1 /*
2 * Copyright (c) 2003, 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 #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 "ps_core_common.h"
35 #include "proc_service.h"
36 #include "salibelf.h"
37
38 // This file has the libproc implementation to read core files.
39 // For live processes, refer to ps_proc.c. Portions of this is adapted
40 // /modelled after Solaris libproc.so (in particular Pcore.c)
41
42
43 //---------------------------------------------------------------------------
44 // functions to handle map_info
45
46 // Order mappings based on virtual address. We use this function as the
47 // callback for sorting the array of map_info pointers.
48 static int core_cmp_mapping(const void *lhsp, const void *rhsp)
49 {
50 const map_info *lhs = *((const map_info **)lhsp);
51 const map_info *rhs = *((const map_info **)rhsp);
52
53 if (lhs->vaddr == rhs->vaddr) {
54 return (0);
55 }
56
57 return (lhs->vaddr < rhs->vaddr ? -1 : 1);
58 }
59
60 // we sort map_info by starting virtual address so that we can do
61 // binary search to read from an address.
62 static bool sort_map_array(struct ps_prochandle* ph) {
63 size_t num_maps = ph->core->num_maps;
64 map_info* map = ph->core->maps;
65 int i = 0;
66
67 // allocate map_array
68 map_info** array;
69 if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) {
70 print_debug("can't allocate memory for map array\n");
71 return false;
72 }
73
74 // add maps to array
75 while (map) {
76 array[i] = map;
77 i++;
78 map = map->next;
79 }
80
81 // sort is called twice. If this is second time, clear map array
82 if (ph->core->map_array) {
83 free(ph->core->map_array);
84 }
85
86 ph->core->map_array = array;
87 // sort the map_info array by base virtual address.
88 qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*),
89 core_cmp_mapping);
90
91 // print map
92 if (is_debug()) {
93 int j = 0;
94 print_debug("---- sorted virtual address map ----\n");
95 for (j = 0; j < ph->core->num_maps; j++) {
96 print_debug("base = 0x%lx\tsize = %zu\n", ph->core->map_array[j]->vaddr,
97 ph->core->map_array[j]->memsz);
98 }
99 }
100
101 return true;
102 }
103
104 #ifndef MIN
105 #define MIN(x, y) (((x) < (y))? (x): (y))
106 #endif
107
108 static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
109 ssize_t resid = size;
110 int page_size=sysconf(_SC_PAGE_SIZE);
111 while (resid != 0) {
112 map_info *mp = core_lookup(ph, addr);
113 uintptr_t mapoff;
114 ssize_t len, rem;
115 off_t off;
116 int fd;
117
118 if (mp == NULL) {
119 break; /* No mapping for this address */
120 }
121
122 fd = mp->fd;
123 mapoff = addr - mp->vaddr;
124 len = MIN(resid, mp->memsz - mapoff);
125 off = mp->offset + mapoff;
126
127 if ((len = pread(fd, buf, len, off)) <= 0) {
128 break;
129 }
130
131 resid -= len;
132 addr += len;
133 buf = (char *)buf + len;
134
135 // mappings always start at page boundary. But, may end in fractional
136 // page. fill zeros for possible fractional page at the end of a mapping.
137 rem = mp->memsz % page_size;
138 if (rem > 0) {
139 rem = page_size - rem;
140 len = MIN(resid, rem);
141 resid -= len;
142 addr += len;
143 // we are not assuming 'buf' to be zero initialized.
144 memset(buf, 0, len);
145 buf += len;
146 }
147 }
148
149 if (resid) {
150 print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n",
151 size, addr, resid);
152 return false;
153 } else {
154 return true;
155 }
156 }
157
158 // null implementation for write
159 static bool core_write_data(struct ps_prochandle* ph,
160 uintptr_t addr, const char *buf , size_t size) {
161 return false;
162 }
163
164 static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id,
165 struct user_regs_struct* regs) {
166 // for core we have cached the lwp regs from NOTE section
167 thread_info* thr = ph->threads;
168 while (thr) {
169 if (thr->lwp_id == lwp_id) {
170 memcpy(regs, &thr->regs, sizeof(struct user_regs_struct));
171 return true;
172 }
173 thr = thr->next;
174 }
175 return false;
176 }
177
178 static ps_prochandle_ops core_ops = {
179 .release= core_release,
180 .p_pread= core_read_data,
181 .p_pwrite= core_write_data,
182 .get_lwp_regs= core_get_lwp_regs
183 };
184
185 // read regs and create thread from NT_PRSTATUS entries from core file
186 static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) {
187 // we have to read prstatus_t from buf
188 // assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t");
189 prstatus_t* prstat = (prstatus_t*) buf;
190 thread_info* newthr;
191 print_debug("got integer regset for lwp %d\n", prstat->pr_pid);
192 if((newthr = add_thread_info(ph, prstat->pr_pid)) == NULL)
193 return false;
194
195 // copy regs
196 memcpy(&newthr->regs, prstat->pr_reg, sizeof(struct user_regs_struct));
197
198 if (is_debug()) {
199 print_debug("integer regset\n");
200 #ifdef i386
201 // print the regset
202 print_debug("\teax = 0x%x\n", newthr->regs.eax);
203 print_debug("\tebx = 0x%x\n", newthr->regs.ebx);
204 print_debug("\tecx = 0x%x\n", newthr->regs.ecx);
205 print_debug("\tedx = 0x%x\n", newthr->regs.edx);
206 print_debug("\tesp = 0x%x\n", newthr->regs.esp);
207 print_debug("\tebp = 0x%x\n", newthr->regs.ebp);
208 print_debug("\tesi = 0x%x\n", newthr->regs.esi);
209 print_debug("\tedi = 0x%x\n", newthr->regs.edi);
210 print_debug("\teip = 0x%x\n", newthr->regs.eip);
211 #endif
212
213 #if defined(amd64) || defined(x86_64)
214 // print the regset
215 print_debug("\tr15 = 0x%lx\n", newthr->regs.r15);
216 print_debug("\tr14 = 0x%lx\n", newthr->regs.r14);
217 print_debug("\tr13 = 0x%lx\n", newthr->regs.r13);
218 print_debug("\tr12 = 0x%lx\n", newthr->regs.r12);
219 print_debug("\trbp = 0x%lx\n", newthr->regs.rbp);
220 print_debug("\trbx = 0x%lx\n", newthr->regs.rbx);
221 print_debug("\tr11 = 0x%lx\n", newthr->regs.r11);
222 print_debug("\tr10 = 0x%lx\n", newthr->regs.r10);
223 print_debug("\tr9 = 0x%lx\n", newthr->regs.r9);
224 print_debug("\tr8 = 0x%lx\n", newthr->regs.r8);
225 print_debug("\trax = 0x%lx\n", newthr->regs.rax);
226 print_debug("\trcx = 0x%lx\n", newthr->regs.rcx);
227 print_debug("\trdx = 0x%lx\n", newthr->regs.rdx);
228 print_debug("\trsi = 0x%lx\n", newthr->regs.rsi);
229 print_debug("\trdi = 0x%lx\n", newthr->regs.rdi);
230 print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax);
231 print_debug("\trip = 0x%lx\n", newthr->regs.rip);
232 print_debug("\tcs = 0x%lx\n", newthr->regs.cs);
233 print_debug("\teflags = 0x%lx\n", newthr->regs.eflags);
234 print_debug("\trsp = 0x%lx\n", newthr->regs.rsp);
235 print_debug("\tss = 0x%lx\n", newthr->regs.ss);
236 print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base);
237 print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base);
238 print_debug("\tds = 0x%lx\n", newthr->regs.ds);
239 print_debug("\tes = 0x%lx\n", newthr->regs.es);
240 print_debug("\tfs = 0x%lx\n", newthr->regs.fs);
241 print_debug("\tgs = 0x%lx\n", newthr->regs.gs);
242 #endif
243 }
244
245 return true;
246 }
247
248 #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y))
249
250 // read NT_PRSTATUS entries from core NOTE segment
251 static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) {
252 char* buf = NULL;
253 char* p = NULL;
254 size_t size = note_phdr->p_filesz;
255
256 // we are interested in just prstatus entries. we will ignore the rest.
257 // Advance the seek pointer to the start of the PT_NOTE data
258 if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) {
259 print_debug("failed to lseek to PT_NOTE data\n");
260 return false;
261 }
262
263 // Now process the PT_NOTE structures. Each one is preceded by
264 // an Elf{32/64}_Nhdr structure describing its type and size.
265 if ( (buf = (char*) malloc(size)) == NULL) {
266 print_debug("can't allocate memory for reading core notes\n");
267 goto err;
268 }
269
270 // read notes into buffer
271 if (read(ph->core->core_fd, buf, size) != size) {
272 print_debug("failed to read notes, core file must have been truncated\n");
273 goto err;
274 }
275
276 p = buf;
277 while (p < buf + size) {
278 ELF_NHDR* notep = (ELF_NHDR*) p;
279 char* descdata = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4);
280 print_debug("Note header with n_type = %d and n_descsz = %u\n",
281 notep->n_type, notep->n_descsz);
282
283 if (notep->n_type == NT_PRSTATUS) {
284 if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true) {
285 return false;
286 }
287 } else if (notep->n_type == NT_AUXV) {
288 // Get first segment from entry point
289 ELF_AUXV *auxv = (ELF_AUXV *)descdata;
290 while (auxv->a_type != AT_NULL) {
291 if (auxv->a_type == AT_ENTRY) {
292 // Set entry point address to address of dynamic section.
293 // We will adjust it in read_exec_segments().
294 ph->core->dynamic_addr = auxv->a_un.a_val;
295 break;
296 }
297 auxv++;
298 }
299 }
300 p = descdata + ROUNDUP(notep->n_descsz, 4);
301 }
302
303 free(buf);
304 return true;
305
306 err:
307 if (buf) free(buf);
308 return false;
309 }
310
311 // read all segments from core file
312 static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) {
313 int i = 0;
314 ELF_PHDR* phbuf = NULL;
315 ELF_PHDR* core_php = NULL;
316
317 if ((phbuf = read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL)
318 return false;
319
320 /*
321 * Now iterate through the program headers in the core file.
322 * We're interested in two types of Phdrs: PT_NOTE (which
323 * contains a set of saved /proc structures), and PT_LOAD (which
324 * represents a memory mapping from the process's address space).
325 *
326 * Difference b/w Solaris PT_NOTE and Linux/BSD PT_NOTE:
327 *
328 * In Solaris there are two PT_NOTE segments the first PT_NOTE (if present)
329 * contains /proc structs in the pre-2.6 unstructured /proc format. the last
330 * PT_NOTE has data in new /proc format.
331 *
332 * In Solaris, there is only one pstatus (process status). pstatus contains
333 * integer register set among other stuff. For each LWP, we have one lwpstatus
334 * entry that has integer regset for that LWP.
335 *
336 * Linux threads are actually 'clone'd processes. To support core analysis
337 * of "multithreaded" process, Linux creates more than one pstatus (called
338 * "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one
339 * "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular
340 * function "elf_core_dump".
341 */
342
343 for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) {
344 switch (core_php->p_type) {
345 case PT_NOTE:
346 if (core_handle_note(ph, core_php) != true) {
347 goto err;
348 }
349 break;
350
351 case PT_LOAD: {
352 if (core_php->p_filesz != 0) {
353 if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
354 core_php->p_vaddr, core_php->p_filesz, core_php->p_flags) == NULL) goto err;
355 }
356 break;
357 }
358 }
359
360 core_php++;
361 }
362
363 free(phbuf);
364 return true;
365 err:
366 free(phbuf);
367 return false;
368 }
369
370 // read segments of a shared object
371 static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) {
372 int i = 0;
373 ELF_PHDR* phbuf;
374 ELF_PHDR* lib_php = NULL;
375
376 int page_size = sysconf(_SC_PAGE_SIZE);
377
378 if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL) {
379 return false;
380 }
381
382 // we want to process only PT_LOAD segments that are not writable.
383 // i.e., text segments. The read/write/exec (data) segments would
384 // have been already added from core file segments.
385 for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) {
386 if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) {
387
388 uintptr_t target_vaddr = lib_php->p_vaddr + lib_base;
389 map_info *existing_map = core_lookup(ph, target_vaddr);
390
391 if (existing_map == NULL){
392 if (add_map_info(ph, lib_fd, lib_php->p_offset,
393 target_vaddr, lib_php->p_memsz, lib_php->p_flags) == NULL) {
394 goto err;
395 }
396 } else if (lib_php->p_flags != existing_map->flags) {
397 // Access flags for this memory region are different between the library
398 // and coredump. It might be caused by mprotect() call at runtime.
399 // We should respect the coredump.
400 continue;
401 } else {
402 // Read only segments in ELF should not be any different from PT_LOAD segments
403 // in the coredump.
404 // Also the first page of the ELF header might be included
405 // in the coredump (See JDK-7133122).
406 // Thus we need to replace the PT_LOAD segment with the library version.
407 //
408 // Coredump stores value of p_memsz elf field
409 // rounded up to page boundary.
410
411 if ((existing_map->memsz != page_size) &&
412 (existing_map->fd != lib_fd) &&
413 (ROUNDUP(existing_map->memsz, page_size) != ROUNDUP(lib_php->p_memsz, page_size))) {
414
415 print_debug("address conflict @ 0x%lx (existing map size = %ld, size = %ld, flags = %d)\n",
416 target_vaddr, existing_map->memsz, lib_php->p_memsz, lib_php->p_flags);
417 goto err;
418 }
419
420 /* replace PT_LOAD segment with library segment */
421 print_debug("overwrote with new address mapping (memsz %ld -> %ld)\n",
422 existing_map->memsz, ROUNDUP(lib_php->p_memsz, page_size));
423
424 existing_map->fd = lib_fd;
425 existing_map->offset = lib_php->p_offset;
426 existing_map->memsz = ROUNDUP(lib_php->p_memsz, page_size);
427 }
428 }
429
430 lib_php++;
431 }
432
433 free(phbuf);
434 return true;
435 err:
436 free(phbuf);
437 return false;
438 }
439
440 // process segments from interpreter (ld.so or ld-linux.so)
441 static bool read_interp_segments(struct ps_prochandle* ph) {
442 ELF_EHDR interp_ehdr;
443
444 if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) {
445 print_debug("interpreter is not a valid ELF file\n");
446 return false;
447 }
448
449 if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) {
450 print_debug("can't read segments of interpreter\n");
451 return false;
452 }
453
454 return true;
455 }
456
457 // process segments of a a.out
458 static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) {
459 int i = 0;
460 ELF_PHDR* phbuf = NULL;
461 ELF_PHDR* exec_php = NULL;
462
463 if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL) {
464 return false;
465 }
466
467 for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) {
468 switch (exec_php->p_type) {
469
470 // add mappings for PT_LOAD segments
471 case PT_LOAD: {
472 // add only non-writable segments of non-zero filesz
473 if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
474 if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz, exec_php->p_flags) == NULL) goto err;
475 }
476 break;
477 }
478
479 // read the interpreter and it's segments
480 case PT_INTERP: {
481 char interp_name[BUF_SIZE + 1];
482
483 // BUF_SIZE is PATH_MAX + NAME_MAX + 1.
484 if (exec_php->p_filesz > BUF_SIZE) {
485 goto err;
486 }
487 if (pread(ph->core->exec_fd, interp_name,
488 exec_php->p_filesz, exec_php->p_offset) != exec_php->p_filesz) {
489 print_debug("Unable to read in the ELF interpreter\n");
490 goto err;
491 }
492 interp_name[exec_php->p_filesz] = '\0';
493 print_debug("ELF interpreter %s\n", interp_name);
494 // read interpreter segments as well
495 if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) {
496 print_debug("can't open runtime loader\n");
497 goto err;
498 }
499 break;
500 }
501
502 // from PT_DYNAMIC we want to read address of first link_map addr
503 case PT_DYNAMIC: {
504 if (exec_ehdr->e_type == ET_EXEC) {
505 ph->core->dynamic_addr = exec_php->p_vaddr;
506 } else { // ET_DYN
507 // dynamic_addr has entry point of executable.
508 // Thus we should substract it.
509 ph->core->dynamic_addr += exec_php->p_vaddr - exec_ehdr->e_entry;
510 }
511 print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr);
512 break;
513 }
514
515 } // switch
516 exec_php++;
517 } // for
518
519 free(phbuf);
520 return true;
521 err:
522 free(phbuf);
523 return false;
524 }
525
526
527 #define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug, r_map)
528 #define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase)
529 #define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr)
530 #define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name)
531 #define LINK_MAP_LD_OFFSET offsetof(struct link_map, l_ld)
532 #define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next)
533
534 #define INVALID_LOAD_ADDRESS -1L
535 #define ZERO_LOAD_ADDRESS 0x0L
536
537 // Calculate the load address of shared library
538 // on prelink-enabled environment.
539 //
540 // In case of GDB, it would be calculated by offset of link_map.l_ld
541 // and the address of .dynamic section.
542 // See GDB implementation: lm_addr_check @ solib-svr4.c
543 static uintptr_t calc_prelinked_load_address(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* elf_ehdr, uintptr_t link_map_addr) {
544 ELF_PHDR *phbuf;
545 uintptr_t lib_ld;
546 uintptr_t lib_dyn_addr = 0L;
547 uintptr_t load_addr;
548 int i;
549
550 phbuf = read_program_header_table(lib_fd, elf_ehdr);
551 if (phbuf == NULL) {
552 print_debug("can't read program header of shared object\n");
553 return INVALID_LOAD_ADDRESS;
554 }
555
556 // Get the address of .dynamic section from shared library.
557 for (i = 0; i < elf_ehdr->e_phnum; i++) {
558 if (phbuf[i].p_type == PT_DYNAMIC) {
559 lib_dyn_addr = phbuf[i].p_vaddr;
560 break;
561 }
562 }
563
564 free(phbuf);
565
566 if (ps_pdread(ph, (psaddr_t)link_map_addr + LINK_MAP_LD_OFFSET,
567 &lib_ld, sizeof(uintptr_t)) != PS_OK) {
568 print_debug("can't read address of dynamic section in shared object\n");
569 return INVALID_LOAD_ADDRESS;
570 }
571
572 // Return the load address which is calculated by the address of .dynamic
573 // and link_map.l_ld .
574 load_addr = lib_ld - lib_dyn_addr;
575 print_debug("lib_ld = 0x%lx, lib_dyn_addr = 0x%lx -> lib_base_diff = 0x%lx\n", lib_ld, lib_dyn_addr, load_addr);
576 return load_addr;
577 }
578
579 // read shared library info from runtime linker's data structures.
580 // This work is done by librtlb_db in Solaris
581 static bool read_shared_lib_info(struct ps_prochandle* ph) {
582 uintptr_t addr = ph->core->dynamic_addr;
583 uintptr_t debug_base;
584 uintptr_t first_link_map_addr;
585 uintptr_t ld_base_addr;
586 uintptr_t link_map_addr;
587 uintptr_t lib_base_diff;
588 uintptr_t lib_base;
589 uintptr_t lib_name_addr;
590 char lib_name[BUF_SIZE];
591 ELF_DYN dyn;
592 ELF_EHDR elf_ehdr;
593 int lib_fd;
594
595 // _DYNAMIC has information of the form
596 // [tag] [data] [tag] [data] .....
597 // Both tag and data are pointer sized.
598 // We look for dynamic info with DT_DEBUG. This has shared object info.
599 // refer to struct r_debug in link.h
600
601 dyn.d_tag = DT_NULL;
602 while (dyn.d_tag != DT_DEBUG) {
603 if (ps_pdread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) {
604 print_debug("can't read debug info from _DYNAMIC\n");
605 return false;
606 }
607 addr += sizeof(ELF_DYN);
608 }
609
610 // we have got Dyn entry with DT_DEBUG
611 debug_base = dyn.d_un.d_ptr;
612 // at debug_base we have struct r_debug. This has first link map in r_map field
613 if (ps_pdread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET,
614 &first_link_map_addr, sizeof(uintptr_t)) != PS_OK) {
615 print_debug("can't read first link map address\n");
616 return false;
617 }
618
619 // read ld_base address from struct r_debug
620 if (ps_pdread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr,
621 sizeof(uintptr_t)) != PS_OK) {
622 print_debug("can't read ld base address\n");
623 return false;
624 }
625 ph->core->ld_base_addr = ld_base_addr;
626
627 print_debug("interpreter base address is 0x%lx\n", ld_base_addr);
628
629 // now read segments from interp (i.e ld.so or ld-linux.so or ld-elf.so)
630 if (read_interp_segments(ph) != true) {
631 return false;
632 }
633
634 // after adding interpreter (ld.so) mappings sort again
635 if (sort_map_array(ph) != true) {
636 return false;
637 }
638
639 print_debug("first link map is at 0x%lx\n", first_link_map_addr);
640
641 link_map_addr = first_link_map_addr;
642 while (link_map_addr != 0) {
643 // read library base address of the .so. Note that even though <sys/link.h> calls
644 // link_map->l_addr as "base address", this is * not * really base virtual
645 // address of the shared object. This is actually the difference b/w the virtual
646 // address mentioned in shared object and the actual virtual base where runtime
647 // linker loaded it. We use "base diff" in read_lib_segments call below.
648
649 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET,
650 &lib_base_diff, sizeof(uintptr_t)) != PS_OK) {
651 print_debug("can't read shared object base address diff\n");
652 return false;
653 }
654
655 // read address of the name
656 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET,
657 &lib_name_addr, sizeof(uintptr_t)) != PS_OK) {
658 print_debug("can't read address of shared object name\n");
659 return false;
660 }
661
662 // read name of the shared object
663 lib_name[0] = '\0';
664 if (lib_name_addr != 0 &&
665 read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) {
666 print_debug("can't read shared object name\n");
667 // don't let failure to read the name stop opening the file. If something is really wrong
668 // it will fail later.
669 }
670
671 if (lib_name[0] != '\0') {
672 // ignore empty lib names
673 lib_fd = pathmap_open(lib_name);
674
675 if (lib_fd < 0) {
676 print_debug("can't open shared object %s\n", lib_name);
677 // continue with other libraries...
678 } else {
679 if (read_elf_header(lib_fd, &elf_ehdr)) {
680 if (lib_base_diff == ZERO_LOAD_ADDRESS ) {
681 lib_base_diff = calc_prelinked_load_address(ph, lib_fd, &elf_ehdr, link_map_addr);
682 if (lib_base_diff == INVALID_LOAD_ADDRESS) {
683 close(lib_fd);
684 return false;
685 }
686 }
687
688 lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
689 print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
690 lib_name, lib_base, lib_base_diff);
691 // while adding library mappings we need to use "base difference".
692 if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) {
693 print_debug("can't read shared object's segments\n");
694 close(lib_fd);
695 return false;
696 }
697 add_lib_info_fd(ph, lib_name, lib_fd, lib_base);
698 // Map info is added for the library (lib_name) so
699 // we need to re-sort it before calling the p_pdread.
700 if (sort_map_array(ph) != true)
701 return false;
702 } else {
703 print_debug("can't read ELF header for shared object %s\n", lib_name);
704 close(lib_fd);
705 // continue with other libraries...
706 }
707 }
708 }
709
710 // read next link_map address
711 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET,
712 &link_map_addr, sizeof(uintptr_t)) != PS_OK) {
713 print_debug("can't read next link in link_map\n");
714 return false;
715 }
716 }
717
718 return true;
719 }
720
721 // the one and only one exposed stuff from this file
722 JNIEXPORT struct ps_prochandle* JNICALL
723 Pgrab_core(const char* exec_file, const char* core_file) {
724 ELF_EHDR core_ehdr;
725 ELF_EHDR exec_ehdr;
726 ELF_EHDR lib_ehdr;
727
728 struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle));
729 if (ph == NULL) {
730 print_debug("can't allocate ps_prochandle\n");
731 return NULL;
732 }
733
734 if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) {
735 free(ph);
736 print_debug("can't allocate ps_prochandle\n");
737 return NULL;
738 }
739
740 // initialize ph
741 ph->ops = &core_ops;
742 ph->core->core_fd = -1;
743 ph->core->exec_fd = -1;
744 ph->core->interp_fd = -1;
745
746 // open the core file
747 if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) {
748 print_debug("can't open core file\n");
749 goto err;
750 }
751
752 // read core file ELF header
753 if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) {
754 print_debug("core file is not a valid ELF ET_CORE file\n");
755 goto err;
756 }
757
758 if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) {
759 print_debug("can't open executable file\n");
760 goto err;
761 }
762
763 if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true ||
764 ((exec_ehdr.e_type != ET_EXEC) && (exec_ehdr.e_type != ET_DYN))) {
765 print_debug("executable file is not a valid ELF file\n");
766 goto err;
767 }
768
769 // process core file segments
770 if (read_core_segments(ph, &core_ehdr) != true) {
771 goto err;
772 }
773
774 // process exec file segments
775 if (read_exec_segments(ph, &exec_ehdr) != true) {
776 goto err;
777 }
778
779 // exec file is also treated like a shared object for symbol search
780 // FIXME: This is broken and ends up with a base address of 0. See JDK-8248876.
781 if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd,
782 (uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL) {
783 goto err;
784 }
785
786 // allocate and sort maps into map_array, we need to do this
787 // here because read_shared_lib_info needs to read from debuggee
788 // address space
789 if (sort_map_array(ph) != true) {
790 goto err;
791 }
792
793 if (read_shared_lib_info(ph) != true) {
794 goto err;
795 }
796
797 // sort again because we have added more mappings from shared objects
798 if (sort_map_array(ph) != true) {
799 goto err;
800 }
801
802 if (init_classsharing_workaround(ph) != true) {
803 goto err;
804 }
805
806 return ph;
807
808 err:
809 Prelease(ph);
810 return NULL;
811 }