3b78cc7c0f
check_deferred_signal() returns twice, since handle_signal() emulates the return from the normal signal handler by sigreturn(2)ing the passed context. Second return is performed on the destroyed stack frame, because __fillcontextx() has already returned. This causes undefined and bad behaviour, usually the victim thread gets SIGSEGV. Avoid nested frame and the need to return from it by doing direct call to getcontext() in the check_deferred_signal() and using a new private libc helper __fillcontextx2() to complement the context with the extended CPU state if the deferred signal is still present. The __fillcontextx() is now unused, but is kept to allow older libthr.so to be used with the new libc. Mark __fillcontextx() as returning twice [1]. Reported by: pgj Pointy hat to: kib Discussed with: dim Tested by: pgj, dim Suggested by: jilles [1] MFC after: 1 week
107 lines
3.3 KiB
C
107 lines
3.3 KiB
C
/*-
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* Copyright (c) 1999 Marcel Moolenaar
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_UCONTEXT_H_
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#define _SYS_UCONTEXT_H_
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#include <sys/signal.h>
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#include <machine/ucontext.h>
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typedef struct __ucontext {
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/*
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* Keep the order of the first two fields. Also,
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* keep them the first two fields in the structure.
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* This way we can have a union with struct
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* sigcontext and ucontext_t. This allows us to
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* support them both at the same time.
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* note: the union is not defined, though.
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*/
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sigset_t uc_sigmask;
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mcontext_t uc_mcontext;
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struct __ucontext *uc_link;
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stack_t uc_stack;
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int uc_flags;
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#define UCF_SWAPPED 0x00000001 /* Used by swapcontext(3). */
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int __spare__[4];
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} ucontext_t;
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#if defined(_KERNEL) && defined(COMPAT_FREEBSD4)
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#if defined(__i386__)
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struct ucontext4 {
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sigset_t uc_sigmask;
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struct mcontext4 uc_mcontext;
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struct ucontext4 *uc_link;
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stack_t uc_stack;
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int __spare__[8];
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};
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#else /* __i386__ */
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#define ucontext4 ucontext
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#endif /* __i386__ */
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#endif /* _KERNEL */
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#ifndef _KERNEL
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__BEGIN_DECLS
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int getcontext(ucontext_t *) __returns_twice;
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ucontext_t *getcontextx(void);
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int setcontext(const ucontext_t *);
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void makecontext(ucontext_t *, void (*)(void), int, ...);
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int signalcontext(ucontext_t *, int, __sighandler_t *);
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int swapcontext(ucontext_t *, const ucontext_t *);
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#if __BSD_VISIBLE
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int __getcontextx_size(void);
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int __fillcontextx(char *ctx) __returns_twice;
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int __fillcontextx2(char *ctx);
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#endif
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__END_DECLS
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#else /* _KERNEL */
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struct thread;
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/*
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* Flags for get_mcontext(). The low order 4 bits (i.e a mask of 0x0f) are
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* reserved for use by machine independent code. All other bits are for use
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* by machine dependent code.
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*/
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#define GET_MC_CLEAR_RET 1
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/* Machine-dependent functions: */
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int get_mcontext(struct thread *, mcontext_t *, int);
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int set_mcontext(struct thread *, const mcontext_t *);
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#endif /* !_KERNEL */
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#endif /* !_SYS_UCONTEXT_H_ */
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