[compiler-rt] r192686 - tsan: implement internal syscall-based versions of sigaction/sigprocmask
Alexey Samsonov
samsonov at google.com
Tue Oct 15 05:13:09 PDT 2013
On Tue, Oct 15, 2013 at 4:09 PM, Dmitry Vyukov <dvyukov at google.com> wrote:
> the following lives in sanitizer_linux.h:
>
> uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int
> count);
> uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr
> arg5);
> uptr internal_sigaltstack(const struct sigaltstack* ss,
> struct sigaltstack* oss);
>
> sigaction naturally fits here
>
I disagree. I find it more convenient to have all re-definitions of POSIX
structures in one place. Also,
sanitizer_platform_limits_posix.cc has some useful compiler checks
verifying that our re-definitions of
POSIX structs are actually correct.
>
>
>
> On Tue, Oct 15, 2013 at 4:03 PM, Alexey Samsonov <samsonov at google.com>
> wrote:
> >
> > On Tue, Oct 15, 2013 at 3:31 PM, Dmitry Vyukov <dvyukov at google.com>
> wrote:
> >>
> >> Author: dvyukov
> >> Date: Tue Oct 15 06:31:51 2013
> >> New Revision: 192686
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=192686&view=rev
> >> Log:
> >> tsan: implement internal syscall-based versions of sigaction/sigprocmask
> >> use them in stoptheworld
> >> fixes applications that intercept sigaction/sigprocmask
> >>
> >>
> >>
> >> Modified:
> >> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_syscalls.inc
> >> compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
> >> compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h
> >>
> >>
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
> >>
> >> Modified:
> >> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_syscalls.inc
> >> URL:
> >>
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_syscalls.inc?rev=192686&r1=192685&r2=192686&view=diff
> >>
> >>
> ==============================================================================
> >> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_syscalls.inc
> >> (original)
> >> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_syscalls.inc
> >> Tue Oct 15 06:31:51 2013
> >> @@ -37,6 +37,7 @@
> >> #if SANITIZER_LINUX
> >>
> >> #include "sanitizer_libc.h"
> >> +#include "sanitizer_linux.h"
> >>
> >> #define PRE_SYSCALL(name)
> >> \
> >> SANITIZER_INTERFACE_ATTRIBUTE void
> __sanitizer_syscall_pre_impl_##name
> >> @@ -103,10 +104,6 @@ struct sanitizer_kernel_sockaddr {
> >> char sa_data[14];
> >> };
> >>
> >> -// Real sigset size is always passed as a syscall argument.
> >> -// Declare it "void" to catch sizeof(kernel_sigset_t).
> >> -typedef void kernel_sigset_t;
> >> -
> >> static void kernel_write_iovec(const __sanitizer_iovec *iovec,
> >> SIZE_T iovlen, SIZE_T maxlen) {
> >> for (SIZE_T i = 0; i < iovlen && maxlen; ++i) {
> >>
> >> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
> >> URL:
> >>
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc?rev=192686&r1=192685&r2=192686&view=diff
> >>
> >>
> ==============================================================================
> >> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc (original)
> >> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc Tue Oct 15
> >> 06:31:51 2013
> >> @@ -602,6 +602,31 @@ uptr internal_sigaltstack(const struct s
> >> return internal_syscall(__NR_sigaltstack, ss, oss);
> >> }
> >>
> >> +uptr internal_sigaction(int signum, const kernel_sigaction_t *act,
> >> + struct kernel_sigaction_t *oldact) {
> >> + return internal_syscall(__NR_rt_sigaction, signum, act, oldact,
> >> + sizeof(kernel_sigset_t));
> >> +}
> >> +
> >> +uptr internal_sigprocmask(int how, kernel_sigset_t *set,
> >> + kernel_sigset_t *oldset) {
> >> + return internal_syscall(__NR_rt_sigprocmask, (uptr)how, &set->sig[0],
> >> + &oldset->sig[0], sizeof(kernel_sigset_t));
> >> +}
> >> +
> >> +void internal_sigfillset(kernel_sigset_t *set) {
> >> + internal_memset(set, 0xff, sizeof(*set));
> >> +}
> >> +
> >> +void internal_sigdelset(kernel_sigset_t *set, int signum) {
> >> + signum -= 1;
> >> + CHECK_GE(signum, 0);
> >> + CHECK_LT(signum, sizeof(*set) * 8);
> >> + const uptr idx = signum / (sizeof(set->sig[0]) * 8);
> >> + const uptr bit = signum % (sizeof(set->sig[0]) * 8);
> >> + set->sig[idx] &= ~(1 << bit);
> >> +}
> >> +
> >> // ThreadLister implementation.
> >> ThreadLister::ThreadLister(int pid)
> >> : pid_(pid),
> >>
> >> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h
> >> URL:
> >>
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h?rev=192686&r1=192685&r2=192686&view=diff
> >>
> >>
> ==============================================================================
> >> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h (original)
> >> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h Tue Oct 15
> >> 06:31:51 2013
> >> @@ -20,17 +20,39 @@
> >>
> >> struct link_map; // Opaque type returned by dlopen().
> >> struct sigaltstack;
> >> +typedef struct siginfo siginfo_t;
> >>
> >> namespace __sanitizer {
> >> // Dirent structure for getdents(). Note that this structure is
> different
> >> from
> >> // the one in <dirent.h>, which is used by readdir().
> >> struct linux_dirent;
> >>
> >> +struct kernel_sigset_t {
> >> + u8 sig[FIRST_32_SECOND_64(16, 8)];
> >> +};
> >> +
> >> +struct kernel_sigaction_t {
> >> + union {
> >> + void (*sigaction)(int signo, siginfo_t *info, void *ctx);
> >> + void (*handler)(int signo);
> >> + };
> >> + unsigned long sa_flags;
> >> + void (*sa_restorer)(void);
> >> + kernel_sigset_t sa_mask;
> >> +};
> >
> >
> > Hm... Consider moving this to sanitizer_platform_limits_posix.(h|cc).
> > I think that's where we collect definitions of OS-specific structures.
> >
> >>
> >> +
> >> // Syscall wrappers.
> >> uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int
> >> count);
> >> uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr
> >> arg5);
> >> uptr internal_sigaltstack(const struct sigaltstack* ss,
> >> struct sigaltstack* oss);
> >> +uptr internal_sigaction(int signum, const kernel_sigaction_t *act,
> >> + kernel_sigaction_t *oldact);
> >> +uptr internal_sigprocmask(int how, kernel_sigset_t *set,
> >> + kernel_sigset_t *oldset);
> >> +void internal_sigfillset(kernel_sigset_t *set);
> >> +void internal_sigdelset(kernel_sigset_t *set, int signum);
> >> +
> >> #ifdef __x86_64__
> >> uptr internal_clone(int (*fn)(void *), void *child_stack, int flags,
> void
> >> *arg,
> >> int *parent_tidptr, void *newtls, int
> *child_tidptr);
> >>
> >> Modified:
> >>
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
> >> URL:
> >>
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc?rev=192686&r1=192685&r2=192686&view=diff
> >>
> >>
> ==============================================================================
> >> ---
> >>
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
> >> (original)
> >> +++
> >>
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
> >> Tue Oct 15 06:31:51 2013
> >> @@ -252,12 +252,12 @@ static int TracerThread(void* argument)
> >> // the mask we inherited from the caller thread.
> >> for (uptr signal_index = 0; signal_index <
> >> ARRAY_SIZE(kUnblockedSignals);
> >> signal_index++) {
> >> - struct sigaction new_sigaction;
> >> + kernel_sigaction_t new_sigaction;
> >> internal_memset(&new_sigaction, 0, sizeof(new_sigaction));
> >> - new_sigaction.sa_sigaction = TracerThreadSignalHandler;
> >> + new_sigaction.sigaction = TracerThreadSignalHandler;
> >> new_sigaction.sa_flags = SA_ONSTACK | SA_SIGINFO;
> >> - sigfillset(&new_sigaction.sa_mask);
> >> - sigaction(kUnblockedSignals[signal_index], &new_sigaction, NULL);
> >> + internal_sigfillset(&new_sigaction.sa_mask);
> >> + internal_sigaction(kUnblockedSignals[signal_index], &new_sigaction,
> >> NULL);
> >> }
> >>
> >> int exit_code = 0;
> >> @@ -307,9 +307,9 @@ NOINLINE static void WipeStack() {
> >>
> >> // We have a limitation on the stack frame size, so some stuff had to
> be
> >> moved
> >> // into globals.
> >> -static sigset_t blocked_sigset;
> >> -static sigset_t old_sigset;
> >> -static struct sigaction old_sigactions[ARRAY_SIZE(kUnblockedSignals)];
> >> +static kernel_sigset_t blocked_sigset;
> >> +static kernel_sigset_t old_sigset;
> >> +static kernel_sigaction_t
> old_sigactions[ARRAY_SIZE(kUnblockedSignals)];
> >>
> >> class StopTheWorldScope {
> >> public:
> >> @@ -323,21 +323,21 @@ class StopTheWorldScope {
> >> // We cannot allow user-defined handlers to run while the
> >> ThreadSuspender
> >> // thread is active, because they could conceivably call some libc
> >> functions
> >> // which modify errno (which is shared between the two threads).
> >> - sigfillset(&blocked_sigset);
> >> + internal_sigfillset(&blocked_sigset);
> >> for (uptr signal_index = 0; signal_index <
> >> ARRAY_SIZE(kUnblockedSignals);
> >> signal_index++) {
> >> // Remove the signal from the set of blocked signals.
> >> - sigdelset(&blocked_sigset, kUnblockedSignals[signal_index]);
> >> + internal_sigdelset(&blocked_sigset,
> >> kUnblockedSignals[signal_index]);
> >> // Install the default handler.
> >> - struct sigaction new_sigaction;
> >> + kernel_sigaction_t new_sigaction;
> >> internal_memset(&new_sigaction, 0, sizeof(new_sigaction));
> >> - new_sigaction.sa_handler = SIG_DFL;
> >> - sigfillset(&new_sigaction.sa_mask);
> >> - sigaction(kUnblockedSignals[signal_index], &new_sigaction,
> >> + new_sigaction.handler = SIG_DFL;
> >> + internal_sigfillset(&new_sigaction.sa_mask);
> >> + internal_sigaction(kUnblockedSignals[signal_index],
> &new_sigaction,
> >> &old_sigactions[signal_index]);
> >> }
> >> int sigprocmask_status =
> >> - sigprocmask(SIG_BLOCK, &blocked_sigset, &old_sigset);
> >> + internal_sigprocmask(SIG_BLOCK, &blocked_sigset, &old_sigset);
> >> CHECK_EQ(sigprocmask_status, 0); // sigprocmask should never fail
> >> // Make this process dumpable. Processes that are not dumpable
> cannot
> >> be
> >> // attached to.
> >> @@ -355,10 +355,10 @@ class StopTheWorldScope {
> >> // Restore the signal handlers.
> >> for (uptr signal_index = 0; signal_index <
> >> ARRAY_SIZE(kUnblockedSignals);
> >> signal_index++) {
> >> - sigaction(kUnblockedSignals[signal_index],
> >> + internal_sigaction(kUnblockedSignals[signal_index],
> >> &old_sigactions[signal_index], NULL);
> >> }
> >> - sigprocmask(SIG_SETMASK, &old_sigset, &old_sigset);
> >> + internal_sigprocmask(SIG_SETMASK, &old_sigset, &old_sigset);
> >> }
> >>
> >> private:
> >>
> >>
> >> _______________________________________________
> >> llvm-commits mailing list
> >> llvm-commits at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >
> >
> >
> >
> > --
> > Alexey Samsonov, MSK
>
--
Alexey Samsonov, MSK
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