49 lines
1.2 KiB
Diff
49 lines
1.2 KiB
Diff
--- log.c
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+++ log.c
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@@ -50,6 +50,7 @@
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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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@@ -313,6 +314,7 @@
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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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if (level > log_level)
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return;
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@@ -351,6 +353,7 @@
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pri = LOG_ERR;
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break;
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}
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+
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if (txt != NULL) {
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snprintf(fmtbuf, sizeof(fmtbuf), "%s: %s", txt, fmt);
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vsnprintf(msgbuf, sizeof(msgbuf), fmtbuf, args);
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@@ -363,6 +366,14 @@
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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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@@ -372,5 +383,6 @@
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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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}
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