From 22ad627c93f00caf56631a681e79c4f853cf9589 Mon Sep 17 00:00:00 2001
From: gregclermont <580609+gregclermont@users.noreply.github.com>
Date: Fri, 23 Jan 2026 20:29:16 +0100
Subject: [PATCH] Fix docker-compile -o flag passed to docker instead of
 container

The -o/--output flag was being placed before the image name in the
docker run command, causing docker to interpret it as a docker flag
rather than an argument for the container's entrypoint.

Changes:
- CLI: Place -o flag after image and sources
- entrypoint.sh: Replace getopts with manual parsing to accept -o
  in any position (before or after sources)
- Docs: Update examples to use more intuitive `src/*.bpf.c -o build/`
  ordering

Fixes #60

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 DEVELOPMENT.md       |  2 +-
 GUIDE.md             |  2 +-
 docker/entrypoint.sh | 26 ++++++++++++++++++--------
 llms.txt             |  2 +-
 src/tinybpf/_cli.py  |  5 ++---
 5 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index f8db14f..d368d6a 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -150,7 +150,7 @@ tinybpf provides a Docker image for compiling eBPF programs. It bundles libbpf h
 make compile
 
 # Advanced: run docker directly (on Linux, or inside Lima shell on macOS)
-docker run --rm -v $(pwd):/src ghcr.io/gregclermont/tinybpf-compile -o build/ src/*.bpf.c
+docker run --rm -v $(pwd):/src ghcr.io/gregclermont/tinybpf-compile src/*.bpf.c -o build/
 docker run --rm -v $(pwd):/src -e EXTRA_CFLAGS="-DDEBUG" ghcr.io/gregclermont/tinybpf-compile program.bpf.c
 ```
 
diff --git a/GUIDE.md b/GUIDE.md
index 5cc1887..a667155 100644
--- a/GUIDE.md
+++ b/GUIDE.md
@@ -14,7 +14,7 @@ tinybpf docker-compile program.bpf.c
 tinybpf docker-compile src/*.bpf.c
 
 # Output to specific directory
-tinybpf docker-compile -o build/ src/*.bpf.c
+tinybpf docker-compile src/*.bpf.c -o build/
 ```
 
 The CLI uses a Docker image with libbpf headers and `vmlinux.h` (kernel 6.18) for CO-RE support. Output `.bpf.o` files are written alongside sources (or to the specified output directory).
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index d012a72..2df7884 100644
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -56,7 +56,7 @@ if [ $# -eq 0 ]; then
     echo ""
     echo "Examples:"
     echo "  docker run --rm -v \$(pwd):/src ghcr.io/gregclermont/tinybpf-compile program.bpf.c"
-    echo "  docker run --rm -v \$(pwd):/src ghcr.io/gregclermont/tinybpf-compile -o build/ src/*.bpf.c"
+    echo "  docker run --rm -v \$(pwd):/src ghcr.io/gregclermont/tinybpf-compile src/*.bpf.c -o build/"
     echo ""
     echo "  # Use custom vmlinux.h for older kernel:"
     echo "  docker run --rm -v \$(pwd):/src -v /path/to/vmlinux.h:/vmlinux.h -e VMLINUX=/vmlinux.h \\"
@@ -64,15 +64,25 @@ if [ $# -eq 0 ]; then
     exit 0
 fi
 
-# Parse options
+# Parse arguments (options can appear anywhere)
 OUTPUT_DIR=""
-while getopts "o:" opt; do
-    case $opt in
-        o) OUTPUT_DIR="$OPTARG" ;;
-        *) exit 1 ;;
+SOURCES=()
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -o)
+            if [ -z "$2" ]; then
+                echo "Error: -o requires an argument" >&2
+                exit 1
+            fi
+            OUTPUT_DIR="$2"
+            shift 2
+            ;;
+        *)
+            SOURCES+=("$1")
+            shift
+            ;;
     esac
 done
-shift $((OPTIND - 1))
 
 # Create output directory if specified
 if [ -n "$OUTPUT_DIR" ]; then
@@ -81,7 +91,7 @@ fi
 
 # Compile each source file
 FAILED=0
-for src in "$@"; do
+for src in "${SOURCES[@]}"; do
     if [ ! -f "$src" ]; then
         echo "Error: File not found: $src" >&2
         FAILED=1
diff --git a/llms.txt b/llms.txt
index f281bd4..a3876c2 100644
--- a/llms.txt
+++ b/llms.txt
@@ -145,7 +145,7 @@ BtfKind.INT, STRUCT, UNION, ARRAY, PTR, TYPEDEF, FLOAT, ...  # BTF type kinds
 
 ```bash
 tinybpf docker-compile program.bpf.c
-tinybpf docker-compile -o build/ src/*.bpf.c
+tinybpf docker-compile src/*.bpf.c -o build/
 ```
 
 Uses a Docker image with libbpf headers and vmlinux.h (kernel 6.18, x86_64/aarch64) for CO-RE support. Output `.bpf.o` files are written alongside sources or to specified output directory.
diff --git a/src/tinybpf/_cli.py b/src/tinybpf/_cli.py
index be1e02c..a3c93c8 100644
--- a/src/tinybpf/_cli.py
+++ b/src/tinybpf/_cli.py
@@ -52,15 +52,14 @@ def cmd_docker_compile(args: argparse.Namespace) -> int:
         "--rm",
         "-v",
         f"{cwd}:/src",
+        image_tag,
+        *args.sources,
     ]
 
     # Pass through output directory if specified
     if args.output:
         docker_cmd.extend(["-o", args.output])
 
-    docker_cmd.append(image_tag)
-    docker_cmd.extend(args.sources)
-
     if args.verbose:
         print(f"Running: {' '.join(docker_cmd)}", file=sys.stderr)