kaguya
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
#include <dlfcn.h>
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#include <stdio.h>
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#include <assert.h>
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#ifdef USE_HOST_LIBC
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#define LIBBAR "libnative-bar.so"
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#define LIBBAZ "libnative-baz.so"
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#else
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#define LIBBAR "libbar.so"
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#define LIBBAZ "libbaz.so"
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#endif
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int main() {
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// In this test, we have bar -> foo and baz -> foo (where -> means 'depends on').
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// All three objects contain a definition of a symbol g. Bar calls into foo to retrieve
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// what foo thinks g is, but since bar appears earlier in the scope than foo, bar's copy
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// of g wins.
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//
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// Next, we load baz, which is identical to bar. When baz calls into foo to retrieve g,
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// foo still sees bar's definition of g, so bar's copy of g wins.
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//
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// Swapping the load order of bar and baz should therefore change the value of g which
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// foo sees. This behaviour is why dlmopen exists. If we ever implement that, we should
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// write a similar test and assert that the calls return different results.
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void *libbar = dlopen(LIBBAR, RTLD_LAZY | RTLD_LOCAL);
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int (*call_bar)(void) = dlsym(libbar, "call_bar");
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printf("call_bar: %d\n", call_bar());
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assert(call_bar() == 1);
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void *libbaz = dlopen(LIBBAZ, RTLD_LAZY | RTLD_LOCAL);
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int (*call_baz)(void) = dlsym(libbaz, "call_baz");
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printf("call_baz: %d\n", call_baz());
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assert(call_baz() == 1);
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dlclose(libbar);
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dlclose(libbaz);
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return 0;
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}
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