[PATCH v2 nolibc 34/53] tools/nolibc: add support for prctl()

Paul E. McKenney
2023-06-12T20:49:21Z

It will be used to disable core dumps from the child spawned to validate
the stack protector functionality.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
tools/include/nolibc/sys.h | 27 ++++++++++++++++++++
tools/testing/selftests/nolibc/nolibc-test.c | 2 ++
2 files changed, 29 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index d5792a5de70b..c688b410f9e4 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -22,6 +22,7 @@
#include <linux/fcntl.h> /* for O_* and AT_* */
#include <linux/stat.h> /* for statx() */
#include <linux/reboot.h> /* for LINUX_REBOOT_* */
+#include <linux/prctl.h>

#include "arch.h"
#include "errno.h"
@@ -875,6 +876,32 @@ int open(const char *path, int flags, ...)
}

+/*
+ * int prctl(int option, unsigned long arg2, unsigned long arg3,
+ * unsigned long arg4, unsigned long arg5);
+ */
+
+static __attribute__((unused))
+int sys_prctl(int option, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ return my_syscall5(__NR_prctl, option, arg2, arg3, arg4, arg5);
+}
+
+static __attribute__((unused))
+int prctl(int option, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ int ret = sys_prctl(option, arg2, arg3, arg4, arg5);
+
+ if (ret < 0) {
+ SET_ERRNO(-ret);
+ ret = -1;
+ }
+ return ret;
+}
+
+
/*
* int pivot_root(const char *new, const char *old);
*/
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index b50b5a8bcc90..6db788603a34 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -22,6 +22,7 @@
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.h>
+#include <sys/prctl.h>
#include <sys/reboot.h>
#include <sys/stat.h>
#include <sys/syscall.h>
@@ -580,6 +581,7 @@ int run_syscall(int min, int max)
CASE_TEST(poll_null); EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
CASE_TEST(poll_stdout); EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;
CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
+ CASE_TEST(prctl); EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break;
CASE_TEST(read_badf); EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break;
CASE_TEST(sched_yield); EXPECT_SYSZR(1, sched_yield()); break;
CASE_TEST(select_null); EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break;
--
2.40.1