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_string(dirname,"","/");
 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_string(dirname,"","/");
 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                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 287                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 288         }
 289         /* Stolen from logwtmp function in libutil.
 290          * May be more locking/blocking is needed?
 291          */
 292         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 293                 return;
 294         if (fstat(fd, &buf) == 0) {
 295                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 296                 (void) ftruncate(fd, buf.st_size);
 297         }
 298         (void) close(fd);
 299 }
 300 #endif /* HAVE_UPDWTMP */
 301
 302 /****************************************************************************
 303  Update via utmp/wtmp (not utmpx/wtmpx).
 304 ****************************************************************************/
 305
 306 static void utmp_nox_update(struct utmp *u, BOOL claim)
 307 {
 308         pstring uname, wname;
 309 #if defined(PUTUTLINE_RETURNS_UTMP)
 310         struct utmp *urc;
 311 #endif /* PUTUTLINE_RETURNS_UTMP */
 312
 313         uw_pathname(uname, "utmp", ut_pathname);
 314         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 315
 316 #ifdef HAVE_PUTUTLINE
 317         if (strlen(uname) != 0) {
 318                 utmpname(uname);
 319         }
 320
 321 # if defined(PUTUTLINE_RETURNS_UTMP)
 322         setutent();
 323         urc = pututline(u);
 324         endutent();
 325         if (urc == NULL) {
 326                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 327                 return;
 328         }
 329 # else  /* PUTUTLINE_RETURNS_UTMP */
 330         setutent();
 331         pututline(u);
 332         endutent();
 333 # endif /* PUTUTLINE_RETURNS_UTMP */
 334
 335 #else   /* HAVE_PUTUTLINE */
 336         if (strlen(uname) != 0) {
 337                 pututline_my(uname, u, claim);
 338         }
 339 #endif /* HAVE_PUTUTLINE */
 340
 341         uw_pathname(wname, "wtmp", wt_pathname);
 342         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 343         if (strlen(wname) != 0) {
 344 #ifdef HAVE_UPDWTMP
 345                 updwtmp(wname, u);
 346                 /*
 347                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 348                  * At least one OS, Solaris 2.x declares the former in the
 349                  * "utmpx" (latter) file and context.
 350                  * In the Solaris case this is irrelevant: it has both and
 351                  * we always prefer the "x" case, so doesn't come here.
 352                  * But are there other systems, with no "x", which lack
 353                  * updwtmp() perhaps?
 354                  */
 355 #else
 356                 updwtmp_my(wname, u, claim);
 357 #endif /* HAVE_UPDWTMP */
 358         }
 359 }
 360
 361 /****************************************************************************
 362  Copy a string in the utmp structure.
 363 ****************************************************************************/
 364
 365 static void utmp_strcpy(char *dest, const char *src, size_t n)
 366 {
 367         size_t len = 0;
 368
 369         memset(dest, '\0', n);
 370         if (src)
 371                 len = strlen(src);
 372         if (len >= n) {
 373                 memcpy(dest, src, n);
 374         } else {
 375                 if (len)
 376                         memcpy(dest, src, len);
 377         }
 378 }
 379
 380 /****************************************************************************
 381  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 382 ****************************************************************************/
 383
 384 static void sys_utmp_update(struct utmp *u, const char *hostname, BOOL claim)
 385 {
 386 #if !defined(HAVE_UTMPX_H)
 387         /* No utmpx stuff.  Drop to non-x stuff */
 388         utmp_nox_update(u, claim);
 389 #elif !defined(HAVE_PUTUTXLINE)
 390         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 391         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 392         utmp_nox_update(u, claim);
 393 #elif !defined(HAVE_GETUTMPX)
 394         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 395         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 396         utmp_nox_update(u, claim);
 397 #else
 398         pstring uname, wname;
 399         struct utmpx ux, *uxrc;
 400
 401         getutmpx(u, &ux);
 402
 403 #if defined(HAVE_UX_UT_SYSLEN)
 404         if (hostname)
 405                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 406         else
 407                 ux.ut_syslen = 0;
 408 #endif
 409         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 410
 411         uw_pathname(uname, "utmpx", ux_pathname);
 412         uw_pathname(wname, "wtmpx", wx_pathname);
 413         DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 414         /*
 415          * Check for either uname or wname being empty.
 416          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 417          * define default filenames.
 418          * Also, our local installation has not provided an override.
 419          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 420          */
 421         if ((strlen(uname) == 0) || (strlen(wname) == 0)) {
 422                 utmp_nox_update(u, claim);
 423         } else {
 424                 utmpxname(uname);
 425                 setutxent();
 426                 uxrc = pututxline(&ux);
 427                 endutxent();
 428                 if (uxrc == NULL) {
 429                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 430                         return;
 431                 }
 432                 updwtmpx(wname, &ux);
 433         }
 434 #endif /* HAVE_UTMPX_H */
 435 }
 436
 437 #if defined(HAVE_UT_UT_ID)
 438 /****************************************************************************
 439  Encode the unique connection number into "ut_id".
 440 ****************************************************************************/
 441
 442 static int ut_id_encode(int i, char *fourbyte)
 443 {
 444         int nbase;
 445         const char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 446
 447         fourbyte[0] = 'S';
 448         fourbyte[1] = 'M';
 449
 450 /*
 451  * Encode remaining 2 bytes from 'i'.
 452  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 453  * Example: digits would produce the base-10 numbers from '001'.
 454  */
 455         nbase = strlen(ut_id_encstr);
 456
 457         fourbyte[3] = ut_id_encstr[i % nbase];
 458         i /= nbase;
 459         fourbyte[2] = ut_id_encstr[i % nbase];
 460         i /= nbase;
 461
 462         return(i);      /* 0: good; else overflow */
 463 }
 464 #endif /* defined(HAVE_UT_UT_ID) */
 465
 466
 467 /*
 468   fill a system utmp structure given all the info we can gather
 469 */
 470 static BOOL sys_utmp_fill(struct utmp *u,
 471                           const char *username, const char *hostname,
 472                           struct in_addr *ipaddr,
 473                           const char *id_str, int id_num)
 474 {
 475         struct timeval timeval;
 476
 477         /*
 478          * ut_name, ut_user:
 479          *      Several (all?) systems seems to define one as the other.
 480          *      It is easier and clearer simply to let the following take its course,
 481          *      rather than to try to detect and optimise.
 482          */
 483 #if defined(HAVE_UT_UT_USER)
 484         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 485 #elif defined(HAVE_UT_UT_NAME)
 486         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 487 #endif
 488
 489         /*
 490          * ut_line:
 491          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 492          */
 493         if (strlen(id_str) > sizeof(u->ut_line)) {
 494                 DEBUG(1,("id_str [%s] is too long for %d char utmp field\n",
 495                          id_str, sizeof(u->ut_line)));
 496                 return False;
 497         }
 498         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 499
 500 #if defined(HAVE_UT_UT_PID)
 501         u->ut_pid = sys_getpid();
 502 #endif
 503
 504 /*
 505  * ut_time, ut_tv:
 506  *      Some have one, some the other.  Many have both, but defined (aliased).
 507  *      It is easier and clearer simply to let the following take its course.
 508  *      But note that we do the more precise ut_tv as the final assignment.
 509  */
 510 #if defined(HAVE_UT_UT_TIME)
 511         gettimeofday(&timeval, NULL);
 512         u->ut_time = timeval.tv_sec;
 513 #elif defined(HAVE_UT_UT_TV)
 514         gettimeofday(&timeval, NULL);
 515         u->ut_tv = timeval;
 516 #else
 517 #error "with-utmp must have UT_TIME or UT_TV"
 518 #endif
 519
 520 #if defined(HAVE_UT_UT_HOST)
 521         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 522 #endif
 523 #if defined(HAVE_UT_UT_ADDR)
 524         if (ipaddr)
 525                 u->ut_addr = ipaddr->s_addr;
 526         /*
 527          * "(unsigned long) ut_addr" apparently exists on at least HP-UX 10.20.
 528          * Volunteer to implement, please ...
 529          */
 530 #endif
 531
 532 #if defined(HAVE_UT_UT_ID)
 533         if (ut_id_encode(id_num, u->ut_id) != 0) {
 534                 DEBUG(1,("utmp_fill: cannot encode id %d\n", id_num));
 535                 return False;
 536         }
 537 #endif
 538
 539         return True;
 540 }
 541
 542 /****************************************************************************
 543  Close a connection.
 544 ****************************************************************************/
 545
 546 void sys_utmp_yield(const char *username, const char *hostname,
 547                     struct in_addr *ipaddr,
 548                     const char *id_str, int id_num)
 549 {
 550         struct utmp u;
 551
 552         ZERO_STRUCT(u);
 553
 554 #if defined(HAVE_UT_UT_EXIT)
 555         u.ut_exit.e_termination = 0;
 556         u.ut_exit.e_exit = 0;
 557 #endif
 558
 559 #if defined(HAVE_UT_UT_TYPE)
 560         u.ut_type = DEAD_PROCESS;
 561 #endif
 562
 563         if (!sys_utmp_fill(&u, username, hostname, ipaddr, id_str, id_num)) return;
 564
 565         sys_utmp_update(&u, NULL, False);
 566 }
 567
 568 /****************************************************************************
 569  Claim a entry in whatever utmp system the OS uses.
 570 ****************************************************************************/
 571
 572 void sys_utmp_claim(const char *username, const char *hostname,
 573                     struct in_addr *ipaddr,
 574                     const char *id_str, int id_num)
 575 {
 576         struct utmp u;
 577
 578         ZERO_STRUCT(u);
 579
 580 #if defined(HAVE_UT_UT_TYPE)
 581         u.ut_type = USER_PROCESS;
 582 #endif
 583
 584         if (!sys_utmp_fill(&u, username, hostname, ipaddr, id_str, id_num)) return;
 585
 586         sys_utmp_update(&u, hostname, True);
 587 }
 588
 589 #endif /* WITH_UTMP */