Re: [PATCH] Disable get_ptrace_pid for NetBSD

Kamil Rytarowski
2020-03-18T21:41:48Z

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On 18.03.2020 22:15, Simon Marchi wrote:
> On 2020-03-18 12:29 p.m., Kamil Rytarowski wrote:
>> Unlike most other Operating Systems, NetBSD tracks both pid and lwp.
>> The process id on NetBSD is stored always in the pid field of ptid.
>>
>> gdb/ChangeLog:
>>
>> * inf-ptrace.h: Disable get_ptrace_pid on NetBSD.
>> * inf-ptrace.c: Likewise.
>> * (inf_ptrace_target::resume): Update.
>> * (inf_ptrace_target::xfer_partial): Likewise.
>> ---
>> gdb/ChangeLog | 7 +++++++
>> gdb/inf-ptrace.c | 19 +++++++++++++++++--
>> gdb/inf-ptrace.h | 2 ++
>> 3 files changed, 26 insertions(+), 2 deletions(-)
>>
>> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
>> index 84964dc00ac..36e333ec8ba 100644
>> --- a/gdb/ChangeLog
>> +++ b/gdb/ChangeLog
>> @@ -1,3 +1,10 @@
>> +2020-03-18 Kamil Rytarowski <n54@gmx.com>
>> +
>> + * inf-ptrace.h: Disable get_ptrace_pid on NetBSD.
>> + * inf-ptrace.c: Likewise.
>> + * (inf_ptrace_target::resume): Update.
>> + * (inf_ptrace_target::xfer_partial): Likewise.
>> +
>> 2020-03-17 Kamil Rytarowski <n54@gmx.com>
>>
>> * regformats/regdef.h: Put reg in gdb namespace.
>> diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
>> index db17a76d946..e8bf66ed45f 100644
>> --- a/gdb/inf-ptrace.c
>> +++ b/gdb/inf-ptrace.c
>> @@ -313,8 +313,12 @@ inf_ptrace_target::kill ()
>> target_mourn_inferior (inferior_ptid);
>> }
>>
>> +#ifndef __NetBSD__
>> /* Return which PID to pass to ptrace in order to observe/control the
>> - tracee identified by PTID. */
>> + tracee identified by PTID.
>> +
>> + Unlike most other Operating Systems, NetBSD tracks both pid and lwp
>> + and avoids this function. */
>>
>> pid_t
>> get_ptrace_pid (ptid_t ptid)
>> @@ -328,6 +332,7 @@ get_ptrace_pid (ptid_t ptid)
>> pid = ptid.pid ();
>> return pid;
>> }
>> +#endif
>>
>> /* Resume execution of thread PTID, or all threads if PTID is -1. If
>> STEP is nonzero, single-step it. If SIGNAL is nonzero, give it
>> @@ -344,7 +349,13 @@ inf_ptrace_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
>> single-threaded processes, so simply resume the inferior. */
>> pid = inferior_ptid.pid ();
>> else
>> - pid = get_ptrace_pid (ptid);
>> + {
>> +#ifdef __NetBSD__
>> + pid = ptid. pid();
>> +#else
>> + pid = get_ptrace_pid (ptid);
>> +#endif
>> + }
>
> To avoid the ifdefs in this more complex code, can't you use a gdb_ptrace function like in
> the other patches? This time, it would look like:
>
> static int
> gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr,
> PTRACE_TYPE_ARG4 data)
> {
> #ifdef __NetBSD__
> return ptrace (request, ptid.pid (), addr, data);
> #else
> pid_t pid = get_ptrace_pid (ptid);
> return ptrace (request, pid, addr, data);
> #endif
> }
>
> Simon
>

I will go for it, but only for a selection of ptrace () calls in this file.

In certain places there would need to be need to compose ptid_t out of
plain pid. Another case is PT_TRACE_ME.

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