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| author | Konstantin Belousov <kib@FreeBSD.org> | 2018-11-27 19:50:58 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2018-11-27 19:50:58 +0000 |
| commit | affd918514794a231cd571d0d15c9cfaf4a2a6f4 (patch) | |
| tree | 9a14dd73b0147397866e7a8faec28c2347149988 /sys/kern | |
| parent | b307954481a13a501bf9f315d160ff768174feff (diff) | |
| download | src-affd918514794a231cd571d0d15c9cfaf4a2a6f4.tar.gz src-affd918514794a231cd571d0d15c9cfaf4a2a6f4.zip | |
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
Notes
Notes:
svn path=/head/; revision=341094
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_sig.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index 0817bb618c1c..2ed7d36f2c33 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -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 |