test: cover proctest and restarttest

user/proctest.c

@@ -0,0 +1,83 @@
+#include "ulib.h"
+
+/*
+ * Exercises the process-management syscalls added this wave: sysSpawn
+ * (posix_spawn()-lite -- loads a binary into a brand new thread) and
+ * sysWait (threadJoin, sched.c/sched.h) together, then sysExec (execve()-
+ * lite -- replaces this very process's image in place, see syscall.c
+ * doExec). Split across two helper binaries deliberately: spawntarget.c is
+ * only ever spawned (never exec'd), exectarget.c is only ever exec'd
+ * (never spawned) -- frostbyte has one shared address space system-wide
+ * (paging.c has a single page table, no per-process CR3), so two binaries
+ * whose fixed link addresses collide can never be genuinely live at the
+ * same time. Keeping "the spawn target" and "the exec target" as distinct
+ * binaries, and waiting for the spawned child before ever calling exec,
+ * means this test never asks the kernel to do something the architecture
+ * cannot support.
+ *
+ * This function never returns on its own success path: the final call is
+ * userExec("/bin/exectarget"), which -- if the syscall does its job --
+ * replaces this thread's own code/stack/pid identity with exectarget's, so
+ * "proctest" never gets to print anything past that call. kmain.c's
+ * execReaperThread separately threadJoin()s this same pid and checks it
+ * eventually reports exectarget's exit code, which is the only way to
+ * observe that the exec() actually happened from outside this process.
+ */
+
+int main(void)
+{
+    print("proctest: start, pid=");
+    printDec(userGetpid());
+    print("\n");
+
+    long child = userSpawn("/bin/spawntarget", 0);
+    if (child < 0) {
+        print("proctest: FAIL spawn /bin/spawntarget\n");
+        return 1;
+    }
+
+    long status = userWait(child);
+    if (status != 3) {
+        print("proctest: FAIL wait returned unexpected status\n");
+        return 1;
+    }
+    print("proctest: spawn+wait ok\n");
+
+    if (userSpawn("/bin/does-not-exist", 0) != -1) {
+        print("proctest: FAIL spawn of missing binary should fail\n");
+        return 1;
+    }
+    print("proctest: spawn bad path rejected\n");
+
+    if (userWait(999999) != -1) {
+        print("proctest: FAIL wait on bogus pid should fail immediately\n");
+        return 1;
+    }
+    print("proctest: wait bad pid rejected\n");
+
+    /* argtest.c checks its own argc/argv against exactly this list --
+       proves the whole chain (copyUserArgv copying these out of THIS
+       process's memory, elfBuildInitialStack laying them onto the child's
+       brand new stack, crt.S's _start reading them back off of it) rather
+       than just that spawn/wait still works with a null argv. */
+    char* argtestArgv[] = { "/bin/argtest", "alpha", "beta", "gamma", 0 };
+    long argChild = userSpawn("/bin/argtest", argtestArgv);
+    if (argChild < 0) {
+        print("proctest: FAIL spawn /bin/argtest\n");
+        return 1;
+    }
+
+    long argStatus = userWait(argChild);
+    if (argStatus != 0) {
+        print("proctest: FAIL argtest reported bad argv\n");
+        return 1;
+    }
+    print("proctest: spawn with argv ok\n");
+
+    userExec("/bin/exectarget", 0);
+
+    /* Only reached if userExec failed outright (bad path, load failure) --
+       a successful exec never returns here at all. */
+    print("proctest: FAIL exec did not take over\n");
+    return 1;
+}