[libc] Add strlcat

Differential Revision: https://reviews.llvm.org/D125978

12 files changed, 130 insertions, 12 deletions

diff --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
index 568a8fb..a8f882f 100644
--- a/libc/config/darwin/arm/entrypoints.txt
+++ b/libc/config/darwin/arm/entrypoints.txt
@@ -35,6 +35,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strcmp
     libc.src.string.strcpy
     libc.src.string.strcspn
+    libc.src.string.strlcat
     libc.src.string.strlcpy
     libc.src.string.strlen
     libc.src.string.strncat
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 31a5969..01b4fac 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -40,6 +40,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strcmp
     libc.src.string.strcpy
     libc.src.string.strcspn
+    libc.src.string.strlcat
     libc.src.string.strlcpy
     libc.src.string.strlen
     libc.src.string.strncat
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 783dabf..a0b7a6b5 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -40,6 +40,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strcmp
     libc.src.string.strcpy
     libc.src.string.strcspn
+    libc.src.string.strlcat
     libc.src.string.strlcpy
     libc.src.string.strlen
     libc.src.string.strncat
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index 0f5b14a..8d7cf67 100644
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -35,6 +35,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.strcmp
     libc.src.string.strcpy
     libc.src.string.strcspn
+    libc.src.string.strlcat
     libc.src.string.strlcpy
     libc.src.string.strlen
     libc.src.string.strncat
diff --git a/libc/spec/bsd_ext.td b/libc/spec/bsd_ext.td
index 09832f7..577d978 100644
--- a/libc/spec/bsd_ext.td
+++ b/libc/spec/bsd_ext.td
@@ -6,6 +6,11 @@ def BsdExtensions : StandardSpec<"BSDExtensions"> {
       [], // Enumerations
       [ 
         FunctionSpec<
+            "strlcat",
+            RetValSpec<SizeTType>,
+            [ArgSpec<CharPtr>, ArgSpec<ConstCharPtr>, ArgSpec<SizeTType>]
+        >,
+        FunctionSpec<
             "strlcpy",
             RetValSpec<SizeTType>,
             [ArgSpec<CharPtr>, ArgSpec<ConstCharPtr>, ArgSpec<SizeTType>]
diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
index 20b1b4c..68962e2 100644
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -6,6 +6,8 @@ add_header_library(
     string_utils.h
   DEPENDS
     libc.src.__support.CPP.bitset
+    .memory_utils.memcpy_implementation
+    .memory_utils.memset_implementation
 )
 
 add_entrypoint_object(
@@ -127,14 +129,23 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  strlcat
+  SRCS
+    strlcat.cpp
+  HDRS
+    strlcat.h
+  DEPENDS
+    .string_utils
+    libc.include.string
+)
+
+add_entrypoint_object(
   strlcpy
   SRCS
     strlcpy.cpp
   HDRS
     strlcpy.h
   DEPENDS
-    .memory_utils.memcpy_implementation
-    .memory_utils.memset_implementation
     .string_utils
     libc.include.string
 )
diff --git a/libc/src/string/string_utils.h b/libc/src/string/string_utils.h
index 699f65f..3d854d3 100644
--- a/libc/src/string/string_utils.h
+++ b/libc/src/string/string_utils.h
@@ -11,6 +11,8 @@
 
 #include "src/__support/CPP/Bitset.h"
 #include "src/__support/common.h"
+#include "src/string/memory_utils/memcpy_implementations.h"
+#include "src/string/memory_utils/memset_implementations.h"
 #include <stddef.h> // size_t
 
 namespace __llvm_libc {
@@ -85,6 +87,17 @@ static inline char *string_token(char *__restrict src,
   return token;
 }
 
+static inline size_t strlcpy(char *__restrict dst, const char *__restrict src,
+                             size_t size) {
+  size_t len = internal::string_length(src);
+  if (!size)
+    return len;
+  size_t n = len < size - 1 ? len : size - 1;
+  inline_memcpy(dst, src, n);
+  inline_memset(dst + n, 0, size - n);
+  return len;
+}
+
 } // namespace internal
 } // namespace __llvm_libc
 
diff --git a/libc/src/string/strlcat.cpp b/libc/src/string/strlcat.cpp
new file mode 100644
index 0000000..a718de7
--- /dev/null
+++ b/libc/src/string/strlcat.cpp
@@ -0,0 +1,27 @@
+//===-- Implementation of strlcat -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/string/strlcat.h"
+#include "src/string/string_utils.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(size_t, strlcat,
+                   (char *__restrict dst, const char *__restrict src,
+                    size_t size)) {
+  char *new_dst = reinterpret_cast<char *>(internal::find_first_character(
+      reinterpret_cast<unsigned char *>(dst), 0, size));
+  if (!new_dst)
+    return size + internal::string_length(src);
+  size_t first_len = new_dst - dst;
+  return first_len + internal::strlcpy(new_dst, src, size - first_len);
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/string/strlcat.h b/libc/src/string/strlcat.h
new file mode 100644
index 0000000..7b073c6
--- /dev/null
+++ b/libc/src/string/strlcat.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for strlcat -----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_STRING_STRLCAT_H
+#define LLVM_LIBC_SRC_STRING_STRLCAT_H
+
+#include <string.h>
+
+namespace __llvm_libc {
+
+size_t strlcat(char *__restrict dst, const char *__restrict src, size_t size);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STRING_STRLCAT_H
diff --git a/libc/src/string/strlcpy.cpp b/libc/src/string/strlcpy.cpp
index 3cb3dd1..fa1f102 100644
--- a/libc/src/string/strlcpy.cpp
+++ b/libc/src/string/strlcpy.cpp
@@ -7,9 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/string/strlcpy.h"
-#include "src/string/bzero.h"
-#include "src/string/memory_utils/memcpy_implementations.h"
-#include "src/string/memory_utils/memset_implementations.h"
 #include "src/string/string_utils.h"
 
 #include "src/__support/common.h"
@@ -19,13 +16,7 @@ namespace __llvm_libc {
 LLVM_LIBC_FUNCTION(size_t, strlcpy,
                    (char *__restrict dst, const char *__restrict src,
                     size_t size)) {
-  size_t len = internal::string_length(src);
-  if (!size)
-    return len;
-  size_t n = len < size - 1 ? len : size - 1;
-  inline_memcpy(dst, src, n);
-  inline_memset(dst + n, 0, size - n);
-  return len;
+  return internal::strlcpy(dst, src, size);
 }
 
 } // namespace __llvm_libc
diff --git a/libc/test/src/string/CMakeLists.txt b/libc/test/src/string/CMakeLists.txt
index 5bdb47a..e60f9ab 100644
--- a/libc/test/src/string/CMakeLists.txt
+++ b/libc/test/src/string/CMakeLists.txt
@@ -124,6 +124,16 @@ add_libc_unittest(
 )
 
 add_libc_unittest(
+  strlcat_test
+  SUITE
+    libc_string_unittests
+  SRCS
+    strlcat_test.cpp
+  DEPENDS
+    libc.src.string.strlcat
+)
+
+add_libc_unittest(
   strlcpy_test
   SUITE
     libc_string_unittests
diff --git a/libc/test/src/string/strlcat_test.cpp b/libc/test/src/string/strlcat_test.cpp
new file mode 100644
index 0000000..66db15e5
--- /dev/null
+++ b/libc/test/src/string/strlcat_test.cpp
@@ -0,0 +1,37 @@
+//===-- Unittests for strlcat ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/string/strlcat.h"
+#include "utils/UnitTest/Test.h"
+#include <stdlib.h>
+
+TEST(LlvmLibcStrlcatTest, TooBig) {
+  const char *str = "cd";
+  char buf[4]{"ab"};
+  EXPECT_EQ(__llvm_libc::strlcat(buf, str, 3), size_t(4));
+  EXPECT_STREQ(buf, "ab");
+  EXPECT_EQ(__llvm_libc::strlcat(buf, str, 4), size_t(4));
+  EXPECT_STREQ(buf, "abc");
+}
+
+TEST(LlvmLibcStrlcatTest, Smaller) {
+  const char *str = "cd";
+  char buf[7]{"ab"};
+
+  EXPECT_EQ(__llvm_libc::strlcat(buf, str, 7), size_t(4));
+  EXPECT_STREQ(buf, "abcd");
+}
+
+TEST(LlvmLibcStrlcatTest, No0) {
+  const char *str = "cd";
+  char buf[7]{"ab"};
+  EXPECT_EQ(__llvm_libc::strlcat(buf, str, 1), size_t(3));
+  EXPECT_STREQ(buf, "ab");
+  EXPECT_EQ(__llvm_libc::strlcat(buf, str, 2), size_t(4));
+  EXPECT_STREQ(buf, "ab");
+}