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
  34 #include <sys/stat.h>
  35
  36 #include <time.h>
  37 #include <string.h>
  38 #include <err.h>
  39 #include <stdlib.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 /* Fail the compile if x is not true, by constructing an illegal type. */
  79 #define COMPILE_ASSERT(x) /*LINTED null effect */ \
  80         ((void)sizeof(struct { unsigned : ((x) ? 1 : -1); }))
  81
  82
  83 #ifdef SUPPORT_UTMP
  84 static void getentry(struct utmpentry *, struct utmp *);
  85 static struct timespec utmptime = {0, 0};
  86 #endif
  87 #ifdef SUPPORT_UTMPX
  88 static void getentryx(struct utmpentry *, struct utmpx *);
  89 static struct timespec utmpxtime = {0, 0};
  90 #endif
  91 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
  92 static int setup(const char *);
  93 static void adjust_size(struct utmpentry *e);
  94 #endif
  95
  96 int maxname = 8, maxline = 8, maxhost = 16;
  97 int etype = 1 << USER_PROCESS;
  98 static int numutmp = 0;
  99 static struct utmpentry *ehead;
 100
 101 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
 102 static void
 103 adjust_size(struct utmpentry *e)
 104 {
 105         int max;
 106
 107         if ((max = strlen(e->name)) > maxname)
 108                 maxname = max;
 109         if ((max = strlen(e->line)) > maxline)
 110                 maxline = max;
 111         if ((max = strlen(e->host)) > maxhost)
 112                 maxhost = max;
 113 }
 114
 115 static int
 116 setup(const char *fname)
 117 {
 118         int what = 3;
 119         struct stat st;
 120         const char *sfname;
 121
 122         if (fname == NULL) {
 123 #ifdef SUPPORT_UTMPX
 124                 setutxent();
 125 #endif
 126 #ifdef SUPPORT_UTMP
 127                 setutent();
 128 #endif
 129         } else {
 130                 size_t len = strlen(fname);
 131                 if (len == 0)
 132                         errx(1, "Filename cannot be 0 length.");
 133                 what = fname[len - 1] == 'x' ? 1 : 2;
 134                 if (what == 1) {
 135 #ifdef SUPPORT_UTMPX
 136                         if (utmpxname(fname) == 0)
 137                                 warnx("Cannot set utmpx file to `%s'",
 138                                     fname);
 139 #else
 140                         warnx("utmpx support not compiled in");
 141 #endif
 142                 } else {
 143 #ifdef SUPPORT_UTMP
 144                         if (utmpname(fname) == 0)
 145                                 warnx("Cannot set utmp file to `%s'",
 146                                     fname);
 147 #else
 148                         warnx("utmp support not compiled in");
 149 #endif
 150                 }
 151         }
 152 #ifdef SUPPORT_UTMPX
 153         if (what & 1) {
 154                 sfname = fname ? fname : _PATH_UTMPX;
 155                 if (stat(sfname, &st) == -1) {
 156                         warn("Cannot stat `%s'", sfname);
 157                         what &= ~1;
 158                 } else {
 159                         if (timespeccmp(&st.st_mtimespec, &utmpxtime, >))
 160                             utmpxtime = st.st_mtimespec;
 161                         else
 162                             what &= ~1;
 163                 }
 164         }
 165 #endif
 166 #ifdef SUPPORT_UTMP
 167         if (what & 2) {
 168                 sfname = fname ? fname : _PATH_UTMP;
 169                 if (stat(sfname, &st) == -1) {
 170                         warn("Cannot stat `%s'", sfname);
 171                         what &= ~2;
 172                 } else {
 173                         if (timespeccmp(&st.st_mtimespec, &utmptime, >))
 174                                 utmptime = st.st_mtimespec;
 175                         else
 176                                 what &= ~2;
 177                 }
 178         }
 179 #endif
 180         return what;
 181 }
 182 #endif
 183
 184 void
 185 endutentries(void)
 186 {
 187         struct utmpentry *ep;
 188
 189 #ifdef SUPPORT_UTMP
 190         timespecclear(&utmptime);
 191 #endif
 192 #ifdef SUPPORT_UTMPX
 193         timespecclear(&utmpxtime);
 194 #endif
 195         ep = ehead;
 196         while (ep) {
 197                 struct utmpentry *sep = ep;
 198                 ep = ep->next;
 199                 free(sep);
 200         }
 201         ehead = NULL;
 202         numutmp = 0;
 203 }
 204
 205 int
 206 getutentries(const char *fname, struct utmpentry **epp)
 207 {
 208 #ifdef SUPPORT_UTMPX
 209         struct utmpx *utx;
 210 #endif
 211 #ifdef SUPPORT_UTMP
 212         struct utmp *ut;
 213 #endif
 214 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
 215         struct utmpentry *ep;
 216         int what = setup(fname);
 217         struct utmpentry **nextp = &ehead;
 218         switch (what) {
 219         case 0:
 220                 /* No updates */
 221                 *epp = ehead;
 222                 return numutmp;
 223         default:
 224                 /* Need to re-scan */
 225                 ehead = NULL;
 226                 numutmp = 0;
 227         }
 228 #endif
 229
 230 #ifdef SUPPORT_UTMPX
 231         while ((what & 1) && (utx = getutxent()) != NULL) {
 232                 if (fname == NULL && ((1 << utx->ut_type) & etype) == 0) {
 233                         continue;
 234                 }
 235                 if ((ep = calloc(1, sizeof(struct utmpentry))) == NULL) {
 236                         warn(NULL);
 237                         return 0;
 238                 }
 239                 getentryx(ep, utx);
 240                 *nextp = ep;
 241                 nextp = &(ep->next);
 242         }
 243 #endif
 244
 245 #ifdef SUPPORT_UTMP
 246         if ((etype & (1 << USER_PROCESS)) != 0) {
 247                 while ((what & 2) && (ut = getutent()) != NULL) {
 248                         if (fname == NULL && (*ut->ut_name == '\0' ||
 249                             *ut->ut_line == '\0'))
 250                                 continue;
 251                         /* Don't process entries that we have utmpx for */
 252                         for (ep = ehead; ep != NULL; ep = ep->next) {
 253                                 if (strncmp(ep->line, ut->ut_line,
 254                                     sizeof(ut->ut_line)) == 0)
 255                                         break;
 256                         }
 257                         if (ep != NULL)
 258                                 continue;
 259                         if ((ep = calloc(1, sizeof(*ep))) == NULL) {
 260                                 warn(NULL);
 261                                 return 0;
 262                         }
 263                         getentry(ep, ut);
 264                         *nextp = ep;
 265                         nextp = &(ep->next);
 266                 }
 267         }
 268 #endif
 269         numutmp = 0;
 270 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
 271         if (ehead != NULL) {
 272                 struct utmpentry *from = ehead, *save;
 273
 274                 ehead = NULL;
 275                 while (from != NULL) {
 276                         for (nextp = &ehead;
 277                             (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
 278                             nextp = &(*nextp)->next)
 279                                 continue;
 280                         save = from;
 281                         from = from->next;
 282                         save->next = *nextp;
 283                         *nextp = save;
 284                         numutmp++;
 285                 }
 286         }
 287         *epp = ehead;
 288         return numutmp;
 289 #else
 290         *epp = NULL;
 291         return 0;
 292 #endif
 293 }
 294
 295 #ifdef SUPPORT_UTMP
 296 static void
 297 getentry(struct utmpentry *e, struct utmp *up)
 298 {
 299 #if 1
 300         COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
 301         COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
 302         COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
 303 #endif
 304
 305         /*
 306          * e has just been calloc'd. We don't need to clear it or
 307          * append null-terminators, because its length is strictly
 308          * greater than the source string. Use strncpy to _read_
 309          * up->ut_* because they may not be terminated. For this
 310          * reason we use the size of the _source_ as the length
 311          * argument.
 312          */
 313         (void)strncpy(e->name, up->ut_name, sizeof(up->ut_name));
 314         (void)strncpy(e->line, up->ut_line, sizeof(up->ut_line));
 315         (void)strncpy(e->host, up->ut_host, sizeof(up->ut_host));
 316
 317         e->tv.tv_sec = up->ut_time;
 318         e->tv.tv_usec = 0;
 319         e->pid = 0;
 320         e->term = 0;
 321         e->exit = 0;
 322         e->sess = 0;
 323         e->type = USER_PROCESS;
 324         adjust_size(e);
 325 }
 326 #endif
 327
 328 #ifdef SUPPORT_UTMPX
 329 static void
 330 getentryx(struct utmpentry *e, struct utmpx *up)
 331 {
 332 #if 1
 333         COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
 334         COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
 335         COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
 336 #endif
 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         (void)strncpy(e->name, up->ut_name, sizeof(up->ut_name));
 347         (void)strncpy(e->line, up->ut_line, sizeof(up->ut_line));
 348         (void)strncpy(e->host, up->ut_host, sizeof(up->ut_host));
 349
 350         e->tv = up->ut_tv;
 351         e->pid = up->ut_pid;
 352         e->term = up->ut_exit.e_termination;
 353         e->exit = up->ut_exit.e_exit;
 354         e->sess = up->ut_session;
 355         e->type = up->ut_type;
 356         adjust_size(e);
 357 }
 358 #endif