[libc-commits] [libc] 5ad347d - [libc][POSIX][unistd] Implement gethostname (#128142)
via libc-commits
libc-commits at lists.llvm.org
Tue Sep 23 06:54:39 PDT 2025
Author: Zaky Hermawan
Date: 2025-09-23T09:54:35-04:00
New Revision: 5ad347d1a1c1bdc716dafd07a395861529c0e595
URL: https://github.com/llvm/llvm-project/commit/5ad347d1a1c1bdc716dafd07a395861529c0e595
DIFF: https://github.com/llvm/llvm-project/commit/5ad347d1a1c1bdc716dafd07a395861529c0e595.diff
LOG: [libc][POSIX][unistd] Implement gethostname (#128142)
The implementation is based on the specifications from:
https://man7.org/linux/man-pages/man2/gethostname.2.html
Closes https://github.com/llvm/llvm-project/issues/126602
---------
Signed-off-by: ZakyHermawan <zaky.hermawan9615 at gmail.com>
Added:
libc/src/unistd/gethostname.h
libc/src/unistd/linux/gethostname.cpp
libc/test/src/unistd/gethostname_test.cpp
Modified:
libc/config/linux/aarch64/entrypoints.txt
libc/config/linux/riscv/entrypoints.txt
libc/config/linux/x86_64/entrypoints.txt
libc/include/unistd.yaml
libc/src/unistd/CMakeLists.txt
libc/src/unistd/linux/CMakeLists.txt
libc/test/src/unistd/CMakeLists.txt
Removed:
################################################################################
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index e38fc857d4e16..61b585d2d24ca 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -332,6 +332,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.getcwd
libc.src.unistd.getentropy
libc.src.unistd.geteuid
+ libc.src.unistd.gethostname
libc.src.unistd.getpid
libc.src.unistd.getppid
libc.src.unistd.getsid
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 89e3653186d13..2b8003f9f2bbf 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -336,6 +336,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.getcwd
libc.src.unistd.getentropy
libc.src.unistd.geteuid
+ libc.src.unistd.gethostname
libc.src.unistd.getpid
libc.src.unistd.getppid
libc.src.unistd.getsid
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 0bb8a683c5b01..19ed6e02e0ea4 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -338,6 +338,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.getcwd
libc.src.unistd.getentropy
libc.src.unistd.geteuid
+ libc.src.unistd.gethostname
libc.src.unistd.getpid
libc.src.unistd.getppid
libc.src.unistd.getsid
diff --git a/libc/include/unistd.yaml b/libc/include/unistd.yaml
index 051e92b006741..3ba3ec71c25ce 100644
--- a/libc/include/unistd.yaml
+++ b/libc/include/unistd.yaml
@@ -141,6 +141,13 @@ functions:
return_type: uid_t
arguments:
- type: void
+ - name: gethostname
+ standards:
+ - POSIX
+ return_type: int
+ arguments:
+ - type: char *
+ - type: size_t
- name: getopt
standards:
- POSIX
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index b1a1716aa85c6..c66a3a4d0ed76 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -111,6 +111,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.getcwd
)
+add_entrypoint_object(
+ gethostname
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.gethostname
+)
+
add_entrypoint_object(
getpid
ALIAS
diff --git a/libc/src/unistd/gethostname.h b/libc/src/unistd/gethostname.h
new file mode 100644
index 0000000000000..cf67bdbd5c320
--- /dev/null
+++ b/libc/src/unistd/gethostname.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for gethostname -------------------*- 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_UNISTD_GETHOSTNAME_H
+#define LLVM_LIBC_SRC_UNISTD_GETHOSTNAME_H
+
+#include "hdr/types/size_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int gethostname(char *name, size_t len);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_GETHOSTNAME_H
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index 382a61fea8b66..2d510f32d287d 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -194,6 +194,20 @@ add_entrypoint_object(
libc.src.errno.errno
)
+add_entrypoint_object(
+ gethostname
+ SRCS
+ gethostname.cpp
+ HDRS
+ ../gethostname.h
+ DEPENDS
+ libc.hdr.types.size_t
+ libc.include.sys_syscall
+ libc.include.sys_utsname
+ libc.src.__support.OSUtil.osutil
+ libc.src.errno.errno
+)
+
add_entrypoint_object(
geteuid
SRCS
diff --git a/libc/src/unistd/linux/gethostname.cpp b/libc/src/unistd/linux/gethostname.cpp
new file mode 100644
index 0000000000000..60a12a4d6f8ea
--- /dev/null
+++ b/libc/src/unistd/linux/gethostname.cpp
@@ -0,0 +1,53 @@
+//===-- Linux implementation of gethostname -------------------------------===//
+//
+// 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/unistd/gethostname.h"
+
+#include "hdr/types/size_t.h"
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/string/string_utils.h"
+
+#include <sys/syscall.h> // For syscall numbers.
+#include <sys/utsname.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, gethostname, (char *name, size_t size)) {
+ // Check for invalid pointer
+ if (name == nullptr) {
+ libc_errno = EFAULT;
+ return -1;
+ }
+
+ // Because there is no SYS_gethostname syscall, we use uname to get the
+ // hostname.
+ utsname unameData;
+ int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_uname, &unameData);
+ if (ret < 0) {
+ libc_errno = static_cast<int>(-ret);
+ return -1;
+ }
+
+ // Guarantee that the name will be null terminated.
+ // The amount of bytes copied is min(size + 1, strlen(nodename) + 1)
+ // +1 to account for the null terminator (the last copied byte is a NULL).
+ internal::strlcpy(name, unameData.nodename, size + 1);
+
+ // Checks if the length of the hostname was greater than or equal to size
+ if (internal::string_length(unameData.nodename) >= size) {
+ libc_errno = ENAMETOOLONG;
+ return -1;
+ }
+
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
index 9aec6150af0ec..6630a7ef15e53 100644
--- a/libc/test/src/unistd/CMakeLists.txt
+++ b/libc/test/src/unistd/CMakeLists.txt
@@ -408,6 +408,18 @@ add_libc_unittest(
libc.test.UnitTest.ErrnoSetterMatcher
)
+add_libc_unittest(
+ gethostname_test
+ SUITE
+ libc_unistd_unittests
+ SRCS
+ gethostname_test.cpp
+ DEPENDS
+ libc.src.unistd.gethostname
+ libc.src.errno.errno
+ libc.test.UnitTest.ErrnoCheckingTest
+)
+
add_libc_unittest(
getpid_test
SUITE
diff --git a/libc/test/src/unistd/gethostname_test.cpp b/libc/test/src/unistd/gethostname_test.cpp
new file mode 100644
index 0000000000000..a0e57ff0df333
--- /dev/null
+++ b/libc/test/src/unistd/gethostname_test.cpp
@@ -0,0 +1,31 @@
+//===-- Unittests for gethostname -----------------------------------------===//
+//
+// 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/unistd/gethostname.h"
+
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcGetHostNameTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST(LlvmLibcGetHostNameTest, GetCurrHostName) {
+ char hostbuffer[1024];
+ int ret = LIBC_NAMESPACE::gethostname(hostbuffer, sizeof(hostbuffer));
+ ASSERT_NE(ret, -1);
+ ASSERT_ERRNO_SUCCESS();
+
+ ret = LIBC_NAMESPACE::gethostname(hostbuffer, 0);
+ ASSERT_EQ(ret, -1);
+ ASSERT_ERRNO_EQ(ENAMETOOLONG);
+
+ // test for invalid pointer
+ char *nptr = nullptr;
+ ret = LIBC_NAMESPACE::gethostname(nptr, 1);
+ ASSERT_EQ(ret, -1);
+ ASSERT_ERRNO_EQ(EFAULT);
+}
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