1 /*
2 * Copyright (c) 2003, 2018, 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 <jni.h>
26 #include <unistd.h>
27 #include <fcntl.h>
28 #include <string.h>
29 #include <stdlib.h>
30 #include <stddef.h>
31 #include <elf.h>
32 #include <link.h>
33 #include "libproc_impl.h"
34 #include "salibelf.h"
35
36 // This file has the libproc implementation to read core files.
37 // For live processes, refer to ps_proc.c. Portions of this is adapted
38 // /modelled after Solaris libproc.so (in particular Pcore.c)
39
40 //----------------------------------------------------------------------
41 // ps_prochandle cleanup helper functions
42
43 // close all file descriptors
44 static void close_files(struct ps_prochandle* ph) {
45 lib_info* lib = NULL;
46
47 // close core file descriptor
48 if (ph->core->core_fd >= 0)
49 close(ph->core->core_fd);
50
51 // close exec file descriptor
52 if (ph->core->exec_fd >= 0)
53 close(ph->core->exec_fd);
54
55 // close interp file descriptor
56 if (ph->core->interp_fd >= 0)
57 close(ph->core->interp_fd);
58
59 // close class share archive file
60 if (ph->core->classes_jsa_fd >= 0)
61 close(ph->core->classes_jsa_fd);
62
63 // close all library file descriptors
64 lib = ph->libs;
65 while (lib) {
66 int fd = lib->fd;
67 if (fd >= 0 && fd != ph->core->exec_fd) {
68 close(fd);
69 }
70 lib = lib->next;
71 }
72 }
73
74 // clean all map_info stuff
75 static void destroy_map_info(struct ps_prochandle* ph) {
76 map_info* map = ph->core->maps;
77 while (map) {
78 map_info* next = map->next;
79 free(map);
80 map = next;
81 }
82
83 if (ph->core->map_array) {
84 free(ph->core->map_array);
85 }
86
87 // Part of the class sharing workaround
88 map = ph->core->class_share_maps;
89 while (map) {
90 map_info* next = map->next;
91 free(map);
92 map = next;
93 }
94 }
95
96 // ps_prochandle operations
97 static void core_release(struct ps_prochandle* ph) {
98 if (ph->core) {
99 close_files(ph);
100 destroy_map_info(ph);
101 free(ph->core);
102 }
103 }
104
105 static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
106 map_info* map;
107 if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
108 print_debug("can't allocate memory for map_info\n");
109 return NULL;
110 }
111
112 // initialize map
113 map->fd = fd;
114 map->offset = offset;
115 map->vaddr = vaddr;
116 map->memsz = memsz;
117 return map;
118 }
119
120 // add map info with given fd, offset, vaddr and memsz
121 static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
122 uintptr_t vaddr, size_t memsz) {
123 map_info* map;
124 if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
125 return NULL;
126 }
127
128 // add this to map list
129 map->next = ph->core->maps;
130 ph->core->maps = map;
131 ph->core->num_maps++;
132
133 return map;
134 }
135
136 // Part of the class sharing workaround
137 static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
138 uintptr_t vaddr, size_t memsz) {
139 map_info* map;
140 if ((map = allocate_init_map(ph->core->classes_jsa_fd,
141 offset, vaddr, memsz)) == NULL) {
142 return NULL;
143 }
144
145 map->next = ph->core->class_share_maps;
146 ph->core->class_share_maps = map;
147 return map;
148 }
149
150 // Return the map_info for the given virtual address. We keep a sorted
151 // array of pointers in ph->map_array, so we can binary search.
152 static map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr) {
153 int mid, lo = 0, hi = ph->core->num_maps - 1;
154 map_info *mp;
155
156 while (hi - lo > 1) {
157 mid = (lo + hi) / 2;
158 if (addr >= ph->core->map_array[mid]->vaddr) {
159 lo = mid;
160 } else {
161 hi = mid;
162 }
163 }
164
165 if (addr < ph->core->map_array[hi]->vaddr) {
166 mp = ph->core->map_array[lo];
167 } else {
168 mp = ph->core->map_array[hi];
169 }
170
171 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
172 return (mp);
173 }
174
175
176 // Part of the class sharing workaround
177 // Unfortunately, we have no way of detecting -Xshare state.
178 // Check out the share maps atlast, if we don't find anywhere.
179 // This is done this way so to avoid reading share pages
180 // ahead of other normal maps. For eg. with -Xshare:off we don't
181 // want to prefer class sharing data to data from core.
182 mp = ph->core->class_share_maps;
183 if (mp) {
184 print_debug("can't locate map_info at 0x%lx, trying class share maps\n", addr);
185 }
186 while (mp) {
187 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
188 print_debug("located map_info at 0x%lx from class share maps\n", addr);
189 return (mp);
190 }
191 mp = mp->next;
192 }
193
194 print_debug("can't locate map_info at 0x%lx\n", addr);
195 return (NULL);
196 }
197
198 //---------------------------------------------------------------
199 // Part of the class sharing workaround:
200 //
201 // With class sharing, pages are mapped from classes.jsa file.
202 // The read-only class sharing pages are mapped as MAP_SHARED,
203 // PROT_READ pages. These pages are not dumped into core dump.
204 // With this workaround, these pages are read from classes.jsa.
205
206 // FIXME: !HACK ALERT!
207 // The format of sharing achive file header is needed to read shared heap
208 // file mappings. For now, I am hard coding portion of FileMapHeader here.
209 // Refer to filemap.hpp.
210
211 // FileMapHeader describes the shared space data in the file to be
212 // mapped. This structure gets written to a file. It is not a class,
213 // so that the compilers don't add any compiler-private data to it.
214
215 #define NUM_SHARED_MAPS 9
216
217 // Refer to FileMapInfo::_current_version in filemap.hpp
218 #define CURRENT_ARCHIVE_VERSION 3
219
220 typedef unsigned char* address;
221 typedef uintptr_t uintx;
222 typedef intptr_t intx;
223
224 struct FileMapHeader {
225 int _magic; // identify file type.
226 int _crc; // header crc checksum.
227 int _version; // (from enum, above.)
228 size_t _alignment; // how shared archive should be aligned
229 int _obj_alignment; // value of ObjectAlignmentInBytes
230 address _narrow_oop_base; // compressed oop encoding base
231 int _narrow_oop_shift; // compressed oop encoding shift
232 bool _compact_strings; // value of CompactStrings
233 uintx _max_heap_size; // java max heap size during dumping
234 int _narrow_oop_mode; // compressed oop encoding mode
235 int _narrow_klass_shift; // save narrow klass base and shift
236 address _narrow_klass_base;
237 char* _misc_data_patching_start;
238 char* _read_only_tables_start;
239 address _cds_i2i_entry_code_buffers;
240 size_t _cds_i2i_entry_code_buffers_size;
241 size_t _core_spaces_size; // number of bytes allocated by the core spaces
242 // (mc, md, ro, rw and od).
243
244
245 struct space_info {
246 int _crc; // crc checksum of the current space
247 size_t _file_offset; // sizeof(this) rounded to vm page size
248 union {
249 char* _base; // copy-on-write base address
250 intx _offset; // offset from the compressed oop encoding base, only used
251 // by archive heap space
252 } _addr;
253 size_t _used; // for setting space top on read
254 // 4991491 NOTICE These are C++ bool's in filemap.hpp and must match up with
255 // the C type matching the C++ bool type on any given platform.
256 // We assume the corresponding C type is char but licensees
257 // may need to adjust the type of these fields.
258 char _read_only; // read only space?
259 char _allow_exec; // executable code in space?
260 } _space[NUM_SHARED_MAPS];
261
262 // Ignore the rest of the FileMapHeader. We don't need those fields here.
263 };
264
265 static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
266 jboolean i;
267 if (ps_pdread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
268 *pvalue = i;
269 return true;
270 } else {
271 return false;
272 }
273 }
274
275 static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
276 uintptr_t uip;
277 if (ps_pdread(ph, (psaddr_t) addr, (char *)&uip, sizeof(uip)) == PS_OK) {
278 *pvalue = uip;
279 return true;
280 } else {
281 return false;
282 }
283 }
284
285 // used to read strings from debuggee
286 static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
287 size_t i = 0;
288 char c = ' ';
289
290 while (c != '\0') {
291 if (ps_pdread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK) {
292 return false;
293 }
294 if (i < size - 1) {
295 buf[i] = c;
296 } else {
297 // smaller buffer
298 return false;
299 }
300 i++; addr++;
301 }
302
303 buf[i] = '\0';
304 return true;
305 }
306
307 #define USE_SHARED_SPACES_SYM "UseSharedSpaces"
308 // mangled name of Arguments::SharedArchivePath
309 #define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
310 #define LIBJVM_NAME "/libjvm.so"
311
312 static bool init_classsharing_workaround(struct ps_prochandle* ph) {
313 lib_info* lib = ph->libs;
314 while (lib != NULL) {
315 // we are iterating over shared objects from the core dump. look for
316 // libjvm.so.
317 const char *jvm_name = 0;
318 if ((jvm_name = strstr(lib->name, LIBJVM_NAME)) != 0) {
319 char classes_jsa[PATH_MAX];
320 struct FileMapHeader header;
321 int fd = -1;
322 int m = 0;
323 size_t n = 0;
324 uintptr_t base = 0, useSharedSpacesAddr = 0;
325 uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
326 jboolean useSharedSpaces = 0;
327 map_info* mi = 0;
328
329 memset(classes_jsa, 0, sizeof(classes_jsa));
330 jvm_name = lib->name;
331 useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
332 if (useSharedSpacesAddr == 0) {
333 print_debug("can't lookup 'UseSharedSpaces' flag\n");
334 return false;
335 }
336
337 // Hotspot vm types are not exported to build this library. So
338 // using equivalent type jboolean to read the value of
339 // UseSharedSpaces which is same as hotspot type "bool".
340 if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
341 print_debug("can't read the value of 'UseSharedSpaces' flag\n");
342 return false;
343 }
344
345 if ((int)useSharedSpaces == 0) {
346 print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
347 return true;
348 }
349
350 sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
351 if (sharedArchivePathAddrAddr == 0) {
352 print_debug("can't lookup shared archive path symbol\n");
353 return false;
354 }
355
356 if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
357 print_debug("can't read shared archive path pointer\n");
358 return false;
359 }
360
361 if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
362 print_debug("can't read shared archive path value\n");
363 return false;
364 }
365
366 print_debug("looking for %s\n", classes_jsa);
367 // open the class sharing archive file
368 fd = pathmap_open(classes_jsa);
369 if (fd < 0) {
370 print_debug("can't open %s!\n", classes_jsa);
371 ph->core->classes_jsa_fd = -1;
372 return false;
373 } else {
374 print_debug("opened %s\n", classes_jsa);
375 }
376
377 // read FileMapHeader from the file
378 memset(&header, 0, sizeof(struct FileMapHeader));
379 if ((n = read(fd, &header, sizeof(struct FileMapHeader)))
380 != sizeof(struct FileMapHeader)) {
381 print_debug("can't read shared archive file map header from %s\n", classes_jsa);
382 close(fd);
383 return false;
384 }
385
386 // check file magic
387 if (header._magic != 0xf00baba2) {
388 print_debug("%s has bad shared archive file magic number 0x%x, expecing 0xf00baba2\n",
389 classes_jsa, header._magic);
390 close(fd);
391 return false;
392 }
393
394 // check version
395 if (header._version != CURRENT_ARCHIVE_VERSION) {
396 print_debug("%s has wrong shared archive file version %d, expecting %d\n",
397 classes_jsa, header._version, CURRENT_ARCHIVE_VERSION);
398 close(fd);
399 return false;
400 }
401
402 ph->core->classes_jsa_fd = fd;
403 // add read-only maps from classes.jsa to the list of maps
404 for (m = 0; m < NUM_SHARED_MAPS; m++) {
405 if (header._space[m]._read_only) {
406 base = (uintptr_t) header._space[m]._addr._base;
407 // no need to worry about the fractional pages at-the-end.
408 // possible fractional pages are handled by core_read_data.
409 add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
410 base, (size_t) header._space[m]._used);
411 print_debug("added a share archive map at 0x%lx\n", base);
412 }
413 }
414 return true;
415 }
416 lib = lib->next;
417 }
418 return true;
419 }
420
421
422 //---------------------------------------------------------------------------
423 // functions to handle map_info
424
425 // Order mappings based on virtual address. We use this function as the
426 // callback for sorting the array of map_info pointers.
427 static int core_cmp_mapping(const void *lhsp, const void *rhsp)
428 {
429 const map_info *lhs = *((const map_info **)lhsp);
430 const map_info *rhs = *((const map_info **)rhsp);
431
432 if (lhs->vaddr == rhs->vaddr) {
433 return (0);
434 }
435
436 return (lhs->vaddr < rhs->vaddr ? -1 : 1);
437 }
438
439 // we sort map_info by starting virtual address so that we can do
440 // binary search to read from an address.
441 static bool sort_map_array(struct ps_prochandle* ph) {
442 size_t num_maps = ph->core->num_maps;
443 map_info* map = ph->core->maps;
444 int i = 0;
445
446 // allocate map_array
447 map_info** array;
448 if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) {
449 print_debug("can't allocate memory for map array\n");
450 return false;
451 }
452
453 // add maps to array
454 while (map) {
455 array[i] = map;
456 i++;
457 map = map->next;
458 }
459
460 // sort is called twice. If this is second time, clear map array
461 if (ph->core->map_array) {
462 free(ph->core->map_array);
463 }
464
465 ph->core->map_array = array;
466 // sort the map_info array by base virtual address.
467 qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*),
468 core_cmp_mapping);
469
470 // print map
471 if (is_debug()) {
472 int j = 0;
473 print_debug("---- sorted virtual address map ----\n");
474 for (j = 0; j < ph->core->num_maps; j++) {
475 print_debug("base = 0x%lx\tsize = %zu\n", ph->core->map_array[j]->vaddr,
476 ph->core->map_array[j]->memsz);
477 }
478 }
479
480 return true;
481 }
482
483 #ifndef MIN
484 #define MIN(x, y) (((x) < (y))? (x): (y))
485 #endif
486
487 static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
488 ssize_t resid = size;
489 int page_size=sysconf(_SC_PAGE_SIZE);
490 while (resid != 0) {
491 map_info *mp = core_lookup(ph, addr);
492 uintptr_t mapoff;
493 ssize_t len, rem;
494 off_t off;
495 int fd;
496
497 if (mp == NULL) {
498 break; /* No mapping for this address */
499 }
500
501 fd = mp->fd;
502 mapoff = addr - mp->vaddr;
503 len = MIN(resid, mp->memsz - mapoff);
504 off = mp->offset + mapoff;
505
506 if ((len = pread(fd, buf, len, off)) <= 0) {
507 break;
508 }
509
510 resid -= len;
511 addr += len;
512 buf = (char *)buf + len;
513
514 // mappings always start at page boundary. But, may end in fractional
515 // page. fill zeros for possible fractional page at the end of a mapping.
516 rem = mp->memsz % page_size;
517 if (rem > 0) {
518 rem = page_size - rem;
519 len = MIN(resid, rem);
520 resid -= len;
521 addr += len;
522 // we are not assuming 'buf' to be zero initialized.
523 memset(buf, 0, len);
524 buf += len;
525 }
526 }
527
528 if (resid) {
529 print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n",
530 size, addr, resid);
531 return false;
532 } else {
533 return true;
534 }
535 }
536
537 // null implementation for write
538 static bool core_write_data(struct ps_prochandle* ph,
539 uintptr_t addr, const char *buf , size_t size) {
540 return false;
541 }
542
543 static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id,
544 struct user_regs_struct* regs) {
545 // for core we have cached the lwp regs from NOTE section
546 thread_info* thr = ph->threads;
547 while (thr) {
548 if (thr->lwp_id == lwp_id) {
549 memcpy(regs, &thr->regs, sizeof(struct user_regs_struct));
550 return true;
551 }
552 thr = thr->next;
553 }
554 return false;
555 }
556
557 static ps_prochandle_ops core_ops = {
558 .release= core_release,
559 .p_pread= core_read_data,
560 .p_pwrite= core_write_data,
561 .get_lwp_regs= core_get_lwp_regs
562 };
563
564 // read regs and create thread from NT_PRSTATUS entries from core file
565 static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) {
566 // we have to read prstatus_t from buf
567 // assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t");
568 prstatus_t* prstat = (prstatus_t*) buf;
569 thread_info* newthr;
570 print_debug("got integer regset for lwp %d\n", prstat->pr_pid);
571 // we set pthread_t to -1 for core dump
572 if((newthr = add_thread_info(ph, (pthread_t) -1, prstat->pr_pid)) == NULL)
573 return false;
574
575 // copy regs
576 memcpy(&newthr->regs, prstat->pr_reg, sizeof(struct user_regs_struct));
577
578 if (is_debug()) {
579 print_debug("integer regset\n");
580 #ifdef i386
581 // print the regset
582 print_debug("\teax = 0x%x\n", newthr->regs.eax);
583 print_debug("\tebx = 0x%x\n", newthr->regs.ebx);
584 print_debug("\tecx = 0x%x\n", newthr->regs.ecx);
585 print_debug("\tedx = 0x%x\n", newthr->regs.edx);
586 print_debug("\tesp = 0x%x\n", newthr->regs.esp);
587 print_debug("\tebp = 0x%x\n", newthr->regs.ebp);
588 print_debug("\tesi = 0x%x\n", newthr->regs.esi);
589 print_debug("\tedi = 0x%x\n", newthr->regs.edi);
590 print_debug("\teip = 0x%x\n", newthr->regs.eip);
591 #endif
592
593 #if defined(amd64) || defined(x86_64)
594 // print the regset
595 print_debug("\tr15 = 0x%lx\n", newthr->regs.r15);
596 print_debug("\tr14 = 0x%lx\n", newthr->regs.r14);
597 print_debug("\tr13 = 0x%lx\n", newthr->regs.r13);
598 print_debug("\tr12 = 0x%lx\n", newthr->regs.r12);
599 print_debug("\trbp = 0x%lx\n", newthr->regs.rbp);
600 print_debug("\trbx = 0x%lx\n", newthr->regs.rbx);
601 print_debug("\tr11 = 0x%lx\n", newthr->regs.r11);
602 print_debug("\tr10 = 0x%lx\n", newthr->regs.r10);
603 print_debug("\tr9 = 0x%lx\n", newthr->regs.r9);
604 print_debug("\tr8 = 0x%lx\n", newthr->regs.r8);
605 print_debug("\trax = 0x%lx\n", newthr->regs.rax);
606 print_debug("\trcx = 0x%lx\n", newthr->regs.rcx);
607 print_debug("\trdx = 0x%lx\n", newthr->regs.rdx);
608 print_debug("\trsi = 0x%lx\n", newthr->regs.rsi);
609 print_debug("\trdi = 0x%lx\n", newthr->regs.rdi);
610 print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax);
611 print_debug("\trip = 0x%lx\n", newthr->regs.rip);
612 print_debug("\tcs = 0x%lx\n", newthr->regs.cs);
613 print_debug("\teflags = 0x%lx\n", newthr->regs.eflags);
614 print_debug("\trsp = 0x%lx\n", newthr->regs.rsp);
615 print_debug("\tss = 0x%lx\n", newthr->regs.ss);
616 print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base);
617 print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base);
618 print_debug("\tds = 0x%lx\n", newthr->regs.ds);
619 print_debug("\tes = 0x%lx\n", newthr->regs.es);
620 print_debug("\tfs = 0x%lx\n", newthr->regs.fs);
621 print_debug("\tgs = 0x%lx\n", newthr->regs.gs);
622 #endif
623 }
624
625 return true;
626 }
627
628 #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y))
629
630 // read NT_PRSTATUS entries from core NOTE segment
631 static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) {
632 char* buf = NULL;
633 char* p = NULL;
634 size_t size = note_phdr->p_filesz;
635
636 // we are interested in just prstatus entries. we will ignore the rest.
637 // Advance the seek pointer to the start of the PT_NOTE data
638 if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) {
639 print_debug("failed to lseek to PT_NOTE data\n");
640 return false;
641 }
642
643 // Now process the PT_NOTE structures. Each one is preceded by
644 // an Elf{32/64}_Nhdr structure describing its type and size.
645 if ( (buf = (char*) malloc(size)) == NULL) {
646 print_debug("can't allocate memory for reading core notes\n");
647 goto err;
648 }
649
650 // read notes into buffer
651 if (read(ph->core->core_fd, buf, size) != size) {
652 print_debug("failed to read notes, core file must have been truncated\n");
653 goto err;
654 }
655
656 p = buf;
657 while (p < buf + size) {
658 ELF_NHDR* notep = (ELF_NHDR*) p;
659 char* descdata = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4);
660 print_debug("Note header with n_type = %d and n_descsz = %u\n",
661 notep->n_type, notep->n_descsz);
662
663 if (notep->n_type == NT_PRSTATUS) {
664 if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true) {
665 return false;
666 }
667 } else if (notep->n_type == NT_AUXV) {
668 // Get first segment from entry point
669 ELF_AUXV *auxv = (ELF_AUXV *)descdata;
670 while (auxv->a_type != AT_NULL) {
671 if (auxv->a_type == AT_ENTRY) {
672 // Set entry point address to address of dynamic section.
673 // We will adjust it in read_exec_segments().
674 ph->core->dynamic_addr = auxv->a_un.a_val;
675 break;
676 }
677 auxv++;
678 }
679 }
680 p = descdata + ROUNDUP(notep->n_descsz, 4);
681 }
682
683 free(buf);
684 return true;
685
686 err:
687 if (buf) free(buf);
688 return false;
689 }
690
691 // read all segments from core file
692 static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) {
693 int i = 0;
694 ELF_PHDR* phbuf = NULL;
695 ELF_PHDR* core_php = NULL;
696
697 if ((phbuf = read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL)
698 return false;
699
700 /*
701 * Now iterate through the program headers in the core file.
702 * We're interested in two types of Phdrs: PT_NOTE (which
703 * contains a set of saved /proc structures), and PT_LOAD (which
704 * represents a memory mapping from the process's address space).
705 *
706 * Difference b/w Solaris PT_NOTE and Linux/BSD PT_NOTE:
707 *
708 * In Solaris there are two PT_NOTE segments the first PT_NOTE (if present)
709 * contains /proc structs in the pre-2.6 unstructured /proc format. the last
710 * PT_NOTE has data in new /proc format.
711 *
712 * In Solaris, there is only one pstatus (process status). pstatus contains
713 * integer register set among other stuff. For each LWP, we have one lwpstatus
714 * entry that has integer regset for that LWP.
715 *
716 * Linux threads are actually 'clone'd processes. To support core analysis
717 * of "multithreaded" process, Linux creates more than one pstatus (called
718 * "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one
719 * "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular
720 * function "elf_core_dump".
721 */
722
723 for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) {
724 switch (core_php->p_type) {
725 case PT_NOTE:
726 if (core_handle_note(ph, core_php) != true) {
727 goto err;
728 }
729 break;
730
731 case PT_LOAD: {
732 if (core_php->p_filesz != 0) {
733 if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
734 core_php->p_vaddr, core_php->p_filesz) == NULL) goto err;
735 }
736 break;
737 }
738 }
739
740 core_php++;
741 }
742
743 free(phbuf);
744 return true;
745 err:
746 free(phbuf);
747 return false;
748 }
749
750 // read segments of a shared object
751 static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) {
752 int i = 0;
753 ELF_PHDR* phbuf;
754 ELF_PHDR* lib_php = NULL;
755
756 int page_size = sysconf(_SC_PAGE_SIZE);
757
758 if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL) {
759 return false;
760 }
761
762 // we want to process only PT_LOAD segments that are not writable.
763 // i.e., text segments. The read/write/exec (data) segments would
764 // have been already added from core file segments.
765 for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) {
766 if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) {
767
768 uintptr_t target_vaddr = lib_php->p_vaddr + lib_base;
769 map_info *existing_map = core_lookup(ph, target_vaddr);
770
771 if (existing_map == NULL){
772 if (add_map_info(ph, lib_fd, lib_php->p_offset,
773 target_vaddr, lib_php->p_memsz) == NULL) {
774 goto err;
775 }
776 } else {
777 // Coredump stores value of p_memsz elf field
778 // rounded up to page boundary.
779
780 if ((existing_map->memsz != page_size) &&
781 (existing_map->fd != lib_fd) &&
782 (ROUNDUP(existing_map->memsz, page_size) != ROUNDUP(lib_php->p_memsz, page_size))) {
783
784 print_debug("address conflict @ 0x%lx (existing map size = %ld, size = %ld, flags = %d)\n",
785 target_vaddr, existing_map->memsz, lib_php->p_memsz, lib_php->p_flags);
786 goto err;
787 }
788
789 /* replace PT_LOAD segment with library segment */
790 print_debug("overwrote with new address mapping (memsz %ld -> %ld)\n",
791 existing_map->memsz, ROUNDUP(lib_php->p_memsz, page_size));
792
793 existing_map->fd = lib_fd;
794 existing_map->offset = lib_php->p_offset;
795 existing_map->memsz = ROUNDUP(lib_php->p_memsz, page_size);
796 }
797 }
798
799 lib_php++;
800 }
801
802 free(phbuf);
803 return true;
804 err:
805 free(phbuf);
806 return false;
807 }
808
809 // process segments from interpreter (ld.so or ld-linux.so)
810 static bool read_interp_segments(struct ps_prochandle* ph) {
811 ELF_EHDR interp_ehdr;
812
813 if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) {
814 print_debug("interpreter is not a valid ELF file\n");
815 return false;
816 }
817
818 if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) {
819 print_debug("can't read segments of interpreter\n");
820 return false;
821 }
822
823 return true;
824 }
825
826 // process segments of a a.out
827 static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) {
828 int i = 0;
829 ELF_PHDR* phbuf = NULL;
830 ELF_PHDR* exec_php = NULL;
831
832 if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL) {
833 return false;
834 }
835
836 for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) {
837 switch (exec_php->p_type) {
838
839 // add mappings for PT_LOAD segments
840 case PT_LOAD: {
841 // add only non-writable segments of non-zero filesz
842 if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
843 if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err;
844 }
845 break;
846 }
847
848 // read the interpreter and it's segments
849 case PT_INTERP: {
850 char interp_name[BUF_SIZE + 1];
851
852 // BUF_SIZE is PATH_MAX + NAME_MAX + 1.
853 if (exec_php->p_filesz > BUF_SIZE) {
854 goto err;
855 }
856 pread(ph->core->exec_fd, interp_name, exec_php->p_filesz, exec_php->p_offset);
857 interp_name[exec_php->p_filesz] = '\0';
858 print_debug("ELF interpreter %s\n", interp_name);
859 // read interpreter segments as well
860 if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) {
861 print_debug("can't open runtime loader\n");
862 goto err;
863 }
864 break;
865 }
866
867 // from PT_DYNAMIC we want to read address of first link_map addr
868 case PT_DYNAMIC: {
869 if (exec_ehdr->e_type == ET_EXEC) {
870 ph->core->dynamic_addr = exec_php->p_vaddr;
871 } else { // ET_DYN
872 // dynamic_addr has entry point of executable.
873 // Thus we should substract it.
874 ph->core->dynamic_addr += exec_php->p_vaddr - exec_ehdr->e_entry;
875 }
876 print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr);
877 break;
878 }
879
880 } // switch
881 exec_php++;
882 } // for
883
884 free(phbuf);
885 return true;
886 err:
887 free(phbuf);
888 return false;
889 }
890
891
892 #define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug, r_map)
893 #define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase)
894 #define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr)
895 #define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name)
896 #define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next)
897
898 // read shared library info from runtime linker's data structures.
899 // This work is done by librtlb_db in Solaris
900 static bool read_shared_lib_info(struct ps_prochandle* ph) {
901 uintptr_t addr = ph->core->dynamic_addr;
902 uintptr_t debug_base;
903 uintptr_t first_link_map_addr;
904 uintptr_t ld_base_addr;
905 uintptr_t link_map_addr;
906 uintptr_t lib_base_diff;
907 uintptr_t lib_base;
908 uintptr_t lib_name_addr;
909 char lib_name[BUF_SIZE];
910 ELF_DYN dyn;
911 ELF_EHDR elf_ehdr;
912 int lib_fd;
913
914 // _DYNAMIC has information of the form
915 // [tag] [data] [tag] [data] .....
916 // Both tag and data are pointer sized.
917 // We look for dynamic info with DT_DEBUG. This has shared object info.
918 // refer to struct r_debug in link.h
919
920 dyn.d_tag = DT_NULL;
921 while (dyn.d_tag != DT_DEBUG) {
922 if (ps_pdread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) {
923 print_debug("can't read debug info from _DYNAMIC\n");
924 return false;
925 }
926 addr += sizeof(ELF_DYN);
927 }
928
929 // we have got Dyn entry with DT_DEBUG
930 debug_base = dyn.d_un.d_ptr;
931 // at debug_base we have struct r_debug. This has first link map in r_map field
932 if (ps_pdread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET,
933 &first_link_map_addr, sizeof(uintptr_t)) != PS_OK) {
934 print_debug("can't read first link map address\n");
935 return false;
936 }
937
938 // read ld_base address from struct r_debug
939 if (ps_pdread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr,
940 sizeof(uintptr_t)) != PS_OK) {
941 print_debug("can't read ld base address\n");
942 return false;
943 }
944 ph->core->ld_base_addr = ld_base_addr;
945
946 print_debug("interpreter base address is 0x%lx\n", ld_base_addr);
947
948 // now read segments from interp (i.e ld.so or ld-linux.so or ld-elf.so)
949 if (read_interp_segments(ph) != true) {
950 return false;
951 }
952
953 // after adding interpreter (ld.so) mappings sort again
954 if (sort_map_array(ph) != true) {
955 return false;
956 }
957
958 print_debug("first link map is at 0x%lx\n", first_link_map_addr);
959
960 link_map_addr = first_link_map_addr;
961 while (link_map_addr != 0) {
962 // read library base address of the .so. Note that even though <sys/link.h> calls
963 // link_map->l_addr as "base address", this is * not * really base virtual
964 // address of the shared object. This is actually the difference b/w the virtual
965 // address mentioned in shared object and the actual virtual base where runtime
966 // linker loaded it. We use "base diff" in read_lib_segments call below.
967
968 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET,
969 &lib_base_diff, sizeof(uintptr_t)) != PS_OK) {
970 print_debug("can't read shared object base address diff\n");
971 return false;
972 }
973
974 // read address of the name
975 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET,
976 &lib_name_addr, sizeof(uintptr_t)) != PS_OK) {
977 print_debug("can't read address of shared object name\n");
978 return false;
979 }
980
981 // read name of the shared object
982 lib_name[0] = '\0';
983 if (lib_name_addr != 0 &&
984 read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) {
985 print_debug("can't read shared object name\n");
986 // don't let failure to read the name stop opening the file. If something is really wrong
987 // it will fail later.
988 }
989
990 if (lib_name[0] != '\0') {
991 // ignore empty lib names
992 lib_fd = pathmap_open(lib_name);
993
994 if (lib_fd < 0) {
995 print_debug("can't open shared object %s\n", lib_name);
996 // continue with other libraries...
997 } else {
998 if (read_elf_header(lib_fd, &elf_ehdr)) {
999 lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
1000 print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
1001 lib_name, lib_base, lib_base_diff);
1002 // while adding library mappings we need to use "base difference".
1003 if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) {
1004 print_debug("can't read shared object's segments\n");
1005 close(lib_fd);
1006 return false;
1007 }
1008 add_lib_info_fd(ph, lib_name, lib_fd, lib_base);
1009 // Map info is added for the library (lib_name) so
1010 // we need to re-sort it before calling the p_pdread.
1011 if (sort_map_array(ph) != true)
1012 return false;
1013 } else {
1014 print_debug("can't read ELF header for shared object %s\n", lib_name);
1015 close(lib_fd);
1016 // continue with other libraries...
1017 }
1018 }
1019 }
1020
1021 // read next link_map address
1022 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET,
1023 &link_map_addr, sizeof(uintptr_t)) != PS_OK) {
1024 print_debug("can't read next link in link_map\n");
1025 return false;
1026 }
1027 }
1028
1029 return true;
1030 }
1031
1032 // the one and only one exposed stuff from this file
1033 JNIEXPORT struct ps_prochandle* JNICALL
1034 Pgrab_core(const char* exec_file, const char* core_file) {
1035 ELF_EHDR core_ehdr;
1036 ELF_EHDR exec_ehdr;
1037 ELF_EHDR lib_ehdr;
1038
1039 struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle));
1040 if (ph == NULL) {
1041 print_debug("can't allocate ps_prochandle\n");
1042 return NULL;
1043 }
1044
1045 if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) {
1046 free(ph);
1047 print_debug("can't allocate ps_prochandle\n");
1048 return NULL;
1049 }
1050
1051 // initialize ph
1052 ph->ops = &core_ops;
1053 ph->core->core_fd = -1;
1054 ph->core->exec_fd = -1;
1055 ph->core->interp_fd = -1;
1056
1057 // open the core file
1058 if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) {
1059 print_debug("can't open core file\n");
1060 goto err;
1061 }
1062
1063 // read core file ELF header
1064 if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) {
1065 print_debug("core file is not a valid ELF ET_CORE file\n");
1066 goto err;
1067 }
1068
1069 if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) {
1070 print_debug("can't open executable file\n");
1071 goto err;
1072 }
1073
1074 if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true ||
1075 ((exec_ehdr.e_type != ET_EXEC) && (exec_ehdr.e_type != ET_DYN))) {
1076 print_debug("executable file is not a valid ELF file\n");
1077 goto err;
1078 }
1079
1080 // process core file segments
1081 if (read_core_segments(ph, &core_ehdr) != true) {
1082 goto err;
1083 }
1084
1085 // process exec file segments
1086 if (read_exec_segments(ph, &exec_ehdr) != true) {
1087 goto err;
1088 }
1089
1090 // exec file is also treated like a shared object for symbol search
1091 if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd,
1092 (uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL) {
1093 goto err;
1094 }
1095
1096 // allocate and sort maps into map_array, we need to do this
1097 // here because read_shared_lib_info needs to read from debuggee
1098 // address space
1099 if (sort_map_array(ph) != true) {
1100 goto err;
1101 }
1102
1103 if (read_shared_lib_info(ph) != true) {
1104 goto err;
1105 }
1106
1107 // sort again because we have added more mappings from shared objects
1108 if (sort_map_array(ph) != true) {
1109 goto err;
1110 }
1111
1112 if (init_classsharing_workaround(ph) != true) {
1113 goto err;
1114 }
1115
1116 return ph;
1117
1118 err:
1119 Prelease(ph);
1120 return NULL;
1121 }