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dd32e1db38
This reverts commit6985865bc3. Reason for revert: The commit changes the order of ELF destructor calls too much relative to what applications expect or can handle. In particular, during process exit and _dl_fini, after the revert commit, we no longer call the destructors of the main program first; that only happens after some dlopen'ed objects have been destructed. This robs applications of an opportunity to influence destructor order by calling dlclose explicitly from the main program's ELF destructors. A couple of different approaches involving reverse constructor order were tried, and none of them worked really well. It seems we need to keep the dependency sorting in _dl_fini. There is also an ambiguity regarding nested dlopen calls from ELF constructors: Should those destructors run before or after the object that called dlopen? Commit6985865bc3used reverse order of the start of ELF constructor calls for destructors, but arguably using completion of constructors is more correct. However, that alone is not sufficient to address application compatibility issues (it does not change _dl_fini ordering at all).
74 lines
3.4 KiB
Modula-2
74 lines
3.4 KiB
Modula-2
# DSO sorting test descriptions.
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# This file is to be processed by ../scripts/dso-ordering-test.py, see usage
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# in elf/Makefile for how it is executed.
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# We test both dynamic loader sorting algorithms
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tunable_option: glibc.rtld.dynamic_sort=1
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tunable_option: glibc.rtld.dynamic_sort=2
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# Sequence of single dependencies with no cycles.
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tst-dso-ordering1: a->b->c
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output: c>b>a>{}<a<b<c
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# Sequence including 2 dependent DSOs not at the end of the graph.
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tst-dso-ordering2: a->b->[cd]->e
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output: e>d>c>b>a>{}<a<b<c<d<e
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# Complex order with 3 "layers" of full dependencies
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tst-dso-ordering3: a->[bc]->[def]->[gh]->i
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output: i>h>g>f>e>d>c>b>a>{}<a<b<c<d<e<f<g<h<i
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# Sequence including 2 dependent DSOs at the end of the graph.
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# Additionally the same dependencies appear in two paths.
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tst-dso-ordering4: a->b->[de];a->c->d->e
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output: e>d>c>b>a>{}<a<b<c<d<e
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# Test that b->c cross link is respected correctly
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tst-dso-ordering5: a!->[bc]->d;b->c
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output: d>c>b>a>{}<a<b<c<d
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# First DSO fully dependent on 4 DSOs, with another DSO at the end of chain.
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tst-dso-ordering6: a->[bcde]->f
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output: f>e>d>c>b>a>{}<a<b<c<d<e<f
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# Sequence including 2 dependent and 3 dependent DSOs, and one of the
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# dependent DSOs is dependent on an earlier DSO.
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tst-dso-ordering7: a->[bc];b->[cde];e->f
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output: f>e>d>c>b>a>{}<a<b<c<d<e<f
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# Sequence where the DSO c is unerlinked and calls a function in DSO a which
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# is technically a cycle. The main executable depends on the first two DSOs.
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# Note: This test has unspecified behavior.
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tst-dso-ordering8: a->b->c=>a;{}->[ba]
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output: c>b>a>{}<a<b<c
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# Generate the permutation of DT_NEEDED order between the main binary and
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# all 5 DSOs; all link orders should produce exact same init/fini ordering
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tst-dso-ordering9: a->b->c->d->e;{}!->[abcde]
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output: e>d>c>b>a>{}<a<b<c<d<e
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# Test if init/fini ordering behavior is proper, despite main program with
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# an soname that may cause confusion
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tst-dso-ordering10: {}->a->b->c;soname({})=c
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output: b>a>{}<a<b
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# Complex example from Bugzilla #15311, under-linked and with circular
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# relocation(dynamic) dependencies. While this is technically unspecified, the
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# presumed reasonable practical behavior is for the destructor order to respect
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# the static DT_NEEDED links (here this means the a->b->c->d order).
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# The older dynamic_sort=1 algorithm does not achieve this, while the DFS-based
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# dynamic_sort=2 algorithm does, although it is still arguable whether going
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# beyond spec to do this is the right thing to do.
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# The below expected outputs are what the two algorithms currently produce
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# respectively, for regression testing purposes.
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tst-bz15311: {+a;+e;+f;+g;+d;%d;-d;-g;-f;-e;-a};a->b->c->d;d=>[ba];c=>a;b=>e=>a;c=>f=>b;d=>g=>c
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output(glibc.rtld.dynamic_sort=1): {+a[d>c>b>a>];+e[e>];+f[f>];+g[g>];+d[];%d(b(e(a()))a()g(c(a()f(b(e(a()))))));-d[];-g[];-f[];-e[];-a[<a<c<d<g<f<b<e];}
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output(glibc.rtld.dynamic_sort=2): {+a[d>c>b>a>];+e[e>];+f[f>];+g[g>];+d[];%d(b(e(a()))a()g(c(a()f(b(e(a()))))));-d[];-g[];-f[];-e[];-a[<g<f<a<b<c<d<e];}
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# Test that even in the presence of dependency loops involving dlopen'ed
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# object, that object is initialized last (and not unloaded prematurely).
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# Final destructor order is indeterminate due to the cycle.
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tst-bz28937: {+a;+b;-b;+c;%c};a->a1;a->a2;a2->a;b->b1;c->a1;c=>a1
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output(glibc.rtld.dynamic_sort=1): {+a[a2>a1>a>];+b[b1>b>];-b[<b<b1];+c[c>];%c(a1());}<a<a2<c<a1
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output(glibc.rtld.dynamic_sort=2): {+a[a2>a1>a>];+b[b1>b>];-b[<b<b1];+c[c>];%c(a1());}<a2<a<c<a1
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