42 lines
1.1 KiB
Diff
42 lines
1.1 KiB
Diff
--- log.c
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+++ log.c
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@@ -51,6 +51,7 @@
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#include "xmalloc.h"
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#include "log.h"
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+#include <signal.h>
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static LogLevel log_level = SYSLOG_LEVEL_INFO;
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static int log_on_stderr = 1;
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@@ -336,6 +337,7 @@
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char fmtbuf[MSGBUFSIZ];
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char *txt = NULL;
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int pri = LOG_INFO;
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+ sigset_t nset, oset;
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int saved_errno = errno;
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if (level > log_level)
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@@ -387,6 +389,14 @@
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snprintf(msgbuf, sizeof msgbuf, "%s\r\n", fmtbuf);
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write(STDERR_FILENO, msgbuf, strlen(msgbuf));
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} else {
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+ /* Prevent a race between the grace_alarm
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+ * which writes a log message and terminates
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+ * and main sshd code that leads to deadlock
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+ * as syslog is not async safe.
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+ */
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+ sigemptyset(&nset);
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+ sigaddset(&nset, SIGALRM);
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+ sigprocmask(SIG_BLOCK, &nset, &oset);
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#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
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openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
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syslog_r(pri, &sdata, "%.500s", fmtbuf);
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@@ -396,6 +406,7 @@
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syslog(pri, "%.500s", fmtbuf);
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closelog();
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#endif
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+ sigprocmask(SIG_SETMASK, &oset, NULL);
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}
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errno = saved_errno;
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}
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