LibC: Stub and test strlcpy

Libraries/LibC/string.cpp

@@ -214,6 +214,14 @@ char* strncpy(char* dest, const char* src, size_t n)
     return dest;
 }
 
+size_t strlcpy(char* dest, const char* src, size_t n)
+{
+    (void)dest;
+    (void)src;
+    (void)n;
+    return 42; // TODO
+}
+
 char* strchr(const char* str, int c)
 {
     char ch = c;

Libraries/LibC/string.h

@@ -48,6 +48,7 @@ void* memset(void*, int, size_t);
 __attribute__((malloc)) char* strdup(const char*);
 __attribute__((malloc)) char* strndup(const char*, size_t);
 char* strcpy(char* dest, const char* src);
+size_t strlcpy(char* dest, const char* src, size_t);
 char* strncpy(char* dest, const char* src, size_t);
 char* strchr(const char*, int c);
 char* strchrnul(const char*, int c);

Userland/Tests/LibC/strlcpy-correctness.cpp

@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2020, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/TestSuite.h>
+
+#include <AK/ByteBuffer.h>
+#include <AK/Random.h>
+#include <AK/StringBuilder.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+
+struct Testcase {
+    const char* dest;
+    size_t dest_n;
+    const char* src;
+    size_t src_n;
+    const char* dest_expected;
+    size_t dest_expected_n; // == dest_n
+};
+
+static String show(const ByteBuffer& buf)
+{
+    StringBuilder builder;
+    for (size_t i = 0; i < buf.size(); ++i) {
+        builder.appendf("%02x", buf[i]);
+    }
+    builder.append(' ');
+    builder.append('(');
+    for (size_t i = 0; i < buf.size(); ++i) {
+        if (isprint(buf[i]))
+            builder.append(buf[i]);
+        else
+            builder.append('_');
+    }
+    builder.append(')');
+    return builder.build();
+}
+
+static const size_t SANDBOX_CANARY_SIZE = 8;
+
+static bool test_single(const Testcase& testcase)
+{
+    // Preconditions:
+    if (testcase.dest_n != testcase.dest_expected_n) {
+        fprintf(stderr, "dest length %zu != expected dest length %zu? Check testcase! (Probably miscounted.)\n",
+            testcase.dest_n, testcase.dest_expected_n);
+        return false;
+    }
+    if (testcase.src_n != strlen(testcase.src)) {
+        fprintf(stderr, "src length %zu != actual src length %zu? src can't contain NUL bytes!\n",
+            testcase.src_n, strlen(testcase.src));
+        return false;
+    }
+
+    // Setup
+    ByteBuffer actual = ByteBuffer::create_uninitialized(SANDBOX_CANARY_SIZE + testcase.dest_n + SANDBOX_CANARY_SIZE);
+    AK::fill_with_random(actual.data(), actual.size());
+    ByteBuffer expected = actual.isolated_copy();
+    ASSERT(actual.offset_pointer(0) != expected.offset_pointer(0));
+    actual.overwrite(SANDBOX_CANARY_SIZE, testcase.dest, testcase.dest_n);
+    expected.overwrite(SANDBOX_CANARY_SIZE, testcase.dest_expected, testcase.dest_expected_n);
+    // "unsigned char" != "char", so we have to convince the compiler to allow this.
+    char* dst = reinterpret_cast<char*>(actual.offset_pointer(SANDBOX_CANARY_SIZE));
+
+    // The actual call:
+    size_t actual_return = strlcpy(dst, testcase.src, testcase.dest_n);
+
+    // Checking the results:
+    bool return_ok = actual_return == testcase.src_n;
+    bool canary_1_ok = actual.slice_view(0, SANDBOX_CANARY_SIZE) == expected.slice_view(0, SANDBOX_CANARY_SIZE);
+    bool main_ok = actual.slice_view(SANDBOX_CANARY_SIZE, testcase.dest_n) == expected.slice_view(SANDBOX_CANARY_SIZE, testcase.dest_n);
+    bool canary_2_ok = actual.slice_view(SANDBOX_CANARY_SIZE + testcase.dest_n, SANDBOX_CANARY_SIZE) == expected.slice_view(SANDBOX_CANARY_SIZE + testcase.dest_n, SANDBOX_CANARY_SIZE);
+    bool buf_ok = actual == expected;
+
+    // Evaluate gravity:
+    if (buf_ok && (!canary_1_ok || !main_ok || !canary_2_ok)) {
+        fprintf(stderr, "Internal error! (%d != %d | %d | %d)\n",
+            buf_ok, canary_1_ok, main_ok, canary_2_ok);
+        buf_ok = false;
+    }
+    if (!canary_1_ok) {
+        warn() << "Canary 1 overwritten: Expected canary "
+               << show(expected.slice_view(0, SANDBOX_CANARY_SIZE))
+               << ", got "
+               << show(actual.slice_view(0, SANDBOX_CANARY_SIZE))
+               << " instead!";
+    }
+    if (!main_ok) {
+        warn() << "Wrong output: Expected "
+               << show(expected.slice_view(SANDBOX_CANARY_SIZE, testcase.dest_n))
+               << "\n          instead, got " // visually align
+               << show(actual.slice_view(SANDBOX_CANARY_SIZE, testcase.dest_n));
+    }
+    if (!canary_2_ok) {
+        warn() << "Canary 2 overwritten: Expected "
+               << show(expected.slice_view(SANDBOX_CANARY_SIZE + testcase.dest_n, SANDBOX_CANARY_SIZE))
+               << ", got "
+               << show(actual.slice_view(SANDBOX_CANARY_SIZE + testcase.dest_n, SANDBOX_CANARY_SIZE))
+               << " instead!";
+    }
+    if (!return_ok) {
+        fprintf(stderr, "Wrong return value: Expected %zu, got %zu instead!\n",
+            testcase.src_n, actual_return);
+    }
+
+    return buf_ok && return_ok;
+}
+
+// Drop the NUL terminator added by the C++ compiler.
+#define LITERAL(x) x, (sizeof(x) - 1)
+
+//static Testcase TESTCASES[] = {
+//    // Golden path:
+
+//    // Hitting the border:
+
+//    // Too long:
+//    { LITERAL("Hello World!\0"), LITERAL("Hello Friend!"), LITERAL("Hello Friend\0") },
+//    { LITERAL("Hello World!\0"), LITERAL("This source is just *way* too long!"), LITERAL("This source \0") },
+//    { LITERAL("x"), LITERAL("This source is just *way* too long!"), LITERAL("\0") },
+//    // Other special cases:
+//    { LITERAL(""), LITERAL(""), LITERAL("") },
+//    { LITERAL(""), LITERAL("Empty test"), LITERAL("") },
+//    { LITERAL("x"), LITERAL(""), LITERAL("\0") },
+//    { LITERAL("xx"), LITERAL(""), LITERAL("\0x") },
+//    { LITERAL("xxx"), LITERAL(""), LITERAL("\0xx") },
+//};
+
+TEST_CASE(golden_path)
+{
+    EXPECT(test_single({ LITERAL("Hello World!\0\0\0"), LITERAL("Hello Friend!"), LITERAL("Hello Friend!\0\0") }));
+    EXPECT(test_single({ LITERAL("Hello World!\0\0\0"), LITERAL("Hello Friend!"), LITERAL("Hello Friend!\0\0") }));
+    EXPECT(test_single({ LITERAL("aaaaaaaaaa"), LITERAL("whf"), LITERAL("whf\0aaaaaa") }));
+}
+
+TEST_CASE(exact_fit)
+{
+    EXPECT(test_single({ LITERAL("Hello World!\0\0"), LITERAL("Hello Friend!"), LITERAL("Hello Friend!\0") }));
+    EXPECT(test_single({ LITERAL("AAAA"), LITERAL("aaa"), LITERAL("aaa\0") }));
+}
+
+TEST_CASE(off_by_one)
+{
+    EXPECT(test_single({ LITERAL("AAAAAAAAAA"), LITERAL("BBBBB"), LITERAL("BBBBB\0AAAA") }));
+    EXPECT(test_single({ LITERAL("AAAAAAAAAA"), LITERAL("BBBBBBBCC"), LITERAL("BBBBBBBCC\0") }));
+    EXPECT(test_single({ LITERAL("AAAAAAAAAA"), LITERAL("BBBBBBBCCX"), LITERAL("BBBBBBBCC\0") }));
+    EXPECT(test_single({ LITERAL("AAAAAAAAAA"), LITERAL("BBBBBBBCCXY"), LITERAL("BBBBBBBCC\0") }));
+}
+
+TEST_CASE(nearly_empty)
+{
+    EXPECT(test_single({ LITERAL(""), LITERAL(""), LITERAL("") }));
+    EXPECT(test_single({ LITERAL(""), LITERAL("Empty test"), LITERAL("") }));
+    EXPECT(test_single({ LITERAL("x"), LITERAL(""), LITERAL("\0") }));
+    EXPECT(test_single({ LITERAL("xx"), LITERAL(""), LITERAL("\0x") }));
+    EXPECT(test_single({ LITERAL("x"), LITERAL("y"), LITERAL("\0") }));
+}
+
+static char* const POISON = (char*)1;
+TEST_CASE(to_nullptr)
+{
+    EXPECT_EQ(0u, strlcpy(POISON, "", 0));
+    EXPECT_EQ(1u, strlcpy(POISON, "x", 0));
+    EXPECT(test_single({ LITERAL("Hello World!\0\0\0"), LITERAL("Hello Friend!"), LITERAL("Hello Friend!\0\0") }));
+    EXPECT(test_single({ LITERAL("aaaaaaaaaa"), LITERAL("whf"), LITERAL("whf\0aaaaaa") }));
+}
+
+TEST_MAIN(Sprintf)