Prevent buffer overrun in log_event().

[nssm.git] / event.cpp

diff --git a/event.cpp b/event.cpp
index 661761d..32e4acf 100644 (file)
--- a/event.cpp
+++ b/event.cpp
@@ -1,11 +1,41 @@
 #include "nssm.h"\r
 \r
+#define NSSM_ERROR_BUFSIZE 65535\r
+#define NSSM_NUM_EVENT_STRINGS 16\r
+unsigned long tls_index;\r
+\r
+/* Convert error code to error string - must call LocalFree() on return value */\r
+char *error_string(unsigned long error) {\r
+  /* Thread-safe buffer */\r
+  char *error_message = (char *) TlsGetValue(tls_index);\r
+  if (! error_message) {\r
+    error_message = (char *) LocalAlloc(LPTR, NSSM_ERROR_BUFSIZE);\r
+    if (! error_message) return "<out of memory for error message>";\r
+    TlsSetValue(tls_index, (void *) error_message);\r
+  }\r
+\r
+  if (! FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, 0, error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (char *) error_message, NSSM_ERROR_BUFSIZE, 0)) {\r
+    if (_snprintf_s(error_message, NSSM_ERROR_BUFSIZE, _TRUNCATE, "system error %lu", error) < 0) return 0;\r
+  }\r
+  return error_message;\r
+}\r
+\r
+/* Convert message code to format string */\r
+char *message_string(unsigned long error) {\r
+  char *ret;\r
+  if (! FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_HMODULE | FORMAT_MESSAGE_IGNORE_INSERTS, 0, error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR) &ret, NSSM_ERROR_BUFSIZE, 0)) {\r
+    ret = (char *) HeapAlloc(GetProcessHeap(), 0, 32);\r
+    if (_snprintf_s(ret, NSSM_ERROR_BUFSIZE, _TRUNCATE, "system error %lu", error) < 0) return 0;\r
+  }\r
+  return ret;\r
+}\r
+\r
 /* Log a message to the Event Log */\r
 void log_event(unsigned short type, unsigned long id, ...) {\r
   va_list arg;\r
   int count;\r
   char *s;\r
-  char *strings[6];\r
+  char *strings[NSSM_NUM_EVENT_STRINGS];\r
 \r
   /* Open event log */\r
   HANDLE handle = RegisterEventSource(0, TEXT(NSSM));\r
@@ -14,10 +44,50 @@ void log_event(unsigned short type, unsigned long id, ...) {
   /* Log it */\r
   count = 0;\r
   va_start(arg, id);\r
-  while ((s = va_arg(arg, char *))) strings[count++] = s;\r
+  while ((s = va_arg(arg, char *)) && count < NSSM_NUM_EVENT_STRINGS - 1) strings[count++] = s;\r
+  strings[count] = 0;\r
   va_end(arg);\r
   ReportEvent(handle, type, 0, id, 0, count, 0, (const char **) strings, 0);\r
 \r
   /* Close event log */\r
   DeregisterEventSource(handle);\r
 }\r
+\r
+/* Log a message to the console */\r
+void print_message(FILE *file, unsigned long id, ...) {\r
+  va_list arg;\r
+\r
+  char *format = message_string(id);\r
+  if (! format) return;\r
+\r
+  va_start(arg, id);\r
+  vfprintf(file, format, arg);\r
+  va_end(arg);\r
+\r
+  LocalFree(format);\r
+}\r
+\r
+/* Show a GUI dialogue */\r
+int popup_message(unsigned int type, unsigned long id, ...) {\r
+  va_list arg;\r
+\r
+  char *format = message_string(id);\r
+  if (! format) {\r
+    return MessageBox(0, "Message %lu was supposed to go here!", NSSM, MB_OK | MB_ICONEXCLAMATION);\r
+  }\r
+\r
+  char blurb[256];\r
+  va_start(arg, id);\r
+  if (vsnprintf_s(blurb, sizeof(blurb), _TRUNCATE, format, arg) < 0) {\r
+    va_end(arg);\r
+    LocalFree(format);\r
+    return MessageBox(0, "Message %lu was supposed to go here!", NSSM, MB_OK | MB_ICONEXCLAMATION);\r
+  }\r
+  va_end(arg);\r
+\r
+  int ret = MessageBox(0, blurb, NSSM, type);\r
+\r
+  LocalFree(format);\r
+\r
+  return ret;\r
+}\r