[PATCH v2 09/11] tools/nolibc: add uio.h with readv and writev

Benjamin Berg
2025-09-19T15:36:13Z

From: Benjamin Berg <benjamin.berg@intel.com>

This is generally useful and struct iovec is also needed for other
purposes such as ptrace.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
---
tools/include/nolibc/Makefile | 1 +
tools/include/nolibc/nolibc.h | 1 +
tools/include/nolibc/sys/uio.h | 49 ++++++++++++++++++++
tools/testing/selftests/nolibc/nolibc-test.c | 9 ++++
4 files changed, 60 insertions(+)
create mode 100644 tools/include/nolibc/sys/uio.h

diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 143c2d2c2ba6..9bbbba32dac6 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -62,6 +62,7 @@ all_files := \
sys/time.h \
sys/timerfd.h \
sys/types.h \
+ sys/uio.h \
sys/utsname.h \
sys/wait.h \
time.h \
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index c199ade200c2..b4bc1c9b883d 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -109,6 +109,7 @@
#include "sys/sysmacros.h"
#include "sys/time.h"
#include "sys/timerfd.h"
+#include "sys/uio.h"
#include "sys/utsname.h"
#include "sys/wait.h"
#include "ctype.h"
diff --git a/tools/include/nolibc/sys/uio.h b/tools/include/nolibc/sys/uio.h
new file mode 100644
index 000000000000..7ad42b927d2f
--- /dev/null
+++ b/tools/include/nolibc/sys/uio.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * uio for NOLIBC
+ * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
+ * Copyright (C) 2025 Intel Corporation
+ */
+
+/* make sure to include all global symbols */
+#include "../nolibc.h"
+
+#ifndef _NOLIBC_SYS_UIO_H
+#define _NOLIBC_SYS_UIO_H
+
+#include "../sys.h"
+#include <linux/uio.h>
+
+
+/*
+ * ssize_t readv(int fd, const struct iovec *iovec, int count);
+ */
+static __attribute__((unused))
+ssize_t sys_readv(int fd, const struct iovec *iovec, int count)
+{
+ return my_syscall3(__NR_readv, fd, iovec, count);
+}
+
+static __attribute__((unused))
+ssize_t readv(int fd, const struct iovec *iovec, int count)
+{
+ return __sysret(sys_readv(fd, iovec, count));
+}
+
+/*
+ * ssize_t writev(int fd, const struct iovec *iovec, int count);
+ */
+static __attribute__((unused))
+ssize_t sys_writev(int fd, const struct iovec *iovec, int count)
+{
+ return my_syscall3(__NR_writev, fd, iovec, count);
+}
+
+static __attribute__((unused))
+ssize_t writev(int fd, const struct iovec *iovec, int count)
+{
+ return __sysret(sys_writev(fd, iovec, count));
+}
+
+
+#endif /* _NOLIBC_SYS_UIO_H */
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index a297ee0d6d07..1907128bc3f6 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -25,6 +25,7 @@
#include <sys/sysmacros.h>
#include <sys/time.h>
#include <sys/timerfd.h>
+#include <sys/uio.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <dirent.h>
@@ -1283,6 +1284,10 @@ int run_syscall(int min, int max)
int proc;
int test;
int tmp;
+ struct iovec iov_one = {
+ .iov_base = &tmp,
+ .iov_len = 1,
+ };
int ret = 0;
void *p1, *p2;
int has_gettid = 1;
@@ -1395,6 +1400,10 @@ int run_syscall(int min, int max)
CASE_TEST(waitpid_child); EXPECT_SYSER(1, waitpid(getpid(), &tmp, WNOHANG), -1, ECHILD); break;
CASE_TEST(write_badf); EXPECT_SYSER(1, write(-1, &tmp, 1), -1, EBADF); break;
CASE_TEST(write_zero); EXPECT_SYSZR(1, write(1, &tmp, 0)); break;
+ CASE_TEST(readv_badf); EXPECT_SYSER(1, readv(-1, &iov_one, 1), -1, EBADF); break;
+ CASE_TEST(readv_zero); EXPECT_SYSZR(1, readv(1, NULL, 0)); break;
+ CASE_TEST(writev_badf); EXPECT_SYSER(1, writev(-1, &iov_one, 1), -1, EBADF); break;
+ CASE_TEST(writev_zero); EXPECT_SYSZR(1, writev(1, NULL, 0)); break;
CASE_TEST(syscall_noargs); EXPECT_SYSEQ(1, syscall(__NR_getpid), getpid()); break;
CASE_TEST(syscall_args); EXPECT_SYSER(1, syscall(__NR_statx, 0, NULL, 0, 0, NULL), -1, EFAULT); break;
CASE_TEST(namespace); EXPECT_SYSZR(euid0 && proc, test_namespace()); break;
--
2.51.0