test: cover streq

user/argtest.c

@@ -0,0 +1,47 @@
+#include "ulib.h"
+
+/*
+ * Exercises argv/argc plumbing added this wave (elfBuildInitialStack in
+ * elf.c, copyUserArgv in syscall.c, crt.S's _start now reading argc/argv
+ * off the initial stack instead of calling main() with nothing). Only ever
+ * spawned by proctest.c, with a specific, known argv -- if the kernel-side
+ * stack layout is wrong in any way (misaligned rsp, wrong argc, a string
+ * copied to the wrong address, an argv[i] pointer landing on garbage),
+ * these comparisons catch it directly instead of a lucky match papering
+ * over a bug. userspace has no libc string.h, so the comparison is spelled
+ * out by hand exactly the way spawntarget.c/proctest.c already avoid
+ * pulling in anything beyond ulib.h.
+ */
+
+static int streq(const char* a, const char* b)
+{
+    while (*a && *a == *b) {
+        a++;
+        b++;
+    }
+    return *a == *b;
+}
+
+int main(int argc, char** argv)
+{
+    print("argtest: argc=");
+    printDec(argc);
+    print("\n");
+
+    for (int i = 0; i < argc; i++) {
+        print("argtest: argv[");
+        printDec(i);
+        print("]=");
+        print(argv[i]);
+        print("\n");
+    }
+
+    int ok = argc == 4 &&
+        streq(argv[0], "/bin/argtest") &&
+        streq(argv[1], "alpha") &&
+        streq(argv[2], "beta") &&
+        streq(argv[3], "gamma");
+
+    print(ok ? "argtest: argv-ok\n" : "argtest: argv-FAIL\n");
+    return ok ? 0 : 1;
+}