The whole sending functionality was implemented within signal handler,
which is very bad idea. Split sending and receiving in two processes, which fixes this problem and will help to sandbox rwhod. Submitted by: Mariusz Zaborski <oshogbo@FreeBSD.org> Sponsored by: Google Summer of Code 2013 Reviewed by: pjd MFC after: 1 month
This commit is contained in:
Pawel Jakub Dawidek
parent
90173d7dc6
commit
223eee088f
@ -1,5 +1,6 @@
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/*-
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* Copyright (c) 1983, 1993 The Regents of the University of California.
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* Copyright (c) 2013 Mariusz Zaborski <oshogbo@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -48,6 +49,8 @@ __FBSDID("$FreeBSD$");
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#include <sys/signal.h>
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#include <sys/ioctl.h>
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#include <sys/sysctl.h>
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#include <sys/procdesc.h>
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#include <sys/wait.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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@ -93,10 +96,10 @@ struct sockaddr_in multicast_addr =
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{ sizeof(multicast_addr), AF_INET, 0, { 0 }, { 0 } };
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/*
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* Alarm interval. Don't forget to change the down time check in ruptime
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* Sleep interval. Don't forget to change the down time check in ruptime
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* if this is changed.
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*/
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#define AL_INTERVAL (3 * 60)
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#define SL_INTERVAL (3 * 60)
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char myname[MAXHOSTNAMELEN];
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@ -117,15 +120,18 @@ struct neighbor *neighbors;
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struct whod mywd;
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struct servent *sp;
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int s;
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int fdp;
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pid_t pid_child_receiver;
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#define WHDRSIZE (int)(sizeof(mywd) - sizeof(mywd.wd_we))
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int configure(int so);
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void getboottime(int signo __unused);
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void onalrm(int signo __unused);
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void receiver_process(void);
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void rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo);
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void run_as(uid_t *uid, gid_t *gid);
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void quit(const char *msg);
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void sender_process(void);
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int verify(char *name, int maxlen);
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static void usage(void);
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@ -168,9 +174,6 @@ void Sendto(int s, const void *buf, size_t cc, int flags,
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int
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main(int argc, char *argv[])
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{
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struct sockaddr_in from;
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struct stat st;
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char path[64];
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int on;
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char *cp;
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struct sockaddr_in soin;
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@ -269,16 +272,83 @@ main(int argc, char *argv[])
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if (!configure(s))
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exit(1);
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if (!quiet_mode) {
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signal(SIGALRM, onalrm);
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onalrm(0);
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pid_child_receiver = pdfork(&fdp, 0);
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if (pid_child_receiver == 0) {
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receiver_process();
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} else if (pid_child_receiver > 0) {
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sender_process();
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} else if (pid_child_receiver == -1) {
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syslog(LOG_ERR, "pdfork: %m");
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exit(1);
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}
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} else {
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receiver_process();
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}
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for (;;) {
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struct whod wd;
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socklen_t len;
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int cc, whod;
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time_t t;
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}
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len = sizeof(from);
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static void
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usage(void)
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{
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fprintf(stderr, "usage: rwhod [-i] [-p] [-l] [-m [ttl]]\n");
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exit(1);
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}
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void
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run_as(uid_t *uid, gid_t *gid)
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{
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struct passwd *pw;
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struct group *gr;
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pw = getpwnam(UNPRIV_USER);
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if (pw == NULL) {
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syslog(LOG_ERR, "getpwnam(%s): %m", UNPRIV_USER);
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exit(1);
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}
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*uid = pw->pw_uid;
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gr = getgrnam(UNPRIV_GROUP);
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if (gr == NULL) {
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syslog(LOG_ERR, "getgrnam(%s): %m", UNPRIV_GROUP);
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exit(1);
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}
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*gid = gr->gr_gid;
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}
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/*
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* Check out host name for unprintables
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* and other funnies before allowing a file
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* to be created. Sorry, but blanks aren't allowed.
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*/
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int
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verify(char *name, int maxlen)
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{
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int size;
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size = 0;
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while (*name != '\0' && size < maxlen - 1) {
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if (!isascii(*name) || !isalnum(*name) || ispunct(*name))
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return (0);
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name++;
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size++;
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}
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*name = '\0';
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return (size > 0);
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}
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void
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receiver_process(void)
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{
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struct sockaddr_in from;
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struct stat st;
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char path[64];
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struct whod wd;
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socklen_t len;
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int cc, whod;
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time_t t;
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len = sizeof(from);
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for (;;) {
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cc = recvfrom(s, &wd, sizeof(wd), 0, (struct sockaddr *)&from,
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&len);
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if (cc <= 0) {
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@ -344,139 +414,97 @@ main(int argc, char *argv[])
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}
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}
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static void
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usage(void)
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{
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fprintf(stderr, "usage: rwhod [-i] [-p] [-l] [-m [ttl]]\n");
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exit(1);
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}
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void
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run_as(uid_t *uid, gid_t *gid)
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sender_process(void)
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{
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struct passwd *pw;
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struct group *gr;
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pw = getpwnam(UNPRIV_USER);
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if (pw == NULL) {
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syslog(LOG_ERR, "getpwnam(%s): %m", UNPRIV_USER);
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exit(1);
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}
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*uid = pw->pw_uid;
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gr = getgrnam(UNPRIV_GROUP);
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if (gr == NULL) {
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syslog(LOG_ERR, "getgrnam(%s): %m", UNPRIV_GROUP);
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exit(1);
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}
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*gid = gr->gr_gid;
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}
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/*
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* Check out host name for unprintables
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* and other funnies before allowing a file
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* to be created. Sorry, but blanks aren't allowed.
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*/
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int
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verify(char *name, int maxlen)
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{
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int size;
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size = 0;
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while (*name != '\0' && size < maxlen - 1) {
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if (!isascii(*name) || !isalnum(*name) || ispunct(*name))
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return (0);
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name++;
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size++;
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}
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*name = '\0';
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return (size > 0);
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}
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void
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onalrm(int signo __unused)
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{
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static int alarmcount = 0;
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int sendcount;
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double avenrun[3];
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time_t now;
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int i, cc;
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int i, cc, status;
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struct utmpx *ut;
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struct stat stb;
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struct neighbor *np;
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struct whoent *we, *wend;
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we = mywd.wd_we;
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now = time(NULL);
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if (alarmcount % 10 == 0)
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getboottime(0);
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alarmcount++;
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wend = &mywd.wd_we[1024 / sizeof(struct whoent)];
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setutxent();
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while ((ut = getutxent()) != NULL && we < wend) {
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if (ut->ut_type != USER_PROCESS)
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continue;
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strncpy(we->we_utmp.out_line, ut->ut_line,
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sizeof(we->we_utmp.out_line));
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strncpy(we->we_utmp.out_name, ut->ut_user,
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sizeof(we->we_utmp.out_name));
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we->we_utmp.out_time =
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htonl(_time_to_time32(ut->ut_tv.tv_sec));
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we++;
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}
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endutxent();
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sendcount = 0;
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for (;;) {
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we = mywd.wd_we;
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now = time(NULL);
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if (sendcount % 10 == 0)
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getboottime(0);
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sendcount++;
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wend = &mywd.wd_we[1024 / sizeof(struct whoent)];
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setutxent();
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while ((ut = getutxent()) != NULL && we < wend) {
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if (ut->ut_type != USER_PROCESS)
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continue;
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strncpy(we->we_utmp.out_line, ut->ut_line,
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sizeof(we->we_utmp.out_line));
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strncpy(we->we_utmp.out_name, ut->ut_user,
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sizeof(we->we_utmp.out_name));
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we->we_utmp.out_time =
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htonl(_time_to_time32(ut->ut_tv.tv_sec));
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we++;
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}
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endutxent();
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if (chdir(_PATH_DEV) < 0) {
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syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
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exit(1);
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}
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wend = we;
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for (we = mywd.wd_we; we < wend; we++) {
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if (stat(we->we_utmp.out_line, &stb) >= 0)
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we->we_idle = htonl(now - stb.st_atime);
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we++;
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}
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(void) getloadavg(avenrun, sizeof(avenrun) / sizeof(avenrun[0]));
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for (i = 0; i < 3; i++)
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mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
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cc = (char *)wend - (char *)&mywd;
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mywd.wd_sendtime = htonl(_time_to_time32(time(NULL)));
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mywd.wd_vers = WHODVERSION;
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mywd.wd_type = WHODTYPE_STATUS;
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if (multicast_mode == SCOPED_MULTICAST) {
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(void) sendto(s, (char *)&mywd, cc, 0,
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(struct sockaddr *)&multicast_addr,
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sizeof(multicast_addr));
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} else {
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for (np = neighbors; np != NULL; np = np->n_next) {
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if (multicast_mode == PER_INTERFACE_MULTICAST &&
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(np->n_flags & IFF_MULTICAST) != 0) {
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/*
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* Select the outgoing interface for the
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* multicast.
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*/
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if (setsockopt(s, IPPROTO_IP,
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IP_MULTICAST_IF,
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&(((struct sockaddr_in *)np->n_addr)->sin_addr),
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sizeof(struct in_addr)) < 0) {
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syslog(LOG_ERR,
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"setsockopt IP_MULTICAST_IF: %m");
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exit(1);
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if (chdir(_PATH_DEV) < 0) {
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syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
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exit(1);
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}
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wend = we;
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for (we = mywd.wd_we; we < wend; we++) {
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if (stat(we->we_utmp.out_line, &stb) >= 0)
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we->we_idle = htonl(now - stb.st_atime);
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we++;
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}
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(void) getloadavg(avenrun,
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sizeof(avenrun) / sizeof(avenrun[0]));
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for (i = 0; i < 3; i++)
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mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
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cc = (char *)wend - (char *)&mywd;
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mywd.wd_sendtime = htonl(_time_to_time32(time(NULL)));
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mywd.wd_vers = WHODVERSION;
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mywd.wd_type = WHODTYPE_STATUS;
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if (multicast_mode == SCOPED_MULTICAST) {
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(void) sendto(s, (char *)&mywd, cc, 0,
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(struct sockaddr *)&multicast_addr,
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sizeof(multicast_addr));
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} else {
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for (np = neighbors; np != NULL; np = np->n_next) {
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if (multicast_mode == PER_INTERFACE_MULTICAST &&
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(np->n_flags & IFF_MULTICAST) != 0) {
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/*
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* Select the outgoing interface for the
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* multicast.
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*/
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if (setsockopt(s, IPPROTO_IP,
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IP_MULTICAST_IF,
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&(((struct sockaddr_in *)np->n_addr)->sin_addr),
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sizeof(struct in_addr)) < 0) {
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syslog(LOG_ERR,
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"setsockopt IP_MULTICAST_IF: %m");
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exit(1);
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}
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(void) sendto(s, (char *)&mywd, cc, 0,
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(struct sockaddr *)&multicast_addr,
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sizeof(multicast_addr));
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} else {
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(void) sendto(s, (char *)&mywd, cc, 0,
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np->n_addr, np->n_addrlen);
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}
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(void) sendto(s, (char *)&mywd, cc, 0,
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(struct sockaddr *)&multicast_addr,
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sizeof(multicast_addr));
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} else {
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(void) sendto(s, (char *)&mywd, cc, 0,
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np->n_addr, np->n_addrlen);
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}
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}
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if (chdir(_PATH_RWHODIR) < 0) {
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syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
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exit(1);
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}
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if (waitpid(pid_child_receiver, &status, WNOHANG) ==
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pid_child_receiver) {
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break;
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}
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sleep(SL_INTERVAL);
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}
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if (chdir(_PATH_RWHODIR) < 0) {
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syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
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exit(1);
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}
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(void) alarm(AL_INTERVAL);
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}
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void
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