RFR: JDK-8007606 (original) (raw)

Vitaly Davidovich vitalyd at gmail.com
Tue Feb 5 16:33:53 PST 2013

Hi John,

In NetworkInterface.c:

162 ret = (MIB_IFROW *) malloc(sizeof(MIB_IFROW)); 163 if(ret == NULL) 164 return NULL;

tableP is left dangling if line 164 runs, no?

222 if (ret != NO_ERROR) { 223 if (tableP != NULL) { 224 free(tableP);

225 JNU_ThrowByName(env, "java/lang/Error", 226 "IP Helper Library GetIfTable function failed"); 227 JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure"); 228 return -1; 229 }

How do you know it's an OOM here?

289 curr = (netif *)calloc(1, sizeof(netif)); 290 if (curr != NULL) { 291 wlen = MultiByteToWideChar(CP_OEMCP, 0, ifrowP->bDescr, 292 ifrowP->dwDescrLen, NULL, 0); 293 if(wlen == 0) { 294 // MultiByteToWideChar should not fail 295 // But in rare case it fails, we allow 'char' to be displayed 296 curr->displayName = (char *)malloc(ifrowP->dwDescrLen + 1); 297 if(curr->displayName == NULL) 298 return -1; 299 300 } else { 301 curr->displayName = (char )malloc(wlen(sizeof(wchar_t))+1); 302 if(curr->displayName == NULL) 303 return -1; 304 }

Before returning, doesn't curr itself need to be freed? Same thing in this block:

308 if (curr->name == NULL || curr->displayName == NULL) { 309 if (curr->name) free(curr->name); 310 if (curr->displayName) free(curr->displayName); 311 curr = NULL; 312 }

In NetworkInterface_winXP.c:

154 if(ret == NULL) { 155 JNU_ThrowByName(env, "java/lang/OutOfMemoryError", 0); 156 return NULL; 157 }

adapterInfo needs free here?

I also noticed some ptrs are compared against NULL while others against 0 - why the inconsistency?

Also, might it be cleaner to use multiple chained goto's to handle cleanup in functions with multiple allocations? The early returns in some of these places are a recipe for leaks I think. I'm thinking something like:

r1 = malloc(...); if (r1 == NULL) goto out1;

r2 = malloc(...); if (r2 == NULL) goto out2;

out2: free(r2); out1: free(r1);

Thanks

Sent from my phone On Feb 5, 2013 6:42 PM, "John Zavgren" <john.zavgren at oracle.com> wrote:

Greetings: I modified the use of malloc() and realloc() so that return values are checked and potential memory leaks and data corruption problems are prevented.

http://cr.openjdk.java.net/~jzavgren/8007606/webrev.01/ Thanks! John Zavgren -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mail.openjdk.java.net/pipermail/net-dev/attachments/20130205/2d62f857/attachment.html

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