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

This reverts commit bd1e178.

Author: danbugs

examples/go-http/Dockerfile

@@ -5,13 +5,22 @@ WORKDIR /src
 COPY ./main.go /src/main.go
 
 RUN set -xe; \
-    CGO_ENABLED=1 \
+    CGO_ENABLED=0 \
     GOARCH=amd64 \
     go build \
-      -ldflags='-linkmode external -extldflags "-static-pie" -s -w' \
+      -buildmode=pie \
+      -ldflags="-linkmode=internal" \
       -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

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Strip PT_INTERP from a static PIE binary.
+
+Go's internal linker adds /lib64/ld-linux-x86-64.so.2 as PT_INTERP for PIE
+binaries on Linux, but a CGO_ENABLED=0 binary is fully self-contained and
+does not need a dynamic linker. Patch PT_INTERP -> PT_NULL so elfloaders
+that reject missing interpreters will load the binary directly.
+"""
+import struct
+import sys
+
+path = sys.argv[1]
+with open(path, "rb") as f:
+    data = bytearray(f.read())
+
+e_phoff,     = struct.unpack_from("<Q", data, 32)
+e_phentsize, = struct.unpack_from("<H", data, 54)
+e_phnum,     = struct.unpack_from("<H", data, 56)
+
+for i in range(e_phnum):
+    off = e_phoff + i * e_phentsize
+    p_type, = struct.unpack_from("<I", data, off)
+    if p_type == 3:  # PT_INTERP
+        struct.pack_into("<I", data, off, 0)  # PT_NULL
+        print(f"Patched PT_INTERP -> PT_NULL at program header index {i}")
+
+with open(path, "wb") as f:
+    f.write(data)

examples/go/Dockerfile

@@ -5,13 +5,22 @@ WORKDIR /src
 COPY ./hello.go /src/hello.go
 
 RUN set -xe; \
-    CGO_ENABLED=1 \
+    CGO_ENABLED=0 \
     GOARCH=amd64 \
     go build \
-      -ldflags='-linkmode external -extldflags "-static-pie" -s -w' \
+      -buildmode=pie \
+      -ldflags="-linkmode=internal" \
       -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

examples/go/patch_interp.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Strip PT_INTERP from a static PIE binary.
+
+Go's internal linker adds /lib64/ld-linux-x86-64.so.2 as PT_INTERP for PIE
+binaries on Linux, but a CGO_ENABLED=0 binary is fully self-contained and
+does not need a dynamic linker. Patch PT_INTERP -> PT_NULL so elfloaders
+that reject missing interpreters will load the binary directly.
+"""
+import struct
+import sys
+
+path = sys.argv[1]
+with open(path, "rb") as f:
+    data = bytearray(f.read())
+
+e_phoff,     = struct.unpack_from("<Q", data, 32)
+e_phentsize, = struct.unpack_from("<H", data, 54)
+e_phnum,     = struct.unpack_from("<H", data, 56)
+
+for i in range(e_phnum):
+    off = e_phoff + i * e_phentsize
+    p_type, = struct.unpack_from("<I", data, off)
+    if p_type == 3:  # PT_INTERP
+        struct.pack_into("<I", data, off, 0)  # PT_NULL
+        print(f"Patched PT_INTERP -> PT_NULL at program header index {i}")
+
+with open(path, "wb") as f:
+    f.write(data)