feat: add streq, printErr and printPadded

user/cwdtarget.c

@@ -0,0 +1,75 @@
+#include "ulib.h"
+
+/*
+ * Only ever spawned by cwdtest.c, with no argv at all -- unlike every other
+ * *test / *target pair in this kernel (which rendezvous over a shared pipe
+ * handle passed as an argv string), this pair's whole point is that the
+ * KERNEL itself hands this process its starting directory at creation time
+ * (sched.c's threadCreate/threadCreateUser, via the new initialCwd helper
+ * that mirrors initialPgid's own "inherit from whoever is currently
+ * running" shape for Thread.pgid), never anything cwdtest.c has to pass
+ * explicitly.
+ *
+ * Proves inheritance first, then proves the inherited value is a real,
+ * independent COPY rather than shared state: this process's own later
+ * chdir() must not reach back into cwdtest.c's Thread.cwd (cwdtest.c's own
+ * post-wait getcwd() check is the other half of that proof).
+ */
+
+static int streq(const char* a, const char* b)
+{
+    while (*a && *a == *b) {
+        a++;
+        b++;
+    }
+    return *a == *b;
+}
+
+int main(void)
+{
+    print("cwdtarget: start, pid=");
+    printDec(userGetpid());
+    print("\n");
+
+    char cwdBuf[64];
+    long len = userGetcwd(cwdBuf, sizeof(cwdBuf));
+    if (len < 0 || !streq(cwdBuf, "/tmp/cwda")) {
+        print("cwdtarget: FAIL inherited cwd, got: ");
+        print(len < 0 ? "(error)" : cwdBuf);
+        print("\n");
+        return 1;
+    }
+    print("cwdtarget: inherited-cwd-ok\n");
+
+    if (userChdir("/tmp/cwdb") != 0) {
+        print("cwdtarget: FAIL chdir /tmp/cwdb\n");
+        return 1;
+    }
+    len = userGetcwd(cwdBuf, sizeof(cwdBuf));
+    if (len < 0 || !streq(cwdBuf, "/tmp/cwdb")) {
+        print("cwdtarget: FAIL getcwd after own chdir, got: ");
+        print(len < 0 ? "(error)" : cwdBuf);
+        print("\n");
+        return 1;
+    }
+
+    /* Relative path again -- must land at /tmp/cwdb/note, a COMPLETELY
+       different file than cwdtest.c's own /tmp/cwda/note despite the
+       identical relative name "note", since each process resolves it
+       against its own Thread.cwd. */
+    int fd = (int)userOpen("note", oCreate | oWriteOnly | oTrunc);
+    if (fd < 0) {
+        print("cwdtarget: FAIL create relative note in cwdb\n");
+        return 1;
+    }
+    const char* payload = "cwdb-payload";
+    unsigned long payloadLen = stringLength(payload);
+    if (userWrite(fd, payload, payloadLen) != (long)payloadLen) {
+        print("cwdtarget: FAIL write relative note in cwdb\n");
+        return 1;
+    }
+    userClose(fd);
+    print("cwdtarget: relative-write-cwdb-ok\n");
+
+    return 0;
+}