Re: [RFA 3/5 v2] Darwin: set startup-with-shell to off on Sierra and later.

[Xavier Roirand <roirand@adacore.com>]

Le 9/9/18 à 1:04 PM, Simon Marchi a écrit :
> Thanks for the update!
> 
> CCing Tom, because he had a similar patch that was unfortunately not 
> looked at yet... so maybe he has an opinion about this.
> 
> On 2018-09-09 11:17, Xavier Roirand wrote:
>> On Mac OS X Sierra and later, the shell is not allowed to be
>> debug so add a check and disable startup with shell in that
>> case. This disabling is done temporary before forking
>> inferior and restored after the fork.
>>
>> gdb/ChangeLog:
>>
>>         * darwin-nat.c (should_disable_startup_with_shell):
>>         New function.
>>         (darwin_nat_target::create_inferior): Add call.
>>
>> Change-Id: Ie4d9090f65fdf2e83ecf7a0f9d0647fb1c27cdcc
>> ---
>>  gdb/darwin-nat.c | 32 ++++++++++++++++++++++++++++++++
>>  1 file changed, 32 insertions(+)
>>
>> diff --git a/gdb/darwin-nat.c b/gdb/darwin-nat.c
>> index be80163d22e..d23706d79fd 100644
>> --- a/gdb/darwin-nat.c
>> +++ b/gdb/darwin-nat.c
>> @@ -1854,15 +1854,47 @@ darwin_execvp (const char *file, char * const
>> argv[], char * const env[])
>>    posix_spawnp (NULL, argv[0], NULL, &attr, argv, env);
>>  }
>>
>> +/* Read kernel version, and return false on Sierra or later.  */
> 
> I think this is the other way around (return trun on Sierra or later).
> 
>> +
>> +static int
>> +should_disable_startup_with_shell ()
>> +{
>> +  char str[16];
>> +  size_t sz = sizeof (str);
>> +  int ret;
>> +
>> +  ret = sysctlbyname ("kern.osrelease", str, &sz, NULL, 0);
>> +  if (ret == 0 && sz < sizeof (str))
>> +    {
>> +      unsigned long ver = strtoul (str, NULL, 10);
>> +      if (ver >= 16)
>> +        return TRUE;
>> +    }
>> +  return FALSE;
>> +}
>> +
>>  void
>>  darwin_nat_target::create_inferior (const char *exec_file,
>>                      const std::string &allargs,
>>                      char **env, int from_tty)
>>  {
>> +  gdb::optional<scoped_restore_tmpl<int>> restore_startup_with_shell;
>> +  int startup_shell_disabled = 0;
>> +
>> +  if (startup_with_shell && should_disable_startup_with_shell ())
>> +    {
>> +      warning (_("startup-with-shell not supported on this macOS
>> version, disabling it."));
>> +      restore_startup_with_shell.emplace (&startup_with_shell, 0);
>> +      startup_shell_disabled = 1;
>> +    }
>> +
>>    /* Do the hard work.  */
>>    fork_inferior (exec_file, allargs, env, darwin_ptrace_me,
>>           darwin_ptrace_him, darwin_pre_ptrace, NULL,
>>           darwin_execvp);
>> +
>> +  if (startup_shell_disabled)
>> +    restore_startup_with_shell.emplace (&startup_with_shell, 1);
> 
> You shouldn't need this last bit, nor the startup_shell_disabled 
> variable.  When it gets destroyed, the restore_startup_with_shell object 
> takes care of restoring the value of the startup_with_shell variable to 
> the value it had when it was constructed (the first emplace call).
> 
> In other words, this call:
> 
>    restore_startup_with_shell.emplace (&startup_with_shell, 0);
> 
> means "save the current value of startup_with_shell, then put 0 in it".
> 
> When the destructor of restore_startup_with_shell is called, it restores 
> the saved value.
> 
> With that fixed, it would LGTM, although I did not try it because I 
> don't have access to a Mac at the moment.
> 
> Simon

Thanks, I'll fix this.