1 /*
2 * Copyright (c) 2019, 2020, 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 #if defined(LINUX) || defined(__APPLE__)
26 #include <unistd.h>
27 #include <fcntl.h>
28 #include <string.h>
29 #include <stdlib.h>
30 #include <stddef.h>
31 #ifdef LINUX
32 #include <elf.h>
33 #include <link.h>
34 #include "proc_service.h"
35 #include "salibelf.h"
36 #endif
37 #include "libproc_impl.h"
38 #include "cds.h"
39
40 #ifdef __APPLE__
41 #include "sun_jvm_hotspot_debugger_amd64_AMD64ThreadContext.h"
42 #endif
43
44 #ifdef LINUX
45 // I have no idea why this function is called ps_pread() on macos but ps_pdread on linux.
46 #define ps_pread ps_pdread
47 #endif
48
49 // Common code shared between linux/native/libsaproc/ps_core.c and macosx/native/libsaproc/ps_core.c
50
51 //----------------------------------------------------------------------
52 // ps_prochandle cleanup helper functions
53
54 // close all file descriptors
55 static void close_files(struct ps_prochandle* ph) {
56 lib_info* lib = NULL;
57
58 // close core file descriptor
59 if (ph->core->core_fd >= 0)
60 close(ph->core->core_fd);
61
62 // close exec file descriptor
63 if (ph->core->exec_fd >= 0)
64 close(ph->core->exec_fd);
65
66 // close interp file descriptor
67 if (ph->core->interp_fd >= 0)
68 close(ph->core->interp_fd);
69
70 // close class share archive file
71 if (ph->core->classes_jsa_fd >= 0)
72 close(ph->core->classes_jsa_fd);
73
74 // close all library file descriptors
75 lib = ph->libs;
76 while (lib) {
77 int fd = lib->fd;
78 if (fd >= 0 && fd != ph->core->exec_fd) {
79 close(fd);
80 }
81 lib = lib->next;
82 }
83 }
84
85 // clean all map_info stuff
86 static void destroy_map_info(struct ps_prochandle* ph) {
87 map_info* map = ph->core->maps;
88 while (map) {
89 map_info* next = map->next;
90 free(map);
91 map = next;
92 }
93
94 if (ph->core->map_array) {
95 free(ph->core->map_array);
96 }
97
98 // Part of the class sharing workaround
99 map = ph->core->class_share_maps;
100 while (map) {
101 map_info* next = map->next;
102 free(map);
103 map = next;
104 }
105 }
106
107 // ps_prochandle operations
108 void core_release(struct ps_prochandle* ph) {
109 if (ph->core) {
110 close_files(ph);
111 destroy_map_info(ph);
112 free(ph->core);
113 }
114 }
115
116 static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
117 map_info* map;
118 if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
119 print_debug("can't allocate memory for map_info\n");
120 return NULL;
121 }
122
123 // initialize map
124 map->fd = fd;
125 map->offset = offset;
126 map->vaddr = vaddr;
127 map->memsz = memsz;
128 return map;
129 }
130
131 // add map info with given fd, offset, vaddr and memsz
132 map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
133 uintptr_t vaddr, size_t memsz) {
134 map_info* map;
135 if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
136 return NULL;
137 }
138
139 // add this to map list
140 map->next = ph->core->maps;
141 ph->core->maps = map;
142 ph->core->num_maps++;
143
144 return map;
145 }
146
147 // Part of the class sharing workaround
148 static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
149 uintptr_t vaddr, size_t memsz) {
150 map_info* map;
151 if ((map = allocate_init_map(ph->core->classes_jsa_fd,
152 offset, vaddr, memsz)) == NULL) {
153 return NULL;
154 }
155
156 map->next = ph->core->class_share_maps;
157 ph->core->class_share_maps = map;
158 return map;
159 }
160
161 // Return the map_info for the given virtual address. We keep a sorted
162 // array of pointers in ph->map_array, so we can binary search.
163 map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr) {
164 int mid, lo = 0, hi = ph->core->num_maps - 1;
165 map_info *mp;
166
167 while (hi - lo > 1) {
168 mid = (lo + hi) / 2;
169 if (addr >= ph->core->map_array[mid]->vaddr) {
170 lo = mid;
171 } else {
172 hi = mid;
173 }
174 }
175
176 if (addr < ph->core->map_array[hi]->vaddr) {
177 mp = ph->core->map_array[lo];
178 } else {
179 mp = ph->core->map_array[hi];
180 }
181
182 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
183 return (mp);
184 }
185
186
187 // Part of the class sharing workaround
188 // Unfortunately, we have no way of detecting -Xshare state.
189 // Check out the share maps atlast, if we don't find anywhere.
190 // This is done this way so to avoid reading share pages
191 // ahead of other normal maps. For eg. with -Xshare:off we don't
192 // want to prefer class sharing data to data from core.
193 mp = ph->core->class_share_maps;
194 if (mp) {
195 print_debug("can't locate map_info at 0x%lx, trying class share maps\n", addr);
196 }
197 while (mp) {
198 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
199 print_debug("located map_info at 0x%lx from class share maps\n", addr);
200 return (mp);
201 }
202 mp = mp->next;
203 }
204
205 print_debug("can't locate map_info at 0x%lx\n", addr);
206 return (NULL);
207 }
208
209 //---------------------------------------------------------------
210 // Part of the class sharing workaround:
211 //
212 // With class sharing, pages are mapped from classes.jsa file.
213 // The read-only class sharing pages are mapped as MAP_SHARED,
214 // PROT_READ pages. These pages are not dumped into core dump.
215 // With this workaround, these pages are read from classes.jsa.
216
217 static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
218 jboolean i;
219 if (ps_pread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
220 *pvalue = i;
221 return true;
222 } else {
223 return false;
224 }
225 }
226
227 static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
228 uintptr_t uip;
229 if (ps_pread(ph, (psaddr_t) addr, (char *)&uip, sizeof(uip)) == PS_OK) {
230 *pvalue = uip;
231 return true;
232 } else {
233 return false;
234 }
235 }
236
237 // used to read strings from debuggee
238 bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
239 size_t i = 0;
240 char c = ' ';
241
242 while (c != '\0') {
243 if (ps_pread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK) {
244 return false;
245 }
246 if (i < size - 1) {
247 buf[i] = c;
248 } else {
249 // smaller buffer
250 return false;
251 }
252 i++; addr++;
253 }
254 buf[i] = '\0';
255 return true;
256 }
257
258 #ifdef LINUX
259 // mangled name of Arguments::SharedArchivePath
260 #define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
261 #define USE_SHARED_SPACES_SYM "UseSharedSpaces"
262 #define SHARED_BASE_ADDRESS_SYM "SharedBaseAddress"
263 #define LIBJVM_NAME "/libjvm.so"
264 #endif
265
266 #ifdef __APPLE__
267 // mangled name of Arguments::SharedArchivePath
268 #define SHARED_ARCHIVE_PATH_SYM "__ZN9Arguments17SharedArchivePathE"
269 #define USE_SHARED_SPACES_SYM "_UseSharedSpaces"
270 #define SHARED_BASE_ADDRESS_SYM "_SharedBaseAddress"
271 #define LIBJVM_NAME "/libjvm.dylib"
272 #endif
273
274 bool init_classsharing_workaround(struct ps_prochandle* ph) {
275 lib_info* lib = ph->libs;
276 while (lib != NULL) {
277 // we are iterating over shared objects from the core dump. look for
278 // libjvm.so.
279 const char *jvm_name = 0;
280 if ((jvm_name = strstr(lib->name, LIBJVM_NAME)) != 0) {
281 char classes_jsa[PATH_MAX];
282 CDSFileMapHeaderBase header;
283 int fd = -1;
284 uintptr_t useSharedSpacesAddr = 0;
285 uintptr_t sharedBaseAddressAddr = 0, sharedBaseAddress = 0;
286 uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
287 jboolean useSharedSpaces = 0;
288 int m;
289 size_t n;
290
291 memset(classes_jsa, 0, sizeof(classes_jsa));
292 jvm_name = lib->name;
293 useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
294 if (useSharedSpacesAddr == 0) {
295 print_debug("can't lookup 'UseSharedSpaces' flag\n");
296 return false;
297 }
298
299 // Hotspot vm types are not exported to build this library. So
300 // using equivalent type jboolean to read the value of
301 // UseSharedSpaces which is same as hotspot type "bool".
302 if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
303 print_debug("can't read the value of 'UseSharedSpaces' flag\n");
304 return false;
305 }
306
307 if ((int)useSharedSpaces == 0) {
308 print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
309 return true;
310 }
311
312 sharedBaseAddressAddr = lookup_symbol(ph, jvm_name, SHARED_BASE_ADDRESS_SYM);
313 if (sharedBaseAddressAddr == 0) {
314 print_debug("can't lookup 'SharedBaseAddress' flag\n");
315 return false;
316 }
317
318 if (read_pointer(ph, sharedBaseAddressAddr, &sharedBaseAddress) != true) {
319 print_debug("can't read the value of 'SharedBaseAddress' flag\n");
320 return false;
321 }
322
323 sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
324 if (sharedArchivePathAddrAddr == 0) {
325 print_debug("can't lookup shared archive path symbol\n");
326 return false;
327 }
328
329 if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
330 print_debug("can't read shared archive path pointer\n");
331 return false;
332 }
333
334 if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
335 print_debug("can't read shared archive path value\n");
336 return false;
337 }
338
339 print_debug("looking for %s\n", classes_jsa);
340 // open the class sharing archive file
341 fd = pathmap_open(classes_jsa);
342 if (fd < 0) {
343 print_debug("can't open %s!\n", classes_jsa);
344 ph->core->classes_jsa_fd = -1;
345 return false;
346 } else {
347 print_debug("opened %s\n", classes_jsa);
348 }
349
350 // read CDSFileMapHeaderBase from the file
351 memset(&header, 0, sizeof(CDSFileMapHeaderBase));
352 if ((n = read(fd, &header, sizeof(CDSFileMapHeaderBase)))
353 != sizeof(CDSFileMapHeaderBase)) {
354 print_debug("can't read shared archive file map header from %s\n", classes_jsa);
355 close(fd);
356 return false;
357 }
358
359 // check file magic
360 if (header._magic != CDS_ARCHIVE_MAGIC) {
361 print_debug("%s has bad shared archive file magic number 0x%x, expecting 0x%x\n",
362 classes_jsa, header._magic, CDS_ARCHIVE_MAGIC);
363 close(fd);
364 return false;
365 }
366
367 // check version
368 if (header._version != CURRENT_CDS_ARCHIVE_VERSION) {
369 print_debug("%s has wrong shared archive file version %d, expecting %d\n",
370 classes_jsa, header._version, CURRENT_CDS_ARCHIVE_VERSION);
371 close(fd);
372 return false;
373 }
374
375 ph->core->classes_jsa_fd = fd;
376 // add read-only maps from classes.jsa to the list of maps
377 for (m = 0; m < NUM_CDS_REGIONS; m++) {
378 if (header._space[m]._read_only &&
379 !header._space[m]._is_heap_region &&
380 !header._space[m]._is_bitmap_region) {
381 // With *some* linux versions, the core file doesn't include read-only mmap'ed
382 // files regions, so let's add them here. This is harmless if the core file also
383 // include these regions.
384 uintptr_t base = sharedBaseAddress + (uintptr_t) header._space[m]._mapping_offset;
385 size_t size = header._space[m]._used;
386 // no need to worry about the fractional pages at-the-end.
387 // possible fractional pages are handled by core_read_data.
388 add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
389 base, size);
390 print_debug("added a share archive map [%d] at 0x%lx (size 0x%lx bytes)\n", m, base, size);
391 }
392 }
393 return true;
394 }
395 lib = lib->next;
396 }
397 return true;
398 }
399
400 #endif // defined(LINUX) || defined(__APPLE__)