Fix handling of ro segments for embedded libs.
When a shared library is loaded directly from an apk, the new way the
linker splits a shared library into a read-only and execute segment
broke unwinding. Modify the code to handle this case.
Other changes:
- Modify the algorithm for finding read-only map entries. Before, the code
would search the entire map for the closest offset. Now it simply looks
at the previous map. I did this because the old code was too lenient and
might still work even if the linker changes. I want this to break if the
linker behavior changes so that I can analyze the change.
- Update the tools to use PTRACE_SEIZE instead of PTRACE_ATTACH since
PTRACE_ATTACH doesn't work in all cases.
- Small refactor of the GetFileMemory function.
- Add new unit test cases and new offline unwind test cases.
Bug: 120618231
Test: Ran new unit tests, ran original failing test.
Change-Id: I4bade55cf33220d52f1d5e9b0cbbbcc8419669d4
diff --git a/libunwindstack/tools/unwind.cpp b/libunwindstack/tools/unwind.cpp
index 22ca7bf..e729453 100644
--- a/libunwindstack/tools/unwind.cpp
+++ b/libunwindstack/tools/unwind.cpp
@@ -35,7 +35,12 @@
#include <unwindstack/Unwinder.h>
static bool Attach(pid_t pid) {
- if (ptrace(PTRACE_ATTACH, pid, 0, 0) == -1) {
+ if (ptrace(PTRACE_SEIZE, pid, 0, 0) == -1) {
+ return false;
+ }
+
+ if (ptrace(PTRACE_INTERRUPT, pid, 0, 0) == -1) {
+ ptrace(PTRACE_DETACH, pid, 0, 0);
return false;
}