docs/logging_and_backgrounding.txt: new mini-doc
dnsd: remove statics, remove nerly-useless SIGINT handler crond: correct more of logfile to 0666 (as usual, umask allows user to remove unwanted bits). nameif: print errors to stderr too, not just to syslog function old new delta udhcp_read_interface 308 306 -2 ttl 4 - -4 fileconf 4 - -4 dnsentry 4 - -4 interrupt 19 - -19 dnsd_main 1463 1394 -69 ------------------------------------------------------------------------------ (add/remove: 0/4 grow/shrink: 0/2 up/down: 0/-102) Total: -102 bytes text data bss dec hex filename 808161 476 7864 816501 c7575 busybox_old 807994 468 7856 816318 c74be busybox_unstripped
This commit is contained in:
Denis Vlasenko
parent
4774179cb9
commit
a19e64933c
89
docs/logging_and_backgrounding.txt
Normal file
89
docs/logging_and_backgrounding.txt
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@ -0,0 +1,89 @@
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Logging and backgrounding
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By default, bb_[p]error_msg[_and_die] messages go to stderr,
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and of course, usually applets do not auto-background. :)
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Historically, daemons and inetd services are different.
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Busybox is trying to provide compatible behavior, thus if an applet
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is emulating an existing utility, it should mimic it. If utility
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auto-backgrounds itself, busybox applet should do the same.
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If utility normally logs to syslog, busybox applet should do
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the same too.
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However, busybox should not needlessly restrict the freedom
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of the users. And users have different needs and different preferences.
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Some might like logging everything from daemons to syslog.
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Others prefer running stuff under runsv/svlogd and thus would like
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logging to stderr and no daemonization.
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To help with that, busybox applets should have options to override
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default behavior, whatever that is for a given applet.
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Current sutiation is a bit of a mess:
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acpid - auto-backgrounds unless -d
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crond - auto-backgrounds unless -f, logs to syslog unless -d or -L.
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option -d logs to stderr, -L FILE logs to FILE
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devfsd - (obsolete)
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dnsd - option -d makes it auto-background and log to syslog
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fakeidentd - inetd service. Auto-backgrounds and logs to syslog
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if no -f and no -i and no -w (-i is "inetd service" flag,
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-w is "inetd-wait service" flag)
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ftpd - inetd service. Logs to syslog always, with -v logs to strerr too
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httpd - auto-backgrounds unless -f or -i
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(-i is "inetd service" flag)
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inetd - auto-backgrounds unless -f, logs to syslog unless -e
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klogd - auto-backgrounds unless -n
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syslogd - auto-backgrounds unless -n
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telnetd - auto-backgrounds unless -f or -i
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(-i is "inetd service" flag)
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udhcpc - auto-backgrounds unless -f after lease is obtained,
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option -b makes it background sooner (when lease attempt
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fails and retries start),
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after backgrounding it stops logging to stderr;
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logs to stderr, but option -S makes it log *also* to syslog
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udhcpd - auto-backgrounds and do not log to stderr unless -f,
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otherwise logs to stderr, but option -S makes it log *also* to syslog
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zcip - auto-backgrounds and logs *also* to syslog unless -f
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miscutils/crond.c: logmode = LOGMODE_SYSLOG;
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networking/dnsd.c: logmode = LOGMODE_SYSLOG;
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networking/ftpd.c: logmode = LOGMODE_SYSLOG;
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networking/ftpd.c: logmode |= LOGMODE_SYSLOG;
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networking/inetd.c: logmode = LOGMODE_SYSLOG;
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networking/isrv_identd.c: logmode = LOGMODE_SYSLOG;
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networking/telnetd.c: logmode = LOGMODE_SYSLOG;
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networking/udhcp/dhcpc.c: logmode = LOGMODE_NONE;
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networking/udhcp/dhcpc.c: logmode |= LOGMODE_SYSLOG;
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networking/udhcp/dhcpc.c: logmode &= ~LOGMODE_STDIO;
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networking/udhcp/dhcpd.c: logmode = LOGMODE_NONE;
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networking/udhcp/dhcpd.c: logmode |= LOGMODE_SYSLOG;
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networking/zcip.c: logmode |= LOGMODE_SYSLOG;
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These daemons seem to never auto-background/log to syslog:
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lpd - inetd service. Has nothing to log so far, though
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dhcprelay - standard behavior
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inotifyd - standard behavior
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runsv - standard behavior
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runsvdir - standard behavior
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svlogd - standard behavior
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tcpsvd, udpsvd - standard behavior
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tftpd - standard behavior
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Non-daemons (seems to be use syslog for a good reason):
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networking/nameif.c: logmode |= LOGMODE_SYSLOG;
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loginutils/chpasswd.c: logmode = LOGMODE_BOTH;
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loginutils/chpasswd.c: logmode = LOGMODE_STDIO;
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loginutils/getty.c: logmode = LOGMODE_BOTH;
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loginutils/getty.c: logmode = LOGMODE_NONE;
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loginutils/passwd.c: logmode = LOGMODE_STDIO;
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loginutils/passwd.c: logmode = LOGMODE_BOTH;
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loginutils/sulogin.c: logmode = LOGMODE_SYSLOG; (used if stdio isn't a tty)
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loginutils/sulogin.c: logmode = LOGMODE_BOTH;
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util-linux/mount.c: logmode = LOGMODE_SYSLOG; (used in a backgrounded NFS mount helper)
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@ -142,7 +142,7 @@ static void crondlog(const char *ctl, ...)
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/* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */
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if (!DebugOpt && LogFile) {
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/* Otherwise (log to file): we reopen log file at every write: */
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int logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0600);
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int logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0666);
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if (logfd >= 0)
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xmove_fd(logfd, STDERR_FILENO);
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}
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@ -63,14 +63,7 @@ struct dns_entry { // element of known name, ip address and reversed ip address
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char name[MAX_HOST_LEN];
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};
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static struct dns_entry *dnsentry;
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static uint32_t ttl = DEFAULT_TTL;
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static const char *fileconf = "/etc/dnsd.conf";
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// Must match getopt32 call
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#define OPT_daemon (option_mask32 & 0x10)
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#define OPT_verbose (option_mask32 & 0x20)
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#define OPT_verbose (option_mask32)
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/*
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@ -88,7 +81,7 @@ static void convname(char *a, uint8_t *q)
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/*
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* Insert length of substrings instead of dots
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*/
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static void undot(uint8_t * rip)
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static void undot(uint8_t *rip)
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{
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int i = 0, s = 0;
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while (rip[i])
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@ -104,13 +97,13 @@ static void undot(uint8_t * rip)
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/*
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* Read hostname/IP records from file
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*/
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static void dnsentryinit(void)
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static struct dns_entry *parse_conf_file(const char *fileconf)
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{
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char *token[2];
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parser_t *parser;
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struct dns_entry *m, *prev;
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struct dns_entry *m, *prev, *conf_data;
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prev = dnsentry = NULL;
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prev = conf_data = NULL;
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parser = config_open(fileconf);
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while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
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unsigned a, b, c, d;
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@ -132,50 +125,54 @@ static void dnsentryinit(void)
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convname(m->name, (uint8_t*)token[0]);
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if (OPT_verbose)
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fprintf(stderr, "\tname:%s, ip:%s\n", &(m->name[1]), m->ip);
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bb_error_msg("name:%s, ip:%s", &(m->name[1]), m->ip);
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if (prev == NULL)
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dnsentry = m;
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conf_data = m;
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else
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prev->next = m;
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prev = m;
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}
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config_close(parser);
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return conf_data;
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}
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/*
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* Look query up in dns records and return answer if found
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* qs is the query string, first byte the string length
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*/
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static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
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static int table_lookup(struct dns_entry *d, uint16_t type, uint8_t *as, uint8_t *qs)
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{
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int i;
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struct dns_entry *d = dnsentry;
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do {
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#if DEBUG
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char *p,*q;
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char *p, *q;
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q = (char *)&(qs[1]);
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p = &(d->name[1]);
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fprintf(stderr, "\n%s: %d/%d p:%s q:%s %d",
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__FUNCTION__, (int)strlen(p), (int)(d->name[0]),
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p, q, (int)strlen(q));
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#endif
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if (type == REQ_A) { /* search by host name */
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if (type == REQ_A) {
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/* search by host name */
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for (i = 1; i <= (int)(d->name[0]); i++)
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if (tolower(qs[i]) != d->name[i])
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break;
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if (i > (int)(d->name[0]) ||
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(d->name[0] == 1 && d->name[1] == '*')) {
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if (i > (int)(d->name[0])
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|| (d->name[0] == 1 && d->name[1] == '*')
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) {
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strcpy((char *)as, d->ip);
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#if DEBUG
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fprintf(stderr, " OK as:%s\n", as);
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#endif
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return 0;
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}
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} else if (type == REQ_PTR) { /* search by IP-address */
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if ((d->name[0] != 1 || d->name[1] != '*') &&
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!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) {
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} else if (type == REQ_PTR) {
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/* search by IP-address */
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if ((d->name[0] != 1 || d->name[1] != '*')
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&& !strncmp(d->rip + 1, (char*)qs + 1, strlen(d->rip)-1)
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) {
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strcpy((char *)as, d->name);
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return 0;
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}
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@ -188,7 +185,7 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
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/*
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* Decode message and generate answer
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*/
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static int process_packet(uint8_t *buf)
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static int process_packet(struct dns_entry *conf_data, uint32_t conf_ttl, uint8_t *buf)
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{
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uint8_t answstr[MAX_NAME_LEN + 1];
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struct dns_head *head;
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@ -240,7 +237,7 @@ static int process_packet(uint8_t *buf)
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// We have a standard query
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bb_info_msg("%s", (char *)from);
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lookup_result = table_lookup(type, answstr, from);
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lookup_result = table_lookup(conf_data, type, answstr, from);
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if (lookup_result != 0) {
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outr_flags = 3 | 0x0400; // name do not exist and auth
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goto empty_packet;
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@ -267,7 +264,7 @@ static int process_packet(uint8_t *buf)
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// and append answer rr
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// FIXME: unaligned accesses??
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*(uint32_t *) answb = htonl(ttl);
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*(uint32_t *) answb = htonl(conf_ttl);
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answb += 4;
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*(uint16_t *) answb = htons(outr_rlen);
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answb += 2;
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@ -290,49 +287,48 @@ static int process_packet(uint8_t *buf)
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/*
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* Exit on signal
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*/
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static void interrupt(int sig)
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{
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/* unlink("/var/run/dnsd.lock"); */
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bb_error_msg("interrupt, exiting\n");
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kill_myself_with_sig(sig);
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}
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//static void interrupt(int sig)
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//{
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// /* unlink("/var/run/dnsd.lock"); */
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// bb_error_msg("interrupt, exiting\n");
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// kill_myself_with_sig(sig);
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//}
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int dnsd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int dnsd_main(int argc UNUSED_PARAM, char **argv)
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{
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const char *listen_interface = "0.0.0.0";
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const char *fileconf = "/etc/dnsd.conf";
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struct dns_entry *conf_data;
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uint32_t conf_ttl = DEFAULT_TTL;
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char *sttl, *sport;
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len_and_sockaddr *lsa, *from, *to;
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unsigned lsa_size;
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int udps;
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int udps, opts;
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uint16_t port = 53;
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/* Paranoid sizing: querystring x2 + ttl + outr_rlen + answstr */
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/* I'd rather see process_packet() fixed instead... */
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uint8_t buf[MAX_PACK_LEN * 2 + 4 + 2 + (MAX_NAME_LEN+1)];
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getopt32(argv, "i:c:t:p:dv", &listen_interface, &fileconf, &sttl, &sport);
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//if (option_mask32 & 0x1) // -i
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//if (option_mask32 & 0x2) // -c
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if (option_mask32 & 0x4) // -t
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ttl = xatou_range(sttl, 1, 0xffffffff);
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if (option_mask32 & 0x8) // -p
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opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport);
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//if (opts & 0x1) // -v
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//if (opts & 0x2) // -i
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//if (opts & 0x4) // -c
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if (opts & 0x8) // -t
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conf_ttl = xatou_range(sttl, 1, 0xffffffff);
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if (opts & 0x10) // -p
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port = xatou_range(sport, 1, 0xffff);
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if (OPT_verbose) {
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bb_info_msg("listen_interface: %s", listen_interface);
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bb_info_msg("ttl: %d, port: %d", ttl, port);
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bb_info_msg("fileconf: %s", fileconf);
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}
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if (OPT_daemon) {
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if (opts & 0x20) { // -d
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bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
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openlog(applet_name, LOG_PID, LOG_DAEMON);
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logmode = LOGMODE_SYSLOG;
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}
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/* Clear all except "verbose" bit */
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option_mask32 &= 1;
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dnsentryinit();
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conf_data = parse_conf_file(fileconf);
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signal(SIGINT, interrupt);
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// signal(SIGINT, interrupt); - just for one message?
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bb_signals(0
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/* why? + (1 << SIGPIPE) */
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+ (1 << SIGHUP)
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@ -371,7 +367,7 @@ int dnsd_main(int argc UNUSED_PARAM, char **argv)
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if (OPT_verbose)
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bb_info_msg("Got UDP packet");
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buf[r] = '\0'; /* paranoia */
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r = process_packet(buf);
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r = process_packet(conf_data, conf_ttl, buf);
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if (r <= 0)
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continue;
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send_to_from(udps, buf, r, 0, &from->u.sa, &to->u.sa, lsa->len);
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@ -1299,7 +1299,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
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if (sep->se_builtin) {
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if (pid) { /* "pid" is -1: we did vfork */
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close(sep->se_fd); /* listening socket */
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logmode = 0; /* make xwrite etc silent */
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logmode = LOGMODE_NONE; /* make xwrite etc silent */
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}
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restore_sigmask(&omask);
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if (sep->se_socktype == SOCK_STREAM)
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@ -144,7 +144,9 @@ int nameif_main(int argc, char **argv)
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if (1 & getopt32(argv, "sc:", &fname)) {
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openlog(applet_name, 0, LOG_LOCAL0);
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logmode = LOGMODE_SYSLOG;
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/* Why not just "="? I assume logging to stderr
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* can't hurt. 2>/dev/null if you don't like it: */
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logmode |= LOGMODE_SYSLOG;
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}
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argc -= optind;
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argv += optind;
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@ -280,7 +280,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
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/* on NOMMU reexec (i.e., background) early */
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if (!(opt & OPT_f)) {
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bb_daemonize_or_rexec(0 /* flags */, argv);
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logmode = 0;
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logmode = LOGMODE_NONE;
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}
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#endif
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if (opt & OPT_S) {
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@ -46,12 +46,10 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
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opt = getopt32(argv, "fS" USE_FEATURE_UDHCP_PORT("P:", &str_P));
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argv += optind;
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if (!(opt & 1)) { /* no -f */
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bb_daemonize_or_rexec(0, argv);
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logmode &= ~LOGMODE_STDIO;
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logmode = LOGMODE_NONE;
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}
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if (opt & 2) { /* -S */
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openlog(applet_name, LOG_PID, LOG_DAEMON);
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logmode |= LOGMODE_SYSLOG;
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@ -57,7 +57,7 @@ int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t
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}
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our_ip = (struct sockaddr_in *) &ifr.ifr_addr;
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*addr = our_ip->sin_addr.s_addr;
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DEBUG("%s (our ip) = %s", ifr.ifr_name, inet_ntoa(our_ip->sin_addr));
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DEBUG("ip of %s = %s", interface, inet_ntoa(our_ip->sin_addr));
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}
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if (ifindex) {
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