fix: use static-pie linking for Go examples, remove patch_interp.py

Build with CGO_ENABLED=1 and -extldflags "-static-pie" instead of
patching PT_INTERP out of CGO_ENABLED=0 PIE binaries.

Signed-off-by: danbugs <danilochiarlone@gmail.com>

Author: danbugs

examples/go-http/Dockerfile

@@ -5,22 +5,13 @@ WORKDIR /src
 COPY ./main.go /src/main.go
 
 RUN set -xe; \
-    CGO_ENABLED=0 \
+    CGO_ENABLED=1 \
     GOARCH=amd64 \
     go build \
-      -buildmode=pie \
-      -ldflags="-linkmode=internal" \
+      -ldflags='-linkmode external -extldflags "-static-pie" -s -w' \
       -o /server main.go \
     ;
 
-# Strip PT_INTERP from the static PIE binary: Go's internal linker adds
-# /lib64/ld-linux-x86-64.so.2 as interpreter for PIE on Linux, but the
-# binary is fully self-contained and does not need a dynamic linker.
-# Unikraft's elfloader fails when the interpreter is listed but absent.
-# Patch the program header: change PT_INTERP (type=3) -> PT_NULL (type=0).
-COPY patch_interp.py /patch_interp.py
-RUN python3 /patch_interp.py /server
-
 FROM scratch AS rootfs
 
 COPY --from=build /server /bin/server

examples/go-http/patch_interp.py

@@ -5,22 +5,13 @@ WORKDIR /src
 COPY ./hello.go /src/hello.go
 
 RUN set -xe; \
-    CGO_ENABLED=0 \
+    CGO_ENABLED=1 \
     GOARCH=amd64 \
     go build \
-      -buildmode=pie \
-      -ldflags="-linkmode=internal" \
+      -ldflags='-linkmode external -extldflags "-static-pie" -s -w' \
       -o /hello hello.go \
     ;
 
-# Strip PT_INTERP from the static PIE binary: Go's internal linker adds
-# /lib64/ld-linux-x86-64.so.2 as interpreter for PIE on Linux, but the
-# binary is fully self-contained and does not need a dynamic linker.
-# Unikraft's elfloader fails when the interpreter is listed but absent.
-# Patch the program header: change PT_INTERP (type=3) -> PT_NULL (type=0).
-COPY patch_interp.py /patch_interp.py
-RUN python3 /patch_interp.py /hello
-
 FROM scratch AS rootfs
 
 COPY --from=build /hello /bin/hello