source3/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 3 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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 /****************************************************************************
  24 Reflect connection status in utmp/wtmp files.
  25         T.D.Lee@durham.ac.uk  September 1999
  26
  27         With grateful thanks since then to many who have helped port it to
  28         different operating systems.  The variety of OS quirks thereby
  29         uncovered is amazing...
  30
  31 Hints for porting:
  32         o  Always attempt to use programmatic interface (pututline() etc.)
  33            Indeed, at present only programmatic use is supported.
  34         o  The only currently supported programmatic interface to "wtmp{,x}"
  35            is through "updwtmp*()" routines.
  36         o  The "x" (utmpx/wtmpx; HAVE_UTMPX_H) seems preferable.
  37         o  The HAVE_* items should identify supported features.
  38         o  If at all possible, avoid "if defined(MY-OS)" constructions.
  39
  40 OS observations and status:
  41         Almost every OS seems to have its own quirks.
  42
  43         Solaris 2.x:
  44                 Tested on 2.6 and 2.7; should be OK on other flavours.
  45         AIX:
  46                 Apparently has utmpx.h but doesn't implement.
  47         OSF:
  48                 Has utmpx.h, but (e.g.) no "getutmpx()".  (Is this like AIX ?)
  49         Redhat 6:
  50                 utmpx.h seems not to set default filenames.  non-x better.
  51         IRIX 6.5:
  52                 Not tested.  Appears to have "x".
  53         HP-UX 9.x:
  54                 Not tested.  Appears to lack "x".
  55         HP-UX 10.x:
  56                 Not tested.
  57                 "updwtmp*()" routines seem absent, so no current wtmp* support.
  58                 Has "ut_addr": probably trivial to implement (although remember
  59                 that IPv6 is coming...).
  60
  61         FreeBSD:
  62                 No "putut*()" type of interface.
  63                 No "ut_type" and associated defines.
  64                 Write files directly.  Alternatively use its login(3)/logout(3).
  65         SunOS 4:
  66                 Not tested.  Resembles FreeBSD, but no login()/logout().
  67
  68 lastlog:
  69         Should "lastlog" files, if any, be updated?
  70         BSD systems (SunOS 4, FreeBSD):
  71                 o  Prominent mention on man pages.
  72         System-V (e.g. Solaris 2):
  73                 o  No mention on man pages, even under "man -k".
  74                 o  Has a "/var/adm/lastlog" file, but pututxline() etc. seem
  75                    not to touch it.
  76                 o  Despite downplaying (above), nevertheless has <lastlog.h>.
  77         So perhaps UN*X "lastlog" facility is intended for tty/terminal only?
  78
  79 Notes:
  80         Each connection requires a small number (starting at 0, working up)
  81         to represent the line.  This must be unique within and across all
  82         smbd processes.  It is the 'id_num' from Samba's session.c code.
  83
  84         The 4 byte 'ut_id' component is vital to distinguish connections,
  85         of which there could be several hundred or even thousand.
  86         Entries seem to be printable characters, with optional NULL pads.
  87
  88         We need to be distinct from other entries in utmp/wtmp.
  89
  90         Observed things: therefore avoid them.  Add to this list please.
  91         From Solaris 2.x (because that's what I have):
  92                 'sN'    : run-levels; N: [0-9]
  93                 'co'    : console
  94                 'CC'    : arbitrary things;  C: [a-z]
  95                 'rXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
  96                 'tXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
  97                 '/NNN'  : Solaris CDE
  98                 'ftpZ'  : ftp (Z is the number 255, aka 0377, aka 0xff)
  99         Mostly a record uses the same 'ut_id' in both "utmp" and "wtmp",
 100         but differences have been seen.
 101
 102         Arbitrarily I have chosen to use a distinctive 'SM' for the
 103         first two bytes.
 104
 105         The remaining two bytes encode the session 'id_num' (see above).
 106         Our caller (session.c) should note our 16-bit limitation.
 107
 108 ****************************************************************************/
 109
 110 #ifndef WITH_UTMP
 111 /*
 112  * Not WITH_UTMP?  Simply supply dummy routines.
 113  */
 114
 115 void sys_utmp_claim(const char *username, const char *hostname,
 116                         const char *ip_addr_str,
 117                         const char *id_str, int id_num)
 118 {}
 119
 120 void sys_utmp_yield(const char *username, const char *hostname,
 121                         const char *ip_addr_str,
 122                         const char *id_str, int id_num)
 123 {}
 124
 125 #else /* WITH_UTMP */
 126
 127 #include <utmp.h>
 128
 129 #ifdef HAVE_UTMPX_H
 130 #include <utmpx.h>
 131 #endif
 132
 133 /* BSD systems: some may need lastlog.h (SunOS 4), some may not (FreeBSD) */
 134 /* Some System-V systems (e.g. Solaris 2) declare this too. */
 135 #ifdef HAVE_LASTLOG_H
 136 #include <lastlog.h>
 137 #endif
 138
 139 /****************************************************************************
 140  Default paths to various {u,w}tmp{,x} files.
 141 ****************************************************************************/
 142
 143 #ifdef  HAVE_UTMPX_H
 144
 145 static const char *ux_pathname =
 146 # if defined (UTMPX_FILE)
 147         UTMPX_FILE ;
 148 # elif defined (_UTMPX_FILE)
 149         _UTMPX_FILE ;
 150 # elif defined (_PATH_UTMPX)
 151         _PATH_UTMPX ;
 152 # else
 153         "" ;
 154 # endif
 155
 156 static const char *wx_pathname =
 157 # if defined (WTMPX_FILE)
 158         WTMPX_FILE ;
 159 # elif defined (_WTMPX_FILE)
 160         _WTMPX_FILE ;
 161 # elif defined (_PATH_WTMPX)
 162         _PATH_WTMPX ;
 163 # else
 164         "" ;
 165 # endif
 166
 167 #endif  /* HAVE_UTMPX_H */
 168
 169 static const char *ut_pathname =
 170 # if defined (UTMP_FILE)
 171         UTMP_FILE ;
 172 # elif defined (_UTMP_FILE)
 173         _UTMP_FILE ;
 174 # elif defined (_PATH_UTMP)
 175         _PATH_UTMP ;
 176 # else
 177         "" ;
 178 # endif
 179
 180 static const char *wt_pathname =
 181 # if defined (WTMP_FILE)
 182         WTMP_FILE ;
 183 # elif defined (_WTMP_FILE)
 184         _WTMP_FILE ;
 185 # elif defined (_PATH_WTMP)
 186         _PATH_WTMP ;
 187 # else
 188         "" ;
 189 # endif
 190
 191 /* BSD-like systems might want "lastlog" support. */
 192 /* *** Not yet implemented */
 193 #ifndef HAVE_PUTUTLINE          /* see "pututline_my()" */
 194 static const char *ll_pathname =
 195 # if defined (_PATH_LASTLOG)    /* what other names (if any?) */
 196         _PATH_LASTLOG ;
 197 # else
 198         "" ;
 199 # endif /* _PATH_LASTLOG */
 200 #endif  /* HAVE_PUTUTLINE */
 201
 202 /*
 203  * Get name of {u,w}tmp{,x} file.
 204  *      return: fname contains filename
 205  *              Possibly empty if this code not yet ported to this system.
 206  *
 207  * utmp{,x}:  try "utmp dir", then default (a define)
 208  * wtmp{,x}:  try "wtmp dir", then "utmp dir", then default (a define)
 209  */
 210 static void uw_pathname(pstring fname, const char *uw_name, const char *uw_default)
 211 {
 212         pstring dirname;
 213
 214         pstrcpy(dirname, "");
 215
 216         /* For w-files, first look for explicit "wtmp dir" */
 217         if (uw_name[0] == 'w') {
 218                 pstrcpy(dirname,lp_wtmpdir());
 219                 trim_char(dirname,'\0','/');
 220         }
 221
 222         /* For u-files and non-explicit w-dir, look for "utmp dir" */
 223         if (dirname == 0 || strlen(dirname) == 0) {
 224                 pstrcpy(dirname,lp_utmpdir());
 225                 trim_char(dirname,'\0','/');
 226         }
 227
 228         /* If explicit directory above, use it */
 229         if (dirname != 0 && strlen(dirname) != 0) {
 230                 pstrcpy(fname, dirname);
 231                 pstrcat(fname, "/");
 232                 pstrcat(fname, uw_name);
 233                 return;
 234         }
 235
 236         /* No explicit directory: attempt to use default paths */
 237         if (strlen(uw_default) == 0) {
 238                 /* No explicit setting, no known default.
 239                  * Has it yet been ported to this OS?
 240                  */
 241                 DEBUG(2,("uw_pathname: unable to determine pathname\n"));
 242         }
 243         pstrcpy(fname, uw_default);
 244 }
 245
 246 #ifndef HAVE_PUTUTLINE
 247
 248 /****************************************************************************
 249  Update utmp file directly.  No subroutine interface: probably a BSD system.
 250 ****************************************************************************/
 251
 252 static void pututline_my(pstring uname, struct utmp *u, BOOL claim)
 253 {
 254         DEBUG(1,("pututline_my: not yet implemented\n"));
 255         /* BSD implementor: may want to consider (or not) adjusting "lastlog" */
 256 }
 257 #endif /* HAVE_PUTUTLINE */
 258
 259 #ifndef HAVE_UPDWTMP
 260
 261 /****************************************************************************
 262  Update wtmp file directly.  No subroutine interface: probably a BSD system.
 263  Credit: Michail Vidiassov <master@iaas.msu.ru>
 264 ****************************************************************************/
 265
 266 static void updwtmp_my(pstring wname, struct utmp *u, BOOL claim)
 267 {
 268         int fd;
 269         struct stat buf;
 270
 271         if (! claim) {
 272                 /*
 273                  * BSD-like systems:
 274                  *      may use empty ut_name to distinguish a logout record.
 275                  *
 276                  * May need "if defined(SUNOS4)" etc. around some of these,
 277                  * but try to avoid if possible.
 278                  *
 279                  * SunOS 4:
 280                  *      man page indicates ut_name and ut_host both NULL
 281                  * FreeBSD 4.0:
 282                  *      man page appears not to specify (hints non-NULL)
 283                  *      A correspondent suggest at least ut_name should be NULL
 284                  */
 285 #if defined(HAVE_UT_UT_NAME)
 286                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 287 #endif
 288 #if defined(HAVE_UT_UT_HOST)
 289                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 290 #endif
 291         }
 292         /* Stolen from logwtmp function in libutil.
 293          * May be more locking/blocking is needed?
 294          */
 295         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 296                 return;
 297         if (fstat(fd, &buf) == 0) {
 298                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 299                 (void) ftruncate(fd, buf.st_size);
 300         }
 301         (void) close(fd);
 302 }
 303 #endif /* HAVE_UPDWTMP */
 304
 305 /****************************************************************************
 306  Update via utmp/wtmp (not utmpx/wtmpx).
 307 ****************************************************************************/
 308
 309 static void utmp_nox_update(struct utmp *u, BOOL claim)
 310 {
 311         pstring uname, wname;
 312 #if defined(PUTUTLINE_RETURNS_UTMP)
 313         struct utmp *urc;
 314 #endif /* PUTUTLINE_RETURNS_UTMP */
 315
 316         uw_pathname(uname, "utmp", ut_pathname);
 317         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 318
 319 #ifdef HAVE_PUTUTLINE
 320         if (strlen(uname) != 0) {
 321                 utmpname(uname);
 322         }
 323
 324 # if defined(PUTUTLINE_RETURNS_UTMP)
 325         setutent();
 326         urc = pututline(u);
 327         endutent();
 328         if (urc == NULL) {
 329                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 330                 return;
 331         }
 332 # else  /* PUTUTLINE_RETURNS_UTMP */
 333         setutent();
 334         pututline(u);
 335         endutent();
 336 # endif /* PUTUTLINE_RETURNS_UTMP */
 337
 338 #else   /* HAVE_PUTUTLINE */
 339         if (strlen(uname) != 0) {
 340                 pututline_my(uname, u, claim);
 341         }
 342 #endif /* HAVE_PUTUTLINE */
 343
 344         uw_pathname(wname, "wtmp", wt_pathname);
 345         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 346         if (strlen(wname) != 0) {
 347 #ifdef HAVE_UPDWTMP
 348                 updwtmp(wname, u);
 349                 /*
 350                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 351                  * At least one OS, Solaris 2.x declares the former in the
 352                  * "utmpx" (latter) file and context.
 353                  * In the Solaris case this is irrelevant: it has both and
 354                  * we always prefer the "x" case, so doesn't come here.
 355                  * But are there other systems, with no "x", which lack
 356                  * updwtmp() perhaps?
 357                  */
 358 #else
 359                 updwtmp_my(wname, u, claim);
 360 #endif /* HAVE_UPDWTMP */
 361         }
 362 }
 363
 364 /****************************************************************************
 365  Copy a string in the utmp structure.
 366 ****************************************************************************/
 367
 368 static void utmp_strcpy(char *dest, const char *src, size_t n)
 369 {
 370         size_t len = 0;
 371
 372         memset(dest, '\0', n);
 373         if (src)
 374                 len = strlen(src);
 375         if (len >= n) {
 376                 memcpy(dest, src, n);
 377         } else {
 378                 if (len)
 379                         memcpy(dest, src, len);
 380         }
 381 }
 382
 383 /****************************************************************************
 384  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 385 ****************************************************************************/
 386
 387 static void sys_utmp_update(struct utmp *u, const char *hostname, BOOL claim)
 388 {
 389 #if !defined(HAVE_UTMPX_H)
 390         /* No utmpx stuff.  Drop to non-x stuff */
 391         utmp_nox_update(u, claim);
 392 #elif !defined(HAVE_PUTUTXLINE)
 393         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 394         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 395         utmp_nox_update(u, claim);
 396 #elif !defined(HAVE_GETUTMPX)
 397         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 398         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 399         utmp_nox_update(u, claim);
 400 #else
 401         pstring uname, wname;
 402         struct utmpx ux, *uxrc;
 403
 404         getutmpx(u, &ux);
 405
 406 #if defined(HAVE_UX_UT_SYSLEN)
 407         if (hostname)
 408                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 409         else
 410                 ux.ut_syslen = 0;
 411 #endif
 412 #if defined(HAVE_UT_UT_HOST)
 413         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 414 #endif
 415
 416         uw_pathname(uname, "utmpx", ux_pathname);
 417         uw_pathname(wname, "wtmpx", wx_pathname);
 418         DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 419         /*
 420          * Check for either uname or wname being empty.
 421          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 422          * define default filenames.
 423          * Also, our local installation has not provided an override.
 424          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 425          */
 426         if ((strlen(uname) == 0) || (strlen(wname) == 0)) {
 427                 utmp_nox_update(u, claim);
 428         } else {
 429                 utmpxname(uname);
 430                 setutxent();
 431                 uxrc = pututxline(&ux);
 432                 endutxent();
 433                 if (uxrc == NULL) {
 434                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 435                         return;
 436                 }
 437                 updwtmpx(wname, &ux);
 438         }
 439 #endif /* HAVE_UTMPX_H */
 440 }
 441
 442 #if defined(HAVE_UT_UT_ID)
 443 /****************************************************************************
 444  Encode the unique connection number into "ut_id".
 445 ****************************************************************************/
 446
 447 static int ut_id_encode(int i, char *fourbyte)
 448 {
 449         int nbase;
 450         const char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 451
 452         fourbyte[0] = 'S';
 453         fourbyte[1] = 'M';
 454
 455 /*
 456  * Encode remaining 2 bytes from 'i'.
 457  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 458  * Example: digits would produce the base-10 numbers from '001'.
 459  */
 460         nbase = strlen(ut_id_encstr);
 461
 462         fourbyte[3] = ut_id_encstr[i % nbase];
 463         i /= nbase;
 464         fourbyte[2] = ut_id_encstr[i % nbase];
 465         i /= nbase;
 466
 467         return(i);      /* 0: good; else overflow */
 468 }
 469 #endif /* defined(HAVE_UT_UT_ID) */
 470
 471
 472 /*
 473   fill a system utmp structure given all the info we can gather
 474 */
 475 static BOOL sys_utmp_fill(struct utmp *u,
 476                         const char *username, const char *hostname,
 477                         const char *ip_addr_str,
 478                         const char *id_str, int id_num)
 479 {
 480         struct timeval timeval;
 481
 482         /*
 483          * ut_name, ut_user:
 484          *      Several (all?) systems seems to define one as the other.
 485          *      It is easier and clearer simply to let the following take its course,
 486          *      rather than to try to detect and optimise.
 487          */
 488 #if defined(HAVE_UT_UT_USER)
 489         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 490 #elif defined(HAVE_UT_UT_NAME)
 491         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 492 #endif
 493
 494         /*
 495          * ut_line:
 496          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 497          */
 498         if (strlen(id_str) > sizeof(u->ut_line)) {
 499                 DEBUG(1,("id_str [%s] is too long for %lu char utmp field\n",
 500                          id_str, (unsigned long)sizeof(u->ut_line)));
 501                 return False;
 502         }
 503         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 504
 505 #if defined(HAVE_UT_UT_PID)
 506         u->ut_pid = sys_getpid();
 507 #endif
 508
 509 /*
 510  * ut_time, ut_tv:
 511  *      Some have one, some the other.  Many have both, but defined (aliased).
 512  *      It is easier and clearer simply to let the following take its course.
 513  *      But note that we do the more precise ut_tv as the final assignment.
 514  */
 515 #if defined(HAVE_UT_UT_TIME)
 516         GetTimeOfDay(&timeval);
 517         u->ut_time = timeval.tv_sec;
 518 #elif defined(HAVE_UT_UT_TV)
 519         GetTimeOfDay(&timeval);
 520         u->ut_tv = timeval;
 521 #else
 522 #error "with-utmp must have UT_TIME or UT_TV"
 523 #endif
 524
 525 #if defined(HAVE_UT_UT_HOST)
 526         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 527 #endif
 528 #if defined(AF_INET6) && defined(HAVE_UT_UT_ADDR_V6)
 529         memset(&u->ut_addr_v6, '\0', sizeof(u->ut_addr_v6));
 530         if (ip_addr_str) {
 531                 struct in6_addr addr;
 532                 if (inet_pton(AF_INET6, ip_addr_str, &addr) > 0) {
 533                         memcpy(&u->ut_addr_v6, &addr, sizeof(addr));
 534                 }
 535         }
 536 #elif defined(HAVE_UT_UT_ADDR)
 537         memset(&u->ut_addr, '\0', sizeof(u->ut_addr));
 538         if (ip_addr_str) {
 539                 struct in_addr addr;
 540                 if (inet_pton(AF_INET, ip_addr_str, &addr) > 0) {
 541                         memcpy(&u->ut_addr, &addr, sizeof(addr));
 542                 }
 543         }
 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 *ip_addr_str,
 566                         const char *id_str, int id_num)
 567 {
 568         struct utmp u;
 569
 570         ZERO_STRUCT(u);
 571
 572 #if defined(HAVE_UT_UT_EXIT)
 573         u.ut_exit.e_termination = 0;
 574         u.ut_exit.e_exit = 0;
 575 #endif
 576
 577 #if defined(HAVE_UT_UT_TYPE)
 578         u.ut_type = DEAD_PROCESS;
 579 #endif
 580
 581         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 582                 return;
 583
 584         sys_utmp_update(&u, NULL, False);
 585 }
 586
 587 /****************************************************************************
 588  Claim a entry in whatever utmp system the OS uses.
 589 ****************************************************************************/
 590
 591 void sys_utmp_claim(const char *username, const char *hostname,
 592                         const char *ip_addr_str,
 593                         const char *id_str, int id_num)
 594 {
 595         struct utmp u;
 596
 597         ZERO_STRUCT(u);
 598
 599 #if defined(HAVE_UT_UT_TYPE)
 600         u.ut_type = USER_PROCESS;
 601 #endif
 602
 603         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 604                 return;
 605
 606         sys_utmp_update(&u, hostname, True);
 607 }
 608
 609 #endif /* WITH_UTMP */