[libc] implement inet_addr (#167708)

This patch adds the posix function `inet_addr`. Since most of the
parsing logic is delegated to `inet_aton`, I have only included some
basic smoke tests for testing purposes.

libc/config/linux/aarch64/entrypoints.txt

@@ -945,6 +945,7 @@ if(LLVM_LIBC_FULL_BUILD)
     # arpa/inet.h entrypoints
     libc.src.arpa.inet.htonl
     libc.src.arpa.inet.htons
+    libc.src.arpa.inet.inet_addr
     libc.src.arpa.inet.inet_aton
     libc.src.arpa.inet.ntohl
     libc.src.arpa.inet.ntohs

libc/config/linux/riscv/entrypoints.txt

@@ -1078,6 +1078,7 @@ if(LLVM_LIBC_FULL_BUILD)
     # arpa/inet.h entrypoints
     libc.src.arpa.inet.htonl
     libc.src.arpa.inet.htons
+    libc.src.arpa.inet.inet_addr
     libc.src.arpa.inet.inet_aton
     libc.src.arpa.inet.ntohl
     libc.src.arpa.inet.ntohs

libc/config/linux/x86_64/entrypoints.txt

@@ -1119,6 +1119,7 @@ if(LLVM_LIBC_FULL_BUILD)
     # arpa/inet.h entrypoints
     libc.src.arpa.inet.htonl
     libc.src.arpa.inet.htons
+    libc.src.arpa.inet.inet_addr
     libc.src.arpa.inet.inet_aton
     libc.src.arpa.inet.ntohl
     libc.src.arpa.inet.ntohs

libc/include/arpa/inet.yaml

@@ -3,6 +3,7 @@ header_template: inet.h.def
 macros: []
 types:
   - type_name: in_addr
+  - type_name: in_addr_t
 enums: []
 objects: []
 functions:
@@ -18,6 +19,12 @@ functions:
     return_type: uint16_t
     arguments:
       - type: uint16_t
+  - name: inet_addr
+    standards:
+      - POSIX
+    return_type: in_addr_t
+    arguments:
+      - type: const char *
   - name: inet_aton
     standards:
       - llvm_libc_ext

libc/include/llvm-libc-macros/netinet-in-macros.h

@@ -29,6 +29,7 @@
 
 #define INADDR_ANY __LLVM_LIBC_CAST(static_cast, in_addr_t, 0x00000000)
 #define INADDR_BROADCAST __LLVM_LIBC_CAST(static_cast, in_addr_t, 0xffffffff)
+#define INADDR_NONE __LLVM_LIBC_CAST(static_cast, in_addr_t, 0xffffffff)
 
 #define INET_ADDRSTRLEN 16
 #define INET6_ADDRSTRLEN 46

libc/src/arpa/inet/CMakeLists.txt

@@ -35,6 +35,21 @@ add_entrypoint_object(
     libc.src.__support.str_to_integer
 )
 
+add_entrypoint_object(
+  inet_addr
+  SRCS
+    inet_addr.cpp
+  HDRS
+    inet_addr.h
+  DEPENDS
+    libc.include.arpa_inet
+    libc.include.llvm-libc-macros.netinet_in_macros
+    libc.include.llvm-libc-types.in_addr
+    libc.include.llvm-libc-types.in_addr_t
+    libc.src.__support.common
+    libc.src.arpa.inet.inet_aton
+)
+
 add_entrypoint_object(
   ntohl
   SRCS

libc/src/arpa/inet/inet_addr.cpp

@@ -0,0 +1,23 @@
+//===-- Implementation of inet_addr function ------------------------------===//
+//
+// 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/arpa/inet/inet_addr.h"
+#include "include/llvm-libc-macros/netinet-in-macros.h"
+#include "include/llvm-libc-types/in_addr.h"
+#include "include/llvm-libc-types/in_addr_t.h"
+#include "src/__support/common.h"
+#include "src/arpa/inet/inet_aton.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(in_addr_t, inet_addr, (const char *cp)) {
+  in_addr addr;
+  return inet_aton(cp, &addr) ? addr.s_addr : INADDR_NONE;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/arpa/inet/inet_addr.h

@@ -0,0 +1,21 @@
+//===-- Implementation header of inet_addr ----------------------*- 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_ARPA_INET_INET_ADDR_H
+#define LLVM_LIBC_SRC_ARPA_INET_INET_ADDR_H
+
+#include "include/llvm-libc-types/in_addr_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+in_addr_t inet_addr(const char *cp);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_ARPA_INET_INET_ADDR_H

libc/test/src/arpa/inet/CMakeLists.txt

@@ -22,6 +22,17 @@ add_libc_unittest(
     libc.src.arpa.inet.ntohs
 )
 
+add_libc_unittest(
+  inet_addr
+  SUITE
+    libc_arpa_inet_unittests
+  SRCS
+    inet_addr_test.cpp
+  DEPENDS
+    libc.src.arpa.inet.htonl
+    libc.src.arpa.inet.inet_addr
+)
+
 add_libc_unittest(
   inet_aton
   SUITE

libc/test/src/arpa/inet/inet_addr_test.cpp

@@ -0,0 +1,25 @@
+//===-- Unittests for inet_addr -------------------------------------------===//
+//
+// 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/arpa/inet/htonl.h"
+#include "src/arpa/inet/inet_addr.h"
+#include "test/UnitTest/Test.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+TEST(LlvmLibcInetAddr, ValidTest) {
+  ASSERT_EQ(htonl(0x7f010204), inet_addr("127.1.2.4"));
+  ASSERT_EQ(htonl(0x7f010004), inet_addr("127.1.4"));
+}
+
+TEST(LlvmLibcInetAddr, InvalidTest) {
+  ASSERT_EQ(htonl(0xffffffff), inet_addr(""));
+  ASSERT_EQ(htonl(0xffffffff), inet_addr("x"));
+}
+
+} // namespace LIBC_NAMESPACE_DECL