usr.bin/who/utmpentry.c

   1 /*      $NetBSD: utmpentry.c,v 1.16 2008/10/28 14:01:46 christos Exp $  */
   2
   3 /*-
   4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Christos Zoulas.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #include <sys/stat.h>
  34
  35 #include <err.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <time.h>
  40
  41 #ifdef SUPPORT_UTMP
  42 #include <utmp.h>
  43 #endif
  44 #ifdef SUPPORT_UTMPX
  45 #include <utmpx.h>
  46 #endif
  47
  48 #include "utmpentry.h"
  49
  50 /* Operations on timespecs. */
  51 #define timespecclear(tsp)      (tsp)->tv_sec = (time_t)((tsp)->tv_nsec = 0L)
  52 #define timespecisset(tsp)      ((tsp)->tv_sec || (tsp)->tv_nsec)
  53 #define timespeccmp(tsp, usp, cmp)                                      \
  54         (((tsp)->tv_sec == (usp)->tv_sec) ?                             \
  55             ((tsp)->tv_nsec cmp (usp)->tv_nsec) :                       \
  56             ((tsp)->tv_sec cmp (usp)->tv_sec))
  57 #define timespecadd(tsp, usp, vsp)                                      \
  58         do {                                                            \
  59                 (vsp)->tv_sec = (tsp)->tv_sec + (usp)->tv_sec;          \
  60                 (vsp)->tv_nsec = (tsp)->tv_nsec + (usp)->tv_nsec;       \
  61                 if ((vsp)->tv_nsec >= 1000000000L) {                    \
  62                         (vsp)->tv_sec++;                                \
  63                         (vsp)->tv_nsec -= 1000000000L;                  \
  64                 }                                                       \
  65         } while (/* CONSTCOND */ 0)
  66 #define timespecsub(tsp, usp, vsp)                                      \
  67         do {                                                            \
  68                 (vsp)->tv_sec = (tsp)->tv_sec - (usp)->tv_sec;          \
  69                 (vsp)->tv_nsec = (tsp)->tv_nsec - (usp)->tv_nsec;       \
  70                 if ((vsp)->tv_nsec < 0) {                               \
  71                         (vsp)->tv_sec--;                                \
  72                         (vsp)->tv_nsec += 1000000000L;                  \
  73                 }                                                       \
  74         } while (/* CONSTCOND */ 0)
  75 #define timespec2ns(x) (((uint64_t)(x)->tv_sec) * 1000000000L + (x)->tv_nsec)
  76
  77
  78 #define COMPILE_ASSERT(x)       _Static_assert(x, "assertion failed")
  79
  80
  81 #ifdef SUPPORT_UTMP
  82 static void getentry(struct utmpentry *, struct utmp *);
  83 static struct timespec utmptime = {0, 0};
  84 #endif
  85 #ifdef SUPPORT_UTMPX
  86 static void getentryx(struct utmpentry *, struct utmpx *);
  87 static struct timespec utmpxtime = {0, 0};
  88 #endif
  89 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
  90 static int setup(const char *);
  91 static void adjust_size(struct utmpentry *e);
  92 #endif
  93
  94 int maxname = 8, maxline = 8, maxhost = 16;
  95 int etype = 1 << USER_PROCESS;
  96 static int numutmp = 0;
  97 static struct utmpentry *ehead;
  98
  99 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
 100 static void
 101 adjust_size(struct utmpentry *e)
 102 {
 103         int max;
 104
 105         if ((max = strlen(e->name)) > maxname)
 106                 maxname = max;
 107         if ((max = strlen(e->line)) > maxline)
 108                 maxline = max;
 109         if ((max = strlen(e->host)) > maxhost)
 110                 maxhost = max;
 111 }
 112
 113 static int
 114 setup(const char *fname)
 115 {
 116         int what = 3;
 117         struct stat st;
 118         const char *sfname;
 119
 120         if (fname == NULL) {
 121 #ifdef SUPPORT_UTMPX
 122                 setutxent();
 123 #endif
 124 #ifdef SUPPORT_UTMP
 125                 setutent();
 126 #endif
 127         } else {
 128                 size_t len = strlen(fname);
 129                 if (len == 0)
 130                         errx(1, "Filename cannot be 0 length.");
 131                 what = fname[len - 1] == 'x' ? 1 : 2;
 132                 if (what == 1) {
 133 #ifdef SUPPORT_UTMPX
 134                         if (utmpxname(fname) == 0)
 135                                 warnx("Cannot set utmpx file to `%s'",
 136                                     fname);
 137 #else
 138                         warnx("utmpx support not compiled in");
 139 #endif
 140                 } else {
 141 #ifdef SUPPORT_UTMP
 142                         if (utmpname(fname) == 0)
 143                                 warnx("Cannot set utmp file to `%s'",
 144                                     fname);
 145 #else
 146                         warnx("utmp support not compiled in");
 147 #endif
 148                 }
 149         }
 150 #ifdef SUPPORT_UTMPX
 151         if (what & 1) {
 152                 sfname = fname ? fname : _PATH_UTMPX;
 153                 if (stat(sfname, &st) == -1) {
 154                         warn("Cannot stat `%s'", sfname);
 155                         what &= ~1;
 156                 } else {
 157                         if (timespeccmp(&st.st_mtimespec, &utmpxtime, >))
 158                             utmpxtime = st.st_mtimespec;
 159                         else
 160                             what &= ~1;
 161                 }
 162         }
 163 #endif
 164 #ifdef SUPPORT_UTMP
 165         if (what & 2) {
 166                 sfname = fname ? fname : _PATH_UTMP;
 167                 if (stat(sfname, &st) == -1) {
 168                         warn("Cannot stat `%s'", sfname);
 169                         what &= ~2;
 170                 } else {
 171                         if (timespeccmp(&st.st_mtimespec, &utmptime, >))
 172                                 utmptime = st.st_mtimespec;
 173                         else
 174                                 what &= ~2;
 175                 }
 176         }
 177 #endif
 178         return what;
 179 }
 180 #endif
 181
 182 void
 183 endutentries(void)
 184 {
 185         struct utmpentry *ep;
 186
 187 #ifdef SUPPORT_UTMP
 188         timespecclear(&utmptime);
 189 #endif
 190 #ifdef SUPPORT_UTMPX
 191         timespecclear(&utmpxtime);
 192 #endif
 193         ep = ehead;
 194         while (ep) {
 195                 struct utmpentry *sep = ep;
 196                 ep = ep->next;
 197                 free(sep);
 198         }
 199         ehead = NULL;
 200         numutmp = 0;
 201 }
 202
 203 int
 204 getutentries(const char *fname, struct utmpentry **epp)
 205 {
 206 #ifdef SUPPORT_UTMPX
 207         struct utmpx *utx;
 208 #endif
 209 #ifdef SUPPORT_UTMP
 210         struct utmp *ut;
 211 #endif
 212 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
 213         struct utmpentry *ep;
 214         int what = setup(fname);
 215         struct utmpentry **nextp = &ehead;
 216         switch (what) {
 217         case 0:
 218                 /* No updates */
 219                 *epp = ehead;
 220                 return numutmp;
 221         default:
 222                 /* Need to re-scan */
 223                 ehead = NULL;
 224                 numutmp = 0;
 225         }
 226 #endif
 227
 228 #ifdef SUPPORT_UTMPX
 229         while ((what & 1) && (utx = getutxent()) != NULL) {
 230                 if (fname == NULL && ((1 << utx->ut_type) & etype) == 0) {
 231                         continue;
 232                 }
 233                 if ((ep = calloc(1, sizeof(struct utmpentry))) == NULL) {
 234                         warn(NULL);
 235                         return 0;
 236                 }
 237                 getentryx(ep, utx);
 238                 *nextp = ep;
 239                 nextp = &(ep->next);
 240         }
 241 #endif
 242
 243 #ifdef SUPPORT_UTMP
 244         if ((etype & (1 << USER_PROCESS)) != 0) {
 245                 while ((what & 2) && (ut = getutent()) != NULL) {
 246                         if (fname == NULL && (*ut->ut_name == '\0' ||
 247                             *ut->ut_line == '\0'))
 248                                 continue;
 249                         /* Don't process entries that we have utmpx for */
 250                         for (ep = ehead; ep != NULL; ep = ep->next) {
 251                                 if (strncmp(ep->line, ut->ut_line,
 252                                     sizeof(ut->ut_line)) == 0)
 253                                         break;
 254                         }
 255                         if (ep != NULL)
 256                                 continue;
 257                         if ((ep = calloc(1, sizeof(*ep))) == NULL) {
 258                                 warn(NULL);
 259                                 return 0;
 260                         }
 261                         getentry(ep, ut);
 262                         *nextp = ep;
 263                         nextp = &(ep->next);
 264                 }
 265         }
 266 #endif
 267         numutmp = 0;
 268 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
 269         if (ehead != NULL) {
 270                 struct utmpentry *from = ehead, *save;
 271
 272                 ehead = NULL;
 273                 while (from != NULL) {
 274                         for (nextp = &ehead;
 275                             (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
 276                             nextp = &(*nextp)->next)
 277                                 continue;
 278                         save = from;
 279                         from = from->next;
 280                         save->next = *nextp;
 281                         *nextp = save;
 282                         numutmp++;
 283                 }
 284         }
 285         *epp = ehead;
 286         return numutmp;
 287 #else
 288         *epp = NULL;
 289         return 0;
 290 #endif
 291 }
 292
 293 #ifdef SUPPORT_UTMP
 294 static void
 295 getentry(struct utmpentry *e, struct utmp *up)
 296 {
 297 #if 1
 298         COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
 299         COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
 300         COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
 301 #endif
 302
 303         /*
 304          * e has just been calloc'd. We don't need to clear it or
 305          * append null-terminators, because its length is strictly
 306          * greater than the source string. Use strncpy to _read_
 307          * up->ut_* because they may not be terminated. For this
 308          * reason we use the size of the _source_ as the length
 309          * argument.
 310          */
 311
 312         snprintf(e->name, sizeof(e->name), "%.*s",
 313                  (int)sizeof(up->ut_name), up->ut_name);
 314         snprintf(e->line, sizeof(e->line), "%.*s",
 315                  (int)sizeof(up->ut_line), up->ut_line);
 316         snprintf(e->host, sizeof(e->host), "%.*s",
 317                  (int)sizeof(up->ut_host), up->ut_host);
 318
 319         e->tv.tv_sec = up->ut_time;
 320         e->tv.tv_usec = 0;
 321         e->pid = 0;
 322         e->term = 0;
 323         e->exit = 0;
 324         e->sess = 0;
 325         e->type = USER_PROCESS;
 326         adjust_size(e);
 327 }
 328 #endif
 329
 330 #ifdef SUPPORT_UTMPX
 331 static void
 332 getentryx(struct utmpentry *e, struct utmpx *up)
 333 {
 334         COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
 335         COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
 336         COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
 337
 338         /*
 339          * e has just been calloc'd. We don't need to clear it or
 340          * append null-terminators, because its length is strictly
 341          * greater than the source string. Use strncpy to _read_
 342          * up->ut_* because they may not be terminated. For this
 343          * reason we use the size of the _source_ as the length
 344          * argument.
 345          */
 346         snprintf(e->name, sizeof(e->name), "%.*s",
 347                  (int)sizeof(up->ut_name), up->ut_name);
 348         snprintf(e->line, sizeof(e->line), "%.*s",
 349                  (int)sizeof(up->ut_line), up->ut_line);
 350         snprintf(e->host, sizeof(e->host), "%.*s",
 351                  (int)sizeof(up->ut_host), up->ut_host);
 352
 353         e->tv = up->ut_tv;
 354         e->pid = up->ut_pid;
 355         e->term = up->ut_exit.e_termination;
 356         e->exit = up->ut_exit.e_exit;
 357         e->sess = up->ut_session;
 358         e->type = up->ut_type;
 359         adjust_size(e);
 360 }
 361 #endif