[Bug 993] Fix memory leak when fetching system messages

bk: 479d38605OkXv6yvP-uoYKR0l3BMmg

diff --git a/ports/winnt/libisc/isc_strerror.c b/ports/winnt/libisc/isc_strerror.c
index f9ae72e8c71748aa1327d86573ac38e6b7eafefd..55a72955b0eea101160f4cd130f1573bcdeaed2b 100644 (file)
--- a/ports/winnt/libisc/isc_strerror.c
+++ b/ports/winnt/libisc/isc_strerror.c
@@ -17,9 +17,35 @@
 
 /* From BIND 9 lib/isc/win32/: strerror.c,v 1.5 2002/08/01 03:52:14 mayer */
 
+/*
+ * We don't need this warning message
+ */
+#pragma warning(disable: 4127) /* conditional expression is constant */
+
 #include <stdio.h>
 #include <string.h>
 #include <windows.h>
+#include <isc/list.h>
+
+
+/*
+ * Messsage list
+ */
+typedef struct msg_list msg_list_t;
+
+struct msg_list {
+       int code;
+       char *msg;
+       ISC_LINK(msg_list_t) link;
+};
+
+static ISC_LIST(msg_list_t) errormsg_list;
+
+BOOL initialized = FALSE;
+
+static CRITICAL_SECTION ErrorMsgLock;
+# define LOCK(lock)    EnterCriticalSection(lock)
+# define UNLOCK(lock)  LeaveCriticalSection(lock)
 
 /*
  * Forward declarations
@@ -32,12 +58,24 @@ char *
 GetWSAErrorMessage(int errval);
 
 static char *
-isc__NTstrerror(int err, BOOL *bfreebuf);
+isc__NTstrerror(int err);
+
+/*
+ * Initialize the error message list
+ */
+
+void
+initialize() {
+       ISC_LIST_INIT(errormsg_list);
+       InitializeCriticalSection(&ErrorMsgLock);
+       initialized = TRUE;
+}
 
 char *
 NTstrerror(int errnum) {
-       BOOL bfreebuf;
-       return (isc__NTstrerror(errnum, &bfreebuf));
+       if(!initialized)
+               initialize();
+       return (isc__NTstrerror(errnum));
 }
 /*
  * This routine needs to free up any buffer allocated by FormatMessage
@@ -47,18 +85,15 @@ NTstrerror(int errnum) {
 void
 isc__strerror(int num, char *buf, size_t size) {
        char *msg;
-       BOOL freebuf;
        unsigned int unum = num;
+       if(!initialized)
+               initialize();
 
-       freebuf = FALSE;
-       msg = isc__NTstrerror(num, &freebuf);
+       msg = isc__NTstrerror(num);
        if (msg != NULL)
                _snprintf(buf, size, "%s", msg);
        else
                _snprintf(buf, size, "Unknown error: %u", unum);
-       if(freebuf && msg != NULL) {
-               LocalFree(msg);
-       }
 }
 
 /*
@@ -70,6 +105,29 @@ isc__strerror(int num, char *buf, size_t size) {
 char *
 FormatError(int error) {
        LPVOID lpMsgBuf = NULL;
+
+       msg_list_t *lmsg; 
+
+       /*
+        * See if we already have the error code
+        */
+
+       LOCK(&ErrorMsgLock);
+
+       lmsg = ISC_LIST_HEAD(errormsg_list);
+       while (lmsg != NULL) {
+               if (lmsg->code == error) {
+                       lpMsgBuf = lmsg->msg;
+                       UNLOCK(&ErrorMsgLock);
+                       return (lpMsgBuf);
+               }
+               lmsg = ISC_LIST_NEXT(lmsg, link);
+       }
+
+       /*
+        * Not found
+        */
+
        FormatMessage( 
                FORMAT_MESSAGE_ALLOCATE_BUFFER | 
                FORMAT_MESSAGE_FROM_SYSTEM | 
@@ -82,6 +140,13 @@ FormatError(int error) {
                0,
                NULL); 
 
+       if (lpMsgBuf != NULL) {
+               lmsg = malloc(sizeof(msg_list_t));
+               lmsg->code = error;
+               lmsg->msg = lpMsgBuf;
+               ISC_LIST_APPEND(errormsg_list, lmsg, link);
+       }
+       UNLOCK(&ErrorMsgLock);
        return (lpMsgBuf);
 }
 
@@ -91,14 +156,12 @@ FormatError(int error) {
  * since those messages are not available in the system error messages.
  */
 static char *
-isc__NTstrerror(int err, BOOL *bfreebuf) {
+isc__NTstrerror(int err) {
        char *retmsg = NULL;
 
        /* Copy the error value first in case of other errors */        
        DWORD errval = err; 
 
-       *bfreebuf = FALSE;
-
        /* Get the Winsock2 error messages */
        if (errval >= WSABASEERR && errval <= (WSABASEERR + 1015)) {
                retmsg = GetWSAErrorMessage(errval);
@@ -110,7 +173,6 @@ isc__NTstrerror(int err, BOOL *bfreebuf) {
         * try a system error message
         */
        if (errval > (DWORD) _sys_nerr) {
-               *bfreebuf = TRUE;
                return (FormatError(errval));
        } else {
                return (_sys_errlist[errval]);
@@ -124,14 +186,12 @@ void __cdecl
 NTperror(char *errmsg) {
        /* Copy the error value first in case of other errors */
        int errval = errno; 
-       BOOL bfreebuf = FALSE;
        char *msg;
+       if(!initialized)
+               initialize();
 
-       msg = isc__NTstrerror(errval, &bfreebuf);
+       msg = isc__NTstrerror(errval);
        fprintf(stderr, "%s: %s\n", errmsg, msg);
-       if(bfreebuf == TRUE) {
-               LocalFree(msg);
-       }
 
 }