/*
* utmpdump
*
* Simple program to dump UTMP and WTMP files in raw format, so they can be
* examined.
*
* Based on utmpdump dump from sysvinit suite.
*
* Copyright (C) 1991-2000 Miquel van Smoorenburg <miquels@cistron.nl>
*
* Copyright (C) 1998 Danek Duvall <duvall@alumni.princeton.edu>
* Copyright (C) 2012 Karel Zak <kzak@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <utmp.h>
#include <time.h>
#include <ctype.h>
#include <getopt.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#ifdef HAVE_INOTIFY_INIT
#include <sys/inotify.h>
#endif
#include "c.h"
#include "nls.h"
#include "xalloc.h"
#include "closestream.h"
static char *timetostr(const time_t time)
{
static char s[29]; /* [Sun Sep 01 00:00:00 1998 PST] */
struct tm *tmp;
if (time != 0 && (tmp = localtime(&time)))
strftime(s, 29, "%a %b %d %T %Y %Z", tmp);
else
s[0] = '\0';
return s;
}
static time_t strtotime(const char *s_time)
{
struct tm tm;
memset(&tm, '\0', sizeof(struct tm));
if (s_time[0] == ' ' || s_time[0] == '\0')
return (time_t)0;
strptime(s_time, "%a %b %d %T %Y", &tm);
/* Cheesy way of checking for DST */
if (s_time[26] == 'D')
tm.tm_isdst = 1;
return mktime(&tm);
}
#define cleanse(x) xcleanse(x, sizeof(x))
static void xcleanse(char *s, int len)
{
for ( ; *s && len-- > 0; s++)
if (!isprint(*s) || *s == '[' || *s == ']')
*s = '?';
}
static void print_utline(struct utmp ut, FILE *out)
{
const char *addr_string, *time_string;
char buffer[INET6_ADDRSTRLEN];
if (ut.ut_addr_v6[1] || ut.ut_addr_v6[2] || ut.ut_addr_v6[3])
addr_string = inet_ntop(AF_INET6, &(ut.ut_addr_v6), buffer, sizeof(buffer));
else
addr_string = inet_ntop(AF_INET, &(ut.ut_addr_v6), buffer, sizeof(buffer));
#if defined(_HAVE_UT_TV)
time_string = timetostr(ut.ut_tv.tv_sec);
#else
time_string = timetostr((time_t)ut.ut_time); /* ut_time is not always a time_t */
#endif
cleanse(ut.ut_id);
cleanse(ut.ut_user);
cleanse(ut.ut_line);
cleanse(ut.ut_host);
/* pid id user line host addr time */
fprintf(out, "[%d] [%05d] [%-4.4s] [%-*.*s] [%-*.*s] [%-*.*s] [%-15s] [%-28.28s]\n",
ut.ut_type, ut.ut_pid, ut.ut_id, 8, UT_NAMESIZE, ut.ut_user,
12, UT_LINESIZE, ut.ut_line, 20, UT_HOSTSIZE, ut.ut_host,
addr_string, time_string);
}
#ifdef HAVE_INOTIFY_INIT
#define EVENTS (IN_MODIFY|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT)
#define NEVENTS 4
static void roll_file(const char *filename, off_t *size, FILE *out)
{
FILE *in;
struct stat st;
struct utmp ut;
off_t pos;
if (!(in = fopen(filename, "r")))
err(EXIT_FAILURE, _("cannot open %s"), filename);
if (fstat(fileno(in), &st) == -1)
err(EXIT_FAILURE, _("%s: stat failed"), filename);
if (st.st_size == *size)
goto done;
if (fseek(in, *size, SEEK_SET) != (off_t) -1) {
while (fread(&ut, sizeof(ut), 1, in) == 1)
print_utline(ut, out);
}
pos = ftello(in);
/* If we've successfully read something, use the file position, this
* avoids data duplication. If we read nothing or hit an error,
* reset to the reported size, this handles truncated files.
*/
*size = (pos != -1 && pos != *size) ? pos : st.st_size;
done:
fclose(in);
}
static int follow_by_inotify(FILE *in, const char *filename, FILE *out)
{
char buf[NEVENTS * sizeof(struct inotify_event)];
int fd, wd, event;
ssize_t length;
off_t size;
fd = inotify_init();
if (fd == -1)
return -1; /* probably reached any limit ... */
size = ftello(in);
fclose(in);
wd = inotify_add_watch(fd, filename, EVENTS);
if (wd == -1)
err(EXIT_FAILURE, _("%s: cannot add inotify watch."), filename);
while (wd >= 0) {
errno = 0;
length = read(fd, buf, sizeof(buf));
if (length < 0 && (errno == EINTR || errno == EAGAIN))
continue;
if (length < 0)
err(EXIT_FAILURE, _("%s: cannot read inotify events"),
filename);
for (event = 0; event < length;) {
struct inotify_event *ev =
(struct inotify_event *) &buf[event];
if (ev->mask & IN_MODIFY)
roll_file(filename, &size, out);
else {
close(wd);
wd = -1;
break;
}
event += sizeof(struct inotify_event) + ev->len;
}
}
close(fd);
return 0;
}
#endif /* HAVE_INOTIFY_INIT */
static FILE *dump(FILE *in, const char *filename, int follow, FILE *out)
{
struct utmp ut;
if (follow)
ignore_result( fseek(in, -10 * sizeof(ut), SEEK_END) );
while (fread(&ut, sizeof(ut), 1, in) == 1)
print_utline(ut, out);
if (!follow)
return in;
#ifdef HAVE_INOTIFY_INIT
if (follow_by_inotify(in, filename, out) == 0)
return NULL; /* file already closed */
else
#endif
/* fallback for systems without inotify or with non-free
* inotify instances */
for (;;) {
while (fread(&ut, sizeof(ut), 1, in) == 1)
print_utline(ut, out);
sleep(1);
}
return in;
}
/* This function won't work properly if there's a ']' or a ' ' in the real
* token. Thankfully, this should never happen. */
static int gettok(char *line, char *dest, int size, int eatspace)
{
int bpos, epos, eaten;
bpos = strchr(line, '[') - line;
if (bpos < 0)
errx(EXIT_FAILURE, _("Extraneous newline in file. Exiting."));
line += 1 + bpos;
epos = strchr(line, ']') - line;
if (epos < 0)
errx(EXIT_FAILURE, _("Extraneous newline in file. Exiting."));
line[epos] = '\0';
eaten = bpos + epos + 1;
if (eatspace) {
char *t;
if ((t = strchr(line, ' ')))
*t = 0;
}
strncpy(dest, line, size);
return eaten + 1;
}
static void undump(FILE *in, FILE *out)
{
struct utmp ut;
char s_addr[INET6_ADDRSTRLEN + 1], s_time[29], *linestart, *line;
int count = 0;
linestart = xmalloc(1024 * sizeof(*linestart));
s_time[28] = 0;
while (fgets(linestart, 1023, in)) {
line = linestart;
memset(&ut, '\0', sizeof(ut));
sscanf(line, "[%hd] [%d] [%4c] ", &ut.ut_type, &ut.ut_pid, ut.ut_id);
line += 19;
line += gettok(line, ut.ut_user, sizeof(ut.ut_user), 1);
line += gettok(line, ut.ut_line, sizeof(ut.ut_line), 1);
line += gettok(line, ut.ut_host, sizeof(ut.ut_host), 1);
line += gettok(line, s_addr, sizeof(s_addr) - 1, 1);
gettok(line, s_time, sizeof(s_time) - 1, 0);
if (strchr(s_addr, '.'))
inet_pton(AF_INET, s_addr, &(ut.ut_addr_v6));
else
inet_pton(AF_INET6, s_addr, &(ut.ut_addr_v6));
#if defined(_HAVE_UT_TV)
ut.ut_tv.tv_sec = strtotime(s_time);
#else
ut.ut_time = strtotime(s_time);
#endif
ignore_result( fwrite(&ut, sizeof(ut), 1, out) );
++count;
}
free(linestart);
}
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] [filename]\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -f, --follow output appended data as the file grows\n"), out);
fputs(_(" -r, --reverse write back dumped data into utmp file\n"), out);
fputs(_(" -o, --output <file> write to file instead of standard output\n"), out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("utmpdump(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
int c;
FILE *in = NULL, *out = NULL;
int reverse = 0, follow = 0;
const char *filename = NULL;
static const struct option longopts[] = {
{ "follow", 0, 0, 'f' },
{ "reverse", 0, 0, 'r' },
{ "output", required_argument, 0, 'o' },
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
{ NULL, 0, 0, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv, "fro:hV", longopts, NULL)) != -1) {
switch (c) {
case 'r':
reverse = 1;
break;
case 'f':
follow = 1;
break;
case 'o':
out = fopen(optarg, "w");
if (!out)
err(EXIT_FAILURE, _("cannot open %s"),
optarg);
break;
case 'h':
usage(stdout);
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
default:
usage(stderr);
}
}
if (!out)
out = stdout;
if (optind < argc) {
filename = argv[optind];
in = fopen(filename, "r");
if (!in)
err(EXIT_FAILURE, _("cannot open %s"), filename);
} else {
if (follow)
errx(EXIT_FAILURE, _("following standard input is unsupported"));
filename = "/dev/stdin";
in = stdin;
}
if (reverse) {
fprintf(stderr, _("Utmp undump of %s\n"), filename);
undump(in, out);
} else {
fprintf(stderr, _("Utmp dump of %s\n"), filename);
in = dump(in, filename, follow, out);
}
if (out != stdout)
if (close_stream(out))
err(EXIT_FAILURE, _("write failed"));
if (in && in != stdin)
fclose(in);
return EXIT_SUCCESS;
}
