Server: Optionally redirect messages to system log

ChangeLog.md

@@ -6,6 +6,10 @@
 1. Added a new Xvnc command-line option (`-noserverkeymap`) that can be used to
 disable the server-side key mapping feature introduced in 3.1 beta1[4].
 
+2. Added a new Xvnc command-line option (`-syslog`) that can be used to
+redirect all TurboVNC Server and X.org errors, warnings, and messages to the
+system log.
+
 
 3.1.2
 =====

unix/Xvnc/programs/Xserver/CMakeLists.txt

@@ -56,6 +56,11 @@ foreach(typeof typeof __typeof__)
 		break()
 	endif()
 endforeach()
+check_symbol_exists(syslog syslog.h HAVE_SYSLOG)
+check_symbol_exists(vsyslog syslog.h HAVE_VSYSLOG)
+if(HAVE_SYSLOG AND HAVE_VSYSLOG)
+	add_definitions(-DDDXOSVERRORF)
+endif()
 set(CMAKE_REQUIRED_LIBRARIES rt)
 check_symbol_exists(clock_gettime time.h HAVE_CLOCK_GETTIME)
 if(HAVE_CLOCK_GETTIME)

unix/Xvnc/programs/Xserver/hw/vnc/init.c

@@ -65,6 +65,10 @@ from the X Consortium.
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
+#ifdef DDXOSVERRORF
+#include <syslog.h>
+#endif
 #include <unistd.h>
 #include <sys/types.h>
 #include <netdb.h>
@@ -116,6 +120,9 @@ static Bool noCursor = FALSE;
 char *desktopName = DEFAULT_DESKTOP_NAME;
 int traceLevel = 0;
 int rfbLEDState = (int)rfbLEDUnknown;
+#ifdef DDXOSVERRORF
+static Bool sysLog = FALSE;
+#endif
 
 char rfbThisHost[256];
 
@@ -706,6 +713,13 @@ int ddxProcessArgument(int argc, char *argv[], int i)
   }
 #endif
 
+#ifdef DDXOSVERRORF
+  if (strcasecmp(argv[i], "-syslog") == 0) {
+    sysLog = TRUE;
+    return 1;
+  }
+#endif
+
   if (strcasecmp(argv[i], "-verbose") == 0) {
     LogSetParameter(XLOG_VERBOSITY, X_DEBUG);
     return 1;
@@ -1663,6 +1677,15 @@ void DDXRingBell(int percent, int pitch, int duration)
 }
 
 
+#ifdef DDXOSVERRORF
+static void OsVendorVErrorF(const char *f, va_list args)
+{
+  if (sysLog)
+    vsyslog(LOG_ERR, f, args);
+}
+#endif
+
+
 void OsVendorInit(void)
 {
   InitRFB();
@@ -1697,11 +1720,21 @@ void OsVendorInit(void)
     rfbAuthPAMSession = FALSE;
   }
 #endif
+#ifdef DDXOSVERRORF
+  if (!OsVendorVErrorFProc && sysLog)
+    OsVendorVErrorFProc = OsVendorVErrorF;
+#endif
 }
 
 
 void OsVendorFatalError(const char *f, va_list args)
 {
+#ifdef DDXOSVERRORF
+  if (sysLog) {
+    syslog(LOG_ERR, "Fatal server error:");
+    vsyslog(LOG_ERR, f, args);
+  }
+#endif
 }
 
 
@@ -1839,14 +1872,18 @@ void ddxUseMsg(void)
   ErrorF("==============================\n");
 #ifndef TURBOVNC_STATIC_XORG_PATHS
   ErrorF("-registrydir dir       specify directory containing protocol.txt\n");
+#endif
+#ifdef DDXOSVERRORF
+  ErrorF("-syslog                redirect all errors/warnings/messages to the system log\n");
 #endif
   ErrorF("-verbose               print all X.org errors, warnings, and messages\n");
   ErrorF("-version               report Xvnc version on stderr\n\n");
 }
 
 
 /*
- * rfbLog prints a time-stamped message to the log file (stderr.)
+ * rfbLog prints a time-stamped message to the log file (stderr or the system
+ * log.)
  */
 
 void rfbLog(char *format, ...)
@@ -1858,23 +1895,41 @@ void rfbLog(char *format, ...)
 
   va_start(args, format);
 
-  time(&clock);
-  strftime(buf, 255, "%d/%m/%Y %H:%M:%S ", localtime(&clock));
-  for (i = 0; i < traceLevel; i++)
-    snprintf(&buf[strlen(buf)], 256 - strlen(buf), "  ");
-  fputs(buf, stderr);
+#ifdef DDXOSVERRORF
+  if (sysLog)
+    /* NOTE: System log entries already have a timestamp. */
+    vsyslog(LOG_INFO, format, args);
+  else
+#endif
+  {
+    time(&clock);
+    strftime(buf, 255, "%d/%m/%Y %H:%M:%S ", localtime(&clock));
+    for (i = 0; i < traceLevel; i++)
+      snprintf(&buf[strlen(buf)], 256 - strlen(buf), "  ");
+    fputs(buf, stderr);
 
-  vfprintf(stderr, format, args);
-  fflush(stderr);
+    vfprintf(stderr, format, args);
+    fflush(stderr);
+  }
 
   va_end(args);
 }
 
 
 void rfbLogPerror(char *str)
 {
-  rfbLog("");
-  perror(str);
+#ifdef DDXOSVERRORF
+  if (sysLog) {
+    if (str && strlen(str) > 0)
+      syslog(LOG_ERR, "%s: %s\n", str, strerror(errno));
+    else
+      syslog(LOG_ERR, "%s\n", strerror(errno));
+  } else
+#endif
+  {
+    rfbLog("");
+    perror(str);
+  }
 }
 
 

unix/Xvnc/programs/Xserver/hw/vnc/rfb.h

@@ -689,7 +689,7 @@ extern int traceLevel;
 
 /*
  * Print a time-stamped message, prefixed by the client ID, to the log file
- * (stderr.)
+ * (stderr or the system log.)
  */
 #define RFBLOGID(format, ...)  rfbLog("[%u] " format, cl->id, ##__VA_ARGS__)
 

unix/Xvnc/programs/Xserver/hw/vnc/rfbssl_openssl.c

@@ -335,7 +335,7 @@ static void rfbErr(const char *format, ...)
 
 static void rfbssl_error(const char *function)
 {
-  char buf[1024];
+  char buf[BUFSIZE];
   unsigned long e = crypto.ERR_get_error();
 
   while (e) {
@@ -354,6 +354,7 @@ rfbSslCtx *rfbssl_init(rfbClientPtr cl, Bool anon)
   DSA *dsa = NULL;
   int flags = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3, priority = 0;
   const char *list = NULL;
+  char buf[BUFSIZE];
 
 #ifdef DLOPENSSL
   if (loadFunctions() == -1)
@@ -443,14 +444,15 @@ rfbSslCtx *rfbssl_init(rfbClientPtr cl, Bool anon)
     rfbssl_error("SSL_new()");
     goto bailout;
   }
-  RFBLOGID("Available cipher suites: ");
+  snprintf(buf, BUFSIZE, "Available cipher suites: ");
   list = ssl.SSL_get_cipher_list(ctx->ssl, priority++);
   while (list) {
-    fprintf(stderr, "%s", list);
+    snprintf(&buf[strlen(buf)], BUFSIZE - strlen(buf), "%s", list);
     list = ssl.SSL_get_cipher_list(ctx->ssl, priority++);
-    if (list) fprintf(stderr, ":");
+    if (list) snprintf(&buf[strlen(buf)], BUFSIZE - strlen(buf), ":");
   }
-  fprintf(stderr, "\n");
+  snprintf(&buf[strlen(buf)], BUFSIZE - strlen(buf), "\n");
+  RFBLOGID("%s", buf);
   if (!(ssl.SSL_set_fd(ctx->ssl, cl->sock))) {
     rfbssl_error("SSL_set_fd()");
     goto bailout;