Using tar to access files

[Chris Johns]

On 14/07/2015 1:57 am, Gedare Bloom wrote:
> On Mon, Jul 13, 2015 at 11:26 AM, Pavel Pisa <pisa at cmp.felk.cvut.cz> wrote:
>> Hello Sujay Raj,
>>
>>
>> On Tuesday 30 of June 2015 06:39:28 Sujay Raj wrote:
>>> I need to access configurations files the for web server I am porting to
>>> rtems.
>>>
>>> I create a tar archive , that contains the required folders and files ,
>>> convert it into c source using rtems-bin2c , ( a header file and a c source
>>> ) and link them with my project.
>>>
>>> In the init, I call
>>>
>>> sc = Untar_FromMemory((void *)TARFILE_START, (size_t)TARFILE_SIZE);
>>>
>>> where TARFILE_START is the macro with the name of the array , TARFILE_SIZE
>>> is the size of the array.
>>>
>>> But when I run the program, I get errors of the form
>>>
>>> "Untar: failed to create file <folder>/<filename>"
>>>
>>
>> I have noticed and reported similar problem and workaround some
>> time ago. Problem is, that Untar_FromMemory() function fails
>> when it reaches a directory entry in a TAR file and given
>> directory already exists. It fails even for existing
>> top level directory which has to exists in RTEMS runing
>> system and are packed by TAR by default.
>>
>> My fix is not ideal. Other (more generic option) is to use
>> stat(const char *path, struct stat *buf) with check
>> that target is already existing direcory. But using stat()
>> in really minimal application can lead to unneeded overhead.
>> Other option is to ignore directory create errors completelly
>> but I do not like something like that in RT system.
>>
>> There is alternative way to untar file by other RTEMS functions
>> but we use Untar_FromMemory() in more projects. If there is no
>> objection or opinion for other solution, I prepare and check
>> patch with stat().
>>
>>
>> From 4ce027b21cfde5bc6143d51d244345e05dd85cd4 Mon Sep 17 00:00:00 2001
>> Message-Id: <4ce027b21cfde5bc6143d51d244345e05dd85cd4.1436800331.git.ppisa at pikron.com>
>> From: Pavel Pisa <ppisa at pikron.com>
>> Date: Mon, 31 Mar 2014 00:57:12 +0200
>> Subject: [PATCH] untar: workaround for fail on top level directory existence.
>> To: rtems-devel at rtems.org
>>
>> Signed-off-by: Pavel Pisa <ppisa at pikron.com>
>> ---
>>  cpukit/libmisc/untar/untar.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/cpukit/libmisc/untar/untar.c b/cpukit/libmisc/untar/untar.c
>> index aed8fed..498fa12 100644
>> --- a/cpukit/libmisc/untar/untar.c
>> +++ b/cpukit/libmisc/untar/untar.c
>> @@ -203,6 +203,8 @@ Untar_FromMemory(
>>        }
>>      } else if (linkflag == DIRTYPE) {
>>        if ( mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO) != 0 ) {
>> +        if ( !strcmp(fname, "/") || !strcmp(fname, "./"))
>> +          continue;
> So this just proceeds if the top-level directly already exists? I
> don't really have a problem with the patch if there is a test case
> that shows the problem case, but I think the reported failure may be
> elsewhere since Sujay said the error was "Untar: failed to create
> file" and not "directory".

Is this related to https://devel.rtems.org/ticket/2207 ?

Chris

> 
>>          printk("Untar: failed to create directory %s\n", fname);
>>          retval = UNTAR_FAIL;
>>          break;
>> --
>> 1.9.1
>> _______________________________________________
>> devel mailing list
>> devel at rtems.org
>> http://lists.rtems.org/mailman/listinfo/devel
> _______________________________________________
> devel mailing list
> devel at rtems.org
> http://lists.rtems.org/mailman/listinfo/devel
>