Add test_vdso_parser

2 files changed, 91 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index bfda8fb..ddf7adc 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,8 @@
 .PHONY: all clean
-all: timing_test_64 timing_test_32 evil-clock-test test_vsyscall_64 test_vsyscall_32 dump-vdso dump-vvar dump-vsyscall context_switch_latency kernel_pf user_visible_state
+all: timing_test_64 timing_test_32 evil-clock-test test_vsyscall_64 test_vsyscall_32 dump-vdso dump-vvar dump-vsyscall context_switch_latency kernel_pf user_visible_state test_vdso_parser_64 test_vdso_parser_32
 
 clean:
-	rm -f timing_test_64 timing_test_32 evil-clock-test test_vsyscall_64 test_vsyscall_32 dump-vdso dump-vvar dump-vsyscall context_switch_latency kernel_pf user_visible_state
+	rm -f timing_test_64 timing_test_32 evil-clock-test test_vsyscall_64 test_vsyscall_32 dump-vdso dump-vvar dump-vsyscall context_switch_latency kernel_pf user_visible_state test_vdso_parser_64 test_vdso_parser_32
 
 user_visible_state: user_visible_state.c
 	gcc -o $@ -O2 -std=gnu99 -Wall $(EXTRA_CFLAGS) -g $^ -lrt -ldl
@@ -25,6 +25,12 @@ test_vsyscall_64: test_vsyscall.cc
 test_vsyscall_32: test_vsyscall.cc
 	g++ -m32 -o $@ -std=gnu++0x -O2 -Wall $(EXTRA_CFLAGS) -g $^ -lrt -ldl
 
+test_vdso_parser_64: test_vdso_parser.cc
+	g++ -m64 -o $@ -std=gnu++0x -O2 -Wall $(EXTRA_CFLAGS) -g $^ -lrt -ldl
+
+test_vdso_parser_32: test_vdso_parser.cc
+	g++ -m32 -o $@ -std=gnu++0x -O2 -Wall $(EXTRA_CFLAGS) -g $^ -lrt -ldl
+
 dump-vdso: dump-vdso.c
 	gcc -o $@ -O2 $(EXTRA_CFLAGS) $^ -ldl
 
diff --git a/test_vdso_parser.cc b/test_vdso_parser.cc
new file mode 100644
index 0000000..f8612c4
--- /dev/null
+++ b/test_vdso_parser.cc
@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <dlfcn.h>
+#include <err.h>
+#include <sys/auxv.h>
+
+#ifndef AT_VDSO_FINDSYM
+# define AT_VDSO_FINDSYM 37
+#endif
+
+struct vdso_entry {
+	const char *name, *version;
+	bool findsym_should_fail;
+};
+
+const struct vdso_entry entries[] = {
+	{ "__vdso_clock_gettime", "LINUX_2.6" },
+	{ "__vdso_clock_gettime", "LINUX_NEW" },
+	{ "__vdso_clock_gettime", "LINUX_MISSPELLED" },
+	{ "__vdso_time", "LINUX_2.6" },
+	{ "__vdso_getcpu", "LINUX_2.6" },
+	{ "__vdso_gettimeofday", "LINUX_2.6" },
+	{ "clock_gettime", "LINUX_2.6", true },
+	{ "time", "LINUX_2.6", true },
+	{ "getcpu", "LINUX_2.6", true },
+	{ "gettimeofday", "LINUX_2.6", true },
+	{ }
+};
+
+/* vsyscalls and vDSO */
+typedef void *(*findsym_t)(const char *name, const char *version);
+
+static void *vdso;
+static findsym_t findsym;
+
+void init_vdso()
+{
+  vdso = dlopen("linux-vdso.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+  if (!vdso)
+	  vdso = dlopen("linux-gate.so.1",
+			RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+  if (!vdso)
+	  errx(1, "Failed to find vDSO\n");
+
+  findsym = (findsym_t)dlvsym(vdso, "__vdso_findsym", "LINUX_2.6");
+  if (!findsym)
+    printf("Warning: failed to find __vdso_findsym in vDSO\n");
+
+  if (findsym != (findsym_t)getauxval(AT_VDSO_FINDSYM))
+    printf("Warning: AT_VDSO_FINDSYM doesn't match __vdso_findsym\n");
+}
+
+void test(const struct vdso_entry *entry)
+{
+	void *findsym_result, *dlvsym_result;
+
+	if (!findsym)
+		return;
+
+	findsym_result = findsym(entry->name, entry->version);
+	dlvsym_result = dlvsym(vdso, entry->name, entry->version);
+
+	if (findsym_result !=
+	    (entry->findsym_should_fail ? NULL : dlvsym_result)) {
+		printf("Finding \"%s\" (ver \"%s\"): findsym says %p but dlvsym says %p\n",
+		       entry->name, entry->version,
+		       findsym_result, dlvsym_result);
+	} else {
+		printf("OK: \"%s\" (ver \"%s\") -> %p (%p)\n",
+		       entry->name, entry->version,
+		       dlvsym_result, findsym_result);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	const struct vdso_entry *e;
+	init_vdso();
+
+	for (e = entries; e->name; e++)
+		test(e);
+
+	return 0;
+}