test: cover sigtest

user/sigtest.c

@@ -0,0 +1,127 @@
+#include "ulib.h"
+
+/*
+ * Boot-time driver for the whole signal-delivery demo (signal.h). Spawns
+ * two independent children -- sigtarget.c (installs a real handler) and
+ * sigdefault.c (installs none) -- and sends each a real signal through the
+ * full syscall path (userSigSend, not a kernel-internal shortcut), proving
+ * both outcomes sigConsumePending can produce: caught-and-resumed, and
+ * uncaught-and-terminated.
+ *
+ * sigtarget needs a real happens-before guarantee, not a sleep guess:
+ * sigUsr1's default disposition is Terminate, so a signal that arrives
+ * before sigtarget's userSigAction has actually run would kill it instead
+ * of being caught -- this was originally "give it 100ms and hope", which
+ * really did fail under host load (sigtarget killed by the uncaught
+ * default before it ever installed its handler). See sigtarget.c for the
+ * shared-pipe rendezvous (fifomaster.c's pattern) that fixes it: this
+ * process blocks on a real read for sigtarget's own "handler installed"
+ * byte before ever calling userSigSend.
+ *
+ * sigdefault has no such window -- its default disposition applies from
+ * the moment it exists, whether or not it has run any code yet -- so a
+ * plain sleep-then-send (mirroring killtest.c's own "give the victim time
+ * to reach its blocking read") is genuinely sufficient there.
+ */
+
+int main(void)
+{
+    print("sigtest: start, pid=");
+    printDec(userGetpid());
+    print("\n");
+
+    if (userSigSend(999999, sigUsr1) != -1) {
+        print("sigtest: FAIL signal to bogus pid should fail\n");
+        return 1;
+    }
+    print("sigtest: signal to bad pid rejected\n");
+
+    if (userSigAction(sigKill, (SigHandler)0, 0, 0) != (long)sigSetFailed) {
+        print("sigtest: FAIL installing a sigKill handler should be rejected\n");
+        return 1;
+    }
+    print("sigtest: sigkill-handler-rejected-ok\n");
+
+    long readyHandle = userPipeCreate();
+    if (readyHandle < 0) {
+        print("sigtest: FAIL create ready pipe\n");
+        return 1;
+    }
+
+    /* Attach as reader BEFORE sigtarget even exists, let alone before it
+       can possibly attach+write+close its own end: pipeCloseWrite (pipe.c)
+       reclaims a detached pipe's slot the moment readers AND writers both
+       read 0, which they still would right after sigtarget's write+close
+       if this process had not attached yet -- observed for real (sigtarget
+       raced ahead, wrote its ready byte, closed, and freed the slot before
+       this process's own attach below ever ran, which then failed outright
+       on the now-invalid handle). Attaching first makes readers==1 from
+       the very start, so that race window never opens. */
+    long readyFd = userPipeAttach(readyHandle, 0);
+    if (readyFd < 0) {
+        print("sigtest: FAIL attach ready pipe\n");
+        return 1;
+    }
+
+    char readyHandleStr[24];
+    decToString(readyHandle, readyHandleStr);
+
+    char* targetArgv[] = { "/bin/sigtarget", readyHandleStr, 0 };
+    long target = userSpawn("/bin/sigtarget", targetArgv);
+    if (target < 0) {
+        print("sigtest: FAIL spawn sigtarget\n");
+        return 1;
+    }
+
+    char readyByte;
+    /* Real blocking read: does not return until sigtarget has actually
+       installed its handler and written this byte (see sigtarget.c) --
+       the happens-before guarantee a fixed userSleep could not give. */
+    if (userRead((int)readyFd, &readyByte, 1) != 1) {
+        print("sigtest: FAIL read ready byte\n");
+        return 1;
+    }
+    userClose((int)readyFd);
+
+    if (userSigSend(target, sigUsr1) != 0) {
+        print("sigtest: FAIL send sigUsr1 to sigtarget\n");
+        return 1;
+    }
+    print("sigtest: sent sigUsr1 to sigtarget\n");
+
+    long status = userWait(target);
+    print("sigtest: sigtarget exit status=");
+    printDec(status);
+    print("\n");
+    if (status != 42) {
+        print("sigtest: FAIL expected sigtarget exit status 42\n");
+        return 1;
+    }
+    print("sigtest: handler-roundtrip-ok\n");
+
+    long defaultTarget = userSpawn("/bin/sigdefault", 0);
+    if (defaultTarget < 0) {
+        print("sigtest: FAIL spawn sigdefault\n");
+        return 1;
+    }
+
+    userSleep(100);
+
+    if (userSigSend(defaultTarget, sigTerm) != 0) {
+        print("sigtest: FAIL send sigTerm to sigdefault\n");
+        return 1;
+    }
+    print("sigtest: sent sigTerm to sigdefault\n");
+
+    long defaultStatus = userWait(defaultTarget);
+    print("sigtest: sigdefault exit status=");
+    printDec(defaultStatus);
+    print("\n");
+    if (defaultStatus != 128 + sigTerm) {
+        print("sigtest: FAIL expected sigdefault exit status 128+sigTerm\n");
+        return 1;
+    }
+    print("sigtest: default-terminate-ok\n");
+
+    return 0;
+}