[v5,0/5] Add an internal wrapper for clone, clone2 and clone3

Message ID 20210515123442.1432385-1-hjl.tools@gmail.com
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  • Add an internal wrapper for clone, clone2 and clone3
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Sunil Pandey via Libc-alpha May 15, 2021, 12:34 p.m.
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 (*__func) (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.
5. Call __clone3 if HAVE_CLONE3_WAPPER is defined.  If __clone3 returns
-1 with ENOSYS, fall back to clone or clone2.
6. Enable the public clone3 wrapper in the future after it has been
added to all targets.

Tested with build-many-glibcs.py.

H.J. Lu (5):
  Add an internal wrapper for clone, clone2 and clone3
  nptl: Always pass stack size to create_thread
  GLIBC_PRIVATE: Export __clone_internal
  x86-64: Add the clone3 wrapper
  Add tests for __clone_internal

 include/clone_internal.h                      |  14 ++
 include/libc-pointer-arith.h                  |   3 +
 nptl/allocatestack.c                          |  59 +-------
 nptl/createthread.c                           |   3 +-
 nptl/pthread_create.c                         |  17 ++-
 sysdeps/unix/sysv/linux/Makefile              |  11 +-
 sysdeps/unix/sysv/linux/Versions              |   1 +
 sysdeps/unix/sysv/linux/clone-internal.c      |  97 ++++++++++++
 sysdeps/unix/sysv/linux/clone-offsets.sym     |   5 +
 sysdeps/unix/sysv/linux/clone3.c              |   1 +
 sysdeps/unix/sysv/linux/clone3.h              |  55 +++++++
 sysdeps/unix/sysv/linux/createthread.c        |  25 +--
 sysdeps/unix/sysv/linux/spawni.c              |  26 ++--
 .../sysv/linux/tst-align-clone-internal.c     |  91 +++++++++++
 sysdeps/unix/sysv/linux/tst-clone-internal.c  |  51 +++++++
 sysdeps/unix/sysv/linux/tst-clone2-internal.c | 142 ++++++++++++++++++
 sysdeps/unix/sysv/linux/tst-clone3-internal.c | 101 +++++++++++++
 .../unix/sysv/linux/tst-getpid1-internal.c    | 137 +++++++++++++++++
 sysdeps/unix/sysv/linux/x86_64/clone3.S       |  92 ++++++++++++
 sysdeps/unix/sysv/linux/x86_64/sysdep.h       |   2 +
 20 files changed, 841 insertions(+), 92 deletions(-)
 create mode 100644 include/clone_internal.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/tst-align-clone-internal.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-clone-internal.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-clone2-internal.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-clone3-internal.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-getpid1-internal.c
 create mode 100644 sysdeps/unix/sysv/linux/x86_64/clone3.S

-- 
2.31.1