selftests/nolibc: add testcases for startup code

The startup code is critical to get the right argc, argv, envp/environ
and _auxv, let's add a startup test group and the corresponding
testcases.

The "environ" test case is also moved from the stdlib test group to this
new startup test group and it is renamed to "environ_envp".

Since argv0 has been used by many other test cases, let's add testcases
to gurantee it too.
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

tools/testing/selftests/nolibc/nolibc-test.c

@@ -15,6 +15,7 @@
 #include <string.h>
 #ifndef _NOLIBC_STDIO_H
 /* standard libcs need more includes */
+#include <sys/auxv.h>
 #include <sys/io.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
@@ -47,6 +48,12 @@
 /* will be used to test initialization of environ */
 static char **test_envp;
 
+/* will be used to test initialization of argv */
+static char **test_argv;
+
+/* will be used to test initialization of argc */
+static int test_argc;
+
 /* will be used by some test cases as readable file, please don't write it */
 static const char *argv0;
 
@@ -561,6 +568,51 @@ static int expect_strne(const char *expr, int llen, const char *cmp)
 #define CASE_TEST(name) \
 	case __LINE__: llen += printf("%d %s", test, #name);
 
+int run_startup(int min, int max)
+{
+	int test;
+	int ret = 0;
+	/* kernel at least passes HOME and TERM, shell passes more */
+	int env_total = 2;
+	/* checking NULL for argv/argv0, environ and _auxv is not enough, let's compare with sbrk(0) or &end */
+	extern char end;
+	char *brk = sbrk(0) != (void *)-1 ? sbrk(0) : &end;
+	/* differ from nolibc, both glibc and musl have no global _auxv */
+	const unsigned long *test_auxv = (void *)-1;
+#ifdef NOLIBC
+	test_auxv = _auxv;
+#endif
+
+	for (test = min; test >= 0 && test <= max; test++) {
+		int llen = 0; /* line length */
+
+		/* avoid leaving empty lines below, this will insert holes into
+		 * test numbers.
+		 */
+		switch (test + __LINE__ + 1) {
+		CASE_TEST(argc);             EXPECT_GE(1, test_argc, 1); break;
+		CASE_TEST(argv_addr);        EXPECT_PTRGT(1, test_argv, brk); break;
+		CASE_TEST(argv_environ);     EXPECT_PTRLT(1, test_argv, environ); break;
+		CASE_TEST(argv_total);       EXPECT_EQ(1, environ - test_argv - 1, test_argc ?: 1); break;
+		CASE_TEST(argv0_addr);       EXPECT_PTRGT(1, argv0, brk); break;
+		CASE_TEST(argv0_str);        EXPECT_STRNZ(1, argv0 > brk ? argv0 : NULL); break;
+		CASE_TEST(argv0_len);        EXPECT_GE(1,  argv0 > brk ? strlen(argv0) : 0, 1); break;
+		CASE_TEST(environ_addr);     EXPECT_PTRGT(1, environ, brk); break;
+		CASE_TEST(environ_envp);     EXPECT_PTREQ(1, environ, test_envp); break;
+		CASE_TEST(environ_auxv);     EXPECT_PTRLT(test_auxv != (void *)-1, environ, test_auxv); break;
+		CASE_TEST(environ_total);    EXPECT_GE(test_auxv != (void *)-1, (void *)test_auxv - (void *)environ - 1, env_total); break;
+		CASE_TEST(environ_HOME);     EXPECT_PTRNZ(1, getenv("HOME")); break;
+		CASE_TEST(auxv_addr);        EXPECT_PTRGT(test_auxv != (void *)-1, test_auxv, brk); break;
+		CASE_TEST(auxv_AT_UID);      EXPECT_EQ(1, getauxval(AT_UID), getuid()); break;
+		CASE_TEST(auxv_AT_PAGESZ);   EXPECT_GE(1, getauxval(AT_PAGESZ), 4096); break;
+		case __LINE__:
+			return ret; /* must be last */
+		/* note: do not set any defaults so as to permit holes above */
+		}
+	}
+	return ret;
+}
+
 
 /* used by some syscall tests below */
 int test_getdents64(const char *dir)
@@ -845,7 +897,6 @@ int run_stdlib(int min, int max)
 		 * test numbers.
 		 */
 		switch (test + __LINE__ + 1) {
-		CASE_TEST(environ);            EXPECT_PTREQ(1, environ, test_envp); break;
 		CASE_TEST(getenv_TERM);        EXPECT_STRNZ(1, getenv("TERM")); break;
 		CASE_TEST(getenv_blah);        EXPECT_STRZR(1, getenv("blah")); break;
 		CASE_TEST(setcmp_blah_blah);   EXPECT_EQ(1, strcmp("blah", "blah"), 0); break;
@@ -1129,6 +1180,7 @@ int prepare(void)
 /* This is the definition of known test names, with their functions */
 static const struct test test_names[] = {
 	/* add new tests here */
+	{ .name = "startup",    .func = run_startup    },
 	{ .name = "syscall",    .func = run_syscall    },
 	{ .name = "stdlib",     .func = run_stdlib     },
 	{ .name = "vfprintf",   .func = run_vfprintf   },
@@ -1175,6 +1227,8 @@ int main(int argc, char **argv, char **envp)
 	char *test;
 
 	argv0 = argv[0];
+	test_argc = argc;
+	test_argv = argv;
 	test_envp = envp;
 
 	/* when called as init, it's possible that no console was opened, for