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- Fixes the bug with a fork()'d child's exception being caught in the parent process

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- Only looks for EXC_MASK_BAD_ACCESS, EXC_MASK_BAD_INSTRUCTION, and EXC_MASK_ARITHMETIC exceptions
- Adds try/catch blocks around "new" for bad_alloc
- Uses map.find() rather than map[] notation so as not to create extraneous objects
- Creates the exception watching thread as detached

r=mmentovai



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@117 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
waylonis 2007-02-05 18:49:44 +00:00
parent 3a9a38a29e
commit 600e56bc39
1 changed files with 61 additions and 29 deletions
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90
src/client/mac/handler/exception_handler.cc
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@ -224,12 +224,15 @@ kern_return_t ForwardException(mach_port_t task, mach_port_t failed_thread,
exception_type_t exception,
exception_data_t code,
mach_msg_type_number_t code_count) {
ExceptionParameters *previous = (*s_exception_parameter_map)[pthread_self()];
map<pthread_t, ExceptionParameters *>::iterator previous_location =
s_exception_parameter_map->find(pthread_self());
// If we don't have the previous data, we need to just exit
if (!previous)
if (previous_location == (*s_exception_parameter_map).end())
exit(exception);
ExceptionParameters *previous = (*previous_location).second;
// Find the first exception handler that matches the exception
unsigned int found;
for (found = 0; found < previous->count; ++found) {
@ -312,8 +315,14 @@ void *ExceptionHandler::WaitForMessage(void *exception_handler_class) {
// Save a pointer to our instance so that it will be available in the
// routines that are called from exc_server();
if (!s_exception_parameter_map)
s_exception_parameter_map = new map<pthread_t, ExceptionParameters *>;
if (!s_exception_parameter_map) {
try {
s_exception_parameter_map = new map<pthread_t, ExceptionParameters *>;
}
catch (std::bad_alloc) {
return NULL;
}
}
(*s_exception_parameter_map)[pthread_self()] = self->previous_;
@ -328,8 +337,10 @@ void *ExceptionHandler::WaitForMessage(void *exception_handler_class) {
if (result == KERN_SUCCESS) {
// Uninstall our handler so that we don't get in a loop if the process of
// writing out a minidump causes an exception.
self->UninstallHandler();
// writing out a minidump causes an exception. However, if the exception
// was caused by a fork'd process, don't uninstall things
if (receive.task.name == mach_task_self())
self->UninstallHandler();
// If the actual exception code is zero, then we're calling this handler
// in a way that indicates that we want to either exit this thread or
@ -344,21 +355,31 @@ void *ExceptionHandler::WaitForMessage(void *exception_handler_class) {
if (self->use_minidump_write_mutex_)
pthread_mutex_unlock(&self->minidump_write_mutex_);
} else {
// Generate the minidump with the exception data.
self->WriteMinidumpWithException(receive.exception, receive.code[0],
receive.thread.name);
// Pass along the exception to the server, which will setup the message
// and call catch_exception_raise() and put the KERN_SUCCESS into the
// reply.
ExceptionReplyMessage reply;
if (!exc_server(&receive.header, &reply.header))
exit(1);
// When forking a child process with the exception handler installed,
// if the child crashes, it will send the exception back to the parent
// process. The check for task == self_task() ensures that only
// exceptions that occur in the parent process are caught and
// processed.
if (receive.task.name == mach_task_self()) {
// Generate the minidump with the exception data.
self->WriteMinidumpWithException(receive.exception, receive.code[0],
receive.thread.name);
// Pass along the exception to the server, which will setup the
// message and call catch_exception_raise() and put the KERN_SUCCESS
// into the reply.
ExceptionReplyMessage reply;
if (!exc_server(&receive.header, &reply.header))
exit(1);
// Send a reply and exit
result = mach_msg(&(reply.header), MACH_SEND_MSG,
reply.header.msgh_size, 0, MACH_PORT_NULL,
MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
// Send a reply and exit
result = mach_msg(&(reply.header), MACH_SEND_MSG,
reply.header.msgh_size, 0, MACH_PORT_NULL,
MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
} else {
// An exception occurred in a child process
}
}
}
}
@ -367,12 +388,19 @@ void *ExceptionHandler::WaitForMessage(void *exception_handler_class) {
}
bool ExceptionHandler::InstallHandler() {
// Get the actual previous data
exception_mask_t exception_mask = EXC_MASK_ALL &
~(EXC_MASK_BREAKPOINT | EXC_MASK_MACH_SYSCALL |
EXC_MASK_SYSCALL | EXC_MASK_RPC_ALERT);
// Only catch these three exceptions. The other ones are nebulously defined
// and may result in treating a non-fatal exception as fatal.
exception_mask_t exception_mask = EXC_MASK_BAD_ACCESS |
EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC;
previous_ = new ExceptionParameters();
try {
previous_ = new ExceptionParameters();
}
catch (std::bad_alloc) {
return false;
}
// Save the current exception ports so that we can forward to them
previous_->count = EXC_TYPES_COUNT;
mach_port_t current_task = mach_task_self();
kern_return_t result = task_get_exception_ports(current_task, exception_mask,
@ -436,10 +464,14 @@ bool ExceptionHandler::Setup(bool install_handler) {
return false;
if (result == KERN_SUCCESS) {
// Install the handler in its own thread
if (pthread_create(&handler_thread_, NULL, &WaitForMessage, this) == 0) {
pthread_detach(handler_thread_);
}
// Install the handler in its own thread, detached as we won't be joining.
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
int thread_create_result = pthread_create(&handler_thread_, &attr,
&WaitForMessage, this);
pthread_attr_destroy(&attr);
result = thread_create_result ? KERN_FAILURE : KERN_SUCCESS;
}
return result == KERN_SUCCESS ? true : false;