Merge pull request #41 from ppelleti/winsock-errs

FormatMessage for winsock errors

event.c

@@ -3468,6 +3468,8 @@ event_global_setup_locks_(const int enable_locks)
 #endif
 	if (evsig_global_setup_locks_(enable_locks) < 0)
 		return -1;
+	if (evutil_global_setup_locks_(enable_locks) < 0)
+		return -1;
 	if (evutil_secure_rng_global_setup_locks_(enable_locks) < 0)
 		return -1;
 	return 0;

evthread-internal.h

@@ -373,6 +373,7 @@ void *evthread_setup_global_lock_(void *lock_, unsigned locktype,
 
 int event_global_setup_locks_(const int enable_locks);
 int evsig_global_setup_locks_(const int enable_locks);
+int evutil_global_setup_locks_(const int enable_locks);
 int evutil_secure_rng_global_setup_locks_(const int enable_locks);
 
 #endif

evutil.c

@@ -81,11 +81,14 @@
 #include "util-internal.h"
 #include "log-internal.h"
 #include "mm-internal.h"
+#include "evthread-internal.h"
 
 #include "strlcpy-internal.h"
 #include "ipv6-internal.h"
 
 #ifdef _WIN32
+#define HT_NO_CACHE_HASH_VALUES
+#include "ht-internal.h"
 #define open _open
 #define read _read
 #define close _close
@@ -1597,80 +1600,177 @@ evutil_gai_strerror(int err)
 }
 
 #ifdef _WIN32
-#define E(code, s) { code, (s " [" #code " ]") }
-static struct { int code; const char *msg; } windows_socket_errors[] = {
-  E(WSAEINTR, "Interrupted function call"),
-  E(WSAEACCES, "Permission denied"),
-  E(WSAEFAULT, "Bad address"),
-  E(WSAEINVAL, "Invalid argument"),
-  E(WSAEMFILE, "Too many open files"),
-  E(WSAEWOULDBLOCK,  "Resource temporarily unavailable"),
-  E(WSAEINPROGRESS, "Operation now in progress"),
-  E(WSAEALREADY, "Operation already in progress"),
-  E(WSAENOTSOCK, "Socket operation on nonsocket"),
-  E(WSAEDESTADDRREQ, "Destination address required"),
-  E(WSAEMSGSIZE, "Message too long"),
-  E(WSAEPROTOTYPE, "Protocol wrong for socket"),
-  E(WSAENOPROTOOPT, "Bad protocol option"),
-  E(WSAEPROTONOSUPPORT, "Protocol not supported"),
-  E(WSAESOCKTNOSUPPORT, "Socket type not supported"),
-  /* What's the difference between NOTSUPP and NOSUPPORT? :) */
-  E(WSAEOPNOTSUPP, "Operation not supported"),
-  E(WSAEPFNOSUPPORT,  "Protocol family not supported"),
-  E(WSAEAFNOSUPPORT, "Address family not supported by protocol family"),
-  E(WSAEADDRINUSE, "Address already in use"),
-  E(WSAEADDRNOTAVAIL, "Cannot assign requested address"),
-  E(WSAENETDOWN, "Network is down"),
-  E(WSAENETUNREACH, "Network is unreachable"),
-  E(WSAENETRESET, "Network dropped connection on reset"),
-  E(WSAECONNABORTED, "Software caused connection abort"),
-  E(WSAECONNRESET, "Connection reset by peer"),
-  E(WSAENOBUFS, "No buffer space available"),
-  E(WSAEISCONN, "Socket is already connected"),
-  E(WSAENOTCONN, "Socket is not connected"),
-  E(WSAESHUTDOWN, "Cannot send after socket shutdown"),
-  E(WSAETIMEDOUT, "Connection timed out"),
-  E(WSAECONNREFUSED, "Connection refused"),
-  E(WSAEHOSTDOWN, "Host is down"),
-  E(WSAEHOSTUNREACH, "No route to host"),
-  E(WSAEPROCLIM, "Too many processes"),
+/* destructively remove a trailing line terminator from s */
+static void
+chomp (char *s)
+{
+	size_t len;
+	if (s && (len = strlen (s)) > 0 && s[len - 1] == '\n') {
+		s[--len] = 0;
+		if (len > 0 && s[len - 1] == '\r')
+			s[--len] = 0;
+	}
+}
 
-  /* Yes, some of these start with WSA, not WSAE. No, I don't know why. */
-  E(WSASYSNOTREADY, "Network subsystem is unavailable"),
-  E(WSAVERNOTSUPPORTED, "Winsock.dll out of range"),
-  E(WSANOTINITIALISED, "Successful WSAStartup not yet performed"),
-  E(WSAEDISCON, "Graceful shutdown now in progress"),
-#ifdef WSATYPE_NOT_FOUND
-  E(WSATYPE_NOT_FOUND, "Class type not found"),
-#endif
-  E(WSAHOST_NOT_FOUND, "Host not found"),
-  E(WSATRY_AGAIN, "Nonauthoritative host not found"),
-  E(WSANO_RECOVERY, "This is a nonrecoverable error"),
-  E(WSANO_DATA, "Valid name, no data record of requested type)"),
+/* FormatMessage returns allocated strings, but evutil_socket_error_to_string
+ * is supposed to return a string which is good indefinitely without having
+ * to be freed.  To make this work without leaking memory, we cache the
+ * string the first time FormatMessage is called on a particular error
+ * code, and then return the cached string on subsequent calls with the
+ * same code.  The strings aren't freed until libevent_global_shutdown
+ * (or never).  We use a linked list to cache the errors, because we
+ * only expect there to be a few dozen, and that should be fast enough.
+ */
 
-  /* There are some more error codes whose numeric values are marked
-   * <b>OS dependent</b>. They start with WSA_, apparently for the same
-   * reason that practitioners of some craft traditions deliberately
-   * introduce imperfections into their baskets and rugs "to allow the
-   * evil spirits to escape."  If we catch them, then our binaries
-   * might not report consistent results across versions of Windows.
-   * Thus, I'm going to let them all fall through.
-   */
-  { -1, NULL },
+struct cached_sock_errs_entry {
+	HT_ENTRY(cached_sock_errs_entry) node;
+	DWORD code;
+	char *msg; /* allocated with LocalAlloc; free with LocalFree */
 };
-#undef E
+
+static inline unsigned
+hash_cached_sock_errs(const struct cached_sock_errs_entry *e)
+{
+	/* Use Murmur3's 32-bit finalizer as an integer hash function */
+	DWORD h = e->code;
+	h ^= h >> 16;
+	h *= 0x85ebca6b;
+	h ^= h >> 13;
+	h *= 0xc2b2ae35;
+	h ^= h >> 16;
+	return h;
+}
+
+static inline int
+eq_cached_sock_errs(const struct cached_sock_errs_entry *a,
+		    const struct cached_sock_errs_entry *b)
+{
+	return a->code == b->code;
+}
+
+#ifndef EVENT__DISABLE_THREAD_SUPPORT
+static void *windows_socket_errors_lock_ = NULL;
+#endif
+
+static HT_HEAD(cached_sock_errs_map, cached_sock_errs_entry)
+     windows_socket_errors = HT_INITIALIZER();
+
+HT_PROTOTYPE(cached_sock_errs_map,
+	     cached_sock_errs_entry,
+	     node,
+	     hash_cached_sock_errs,
+	     eq_cached_sock_errs);
+
+HT_GENERATE(cached_sock_errs_map,
+	    cached_sock_errs_entry,
+	    node,
+	    hash_cached_sock_errs,
+	    eq_cached_sock_errs,
+	    0.5,
+	    mm_malloc,
+	    mm_realloc,
+	    mm_free);
+
 /** Equivalent to strerror, but for windows socket errors. */
 const char *
 evutil_socket_error_to_string(int errcode)
 {
-  /* XXXX Is there really no built-in function to do this? */
-  int i;
-  for (i=0; windows_socket_errors[i].code >= 0; ++i) {
-    if (errcode == windows_socket_errors[i].code)
-      return windows_socket_errors[i].msg;
-  }
-  return strerror(errcode);
+	struct cached_sock_errs_entry *errs, *newerr, find;
+	char *msg = NULL;
+
+	EVLOCK_LOCK(windows_socket_errors_lock_, 0);
+
+	find.code = errcode;
+	errs = HT_FIND(cached_sock_errs_map, &windows_socket_errors, &find);
+	if (errs) {
+		msg = errs->msg;
+		goto done;
+	}
+
+	if (0 != FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
+			       FORMAT_MESSAGE_IGNORE_INSERTS |
+			       FORMAT_MESSAGE_ALLOCATE_BUFFER,
+			       NULL, errcode, 0, (LPTSTR)&msg, 0, NULL))
+		chomp (msg);	/* because message has trailing newline */
+	else {
+		size_t len = 50;
+		/* use LocalAlloc because FormatMessage does */
+		msg = LocalAlloc(LMEM_FIXED, len);
+		if (!msg) {
+			msg = "winsock error";
+			goto done;
+		}
+		evutil_snprintf(msg, len, "winsock error 0x%08x", errcode);
+	}
+
+	newerr = (struct cached_sock_errs_entry *)
+		mm_malloc(sizeof (struct cached_sock_errs_entry));
+
+	if (!newerr) {
+		LocalFree(msg);
+		msg = "winsock error";
+		goto done;
+	}
+
+	newerr->code = errcode;
+	newerr->msg = msg;
+	HT_INSERT(cached_sock_errs_map, &windows_socket_errors, newerr);
+
+ done:
+	EVLOCK_UNLOCK(windows_socket_errors_lock_, 0);
+
+	return msg;
 }
+
+#ifndef EVENT__DISABLE_THREAD_SUPPORT
+int
+evutil_global_setup_locks_(const int enable_locks)
+{
+	EVTHREAD_SETUP_GLOBAL_LOCK(windows_socket_errors_lock_, 0);
+	return 0;
+}
+#endif
+
+static void
+evutil_free_sock_err_globals(void)
+{
+	struct cached_sock_errs_entry **errs, *tofree;
+
+	for (errs = HT_START(cached_sock_errs_map, &windows_socket_errors)
+		     ; errs; ) {
+		tofree = *errs;
+		errs = HT_NEXT_RMV(cached_sock_errs_map,
+				   &windows_socket_errors,
+				   errs);
+		LocalFree(tofree->msg);
+		mm_free(tofree);
+	}
+
+	HT_CLEAR(cached_sock_errs_map, &windows_socket_errors);
+
+#ifndef EVENT__DISABLE_THREAD_SUPPORT
+	if (windows_socket_errors_lock_ != NULL) {
+		EVTHREAD_FREE_LOCK(windows_socket_errors_lock_, 0);
+		windows_socket_errors_lock_ = NULL;
+	}
+#endif
+}
+
+#else
+
+#ifndef EVENT__DISABLE_THREAD_SUPPORT
+int
+evutil_global_setup_locks_(const int enable_locks)
+{
+	return 0;
+}
+#endif
+
+static void
+evutil_free_sock_err_globals(void)
+{
+}
+
 #endif
 
 int
@@ -2529,4 +2629,5 @@ void
 evutil_free_globals_(void)
 {
 	evutil_free_secure_rng_globals_();
+	evutil_free_sock_err_globals();
 }

test/Makefile.nmake

@@ -24,11 +24,13 @@ REGRESS_OBJS=regress.obj regress_buffer.obj regress_http.obj regress_dns.obj \
 
 OTHER_OBJS=test-init.obj test-eof.obj test-weof.obj test-time.obj \
 	bench.obj bench_cascade.obj bench_http.obj bench_httpclient.obj \
-	test-changelist.obj
+	test-changelist.obj \
+	print-winsock-errors.obj
 
 PROGRAMS=regress.exe \
 	test-init.exe test-eof.exe test-weof.exe test-time.exe \
-	test-changelist.exe
+	test-changelist.exe \
+	print-winsock-errors.exe
 
 # Disabled for now:
 #	bench.exe bench_cascade.exe bench_http.exe bench_httpclient.exe
@@ -52,6 +54,9 @@ test-weof.exe: test-weof.obj
 test-time.exe: test-time.obj
 	$(CC) $(CFLAGS) $(LIBS) test-time.obj
 
+print-winsock-errors.exe: print-winsock-errors.obj
+	$(CC) $(CFLAGS) $(LIBS) print-winsock-errors.obj
+
 bench.exe: bench.obj
 	$(CC) $(CFLAGS) $(LIBS) bench.obj
 bench_cascade.exe: bench_cascade.obj

test/print-winsock-errors.c

@@ -0,0 +1,84 @@
+#include <winsock2.h>
+#include <windows.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "event2/event.h"
+#include "event2/util.h"
+#include "event2/thread.h"
+
+#define E(x) printf (#x " -> \"%s\"\n", evutil_socket_error_to_string (x));
+
+int main (int argc, char **argv)
+{
+  int i, j;
+  const char *s1, *s2;
+
+  evthread_use_windows_threads ();
+
+  s1 = evutil_socket_error_to_string (WSAEINTR);
+
+  for (i = 0; i < 3; i++) {
+    printf ("\niteration %d:\n\n", i);
+    E(WSAEINTR);
+    E(WSAEACCES);
+    E(WSAEFAULT);
+    E(WSAEINVAL);
+    E(WSAEMFILE);
+    E(WSAEWOULDBLOCK);
+    E(WSAEINPROGRESS);
+    E(WSAEALREADY);
+    E(WSAENOTSOCK);
+    E(WSAEDESTADDRREQ);
+    E(WSAEMSGSIZE);
+    E(WSAEPROTOTYPE);
+    E(WSAENOPROTOOPT);
+    E(WSAEPROTONOSUPPORT);
+    E(WSAESOCKTNOSUPPORT);
+    E(WSAEOPNOTSUPP);
+    E(WSAEPFNOSUPPORT);
+    E(WSAEAFNOSUPPORT);
+    E(WSAEADDRINUSE);
+    E(WSAEADDRNOTAVAIL);
+    E(WSAENETDOWN);
+    E(WSAENETUNREACH);
+    E(WSAENETRESET);
+    E(WSAECONNABORTED);
+    E(WSAECONNRESET);
+    E(WSAENOBUFS);
+    E(WSAEISCONN);
+    E(WSAENOTCONN);
+    E(WSAESHUTDOWN);
+    E(WSAETIMEDOUT);
+    E(WSAECONNREFUSED);
+    E(WSAEHOSTDOWN);
+    E(WSAEHOSTUNREACH);
+    E(WSAEPROCLIM);
+    E(WSASYSNOTREADY);
+    E(WSAVERNOTSUPPORTED);
+    E(WSANOTINITIALISED);
+    E(WSAEDISCON);
+    E(WSATYPE_NOT_FOUND);
+    E(WSAHOST_NOT_FOUND);
+    E(WSATRY_AGAIN);
+    E(WSANO_RECOVERY);
+    E(WSANO_DATA);
+    E(0xdeadbeef); /* test the case where no message is available */
+
+    /* fill up the hash table a bit to make sure it grows properly */
+    for (j = 0; j < 50; j++) {
+      int err;
+      evutil_secure_rng_get_bytes(&err, sizeof(err));
+      evutil_socket_error_to_string(err);
+    }
+  }
+
+  s2 = evutil_socket_error_to_string (WSAEINTR);
+  if (s1 != s2)
+    printf ("caching failed!\n");
+
+  libevent_global_shutdown ();
+
+  return EXIT_SUCCESS;
+}