sparc64: Remove unwind information from signal return stubs [BZ#31244]
[glibc.git] / sysdeps / unix / sysv / linux / clone-internal.c
blob40ef30303f848130fa469f1bd45a912ea215c4a4
1 /* The internal wrapper of clone and clone3.
2 Copyright (C) 2021-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
19 #include <sysdep.h>
20 #include <stddef.h>
21 #include <errno.h>
22 #include <sched.h>
23 #include <clone_internal.h>
24 #include <libc-pointer-arith.h> /* For cast_to_pointer. */
25 #include <stackinfo.h> /* For _STACK_GROWS_{UP,DOWN}. */
27 #define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
28 #define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
29 #define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
31 #define sizeof_field(TYPE, MEMBER) sizeof ((((TYPE *)0)->MEMBER))
32 #define offsetofend(TYPE, MEMBER) \
33 (offsetof (TYPE, MEMBER) + sizeof_field (TYPE, MEMBER))
35 _Static_assert (__alignof (struct clone_args) == 8,
36 "__alignof (struct clone_args) != 8");
37 _Static_assert (offsetofend (struct clone_args, tls) == CLONE_ARGS_SIZE_VER0,
38 "offsetofend (struct clone_args, tls) != CLONE_ARGS_SIZE_VER0");
39 _Static_assert (offsetofend (struct clone_args, set_tid_size) == CLONE_ARGS_SIZE_VER1,
40 "offsetofend (struct clone_args, set_tid_size) != CLONE_ARGS_SIZE_VER1");
41 _Static_assert (offsetofend (struct clone_args, cgroup) == CLONE_ARGS_SIZE_VER2,
42 "offsetofend (struct clone_args, cgroup) != CLONE_ARGS_SIZE_VER2");
43 _Static_assert (sizeof (struct clone_args) == CLONE_ARGS_SIZE_VER2,
44 "sizeof (struct clone_args) != CLONE_ARGS_SIZE_VER2");
46 int
47 __clone_internal_fallback (struct clone_args *cl_args,
48 int (*func) (void *arg), void *arg)
50 /* Map clone3 arguments to clone arguments. NB: No need to check
51 invalid clone3 specific bits in flags nor exit_signal since this
52 is an internal function. */
53 int flags = cl_args->flags | cl_args->exit_signal;
54 void *stack = cast_to_pointer (cl_args->stack);
55 int ret;
57 #if !_STACK_GROWS_DOWN && !_STACK_GROWS_UP
58 # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
59 #endif
61 #if _STACK_GROWS_DOWN
62 stack += cl_args->stack_size;
63 #endif
64 ret = __clone (func, stack, flags, arg,
65 cast_to_pointer (cl_args->parent_tid),
66 cast_to_pointer (cl_args->tls),
67 cast_to_pointer (cl_args->child_tid));
68 return ret;
71 int
72 __clone3_internal (struct clone_args *cl_args, int (*func) (void *args),
73 void *arg)
75 #ifdef HAVE_CLONE3_WRAPPER
76 # if __ASSUME_CLONE3
77 return __clone3 (cl_args, sizeof (*cl_args), func, arg);
78 # else
79 static int clone3_supported = 1;
80 if (atomic_load_relaxed (&clone3_supported) == 1)
82 int ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
83 if (ret != -1 || errno != ENOSYS)
84 return ret;
86 atomic_store_relaxed (&clone3_supported, 0);
88 # endif
89 #endif
90 __set_errno (ENOSYS);
91 return -1;
94 int
95 __clone_internal (struct clone_args *cl_args,
96 int (*func) (void *arg), void *arg)
98 #ifdef HAVE_CLONE3_WRAPPER
99 int saved_errno = errno;
100 int ret = __clone3_internal (cl_args, func, arg);
101 if (ret != -1 || errno != ENOSYS)
102 return ret;
104 /* NB: Restore errno since errno may be checked against non-zero
105 return value. */
106 __set_errno (saved_errno);
107 #endif
109 return __clone_internal_fallback (cl_args, func, arg);
112 libc_hidden_def (__clone_internal)