[v3,2/5] Get rid of "gdb_dirbuf" and use "getcwd (NULL, 0)"

  Currently we have "current_directory" and "gdb_dirbuf" globals, which
means that we basically have two possible places to consult when we
want to know GDB's current working directory.

This is not ideal and can lead to confusion.  Moreover, the way we're
using "gdb_difbuf" along with "getcwd" is problematic because we
declare the buffer with "1024" elements hardcoded, which does not take
into account longer pathnames that are possible in many filesystems.
Using "PATH_MAX" would also not be a solution because of portability
problems.  Therefore, the best solution is to rely on the fact that
"getcwd (NULL, 0)" will "do the right thing" and return a
heap-allocated string containing the full path.  With the new "getcwd"
module from gnulib, it is now possible to do that without worrying
about breaking some host.

With this patch "current_directory" is now the only place to check for
GDB's cwd.

gdb/ChangeLog:
yyyy-mm-dd  Sergio Durigan Junior  <sergiodj@redhat.com>

	* cli/cli-cmds.c (pwd_command): Use "getcwd (NULL, 0)".
	(cd_command): Likewise.  Free "current_directory" before
	assigning to it.
	* main.c (captured_main_1): Use "getcwd (NULL, 0)".
	* mi/mi-cmd-env.c (mi_cmd_env_pwd): Likewise.
	* top.c (gdb_dirbuf): Remove global declaration.
	* top.h (gdb_dirbuf): Likewise.
---
 gdb/cli/cli-cmds.c  | 17 ++++++++++++-----
 gdb/main.c          |  5 ++---
 gdb/mi/mi-cmd-env.c |  8 ++++----
 gdb/top.c           |  3 ---
 gdb/top.h           |  1 -
 5 files changed, 18 insertions(+), 16 deletions(-)
  

On 09/21/2017 11:59 PM, Sergio Durigan Junior wrote:
> 
> gdb/ChangeLog:
> yyyy-mm-dd  Sergio Durigan Junior  <sergiodj@redhat.com>
> 
> 	* cli/cli-cmds.c (pwd_command): Use "getcwd (NULL, 0)".
> 	(cd_command): Likewise.  Free "current_directory" before
> 	assigning to it.
> 	* main.c (captured_main_1): Use "getcwd (NULL, 0)".
> 	* mi/mi-cmd-env.c (mi_cmd_env_pwd): Likewise.
> 	* top.c (gdb_dirbuf): Remove global declaration.
> 	* top.h (gdb_dirbuf): Likewise.

OK.  And trying the new thing:

Reviewed-by: Pedro Alves <palves@redhat.com>

... provided the nit below is addressed.

You can push patches 1 and 2 now, without waiting for the
rest of the series.

> diff --git a/gdb/mi/mi-cmd-env.c b/gdb/mi/mi-cmd-env.c
> index 977b6e274d..db87ead33d 100644
> --- a/gdb/mi/mi-cmd-env.c
> +++ b/gdb/mi/mi-cmd-env.c
> @@ -73,12 +73,12 @@ mi_cmd_env_pwd (const char *command, char **argv, int argc)
>      }
>       
>    /* Otherwise the mi level is 2 or higher.  */
> -
> -  if (! getcwd (gdb_dirbuf, sizeof (gdb_dirbuf)))

Please leave the empty line after the comment.  That comment is
logically related to the code above, not the getcwd call.

> +  gdb::unique_xmalloc_ptr<char> cwd (getcwd (NULL, 0));
> +  if (cwd == NULL)
>      error (_("-environment-pwd: error finding name of working directory: %s"),
>             safe_strerror (errno));
> -    
> -  uiout->field_string ("cwd", gdb_dirbuf);
> +
> +  uiout->field_string ("cwd", cwd.get ());
>  }

Thanks,
Pedro Alves
  

On Friday, September 22 2017, Pedro Alves wrote:

> On 09/21/2017 11:59 PM, Sergio Durigan Junior wrote:
>> 
>> gdb/ChangeLog:
>> yyyy-mm-dd  Sergio Durigan Junior  <sergiodj@redhat.com>
>> 
>> 	* cli/cli-cmds.c (pwd_command): Use "getcwd (NULL, 0)".
>> 	(cd_command): Likewise.  Free "current_directory" before
>> 	assigning to it.
>> 	* main.c (captured_main_1): Use "getcwd (NULL, 0)".
>> 	* mi/mi-cmd-env.c (mi_cmd_env_pwd): Likewise.
>> 	* top.c (gdb_dirbuf): Remove global declaration.
>> 	* top.h (gdb_dirbuf): Likewise.
>
> OK.  And trying the new thing:
>
> Reviewed-by: Pedro Alves <palves@redhat.com>
>
> ... provided the nit below is addressed.

AFAIU I had to add this to the commit log.  I did this; if this wasn't
correct, I apologize.

>> diff --git a/gdb/mi/mi-cmd-env.c b/gdb/mi/mi-cmd-env.c
>> index 977b6e274d..db87ead33d 100644
>> --- a/gdb/mi/mi-cmd-env.c
>> +++ b/gdb/mi/mi-cmd-env.c
>> @@ -73,12 +73,12 @@ mi_cmd_env_pwd (const char *command, char **argv, int argc)
>>      }
>>       
>>    /* Otherwise the mi level is 2 or higher.  */
>> -
>> -  if (! getcwd (gdb_dirbuf, sizeof (gdb_dirbuf)))
>
> Please leave the empty line after the comment.  That comment is
> logically related to the code above, not the getcwd call.

Done.

>> +  gdb::unique_xmalloc_ptr<char> cwd (getcwd (NULL, 0));
>> +  if (cwd == NULL)
>>      error (_("-environment-pwd: error finding name of working directory: %s"),
>>             safe_strerror (errno));
>> -    
>> -  uiout->field_string ("cwd", gdb_dirbuf);
>> +
>> +  uiout->field_string ("cwd", cwd.get ());
>>  }
>
> Thanks,
> Pedro Alves

Pushed.

43573013c9836f2b91b74b9b29dac35fdb41e06b

Thanks,