source/smbd/utmp.c

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