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98f9435f33
Add an optimization to avoid calling clone3 when glibc detects that there is no kernel support. It also adds __ASSUME_CLONE3, which allows skipping this optimization and issuing the clone3 syscall directly. It does not handle the the small window between 5.3 and 5.5 for posix_spawn (CLONE_CLEAR_SIGHAND was added in 5.5). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
44 lines
1.7 KiB
C
44 lines
1.7 KiB
C
#ifndef _CLONE_INTERNAL_H
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#define _CLONE_INTERNAL_H
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#include <clone3.h>
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/* The clone3 syscall provides a superset of the functionality of the clone
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interface. The kernel might extend __CL_ARGS struct in the future, with
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each version with a diffent __SIZE. If the child is created, it will
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start __FUNC function with __ARG arguments.
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Different than kernel, the implementation also returns EINVAL for an
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invalid NULL __CL_ARGS or __FUNC (similar to __clone).
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All callers are responsible for correctly aligning the stack. The stack is
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not aligned prior to the syscall (this differs from the exported __clone).
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This function is only implemented if the ABI defines HAVE_CLONE3_WRAPPER.
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*/
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extern int __clone3 (struct clone_args *__cl_args, size_t __size,
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int (*__func) (void *__arg), void *__arg);
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/* The internal wrapper of clone/clone2 and clone3. Different than __clone3,
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it will align the stack if required. If __clone3 returns -1 with ENOSYS,
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fall back to clone or clone2. */
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extern int __clone_internal (struct clone_args *__cl_args,
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int (*__func) (void *__arg), void *__arg);
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/* clone3 wrapper with a sticky check to avoid re-issuing the syscall if
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it fails with ENOSYS. */
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extern int __clone3_internal (struct clone_args *cl_args,
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int (*func) (void *args), void *arg)
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attribute_hidden;
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/* The fallback code which calls clone/clone2 based on clone3 arguments. */
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extern int __clone_internal_fallback (struct clone_args *__cl_args,
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int (*__func) (void *__arg),
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void *__arg)
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attribute_hidden;
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#ifndef _ISOMAC
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libc_hidden_proto (__clone3)
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libc_hidden_proto (__clone_internal)
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#endif
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#endif
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