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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include <errno.h> | |
| 6 #include <pthread.h> | |
| 7 #include <signal.h> | |
| 8 | |
| 9 #include "components/nacl/loader/nonsfi/irt_interfaces.h" | |
| 10 #include "native_client/src/include/nacl_macros.h" | |
| 11 #include "native_client/src/shared/platform/nacl_log.h" | |
| 12 #include "native_client/src/trusted/service_runtime/nacl_exception.h" | |
| 13 #include "native_client/src/trusted/service_runtime/nacl_signal.h" | |
| 14 | |
| 15 namespace nacl { | |
| 16 namespace nonsfi { | |
| 17 namespace { | |
| 18 | |
| 19 // This is NonSFI version of exception handling codebase, NaCl side of | |
| 20 // things resides in: | |
| 21 // native_client/src/trusted/service_runtime/linux/nacl_signal.c | |
| 22 // native_client/src/trusted/service_runtime/sys_exception.c | |
| 23 | |
| 24 // Crash signals to handle. The differences from SFI NaCl are that | |
| 25 // NonSFI NaCl does not use NACL_THREAD_SUSPEND_SIGNAL (==SIGUSR1), | |
| 26 // and SIGSYS is reserved for seccomp-bpf. | |
| 27 const int kSignals[] = { | |
| 28 #if !defined(__mips__) | |
| 29 // This signal does not exist on MIPS. | |
| 30 SIGSTKFLT, | |
| 31 #endif | |
| 32 SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV, | |
| 33 // Handle SIGABRT in case someone sends it asynchronously using kill(). | |
| 34 SIGABRT | |
| 35 }; | |
| 36 | |
| 37 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; | |
| 38 NaClExceptionHandler signal_handler_function_pointer = NULL; | |
| 39 | |
| 40 // Signal handler, responsible for calling the registered handler. | |
| 41 void SignalCatch(int sig, siginfo_t* info, void* uc) { | |
| 42 if (signal_handler_function_pointer) { | |
| 43 NaClSignalContext signal_context; | |
| 44 NaClSignalContextFromHandler(&signal_context, uc); | |
| 45 NaClExceptionFrame exception_frame; | |
| 46 NaClSignalSetUpExceptionFrame(&exception_frame, | |
| 47 &signal_context, | |
| 48 0 /* context_user_addr, | |
| 49 not useful for NonSFI NaCl. */); | |
| 50 signal_handler_function_pointer(&exception_frame.context); | |
| 51 } | |
| 52 _exit(-sig); | |
| 53 } | |
| 54 | |
| 55 int IrtExceptionHandler(NaClExceptionHandler handler, | |
| 56 NaClExceptionHandler* old_handler) { | |
| 57 pthread_mutex_lock(&mutex); | |
| 58 if (old_handler) | |
| 59 *old_handler = signal_handler_function_pointer; | |
| 60 signal_handler_function_pointer = handler; | |
| 61 pthread_mutex_unlock(&mutex); | |
| 62 return 0; | |
| 63 } | |
| 64 | |
| 65 int IrtExceptionStack(void* stack, size_t size) { | |
| 66 // TODO(uekawa): Implement this function so that the exception stack | |
| 67 // actually gets used for running an exception handler. Currently | |
| 68 // we don't switch stack, which means we can't handle stack overflow | |
| 69 // exceptions. | |
| 70 return 0; | |
| 71 } | |
| 72 | |
| 73 int IrtExceptionClearFlag(void) { | |
| 74 // TODO(uekawa): Implement clear_flag() to behave like SFI NaCl's | |
| 75 // implementation, so that a thread can handle a second exception | |
| 76 // after handling a first exception | |
| 77 return ENOSYS; | |
| 78 } | |
| 79 | |
| 80 } // namespace | |
| 81 | |
| 82 const struct nacl_irt_exception_handling kIrtExceptionHandling = { | |
| 83 IrtExceptionHandler, | |
| 84 IrtExceptionStack, | |
| 85 IrtExceptionClearFlag, | |
| 86 }; | |
| 87 | |
| 88 void InitializeSignalHandler() { | |
| 89 struct sigaction sa; | |
| 90 unsigned int a; | |
| 91 | |
| 92 memset(&sa, 0, sizeof(sa)); | |
| 93 sigemptyset(&sa.sa_mask); | |
| 94 sa.sa_sigaction = SignalCatch; | |
| 95 sa.sa_flags = SA_ONSTACK | SA_SIGINFO; | |
| 96 | |
| 97 // Mask all signals we catch to prevent re-entry. | |
| 98 for (a = 0; a < NACL_ARRAY_SIZE(kSignals); a++) { | |
| 99 sigaddset(&sa.sa_mask, kSignals[a]); | |
| 100 } | |
| 101 | |
| 102 // Install all handlers. | |
| 103 for (a = 0; a < NACL_ARRAY_SIZE(kSignals); a++) { | |
| 104 if (sigaction(kSignals[a], &sa, NULL) != 0) | |
| 105 NaClLog(LOG_FATAL, "sigaction to register signals failed.\n"); | |
| 106 } | |
| 107 } | |
| 108 | |
| 109 } // namespace nonsfi | |
| 110 } // namespace nacl | |
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