Improve symlink tests

Instead of crashing on the first failed test, log an error message for
each failed test that points to the location of the error.

(cherry picked from commit 5dcc596)

qrexec-lib/validator-test.c

@@ -119,23 +119,54 @@ int main(int argc, char **argv)
                (always_forbidden || bad_unicode ? -EILSEQ : 0));
     }
 
-    // Symbolic links
-    // Top level cannot be symlink
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"a", (const uint8_t *)"b"));
-    // Symbolic links cannot escape
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"a/b", (const uint8_t *)"../a"));
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"a/b", (const uint8_t *)"../a/b/c"));
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"a/b/c", (const uint8_t *)"../../a"));
-    assert(qubes_pure_validate_symbolic_link((const uint8_t *)"a/b", (const uint8_t *)"a"));
-    assert(qubes_pure_validate_symbolic_link((const uint8_t *)"a/b/c", (const uint8_t *)"../a"));
-    // Absolute symlinks are rejected
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"a/b/c", (const uint8_t *)"/a"));
-    // Symlinks may end in "..".
-    assert(qubes_pure_validate_symbolic_link((const uint8_t *)"a/b/c", (const uint8_t *)".."));
-    // Symlinks may end in "/".
-    assert(qubes_pure_validate_symbolic_link((const uint8_t *)"a/b/c", (const uint8_t *)"a/"));
-    // Symlinks reject invalid paths.
-    assert(!qubes_pure_validate_symbolic_link((const uint8_t *)"..", (const uint8_t *)"a/"));
+    struct p {
+        const char *const path, *const target, *const file;
+        int const line, flags;
+        bool const allowed;
+    } symlink_checks[] = {
+#define TEST(path_, target_, flags_, allowed_) \
+        { .path = (path_)                      \
+        , .target = (target_)                  \
+        , .file = __FILE__                     \
+        , .line = __LINE__                     \
+        , .flags = (flags_)                    \
+        , .allowed = (allowed_)                \
+        }
+        // Symbolic links
+        // Top level cannot be symlink
+        TEST("a", "b", 0, false),
+        TEST("a/b", "../a", 0, false),
+        TEST("a", "b", 0, false),
+        // Symbolic links cannot escape
+        TEST("a/b", "../a", 0, false),
+        TEST("a/b", "../a", 0, false),
+        TEST("a/b", "../a/b/c", 0, false),
+        TEST("a/b", "../a/b/c", 0, false),
+        TEST("a/b/c", "../../a", 0, false),
+        TEST("a/b/c", "../../a", 0, false),
+        TEST("a/b", "a", 0, true),
+        TEST("a/b/c", "../a", 0, true),
+        // Absolute symlinks are rejected
+        TEST("a/b/c", "/a", 0, false),
+        TEST("a/b/c", "/a", 0, false),
+        // Symlinks may end in "..".
+        TEST("a/b/c", "..", 0, true),
+        // Symlinks may end in "/".
+        TEST("a/b/c", "a/", 0, true),
+        // Invalid paths are rejected.
+        TEST("..", "a/", 0, false),
+    };
+    bool failed = false;
+    for (size_t i = 0; i < sizeof(symlink_checks)/sizeof(symlink_checks[0]); ++i) {
+        const struct p *p = symlink_checks + i;
+        if ((qubes_pure_validate_symbolic_link_v2((const unsigned char *)p->path,
+                                                  (const unsigned char *)p->target,
+                                                  p->flags) == 0) != p->allowed) {
+            failed = true;
+            fprintf(stderr, "%s:%d:Test failure\n", p->file, p->line);
+        }
+    }
+    assert(!failed);
 
     // Greek letters are safe
     assert(qubes_pure_validate_file_name((uint8_t *)u8"\u03b2.txt"));