On Thu, 2002-08-22 at 00:11, Henrique de Moraes Holschuh wrote: > On Wed, 21 Aug 2002, Luca Barbieri wrote: > > This is an another problem that would be easily and compatibly solved by > > my ELF extension (until the library gets properly fixed upstream). > > Yes and no. Versioned symbols are here NOW and can be used NOW, and they fix > the issue cleanly without drawbacks: they are as painful as a > do-it-only-once global soname increase (which is quite painful though). I just got a Great Idea(tm).
This is the explanation from Ulrich Drepper: In case only the object file with the reference does not use versioning but the object with the definition does, then the reference only matches the base definition. The base definition is the one with index numbers 1 and 2 (1 is the unspecified name, 2 is the name given later to the baseline of symbols once the library started using symbol versioning). The static linker is guaranteed to use this indeces for the base definition. If there is no symbol definition with such an version index and there is exactly one version for which this symbol is defined, then this version is accepted (this was mostly implemented for dlopen() calls as it will normally not happen when the static linker is used). However this the problem: Otherwise, if more then one version of the symbol is available, none of the definitions is accepted and the search continues with the next object. If we modify the loader so that it instead accepts the first one, this first one will be correct for the main program. So if we modify the loader to do this and recompile the conflicting libraries and the ones that use them we can address both the short-term and the long-term issues while still allowing symbols to overridden. With unmodified loaders and multiple versioned libraries in a program, the binaries will fail until they are recompiled to use versioned symbols. However this isn't worse than the current situation that causes them to pseudorandomly fail. Furthermore, since the binary would fail I don't think that anything relies on the existing behavior. Also, there is no chance of creating incompatible ELF formats since the format isn't changed. How about this? This seems better than using my patch. Am I missing something?
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