RFR: 8230466: check malloc/calloc results in jdk.hotspot.agent

[Baesken, Matthias]

Hello  Yasumasa and Chris, thanks for your input .
Here is a new  webrev  , without  the unneeded  memset-calls  after calloc .

http://cr.openjdk.java.net/~mbaesken/webrevs/8230466.1/

Hope everyone is happy with this now �� !

Best regards, Matthias


> Hi Matthias,
> 
> src/jdk.hotspot.agent/linux/native/libsaproc/symtab.c:
> ```
>   405       // guarantee(symtab == NULL, "multiple symtab");
>   406       symtab = (struct symtab*)calloc(1, sizeof(struct symtab));
>   407       if (symtab == NULL) {
>   408          goto quit;
>   409       }
>   410       memset(symtab, 0, sizeof(struct symtab));
> ```
> 
> Why do you call memset() to clear symtab in L410?
> symtab is allocated via calloc() in L406, so symtab would already cleared.
> 
> 
> Thanks,
> 
> Yasumasa (ysuenaga)
> 
> 
> On 2019/09/03 18:14, David Holmes wrote:
> > Hi Matthias,
> >
> > Re-directing to serviceability-dev.
> >
> > David
> >
> > On 3/09/2019 5:42 pm, Baesken, Matthias wrote:
> >> Hello, please review the following small fix .
> >>
> >> In   jdk.hotspot.agent  native code (linux / macosx)   we miss to check the
> result of malloc/calloc a few times .
> >> This should be  adjusted.
> >> Additionally  I added initialization  to the symtab  array  in  symtab.c   (by
> calling memset  to make sure we have a defined state )  .
> >>
> >>
> >>
> >> One question (was not really sure about this one so I did not change it so
> far) :
> >>
> >>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8230466.0/src/jdk.hotspot.
> agent/macosx/native/libsaproc/symtab.c.frames.html
> >>
> >> 359 void destroy_symtab(symtab_t* symtab) {
> >> 360   if (!symtab) return;
> >> 361   free(symtab->strs);
> >> 362   free(symtab->symbols);
> >> 363   free(symtab);
> >> 364 }
> >>
> >>
> >>
> >> Here we miss to close   symtab->hash_table   (opened by  dbopen) ,  is it
> needed  (haven't  used dbopen much - maybe someone can comment on
> this)?
> >>
> >>
> >> bug/webrev :
> >>
> >> https://bugs.openjdk.java.net/browse/JDK-8230466
> >>
> >> http://cr.openjdk.java.net/~mbaesken/webrevs/8230466.0/
> >>
> >>
> >> Thanks and best regards, Matthias
> >>