diff options
| -rw-r--r-- | usr/src/lib/brand/lx/lx_brand/common/signal.c | 33 | ||||
| -rw-r--r-- | usr/src/lib/brand/lx/lx_brand/sys/lx_misc.h | 3 | ||||
| -rw-r--r-- | usr/src/uts/common/brand/lx/os/lx_brand.c | 12 | ||||
| -rw-r--r-- | usr/src/uts/common/brand/lx/sys/lx_brand.h | 2 |
4 files changed, 44 insertions, 6 deletions
diff --git a/usr/src/lib/brand/lx/lx_brand/common/signal.c b/usr/src/lib/brand/lx/lx_brand/common/signal.c index a8e3601cb9..b9356d16ab 100644 --- a/usr/src/lib/brand/lx/lx_brand/common/signal.c +++ b/usr/src/lib/brand/lx/lx_brand/common/signal.c @@ -1450,7 +1450,7 @@ lx_call_user_handler(int sig, siginfo_t *sip, void *p) { void (*user_handler)(); void (*stk_builder)(); - struct lx_sigaction *lxsap; + volatile struct lx_sigaction *lxsap; ucontext_t *ucp = (ucontext_t *)p; size_t stksize; int lx_sig; @@ -1480,9 +1480,30 @@ lx_call_user_handler(int sig, siginfo_t *sip, void *p) assert(0); } - if (lxsap->lxsa_handler == SIG_DFL || lxsap->lxsa_handler == SIG_IGN) + while (lxsap->lxsa_handler == SIG_DFL || + lxsap->lxsa_handler == SIG_IGN) { + /* + * This normally shouldn't be possible, but there is a window + * in which a vfork()'d process can have its signal disposition + * corrupted by its child. While this window is narrowed by + * blocking all signals in the brand, that leaves a (smaller) + * window whereby a signal in flight is delivered before the + * brand has blocked them. To detect this case, we will spin + * if our signal disposition is impossible and all signals are + * blocked due to vfork() activity: we know that the vfork()'d + * child will eventually restore the signal disposition before + * it unblocks signals, allowing us to proceed. + */ + if (lx_all_signals_blocked()) + continue; + + if (lxsap->lxsa_handler != SIG_DFL && + lxsap->lxsa_handler != SIG_IGN) + break; + lx_err_fatal("lxsa_handler set to %s? How?!?!?", (lxsap->lxsa_handler == SIG_DFL) ? "SIG_DFL" : "SIG_IGN"); + } #if defined(_LP64) stksize = sizeof (struct lx_sigstack); @@ -1506,7 +1527,7 @@ lx_call_user_handler(int sig, siginfo_t *sip, void *p) lxsap->lxsa_handler = SIG_DFL; lx_sigdeliver(lx_sig, sip, ucp, stksize, stk_builder, user_handler, - lxsap); + (struct lx_sigaction *)lxsap); /* * We need to handle restarting system calls if requested by the @@ -2390,3 +2411,9 @@ lx_unblock_all_signals() { (void) syscall(SYS_brand, B_UNBLOCK_ALL_SIGS); } + +int +lx_all_signals_blocked() +{ + return (syscall(SYS_brand, B_ALL_SIGS_BLOCKED)); +} diff --git a/usr/src/lib/brand/lx/lx_brand/sys/lx_misc.h b/usr/src/lib/brand/lx/lx_brand/sys/lx_misc.h index ce241db8bc..455ac174df 100644 --- a/usr/src/lib/brand/lx/lx_brand/sys/lx_misc.h +++ b/usr/src/lib/brand/lx/lx_brand/sys/lx_misc.h @@ -25,7 +25,7 @@ */ /* - * Copyright 2017 Joyent, Inc. + * Copyright 2018 Joyent, Inc. */ #ifndef _SYS_LX_H @@ -149,6 +149,7 @@ extern void lx_stack_postfork(void); extern void lx_block_all_signals(); extern void lx_unblock_all_signals(); +extern int lx_all_signals_blocked(); /* * NO_UUCOPY disables calls to the uucopy* system calls to help with diff --git a/usr/src/uts/common/brand/lx/os/lx_brand.c b/usr/src/uts/common/brand/lx/os/lx_brand.c index 974c8603e0..d388b14c70 100644 --- a/usr/src/uts/common/brand/lx/os/lx_brand.c +++ b/usr/src/uts/common/brand/lx/os/lx_brand.c @@ -25,7 +25,7 @@ */ /* - * Copyright 2017, Joyent, Inc. All rights reserved. + * Copyright 2018, Joyent, Inc. All rights reserved. */ /* @@ -1892,6 +1892,16 @@ lx_brandsys(int cmd, int64_t *rval, uintptr_t arg1, uintptr_t arg2, mutex_exit(&p->p_lock); return (result); } + + case B_ALL_SIGS_BLOCKED: { + uint_t result; + + mutex_enter(&p->p_lock); + pd = ptolxproc(p); + result = pd->l_block_all_signals; + mutex_exit(&p->p_lock); + return (result); + } } return (EINVAL); diff --git a/usr/src/uts/common/brand/lx/sys/lx_brand.h b/usr/src/uts/common/brand/lx/sys/lx_brand.h index e30568086d..9c1579cc82 100644 --- a/usr/src/uts/common/brand/lx/sys/lx_brand.h +++ b/usr/src/uts/common/brand/lx/sys/lx_brand.h @@ -103,7 +103,7 @@ extern "C" { #define B_STORE_ARGS 137 #define B_GETPID 138 #define B_JUMP_TO_LINUX 139 -/* formerly B_SET_THUNK_PID 140 */ +#define B_ALL_SIGS_BLOCKED 140 #define B_EXIT_AS_SIG 141 /* formerly B_HELPER_WAITID 142 */ #define B_HELPER_CLONE 143 |