  No subroutine interface: probably a BSD system.
 280  Credit: Michail Vidiassov <master@iaas.msu.ru>
 281 ****************************************************************************/
 282
 283 static void updwtmp_my(pstring wname, struct utmp *u, BOOL claim)
 284 {
 285         int fd;
 286         struct stat buf;
 287
 288         if (! claim) {
 289                 /*
 290                  * BSD-like systems:
 291                  *      may use empty ut_name to distinguish a logout record.
 292                  *
 293                  * May need "if defined(SUNOS4)" etc. around some of these,
 294                  * but try to avoid if possible.
 295                  *
 296                  * SunOS 4:
 297                  *      man page indicates ut_name and ut_host both NULL
 298                  * FreeBSD 4.0:
 299                  *      man page appears not to specify (hints non-NULL)
 300                  *      A correspondent suggest at least ut_name should be NULL
 301                  */
 302                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 303                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 304         }
 305         /* Stolen from logwtmp function in libutil.
 306          * May be more locking/blocking is needed?
 307          */
 308         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 309                 return;
 310         if (fstat(fd, &buf) == 0) {
 311                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 312                 (void) ftruncate(fd, buf.st_size);
 313         }
 314         (void) close(fd);
 315 }
 316 #endif /* HAVE_UPDWTMP */
 317
 318 /****************************************************************************
 319  Update via utmp/wtmp (not utmpx/wtmpx).
 320 ****************************************************************************/
 321
 322 static void utmp_nox_update(struct utmp *u, BOOL claim)
 323 {
 324         pstring uname, wname;
 325 #if defined(PUTUTLINE_RETURNS_UTMP)
 326         struct utmp *urc;
 327 #endif /* PUTUTLINE_RETURNS_UTMP */
 328
 329         uw_pathname(uname, "utmp", ut_pathname);
 330         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 331
 332 #ifdef HAVE_PUTUTLINE
 333         if (strlen(uname) != 0) {
 334                 utmpname(uname);
 335         }
 336
 337 # if defined(PUTUTLINE_RETURNS_UTMP)
 338         setutent();
 339         urc = pututline(u);
 340         endutent();
 341         if (urc == NULL) {
 342                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 343                 return;
 344         }
 345 # else  /* PUTUTLINE_RETURNS_UTMP */
 346         setutent();
 347         pututline(u);
 348         endutent();
 349 # endif /* PUTUTLINE_RETURNS_UTMP */
 350
 351 #else   /* HAVE_PUTUTLINE */
 352         if (strlen(uname) != 0) {
 353                 pututline_my(uname, u, claim);
 354         }
 355 #endif /* HAVE_PUTUTLINE */
 356
 357         uw_pathname(wname, "wtmp", wt_pathname);
 358         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 359         if (strlen(wname) != 0) {
 360 #ifdef HAVE_UPDWTMP
 361                 updwtmp(wname, u);
 362                 /*
 363                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 364                  * At least one OS, Solaris 2.x declares the former in the
 365                  * "utmpx" (latter) file and context.
 366                  * In the Solaris case this is irrelevant: it has both and
 367                  * we always prefer the "x" case, so doesn't come here.
 368                  * But are there other systems, with no "x", which lack
 369                  * updwtmp() perhaps?
 370                  */
 371 #else
 372                 updwtmp_my(wname, u, claim);
 373 #endif /* HAVE_UPDWTMP */
 374         }
 375 }
 376
 377 /****************************************************************************
 378  Copy a string in the utmp structure.
 379 ****************************************************************************/
 380
 381 static void utmp_strcpy(char *dest, const char *src, size_t n)
 382 {
 383         size_t len = 0;
 384
 385         memset(dest, '\0', n);
 386         if (src)
 387                 len = strlen(src);
 388         if (len >= n) {
 389                 memcpy(dest, src, n);
 390         } else {
 391                 if (len)
 392                         memcpy(dest, src, len);
 393         }
 394 }
 395
 396 /****************************************************************************
 397  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 398 ****************************************************************************/
 399
 400 static void sys_utmp_update(struct utmp *u, const char *hostname, BOOL claim)
 401 {
 402 #if !defined(HAVE_UTMPX_H)
 403         /* No utmpx stuff.  Drop to non-x stuff */
 404         utmp_nox_update(u, claim);
 405 #elif !defined(HAVE_PUTUTXLINE)
 406         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 407         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 408         utmp_nox_update(u, claim);
 409 #elif !defined(HAVE_GETUTMPX)
 410         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 411         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 412         utmp_nox_update(u, claim);
 413 #else
 414         pstring uname, wname;
 415         struct utmpx ux, *uxrc;
 416
 417         getutmpx(u, &ux);
 418
 419 #if defined(HAVE_UX_UT_SYSLEN)
 420         if (hostname)
 421                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 422         else
 423                 ux.ut_syslen = 0;
 424 #endif
 425         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 426
 427         uw_pathname(uname, "utmpx", ux_pathname);
 428         uw_pathname(wname, "wtmpx", wx_pathname);
 429         DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 430         /*
 431          * Check for either uname or wname being empty.
 432          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 433          * define default filenames.
 434          * Also, our local installation has not provided an override.
 435          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 436          */
 437         if ((strlen(uname) == 0) || (strlen(wname) == 0)) {
 438                 utmp_nox_update(u, claim);
 439         } else {
 440                 utmpxname(uname);
 441                 setutxent();
 442                 uxrc = pututxline(&ux);
 443                 endutxent();
 444                 if (uxrc == NULL) {
 445                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 446                         return;
 447                 }
 448                 updwtmpx(wname, &ux);
 449         }
 450 #endif /* HAVE_UTMPX_H */
 451 }
 452
 453 #if defined(HAVE_UT_UT_ID)
 454 /****************************************************************************
 455  Encode the unique connection number into "ut_id".
 456 ****************************************************************************/
 457
 458 static int ut_id_encode(int i, char *fourbyte)
 459 {
 460         int nbase;
 461         char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 462
 463         fourbyte[0] = 'S';
 464         fourbyte[1] = 'M';
 465
 466 /*
 467  * Encode remaining 2 bytes from 'i'.
 468  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 469  * Example: digits would produce the base-10 numbers from '001'.
 470  */
 471         nbase = strlen(ut_id_encstr);
 472
 473         fourbyte[3] = ut_id_encstr[i % nbase];
 474         i /= nbase;
 475         fourbyte[2] = ut_id_encstr[i % nbase];
 476         i /= nbase;
 477
 478         return(i);      /* 0: good; else overflow */
 479 }
 480 #endif /* defined(HAVE_UT_UT_ID) */
 481
 482
 483 /*
 484   fill a system utmp structure given all the info we can gather
 485 */
 486 static BOOL sys_utmp_fill(struct utmp *u,
 487                           const char *username, const char *hostname,
 488                           const char *id_str, int id_num)
 489 {
 490         struct timeval timeval;
 491
 492         /*
 493          * ut_name, ut_user:
 494          *      Several (all?) systems seems to define one as the other.
 495          *      It is easier and clearer simply to let the following take its course,
 496          *      rather than to try to detect and optimise.
 497          */
 498 #if defined(HAVE_UT_UT_USER)
 499         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 500 #elif defined(HAVE_UT_UT_NAME)
 501         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 502 #endif
 503
 504         /*
 505          * ut_line:
 506          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 507          *
 508          * Temporary variable "line_tmp" avoids trouble:
 509          * o  with unwanted trailing NULL if ut_line full;
 510          * o  with overflow if ut_line would be more than full.
 511          */
 512         if (strlen(id_str) > sizeof(u->ut_line)) {
 513                 DEBUG(1,("id_str [%s] is too long for %d char utmp field\n",
 514                          id_str, sizeof(u->ut_line)));
 515                 return False;
 516         }
 517         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 518
 519 #if defined(HAVE_UT_UT_PID)
 520         u->ut_pid = sys_getpid();
 521 #endif
 522
 523 /*
 524  * ut_time, ut_tv:
 525  *      Some have one, some the other.  Many have both, but defined (aliased).
 526  *      It is easier and clearer simply to let the following take its course.
 527  *      But note that we do the more precise ut_tv as the final assignment.
 528  */
 529 #if defined(HAVE_UT_UT_TIME)
 530         gettimeofday(&timeval, NULL);
 531         u->ut_time = timeval.tv_sec;
 532 #elif defined(HAVE_UT_UT_TV)
 533         gettimeofday(&timeval, NULL);
 534         u->ut_tv = timeval;
 535 #else
 536 #error "with-utmp must have UT_TIME or UT_TV"
 537 #endif
 538
 539 #if defined(HAVE_UT_UT_HOST)
 540         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 541 #endif
 542
 543 #if defined(HAVE_UT_UT_ADDR)
 544         /*
 545          * "(unsigned long) ut_addr" apparently exists on at least HP-UX 10.20.
 546          * Volunteer to implement, please ...
 547          */
 548 #endif
 549
 550 #if defined(HAVE_UT_UT_ID)
 551         if (ut_id_encode(id_num, u->ut_id) != 0) {
 552                 DEBUG(1,("utmp_fill: cannot encode id %d\n", id_num));
 553                 return False;
 554         }
 555 #endif
 556
 557         return True;
 558 }
 559
 560 /****************************************************************************
 561  Close a connection.
 562 ****************************************************************************/
 563
 564 void sys_utmp_yield(const char *username, const char *hostname,
 565                     const char *id_str, int id_num)
 566 {
 567         struct utmp u;
 568
 569         ZERO_STRUCT(u);
 570
 571 #if defined(HAVE_UT_UT_EXIT)
 572         u.ut_exit.e_termination = 0;
 573         u.ut_exit.e_exit = 0;
 574 #endif
 575
 576 #if defined(HAVE_UT_UT_TYPE)
 577         u.ut_type = DEAD_PROCESS;
 578 #endif
 579
 580         if (!sys_utmp_fill(&u, username, hostname, id_str, id_num)) return;
 581
 582         sys_utmp_update(&u, NULL, False);
 583 }
 584
 585 /****************************************************************************
 586  Claim a entry in whatever utmp system the OS uses.
 587 ****************************************************************************/
 588
 589 void sys_utmp_claim(const char *username, const char *hostname,
 590                     const char *id_str, int id_num)
 591 {
 592         struct utmp u;
 593
 594         ZERO_STRUCT(u);
 595
 596 #if defined(HAVE_UT_UT_TYPE)
 597         u.ut_type = USER_PROCESS;
 598 #endif
 599
 600         if (!sys_utmp_fill(&u, username, hostname, id_str, id_num)) return;
 601
 602         sys_utmp_update(&u, hostname, True);
 603 }
 604
 605 #else /* WITH_UTMP */
 606  void dummy_utmp(void) {}
 607 #endif