Rewrote error & log functions to be more general, use longjmp to get out of

trouble and into predictable cleanup functions (one for each of serve,
client & control contexts).  We use 'fatal' to mean 'kill the thread' and
'error' to mean 'don't kill the thread', assuming some recovery action,
except I don't use error anywhere yet.

src/util.h

@@ -3,36 +3,106 @@
 
 #include <stdio.h>
 #include <pthread.h>
-
-void error_init();
-
-void error(int consult_errno, int fatal, int close_socket, pthread_mutex_t* unlock, const char* format, ...);
+#include <string.h>
+#include <errno.h>
 
 void* xrealloc(void* ptr, size_t size);
-
 void* xmalloc(size_t size);
 
-void set_debug(int value);
+typedef void (cleanup_handler)(void* /* context */, int /* is fatal? */);
+
+/* set from 0 - 5 depending on what level of verbosity you want */
+extern int log_level;
+
+/* set up the error globals */
+void error_init();
+
+/* error_set_handler must be a macro not a function due to setjmp stack rules */
+#include <setjmp.h>
+
+struct error_handler_context {
+	jmp_buf          jmp;
+	cleanup_handler* handler;
+	void*            data;
+};
+
+#define DECLARE_ERROR_CONTEXT(name) \
+  struct error_handler_context *name = (struct error_handler_context*) \
+  pthread_getspecific(cleanup_handler_key)
+
+/* clean up with the given function & data when error_handler() is invoked,
+ * non-fatal errors will also return here (if that's dangerous, use fatal()
+ * instead of error()).
+ *
+ * error handlers are thread-local, so you need to call this when starting a
+ * new thread.
+ */
+extern pthread_key_t cleanup_handler_key;
+#define error_set_handler(cleanfn, cleandata) \
+{ \
+	DECLARE_ERROR_CONTEXT(old); \
+	struct error_handler_context *context = \
+	  xmalloc(sizeof(struct error_handler_context)); \
+	context->handler = (cleanfn); \
+	context->data = (cleandata); \
+	\
+	switch (setjmp(context->jmp)) \
+	{ \
+	case 0: /* setup time */ \
+		if (old) \
+			free(old); \
+		pthread_setspecific(cleanup_handler_key, context); \
+		break; \
+	case 1: /* fatal error, terminate thread */ \
+		context->handler(context->data, 1); \
+		pthread_exit((void*) 1); \
+		abort(); \
+	case 2: /* non-fatal error, return to context of error handler setup */ \
+		context->handler(context->data, 0); \
+	default: \
+		abort(); \
+	} \
+}
+
+
+/* invoke the error handler - longjmps away, don't use directly */
+void error_handler(int fatal);
+
+/* mylog a line at the given level (0 being most verbose) */
+void mylog(int line_level, const char* format, ...);
+
 #ifdef DEBUG
-void debug(const char*msg, ...);
+#  define debug(msg, ...) mylog(0, "%s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__)
 #else
-/* no-op */
-#  define debug( msg, ...)
+#  define debug(msg, ...) /* no-op */
 #endif
 
-#define CLIENT_ERROR(msg, ...) \
-  error(0, 0, client->socket, &client->serve->l_io, msg, ##__VA_ARGS__)
-#define CLIENT_ERROR_ON_FAILURE(test, msg, ...) \
-  if (test < 0) { error(1, 0, client->socket, &client->serve->l_io, msg, ##__VA_ARGS__); }
+/* informational message, not expected to be compiled out */
+#define info(msg, ...) mylog(1, "%s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__)
 
-#define SERVER_ERROR(msg, ...) \
-  error(0, 1, 0, NULL, msg, ##__VA_ARGS__)
-#define SERVER_ERROR_ON_FAILURE(test, msg, ...) \
-  if (test < 0) { error(1, 1, 0, NULL, msg, ##__VA_ARGS__); }
+/* messages that might indicate a problem */
+#define warn(msg, ...) mylog(2, "%s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__)
 
+/* mylog a message and invoke the error handler to recover */
+#define error(msg, ...) { \
+	mylog(3, "*** %s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__); \
+	error_handler(0); \
+}
 
-#define NULLCHECK(x) \
-	do { if ( NULL == (x) ) { SERVER_ERROR( "Null " #x "." ); } } while(0)
+/* mylog a message and invoke the error handler to kill the current thread */
+#define fatal(msg, ...) { \
+	mylog(4, "*** %s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__); \
+	error_handler(1); \
+}
+
+#define ERROR_IF_NULL(value, msg, ...) if (NULL == value) error(msg " (errno=%d, %s)", ##__VA_ARGS__, errno, strerror(errno))
+#define ERROR_IF_NEGATIVE(value, msg, ...) if (value < 0) error(msg, ##__VA_ARGS__)
+#define ERROR_IF_ZERO(value, msg, ...) if (0 == value) error(msg, ##__VA_ARGS__)
+#define FATAL_IF_NULL(value, msg, ...) if (NULL == value) fatal(msg, ##__VA_ARGS__)
+#define FATAL_IF_NEGATIVE(value, msg, ...) if (value < 0) fatal(msg " (errno=%d, %s)", ##__VA_ARGS__, errno, strerror(errno))
+#define FATAL_IF_ZERO(value, msg, ...) if (0 == value) fatal(msg, ##__VA_ARGS__)
+
+#define NULLCHECK(value) FATAL_IF_NULL(value, "BUG: " #value " is null")
 
 #endif