path: root/src/fenv/fenv.c
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authorRich Felker <>2019-02-26 18:05:19 -0500
committerRich Felker <>2019-02-27 16:05:37 -0500
commit403555690775f7c8806372644f543518e6664e3b (patch)
treeb911790c70b968e61981355dd77d18eb8d794778 /src/fenv/fenv.c
parent71db5dfaa9ddcb65e18ff128c9ed122790d72e2f (diff)
fix and overhaul dlsym depedency order, always record direct deps
dlsym with an explicit handle is specified to use "dependency order", a breadth-first search rooted at the argument. this has always been implemented by iterating a flattened dependency list built at dlopen time. however, the logic for building this list was completely wrong except in trivial cases; it simply used the list of libraries loaded since a given library, and their direct dependencies, as that library's dependencies, which could result in misordering, wrongful omission of deep dependencies from the search, and wrongful inclusion of unrelated libraries in the search. further, libraries did not have any recorded list of resolved dependencies until they were explicitly dlopened, meaning that DT_NEEDED entries had to be resolved again whenever a library participated as a dependency of more than one dlopened library. with this overhaul, the resolved direct dependency list of each library is always recorded when it is first loaded, and can be extended to a full flattened breadth-first search list if dlopen is called on the library. the extension is performed using the direct dependency list as a queue and appending copies of the direct dependency list of each dependency in the queue, excluding duplicates, until the end of the queue is reached. the direct deps remain available for future use as the initial subarray of the full deps array. first-load logic in dlopen is updated to match these changes, and clarified.
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