Add ability to send SAL_* messages to syslog

Use environment variable SAL_LOG_SYSLOG=1

Change-Id: I0c260ca69fbeefb0c2e8cc46ca6955e92791c05b
Signed-off-by: Stephan Bergmann <sbergman@redhat.com>

config/config_global.h.in

@@ -13,3 +13,4 @@ Any change in this header will cause a rebuild of almost everything.
 #undef HAVE_GCC_BUILTIN_ATOMIC
 #undef HAVE_SFINAE_ANONYMOUS_BROKEN
 #undef HAVE_THREADSAFE_STATICS
+#undef HAVE_SYSLOG_H

configure.ac

@@ -4257,7 +4257,10 @@ SOURCEVERSION="OOO$UPD"
 AC_SUBST(UPD)
 AC_SUBST(SOURCEVERSION)
 
-
+dnl ===================================================================
+dnl Check for syslog header
+dnl ===================================================================
+AC_CHECK_HEADER(syslog.h, AC_DEFINE(HAVE_SYSLOG_H))
 
 dnl ===================================================================
 dnl Set the ENABLE_CRASHDUMP variable.

sal/osl/all/log.cxx

@@ -56,6 +56,12 @@
 #define OSL_DETAIL_GETPID getpid()
 #endif
 
+#ifdef HAVE_SYSLOG_H
+#include <syslog.h>
+// sal/osl/unx/salinit.cxx::sal_detail_initialize updates this:
+bool sal_use_syslog;
+#endif
+
 // Avoid the use of other sal code in this file as much as possible, so that
 // this code can be called from other sal code without causing endless
 // recursion.
@@ -96,6 +102,22 @@ char const * getEnvironmentVariable() {
     return p2;
 }
 
+#ifdef HAVE_SYSLOG_H
+int toSyslogPriority(sal_detail_LogLevel level) {
+    switch (level) {
+    default:
+        assert(false); // this cannot happen
+        // fall through
+    case SAL_DETAIL_LOG_LEVEL_INFO:
+        return LOG_INFO;
+    case SAL_DETAIL_LOG_LEVEL_WARN:
+        return LOG_WARNING;
+    case SAL_DETAIL_LOG_LEVEL_DEBUG:
+        return LOG_DEBUG;
+    }
+}
+#endif
+
 bool report(sal_detail_LogLevel level, char const * area) {
     if (level == SAL_DETAIL_LOG_LEVEL_DEBUG)
         return true;
@@ -167,14 +189,23 @@ void log(
     char const * message)
 {
     std::ostringstream s;
+#ifdef HAVE_SYSLOG_H
+    if (!sal_use_syslog)
+#endif
+        s << toString(level) << ':';
     if (level == SAL_DETAIL_LOG_LEVEL_DEBUG) {
-        s << toString(level) << ':' << /*no where*/' ' << message << '\n';
+        s << /*no where*/' ' << message << '\n';
     } else {
-        s << toString(level) << ':' << area << ':' << OSL_DETAIL_GETPID << ':'
+        s << area << ':' << OSL_DETAIL_GETPID << ':'
             << osl::Thread::getCurrentIdentifier() << ':' << where << message
             << '\n';
     }
-    std::fputs(s.str().c_str(), stderr);
+#ifdef HAVE_SYSLOG_H
+    if (sal_use_syslog)
+        syslog(toSyslogPriority(level), "%s", s.str().c_str());
+    else
+#endif
+        std::fputs(s.str().c_str(), stderr);
 }
 
 }

sal/osl/unx/salinit.cxx

@@ -29,6 +29,13 @@
 #include "sal/main.h"
 #include "sal/types.h"
 
+#ifdef HAVE_SYSLOG_H
+#include <string.h>
+#include <syslog.h>
+// from sal/osl/all/log.cxx:
+extern bool sal_use_syslog;
+#endif
+
 extern "C" {
 
 void sal_detail_initialize(int argc, char ** argv) {
@@ -57,6 +64,12 @@ void sal_detail_initialize(int argc, char ** argv) {
         close(fd);
     }
 #endif
+#ifdef HAVE_SYSLOG_H
+    const char *use_syslog = getenv("SAL_LOG_SYSLOG");
+    sal_use_syslog = use_syslog != NULL && !strcmp(use_syslog, "1");
+    if (sal_use_syslog)
+        openlog("libreoffice", 0, LOG_USER);
+#endif
 
     osl_setCommandArgs(argc, argv);
 }