[Bug dynamic-link/28008] New: [Feature request] dlopen_from function

[Bug dynamic-link/28008] New: [Feature request] dlopen_from function

[jakobrs100+sourceware at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28008

            Bug ID: 28008
           Summary: [Feature request] dlopen_from function
           Product: glibc
           Version: unspecified
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: dynamic-link
          Assignee: unassigned at sourceware dot org
          Reporter: jakobrs100+sourceware at gmail dot com
  Target Milestone: ---

The behaviour of certain functions in libdl[^2] like the `dlopen`
function is dependent on where it is called from. This is normally
what you want, but sometimes you may want to specify the caller
address yourself, for example when intercepting/hooking the `dlopen`
function itself. For this reason, Apple has added the `dlopen_from`
function in macOS Big Sur. `dlopen_from` has an extra parameter, `void
*caller`, that specifies the "fake" caller address to be used instead
of `RETURN_ADDRESS(0)`[^3]. Using `dlopen_from` significantly
simplifies intercepting `dlopen` calls (see [here][1] for an example).
So my feature request is to implement `dlopen_from` in glibc too.

[1]:
<https://github.com/clementgallet/libTAS/blob/70966f9e1f400dfdd5176bba63c11cb6026d3da6/src/library/dlhook.cpp#L108-L189>
[^2]: The same logic also applies to `dlmopen`, `dlsym`, and `dlvsym`.
[^3]: Header file where `dlopen_from` is declared:
<https://opensource.apple.com/source/dyld/dyld-832.7.3/include/dlfcn_private.h.auto.html>

(From libc-help here:
<https://sourceware.org/pipermail/libc-help/2021-June/005910.html>)

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[Bug dynamic-link/28008] [Feature request] dlopen_from function

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28008

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |valery_reznic at yahoo dot com

--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
*** Bug 28927 has been marked as a duplicate of this bug. ***

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[Bug dynamic-link/28008] [Feature request] dlopen_from function

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28008

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
              Flags|                            |security-
         Resolution|---                         |DUPLICATE
                 CC|                            |fweimer at redhat dot com

--- Comment #2 from Florian Weimer <fweimer at redhat dot com> ---
It turns out we have an even earlier RFE for this.

In the meantime, you might consider using LD_AUDIT.

*** This bug has been marked as a duplicate of bug 25114 ***

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