Re: [PATCH 2/2] dlfcn,elf: implement dlmem() function [BZ #11767]

[stsp <stsp2@yandex.ru>]

13.02.2023 18:45, Florian Weimer пишет:
> On the Google branches, there is somewhat similar functionality, in the
> form of dlopen_with_offset.

I'll list dlopen_with_offset() below.


> Your patch seems to allow the creation of fully unnamed link maps
> (especially if the shared object being loaded does not come with
> DT_SONAME).  I think we need to discuss the consequences of that.  This
> feature could be independently useful to some applications, to the
> extent that they would use dlmem just for that purposes (even for files
> that are stored on disk).

Probably, but in v9 I added a possibility
to specify an object name for dlmem().
It also has an fdlopen() impl as a test-case.

So dlopen_with_offset():

static void *
dlopen_with_offset (int fd, int flags, off_t offset)
{
   off_t len;
   void *addr;
   void *handle;

   len = lseek (fd, 0, SEEK_END);
   lseek (fd, 0, SEEK_SET);
   if (len <= offset)
     return NULL;
   len -= offset;
   addr = mmap (NULL, len, PROT_READ, MAP_PRIVATE, fd, offset);
   if (addr == MAP_FAILED)
     return NULL;
   handle = dlmem (addr, len, flags, NULL);
   munmap (addr, len);
   return handle;
}

Should I add it to a test-case or fdlopen()
is enough?