Demand read load bias for a map.
Add a static GetLoadBias method to the Elf object that only reads just
enough to get the load bias.
Add a method to MapInfo that gets the load bias. First attempt to get
it if the elf object already exists. If no elf object was created, use
the new static method to get the load bias.
In BacktraceMap, add a custom iterator so that when code dereferences
a map element, that's when the load bias will be retrieved if it hasn't
already been set.
Bug: 69871050
Test: New unit tests, verify tombstones have non-zero load bias values for
Test: libraries with a non-zero load bias.
Change-Id: I125f4abc827589957fce2f0df24b0f25d037d732
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index 9911e74..890ab3f 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -857,6 +857,34 @@
static bool map_sort(map_test_t i, map_test_t j) { return i.start < j.start; }
+static std::string GetTestMapsAsString(const std::vector<map_test_t>& maps) {
+ if (maps.size() == 0) {
+ return "No test map entries\n";
+ }
+ std::string map_txt;
+ for (auto map : maps) {
+ map_txt += android::base::StringPrintf("%" PRIxPTR "-%" PRIxPTR "\n", map.start, map.end);
+ }
+ return map_txt;
+}
+
+static std::string GetMapsAsString(BacktraceMap* maps) {
+ if (maps->size() == 0) {
+ return "No map entries\n";
+ }
+ std::string map_txt;
+ for (const backtrace_map_t* map : *maps) {
+ map_txt += android::base::StringPrintf(
+ "%" PRIxPTR "-%" PRIxPTR " flags: 0x%x offset: 0x%" PRIxPTR " load_bias: 0x%" PRIxPTR,
+ map->start, map->end, map->flags, map->offset, map->load_bias);
+ if (!map->name.empty()) {
+ map_txt += ' ' + map->name;
+ }
+ map_txt += '\n';
+ }
+ return map_txt;
+}
+
static void VerifyMap(pid_t pid) {
char buffer[4096];
snprintf(buffer, sizeof(buffer), "/proc/%d/maps", pid);
@@ -875,12 +903,20 @@
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(pid));
// Basic test that verifies that the map is in the expected order.
- ScopedBacktraceMapIteratorLock lock(map.get());
- std::vector<map_test_t>::const_iterator test_it = test_maps.begin();
- for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
- ASSERT_TRUE(test_it != test_maps.end());
- ASSERT_EQ(test_it->start, it->start);
- ASSERT_EQ(test_it->end, it->end);
+ auto test_it = test_maps.begin();
+ for (auto it = map->begin(); it != map->end(); ++it) {
+ ASSERT_TRUE(test_it != test_maps.end()) << "Mismatch in number of maps, expected test maps:\n"
+ << GetTestMapsAsString(test_maps) << "Actual maps:\n"
+ << GetMapsAsString(map.get());
+ ASSERT_EQ(test_it->start, (*it)->start) << "Mismatch in map data, expected test maps:\n"
+ << GetTestMapsAsString(test_maps) << "Actual maps:\n"
+ << GetMapsAsString(map.get());
+ ASSERT_EQ(test_it->end, (*it)->end) << "Mismatch maps in map data, expected test maps:\n"
+ << GetTestMapsAsString(test_maps) << "Actual maps:\n"
+ << GetMapsAsString(map.get());
+ // Make sure the load bias get set to a value.
+ ASSERT_NE(static_cast<uint64_t>(-1), (*it)->load_bias) << "Found uninitialized load_bias\n"
+ << GetMapsAsString(map.get());
++test_it;
}
ASSERT_TRUE(test_it == test_maps.end());