[libc-commits] [libc] Implement process_vm_readv and process_vm_writev functions (PR #237705)

Mallarapu Ujwal via libc-commits libc-commits at lists.llvm.org
Sun Nov 1 02:45:40 PST 2026


https://github.com/ujwal-224 updated https://github.com/llvm/llvm-project/pull/237705

>From db97f00c631e83599dfd3d2df4c3fc139a0340c1 Mon Sep 17 00:00:00 2001
From: ujwal-224 <mallarapuujwal9 at gmail.com>
Date: Sun, 1 Nov 2026 16:10:21 +0530
Subject: [PATCH] [libc] Implement process_vm_readv and process_vm_writev
 (#236162)

---
 libc/config/linux/aarch64/entrypoints.txt     |  2 +
 libc/config/linux/riscv/entrypoints.txt       |  2 +
 libc/config/linux/x86_64/entrypoints.txt      |  2 +
 libc/include/CMakeLists.txt                   |  1 +
 libc/include/sys/uio.yaml                     | 24 ++++++++++
 .../linux/syscall_wrappers/CMakeLists.txt     | 28 +++++++++++
 .../linux/syscall_wrappers/process_vm_readv.h | 41 ++++++++++++++++
 .../syscall_wrappers/process_vm_writev.h      | 41 ++++++++++++++++
 libc/src/sys/uio/CMakeLists.txt               | 13 +++++
 libc/src/sys/uio/linux/CMakeLists.txt         | 33 +++++++++++++
 libc/src/sys/uio/linux/process_vm_readv.cpp   | 39 +++++++++++++++
 libc/src/sys/uio/linux/process_vm_writev.cpp  | 39 +++++++++++++++
 libc/src/sys/uio/process_vm_readv.h           | 25 ++++++++++
 libc/src/sys/uio/process_vm_writev.h          | 25 ++++++++++
 libc/test/src/sys/uio/CMakeLists.txt          | 29 +++++++++++
 .../src/sys/uio/process_vm_readv_test.cpp     | 48 +++++++++++++++++++
 .../src/sys/uio/process_vm_writev_test.cpp    | 47 ++++++++++++++++++
 17 files changed, 439 insertions(+)
 create mode 100644 libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_readv.h
 create mode 100644 libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_writev.h
 create mode 100644 libc/src/sys/uio/linux/process_vm_readv.cpp
 create mode 100644 libc/src/sys/uio/linux/process_vm_writev.cpp
 create mode 100644 libc/src/sys/uio/process_vm_readv.h
 create mode 100644 libc/src/sys/uio/process_vm_writev.h
 create mode 100644 libc/test/src/sys/uio/process_vm_readv_test.cpp
 create mode 100644 libc/test/src/sys/uio/process_vm_writev_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index b1163f266f1b62..60b8686ba654e5 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -546,6 +546,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
     libc.src.sys.uio.readv
+    libc.src.sys.uio.process_vm_readv
+    libc.src.sys.uio.process_vm_writev
 
     # sys/time.h entrypoints
     libc.src.sys.time.setitimer
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 839d4f539b916d..6ddc219ce8caaa 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -603,6 +603,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
     libc.src.sys.uio.readv
+    libc.src.sys.uio.process_vm_readv
+    libc.src.sys.uio.process_vm_writev
 
     # sys/time.h entrypoints
     libc.src.sys.time.setitimer
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 483a4d371c5a95..4bbe7ea0257663 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -625,6 +625,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
     libc.src.sys.uio.readv
+    libc.src.sys.uio.process_vm_readv
+    libc.src.sys.uio.process_vm_writev
 
     # sys/time.h entrypoints
     libc.src.sys.time.setitimer
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index 0130ba1d72e0e1..4089cdd7bedf7e 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -1089,6 +1089,7 @@ add_header_macro(
     .llvm_libc_common_h
     .llvm-libc-types.struct_iovec
     .llvm-libc-types.ssize_t
+    .llvm-libc-types.pid_t
 )
 
 add_header_macro(
diff --git a/libc/include/sys/uio.yaml b/libc/include/sys/uio.yaml
index 929911e6693865..7da273dfbfc335 100644
--- a/libc/include/sys/uio.yaml
+++ b/libc/include/sys/uio.yaml
@@ -1,9 +1,11 @@
 header: sys/uio.h
 standards:
   - posix
+  - linux
 types:
   - type_name: struct_iovec
   - type_name: ssize_t
+  - type_name: pid_t
 functions:
   - name: writev
     standards:
@@ -21,3 +23,25 @@ functions:
       - type: int
       - type: const struct iovec *
       - type: int
+  - name: process_vm_readv
+    standards:
+      - linux
+    return_type: ssize_t
+    arguments:
+      - type: pid_t
+      - type: const struct iovec *
+      - type: unsigned long
+      - type: const struct iovec *
+      - type: unsigned long
+      - type: unsigned long
+  - name: process_vm_writev
+    standards:
+      - linux
+    return_type: ssize_t
+    arguments:
+      - type: pid_t
+      - type: const struct iovec *
+      - type: unsigned long
+      - type: const struct iovec *
+      - type: unsigned long
+      - type: unsigned long
\ No newline at end of file
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
index 8cff89c818baaa..f3b9c4aa427abd 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
@@ -434,7 +434,35 @@ add_header_library(
     libc.hdr.types.ssize_t
     libc.include.sys_syscall
 )
+add_header_library(
+  process_vm_readv
+  HDRS
+    process_vm_readv.h
+  DEPENDS
+    libc.hdr.types.pid_t
+    libc.hdr.types.ssize_t
+    libc.hdr.types.struct_iovec
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.macros.config
+)
 
+add_header_library(
+  process_vm_writev
+  HDRS
+    process_vm_writev.h
+  DEPENDS
+    libc.hdr.types.pid_t
+    libc.hdr.types.ssize_t
+    libc.hdr.types.struct_iovec
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.macros.config
+)
 add_header_library(
   recvfrom
   HDRS
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_readv.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_readv.h
new file mode 100644
index 00000000000000..5602191cb8f022
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_readv.h
@@ -0,0 +1,41 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+/// Syscall wrapper for process_vm_readv.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_READV_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_READV_H
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/OSUtil/linux/syscall.h" // syscall_checked
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+
+#include <sys/syscall.h> // For syscall numbers
+
+namespace LIBC_NAMESPACE_DECL {
+namespace linux_syscalls {
+
+LIBC_INLINE ErrorOr<ssize_t>
+process_vm_readv(pid_t pid, const struct iovec *local_iov,
+                 unsigned long liovcnt, const struct iovec *remote_iov,
+                 unsigned long riovcnt, unsigned long flags) {
+  return syscall_checked<ssize_t>(SYS_process_vm_readv, pid, local_iov, liovcnt,
+                                  remote_iov, riovcnt, flags);
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_READV_H
\ No newline at end of file
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_writev.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_writev.h
new file mode 100644
index 00000000000000..d8d3d7d22d8944
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/process_vm_writev.h
@@ -0,0 +1,41 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+/// Syscall wrapper for process_vm_writev.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_WRITEV_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_WRITEV_H
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/OSUtil/linux/syscall.h" // syscall_checked
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+
+#include <sys/syscall.h> // For syscall numbers
+
+namespace LIBC_NAMESPACE_DECL {
+namespace linux_syscalls {
+
+LIBC_INLINE ErrorOr<ssize_t>
+process_vm_writev(pid_t pid, const struct iovec *local_iov,
+                  unsigned long liovcnt, const struct iovec *remote_iov,
+                  unsigned long riovcnt, unsigned long flags) {
+  return syscall_checked<ssize_t>(SYS_process_vm_writev, pid, local_iov,
+                                  liovcnt, remote_iov, riovcnt, flags);
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_PROCESS_VM_WRITEV_H
\ No newline at end of file
diff --git a/libc/src/sys/uio/CMakeLists.txt b/libc/src/sys/uio/CMakeLists.txt
index c6a64297904103..c499350ba9ecfc 100644
--- a/libc/src/sys/uio/CMakeLists.txt
+++ b/libc/src/sys/uio/CMakeLists.txt
@@ -15,3 +15,16 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.readv
 )
+add_entrypoint_object(
+  process_vm_readv
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.process_vm_readv
+)
+
+add_entrypoint_object(
+  process_vm_writev
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.process_vm_writev
+)
\ No newline at end of file
diff --git a/libc/src/sys/uio/linux/CMakeLists.txt b/libc/src/sys/uio/linux/CMakeLists.txt
index db4fe68e4ca9c5..f1ae8f1ca0c8d5 100644
--- a/libc/src/sys/uio/linux/CMakeLists.txt
+++ b/libc/src/sys/uio/linux/CMakeLists.txt
@@ -27,3 +27,36 @@ add_entrypoint_object(
     libc.src.__support.common
     libc.src.errno.errno
 )
+add_entrypoint_object(
+  process_vm_readv
+  SRCS
+    process_vm_readv.cpp
+  HDRS
+    ../process_vm_readv.h
+  DEPENDS
+    libc.hdr.types.pid_t
+    libc.hdr.types.ssize_t
+    libc.hdr.types.struct_iovec
+    libc.src.__support.OSUtil.linux.syscall_wrappers.process_vm_readv
+    libc.src.__support.common
+    libc.src.__support.libc_errno
+    libc.src.__support.macros.config
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  process_vm_writev
+  SRCS
+    process_vm_writev.cpp
+  HDRS
+    ../process_vm_writev.h
+  DEPENDS
+    libc.hdr.types.pid_t
+    libc.hdr.types.ssize_t
+    libc.hdr.types.struct_iovec
+    libc.src.__support.OSUtil.linux.syscall_wrappers.process_vm_writev
+    libc.src.__support.common
+    libc.src.__support.libc_errno
+    libc.src.__support.macros.config
+    libc.src.errno.errno
+)
\ No newline at end of file
diff --git a/libc/src/sys/uio/linux/process_vm_readv.cpp b/libc/src/sys/uio/linux/process_vm_readv.cpp
new file mode 100644
index 00000000000000..b237c6abe57159
--- /dev/null
+++ b/libc/src/sys/uio/linux/process_vm_readv.cpp
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+/// Linux implementation of process_vm_readv.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/sys/uio/process_vm_readv.h"
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/process_vm_readv.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(ssize_t, process_vm_readv,
+                   (pid_t pid, const struct iovec *local_iov,
+                    unsigned long liovcnt, const struct iovec *remote_iov,
+                    unsigned long riovcnt, unsigned long flags)) {
+  ErrorOr<ssize_t> ret = linux_syscalls::process_vm_readv(
+      pid, local_iov, liovcnt, remote_iov, riovcnt, flags);
+  if (!ret) {
+    libc_errno = ret.error();
+    return -1;
+  }
+  return ret.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL
\ No newline at end of file
diff --git a/libc/src/sys/uio/linux/process_vm_writev.cpp b/libc/src/sys/uio/linux/process_vm_writev.cpp
new file mode 100644
index 00000000000000..bc772e39764074
--- /dev/null
+++ b/libc/src/sys/uio/linux/process_vm_writev.cpp
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+/// Linux implementation of process_vm_writev.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/sys/uio/process_vm_writev.h"
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/process_vm_writev.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(ssize_t, process_vm_writev,
+                   (pid_t pid, const struct iovec *local_iov,
+                    unsigned long liovcnt, const struct iovec *remote_iov,
+                    unsigned long riovcnt, unsigned long flags)) {
+  ErrorOr<ssize_t> ret = linux_syscalls::process_vm_writev(
+      pid, local_iov, liovcnt, remote_iov, riovcnt, flags);
+  if (!ret) {
+    libc_errno = ret.error();
+    return -1;
+  }
+  return ret.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL
\ No newline at end of file
diff --git a/libc/src/sys/uio/process_vm_readv.h b/libc/src/sys/uio/process_vm_readv.h
new file mode 100644
index 00000000000000..9d80aede3f0c90
--- /dev/null
+++ b/libc/src/sys/uio/process_vm_readv.h
@@ -0,0 +1,25 @@
+//===-- Implementation header for process_vm_readv ------------------------===//
+//
+// 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_SYS_UIO_PROCESS_VM_READV_H
+#define LLVM_LIBC_SRC_SYS_UIO_PROCESS_VM_READV_H
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+ssize_t process_vm_readv(pid_t pid, const struct iovec *local_iov,
+                         unsigned long liovcnt, const struct iovec *remote_iov,
+                         unsigned long riovcnt, unsigned long flags);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SYS_UIO_PROCESS_VM_READV_H
\ No newline at end of file
diff --git a/libc/src/sys/uio/process_vm_writev.h b/libc/src/sys/uio/process_vm_writev.h
new file mode 100644
index 00000000000000..a2d18ec4494a7b
--- /dev/null
+++ b/libc/src/sys/uio/process_vm_writev.h
@@ -0,0 +1,25 @@
+//===-- Implementation header for process_vm_writev -----------------------===//
+//
+// 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_SYS_UIO_PROCESS_VM_WRITEV_H
+#define LLVM_LIBC_SRC_SYS_UIO_PROCESS_VM_WRITEV_H
+
+#include "hdr/types/pid_t.h"
+#include "hdr/types/ssize_t.h"
+#include "hdr/types/struct_iovec.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+ssize_t process_vm_writev(pid_t pid, const struct iovec *local_iov,
+                          unsigned long liovcnt, const struct iovec *remote_iov,
+                          unsigned long riovcnt, unsigned long flags);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SYS_UIO_PROCESS_VM_WRITEV_H
\ No newline at end of file
diff --git a/libc/test/src/sys/uio/CMakeLists.txt b/libc/test/src/sys/uio/CMakeLists.txt
index 0350cf79d7998b..b9c9984040a308 100644
--- a/libc/test/src/sys/uio/CMakeLists.txt
+++ b/libc/test/src/sys/uio/CMakeLists.txt
@@ -33,3 +33,32 @@ add_libc_test(
     libc.src.unistd.write
     libc.test.UnitTest.ErrnoSetterMatcher
 )
+add_libc_test(
+  process_vm_readv_test
+  SUITE
+    libc-sys-uio-tests
+  SRCS
+    process_vm_readv_test.cpp
+  DEPENDS
+    libc.hdr.types.struct_iovec
+    libc.src.__support.common
+    libc.src.errno.errno
+    libc.src.sys.uio.process_vm_readv
+    libc.src.unistd.getpid
+    libc.test.UnitTest.ErrnoSetterMatcher
+)
+
+add_libc_test(
+  process_vm_writev_test
+  SUITE
+    libc-sys-uio-tests
+  SRCS
+    process_vm_writev_test.cpp
+  DEPENDS
+    libc.hdr.types.struct_iovec
+    libc.src.__support.common
+    libc.src.errno.errno
+    libc.src.sys.uio.process_vm_writev
+    libc.src.unistd.getpid
+    libc.test.UnitTest.ErrnoSetterMatcher
+)
\ No newline at end of file
diff --git a/libc/test/src/sys/uio/process_vm_readv_test.cpp b/libc/test/src/sys/uio/process_vm_readv_test.cpp
new file mode 100644
index 00000000000000..dde2fa1bbbb438
--- /dev/null
+++ b/libc/test/src/sys/uio/process_vm_readv_test.cpp
@@ -0,0 +1,48 @@
+//===-- Unittests for process_vm_readv ------------------------------------===//
+//
+// 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 "hdr/types/struct_iovec.h"
+#include "src/sys/uio/process_vm_readv.h"
+#include "src/unistd/getpid.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+
+TEST(LlvmLibcSysUioProcessVmReadvTest, SmokeTest) {
+  pid_t pid = LIBC_NAMESPACE::getpid();
+  char src[] = "Hello, World!\n";
+
+  struct iovec remote_iov[1];
+  remote_iov[0].iov_base = src;
+  remote_iov[0].iov_len = sizeof(src);
+
+  char buf0[7];
+  char buf1[8];
+  struct iovec local_iov[2];
+  local_iov[0].iov_base = buf0;
+  local_iov[0].iov_len = 7;
+  local_iov[1].iov_base = buf1;
+  local_iov[1].iov_len = sizeof(src) - 7;
+
+  ASSERT_THAT(
+      LIBC_NAMESPACE::process_vm_readv(pid, local_iov, 2, remote_iov, 1, 0),
+      returns(EQ(ssize_t(sizeof(src)))).with_errno(EQ(0)));
+
+  EXPECT_EQ(buf0[0], 'H');
+  EXPECT_EQ(buf0[6], ' ');
+  EXPECT_EQ(buf1[0], 'W');
+}
+
+TEST(LlvmLibcSysUioProcessVmReadvTest, InvalidFlags) {
+  pid_t pid = LIBC_NAMESPACE::getpid();
+  char buf[8];
+  struct iovec iov = {buf, sizeof(buf)};
+  ASSERT_THAT(LIBC_NAMESPACE::process_vm_readv(pid, &iov, 1, &iov, 1, 1),
+              returns(EQ(ssize_t(-1))).with_errno(EQ(EINVAL)));
+}
\ No newline at end of file
diff --git a/libc/test/src/sys/uio/process_vm_writev_test.cpp b/libc/test/src/sys/uio/process_vm_writev_test.cpp
new file mode 100644
index 00000000000000..ce0f5275387ce2
--- /dev/null
+++ b/libc/test/src/sys/uio/process_vm_writev_test.cpp
@@ -0,0 +1,47 @@
+//===-- Unittests for process_vm_writev -----------------------------------===//
+//
+// 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 "hdr/types/struct_iovec.h"
+#include "src/sys/uio/process_vm_writev.h"
+#include "src/unistd/getpid.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+
+TEST(LlvmLibcSysUioProcessVmWritevTest, SmokeTest) {
+  pid_t pid = LIBC_NAMESPACE::getpid();
+  char dest[15] = {};
+
+  struct iovec remote_iov[1];
+  remote_iov[0].iov_base = dest;
+  remote_iov[0].iov_len = sizeof(dest);
+
+  char part0[] = "Hello, ";
+  char part1[] = "World!\n";
+  struct iovec local_iov[2];
+  local_iov[0].iov_base = part0;
+  local_iov[0].iov_len = 7;
+  local_iov[1].iov_base = part1;
+  local_iov[1].iov_len = 8; // includes '\n' and '\0'
+
+  ASSERT_THAT(
+      LIBC_NAMESPACE::process_vm_writev(pid, local_iov, 2, remote_iov, 1, 0),
+      returns(EQ(ssize_t(15))).with_errno(EQ(0)));
+
+  EXPECT_EQ(dest[0], 'H');
+  EXPECT_EQ(dest[7], 'W');
+}
+
+TEST(LlvmLibcSysUioProcessVmWritevTest, InvalidFlags) {
+  pid_t pid = LIBC_NAMESPACE::getpid();
+  char buf[8];
+  struct iovec iov = {buf, sizeof(buf)};
+  ASSERT_THAT(LIBC_NAMESPACE::process_vm_writev(pid, &iov, 1, &iov, 1, 1),
+              returns(EQ(ssize_t(-1))).with_errno(EQ(EINVAL)));
+}
\ No newline at end of file



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