diff options
Diffstat (limited to 'usr/src/lib/libc/port/threads/sigaction.c')
| -rw-r--r-- | usr/src/lib/libc/port/threads/sigaction.c | 74 |
1 files changed, 56 insertions, 18 deletions
diff --git a/usr/src/lib/libc/port/threads/sigaction.c b/usr/src/lib/libc/port/threads/sigaction.c index 1417c1e18a..8c48989a17 100644 --- a/usr/src/lib/libc/port/threads/sigaction.c +++ b/usr/src/lib/libc/port/threads/sigaction.c @@ -22,6 +22,7 @@ /* * Copyright 2010 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. + * Copyright 2015 Joyent, Inc. */ /* @@ -288,6 +289,24 @@ take_deferred_signal(int sig) thr_panic("take_deferred_signal(): __sigresend() failed"); } +/* + * sigacthandler() attempts to clean up dangling uc_link pointers in + * signal handling contexts when libc believes us to have escaped + * a signal handler incorrectly in the past. + * + * Branded processes have a legitimate use for a chain including contexts + * other than those used for signal handling when tracking emulation + * requests from the kernel. We allow them to disable this cleanup + * behaviour. + */ +static int escaped_context_cleanup = 1; + +void +set_escaped_context_cleanup(int on) +{ + escaped_context_cleanup = on; +} + void sigacthandler(int sig, siginfo_t *sip, void *uvp) { @@ -310,7 +329,7 @@ sigacthandler(int sig, siginfo_t *sip, void *uvp) * we are actually executing at main level (self->ul_siglink == NULL). * See the code for setjmp()/longjmp() for more details. */ - if (self->ul_siglink == NULL) + if (escaped_context_cleanup && self->ul_siglink == NULL) ucp->uc_link = NULL; /* @@ -462,11 +481,12 @@ sigaction(int sig, const struct sigaction *nact, struct sigaction *oact) } /* - * This is a private interface for the linux brand interface. + * This is a private interface for the lx brand. */ void setsigacthandler(void (*nsigacthandler)(int, siginfo_t *, void *), - void (**osigacthandler)(int, siginfo_t *, void *)) + void (**osigacthandler)(int, siginfo_t *, void *), + int (*brsetctxt)(const ucontext_t *)) { ulwp_t *self = curthread; uberdata_t *udp = self->ul_uberdata; @@ -475,6 +495,9 @@ setsigacthandler(void (*nsigacthandler)(int, siginfo_t *, void *), *osigacthandler = udp->sigacthandler; udp->sigacthandler = nsigacthandler; + + if (brsetctxt != NULL) + udp->setctxt = brsetctxt; } /* @@ -521,11 +544,39 @@ set_setcontext_enforcement(int on) setcontext_enforcement = on; } +/* + * The LX brand emulation library implements an operation that is analogous to + * setcontext(), but takes a different path in to the kernel. So that it can + * correctly restore a signal mask, we expose just the signal mask handling + * part of the regular setcontext() routine as a private interface. + */ +void +setcontext_sigmask(ucontext_t *ucp) +{ + ulwp_t *self = curthread; + + if (ucp->uc_flags & UC_SIGMASK) { + block_all_signals(self); + delete_reserved_signals(&ucp->uc_sigmask); + self->ul_sigmask = ucp->uc_sigmask; + if (self->ul_cursig) { + /* + * We have a deferred signal present. + * The signal mask will be set when the + * signal is taken in take_deferred_signal(). + */ + ASSERT(self->ul_critical + self->ul_sigdefer != 0); + ucp->uc_flags &= ~UC_SIGMASK; + } + } +} + #pragma weak _setcontext = setcontext int setcontext(const ucontext_t *ucp) { ulwp_t *self = curthread; + uberdata_t *udp = self->ul_uberdata; int ret; ucontext_t uc; @@ -540,20 +591,7 @@ setcontext(const ucontext_t *ucp) /* * Restore previous signal mask and context link. */ - if (uc.uc_flags & UC_SIGMASK) { - block_all_signals(self); - delete_reserved_signals(&uc.uc_sigmask); - self->ul_sigmask = uc.uc_sigmask; - if (self->ul_cursig) { - /* - * We have a deferred signal present. - * The signal mask will be set when the - * signal is taken in take_deferred_signal(). - */ - ASSERT(self->ul_critical + self->ul_sigdefer != 0); - uc.uc_flags &= ~UC_SIGMASK; - } - } + setcontext_sigmask(&uc); self->ul_siglink = uc.uc_link; /* @@ -588,7 +626,7 @@ setcontext(const ucontext_t *ucp) */ set_parking_flag(self, 0); self->ul_sp = 0; - ret = __setcontext(&uc); + ret = udp->setctxt(&uc); /* * It is OK for setcontext() to return if the user has not specified |