[libc-commits] [libc] Implement inet_pton (PR #224644)
via libc-commits
libc-commits at lists.llvm.org
Fri Sep 18 06:56:50 PDT 2026
llvmorg-github-actions[bot] wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: yahia (afnrow)
<details>
<summary>Changes</summary>
Implement the `inet_pton` function for `IPV4` and its unit tests.
Assisted-by: gemini
---
Full diff: https://github.com/llvm/llvm-project/pull/224644.diff
7 Files Affected:
- (modified) libc/config/linux/x86_64/entrypoints.txt (+1)
- (modified) libc/include/arpa/inet.yaml (+8)
- (modified) libc/src/arpa/inet/CMakeLists.txt (+20)
- (added) libc/src/arpa/inet/inet_pton.cpp (+73)
- (added) libc/src/arpa/inet/inet_pton.h (+25)
- (modified) libc/test/src/arpa/inet/CMakeLists.txt (+15)
- (added) libc/test/src/arpa/inet/inet_pton_test.cpp (+93)
``````````diff
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 8e748287a2469..6554cfe0037e6 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -6,6 +6,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.arpa.inet.inet_aton
libc.src.arpa.inet.inet_ntoa
libc.src.arpa.inet.inet_ntop
+ libc.src.arpa.inet.inet_pton
libc.src.arpa.inet.ntohl
libc.src.arpa.inet.ntohs
diff --git a/libc/include/arpa/inet.yaml b/libc/include/arpa/inet.yaml
index 6629974844186..b533382fedf4b 100644
--- a/libc/include/arpa/inet.yaml
+++ b/libc/include/arpa/inet.yaml
@@ -53,3 +53,11 @@ functions:
- type: const void *__restrict
- type: char *__restrict
- type: socklen_t
+ - name: inet_pton
+ standards:
+ - posix
+ return_type: int
+ arguments:
+ - type: int
+ - type: const char *__restrict
+ - type: void *__restrict
diff --git a/libc/src/arpa/inet/CMakeLists.txt b/libc/src/arpa/inet/CMakeLists.txt
index e0b12ed33e947..65ab3fd1bd562 100644
--- a/libc/src/arpa/inet/CMakeLists.txt
+++ b/libc/src/arpa/inet/CMakeLists.txt
@@ -90,6 +90,26 @@ add_entrypoint_object(
libc.src.__support.net.address
)
+add_entrypoint_object(
+ inet_pton
+ SRCS
+ inet_pton.cpp
+ HDRS
+ inet_pton.h
+ DEPENDS
+ libc.hdr.errno_macros
+ libc.hdr.stdint_proxy
+ libc.hdr.types.struct_in6_addr
+ libc.hdr.types.struct_in_addr
+ libc.src.__support.CPP.string_view
+ libc.src.__support.common
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.config
+ libc.src.__support.macros.null_check
+ libc.src.__support.str_to_integer
+ libc.hdr.sys_socket_macros
+)
+
add_entrypoint_object(
ntohl
SRCS
diff --git a/libc/src/arpa/inet/inet_pton.cpp b/libc/src/arpa/inet/inet_pton.cpp
new file mode 100644
index 0000000000000..632386c56d252
--- /dev/null
+++ b/libc/src/arpa/inet/inet_pton.cpp
@@ -0,0 +1,73 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation for inet_pton
+///
+//===----------------------------------------------------------------------===//
+
+#include "inet_pton.h"
+
+#include "hdr/errno_macros.h"
+#include "hdr/stdint_proxy.h"
+#include "hdr/types/struct_in6_addr.h"
+#include "hdr/types/struct_in_addr.h"
+#include "src/__support/CPP/string_view.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/null_check.h"
+#include "src/__support/str_to_integer.h"
+#include "hdr/sys_socket_macros.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, inet_pton,
+ (int af, const char *__restrict src, void *__restrict dst)) {
+ LIBC_CRASH_ON_NULLPTR(src);
+ LIBC_CRASH_ON_NULLPTR(dst);
+ if (af == AF_INET6) {
+ return 0;
+ }
+ else if (af != AF_INET) {
+ libc_errno = EAFNOSUPPORT;
+ return -1;
+ }
+ uint8_t bytes[4];
+ size_t start = 0;
+ cpp::string_view str(src);
+ size_t i{0};
+ for (; i < 4; ++i) {
+ size_t end = str.find_first_of('.', start);
+ if (i < 3 && start == cpp::string_view::npos)
+ return 0; // Missing dot
+ if (i == 3 && end != cpp::string_view::npos)
+ return 0; // Extra dot
+ cpp::string_view part =
+ (i == 3) ? str.substr(start) : str.substr(start, end - start);
+ if (part.empty())
+ return 0; // empty part e.g. 192..1.1
+ if (part.size() > 1 && part[0] == '0')
+ return 0;
+ // Ensure all characters are valid ascii
+ for (char c : part) {
+ if (c < '0' || c > '9')
+ return 0;
+ }
+ auto result = internal::strtointeger<uint32_t>(part.data(), 10);
+ if (result.has_error() || result.value > 255 || result.value < 0)
+ return 0;
+ bytes[i] = static_cast<uint8_t>(result.value);
+ start = end + 1;
+ }
+ auto *addr = reinterpret_cast<struct in_addr *>(dst);
+ __builtin_memcpy(&addr->s_addr, bytes, 4);
+ return 1;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/arpa/inet/inet_pton.h b/libc/src/arpa/inet/inet_pton.h
new file mode 100644
index 0000000000000..ec682a4c9cf2f
--- /dev/null
+++ b/libc/src/arpa/inet/inet_pton.h
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of POSIX inet_pton function
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_ARPA_INET_PTON_H
+#define LLVM_LIBC_SRC_ARPA_INET_PTON_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int inet_pton(int af, const char *__restrict src, void *__restrict dst);
+
+}
+
+#endif
diff --git a/libc/test/src/arpa/inet/CMakeLists.txt b/libc/test/src/arpa/inet/CMakeLists.txt
index c8e1ca5bf7f35..5d9c98ba4cde3 100644
--- a/libc/test/src/arpa/inet/CMakeLists.txt
+++ b/libc/test/src/arpa/inet/CMakeLists.txt
@@ -72,6 +72,21 @@ add_libc_test(
libc.test.UnitTest.ErrnoCheckingTest
)
+add_libc_test(
+ inet_pton
+ SUITE
+ libc_arpa_inet_unittests
+ SRCS
+ inet_pton_test.cpp
+ DEPENDS
+ libc.hdr.errno_macros
+ libc.hdr.types.struct_in_addr
+ libc.src.arpa.inet.inet_pton
+ libc.src.__support.libc_errno
+ libc.hdr.sys_socket_macros
+ libc.test.UnitTest.ErrnoCheckingTest
+)
+
add_libc_test(
ntohl
SUITE
diff --git a/libc/test/src/arpa/inet/inet_pton_test.cpp b/libc/test/src/arpa/inet/inet_pton_test.cpp
new file mode 100644
index 0000000000000..ff49c374553b5
--- /dev/null
+++ b/libc/test/src/arpa/inet/inet_pton_test.cpp
@@ -0,0 +1,93 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Unittests for inet_pton.
+///
+//===----------------------------------------------------------------------===//
+
+#include "hdr/errno_macros.h"
+#include "hdr/sys_socket_macros.h"
+#include "hdr/types/struct_in_addr.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/endian_internal.h"
+#include "src/arpa/inet/inet_pton.h"
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcInetPtonTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+static uint32_t ipv4_bits(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
+ return LIBC_NAMESPACE::Endian::to_big_endian(
+ static_cast<uint32_t>(a) << 24 | static_cast<uint32_t>(b) << 16 |
+ static_cast<uint32_t>(c) << 8 | static_cast<uint32_t>(d));
+}
+
+TEST_F(LlvmLibcInetPtonTest, ValidIPv4Addresses) {
+ struct in_addr addr;
+
+ EXPECT_EQ(1, LIBC_NAMESPACE::inet_pton(AF_INET, "127.0.0.1", &addr));
+ EXPECT_EQ(addr.s_addr, ipv4_bits(127, 0, 0, 1));
+ ASSERT_ERRNO_SUCCESS();
+
+ EXPECT_EQ(1, LIBC_NAMESPACE::inet_pton(AF_INET, "192.168.1.254", &addr));
+ EXPECT_EQ(addr.s_addr, ipv4_bits(192, 168, 1, 254));
+ ASSERT_ERRNO_SUCCESS();
+
+ EXPECT_EQ(1, LIBC_NAMESPACE::inet_pton(AF_INET, "0.0.0.0", &addr));
+ EXPECT_EQ(addr.s_addr, ipv4_bits(0, 0, 0, 0));
+ ASSERT_ERRNO_SUCCESS();
+
+ EXPECT_EQ(1, LIBC_NAMESPACE::inet_pton(AF_INET, "255.255.255.255", &addr));
+ EXPECT_EQ(addr.s_addr, ipv4_bits(255, 255, 255, 255));
+ ASSERT_ERRNO_SUCCESS();
+}
+
+TEST_F(LlvmLibcInetPtonTest, InvalidOctetValues) {
+ struct in_addr addr;
+
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "256.0.0.1", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "192.168.1.300", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "192.168.-1.1", &addr));
+ ASSERT_ERRNO_SUCCESS();
+}
+
+TEST_F(LlvmLibcInetPtonTest, InvalidFormats) {
+ struct in_addr addr;
+
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "127.0.0", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "10.0.0.0.1", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, ".1.2.3.4", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "1.2.3.4.", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "192..168.1.1", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "192.168.1.1a", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "abc.def.ghi.jkl", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "127.0.0.1 ", &addr));
+ ASSERT_ERRNO_SUCCESS();
+}
+
+TEST_F(LlvmLibcInetPtonTest, StrictPosixLeadingZeros) {
+ struct in_addr addr;
+
+ // inet_pton must reject octal-style leading zeros
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "192.168.01.1", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "010.0.0.1", &addr));
+ EXPECT_EQ(0, LIBC_NAMESPACE::inet_pton(AF_INET, "00.0.0.0", &addr));
+ ASSERT_ERRNO_SUCCESS();
+}
+
+TEST_F(LlvmLibcInetPtonTest, InvalidAddressFamily) {
+ struct in_addr addr;
+
+ EXPECT_EQ(-1, LIBC_NAMESPACE::inet_pton(AF_INET + AF_INET6 + 1, "127.0.0.1",
+ &addr));
+ ASSERT_ERRNO_EQ(EAFNOSUPPORT);
+
+ EXPECT_EQ(-1, LIBC_NAMESPACE::inet_pton(12345, "127.0.0.1", &addr));
+ ASSERT_ERRNO_EQ(EAFNOSUPPORT);
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/224644
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