1 /*
2 * Copyright (c) 2003, 2012, 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_elf_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) close(fd);
68 lib = lib->next;
69 }
70 }
71
72 // clean all map_info stuff
73 static void destroy_map_info(struct ps_prochandle* ph) {
74 map_info* map = ph->core->maps;
75 while (map) {
76 map_info* next = map->next;
77 free(map);
78 map = next;
79 }
80
81 if (ph->core->map_array) {
82 free(ph->core->map_array);
83 }
84
85 // Part of the class sharing workaround
86 map = ph->core->class_share_maps;
87 while (map) {
88 map_info* next = map->next;
89 free(map);
90 map = next;
91 }
92 }
93
94 // ps_prochandle operations
95 static void core_release(struct ps_prochandle* ph) {
96 if (ph->core) {
97 close_elf_files(ph);
98 destroy_map_info(ph);
99 free(ph->core);
100 }
101 }
102
103 static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
104 map_info* map;
105 if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
106 print_debug("can't allocate memory for map_info\n");
107 return NULL;
108 }
109
110 // initialize map
111 map->fd = fd;
112 map->offset = offset;
113 map->vaddr = vaddr;
114 map->memsz = memsz;
115 return map;
116 }
117
118 // add map info with given fd, offset, vaddr and memsz
119 static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
120 uintptr_t vaddr, size_t memsz) {
121 map_info* map;
122 if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
123 return NULL;
124 }
125
126 // add this to map list
127 map->next = ph->core->maps;
128 ph->core->maps = map;
129 ph->core->num_maps++;
130
131 return map;
132 }
133
134 // Part of the class sharing workaround
135 static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
136 uintptr_t vaddr, size_t memsz) {
137 map_info* map;
138 if ((map = allocate_init_map(ph->core->classes_jsa_fd,
139 offset, vaddr, memsz)) == NULL) {
140 return NULL;
141 }
142
143 map->next = ph->core->class_share_maps;
144 ph->core->class_share_maps = map;
145 return map;
146 }
147
148 // Return the map_info for the given virtual address. We keep a sorted
149 // array of pointers in ph->map_array, so we can binary search.
150 static map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr)
151 {
152 int mid, lo = 0, hi = ph->core->num_maps - 1;
153 map_info *mp;
154
155 while (hi - lo > 1) {
156 mid = (lo + hi) / 2;
157 if (addr >= ph->core->map_array[mid]->vaddr)
158 lo = mid;
159 else
160 hi = mid;
161 }
162
163 if (addr < ph->core->map_array[hi]->vaddr)
164 mp = ph->core->map_array[lo];
165 else
166 mp = ph->core->map_array[hi];
167
168 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz)
169 return (mp);
170
171
172 // Part of the class sharing workaround
173 // Unfortunately, we have no way of detecting -Xshare state.
174 // Check out the share maps atlast, if we don't find anywhere.
175 // This is done this way so to avoid reading share pages
176 // ahead of other normal maps. For eg. with -Xshare:off we don't
177 // want to prefer class sharing data to data from core.
178 mp = ph->core->class_share_maps;
179 if (mp) {
180 print_debug("can't locate map_info at 0x%lx, trying class share maps\n",
181 addr);
182 }
183 while (mp) {
184 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
185 print_debug("located map_info at 0x%lx from class share maps\n",
186 addr);
187 return (mp);
188 }
189 mp = mp->next;
190 }
191
192 print_debug("can't locate map_info at 0x%lx\n", addr);
193 return (NULL);
194 }
195
196 //---------------------------------------------------------------
197 // Part of the class sharing workaround:
198 //
199 // With class sharing, pages are mapped from classes[_g].jsa file.
200 // The read-only class sharing pages are mapped as MAP_SHARED,
201 // PROT_READ pages. These pages are not dumped into core dump.
202 // With this workaround, these pages are read from classes[_g].jsa.
203
204 // FIXME: !HACK ALERT!
205 // The format of sharing achive file header is needed to read shared heap
206 // file mappings. For now, I am hard coding portion of FileMapHeader here.
207 // Refer to filemap.hpp.
208
209 // FileMapHeader describes the shared space data in the file to be
210 // mapped. This structure gets written to a file. It is not a class,
211 // so that the compilers don't add any compiler-private data to it.
212
213 #define NUM_SHARED_MAPS 4
214
215 // Refer to FileMapInfo::_current_version in filemap.hpp
216 #define CURRENT_ARCHIVE_VERSION 1
217
218 struct FileMapHeader {
219 int _magic; // identify file type.
220 int _version; // (from enum, above.)
221 size_t _alignment; // how shared archive should be aligned
222
223 struct space_info {
224 int _file_offset; // sizeof(this) rounded to vm page size
225 char* _base; // copy-on-write base address
226 size_t _capacity; // for validity checking
227 size_t _used; // for setting space top on read
228
229 // 4991491 NOTICE These are C++ bool's in filemap.hpp and must match up with
230 // the C type matching the C++ bool type on any given platform. For
231 // Hotspot on BSD we assume the corresponding C type is char but
232 // licensees on BSD versions may need to adjust the type of these fields.
233 char _read_only; // read only space?
234 char _allow_exec; // executable code in space?
235
236 } _space[NUM_SHARED_MAPS];
237
238 // Ignore the rest of the FileMapHeader. We don't need those fields here.
239 };
240
241 static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
242 jboolean i;
243 if (ps_pread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
244 *pvalue = i;
245 return true;
246 } else {
247 return false;
248 }
249 }
250
251 static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
252 uintptr_t uip;
253 if (ps_pread(ph, (psaddr_t) addr, &uip, sizeof(uip)) == PS_OK) {
254 *pvalue = uip;
255 return true;
256 } else {
257 return false;
258 }
259 }
260
261 // used to read strings from debuggee
262 static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
263 size_t i = 0;
264 char c = ' ';
265
266 while (c != '\0') {
267 if (ps_pread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK)
268 return false;
269 if (i < size - 1)
270 buf[i] = c;
271 else // smaller buffer
272 return false;
273 i++; addr++;
274 }
275
276 buf[i] = '\0';
277 return true;
278 }
279
280 #define USE_SHARED_SPACES_SYM "UseSharedSpaces"
281 // mangled name of Arguments::SharedArchivePath
282 #define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
283
284 static bool init_classsharing_workaround(struct ps_prochandle* ph) {
285 lib_info* lib = ph->libs;
286 while (lib != NULL) {
287 // we are iterating over shared objects from the core dump. look for
288 // libjvm[_g].so.
289 const char *jvm_name = 0;
290 if ((jvm_name = strstr(lib->name, "/libjvm.so")) != 0 ||
291 (jvm_name = strstr(lib->name, "/libjvm_g.so")) != 0) {
292 char classes_jsa[PATH_MAX];
293 struct FileMapHeader header;
294 size_t n = 0;
295 int fd = -1, m = 0;
296 uintptr_t base = 0, useSharedSpacesAddr = 0;
297 uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
298 jboolean useSharedSpaces = 0;
299
300 memset(classes_jsa, 0, sizeof(classes_jsa));
301 jvm_name = lib->name;
302 useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
303 if (useSharedSpacesAddr == 0) {
304 print_debug("can't lookup 'UseSharedSpaces' flag\n");
305 return false;
306 }
307
308 // Hotspot vm types are not exported to build this library. So
309 // using equivalent type jboolean to read the value of
310 // UseSharedSpaces which is same as hotspot type "bool".
311 if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
312 print_debug("can't read the value of 'UseSharedSpaces' flag\n");
313 return false;
314 }
315
316 if ((int)useSharedSpaces == 0) {
317 print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
318 return true;
319 }
320
321 sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
322 if (sharedArchivePathAddrAddr == 0) {
323 print_debug("can't lookup shared archive path symbol\n");
324 return false;
325 }
326
327 if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
328 print_debug("can't read shared archive path pointer\n");
329 return false;
330 }
331
332 if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
333 print_debug("can't read shared archive path value\n");
334 return false;
335 }
336
337 print_debug("looking for %s\n", classes_jsa);
338 // open the class sharing archive file
339 fd = pathmap_open(classes_jsa);
340 if (fd < 0) {
341 print_debug("can't open %s!\n", classes_jsa);
342 ph->core->classes_jsa_fd = -1;
343 return false;
344 } else {
345 print_debug("opened %s\n", classes_jsa);
346 }
347
348 // read FileMapHeader from the file
349 memset(&header, 0, sizeof(struct FileMapHeader));
350 if ((n = read(fd, &header, sizeof(struct FileMapHeader)))
351 != sizeof(struct FileMapHeader)) {
352 print_debug("can't read shared archive file map header from %s\n", classes_jsa);
353 close(fd);
354 return false;
355 }
356
357 // check file magic
358 if (header._magic != 0xf00baba2) {
359 print_debug("%s has bad shared archive file magic number 0x%x, expecing 0xf00baba2\n",
360 classes_jsa, header._magic);
361 close(fd);
362 return false;
363 }
364
365 // check version
366 if (header._version != CURRENT_ARCHIVE_VERSION) {
367 print_debug("%s has wrong shared archive file version %d, expecting %d\n",
368 classes_jsa, header._version, CURRENT_ARCHIVE_VERSION);
369 close(fd);
370 return false;
371 }
372
373 ph->core->classes_jsa_fd = fd;
374 // add read-only maps from classes[_g].jsa to the list of maps
375 for (m = 0; m < NUM_SHARED_MAPS; m++) {
376 if (header._space[m]._read_only) {
377 base = (uintptr_t) header._space[m]._base;
378 // no need to worry about the fractional pages at-the-end.
379 // possible fractional pages are handled by core_read_data.
380 add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
381 base, (size_t) header._space[m]._used);
382 print_debug("added a share archive map at 0x%lx\n", base);
383 }
384 }
385 return true;
386 }
387 lib = lib->next;
388 }
389 return true;
390 }
391
392
393 //---------------------------------------------------------------------------
394 // functions to handle map_info
395
396 // Order mappings based on virtual address. We use this function as the
397 // callback for sorting the array of map_info pointers.
398 static int core_cmp_mapping(const void *lhsp, const void *rhsp)
399 {
400 const map_info *lhs = *((const map_info **)lhsp);
401 const map_info *rhs = *((const map_info **)rhsp);
402
403 if (lhs->vaddr == rhs->vaddr)
404 return (0);
405
406 return (lhs->vaddr < rhs->vaddr ? -1 : 1);
407 }
408
409 // we sort map_info by starting virtual address so that we can do
410 // binary search to read from an address.
411 static bool sort_map_array(struct ps_prochandle* ph) {
412 size_t num_maps = ph->core->num_maps;
413 map_info* map = ph->core->maps;
414 int i = 0;
415
416 // allocate map_array
417 map_info** array;
418 if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) {
419 print_debug("can't allocate memory for map array\n");
420 return false;
421 }
422
423 // add maps to array
424 while (map) {
425 array[i] = map;
426 i++;
427 map = map->next;
428 }
429
430 // sort is called twice. If this is second time, clear map array
431 if (ph->core->map_array) free(ph->core->map_array);
432 ph->core->map_array = array;
433 // sort the map_info array by base virtual address.
434 qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*),
435 core_cmp_mapping);
436
437 // print map
438 if (is_debug()) {
439 int j = 0;
440 print_debug("---- sorted virtual address map ----\n");
441 for (j = 0; j < ph->core->num_maps; j++) {
442 print_debug("base = 0x%lx\tsize = %d\n", ph->core->map_array[j]->vaddr,
443 ph->core->map_array[j]->memsz);
444 }
445 }
446
447 return true;
448 }
449
450 #ifndef MIN
451 #define MIN(x, y) (((x) < (y))? (x): (y))
452 #endif
453
454 static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
455 ssize_t resid = size;
456 int page_size=sysconf(_SC_PAGE_SIZE);
457 while (resid != 0) {
458 map_info *mp = core_lookup(ph, addr);
459 uintptr_t mapoff;
460 ssize_t len, rem;
461 off_t off;
462 int fd;
463
464 if (mp == NULL)
465 break; /* No mapping for this address */
466
467 fd = mp->fd;
468 mapoff = addr - mp->vaddr;
469 len = MIN(resid, mp->memsz - mapoff);
470 off = mp->offset + mapoff;
471
472 if ((len = pread(fd, buf, len, off)) <= 0)
473 break;
474
475 resid -= len;
476 addr += len;
477 buf = (char *)buf + len;
478
479 // mappings always start at page boundary. But, may end in fractional
480 // page. fill zeros for possible fractional page at the end of a mapping.
481 rem = mp->memsz % page_size;
482 if (rem > 0) {
483 rem = page_size - rem;
484 len = MIN(resid, rem);
485 resid -= len;
486 addr += len;
487 // we are not assuming 'buf' to be zero initialized.
488 memset(buf, 0, len);
489 buf += len;
490 }
491 }
492
493 if (resid) {
494 print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n",
495 size, addr, resid);
496 return false;
497 } else {
498 return true;
499 }
500 }
501
502 // null implementation for write
503 static bool core_write_data(struct ps_prochandle* ph,
504 uintptr_t addr, const char *buf , size_t size) {
505 return false;
506 }
507
508 static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id,
509 struct reg* regs) {
510 // for core we have cached the lwp regs from NOTE section
511 thread_info* thr = ph->threads;
512 while (thr) {
513 if (thr->lwp_id == lwp_id) {
514 memcpy(regs, &thr->regs, sizeof(struct reg));
515 return true;
516 }
517 thr = thr->next;
518 }
519 return false;
520 }
521
522 static bool core_get_lwp_info(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) {
523 print_debug("core_get_lwp_info not implemented\n");
524 return false;
525 }
526
527 static ps_prochandle_ops core_ops = {
528 .release= core_release,
529 .p_pread= core_read_data,
530 .p_pwrite= core_write_data,
531 .get_lwp_regs= core_get_lwp_regs,
532 .get_lwp_info= core_get_lwp_info
533 };
534
535 // read regs and create thread from NT_PRSTATUS entries from core file
536 static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) {
537 // we have to read prstatus_t from buf
538 // assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t");
539 prstatus_t* prstat = (prstatus_t*) buf;
540 thread_info* newthr;
541 print_debug("got integer regset for lwp %d\n", prstat->pr_pid);
542 // we set pthread_t to -1 for core dump
543 if((newthr = add_thread_info(ph, (pthread_t) -1, prstat->pr_pid)) == NULL)
544 return false;
545
546 // copy regs
547 memcpy(&newthr->regs, &prstat->pr_reg, sizeof(struct reg));
548
549 if (is_debug()) {
550 print_debug("integer regset\n");
551 #ifdef i386
552 // print the regset
553 print_debug("\teax = 0x%x\n", newthr->regs.r_eax);
554 print_debug("\tebx = 0x%x\n", newthr->regs.r_ebx);
555 print_debug("\tecx = 0x%x\n", newthr->regs.r_ecx);
556 print_debug("\tedx = 0x%x\n", newthr->regs.r_edx);
557 print_debug("\tesp = 0x%x\n", newthr->regs.r_esp);
558 print_debug("\tebp = 0x%x\n", newthr->regs.r_ebp);
559 print_debug("\tesi = 0x%x\n", newthr->regs.r_esi);
560 print_debug("\tedi = 0x%x\n", newthr->regs.r_edi);
561 print_debug("\teip = 0x%x\n", newthr->regs.r_eip);
562 #endif
563
564 #if defined(amd64) || defined(x86_64)
565 // print the regset
566 print_debug("\tr15 = 0x%lx\n", newthr->regs.r_r15);
567 print_debug("\tr14 = 0x%lx\n", newthr->regs.r_r14);
568 print_debug("\tr13 = 0x%lx\n", newthr->regs.r_r13);
569 print_debug("\tr12 = 0x%lx\n", newthr->regs.r_r12);
570 print_debug("\trbp = 0x%lx\n", newthr->regs.r_rbp);
571 print_debug("\trbx = 0x%lx\n", newthr->regs.r_rbx);
572 print_debug("\tr11 = 0x%lx\n", newthr->regs.r_r11);
573 print_debug("\tr10 = 0x%lx\n", newthr->regs.r_r10);
574 print_debug("\tr9 = 0x%lx\n", newthr->regs.r_r9);
575 print_debug("\tr8 = 0x%lx\n", newthr->regs.r_r8);
576 print_debug("\trax = 0x%lx\n", newthr->regs.r_rax);
577 print_debug("\trcx = 0x%lx\n", newthr->regs.r_rcx);
578 print_debug("\trdx = 0x%lx\n", newthr->regs.r_rdx);
579 print_debug("\trsi = 0x%lx\n", newthr->regs.r_rsi);
580 print_debug("\trdi = 0x%lx\n", newthr->regs.r_rdi);
581 //print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax);
582 print_debug("\trip = 0x%lx\n", newthr->regs.r_rip);
583 print_debug("\tcs = 0x%lx\n", newthr->regs.r_cs);
584 //print_debug("\teflags = 0x%lx\n", newthr->regs.eflags);
585 print_debug("\trsp = 0x%lx\n", newthr->regs.r_rsp);
586 print_debug("\tss = 0x%lx\n", newthr->regs.r_ss);
587 //print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base);
588 //print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base);
589 //print_debug("\tds = 0x%lx\n", newthr->regs.ds);
590 //print_debug("\tes = 0x%lx\n", newthr->regs.es);
591 //print_debug("\tfs = 0x%lx\n", newthr->regs.fs);
592 //print_debug("\tgs = 0x%lx\n", newthr->regs.gs);
593 #endif
594 }
595
596 return true;
597 }
598
599 #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y))
600
601 // read NT_PRSTATUS entries from core NOTE segment
602 static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) {
603 char* buf = NULL;
604 char* p = NULL;
605 size_t size = note_phdr->p_filesz;
606
607 // we are interested in just prstatus entries. we will ignore the rest.
608 // Advance the seek pointer to the start of the PT_NOTE data
609 if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) {
610 print_debug("failed to lseek to PT_NOTE data\n");
611 return false;
612 }
613
614 // Now process the PT_NOTE structures. Each one is preceded by
615 // an Elf{32/64}_Nhdr structure describing its type and size.
616 if ( (buf = (char*) malloc(size)) == NULL) {
617 print_debug("can't allocate memory for reading core notes\n");
618 goto err;
619 }
620
621 // read notes into buffer
622 if (read(ph->core->core_fd, buf, size) != size) {
623 print_debug("failed to read notes, core file must have been truncated\n");
624 goto err;
625 }
626
627 p = buf;
628 while (p < buf + size) {
629 ELF_NHDR* notep = (ELF_NHDR*) p;
630 char* descdata = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4);
631 print_debug("Note header with n_type = %d and n_descsz = %u\n",
632 notep->n_type, notep->n_descsz);
633
634 if (notep->n_type == NT_PRSTATUS) {
635 if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true)
636 return false;
637 }
638 p = descdata + ROUNDUP(notep->n_descsz, 4);
639 }
640
641 free(buf);
642 return true;
643
644 err:
645 if (buf) free(buf);
646 return false;
647 }
648
649 // read all segments from core file
650 static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) {
651 int i = 0;
652 ELF_PHDR* phbuf = NULL;
653 ELF_PHDR* core_php = NULL;
654
655 if ((phbuf = read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL)
656 return false;
657
658 /*
659 * Now iterate through the program headers in the core file.
660 * We're interested in two types of Phdrs: PT_NOTE (which
661 * contains a set of saved /proc structures), and PT_LOAD (which
662 * represents a memory mapping from the process's address space).
663 *
664 * Difference b/w Solaris PT_NOTE and BSD PT_NOTE:
665 *
666 * In Solaris there are two PT_NOTE segments the first PT_NOTE (if present)
667 * contains /proc structs in the pre-2.6 unstructured /proc format. the last
668 * PT_NOTE has data in new /proc format.
669 *
670 * In Solaris, there is only one pstatus (process status). pstatus contains
671 * integer register set among other stuff. For each LWP, we have one lwpstatus
672 * entry that has integer regset for that LWP.
673 *
674 * Linux threads are actually 'clone'd processes. To support core analysis
675 * of "multithreaded" process, Linux creates more than one pstatus (called
676 * "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one
677 * "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular
678 * function "elf_core_dump".
679 */
680
681 for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) {
682 switch (core_php->p_type) {
683 case PT_NOTE:
684 if (core_handle_note(ph, core_php) != true) goto err;
685 break;
686
687 case PT_LOAD: {
688 if (core_php->p_filesz != 0) {
689 if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
690 core_php->p_vaddr, core_php->p_filesz) == NULL) goto err;
691 }
692 break;
693 }
694 }
695
696 core_php++;
697 }
698
699 free(phbuf);
700 return true;
701 err:
702 free(phbuf);
703 return false;
704 }
705
706 // read segments of a shared object
707 static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) {
708 int i = 0;
709 ELF_PHDR* phbuf;
710 ELF_PHDR* lib_php = NULL;
711
712 if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL)
713 return false;
714
715 // we want to process only PT_LOAD segments that are not writable.
716 // i.e., text segments. The read/write/exec (data) segments would
717 // have been already added from core file segments.
718 for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) {
719 if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) {
720 if (add_map_info(ph, lib_fd, lib_php->p_offset, lib_php->p_vaddr + lib_base, lib_php->p_filesz) == NULL)
721 goto err;
722 }
723 lib_php++;
724 }
725
726 free(phbuf);
727 return true;
728 err:
729 free(phbuf);
730 return false;
731 }
732
733 // process segments from interpreter (ld-elf.so.1)
734 static bool read_interp_segments(struct ps_prochandle* ph) {
735 ELF_EHDR interp_ehdr;
736
737 if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) {
738 print_debug("interpreter is not a valid ELF file\n");
739 return false;
740 }
741
742 if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) {
743 print_debug("can't read segments of interpreter\n");
744 return false;
745 }
746
747 return true;
748 }
749
750 // process segments of a a.out
751 static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) {
752 int i = 0;
753 ELF_PHDR* phbuf = NULL;
754 ELF_PHDR* exec_php = NULL;
755
756 if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL)
757 return false;
758
759 for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) {
760 switch (exec_php->p_type) {
761
762 // add mappings for PT_LOAD segments
763 case PT_LOAD: {
764 // add only non-writable segments of non-zero filesz
765 if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
766 if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err;
767 }
768 break;
769 }
770
771 // read the interpreter and it's segments
772 case PT_INTERP: {
773 char interp_name[BUF_SIZE];
774
775 pread(ph->core->exec_fd, interp_name, MIN(exec_php->p_filesz, BUF_SIZE), exec_php->p_offset);
776 print_debug("ELF interpreter %s\n", interp_name);
777 // read interpreter segments as well
778 if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) {
779 print_debug("can't open runtime loader\n");
780 goto err;
781 }
782 break;
783 }
784
785 // from PT_DYNAMIC we want to read address of first link_map addr
786 case PT_DYNAMIC: {
787 ph->core->dynamic_addr = exec_php->p_vaddr;
788 print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr);
789 break;
790 }
791
792 } // switch
793 exec_php++;
794 } // for
795
796 free(phbuf);
797 return true;
798 err:
799 free(phbuf);
800 return false;
801 }
802
803
804 #define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug, r_map)
805 #define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase)
806 #define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr)
807 #define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name)
808 #define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next)
809
810 // read shared library info from runtime linker's data structures.
811 // This work is done by librtlb_db in Solaris
812 static bool read_shared_lib_info(struct ps_prochandle* ph) {
813 uintptr_t addr = ph->core->dynamic_addr;
814 uintptr_t debug_base;
815 uintptr_t first_link_map_addr;
816 uintptr_t ld_base_addr;
817 uintptr_t link_map_addr;
818 uintptr_t lib_base_diff;
819 uintptr_t lib_base;
820 uintptr_t lib_name_addr;
821 char lib_name[BUF_SIZE];
822 ELF_DYN dyn;
823 ELF_EHDR elf_ehdr;
824 int lib_fd;
825
826 // _DYNAMIC has information of the form
827 // [tag] [data] [tag] [data] .....
828 // Both tag and data are pointer sized.
829 // We look for dynamic info with DT_DEBUG. This has shared object info.
830 // refer to struct r_debug in link.h
831
832 dyn.d_tag = DT_NULL;
833 while (dyn.d_tag != DT_DEBUG) {
834 if (ps_pread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) {
835 print_debug("can't read debug info from _DYNAMIC\n");
836 return false;
837 }
838 addr += sizeof(ELF_DYN);
839 }
840
841 // we have got Dyn entry with DT_DEBUG
842 debug_base = dyn.d_un.d_ptr;
843 // at debug_base we have struct r_debug. This has first link map in r_map field
844 if (ps_pread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET,
845 &first_link_map_addr, sizeof(uintptr_t)) != PS_OK) {
846 print_debug("can't read first link map address\n");
847 return false;
848 }
849
850 // read ld_base address from struct r_debug
851 // XXX: There is no r_ldbase member on BSD
852 /*
853 if (ps_pread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr,
854 sizeof(uintptr_t)) != PS_OK) {
855 print_debug("can't read ld base address\n");
856 return false;
857 }
858 ph->core->ld_base_addr = ld_base_addr;
859 */
860 ph->core->ld_base_addr = 0;
861
862 print_debug("interpreter base address is 0x%lx\n", ld_base_addr);
863
864 // now read segments from interp (i.e ld-elf.so.1)
865 if (read_interp_segments(ph) != true)
866 return false;
867
868 // after adding interpreter (ld.so) mappings sort again
869 if (sort_map_array(ph) != true)
870 return false;
871
872 print_debug("first link map is at 0x%lx\n", first_link_map_addr);
873
874 link_map_addr = first_link_map_addr;
875 while (link_map_addr != 0) {
876 // read library base address of the .so. Note that even though <sys/link.h> calls
877 // link_map->l_addr as "base address", this is * not * really base virtual
878 // address of the shared object. This is actually the difference b/w the virtual
879 // address mentioned in shared object and the actual virtual base where runtime
880 // linker loaded it. We use "base diff" in read_lib_segments call below.
881
882 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET,
883 &lib_base_diff, sizeof(uintptr_t)) != PS_OK) {
884 print_debug("can't read shared object base address diff\n");
885 return false;
886 }
887
888 // read address of the name
889 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET,
890 &lib_name_addr, sizeof(uintptr_t)) != PS_OK) {
891 print_debug("can't read address of shared object name\n");
892 return false;
893 }
894
895 // read name of the shared object
896 if (read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) {
897 print_debug("can't read shared object name\n");
898 return false;
899 }
900
901 if (lib_name[0] != '\0') {
902 // ignore empty lib names
903 lib_fd = pathmap_open(lib_name);
904
905 if (lib_fd < 0) {
906 print_debug("can't open shared object %s\n", lib_name);
907 // continue with other libraries...
908 } else {
909 if (read_elf_header(lib_fd, &elf_ehdr)) {
910 lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
911 print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
912 lib_name, lib_base, lib_base_diff);
913 // while adding library mappings we need to use "base difference".
914 if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) {
915 print_debug("can't read shared object's segments\n");
916 close(lib_fd);
917 return false;
918 }
919 add_lib_info_fd(ph, lib_name, lib_fd, lib_base);
920 // Map info is added for the library (lib_name) so
921 // we need to re-sort it before calling the p_pdread.
922 if (sort_map_array(ph) != true)
923 return false;
924 } else {
925 print_debug("can't read ELF header for shared object %s\n", lib_name);
926 close(lib_fd);
927 // continue with other libraries...
928 }
929 }
930 }
931
932 // read next link_map address
933 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET,
934 &link_map_addr, sizeof(uintptr_t)) != PS_OK) {
935 print_debug("can't read next link in link_map\n");
936 return false;
937 }
938 }
939
940 return true;
941 }
942
943 // the one and only one exposed stuff from this file
944 struct ps_prochandle* Pgrab_core(const char* exec_file, const char* core_file) {
945 ELF_EHDR core_ehdr;
946 ELF_EHDR exec_ehdr;
947
948 struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle));
949 if (ph == NULL) {
950 print_debug("can't allocate ps_prochandle\n");
951 return NULL;
952 }
953
954 if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) {
955 free(ph);
956 print_debug("can't allocate ps_prochandle\n");
957 return NULL;
958 }
959
960 // initialize ph
961 ph->ops = &core_ops;
962 ph->core->core_fd = -1;
963 ph->core->exec_fd = -1;
964 ph->core->interp_fd = -1;
965
966 // open the core file
967 if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) {
968 print_debug("can't open core file\n");
969 goto err;
970 }
971
972 // read core file ELF header
973 if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) {
974 print_debug("core file is not a valid ELF ET_CORE file\n");
975 goto err;
976 }
977
978 if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) {
979 print_debug("can't open executable file\n");
980 goto err;
981 }
982
983 if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true || exec_ehdr.e_type != ET_EXEC) {
984 print_debug("executable file is not a valid ELF ET_EXEC file\n");
985 goto err;
986 }
987
988 // process core file segments
989 if (read_core_segments(ph, &core_ehdr) != true)
990 goto err;
991
992 // process exec file segments
993 if (read_exec_segments(ph, &exec_ehdr) != true)
994 goto err;
995
996 // exec file is also treated like a shared object for symbol search
997 if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd,
998 (uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL)
999 goto err;
1000
1001 // allocate and sort maps into map_array, we need to do this
1002 // here because read_shared_lib_info needs to read from debuggee
1003 // address space
1004 if (sort_map_array(ph) != true)
1005 goto err;
1006
1007 if (read_shared_lib_info(ph) != true)
1008 goto err;
1009
1010 // sort again because we have added more mappings from shared objects
1011 if (sort_map_array(ph) != true)
1012 goto err;
1013
1014 if (init_classsharing_workaround(ph) != true)
1015 goto err;
1016
1017 return ph;
1018
1019 err:
1020 Prelease(ph);
1021 return NULL;
1022 }