void
receiver_process(void)
{
struct sockaddr_in from;
struct stat st;
cap_rights_t rights;
char path[64];
int dirfd;
struct whod wd;
socklen_t len;
int cc, whod;
time_t t;
len = sizeof(from);
dirfd = open(".", O_RDONLY | O_DIRECTORY);
if (dirfd < 0) {
syslog(LOG_WARNING, "%s: %m", _PATH_RWHODIR);
exit(1);
}
cap_rights_init(&rights, CAP_CREATE, CAP_FSTAT, CAP_FTRUNCATE,
CAP_LOOKUP, CAP_SEEK, CAP_WRITE);
if (caph_rights_limit(dirfd, &rights) < 0) {
syslog(LOG_WARNING, "cap_rights_limit: %m");
exit(1);
}
if (caph_enter() < 0) {
syslog(LOG_ERR, "cap_enter: %m");
exit(1);
}
for (;;) {
cc = recvfrom(s, &wd, sizeof(wd), 0, (struct sockaddr *)&from,
&len);
if (cc <= 0) {
if (cc < 0 && errno != EINTR)
syslog(LOG_WARNING, "recv: %m");
continue;
}
if (from.sin_port != sp->s_port && !insecure_mode) {
syslog(LOG_WARNING, "%d: bad source port from %s",
ntohs(from.sin_port), inet_ntoa(from.sin_addr));
continue;
}
if (cc < WHDRSIZE) {
syslog(LOG_WARNING, "short packet from %s",
inet_ntoa(from.sin_addr));
continue;
}
if (wd.wd_vers != WHODVERSION)
continue;
if (wd.wd_type != WHODTYPE_STATUS)
continue;
if (!verify(wd.wd_hostname, sizeof(wd.wd_hostname))) {
syslog(LOG_WARNING, "malformed host name from %s",
inet_ntoa(from.sin_addr));
continue;
}
(void) snprintf(path, sizeof(path), "whod.%s", wd.wd_hostname);
/*
* Rather than truncating and growing the file each time,
* use ftruncate if size is less than previous size.
*/
whod = openat(dirfd, path, O_WRONLY | O_CREAT, 0644);
if (whod < 0) {
syslog(LOG_WARNING, "%s: %m", path);
continue;
}
cap_rights_init(&rights, CAP_FSTAT, CAP_FTRUNCATE, CAP_WRITE);
if (caph_rights_limit(whod, &rights) < 0) {
syslog(LOG_WARNING, "cap_rights_limit: %m");
exit(1);
}
#if ENDIAN != BIG_ENDIAN
{
struct whoent *we;
int i, n;
n = (cc - WHDRSIZE) / sizeof(struct whoent);
/* undo header byte swapping before writing to file */
wd.wd_sendtime = ntohl(wd.wd_sendtime);
for (i = 0; i < 3; i++)
wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
wd.wd_boottime = ntohl(wd.wd_boottime);
we = wd.wd_we;
for (i = 0; i < n; i++) {
we->we_idle = ntohl(we->we_idle);
we->we_utmp.out_time =
ntohl(we->we_utmp.out_time);
we++;
}
}
#endif
(void) time(&t);
wd.wd_recvtime = _time_to_int(t);
(void) write(whod, (char *)&wd, cc);
if (fstat(whod, &st) < 0 || st.st_size > cc)
ftruncate(whod, cc);
(void) close(whod);
}
(void) close(dirfd);
}
int
main(int argc, char *argv[])
{
struct sockaddr_in from;
struct stat st;
char path[64];
int on = 1;
char *cp;
struct sockaddr_in soin;
uid_t unpriv_uid;
gid_t unpriv_gid;
if (getuid())
errx(1, "not super user");
run_as(&unpriv_uid, &unpriv_gid);
argv++; argc--;
while (argc > 0 && *argv[0] == '-') {
if (strcmp(*argv, "-m") == 0) {
if (argc > 1 && isdigit(*(argv + 1)[0])) {
argv++, argc--;
multicast_mode = SCOPED_MULTICAST;
multicast_scope = atoi(*argv);
if (multicast_scope > MAX_MULTICAST_SCOPE)
errx(1, "ttl must not exceed %u",
MAX_MULTICAST_SCOPE);
}
else multicast_mode = PER_INTERFACE_MULTICAST;
}
else if (strcmp(*argv, "-i") == 0)
insecure_mode = 1;
else if (strcmp(*argv, "-l") == 0)
quiet_mode = 1;
else if (strcmp(*argv, "-p") == 0)
iff_flag = 0;
else
usage();
argv++, argc--;
}
if (argc > 0)
usage();
#ifndef DEBUG
daemon(1, 0);
#endif
(void) signal(SIGHUP, getboottime);
openlog("rwhod", LOG_PID, LOG_DAEMON);
sp = getservbyname("who", "udp");
if (sp == NULL) {
syslog(LOG_ERR, "who/udp: unknown service");
exit(1);
}
if (chdir(_PATH_RWHODIR) < 0) {
syslog(LOG_ERR, "%s: %m", _PATH_RWHODIR);
exit(1);
}
/*
* Establish host name as returned by system.
*/
if (gethostname(myname, sizeof(myname) - 1) < 0) {
syslog(LOG_ERR, "gethostname: %m");
exit(1);
}
if ((cp = index(myname, '.')) != NULL)
*cp = '\0';
strncpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname) - 1);
mywd.wd_hostname[sizeof(mywd.wd_hostname) - 1] = '\0';
#ifdef __APPLE__
utmpf = open(_PATH_UTMPX, O_RDONLY|O_CREAT, 0644);
#else
utmpf = open(_PATH_UTMP, O_RDONLY|O_CREAT, 0644);
#endif
if (utmpf < 0) {
#ifdef __APPLE__
syslog(LOG_ERR, "%s: %m", _PATH_UTMPX);
#else
syslog(LOG_ERR, "%s: %m", _PATH_UTMP);
#endif
exit(1);
}
getboottime(0);
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
syslog(LOG_ERR, "socket: %m");
exit(1);
}
if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) {
syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m");
exit(1);
}
memset(&soin, 0, sizeof(soin));
soin.sin_len = sizeof(soin);
soin.sin_family = AF_INET;
soin.sin_port = sp->s_port;
if (bind(s, (struct sockaddr *)&soin, sizeof(soin)) < 0) {
syslog(LOG_ERR, "bind: %m");
exit(1);
}
setgid(unpriv_gid);
setgroups(1, &unpriv_gid); /* XXX BOGUS groups[0] = egid */
setuid(unpriv_uid);
if (!configure(s))
exit(1);
if (!quiet_mode) {
signal(SIGALRM, onalrm);
onalrm(0);
}
for (;;) {
struct whod wd;
socklen_t len = sizeof(from);
int cc, whod;
time_t t;
cc = recvfrom(s, (char *)&wd, sizeof(struct whod), 0,
(struct sockaddr *)&from, &len);
if (cc <= 0) {
if (cc < 0 && errno != EINTR)
syslog(LOG_WARNING, "recv: %m");
continue;
}
if (from.sin_port != sp->s_port && !insecure_mode) {
syslog(LOG_WARNING, "%d: bad source port from %s",
ntohs(from.sin_port), inet_ntoa(from.sin_addr));
continue;
}
if (cc < WHDRSIZE) {
syslog(LOG_WARNING, "short packet from %s",
inet_ntoa(from.sin_addr));
continue;
}
if (wd.wd_vers != WHODVERSION)
continue;
if (wd.wd_type != WHODTYPE_STATUS)
continue;
if (!verify(wd.wd_hostname, sizeof wd.wd_hostname)) {
syslog(LOG_WARNING, "malformed host name from %s",
inet_ntoa(from.sin_addr));
continue;
}
(void) snprintf(path, sizeof path, "whod.%s", wd.wd_hostname);
/*
* Rather than truncating and growing the file each time,
* use ftruncate if size is less than previous size.
*/
whod = open(path, O_WRONLY | O_CREAT, 0644);
if (whod < 0) {
syslog(LOG_WARNING, "%s: %m", path);
continue;
}
#if ENDIAN != BIG_ENDIAN
{
int i, n = (cc - WHDRSIZE)/sizeof(struct whoent);
struct whoent *we;
/* undo header byte swapping before writing to file */
wd.wd_sendtime = ntohl(wd.wd_sendtime);
for (i = 0; i < 3; i++)
wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
wd.wd_boottime = ntohl(wd.wd_boottime);
we = wd.wd_we;
for (i = 0; i < n; i++) {
we->we_idle = ntohl(we->we_idle);
we->we_utmp.out_time =
ntohl(we->we_utmp.out_time);
we++;
}
}
#endif
(void) time(&t);
wd.wd_recvtime = _time_to_int(t);
(void) write(whod, (char *)&wd, cc);
if (fstat(whod, &st) < 0 || st.st_size > cc)
ftruncate(whod, cc);
(void) close(whod);
}
}
