user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/tests/rtld/dl_iterate_phdr/libbar.c

@@ -0,0 +1,3 @@
+// Bar needs to have a relocation against foo in order to set DT_NEEDED.
+int foo(void);
+int bar() { return foo(); }

user/include/mlibc/tests/rtld/dl_iterate_phdr/libfoo.c

@@ -0,0 +1 @@
+int foo() { return 0; }

user/include/mlibc/tests/rtld/dl_iterate_phdr/meson.build

@@ -0,0 +1,7 @@
+libfoo = shared_library('foo', 'libfoo.c')
+libbar = shared_library('bar', 'libbar.c', build_rpath: test_rpath, link_with: libfoo)
+test_depends = [libfoo, libbar]
+
+libfoo_native = shared_library('native-foo', 'libfoo.c', native: true)
+libbar_native = shared_library('native-bar', 'libbar.c', build_rpath: test_rpath, link_with: libfoo_native, native: true)
+test_native_depends = [libfoo_native, libbar_native]

user/include/mlibc/tests/rtld/dl_iterate_phdr/test.c

@@ -0,0 +1,91 @@
+#include <assert.h>
+#include <link.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <stdio.h>
+
+#ifdef USE_HOST_LIBC
+#define LDSO_PATTERN "ld-linux-"
+#define LIBFOO "libnative-foo.so"
+#define LIBBAR "libnative-bar.so"
+#else
+#define LDSO_PATTERN "ld.so"
+#define LIBFOO "libfoo.so"
+#define LIBBAR "libbar.so"
+#endif
+
+struct result {
+	int found_ldso;
+	int found_self;
+	int found_foo;
+	int found_bar;
+};
+
+static int ends_with(const char *suffix, const char *s) {
+	size_t suffix_len = strlen(suffix);
+	size_t s_len = strlen(s);
+	if (s_len < suffix_len)
+		return 0;
+	else {
+		return !strcmp(suffix, s + s_len - suffix_len);
+	}
+}
+
+static int contains(const char *pattern, const char *s) {
+	return !!strstr(s, pattern);
+}
+
+static int callback(struct dl_phdr_info *info, size_t size, void *data) {
+	assert(size == sizeof(struct dl_phdr_info));
+	struct result *found = (struct result *) data;
+
+	printf("%s\n", info->dlpi_name);
+	fflush(stdout);
+
+	if (ends_with("foo.so", info->dlpi_name))
+		found->found_foo++;
+	if (ends_with("bar.so", info->dlpi_name))
+		found->found_bar++;
+	if (contains(LDSO_PATTERN, info->dlpi_name))
+		found->found_ldso++;
+
+	if (!strcmp("", info->dlpi_name))
+		found->found_self++;
+
+	assert(info->dlpi_phdr);
+	return 0;
+}
+
+int main() {
+	struct result found = { 0 };
+	assert(!dl_iterate_phdr(callback, &found));
+	assert(found.found_ldso == 1);
+	assert(found.found_self == 1);
+	assert(found.found_foo == 0);
+	assert(found.found_bar == 0);
+	printf("---\n");
+
+	memset(&found, 0, sizeof(found));
+	void *bar = dlopen(LIBBAR, RTLD_LOCAL | RTLD_NOW);
+	assert(bar);
+	assert(!dl_iterate_phdr(callback, &found));
+	assert(found.found_ldso == 1);
+	assert(found.found_self == 1);
+	assert(found.found_bar == 1);
+	assert(found.found_foo == 1); // Since bar depends on foo.
+	printf("---\n");
+
+	memset(&found, 0, sizeof(found));
+	void *foo = dlopen(LIBFOO, RTLD_GLOBAL | RTLD_NOW);
+	assert(foo);
+	assert(!dl_iterate_phdr(callback, &found));
+	assert(found.found_ldso == 1);
+	assert(found.found_self == 1);
+	assert(found.found_foo == 1);
+	assert(found.found_bar == 1);
+	printf("---\n");
+
+	dlclose(bar);
+	dlclose(foo);
+	return 0;
+}