| /* |
| * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "runtime/interfaceSupport.hpp" |
| #include "runtime/os.inline.hpp" |
| #include "services/attachListener.hpp" |
| #include "services/dtraceAttacher.hpp" |
| #include "utilities/vmError.hpp" |
| |
| #include <door.h> |
| #include <limits.h> |
| #include <string.h> |
| #include <signal.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| |
| // stropts.h uses STR in stream ioctl defines |
| #undef STR |
| #include <stropts.h> |
| #undef STR |
| #define STR(a) #a |
| |
| // The attach mechanism on Solaris is implemented using the Doors IPC |
| // mechanism. The first tool to attempt to attach causes the attach |
| // listener thread to startup. This thread creats a door that is |
| // associated with a function that enqueues an operation to the attach |
| // listener. The door is attached to a file in the file system so that |
| // client (tools) can locate it. To enqueue an operation to the VM the |
| // client calls through the door which invokes the enqueue function in |
| // this process. The credentials of the client are checked and if the |
| // effective uid matches this process then the operation is enqueued. |
| // When an operation completes the attach listener is required to send the |
| // operation result and any result data to the client. In this implementation |
| // the result is returned via a UNIX domain socket. A pair of connected |
| // sockets (socketpair) is created in the enqueue function and the file |
| // descriptor for one of the sockets is returned to the client as the |
| // return from the door call. The other end is retained in this process. |
| // When the operation completes the result is sent to the client and |
| // the socket is closed. |
| |
| // forward reference |
| class SolarisAttachOperation; |
| |
| class SolarisAttachListener: AllStatic { |
| private: |
| |
| // the path to which we attach the door file descriptor |
| static char _door_path[PATH_MAX+1]; |
| static volatile bool _has_door_path; |
| |
| // door descriptor returned by door_create |
| static int _door_descriptor; |
| |
| static void set_door_path(char* path) { |
| if (path == NULL) { |
| _has_door_path = false; |
| } else { |
| strncpy(_door_path, path, PATH_MAX); |
| _door_path[PATH_MAX] = '\0'; // ensure it's nul terminated |
| _has_door_path = true; |
| } |
| } |
| |
| static void set_door_descriptor(int dd) { _door_descriptor = dd; } |
| |
| // mutex to protect operation list |
| static mutex_t _mutex; |
| |
| // semaphore to wakeup listener thread |
| static sema_t _wakeup; |
| |
| static mutex_t* mutex() { return &_mutex; } |
| static sema_t* wakeup() { return &_wakeup; } |
| |
| // enqueued operation list |
| static SolarisAttachOperation* _head; |
| static SolarisAttachOperation* _tail; |
| |
| static SolarisAttachOperation* head() { return _head; } |
| static void set_head(SolarisAttachOperation* head) { _head = head; } |
| |
| static SolarisAttachOperation* tail() { return _tail; } |
| static void set_tail(SolarisAttachOperation* tail) { _tail = tail; } |
| |
| // create the door |
| static int create_door(); |
| |
| public: |
| enum { |
| ATTACH_PROTOCOL_VER = 1 // protocol version |
| }; |
| enum { |
| ATTACH_ERROR_BADREQUEST = 100, // error code returned by |
| ATTACH_ERROR_BADVERSION = 101, // the door call |
| ATTACH_ERROR_RESOURCE = 102, |
| ATTACH_ERROR_INTERNAL = 103, |
| ATTACH_ERROR_DENIED = 104 |
| }; |
| |
| // initialize the listener |
| static int init(); |
| |
| static bool has_door_path() { return _has_door_path; } |
| static char* door_path() { return _door_path; } |
| static int door_descriptor() { return _door_descriptor; } |
| |
| // enqueue an operation |
| static void enqueue(SolarisAttachOperation* op); |
| |
| // dequeue an operation |
| static SolarisAttachOperation* dequeue(); |
| }; |
| |
| |
| // SolarisAttachOperation is an AttachOperation that additionally encapsulates |
| // a socket connection to the requesting client/tool. SolarisAttachOperation |
| // can additionally be held in a linked list. |
| |
| class SolarisAttachOperation: public AttachOperation { |
| private: |
| friend class SolarisAttachListener; |
| |
| // connection to client |
| int _socket; |
| |
| // linked list support |
| SolarisAttachOperation* _next; |
| |
| SolarisAttachOperation* next() { return _next; } |
| void set_next(SolarisAttachOperation* next) { _next = next; } |
| |
| public: |
| void complete(jint res, bufferedStream* st); |
| |
| int socket() const { return _socket; } |
| void set_socket(int s) { _socket = s; } |
| |
| SolarisAttachOperation(char* name) : AttachOperation(name) { |
| set_socket(-1); |
| set_next(NULL); |
| } |
| }; |
| |
| // statics |
| char SolarisAttachListener::_door_path[PATH_MAX+1]; |
| volatile bool SolarisAttachListener::_has_door_path; |
| int SolarisAttachListener::_door_descriptor = -1; |
| mutex_t SolarisAttachListener::_mutex; |
| sema_t SolarisAttachListener::_wakeup; |
| SolarisAttachOperation* SolarisAttachListener::_head = NULL; |
| SolarisAttachOperation* SolarisAttachListener::_tail = NULL; |
| |
| // Supporting class to help split a buffer into individual components |
| class ArgumentIterator : public StackObj { |
| private: |
| char* _pos; |
| char* _end; |
| public: |
| ArgumentIterator(char* arg_buffer, size_t arg_size) { |
| _pos = arg_buffer; |
| _end = _pos + arg_size - 1; |
| } |
| char* next() { |
| if (*_pos == '\0') { |
| return NULL; |
| } |
| char* res = _pos; |
| char* next_pos = strchr(_pos, '\0'); |
| if (next_pos < _end) { |
| next_pos++; |
| } |
| _pos = next_pos; |
| return res; |
| } |
| }; |
| |
| // Calls from the door function to check that the client credentials |
| // match this process. Returns 0 if credentials okay, otherwise -1. |
| static int check_credentials() { |
| ucred_t *cred_info = NULL; |
| int ret = -1; // deny by default |
| |
| // get client credentials |
| if (door_ucred(&cred_info) == -1) { |
| return -1; // unable to get them, deny |
| } |
| |
| // get our euid/eguid (probably could cache these) |
| uid_t euid = geteuid(); |
| gid_t egid = getegid(); |
| |
| // get euid/egid from ucred_free |
| uid_t ucred_euid = ucred_geteuid(cred_info); |
| gid_t ucred_egid = ucred_getegid(cred_info); |
| |
| // check that the effective uid/gid matches |
| if (ucred_euid == euid && ucred_egid == egid) { |
| ret = 0; // allow |
| } |
| |
| ucred_free(cred_info); |
| return ret; |
| } |
| |
| |
| // Parses the argument buffer to create an AttachOperation that we should |
| // enqueue to the attach listener. |
| // The buffer is expected to be formatted as follows: |
| // <ver>0<cmd>0<arg>0<arg>0<arg>0 |
| // where <ver> is the version number (must be "1"), <cmd> is the command |
| // name ("load, "datadump", ...) and <arg> is an argument. |
| // |
| static SolarisAttachOperation* create_operation(char* argp, size_t arg_size, int* err) { |
| // assume bad request until parsed |
| *err = SolarisAttachListener::ATTACH_ERROR_BADREQUEST; |
| |
| if (arg_size < 2 || argp[arg_size-1] != '\0') { |
| return NULL; // no ver or not null terminated |
| } |
| |
| // Use supporting class to iterate over the buffer |
| ArgumentIterator args(argp, arg_size); |
| |
| // First check the protocol version |
| char* ver = args.next(); |
| if (ver == NULL) { |
| return NULL; |
| } |
| if (atoi(ver) != SolarisAttachListener::ATTACH_PROTOCOL_VER) { |
| *err = SolarisAttachListener::ATTACH_ERROR_BADVERSION; |
| return NULL; |
| } |
| |
| // Get command name and create the operation |
| char* name = args.next(); |
| if (name == NULL || strlen(name) > AttachOperation::name_length_max) { |
| return NULL; |
| } |
| SolarisAttachOperation* op = new SolarisAttachOperation(name); |
| |
| // Iterate over the arguments |
| for (int i=0; i<AttachOperation::arg_count_max; i++) { |
| char* arg = args.next(); |
| if (arg == NULL) { |
| op->set_arg(i, NULL); |
| } else { |
| if (strlen(arg) > AttachOperation::arg_length_max) { |
| delete op; |
| return NULL; |
| } |
| op->set_arg(i, arg); |
| } |
| } |
| |
| // return operation |
| *err = 0; |
| return op; |
| } |
| |
| // create special operation to indicate all clients have detached |
| static SolarisAttachOperation* create_detachall_operation() { |
| return new SolarisAttachOperation(AttachOperation::detachall_operation_name()); |
| } |
| |
| // This is door function which the client executes via a door_call. |
| extern "C" { |
| static void enqueue_proc(void* cookie, char* argp, size_t arg_size, |
| door_desc_t* dt, uint_t n_desc) |
| { |
| int return_fd = -1; |
| SolarisAttachOperation* op = NULL; |
| |
| // no listener |
| jint res = 0; |
| if (!AttachListener::is_initialized()) { |
| // how did we get here? |
| debug_only(warning("door_call when not enabled")); |
| res = (jint)SolarisAttachListener::ATTACH_ERROR_INTERNAL; |
| } |
| |
| // check client credentials |
| if (res == 0) { |
| if (check_credentials() != 0) { |
| res = (jint)SolarisAttachListener::ATTACH_ERROR_DENIED; |
| } |
| } |
| |
| // if we are stopped at ShowMessageBoxOnError then maybe we can |
| // load a diagnostic library |
| if (res == 0 && VMError::is_error_reported()) { |
| if (ShowMessageBoxOnError) { |
| // TBD - support loading of diagnostic library here |
| } |
| |
| // can't enqueue operation after fatal error |
| res = (jint)SolarisAttachListener::ATTACH_ERROR_RESOURCE; |
| } |
| |
| // create the operation |
| if (res == 0) { |
| int err; |
| op = create_operation(argp, arg_size, &err); |
| res = (op == NULL) ? (jint)err : 0; |
| } |
| |
| // create a pair of connected sockets. Store the file descriptor |
| // for one end in the operation and enqueue the operation. The |
| // file descriptor for the other end wil be returned to the client. |
| if (res == 0) { |
| int s[2]; |
| if (socketpair(PF_UNIX, SOCK_STREAM, 0, s) < 0) { |
| delete op; |
| res = (jint)SolarisAttachListener::ATTACH_ERROR_RESOURCE; |
| } else { |
| op->set_socket(s[0]); |
| return_fd = s[1]; |
| SolarisAttachListener::enqueue(op); |
| } |
| } |
| |
| // Return 0 (success) + file descriptor, or non-0 (error) |
| if (res == 0) { |
| door_desc_t desc; |
| // DOOR_RELEASE flag makes sure fd is closed after passing it to |
| // the client. See door_return(3DOOR) man page. |
| desc.d_attributes = DOOR_DESCRIPTOR | DOOR_RELEASE; |
| desc.d_data.d_desc.d_descriptor = return_fd; |
| door_return((char*)&res, sizeof(res), &desc, 1); |
| } else { |
| door_return((char*)&res, sizeof(res), NULL, 0); |
| } |
| } |
| } |
| |
| // atexit hook to detach the door and remove the file |
| extern "C" { |
| static void listener_cleanup() { |
| static int cleanup_done; |
| if (!cleanup_done) { |
| cleanup_done = 1; |
| int dd = SolarisAttachListener::door_descriptor(); |
| if (dd >= 0) { |
| ::close(dd); |
| } |
| if (SolarisAttachListener::has_door_path()) { |
| char* path = SolarisAttachListener::door_path(); |
| ::fdetach(path); |
| ::unlink(path); |
| } |
| } |
| } |
| } |
| |
| // Create the door |
| int SolarisAttachListener::create_door() { |
| char door_path[PATH_MAX+1]; |
| char initial_path[PATH_MAX+1]; |
| int fd, res; |
| |
| // register exit function |
| ::atexit(listener_cleanup); |
| |
| // create the door descriptor |
| int dd = ::door_create(enqueue_proc, NULL, 0); |
| if (dd < 0) { |
| return -1; |
| } |
| |
| // create initial file to attach door descriptor |
| snprintf(door_path, sizeof(door_path), "%s/.java_pid%d", |
| os::get_temp_directory(), os::current_process_id()); |
| snprintf(initial_path, sizeof(initial_path), "%s.tmp", door_path); |
| RESTARTABLE(::creat(initial_path, S_IRUSR | S_IWUSR), fd); |
| if (fd == -1) { |
| log_debug(attach)("attempt to create door file %s failed (%d)", initial_path, errno); |
| ::door_revoke(dd); |
| return -1; |
| } |
| assert(fd >= 0, "bad file descriptor"); |
| ::close(fd); |
| |
| // attach the door descriptor to the file |
| if ((res = ::fattach(dd, initial_path)) == -1) { |
| // if busy then detach and try again |
| if (errno == EBUSY) { |
| ::fdetach(initial_path); |
| res = ::fattach(dd, initial_path); |
| } |
| if (res == -1) { |
| log_debug(attach)("unable to create door - fattach failed (%d)", errno); |
| ::door_revoke(dd); |
| dd = -1; |
| } |
| } |
| |
| // rename file so that clients can attach |
| if (dd >= 0) { |
| if (::rename(initial_path, door_path) == -1) { |
| ::close(dd); |
| ::fdetach(initial_path); |
| log_debug(attach)("unable to create door - rename %s to %s failed (%d)", errno); |
| dd = -1; |
| } |
| } |
| if (dd >= 0) { |
| set_door_descriptor(dd); |
| set_door_path(door_path); |
| log_trace(attach)("door file %s created succesfully", door_path); |
| } else { |
| // unable to create door, attach it to file, or rename file into place |
| ::unlink(initial_path); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| // Initialization - create the door, locks, and other initialization |
| int SolarisAttachListener::init() { |
| if (create_door()) { |
| return -1; |
| } |
| |
| int status = os::Solaris::mutex_init(&_mutex); |
| assert_status(status==0, status, "mutex_init"); |
| |
| status = ::sema_init(&_wakeup, 0, NULL, NULL); |
| assert_status(status==0, status, "sema_init"); |
| |
| set_head(NULL); |
| set_tail(NULL); |
| |
| return 0; |
| } |
| |
| // Dequeue an operation |
| SolarisAttachOperation* SolarisAttachListener::dequeue() { |
| for (;;) { |
| int res; |
| |
| // wait for somebody to enqueue something |
| while ((res = ::sema_wait(wakeup())) == EINTR) |
| ; |
| if (res) { |
| warning("sema_wait failed: %s", os::strerror(res)); |
| return NULL; |
| } |
| |
| // lock the list |
| res = os::Solaris::mutex_lock(mutex()); |
| assert(res == 0, "mutex_lock failed"); |
| |
| // remove the head of the list |
| SolarisAttachOperation* op = head(); |
| if (op != NULL) { |
| set_head(op->next()); |
| if (head() == NULL) { |
| set_tail(NULL); |
| } |
| } |
| |
| // unlock |
| os::Solaris::mutex_unlock(mutex()); |
| |
| // if we got an operation when return it. |
| if (op != NULL) { |
| return op; |
| } |
| } |
| } |
| |
| // Enqueue an operation |
| void SolarisAttachListener::enqueue(SolarisAttachOperation* op) { |
| // lock list |
| int res = os::Solaris::mutex_lock(mutex()); |
| assert(res == 0, "mutex_lock failed"); |
| |
| // enqueue at tail |
| op->set_next(NULL); |
| if (head() == NULL) { |
| set_head(op); |
| } else { |
| tail()->set_next(op); |
| } |
| set_tail(op); |
| |
| // wakeup the attach listener |
| RESTARTABLE(::sema_post(wakeup()), res); |
| assert(res == 0, "sema_post failed"); |
| |
| // unlock |
| os::Solaris::mutex_unlock(mutex()); |
| } |
| |
| |
| // support function - writes the (entire) buffer to a socket |
| static int write_fully(int s, char* buf, int len) { |
| do { |
| int n = ::write(s, buf, len); |
| if (n == -1) { |
| if (errno != EINTR) return -1; |
| } else { |
| buf += n; |
| len -= n; |
| } |
| } |
| while (len > 0); |
| return 0; |
| } |
| |
| // Complete an operation by sending the operation result and any result |
| // output to the client. At this time the socket is in blocking mode so |
| // potentially we can block if there is a lot of data and the client is |
| // non-responsive. For most operations this is a non-issue because the |
| // default send buffer is sufficient to buffer everything. In the future |
| // if there are operations that involves a very big reply then it the |
| // socket could be made non-blocking and a timeout could be used. |
| |
| void SolarisAttachOperation::complete(jint res, bufferedStream* st) { |
| if (this->socket() >= 0) { |
| JavaThread* thread = JavaThread::current(); |
| ThreadBlockInVM tbivm(thread); |
| |
| thread->set_suspend_equivalent(); |
| // cleared by handle_special_suspend_equivalent_condition() or |
| // java_suspend_self() via check_and_wait_while_suspended() |
| |
| // write operation result |
| char msg[32]; |
| sprintf(msg, "%d\n", res); |
| int rc = write_fully(this->socket(), msg, strlen(msg)); |
| |
| // write any result data |
| if (rc == 0) { |
| write_fully(this->socket(), (char*) st->base(), st->size()); |
| ::shutdown(this->socket(), 2); |
| } |
| |
| // close socket and we're done |
| ::close(this->socket()); |
| |
| // were we externally suspended while we were waiting? |
| thread->check_and_wait_while_suspended(); |
| } |
| delete this; |
| } |
| |
| |
| // AttachListener functions |
| |
| AttachOperation* AttachListener::dequeue() { |
| JavaThread* thread = JavaThread::current(); |
| ThreadBlockInVM tbivm(thread); |
| |
| thread->set_suspend_equivalent(); |
| // cleared by handle_special_suspend_equivalent_condition() or |
| // java_suspend_self() via check_and_wait_while_suspended() |
| |
| AttachOperation* op = SolarisAttachListener::dequeue(); |
| |
| // were we externally suspended while we were waiting? |
| thread->check_and_wait_while_suspended(); |
| |
| return op; |
| } |
| |
| |
| // Performs initialization at vm startup |
| // For Solaris we remove any stale .java_pid file which could cause |
| // an attaching process to think we are ready to receive a door_call |
| // before we are properly initialized |
| |
| void AttachListener::vm_start() { |
| char fn[PATH_MAX+1]; |
| struct stat64 st; |
| int ret; |
| |
| int n = snprintf(fn, sizeof(fn), "%s/.java_pid%d", |
| os::get_temp_directory(), os::current_process_id()); |
| assert(n < sizeof(fn), "java_pid file name buffer overflow"); |
| |
| RESTARTABLE(::stat64(fn, &st), ret); |
| if (ret == 0) { |
| ret = ::unlink(fn); |
| if (ret == -1) { |
| log_debug(attach)("Failed to remove stale attach pid file at %s", fn); |
| } |
| } |
| } |
| |
| int AttachListener::pd_init() { |
| JavaThread* thread = JavaThread::current(); |
| ThreadBlockInVM tbivm(thread); |
| |
| thread->set_suspend_equivalent(); |
| // cleared by handle_special_suspend_equivalent_condition() or |
| // java_suspend_self() |
| |
| int ret_code = SolarisAttachListener::init(); |
| |
| // were we externally suspended while we were waiting? |
| thread->check_and_wait_while_suspended(); |
| |
| return ret_code; |
| } |
| |
| // Attach Listener is started lazily except in the case when |
| // +ReduseSignalUsage is used |
| bool AttachListener::init_at_startup() { |
| if (ReduceSignalUsage) { |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| // If the file .attach_pid<pid> exists in the working directory |
| // or /tmp then this is the trigger to start the attach mechanism |
| bool AttachListener::is_init_trigger() { |
| if (init_at_startup() || is_initialized()) { |
| return false; // initialized at startup or already initialized |
| } |
| char fn[PATH_MAX+1]; |
| sprintf(fn, ".attach_pid%d", os::current_process_id()); |
| int ret; |
| struct stat64 st; |
| RESTARTABLE(::stat64(fn, &st), ret); |
| if (ret == -1) { |
| log_trace(attach)("Failed to find attach file: %s, trying alternate", fn); |
| snprintf(fn, sizeof(fn), "%s/.attach_pid%d", |
| os::get_temp_directory(), os::current_process_id()); |
| RESTARTABLE(::stat64(fn, &st), ret); |
| if (ret == -1) { |
| log_debug(attach)("Failed to find attach file: %s", fn); |
| } |
| } |
| if (ret == 0) { |
| // simple check to avoid starting the attach mechanism when |
| // a bogus user creates the file |
| if (st.st_uid == geteuid()) { |
| init(); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // if VM aborts then detach/cleanup |
| void AttachListener::abort() { |
| listener_cleanup(); |
| } |
| |
| void AttachListener::pd_data_dump() { |
| os::signal_notify(SIGQUIT); |
| } |
| |
| static jint enable_dprobes(AttachOperation* op, outputStream* out) { |
| const char* probe = op->arg(0); |
| if (probe == NULL || probe[0] == '\0') { |
| out->print_cr("No probe specified"); |
| return JNI_ERR; |
| } else { |
| char *end; |
| long val = strtol(probe, &end, 10); |
| if (end == probe || val < 0 || val > INT_MAX) { |
| out->print_cr("invalid probe type"); |
| return JNI_ERR; |
| } else { |
| int probe_typess = (int) val; |
| DTrace::enable_dprobes(probe_typess); |
| return JNI_OK; |
| } |
| } |
| } |
| |
| // platform specific operations table |
| static AttachOperationFunctionInfo funcs[] = { |
| { "enabledprobes", enable_dprobes }, |
| { NULL, NULL } |
| }; |
| |
| AttachOperationFunctionInfo* AttachListener::pd_find_operation(const char* name) { |
| int i; |
| for (i = 0; funcs[i].name != NULL; i++) { |
| if (strcmp(funcs[i].name, name) == 0) { |
| return &funcs[i]; |
| } |
| } |
| return NULL; |
| } |
| |
| // Solaris specific global flag set. Currently, we support only |
| // changing ExtendedDTraceProbes flag. |
| jint AttachListener::pd_set_flag(AttachOperation* op, outputStream* out) { |
| const char* name = op->arg(0); |
| assert(name != NULL, "flag name should not be null"); |
| bool flag = true; |
| const char* arg1; |
| if ((arg1 = op->arg(1)) != NULL) { |
| char *end; |
| flag = (strtol(arg1, &end, 10) != 0); |
| if (arg1 == end) { |
| out->print_cr("flag value has to be an integer"); |
| return JNI_ERR; |
| } |
| } |
| |
| if (strcmp(name, "ExtendedDTraceProbes") == 0) { |
| DTrace::set_extended_dprobes(flag); |
| return JNI_OK; |
| } |
| |
| if (strcmp(name, "DTraceMonitorProbes") == 0) { |
| DTrace::set_monitor_dprobes(flag); |
| return JNI_OK; |
| } |
| |
| out->print_cr("flag '%s' cannot be changed", name); |
| return JNI_ERR; |
| } |
| |
| void AttachListener::pd_detachall() { |
| DTrace::detach_all_clients(); |
| } |