last.c

sysvinit--linux系统下的init

		if (len >= sizeof(domain)) len = sizeof(domain) - 1;
		domain[0] = 0;
		strncat(domain, p->ut_host, len);
	}

	if (showhost) {
#if CHOP_DOMAIN
		/*
		 *	See if this is in our domain.
		 */
		if (!usedns && (s = strchr(p->ut_host, '.')) != NULL &&
		     strcmp(s + 1, domainname) == 0) *s = 0;
#endif
		if (!altlist) {
			snprintf(final, sizeof(final),
				"%-8.8s %-12.12s %-16.16s "
				"%-16.16s %-7.7s %-12.12s\n",
				p->ut_name, utline,
				domain, logintime, logouttime, length);
		} else {
			snprintf(final, sizeof(final), 
				"%-8.8s %-12.12s %-16.16s %-7.7s %-12.12s %s\n",
				p->ut_name, utline,
				logintime, logouttime, length, domain);
		}
	} else
		snprintf(final, sizeof(final),
			"%-8.8s %-12.12s %-16.16s %-7.7s %-12.12s\n",
			p->ut_name, utline,
			logintime, logouttime, length);

	/*
	 *	Print out "final" string safely.
	 */
	for (s = final; *s; s++) {
		if (*s == '\n' || (*s >= 32 && (unsigned char)*s <= 126))
			putchar(*s);
		else
			putchar('*');
	}

	recsdone++;
	if (maxrecs && recsdone >= maxrecs)
		return 1;

	return 0;
}


/*
 *	show usage
 */
void usage(char *s)
{
	fprintf(stderr, "Usage: %s [-num | -n num] [-f file] "
			"[-t YYYYMMDDHHMMSS] "
			"[-R] [-x] [-o] [username..] [tty..]\n", s);
	exit(1);
}

time_t parsetm(char *ts)
{
	struct tm	u = {0}, origu;
	time_t		tm;

	if (sscanf(ts, "%4d%2d%2d%2d%2d%2d", &u.tm_year,
	    &u.tm_mon, &u.tm_mday, &u.tm_hour, &u.tm_min,
	    &u.tm_sec) != 6)
		return (time_t)-1;

	u.tm_year -= 1900;
	u.tm_mon -= 1;
	u.tm_isdst = -1;

	origu = u;

	if ((tm = mktime(&u)) == (time_t)-1)
		return tm;

	/*
	 *	Unfortunately mktime() is much more forgiving than
	 *	it should be.  For example, it'll gladly accept
	 *	"30" as a valid month number.  This behavior is by
	 *	design, but we don't like it, so we want to detect
	 *	it and complain.
	 */
	if (u.tm_year != origu.tm_year ||
	    u.tm_mon != origu.tm_mon ||
	    u.tm_mday != origu.tm_mday ||
	    u.tm_hour != origu.tm_hour ||
	    u.tm_min != origu.tm_min ||
	    u.tm_sec != origu.tm_sec)
		return (time_t)-1;

	return tm;
}

int main(int argc, char **argv)
{
  FILE *fp;		/* Filepointer of wtmp file */

  struct utmp ut;	/* Current utmp entry */
  struct utmp oldut;	/* Old utmp entry to check for duplicates */
  struct utmplist *p;	/* Pointer into utmplist */
  struct utmplist *next;/* Pointer into utmplist */

  time_t lastboot = 0;  /* Last boottime */
  time_t lastrch = 0;	/* Last run level change */
  time_t lastdown;	/* Last downtime */
  time_t begintime;	/* When wtmp begins */
  int whydown = 0;	/* Why we went down: crash or shutdown */

  int c, x;		/* Scratch */
  struct stat st;	/* To stat the [uw]tmp file */
  int quit = 0;		/* Flag */
  int down = 0;		/* Down flag */
  int lastb = 0;	/* Is this 'lastb' ? */
  int extended = 0;	/* Lots of info. */
  char *altufile = NULL;/* Alternate wtmp */

  time_t until = 0;	/* at what time to stop parsing the file */

  progname = mybasename(argv[0]);

  /* Process the arguments. */
  while((c = getopt(argc, argv, "f:n:Rxadiot:0123456789")) != EOF)
    switch(c) {
	case 'R':
		showhost = 0;
		break;
	case 'x':
		extended = 1;
		break;
	case 'n':
		maxrecs = atoi(optarg);
		break;
	case 'o':
		oldfmt = 1;
		break;
	case 'f':
		if((altufile = malloc(strlen(optarg)+1)) == NULL) {
			fprintf(stderr, "%s: out of memory\n",
				progname);
			exit(1);
		}
		strcpy(altufile, optarg);
		break;
	case 'd':
		usedns++;
		break;
	case 'i':
		useip++;
		break;
	case 'a':
		altlist++;
		break;
	case 't':
		if ((until = parsetm(optarg)) == (time_t)-1) {
			fprintf(stderr, "%s: Invalid time value \"%s\"\n",
				progname, optarg);
			usage(progname);
		}
		break;
	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':
		maxrecs = 10*maxrecs + c - '0';
		break;
	default:
		usage(progname);
		break;
    }
  if (optind < argc) show = argv + optind;

  /*
   *	Which file do we want to read?
   */
  if (strcmp(progname, "lastb") == 0) {
	ufile = BTMP_FILE;
	lastb = 1;
  } else
	ufile = WTMP_FILE;
  if (altufile)
	ufile = altufile;
  time(&lastdown);
  lastrch = lastdown;

  /*
   *	Fill in 'lastdate'
   */
  lastdate = lastdown;

#if CHOP_DOMAIN
  /*
   *	Find out domainname.
   *
   *	This doesn't work on modern systems, where only a DNS
   *	lookup of the result from hostname() will get you the domainname.
   *	Remember that domainname() is the NIS domainname, not DNS.
   *	So basically this whole piece of code is bullshit.
   */
  hostname[0] = 0;
  (void) gethostname(hostname, sizeof(hostname));
  if ((domainname = strchr(hostname, '.')) != NULL) domainname++;
  if (domainname == NULL || domainname[0] == 0) {
	hostname[0] = 0;
	(void) getdomainname(hostname, sizeof(hostname));
	hostname[sizeof(hostname) - 1] = 0;
	domainname = hostname;
	if (strcmp(domainname, "(none)") == 0 || domainname[0] == 0)
		domainname = NULL;
  }
#endif

  /*
   *	Install signal handlers
   */
  signal(SIGINT, int_handler);
  signal(SIGQUIT, quit_handler);

  /*
   *	Open the utmp file
   */
  if ((fp = fopen(ufile, "r")) == NULL) {
	x = errno;
	fprintf(stderr, "%s: %s: %s\n", progname, ufile, strerror(errno));
	if (altufile == NULL && x == ENOENT)
		fprintf(stderr, "Perhaps this file was removed by the "
			"operator to prevent logging %s info.\n", progname);
	exit(1);
  }

  /*
   *	Optimize the buffer size.
   */
  setvbuf(fp, NULL, _IOFBF, UCHUNKSIZE);

  /*
   *	Read first structure to capture the time field
   */
  if (uread(fp, &ut, NULL) == 1)
	begintime = ut.ut_time;
  else {
  	fstat(fileno(fp), &st);
	begintime = st.st_ctime;
	quit = 1;
  }

  /*
   *	Go to end of file minus one structure
   *	and/or initialize utmp reading code.
   */
  uread(fp, NULL, NULL);

  /*
   *	Read struct after struct backwards from the file.
   */
  while(!quit) {

	if (uread(fp, &ut, &quit) != 1)
		break;

	if (until && until < ut.ut_time)
		continue;

	if (memcmp(&ut, &oldut, sizeof(struct utmp)) == 0) continue;
	memcpy(&oldut, &ut, sizeof(struct utmp));
	lastdate = ut.ut_time;

  	if (lastb) {
  		quit = list(&ut, ut.ut_time, R_NORMAL);
  		continue;
  	}

	/*
	 *	Set ut_type to the correct type.
	 */
	if (strncmp(ut.ut_line, "~", 1) == 0) {
		if (strncmp(ut.ut_user, "shutdown", 8) == 0)
			ut.ut_type = SHUTDOWN_TIME;
		else if (strncmp(ut.ut_user, "reboot", 6) == 0)
			ut.ut_type = BOOT_TIME;
		else if (strncmp(ut.ut_user, "runlevel", 7) == 0)
			ut.ut_type = RUN_LVL;
	}
#if 1 /*def COMPAT*/
	/*
	 *	For stupid old applications that don't fill in
	 *	ut_type correctly.
	 */
	else {
		if (ut.ut_type != DEAD_PROCESS &&
		    ut.ut_name[0] && ut.ut_line[0] &&
		    strcmp(ut.ut_name, "LOGIN") != 0)
			ut.ut_type = USER_PROCESS;
		/*
		 *	Even worse, applications that write ghost
		 *	entries: ut_type set to USER_PROCESS but
		 *	empty ut_name...
		 */
		if (ut.ut_name[0] == 0)
			ut.ut_type = DEAD_PROCESS;

		/*
		 *	Clock changes.
		 */
		if (strcmp(ut.ut_name, "date") == 0) {
			if (ut.ut_line[0] == '|') ut.ut_type = OLD_TIME;
			if (ut.ut_line[0] == '{') ut.ut_type = NEW_TIME;
		}
	}
#endif

	switch (ut.ut_type) {
		case SHUTDOWN_TIME:
			if (extended) {
				strcpy(ut.ut_line, "system down");
				quit = list(&ut, lastdown, R_NORMAL);
			}
			lastdown = lastrch = ut.ut_time;
			down = 1;
			break;
		case OLD_TIME:
		case NEW_TIME:
			if (extended) {
				strcpy(ut.ut_line,
				ut.ut_type == NEW_TIME ? "new time" :
					"old time");
				quit = list(&ut, lastdown, R_TIMECHANGE);
			}
			break;
		case BOOT_TIME:
			strcpy(ut.ut_line, "system boot");
			quit = list(&ut, lastdown, R_REBOOT);
			down = 1;
			break;
		case RUN_LVL:
			x = ut.ut_pid & 255;
			if (extended) {
				sprintf(ut.ut_line, "(to lvl %c)", x);
				quit = list(&ut, lastrch, R_NORMAL);
			}
			if (x == '0' || x == '6') {
				lastdown = ut.ut_time;
				down = 1;
				ut.ut_type = SHUTDOWN_TIME;
			}
			lastrch = ut.ut_time;
			break;

		case USER_PROCESS:
			/*
			 *	This was a login - show the first matching
			 *	logout record and delete all records with
			 *	the same ut_line.
			 */
			c = 0;
			for (p = utmplist; p; p = next) {
				next = p->next;
				if (strncmp(p->ut.ut_line, ut.ut_line,
				    UT_LINESIZE) == 0) {
					/* Show it */
					if (c == 0) {
						quit = list(&ut, p->ut.ut_time,
							R_NORMAL);
						c = 1;
					}
					if (p->next) p->next->prev = p->prev;
					if (p->prev)
						p->prev->next = p->next;
					else
						utmplist = p->next;
					free(p);
				}
			}
			/*
			 *	Not found? Then crashed, down, still
			 *	logged in, or missing logout record.
			 */
			if (c == 0) {
				if (lastboot == 0) {
					c = R_NOW;
					/* Is process still alive? */
					if (ut.ut_pid > 0 &&
					    kill(ut.ut_pid, 0) != 0 &&
					    errno == ESRCH)
						c = R_PHANTOM;
				} else
					c = whydown;
				quit = list(&ut, lastboot, c);
			}
			/* FALLTHRU */

		case DEAD_PROCESS:
			/*
			 *	Just store the data if it is
			 *	interesting enough.
			 */
			if (ut.ut_line[0] == 0)
				break;
			if ((p = malloc(sizeof(struct utmplist))) == NULL) {
				fprintf(stderr, "%s: out of memory\n",
					progname);
				exit(1);
			}
			memcpy(&p->ut, &ut, sizeof(struct utmp));
			p->next  = utmplist;
			p->prev  = NULL;
			if (utmplist) utmplist->prev = p;
			utmplist = p;
			break;

	}
	/*
	 *	If we saw a shutdown/reboot record we can remove
	 *	the entire current utmplist.
	 */
	if (down) {
		lastboot = ut.ut_time;
		whydown = (ut.ut_type == SHUTDOWN_TIME) ? R_DOWN : R_CRASH;
		for (p = utmplist; p; p = next) {
			next = p->next;
			free(p);
		}
		utmplist = NULL;
		down = 0;
	}
  }
  printf("\n%s begins %s", mybasename(ufile), ctime(&begintime));

  fclose(fp);

  /*
   *	Should we free memory here? Nah. This is not NT :)
   */
  return 0;
}