[PATCH v4 1/2] Add an internal wrapper for clone, clone2 and clone3
H.J. Lu
hjl.tools@gmail.com
Tue May 11 01:43:55 GMT 2021
The clone3 system call provides a superset of the functionality of clone
and clone2. It also provides a number of API improve ments, including
the ability to specify the size of the child's stack area which can be
used by kernel to compute the shadow stack size when allocating the
shadow stack. Add:
extern int __clone_internal (struct clone_args *cl_args,
int (*__fn) (void *__arg), void *__arg);
to provide an abstract interface for clone, clone2 and clone3.
1. Add cast_to_pointer to cast an integer to void * pointer.
2. Simplify stack management for thread creation by passing both stack
base and size to create_thread.
3. Consolidate clone vs clone2 differences into a single file.
4. Use only __clone_internal to clone a thread. If clone3 returns -1
with ENOSYS, __clone_internal will fall back to clone or clone2.
5. Add the x86-64 clone3 wrapper.
6. Enable the public clone3 wrapper in the future after it has been
added to all targets.
Tested with build-many-glibcs.py. The x86-64 clone3 wrapper and the
i686 clone fallback are tested under 5.12.2 kernel.
---
include/clone3.h | 14 ++++
include/libc-pointer-arith.h | 3 +
sysdeps/unix/sysv/linux/Makefile | 4 +-
sysdeps/unix/sysv/linux/Versions | 1 +
sysdeps/unix/sysv/linux/clone-internal.c | 80 ++++++++++++++++++++
sysdeps/unix/sysv/linux/clone-offsets.sym | 5 ++
sysdeps/unix/sysv/linux/clone3.c | 34 +++++++++
sysdeps/unix/sysv/linux/clone3.h | 58 ++++++++++++++
sysdeps/unix/sysv/linux/createthread.c | 25 +++---
sysdeps/unix/sysv/linux/spawni.c | 26 +++----
sysdeps/unix/sysv/linux/tst-align-clone.c | 55 +++++++++++---
sysdeps/unix/sysv/linux/tst-clone.c | 23 +++++-
sysdeps/unix/sysv/linux/tst-clone2.c | 61 +++++++++++----
sysdeps/unix/sysv/linux/tst-clone3.c | 60 +++++++++++----
sysdeps/unix/sysv/linux/tst-getpid1.c | 54 ++++++++++---
sysdeps/unix/sysv/linux/x86_64/clone3.S | 92 +++++++++++++++++++++++
16 files changed, 517 insertions(+), 78 deletions(-)
create mode 100644 include/clone3.h
create mode 100644 sysdeps/unix/sysv/linux/clone-internal.c
create mode 100644 sysdeps/unix/sysv/linux/clone-offsets.sym
create mode 100644 sysdeps/unix/sysv/linux/clone3.c
create mode 100644 sysdeps/unix/sysv/linux/clone3.h
create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S
diff --git a/include/clone3.h b/include/clone3.h
new file mode 100644
index 0000000000..124f7ba169
--- /dev/null
+++ b/include/clone3.h
@@ -0,0 +1,14 @@
+#ifndef _CLONE3_H
+#include_next <clone3.h>
+
+extern __typeof (clone3) __clone3;
+
+/* The internal wrapper of clone and clone3. */
+extern __typeof (clone3) __clone_internal;
+
+#ifndef _ISOMAC
+libc_hidden_proto (__clone3)
+libc_hidden_proto (__clone_internal)
+#endif
+
+#endif
diff --git a/include/libc-pointer-arith.h b/include/libc-pointer-arith.h
index 72e722c5aa..04ba537617 100644
--- a/include/libc-pointer-arith.h
+++ b/include/libc-pointer-arith.h
@@ -37,6 +37,9 @@
/* Cast an integer or a pointer VAL to integer with proper type. */
# define cast_to_integer(val) ((__integer_if_pointer_type (val)) (val))
+/* Cast an integer VAL to void * pointer. */
+# define cast_to_pointer(val) ((void *) (uintptr_t) (val))
+
/* Align a value by rounding down to closest size.
e.g. Using size of 4096, we get this behavior:
{4095, 4096, 4097} = {0, 4096, 4096}. */
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index fb155cf856..7c1f32b84d 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -54,6 +54,8 @@ CFLAGS-malloc.c += -DMORECORE_CLEARS=2
endif
ifeq ($(subdir),misc)
+gen-as-const-headers += clone-offsets.sym
+
sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
setfsuid setfsgid epoll_pwait signalfd \
eventfd eventfd_read eventfd_write prlimit \
@@ -64,7 +66,7 @@ sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
time64-support pselect32 \
xstat fxstat lxstat xstat64 fxstat64 lxstat64 \
fxstatat fxstatat64 \
- xmknod xmknodat
+ xmknod xmknodat clone3 clone-internal
CFLAGS-gethostid.c = -fexceptions
CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 220bb2dffe..299d4fef9c 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -179,6 +179,7 @@ libc {
__sigtimedwait;
# functions used by nscd
__netlink_assert_response;
+ __clone_internal;
}
}
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
new file mode 100644
index 0000000000..acafb78d81
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/clone-internal.c
@@ -0,0 +1,80 @@
+/* The internal wrapper of clone and clone3.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <sched.h>
+#include <clone3.h>
+#include <libc-pointer-arith.h> /* For cast_to_pointer. */
+#include <stackinfo.h> /* For _STACK_GROWS_{UP,DOWN}. */
+
+int
+__clone_internal (struct clone_args *cl_args,
+ int (*fn) (void *arg), void *arg)
+{
+ int ret;
+#ifdef CLONE_ARGS_SIZE_VER0
+ /* Try clone3 first. */
+ int saved_errno = errno;
+ ret = __clone3 (cl_args, fn, arg);
+ if (ret != -1 || errno != ENOSYS)
+ return ret;
+
+ /* NB: Restore errno since errno may be checked against non-zero
+ return value. */
+ __set_errno (saved_errno);
+#else
+ /* Check invalid arguments. */
+ if (cl_args == NULL || fn == NULL)
+ __set_errno (EINVAL);
+#endif
+
+ /* Check invalid clone3 specific bits. */
+ if ((cl_args->flags & CSIGNAL) != 0
+ || (cl_args->flags & __UINT64_C (0xffffffff00000000)))
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+
+ /* Map clone3 arguments to clone arguments. */
+ int flags = cl_args->flags | cl_args->exit_signal;
+ void *stack = cast_to_pointer (cl_args->stack);
+
+#ifdef __ia64__
+ ret = __clone2 (fn, stack, (size_t) cl_args->stack_size,
+ flags, arg,
+ cast_to_pointer (cl_args->parent_tid),
+ cast_to_pointer (cl_args->tls),
+ cast_to_pointer (cl_args->child_tid));
+#else
+# if !_STACK_GROWS_DOWN && !_STACK_GROWS_UP
+# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
+# endif
+
+# if _STACK_GROWS_DOWN
+ stack += cl_args->stack_size;
+# endif
+ ret = __clone (fn, stack, flags, arg,
+ cast_to_pointer (cl_args->parent_tid),
+ cast_to_pointer (cl_args->tls),
+ cast_to_pointer (cl_args->child_tid));
+#endif
+ return ret;
+}
+
+libc_hidden_def (__clone_internal)
diff --git a/sysdeps/unix/sysv/linux/clone-offsets.sym b/sysdeps/unix/sysv/linux/clone-offsets.sym
new file mode 100644
index 0000000000..d767e49fc8
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/clone-offsets.sym
@@ -0,0 +1,5 @@
+#include <clone3.h>
+
+--
+
+CLONE_ARGS_SIZE sizeof (struct clone_args)
diff --git a/sysdeps/unix/sysv/linux/clone3.c b/sysdeps/unix/sysv/linux/clone3.c
new file mode 100644
index 0000000000..b7a41f82e8
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/clone3.c
@@ -0,0 +1,34 @@
+/* The clone3 syscall wrapper.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <stddef.h>
+#include <clone3.h>
+
+int
+__clone3 (struct clone_args *cl_args, int (*fn) (void *arg), void *arg)
+{
+ if (cl_args == NULL || fn == NULL)
+ __set_errno (EINVAL);
+ else
+ __set_errno (ENOSYS);
+ return -1;
+}
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/clone3.h b/sysdeps/unix/sysv/linux/clone3.h
new file mode 100644
index 0000000000..be8a11a17c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/clone3.h
@@ -0,0 +1,58 @@
+/* The wrapper of clone3.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _CLONE3_H
+#define _CLONE3_H 1
+
+#include <features.h>
+#include <stdint.h>
+#define clone_args __redirect_clone_args
+#include <linux/sched.h>
+#undef clone_args
+
+__BEGIN_DECLS
+
+struct clone_args
+{
+ uint64_t flags; /* Flags bit mask. */
+ uint64_t pidfd; /* Where to store PID file descriptor
+ (pid_t *). */
+ uint64_t child_tid; /* Where to store child TID, in child's memory
+ (pid_t *). */
+ uint64_t parent_tid; /* Where to store child TID, in parent's memory
+ (int *). */
+ uint64_t exit_signal; /* Signal to deliver to parent on child
+ termination */
+ uint64_t stack; /* The lowest address of stack. */
+ uint64_t stack_size; /* Size of stack. */
+ uint64_t tls; /* Location of new TLS. */
+ uint64_t set_tid; /* Pointer to a pid_t array
+ (since Linux 5.5). */
+ uint64_t set_tid_size; /* Number of elements in set_tid
+ (since Linux 5.5). */
+ uint64_t cgroup; /* File descriptor for target cgroup
+ of child (since Linux 5.7). */
+};
+
+/* The wrapper of clone3. */
+extern int clone3 (struct clone_args *cl_args,
+ int (*__fn) (void *__arg), void *__arg);
+
+__END_DECLS
+
+#endif /* clone3.h */
diff --git a/sysdeps/unix/sysv/linux/createthread.c b/sysdeps/unix/sysv/linux/createthread.c
index bc3409b326..2b5e6cb131 100644
--- a/sysdeps/unix/sysv/linux/createthread.c
+++ b/sysdeps/unix/sysv/linux/createthread.c
@@ -18,6 +18,7 @@
<https://www.gnu.org/licenses/>. */
#include <sched.h>
+#include <clone3.h>
#include <setjmp.h>
#include <signal.h>
#include <stdlib.h>
@@ -28,12 +29,6 @@
#include <arch-fork.h>
-#ifdef __NR_clone2
-# define ARCH_CLONE __clone2
-#else
-# define ARCH_CLONE __clone
-#endif
-
/* See the comments in pthread_create.c for the requirements for these
two macros and the create_thread function. */
@@ -47,7 +42,8 @@ static int start_thread (void *arg) __attribute__ ((noreturn));
static int
create_thread (struct pthread *pd, const struct pthread_attr *attr,
- bool *stopped_start, STACK_VARIABLES_PARMS, bool *thread_ran)
+ bool *stopped_start, void *stackaddr, size_t stacksize,
+ bool *thread_ran)
{
/* Determine whether the newly created threads has to be started
stopped since we have to set the scheduling parameters or set the
@@ -100,9 +96,18 @@ create_thread (struct pthread *pd, const struct pthread_attr *attr,
TLS_DEFINE_INIT_TP (tp, pd);
- if (__glibc_unlikely (ARCH_CLONE (&start_thread, STACK_VARIABLES_ARGS,
- clone_flags, pd, &pd->tid, tp, &pd->tid)
- == -1))
+ struct clone_args args =
+ {
+ .flags = clone_flags,
+ .pidfd = (uintptr_t) &pd->tid,
+ .parent_tid = (uintptr_t) &pd->tid,
+ .child_tid = (uintptr_t) &pd->tid,
+ .stack = (uintptr_t) stackaddr,
+ .stack_size = stacksize,
+ .tls = (uintptr_t) tp,
+ };
+ int ret = __clone_internal (&args, &start_thread, pd);
+ if (__glibc_unlikely (ret == -1))
return errno;
/* It's started now, so if we fail below, we'll have to cancel it
diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
index 501f8fbccd..92b61e55d3 100644
--- a/sysdeps/unix/sysv/linux/spawni.c
+++ b/sysdeps/unix/sysv/linux/spawni.c
@@ -31,6 +31,7 @@
#include <dl-sysdep.h>
#include <libc-pointer-arith.h>
#include <ldsodefs.h>
+#include <clone3.h>
#include "spawn_int.h"
/* The Linux implementation of posix_spawn{p} uses the clone syscall directly
@@ -59,21 +60,6 @@
normal program exit with the exit code 127. */
#define SPAWN_ERROR 127
-#ifdef __ia64__
-# define CLONE(__fn, __stackbase, __stacksize, __flags, __args) \
- __clone2 (__fn, __stackbase, __stacksize, __flags, __args, 0, 0, 0)
-#else
-# define CLONE(__fn, __stack, __stacksize, __flags, __args) \
- __clone (__fn, __stack, __flags, __args)
-#endif
-
-/* Since ia64 wants the stackbase w/clone2, re-use the grows-up macro. */
-#if _STACK_GROWS_UP || defined (__ia64__)
-# define STACK(__stack, __stack_size) (__stack)
-#elif _STACK_GROWS_DOWN
-# define STACK(__stack, __stack_size) (__stack + __stack_size)
-#endif
-
struct posix_spawn_args
{
@@ -378,8 +364,14 @@ __spawnix (pid_t * pid, const char *file,
need for CLONE_SETTLS. Although parent and child share the same TLS
namespace, there will be no concurrent access for TLS variables (errno
for instance). */
- new_pid = CLONE (__spawni_child, STACK (stack, stack_size), stack_size,
- CLONE_VM | CLONE_VFORK | SIGCHLD, &args);
+ struct clone_args clone_args =
+ {
+ .flags = CLONE_VM | CLONE_VFORK,
+ .exit_signal = SIGCHLD,
+ .stack = (uintptr_t) stack,
+ .stack_size = stack_size,
+ };
+ new_pid = __clone_internal (&clone_args, __spawni_child, &args);
/* It needs to collect the case where the auxiliary process was created
but failed to execute the file (due either any preparation step or
diff --git a/sysdeps/unix/sysv/linux/tst-align-clone.c b/sysdeps/unix/sysv/linux/tst-align-clone.c
index 6ace61bac3..5a463e7af3 100644
--- a/sysdeps/unix/sysv/linux/tst-align-clone.c
+++ b/sysdeps/unix/sysv/linux/tst-align-clone.c
@@ -16,6 +16,7 @@
<https://www.gnu.org/licenses/>. */
#include <sched.h>
+#include <clone3.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
@@ -39,7 +40,7 @@ f (void *arg)
}
static int
-do_test (void)
+do_test_clone (bool use_clone_internal)
{
bool ok = true;
@@ -49,21 +50,41 @@ do_test (void)
ok = false;
#ifdef __ia64__
- extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
- size_t __child_stack_size, int __flags,
- void *__arg, ...);
- char st[256 * 1024];
- pid_t p = __clone2 (f, st, sizeof (st), 0, 0);
+# define STACK_SIZE 256 * 1024
+#else
+# define STACK_SIZE 128 * 1024
+#endif
+ char st[STACK_SIZE] __attribute__ ((aligned));
+
+ pid_t p;
+
+ if (use_clone_internal)
+ {
+ struct clone_args clone_args =
+ {
+ .stack = (uintptr_t) st,
+ .stack_size = sizeof (st),
+ };
+ p = __clone_internal (&clone_args, f, 0);
+ }
+ else
+ {
+#ifdef __ia64__
+ extern int __clone2 (int (*__fn) (void *__arg),
+ void *__child_stack_base,
+ size_t __child_stack_size, int __flags,
+ void *__arg, ...);
+ p = __clone2 (f, st, sizeof (st), 0, 0);
#else
- char st[128 * 1024] __attribute__ ((aligned));
# if _STACK_GROWS_DOWN
- pid_t p = clone (f, st + sizeof (st), 0, 0);
+ p = clone (f, st + sizeof (st), 0, 0);
# elif _STACK_GROWS_UP
- pid_t p = clone (f, st, 0, 0);
+ p = clone (f, st, 0, 0);
# else
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
# endif
#endif
+ }
if (p == -1)
{
printf("clone failed: %m\n");
@@ -91,5 +112,21 @@ do_test (void)
return ok ? 0 : 1;
}
+static int
+do_test (void)
+{
+ bool ok = true;
+
+ puts ("in main");
+
+ if (do_test_clone (false) != 0)
+ ok = false;
+
+ if (do_test_clone (true) != 0)
+ ok = false;
+
+ return ok ? 0 : 1;
+}
+
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
diff --git a/sysdeps/unix/sysv/linux/tst-clone.c b/sysdeps/unix/sysv/linux/tst-clone.c
index e6ae0106ef..855f48121e 100644
--- a/sysdeps/unix/sysv/linux/tst-clone.c
+++ b/sysdeps/unix/sysv/linux/tst-clone.c
@@ -22,6 +22,8 @@
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>
+#include <clone3.h>
+#include <stdbool.h>
#ifdef __ia64__
extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
@@ -35,14 +37,17 @@ int child_fn(void *arg)
}
static int
-do_test (void)
+do_test_clone (bool use_clone_internal)
{
int result;
+ if (use_clone_internal)
+ result = __clone_internal (NULL, child_fn, NULL);
+ else
#ifdef __ia64__
- result = __clone2 (child_fn, NULL, 0, 0, NULL, NULL, NULL);
+ result = __clone2 (child_fn, NULL, 0, 0, NULL, NULL, NULL);
#else
- result = clone (child_fn, NULL, 0, NULL);
+ result = clone (child_fn, NULL, 0, NULL);
#endif
if (errno != EINVAL || result != -1)
@@ -52,6 +57,18 @@ do_test (void)
return 1;
}
+ return 0;
+}
+
+static int
+do_test (void)
+{
+ if (do_test_clone (false) != 0)
+ return 1;
+
+ if (do_test_clone (true) != 0)
+ return 1;
+
puts ("All OK");
return 0;
}
diff --git a/sysdeps/unix/sysv/linux/tst-clone2.c b/sysdeps/unix/sysv/linux/tst-clone2.c
index ce36c70c0d..1df336f8c6 100644
--- a/sysdeps/unix/sysv/linux/tst-clone2.c
+++ b/sysdeps/unix/sysv/linux/tst-clone2.c
@@ -17,6 +17,7 @@
<https://www.gnu.org/licenses/>. */
#include <sched.h>
+#include <clone3.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
@@ -58,7 +59,7 @@ f (void *a)
static int
-do_test (void)
+do_test_clone (bool use_clone_internal)
{
sig = SIGRTMIN;
sigset_t ss;
@@ -70,23 +71,43 @@ do_test (void)
if (pipe2 (pipefd, O_CLOEXEC))
FAIL_EXIT1 ("pipe failed: %m");
- int clone_flags = 0;
#ifdef __ia64__
- extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
- size_t __child_stack_size, int __flags,
- void *__arg, ...);
- char st[256 * 1024] __attribute__ ((aligned));
- pid_t p = __clone2 (f, st, sizeof (st), clone_flags, 0);
-#else
- char st[128 * 1024] __attribute__ ((aligned));
-#if _STACK_GROWS_DOWN
- pid_t p = clone (f, st + sizeof (st), clone_flags, 0);
-#elif _STACK_GROWS_UP
- pid_t p = clone (f, st, clone_flags, 0);
+# define STACK_SIZE 256 * 1024
#else
-#error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
+# define STACK_SIZE 128 * 1024
#endif
+ char st[STACK_SIZE] __attribute__ ((aligned));
+
+ pid_t p;
+
+ if (use_clone_internal)
+ {
+ struct clone_args clone_args =
+ {
+ .stack = (uintptr_t) st,
+ .stack_size = sizeof (st),
+ };
+ p = __clone_internal (&clone_args, f, 0);
+ }
+ else
+ {
+ int clone_flags = 0;
+#ifdef __ia64__
+ extern int __clone2 (int (*__fn) (void *__arg),
+ void *__child_stack_base,
+ size_t __child_stack_size, int __flags,
+ void *__arg, ...);
+ p = __clone2 (f, st, sizeof (st), clone_flags, 0);
+#else
+# if _STACK_GROWS_DOWN
+ p = clone (f, st + sizeof (st), clone_flags, 0);
+# elif _STACK_GROWS_UP
+ p = clone (f, st, clone_flags, 0);
+# else
+# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
+# endif
#endif
+ }
close (pipefd[1]);
@@ -143,4 +164,16 @@ do_test (void)
return ret;
}
+static int
+do_test (void)
+{
+ if (do_test_clone (false) != 0)
+ return 1;
+
+ if (do_test_clone (true) != 0)
+ return 1;
+
+ return 0;
+}
+
#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/tst-clone3.c b/sysdeps/unix/sysv/linux/tst-clone3.c
index 1a1bfd4586..f4eabfc5a7 100644
--- a/sysdeps/unix/sysv/linux/tst-clone3.c
+++ b/sysdeps/unix/sysv/linux/tst-clone3.c
@@ -18,6 +18,8 @@
#include <string.h>
#include <sched.h>
+#include <clone3.h>
+#include <stdbool.h>
#include <signal.h>
#include <unistd.h>
#include <sys/syscall.h>
@@ -64,7 +66,7 @@ futex_wait (int *futexp, int val)
}
static int
-do_test (void)
+do_test_clone (bool use_clone_internal)
{
char st[1024] __attribute__ ((aligned));
int clone_flags = CLONE_THREAD;
@@ -78,23 +80,39 @@ do_test (void)
pid_t ctid = CTID_INIT_VAL;
pid_t tid;
+ if (use_clone_internal)
+ {
+ struct clone_args clone_args =
+ {
+ .flags = clone_flags & ~CSIGNAL,
+ .exit_signal = clone_flags & CSIGNAL,
+ .stack = (uintptr_t) st,
+ .stack_size = sizeof (st),
+ .child_tid = (uintptr_t) &ctid,
+ };
+ tid = __clone_internal (&clone_args, f, NULL);
+ }
+ else
+ {
#ifdef __ia64__
- extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
- size_t __child_stack_size, int __flags,
- void *__arg, ...);
- tid = __clone2 (f, st, sizeof (st), clone_flags, NULL, /* ptid */ NULL,
- /* tls */ NULL, &ctid);
-#else
-#if _STACK_GROWS_DOWN
- tid = clone (f, st + sizeof (st), clone_flags, NULL, /* ptid */ NULL,
- /* tls */ NULL, &ctid);
-#elif _STACK_GROWS_UP
- tid = clone (f, st, clone_flags, NULL, /* ptid */ NULL, /* tls */ NULL,
- &ctid);
+ extern int __clone2 (int (*__fn) (void *__arg),
+ void *__child_stack_base,
+ size_t __child_stack_size, int __flags,
+ void *__arg, ...);
+ tid = __clone2 (f, st, sizeof (st), clone_flags, NULL, /* ptid */ NULL,
+ /* tls */ NULL, &ctid);
#else
-#error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
-#endif
+# if _STACK_GROWS_DOWN
+ tid = clone (f, st + sizeof (st), clone_flags, NULL, /* ptid */ NULL,
+ /* tls */ NULL, &ctid);
+# elif _STACK_GROWS_UP
+ tid = clone (f, st, clone_flags, NULL, /* ptid */ NULL, /* tls */ NULL,
+ &ctid);
+# else
+# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
+# endif
#endif
+ }
if (tid == -1)
FAIL_EXIT1 ("clone failed: %m");
@@ -103,5 +121,17 @@ do_test (void)
return 2;
}
+static int
+do_test (void)
+{
+ if (do_test_clone (false) != 2)
+ return 1;
+
+ if (do_test_clone (true) != 2)
+ return 1;
+
+ return 2;
+}
+
#define EXPECTED_STATUS 2
#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/tst-getpid1.c b/sysdeps/unix/sysv/linux/tst-getpid1.c
index 253ebf2e15..1528743319 100644
--- a/sysdeps/unix/sysv/linux/tst-getpid1.c
+++ b/sysdeps/unix/sysv/linux/tst-getpid1.c
@@ -1,4 +1,6 @@
#include <sched.h>
+#include <clone3.h>
+#include <stdbool.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
@@ -27,7 +29,7 @@ f (void *a)
static int
-do_test (void)
+do_test_clone (bool use_clone_internal)
{
int mypid = getpid ();
@@ -42,21 +44,43 @@ do_test (void)
}
#ifdef __ia64__
- extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
- size_t __child_stack_size, int __flags,
- void *__arg, ...);
- char st[256 * 1024] __attribute__ ((aligned));
- pid_t p = __clone2 (f, st, sizeof (st), TEST_CLONE_FLAGS, 0);
+# define STACK_SIZE 256 * 1024
+#else
+# define STACK_SIZE 128 * 1024
+#endif
+ char st[STACK_SIZE] __attribute__ ((aligned));
+
+ pid_t p;
+
+ if (use_clone_internal)
+ {
+ struct clone_args clone_args =
+ {
+ .flags = TEST_CLONE_FLAGS & ~CSIGNAL,
+ .exit_signal = TEST_CLONE_FLAGS & CSIGNAL,
+ .stack = (uintptr_t) st,
+ .stack_size = sizeof (st),
+ };
+ p = __clone_internal (&clone_args, f, 0);
+ }
+ else
+ {
+#ifdef __ia64__
+ extern int __clone2 (int (*__fn) (void *__arg),
+ void *__child_stack_base,
+ size_t __child_stack_size, int __flags,
+ void *__arg, ...);
+ p = __clone2 (f, st, sizeof (st), TEST_CLONE_FLAGS, 0);
#else
- char st[128 * 1024] __attribute__ ((aligned));
# if _STACK_GROWS_DOWN
- pid_t p = clone (f, st + sizeof (st), TEST_CLONE_FLAGS, 0);
+ p = clone (f, st + sizeof (st), TEST_CLONE_FLAGS, 0);
# elif _STACK_GROWS_UP
- pid_t p = clone (f, st, TEST_CLONE_FLAGS, 0);
+ p = clone (f, st, TEST_CLONE_FLAGS, 0);
# else
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
# endif
#endif
+ }
if (p == -1)
{
printf("clone failed: %m\n");
@@ -118,5 +142,17 @@ do_test (void)
return 0;
}
+static int
+do_test (void)
+{
+ if (do_test_clone (false) != 0)
+ return 1;
+
+ if (do_test_clone (true) != 0)
+ return 1;
+
+ return 0;
+}
+
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
new file mode 100644
index 0000000000..8a7a9a7478
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S
@@ -0,0 +1,92 @@
+/* The clone3 syscall wrapper. Linux/x86-64 version.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+/* clone3() is even more special than fork() as it mucks with stacks
+ and invokes a function in the right context after its all over. */
+
+#include <sysdep.h>
+#include <clone-offsets.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, int (*fn)(void *arg),
+ void *arg);
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ rdi: cl_args
+ rsi: fn
+ rdx: arg
+
+ The kernel expects:
+ rax: system call number
+ rdi: cl_args
+ rsi: size */
+
+ .text
+ENTRY (__clone3)
+ /* Sanity check arguments. */
+ movq $-EINVAL, %rax
+ testq %rdi, %rdi /* No NULL cl_args pointer. */
+ jz SYSCALL_ERROR_LABEL
+ testq %rsi, %rsi /* No NULL function pointer. */
+ jz SYSCALL_ERROR_LABEL
+
+ /* Save the function pointer in R8 which is preserved by the
+ syscall. */
+ movq %rsi, %r8
+
+ /* Put sizeof (struct clone_args) in ESI. */
+ movl $CLONE_ARGS_SIZE , %esi
+
+ /* Do the system call. */
+ movl $SYS_ify(clone3), %eax
+
+ /* End FDE now, because in the child the unwind info will be
+ wrong. */
+ cfi_endproc
+ syscall
+
+ test %RAX_LP, %RAX_LP
+ jl SYSCALL_ERROR_LABEL
+ jz L(thread_start)
+
+ ret
+
+L(thread_start):
+ cfi_startproc
+ /* Clearing frame pointer is insufficient, use CFI. */
+ cfi_undefined (rip)
+ /* Clear the frame pointer. The ABI suggests this be done, to mark
+ the outermost frame obviously. */
+ xorl %ebp, %ebp
+
+ /* Set up arguments for the function call. */
+ movq %rdx, %rdi /* Argument. */
+ call *%r8 /* Call function. */
+ /* Call exit with return value from function call. */
+ movq %rax, %rdi
+ movl $SYS_ify(exit), %eax
+ syscall
+ cfi_endproc
+
+ cfi_startproc
+PSEUDO_END (__clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
--
2.31.1
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