Issues in utmp/utmpx headers

[David Lee]

Sorry I am totally unfamiliar with Cygwin internals, here are some
related questions:

1. how does one test a code path that involves a failed syscall
(strdup() in this case, but can be others) in cygwin dll?

2. If the call to strdup() fails, I want to debug_print() the errno
value set by strdup(). Do I have to save errno before debug_print()
that and restore afterwards?

3. Does the instruction from 6.21 in

   https://cygwin.com/faq/faq.html#faq.prog5asdramming.building-cygwin

   generates a debugging dll (i.e. contains debug symbols usable by
gdb)? If not, what modifications are needed to create one?

Thanks.

On 29 December 2015 at 13:16, Brian Inglis
<Brian.Inglis@systematicsw.ab.ca> wrote:
>> > David Lee <mailtolky <at> gmail.com> writes:
>> >> While trying to port bsdgames to Cygwin I spotted the following issues:
>> >> (1) In /usr/include/utmpx.h, utmpxname() is declared a void function.
>> >> Should it return int?
>> >> (2) In /usr/include/sys/utmp.h, utmpname() is declared a void
>> >> function. Should it return int?
>> >> (3) _PATH_UTMPX is not defined in any system headers.
>
>> On 28 December 2015 at 03:02, Brian Inglis
>> <Brian.Inglis <at> systematicsw.ab.ca> wrote:
>> > Search packages for missing files e.g.
>> > https://cygwin.com/cgi-bin2/package-grep.cgi?grep=utmp.h&arch=x86_64
>> > brings up package cygwin-devel and cygwin32.
>> > Download and run setup and select cygwin-devel to install the headers and
>> > libraries.
>
> David Lee <mailtolky <at> gmail.com> writes:
>> The issue isn't missing, not-installed packages. The issues are (1)
>> some function declaration seem wrong; and (2) a constant is missing.
>
> Pardon my reading comprehension bork!
>
> The utmpname implementation in newlib-cygwin/winsup/cygwin/syscalls.cc
> could probably be improved to: avoid a memory leak; return -1 if
> strdup fails, zero otherwise; default the path if a null pointer or string
> argument is passed.
> That would also fix utmpxname which is an alias.
> Such a change would have little likely impact on downstream apps, but could
> produce warnings about ignoring return values.
>
> Unfortunately there appears to be no standard defined names to access the
> default file name although GNU and Cygwin provide UTMP_FILE and UTMPX_FILE;
> GNU also provide UTMP_FILENAME and UTMPX_FILENAME.
> _PATH_UTMP and _PATH_UTMPX are implementation reserved names which may or
> may not be provided, though adding the latter in paths.h would be trivial.
>
> As the developers say, patches always welcome.
>
>
>
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