Bring libc implementation of tuxreaperd up to speed with asm version, Backported the race-free wait loop from tuxreaperdasm.c

DEVLOG.md

@@ -1,6 +1,6 @@
 # Tux-Dock Development Log
 
-## 0.2-beta
+## 0.3-beta
 
 This release introduces `tuxreaperd`, a micro init system for containers.
 

README.md

@@ -52,9 +52,12 @@ sudo ./build/tux-dock
 
 # Override the report server port
 ./compile.sh --web-test-view 9000
+
+# Force the libc-based tuxreaperd implementation
+./compile.sh --force-libc-reaper
 ```
 
-`compile.sh` builds the `tuxreaperd` micro init before the main project. On supported hosts (`x86_64`/`amd64`/`aarch64`/`arm64`) it first tries the freestanding syscall implementation in `tuxreaperdasm.c`; on other architectures, or if the freestanding build fails, it falls back to the standard POSIX implementation in `tuxreaperdgnu.c`.
+`compile.sh` builds the `tuxreaperd` micro init before the main project. On supported hosts (`x86_64`/`amd64`/`aarch64`/`arm64`) it first tries the freestanding syscall implementation in `tuxreaperdasm.c`; on other architectures, or if the freestanding build fails, it falls back to the standard POSIX implementation in `tuxreaperdgnu.c`. Pass `--force-libc-reaper` to skip the freestanding build and use the libc implementation directly.
 
 The web report is generated under `/tmp` and includes exact CTest output, test summaries, Docker integration output, a text rendition of the TUI flow, and the tuxreaperd zombie-reaping results. It requires `nc`, `netcat`, or Nmap's `ncat`; press `Ctrl-C` to stop the server. The default port is `8095`; pass a port after `--web-test-view` to override it. `--web-test-view --no-test` is invalid. Normal test runs include a Docker integration test using `debian:forky`, so Docker must be available. On systems with 1 GB or less of available memory, the script automatically uses a smaller build configuration and a single build job.
 
@@ -122,7 +125,7 @@ ctest --test-dir build --output-on-failure
 
 ## About / Version
 
-- Version: `0.2-beta`
+- Version: `0.3-beta`
 - Created by: `markmental`
 - GitHub: https://github.com/MARKMENTAL/tuxdock
 - Forgejo: https://mentalnet.xyz/forgejo-v2/markmental/tuxdock

compile.sh

@@ -5,6 +5,7 @@ set -eu
 run_tests=1
 web_view=0
 web_port=8095
+force_libc_reaper=0
 
 memory_limit=$(cat /sys/fs/cgroup/memory.max 2>/dev/null || true)
 if [ -z "$memory_limit" ] || [ "$memory_limit" = max ]; then
@@ -44,8 +45,9 @@ while [ "$#" -gt 0 ]; do
                 shift
             fi
             ;;
+        --force-libc-reaper) force_libc_reaper=1 ;;
         *)
-            printf '%s\n' "Usage: $0 [--no-test] [--web-test-view [port]]" >&2
+            printf '%s\n' "Usage: $0 [--no-test] [--web-test-view [port]] [--force-libc-reaper]" >&2
             exit 2
             ;;
     esac
@@ -81,18 +83,24 @@ command -v gcc >/dev/null 2>&1 || {
 
 host_arch=$(uname -m)
 asm_archs='x86_64 amd64 aarch64 arm64'
+page_size=$(getconf PAGE_SIZE 2>/dev/null || printf '%s\n' 4096)
 build_tuxreaperd() {
     case " $asm_archs " in
         *" $host_arch "*)
-            printf '%s\n' "[compile] Building freestanding tuxreaperd for $host_arch"
-            if gcc -nostdlib -static -fno-stack-protector -fno-asynchronous-unwind-tables \
-                   -fno-builtin -O2 -s -Wl,--build-id=none -Wl,-z,noseparate-code \
-                   -Wall -Wextra tuxreaperdasm.c -o build/tuxreaperd 2>/tmp/tuxreaperd-asm-build.log; then
-                printf '%s\n' "[compile] Freestanding tuxreaperd built successfully"
-                return 0
+            if [ "$force_libc_reaper" -eq 0 ]; then
+                printf '%s\n' "[compile] Building freestanding tuxreaperd for $host_arch"
+                if gcc -nostdlib -static -fno-stack-protector -fno-asynchronous-unwind-tables \
+                       -fno-builtin -O2 -s -Wl,--build-id=none -Wl,-z,noseparate-code \
+                       -Wl,-z,max-page-size=${page_size} \
+                       -Wall -Wextra tuxreaperdasm.c -o build/tuxreaperd 2>/tmp/tuxreaperd-asm-build.log; then
+                    printf '%s\n' "[compile] Freestanding tuxreaperd built successfully"
+                    return 0
+                fi
+                printf '%s\n' "[compile] Freestanding build failed, falling back to libc implementation" >&2
+                cat /tmp/tuxreaperd-asm-build.log >&2
+            else
+                printf '%s\n' "[compile] --force-libc-reaper set, building libc tuxreaperd"
             fi
-            printf '%s\n' "[compile] Freestanding build failed, falling back to libc implementation" >&2
-            cat /tmp/tuxreaperd-asm-build.log >&2
             ;;
     esac
 

tuxreaperdgnu.c

@@ -59,6 +59,15 @@ int main(int argc, char *argv[]) {
     sa_chld.sa_flags = SA_RESTART | SA_NOCLDSTOP;
     sigaction(SIGCHLD, &sa_chld, NULL);
 
+    // Block the signals we wait on so the check/suspend loop is race-free
+    sigset_t block_mask, old_mask;
+    sigemptyset(&block_mask);
+    sigaddset(&block_mask, SIGCHLD);
+    sigaddset(&block_mask, SIGTERM);
+    sigaddset(&block_mask, SIGINT);
+    sigaddset(&block_mask, SIGHUP);
+    sigprocmask(SIG_BLOCK, &block_mask, &old_mask);
+
     // Spawn the primary workload
     g_main_child = fork();
     if (g_main_child < 0) {
@@ -67,6 +76,7 @@ int main(int argc, char *argv[]) {
     }
 
     if (g_main_child == 0) {
+        sigprocmask(SIG_SETMASK, &old_mask, NULL);
         execvp(argv[1], &argv[1]);
         perror("execvp");
         _exit(127);
@@ -74,7 +84,7 @@ int main(int argc, char *argv[]) {
 
     // Block until the primary process exits
     while (!g_child_exited) {
-        pause();
+        sigsuspend(&old_mask);
     }
 
     // Final sweep of any remaining lingering zombies