When send()ing to syslogd return ENOBUFS keep trying until success.
This fixes a case, when DoSed syslogd completely loses messages. PR: bin/72366 Discussed with: dwmalone, millert@OpenBSD.org Approved by: julian (mentor) Obtained from: OpenBSD (rev. 1.17, 1.21 by millert) MFC after: 3 months
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=136283
@ -243,17 +243,27 @@ vsyslog(pri, fmt, ap)
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if (!opened)
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openlog(LogTag, LogStat | LOG_NDELAY, 0);
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connectlog();
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if (send(LogFile, tbuf, cnt, 0) >= 0)
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return;
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/*
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* If the send() failed, the odds are syslogd was restarted.
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* Make one (only) attempt to reconnect to /dev/log.
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* If the send() failed, there are two likely scenarios:
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* 1) syslogd was restarted
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* 2) /var/run/log is out of socket buffer space
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* We attempt to reconnect to /var/run/log to take care of
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* case #1 and keep send()ing data to cover case #2
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* to give syslogd a chance to empty its socket buffer.
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*/
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disconnectlog();
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connectlog();
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if (send(LogFile, tbuf, cnt, 0) >= 0)
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return;
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if (send(LogFile, tbuf, cnt, 0) < 0) {
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if (errno != ENOBUFS) {
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disconnectlog();
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connectlog();
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}
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do {
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usleep(1);
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if (send(LogFile, tbuf, cnt, 0) >= 0)
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break;
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} while (errno == ENOBUFS);
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}
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/*
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* Output the message to the console; try not to block
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