Merge pull request #1 from resin-io/reapply-2.5.x-patches

Reapply 2.5.x patches

.dockerignore

@@ -0,0 +1 @@
+Dockerfile

Dockerfile

@@ -0,0 +1,27 @@
+# Use this dockerfile to build the qemu binary
+
+FROM debian:jessie
+
+RUN apt-get update \
+	&& apt-get install -y \
+		autoconf \
+		bison \
+		build-essential \
+		flex \
+		libglib2.0-dev \
+		libtool \
+		make \
+		pkg-config \
+		python \
+		zlib1g-dev \
+	&& rm -rf /var/lib/apt/lists/*
+
+WORKDIR /usr/src/qemu
+
+COPY . /usr/src/qemu
+
+
+ARG TARGET_ARCH=arm-linux-user
+RUN ./configure --target-list=$TARGET_ARCH --static
+
+RUN make -j $(nproc)

linux-user/signal.c

@@ -744,6 +744,27 @@ int do_sigaction(int sig, const struct target_sigaction *act,
     }
 
     k = &sigact_table[sig - 1];
+
+    /* This signal will always fail. This causes golang crash since
+     * https://github.com/golang/go/commit/675eb72c285cd0dd44a5f280bb3fa456ddf6de16
+     *
+     * As explained in that commit, these signals are very rarely used in a
+     * way that causes problems, so it's ok-ish to ignore one of them here.
+     */
+    if (sig == 33) {
+        return 0;
+    }
+    /* This signal will fail because QEMU uses SIGRTMAX for itself. This causes
+     * golang to crash for versions earlier than
+     * https://github.com/golang/go/commit/d10675089d74db0408f2432eae3bd89a8e1c2d6a
+     *
+     * Since after that commit golang ignores that signal, we also ignore it here to
+     * allow earlier versions to run as well.
+     */
+    if (sig == 64) {
+        return 0;
+    }
+
     if (oact) {
         __put_user(k->_sa_handler, &oact->_sa_handler);
         __put_user(k->sa_flags, &oact->sa_flags);