diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/clone-internal.c')
-rw-r--r-- | sysdeps/unix/sysv/linux/clone-internal.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c new file mode 100644 index 0000000000..1e7a8f6b35 --- /dev/null +++ b/sysdeps/unix/sysv/linux/clone-internal.c @@ -0,0 +1,91 @@ +/* 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 <sysdep.h> +#include <stddef.h> +#include <errno.h> +#include <sched.h> +#include <clone_internal.h> +#include <libc-pointer-arith.h> /* For cast_to_pointer. */ +#include <stackinfo.h> /* For _STACK_GROWS_{UP,DOWN}. */ + +#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */ +#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */ +#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */ + +#define sizeof_field(TYPE, MEMBER) sizeof ((((TYPE *)0)->MEMBER)) +#define offsetofend(TYPE, MEMBER) \ + (offsetof (TYPE, MEMBER) + sizeof_field (TYPE, MEMBER)) + +_Static_assert (__alignof (struct clone_args) == 8, + "__alignof (struct clone_args) != 8"); +_Static_assert (offsetofend (struct clone_args, tls) == CLONE_ARGS_SIZE_VER0, + "offsetofend (struct clone_args, tls) != CLONE_ARGS_SIZE_VER0"); +_Static_assert (offsetofend (struct clone_args, set_tid_size) == CLONE_ARGS_SIZE_VER1, + "offsetofend (struct clone_args, set_tid_size) != CLONE_ARGS_SIZE_VER1"); +_Static_assert (offsetofend (struct clone_args, cgroup) == CLONE_ARGS_SIZE_VER2, + "offsetofend (struct clone_args, cgroup) != CLONE_ARGS_SIZE_VER2"); +_Static_assert (sizeof (struct clone_args) == CLONE_ARGS_SIZE_VER2, + "sizeof (struct clone_args) != CLONE_ARGS_SIZE_VER2"); + +int +__clone_internal (struct clone_args *cl_args, + int (*func) (void *arg), void *arg) +{ + int ret; +#ifdef HAVE_CLONE3_WAPPER + /* Try clone3 first. */ + int saved_errno = errno; + ret = __clone3 (cl_args, sizeof (*cl_args), func, 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); +#endif + + /* Map clone3 arguments to clone arguments. NB: No need to check + invalid clone3 specific bits in flags nor exit_signal since this + is an internal function. */ + int flags = cl_args->flags | cl_args->exit_signal; + void *stack = cast_to_pointer (cl_args->stack); + +#ifdef __ia64__ + ret = __clone2 (func, stack, 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 (func, 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) |