From eeb9f98e5bd9d4fac6706edb87d06bf757f0fb79 Mon Sep 17 00:00:00 2001 From: Ophestra Date: Thu, 30 Oct 2025 00:46:23 +0900 Subject: [PATCH] internal/outcome/shim: move signal constants The magic numbers hurt readability. Signed-off-by: Ophestra --- internal/outcome/shim-signal.c | 19 ++++++++----------- internal/outcome/shim-signal.h | 8 ++++++++ internal/outcome/shim.go | 19 +++++++++++++++---- internal/outcome/shim_test.go | 4 ++-- 4 files changed, 33 insertions(+), 17 deletions(-) diff --git a/internal/outcome/shim-signal.c b/internal/outcome/shim-signal.c index fc00534..7e56206 100644 --- a/internal/outcome/shim-signal.c +++ b/internal/outcome/shim-signal.c @@ -8,35 +8,32 @@ static pid_t hakurei_shim_param_ppid = -1; static int hakurei_shim_fd = -1; -static ssize_t hakurei_shim_write(const void *buf, size_t count) { +/* see shim.go for handling of the message */ +static inline ssize_t hakurei_shim_write(hakurei_shim_msg msg) { int savedErrno = errno; - ssize_t ret = write(hakurei_shim_fd, buf, count); + unsigned char buf = (unsigned char)msg; + ssize_t ret = write(hakurei_shim_fd, &buf, 1); if (ret == -1 && errno != EAGAIN) exit(EXIT_FAILURE); errno = savedErrno; return ret; } -/* see shim_linux.go for handling of the value */ static void hakurei_shim_sigaction(int sig, siginfo_t *si, void *ucontext) { if (sig != SIGCONT || si == NULL) { - /* unreachable */ - hakurei_shim_write("\2", 1); + hakurei_shim_write(HAKUREI_SHIM_INVALID); return; } if (si->si_pid == hakurei_shim_param_ppid) { - /* monitor requests shim exit */ - hakurei_shim_write("\0", 1); + hakurei_shim_write(HAKUREI_SHIM_EXIT_REQUESTED); return; } - /* unexpected si_pid */ - hakurei_shim_write("\3", 1); + hakurei_shim_write(HAKUREI_SHIM_BAD_PID); if (getppid() != hakurei_shim_param_ppid) - /* shim orphaned before monitor delivers a signal */ - hakurei_shim_write("\1", 1); + hakurei_shim_write(HAKUREI_SHIM_ORPHAN); } void hakurei_shim_setup_cont_signal(pid_t ppid, int fd) { diff --git a/internal/outcome/shim-signal.h b/internal/outcome/shim-signal.h index bdeae3b..b0229a9 100644 --- a/internal/outcome/shim-signal.h +++ b/internal/outcome/shim-signal.h @@ -1,3 +1,11 @@ #include +/* see shim.go for documentation */ +typedef enum { + HAKUREI_SHIM_EXIT_REQUESTED, + HAKUREI_SHIM_ORPHAN, + HAKUREI_SHIM_INVALID, + HAKUREI_SHIM_BAD_PID, +} hakurei_shim_msg; + void hakurei_shim_setup_cont_signal(pid_t ppid, int fd); diff --git a/internal/outcome/shim.go b/internal/outcome/shim.go index a16bdc7..acc962c 100644 --- a/internal/outcome/shim.go +++ b/internal/outcome/shim.go @@ -22,6 +22,17 @@ import ( //#include "shim-signal.h" import "C" +const ( + /* hakurei requests shim exit */ + shimMsgExitRequested = C.HAKUREI_SHIM_EXIT_REQUESTED + /* shim orphaned before hakurei delivers a signal */ + shimMsgOrphaned = C.HAKUREI_SHIM_ORPHAN + /* unreachable */ + shimMsgInvalid = C.HAKUREI_SHIM_INVALID + /* unexpected si_pid */ + shimMsgBadPID = C.HAKUREI_SHIM_BAD_PID +) + // setupContSignal sets up the SIGCONT signal handler for the cross-uid shim exit hack. // The signal handler is implemented in C, signals can be processed by reading from the returned reader. // The returned function must be called after all signal processing concludes. @@ -161,7 +172,7 @@ func shimEntrypoint(k syscallDispatcher) { } switch buf[0] { - case 0: // got SIGCONT from monitor: shim exit requested + case shimMsgExitRequested: // got SIGCONT from hakurei: shim exit requested if fp := cancelContainer.Load(); stateParams.params.ForwardCancel && fp != nil && *fp != nil { (*fp)() // shim now bound by ShimWaitDelay, implemented below @@ -171,13 +182,13 @@ func shimEntrypoint(k syscallDispatcher) { // setup has not completed, terminate immediately k.exit(hst.ExitRequest) - case 1: // got SIGCONT via pdeath_signal: monitor died before delivering signal + case shimMsgOrphaned: // got SIGCONT after orphaned: hakurei died before delivering signal k.exit(hst.ExitOrphan) - case 2: // unreachable + case shimMsgInvalid: // unreachable msg.Verbose("sa_sigaction got invalid siginfo") - case 3: // got SIGCONT from unexpected process: hopefully the terminal driver + case shimMsgBadPID: // got SIGCONT from unexpected process: hopefully the terminal driver msg.Verbose("got SIGCONT from unexpected process") default: // unreachable diff --git a/internal/outcome/shim_test.go b/internal/outcome/shim_test.go index d493f70..046c22b 100644 --- a/internal/outcome/shim_test.go +++ b/internal/outcome/shim_test.go @@ -148,9 +148,9 @@ func TestShimEntrypoint(t *testing.T) { // deferred call("wKeepAlive", stub.ExpectArgs{}, nil, nil), }, Tracks: []stub.Expect{{Calls: []stub.Call{ - call("rcRead", stub.ExpectArgs{}, []byte{2}, nil), + call("rcRead", stub.ExpectArgs{}, []byte{shimMsgInvalid}, nil), call("verbose", stub.ExpectArgs{[]any{"sa_sigaction got invalid siginfo"}}, nil, nil), - call("rcRead", stub.ExpectArgs{}, []byte{3}, nil), + call("rcRead", stub.ExpectArgs{}, []byte{shimMsgBadPID}, nil), call("verbose", stub.ExpectArgs{[]any{"got SIGCONT from unexpected process"}}, nil, nil), call("rcRead", stub.ExpectArgs{}, nil, nil), // stub terminates this goroutine }}}}, nil},