Re: [libvirt] [PATCH] Fix cd eject segfault

[Cole Robinson <crobinso@xxxxxxxxxx>]

Daniel P. Berrange wrote:
> On Thu, Aug 21, 2008 at 11:20:28PM -0400, Cole Robinson wrote:
>   
>> The cdrom eject code was trying to dereference the
>> NULL source of an empty cdrom. Attached patch fixes
>> this.
>> @@ -2972,6 +2973,13 @@ static int qemudDomainChangeCDROM(virDomainPtr dom,
>>          }
>>          VIR_FREE(safe_path);
>>  
>> +        newsrc = strdup(newdisk->src);
>> +        if (!newsrc) {
>> +            qemudReportError(dom->conn, dom, NULL, VIR_ERR_OPERATION_FAILED,
>> +                             "%s", _("out of memory"));
>> +            return -1;
>> +        }
>>     
>
> Rather than dup'ing the string here and having to deal with OOM...
>
>   
>> +
>>      } else if (asprintf(&cmd, "eject cdrom") == -1) {
>>          qemudReportError(dom->conn, dom, NULL, VIR_ERR_OPERATION_FAILED,
>>                           "%s", _("out of memory"));
>> @@ -2982,11 +2990,17 @@ static int qemudDomainChangeCDROM(virDomainPtr dom,
>>          qemudReportError(dom->conn, dom, NULL, VIR_ERR_OPERATION_FAILED,
>>                           "%s", _("cannot change cdrom media"));
>>          VIR_FREE(cmd);
>> +        VIR_FREE(newsrc);
>>          return -1;
>>      }
>>      VIR_FREE(reply);
>>      VIR_FREE(cmd);
>> -    strcpy(olddisk->src, newdisk->src);
>> +
>> +    VIR_FREE(olddisk->src);
>> +    if (newsrc) {
>> +        olddisk->src = newsrc;
>> +        newsrc = NULL;
>> +    }
>>     
>
> Just do
>
>       VIR_FREE(olddisk->src);
>       olddisk->src = newdisk->src;
>       newdisk->src = NULL;
>
> Daniel
>   

Whoops, yeah. I certainly over complicated that.

Updated patch attached.

Thanks,
Cole

diff --git a/src/qemu_driver.c b/src/qemu_driver.c
index 06fbe55..21fd468 100644
--- a/src/qemu_driver.c
+++ b/src/qemu_driver.c
@@ -2986,7 +2986,10 @@ static int qemudDomainChangeCDROM(virDomainPtr dom,
     }
     VIR_FREE(reply);
     VIR_FREE(cmd);
-    strcpy(olddisk->src, newdisk->src);
+
+    VIR_FREE(olddisk->src);
+    olddisk->src = newdisk->src;
+    newdisk->src = NULL;
     olddisk->type = newdisk->type;
     return 0;
 }

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