1 /*
2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "prims/jvm.h"
26 #include "runtime/frame.inline.hpp"
27 #include "runtime/os.hpp"
28 #include "utilities/vmError.hpp"
29
30 #include <unistd.h>
31 #include <sys/resource.h>
32 #include <sys/utsname.h>
33 #include <pthread.h>
34 #include <signal.h>
35
36
37 // Check core dump limit and report possible place where core can be found
38 void os::check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize) {
39 int n;
40 struct rlimit rlim;
41 bool success;
42
43 n = get_core_path(buffer, bufferSize);
44
45 if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
46 jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (may not exist)", current_process_id());
47 success = true;
48 } else {
49 switch(rlim.rlim_cur) {
50 case RLIM_INFINITY:
51 jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d", current_process_id());
52 success = true;
53 break;
54 case 0:
55 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
56 success = false;
57 break;
58 default:
59 jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", current_process_id(), (unsigned long)(rlim.rlim_cur >> 10));
60 success = true;
61 break;
62 }
63 }
64 VMError::report_coredump_status(buffer, success);
65 }
66
67 address os::get_caller_pc(int n) {
68 #ifdef _NMT_NOINLINE_
69 n ++;
70 #endif
71 frame fr = os::current_frame();
72 while (n > 0 && fr.pc() &&
73 !os::is_first_C_frame(&fr) && fr.sender_pc()) {
74 fr = os::get_sender_for_C_frame(&fr);
75 n --;
76 }
77 if (n == 0) {
78 return fr.pc();
79 } else {
80 return NULL;
81 }
82 }
83
84 int os::get_last_error() {
85 return errno;
86 }
87
88 bool os::is_debugger_attached() {
89 // not implemented
90 return false;
91 }
92
93 void os::wait_for_keypress_at_exit(void) {
94 // don't do anything on posix platforms
95 return;
96 }
97
98 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
99 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
100 // rather than unmapping and remapping the whole chunk to get requested alignment.
101 char* os::reserve_memory_aligned(size_t size, size_t alignment) {
102 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
103 "Alignment must be a multiple of allocation granularity (page size)");
104 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
105
106 size_t extra_size = size + alignment;
107 assert(extra_size >= size, "overflow, size is too large to allow alignment");
108
109 char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
110
111 if (extra_base == NULL) {
112 return NULL;
113 }
114
115 // Do manual alignment
116 char* aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);
117
118 // [ | | ]
119 // ^ extra_base
120 // ^ extra_base + begin_offset == aligned_base
121 // extra_base + begin_offset + size ^
122 // extra_base + extra_size ^
123 // |<>| == begin_offset
124 // end_offset == |<>|
125 size_t begin_offset = aligned_base - extra_base;
126 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
127
128 if (begin_offset > 0) {
129 os::release_memory(extra_base, begin_offset);
130 }
131
132 if (end_offset > 0) {
133 os::release_memory(extra_base + begin_offset + size, end_offset);
134 }
135
136 return aligned_base;
137 }
138
139 void os::Posix::print_load_average(outputStream* st) {
140 st->print("load average:");
141 double loadavg[3];
142 os::loadavg(loadavg, 3);
143 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
144 st->cr();
145 }
146
147 void os::Posix::print_rlimit_info(outputStream* st) {
148 st->print("rlimit:");
149 struct rlimit rlim;
150
151 st->print(" STACK ");
152 getrlimit(RLIMIT_STACK, &rlim);
153 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
154 else st->print("%uk", rlim.rlim_cur >> 10);
155
156 st->print(", CORE ");
157 getrlimit(RLIMIT_CORE, &rlim);
158 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
159 else st->print("%uk", rlim.rlim_cur >> 10);
160
161 //Isn't there on solaris
162 #ifndef TARGET_OS_FAMILY_solaris
163 st->print(", NPROC ");
164 getrlimit(RLIMIT_NPROC, &rlim);
165 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
166 else st->print("%d", rlim.rlim_cur);
167 #endif
168
169 st->print(", NOFILE ");
170 getrlimit(RLIMIT_NOFILE, &rlim);
171 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
172 else st->print("%d", rlim.rlim_cur);
173
174 st->print(", AS ");
175 getrlimit(RLIMIT_AS, &rlim);
176 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
177 else st->print("%uk", rlim.rlim_cur >> 10);
178 st->cr();
179 }
180
181 void os::Posix::print_uname_info(outputStream* st) {
182 // kernel
183 st->print("uname:");
184 struct utsname name;
185 uname(&name);
186 st->print(name.sysname); st->print(" ");
187 st->print(name.release); st->print(" ");
188 st->print(name.version); st->print(" ");
189 st->print(name.machine);
190 st->cr();
191 }
192
193 bool os::has_allocatable_memory_limit(julong* limit) {
194 struct rlimit rlim;
195 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
196 // if there was an error when calling getrlimit, assume that there is no limitation
197 // on virtual memory.
198 bool result;
199 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
200 result = false;
201 } else {
202 *limit = (julong)rlim.rlim_cur;
203 result = true;
204 }
205 #ifdef _LP64
206 return result;
207 #else
208 // arbitrary virtual space limit for 32 bit Unices found by testing. If
209 // getrlimit above returned a limit, bound it with this limit. Otherwise
210 // directly use it.
211 const julong max_virtual_limit = (julong)3800*M;
212 if (result) {
213 *limit = MIN2(*limit, max_virtual_limit);
214 } else {
215 *limit = max_virtual_limit;
216 }
217
218 // bound by actually allocatable memory. The algorithm uses two bounds, an
219 // upper and a lower limit. The upper limit is the current highest amount of
220 // memory that could not be allocated, the lower limit is the current highest
221 // amount of memory that could be allocated.
222 // The algorithm iteratively refines the result by halving the difference
223 // between these limits, updating either the upper limit (if that value could
224 // not be allocated) or the lower limit (if the that value could be allocated)
225 // until the difference between these limits is "small".
226
227 // the minimum amount of memory we care about allocating.
228 const julong min_allocation_size = M;
229
230 julong upper_limit = *limit;
231
232 // first check a few trivial cases
233 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
234 *limit = upper_limit;
235 } else if (!is_allocatable(min_allocation_size)) {
236 // we found that not even min_allocation_size is allocatable. Return it
237 // anyway. There is no point to search for a better value any more.
238 *limit = min_allocation_size;
239 } else {
240 // perform the binary search.
241 julong lower_limit = min_allocation_size;
242 while ((upper_limit - lower_limit) > min_allocation_size) {
243 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
244 temp_limit = align_size_down_(temp_limit, min_allocation_size);
245 if (is_allocatable(temp_limit)) {
246 lower_limit = temp_limit;
247 } else {
248 upper_limit = temp_limit;
249 }
250 }
251 *limit = lower_limit;
252 }
253 return true;
254 #endif
255 }
256
257 const char* os::get_current_directory(char *buf, size_t buflen) {
258 return getcwd(buf, buflen);
259 }
260
261 FILE* os::open(int fd, const char* mode) {
262 return ::fdopen(fd, mode);
263 }
264
265 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
266 // which is used to find statically linked in agents.
267 // Parameters:
268 // sym_name: Symbol in library we are looking for
269 // lib_name: Name of library to look in, NULL for shared libs.
270 // is_absolute_path == true if lib_name is absolute path to agent
271 // such as "/a/b/libL.so"
272 // == false if only the base name of the library is passed in
273 // such as "L"
274 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
275 bool is_absolute_path) {
276 char *agent_entry_name;
277 size_t len;
278 size_t name_len;
279 size_t prefix_len = strlen(JNI_LIB_PREFIX);
280 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
281 const char *start;
282
283 if (lib_name != NULL) {
284 len = name_len = strlen(lib_name);
285 if (is_absolute_path) {
286 // Need to strip path, prefix and suffix
287 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
288 lib_name = ++start;
289 }
290 if (len <= (prefix_len + suffix_len)) {
291 return NULL;
292 }
293 lib_name += prefix_len;
294 name_len = strlen(lib_name) - suffix_len;
295 }
296 }
297 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
298 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
299 if (agent_entry_name == NULL) {
300 return NULL;
301 }
302 strcpy(agent_entry_name, sym_name);
303 if (lib_name != NULL) {
304 strcat(agent_entry_name, "_");
305 strncat(agent_entry_name, lib_name, name_len);
306 }
307 return agent_entry_name;
308 }
309
310 os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
311 assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
312 }
313
314 /*
315 * See the caveats for this class in os_posix.hpp
316 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
317 * method and returns false. If none of the signals are raised, returns true.
318 * The callback is supposed to provide the method that should be protected.
319 */
320 bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
321 sigset_t saved_sig_mask;
322
323 assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
324 assert(!WatcherThread::watcher_thread()->has_crash_protection(),
325 "crash_protection already set?");
326
327 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
328 // since on at least some systems (OS X) siglongjmp will restore the mask
329 // for the process, not the thread
330 pthread_sigmask(0, NULL, &saved_sig_mask);
331 if (sigsetjmp(_jmpbuf, 0) == 0) {
332 // make sure we can see in the signal handler that we have crash protection
333 // installed
334 WatcherThread::watcher_thread()->set_crash_protection(this);
335 cb.call();
336 // and clear the crash protection
337 WatcherThread::watcher_thread()->set_crash_protection(NULL);
338 return true;
339 }
340 // this happens when we siglongjmp() back
341 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
342 WatcherThread::watcher_thread()->set_crash_protection(NULL);
343 return false;
344 }
345
346 void os::WatcherThreadCrashProtection::restore() {
347 assert(WatcherThread::watcher_thread()->has_crash_protection(),
348 "must have crash protection");
349
350 siglongjmp(_jmpbuf, 1);
351 }
352
353 void os::WatcherThreadCrashProtection::check_crash_protection(int sig,
354 Thread* thread) {
355
356 if (thread != NULL &&
357 thread->is_Watcher_thread() &&
358 WatcherThread::watcher_thread()->has_crash_protection()) {
359
360 if (sig == SIGSEGV || sig == SIGBUS) {
361 WatcherThread::watcher_thread()->crash_protection()->restore();
362 }
363 }
364 }