RFR JDK-8007609

[Chris Hegarty]

Apologies, you are correct. I'll book an appointment with the optician!

-Chris.

On 08/02/2013 00:15, David Holmes wrote:
> On 7/02/2013 10:54 PM, Chris Hegarty wrote:
>> On 02/07/2013 11:54 AM, David Holmes wrote:
>>> ....
>>>> AFAICS setting len=0 means len==0 will be true and so we will
>>>> free(result).
>>>
>>> And if len != 0 then we will have already freed result, so avoiding a
>>> double-free.
>>
>> Here's the code as it stands today.
>
> Yes .... I don't see the problem
>
>>
>> 113 result = (WCHAR*)malloc(MAX_PATH * sizeof(WCHAR));
>> 114 if (result != NULL) {
>
> we've entered this block so we must free result evetually.
>
>> 115 DWORD len = (*GetFinalPathNameByHandle_func)(h, result, MAX_PATH, 0);
>> 116 if (len >= MAX_PATH) {
>> 117 /* retry with a buffer of the right size */
>> 118 result = (WCHAR*)realloc(result, (len+1) * sizeof(WCHAR));
>> 119 if (result != NULL) {
>> 120 len = (*GetFinalPathNameByHandle_func)(h, result, len, 0);
>> 121 } else {
>> 122 len = 0;
>> 123 }
>> 124 }
>> 125 if (len > 0) {
>
> len was good so we've gone this path
>
>> 126 /**
>> 127 * Strip prefix (should be \\?\ or \\?\UNC)
>> 128 */
>> 129 if (result[0] == L'\\' && result[1] == L'\\' &&
>> 130 result[2] == L'?' && result[3] == L'\\')
>> 131 {
>> 132 int isUnc = (result[4] == L'U' &&
>> 133 result[5] == L'N' &&
>> 134 result[6] == L'C');
>> 135 int prefixLen = (isUnc) ? 7 : 4;
>> 136 /* actual result length (includes terminator) */
>> 137 int resultLen = len - prefixLen + (isUnc ? 1 : 0) + 1;
>> 138
>> 139 /* copy result without prefix into new buffer */
>> 140 WCHAR *tmp = (WCHAR*)malloc(resultLen * sizeof(WCHAR));
>> 141 if (tmp == NULL) {
>> 142 len = 0; <<<<<<<<<<<<<<<<<<< HERE
>
> malloc failed so we need to bail out. We will now skip to line 161
>
>> 143 } else {
>> 144 WCHAR *p = result;
>> 145 p += prefixLen;
>> 146 if (isUnc) {
>> 147 WCHAR *p2 = tmp;
>> 148 p2[0] = L'\\';
>> 149 p2++;
>> 150 wcscpy(p2, p);
>> 151 } else {
>> 152 wcscpy(tmp, p);
>> 153 }
>> 154 free(result);
>> 155 result = tmp;
>> 156 }
>> 157 }
>> 158 }
>> 159
>> 160 /* unable to get final path */
>> 161 if (len == 0 && result != NULL) {
>
> We reach here because len==0 and result != NULL
>
>> 162 free(result);
>> 163 result = NULL;
>> 164 }
>> 165 }
>
> Looks fine to me.
> David
>
>> -Chris.