Date: Tue, 27 Nov 2018 19:50:58 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r341094 - head/sys/kern Message-ID: <201811271950.wARJowtQ041214@repo.freebsd.org>
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Author: kib Date: Tue Nov 27 19:50:58 2018 New Revision: 341094 URL: https://svnweb.freebsd.org/changeset/base/341094 Log: Improve sigonstack(). Avoid relying on unsigned overflow for the test. Simplify expressions to avoid duplicate check for the range. Style. Add herald comment. Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D18361 Modified: head/sys/kern/kern_sig.c Modified: head/sys/kern/kern_sig.c ============================================================================== --- head/sys/kern/kern_sig.c Tue Nov 27 19:45:25 2018 (r341093) +++ head/sys/kern/kern_sig.c Tue Nov 27 19:50:58 2018 (r341094) @@ -615,20 +615,25 @@ signotify(struct thread *td) } } +/* + * Returns 1 (true) if altstack is configured for the thread, and the + * passed stack bottom address falls into the altstack range. Handles + * the 43 compat special case where the alt stack size is zero. + */ int sigonstack(size_t sp) { - struct thread *td = curthread; + struct thread *td; - return ((td->td_pflags & TDP_ALTSTACK) ? + td = curthread; + if ((td->td_pflags & TDP_ALTSTACK) == 0) + return (0); #if defined(COMPAT_43) - ((td->td_sigstk.ss_size == 0) ? - (td->td_sigstk.ss_flags & SS_ONSTACK) : - ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)) -#else - ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size) + if (td->td_sigstk.ss_size == 0) + return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0); #endif - : 0); + return (sp >= (size_t)td->td_sigstk.ss_sp && + sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp); } static __inline int
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