1 files changed, 34 insertions, 8 deletions

diff --git a/libcorkscrew/arch-x86/backtrace-x86.c b/libcorkscrew/arch-x86/backtrace-x86.c
index 6cdb0c8..fb79a0c 100644
--- a/libcorkscrew/arch-x86/backtrace-x86.c
+++ b/libcorkscrew/arch-x86/backtrace-x86.c
@@ -35,18 +35,50 @@
 
 #if defined(__BIONIC__)
 
+#if defined(__BIONIC_HAVE_UCONTEXT_T)
+
 // Bionic offers the Linux kernel headers.
 #include <asm/sigcontext.h>
 #include <asm/ucontext.h>
 typedef struct ucontext ucontext_t;
 
-#else
+#else /* __BIONIC_HAVE_UCONTEXT_T */
+
+/* Old versions of the Android <signal.h> didn't define ucontext_t. */
+
+typedef struct {
+  uint32_t  gregs[32];
+  void*     fpregs;
+  uint32_t  oldmask;
+  uint32_t  cr2;
+} mcontext_t;
+
+enum {
+  REG_GS = 0, REG_FS, REG_ES, REG_DS,
+  REG_EDI, REG_ESI, REG_EBP, REG_ESP,
+  REG_EBX, REG_EDX, REG_ECX, REG_EAX,
+  REG_TRAPNO, REG_ERR, REG_EIP, REG_CS,
+  REG_EFL, REG_UESP, REG_SS
+};
+
+/* Machine context at the time a signal was raised. */
+typedef struct ucontext {
+    uint32_t uc_flags;
+    struct ucontext* uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    uint32_t uc_sigmask;
+} ucontext_t;
+
+#endif /* __BIONIC_HAVE_UCONTEXT_T */
+
+#else /* __BIONIC__ */
 
 // glibc has its own renaming of the Linux kernel's structures.
 #define __USE_GNU // For REG_EBP, REG_ESP, and REG_EIP.
 #include <ucontext.h>
 
-#endif
+#endif /* __ BIONIC__ */
 
 /* Unwind state. */
 typedef struct {
@@ -96,15 +128,9 @@ ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo __attribute__((unused)),
     const ucontext_t* uc = (const ucontext_t*)sigcontext;
 
     unwind_state_t state;
-#if defined(__BIONIC__)
-    state.ebp = uc->uc_mcontext.ebp;
-    state.esp = uc->uc_mcontext.esp;
-    state.eip = uc->uc_mcontext.eip;
-#else
     state.ebp = uc->uc_mcontext.gregs[REG_EBP];
     state.esp = uc->uc_mcontext.gregs[REG_ESP];
     state.eip = uc->uc_mcontext.gregs[REG_EIP];
-#endif
 
     memory_t memory;
     init_memory(&memory, map_info_list);