breakpad: disable calls to getcontext() with musl

Musl does not currently provide getcontext().

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-devtools/breakpad/breakpad/0001-disable-calls-to-getcontext-with-musl.patch

@@ -0,0 +1,52 @@
+From 57ecf7205feedd23f901e1bb9d193787e559e433 Mon Sep 17 00:00:00 2001
+From: Andre McCurdy <armccurdy@gmail.com>
+Date: Tue, 23 Jan 2018 15:13:26 -0800
+Subject: [PATCH] disable calls to getcontext() with musl
+
+Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
+---
+ src/client/linux/handler/exception_handler.cc | 17 +++++++++++++++++
+ 1 file changed, 17 insertions(+)
+
+diff --git a/src/client/linux/handler/exception_handler.cc b/src/client/linux/handler/exception_handler.cc
+index cca023f..f3e460c 100644
+--- a/src/client/linux/handler/exception_handler.cc
++++ b/src/client/linux/handler/exception_handler.cc
+@@ -495,7 +495,19 @@ bool ExceptionHandler::SimulateSignalDelivery(int sig) {
+   siginfo.si_code = SI_USER;
+   siginfo.si_pid = getpid();
+   ucontext_t context;
++#if defined(__GLIBC__)
+   getcontext(&context);
++#else
++  // Extreme hack: Allow musl builds to compile - but don't expect them to work.
++  // Although musl provides a definition for getcontext() in ucontext.h (which
++  // enough to build libbreakpad_client) musl does not provide a corresponding
++  // getcontext() function, so builds will fail when attempting to link anything
++  // with libbreakpad_client. Disabling calls to getcontext() is a temporary
++  // hack. The real fix is probably to enable Breakpad's own implementation of
++  // getcontext() when building for musl (it's currently only enabled when
++  // building for Android).
++  memset (&context, 0, sizeof(context));
++#endif
+   return HandleSignal(sig, &siginfo, &context);
+ }
+ 
+@@ -680,9 +692,14 @@ bool ExceptionHandler::WriteMinidump() {
+   sys_prctl(PR_SET_DUMPABLE, 1, 0, 0, 0);
+ 
+   CrashContext context;
++#if defined(__GLIBC__)
+   int getcontext_result = getcontext(&context.context);
+   if (getcontext_result)
+     return false;
++#else
++  // Extreme hack - see comments above.
++  memset (&context.context, 0, sizeof(&context.context));
++#endif
+ 
+ #if defined(__i386__)
+   // In CPUFillFromUContext in minidumpwriter.cc the stack pointer is retrieved
+-- 
+1.9.1
+

meta-oe/recipes-devtools/breakpad/breakpad_git.bb

@@ -41,6 +41,7 @@ SRC_URI = "git://github.com/google/breakpad;name=breakpad \
            file://0005-md2core-Replace-basename.patch \
            file://0002-Use-_fpstate-instead-of-_libc_fpstate-on-linux.patch \
            file://mcontext.patch \
+           file://0001-disable-calls-to-getcontext-with-musl.patch \
            file://0001-lss-Match-syscalls-to-match-musl.patch;patchdir=src/third_party/lss \
            file://mips_asm_sgidefs.patch;patchdir=src/third_party/lss \
 "