From 8e15b08ae22a5230c1fea4779410de0420fa939c Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Wed, 26 Sep 2012 11:44:01 -0700
Subject: [PATCH] Simple tests for dladdr(3).
Change-Id: I22160b7fc9b950ea19adb6da42af2f893f4fe5d5
---
tests/dlopen_test.cpp | 72 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/tests/dlopen_test.cpp b/tests/dlopen_test.cpp
index c290b4d37..c41c5e6ab 100644
--- a/tests/dlopen_test.cpp
+++ b/tests/dlopen_test.cpp
@@ -17,6 +17,12 @@
#include <gtest/gtest.h>
#include <dlfcn.h>
+#include <libgen.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include <string>
static bool gCalled = false;
extern "C" void DlSymTestFunction() {
@@ -36,3 +42,69 @@ TEST(dlopen, dlsym_in_self) {
function();
ASSERT_TRUE(gCalled);
}
+
+TEST(dlopen, dladdr) {
+ void* self = dlopen(NULL, RTLD_NOW);
+ ASSERT_TRUE(self != NULL);
+
+ void* sym = dlsym(self, "DlSymTestFunction");
+ ASSERT_TRUE(sym != NULL);
+
+ // Deliberately ask dladdr for an address inside a symbol, rather than the symbol base address.
+ void* addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(sym) + 2);
+
+ Dl_info info;
+ int rc = dladdr(addr, &info);
+ ASSERT_NE(rc, 0); // Zero on error, non-zero on success.
+
+ // Get the name of this executable.
+ char executable_path[PATH_MAX];
+ rc = readlink("/proc/self/exe", executable_path, sizeof(executable_path));
+ ASSERT_NE(rc, -1);
+ executable_path[rc] = '\0';
+ std::string executable_name(basename(executable_path));
+
+ // The filename should be that of this executable.
+ // Note that we don't know whether or not we have the full path, so we want an "ends_with" test.
+ std::string dli_fname(info.dli_fname);
+ dli_fname = basename(&dli_fname[0]);
+ ASSERT_EQ(dli_fname, executable_name);
+
+ // The symbol name should be the symbol we looked up.
+ ASSERT_STREQ(info.dli_sname, "DlSymTestFunction");
+
+ // The address should be the exact address of the symbol.
+ ASSERT_EQ(info.dli_saddr, sym);
+
+ // Look in /proc/pid/maps to find out what address we were loaded at.
+ // TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic.
+ void* base_address = NULL;
+ char path[PATH_MAX];
+ snprintf(path, sizeof(path), "/proc/%d/maps", getpid());
+ char line[BUFSIZ];
+ FILE* fp = fopen(path, "r");
+ ASSERT_TRUE(fp != NULL);
+ while (fgets(line, sizeof(line), fp) != NULL) {
+ uintptr_t start = strtoul(line, 0, 16);
+ line[strlen(line) - 1] = '\0'; // Chomp the '\n'.
+ char* path = strchr(line, '/');
+ if (strcmp(executable_path, path) == 0) {
+ base_address = reinterpret_cast<void*>(start);
+ break;
+ }
+ }
+ fclose(fp);
+
+ // The base address should be the address we were loaded at.
+ ASSERT_EQ(info.dli_fbase, base_address);
+}
+
+TEST(dlopen, dladdr_invalid) {
+ Dl_info info;
+
+ // No symbol corresponding to NULL.
+ ASSERT_EQ(dladdr(NULL, &info), 0); // Zero on error, non-zero on success.
+
+ // No symbol corresponding to a stack address.
+ ASSERT_EQ(dladdr(&info, &info), 0); // Zero on error, non-zero on success.
+}