Re: Fwd: Re: [Meta?] Where do I post proposals/ideas?

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

On 08-01-2015 10:50, Soni L. wrote:
>
>
> On 08/01/15 10:46 AM, Adhemerval Zanella wrote:
>> On 08-01-2015 09:58, Soni L. wrote:
>>> Eh, I forgot to reply to the list...
>>>
>>>
>>> -------- Forwarded Message --------
>>> Subject:     Re: [Meta?] Where do I post proposals/ideas?
>>> Date:     Thu, 08 Jan 2015 09:49:51 -0200
>>> From:     Soni L. <fakedme+libc@gmail.com>
>>> To:     Adhemerval Zanella <azanella@linux.vnet.ibm.com>
>>>
>>>
>>>
>>> On 08/01/15 09:33 AM, Adhemerval Zanella wrote:
>>>> On 08-01-2015 07:06, Soni L. wrote:
>>>>>
>>>>> On 08/01/15 02:13 AM, Paul Pluzhnikov wrote:
>>>>>> On Wed, Jan 7, 2015 at 5:56 PM, Soni L. <fakedme@gmail.com> wrote:
>>>>>>
>>>>>>> This is my proposal/idea:
>>>>>> 1. What actual problem does your proposal solve?
>>>>>> 2. Are you aware of dlmopen ?
>>>>>>
>>>>>
>>>>> Oh great I derped when configuring that gmail alias >.>
>>>>>
>>>>> 1. It solves a problem when loading 2 different <Lua/Python/insert something else> versions where you can't load extensions. For example, if you load Python 2 and Python 3, you can make it so trying to load Python 2 modules works, but then you wouldn't be able to load Python 3 modules, or vice-versa.
>>>>>
>>>>> 2. `man dlmopen`: No manual entry for dlmopen
>>>>>
>>>> dlfcn/dlfcn.h :
>>>>
>>>> #ifdef __USE_GNU
>>>> [...]
>>>> /* Type for namespace indeces.  */
>>>> typedef long int Lmid_t;
>>>>
>>>> /* Special namespace ID values.  */
>>>> # define LM_ID_BASE     0       /* Initial namespace.  */
>>>> # define LM_ID_NEWLM    -1      /* For dlmopen: request new namespace.  */
>>>> [...]
>>>> /* Like `dlopen', but request object to be allocated in a new namespace.  */
>>>> extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROWNL;
>>>>
>>>> /* Find the run-time address in the shared object HANDLE refers to
>>>>      of the symbol called NAME with VERSION.  */
>>>> extern void *dlvsym (void *__restrict __handle,
>>>>                        const char *__restrict __name,
>>>>                        const char *__restrict __version)
>>>>        __THROW __nonnull ((2, 3));
>>>> #endif
>>>>
>>>
>>> Oh... And how do I use it?
>>>
>>>
>>>
>> $ cat dlmopen_test.c
>> #define _GNU_SOURCE
>>
>> #include <dlfcn.h>
>> #include <link.h>
>> #include <stdio.h>
>> #include <stdlib.h>
>>
>> typedef void (*foo_t)(void);
>>
>> int
>> main (int argc, char **argv)
>> {
>>    const char lib_string[] = "dummy.so.1";
>>
>>    void *handle1 = dlmopen (LM_ID_NEWLM, lib_string, RTLD_LOCAL | RTLD_LAZY);
>>    if (handle1 == NULL)
>>      {
>>        printf ("error: dlmopen failed (1)\n");
>>        exit (EXIT_FAILURE);
>>      }
>>    printf ("handle1 = 0x%p\n", handle1);
>>
>>    void *handle2 = dlmopen (LM_ID_NEWLM, lib_string, RTLD_LOCAL | RTLD_LAZY);
>>    if (handle1 == NULL)
>>      {
>>        printf ("error: dlmopen failed (2)\n");
>>        exit (EXIT_FAILURE);
>>      }
>>    printf ("handle1 = 0x%p\n", handle2);
>>
>>    foo_t foo1 = (foo_t) dlsym (handle1, "foo");
>>    if (foo1 == NULL)
>>      {
>>        printf ("error: dlvsym failed (1)\n");
>>        exit (EXIT_FAILURE);
>>      }
>>    foo_t foo2 = (foo_t) dlsym (handle1, "foo");
>>    if (foo1 == NULL)
>>      {
>>        printf ("error: dlvsym failed (2)\n");
>>        exit (EXIT_FAILURE);
>>      }
>>
>>    foo1 ();
>>    foo2 ();
>>
>>    dlclose (handle1);
>>    dlclose (handle2);
>>
>>    return 0;
>> }
>>
>> $ cat dummy.c
>> #include <stdio.h>
>>
>> void foo(void)
>> {
>>    printf ("foo\n");
>> }
>>
>> $ cat Makefile
>> CC=gcc
>> CFLAGS = -g -Wall
>>
>> all: dlmopen_test
>>
>> dlmopen_test: dlmopen_test.c dummy.so.1
>>     $(CC) $< $(CFLAGS) -ldl -o $@
>>
>> dummy.so.1: dummy.o
>>     $(CC) $< $(CFLAGS) -shared -o $@
>>
>> dummy.o: dummy.c
>>     $(CC) $< $(CFLAGS) -fPIC -c -o $@
>>
>> .PHONY: clean
>>
>> clean:
>>     rm -f dlmopen_test *.o dummy.so.1
>>
>> $ make
>> gcc dummy.c -g -Wall -fPIC -c -o dummy.o
>> gcc dummy.o -g -Wall -shared -o dummy.so.1
>> gcc dlmopen_test.c -g -Wall -ldl -o dlmopen_test
>>
>> $ LD_LIBRARY_PATH=. ./dlmopen_test
>> handle1 = 0x0xd12030
>> handle1 = 0x0xd132b0
>> foo
>> foo
>>
>
> And if I want dummy.c/dummy.so to open more .so's?
>
I can't see why not, I never tried thou.