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