i#1734 drfuzz: add -fuzz_dump_on_error

Commit log for first patchset:
---------------
i#1734 drfuzz: add -fuzz_dump_on_error

- add -fuzz_dump_on_error option and dump binary data on error reports
---------------

[bruening, 2015-11-18 14:57:57]

Contains a couple of issues, such as adding an interface when a var is already
public and already directly in use.  Should not need another look after
addressing the issues though so LGTM w/ comments

https://codereview.appspot.com/279900043/diff/1/drmemory/drmemory.h
File drmemory/drmemory.h (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/drmemory.h#newcode73
drmemory/drmemory.h:73: extern char logsubdir[MAXIMUM_PATH];
This is already exposed here and used directly in some places: please make all
the uses consistent one way or the other

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c
File drmemory/fuzzer.c (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode395
drmemory/fuzzer.c:395: dr_snprintf(suffix, BUFFER_SIZE_ELEMENTS(suffix),
"error.%d.dat", eid);
This could overflow and then the .dat would be truncated: seems best to either
have a larger buffer or have a printf limit

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode404
drmemory/fuzzer.c:404: ELOG(1, "Fail to create/dump fuzz input to file");
Failed

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode414
drmemory/fuzzer.c:414: "%sfuzz input for ERROR #%d is stored in file %s\n",
Why is "ERROR" in all caps??

https://codereview.appspot.com/279900043/diff/1/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/optionsx.h#newcode623
drmemory/optionsx.h:623: "Dump the current fuzz input on an error report.")
Please elaborate on *where* it's dumped and how the user finds that path

[zhaoqin, 2015-11-18 17:05:45]

https://codereview.appspot.com/279900043/diff/1/drmemory/drmemory.h
File drmemory/drmemory.h (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/drmemory.h#newcode73
drmemory/drmemory.h:73: extern char logsubdir[MAXIMUM_PATH];
On 2015/11/18 14:57:56, bruening wrote:
> This is already exposed here and used directly in some places: please make all
> the uses consistent one way or the other

Done.

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c
File drmemory/fuzzer.c (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode395
drmemory/fuzzer.c:395: dr_snprintf(suffix, BUFFER_SIZE_ELEMENTS(suffix),
"error.%d.dat", eid);
On 2015/11/18 14:57:57, bruening wrote:
> This could overflow and then the .dat would be truncated: seems best to either
> have a larger buffer or have a printf limit

the suffix is 16 bytes, error.*.dat is 10(error..dat) + 1(NULL) + id-size, so it
could hold up to 99999 errors without overflow. Change it to 0x20. should be big
enough.

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode404
drmemory/fuzzer.c:404: ELOG(1, "Fail to create/dump fuzz input to file");
On 2015/11/18 14:57:56, bruening wrote:
> Failed

Done.

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode414
drmemory/fuzzer.c:414: "%sfuzz input for ERROR #%d is stored in file %s\n",
On 2015/11/18 14:57:57, bruening wrote:
> Why is "ERROR" in all caps??

to match the ERROR #1 in the error report, make it non-caps.

https://codereview.appspot.com/279900043/diff/1/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/optionsx.h#newcode623
drmemory/optionsx.h:623: "Dump the current fuzz input on an error report.")
On 2015/11/18 14:57:57, bruening wrote:
> Please elaborate on *where* it's dumped and how the user finds that path

Done.

[bruening, 2015-11-18 21:11:18]

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c
File drmemory/fuzzer.c (right):

https://codereview.appspot.com/279900043/diff/1/drmemory/fuzzer.c#newcode414
drmemory/fuzzer.c:414: "%sfuzz input for ERROR #%d is stored in file %s\n",
On 2015/11/18 17:05:45, zhaoqin wrote:
> On 2015/11/18 14:57:57, bruening wrote:
> > Why is "ERROR" in all caps??
> 
> to match the ERROR #1 in the error report, make it non-caps.

The error report says "Error #1".  It does not say "ERROR #1".