Sat, 07 Nov 2020 10:30:02 +0800
Added tag mips-jdk8u275-b01 for changeset d3b4d62f391f
1 /*
2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
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"
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)
40 //----------------------------------------------------------------------
41 // ps_prochandle cleanup helper functions
43 // close all file descriptors
44 static void close_files(struct ps_prochandle* ph) {
45 lib_info* lib = NULL;
47 // close core file descriptor
48 if (ph->core->core_fd >= 0)
49 close(ph->core->core_fd);
51 // close exec file descriptor
52 if (ph->core->exec_fd >= 0)
53 close(ph->core->exec_fd);
55 // close interp file descriptor
56 if (ph->core->interp_fd >= 0)
57 close(ph->core->interp_fd);
59 // close class share archive file
60 if (ph->core->classes_jsa_fd >= 0)
61 close(ph->core->classes_jsa_fd);
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 }
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 }
83 if (ph->core->map_array) {
84 free(ph->core->map_array);
85 }
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 }
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 }
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 }
112 // initialize map
113 map->fd = fd;
114 map->offset = offset;
115 map->vaddr = vaddr;
116 map->memsz = memsz;
117 return map;
118 }
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 }
128 // add this to map list
129 map->next = ph->core->maps;
130 ph->core->maps = map;
131 ph->core->num_maps++;
133 return map;
134 }
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 }
145 map->next = ph->core->class_share_maps;
146 ph->core->class_share_maps = map;
147 return map;
148 }
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;
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 }
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 }
171 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
172 return (mp);
173 }
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 }
194 print_debug("can't locate map_info at 0x%lx\n", addr);
195 return (NULL);
196 }
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.
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.
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.
215 #define NUM_SHARED_MAPS 4
217 // Refer to FileMapInfo::_current_version in filemap.hpp
218 #define CURRENT_ARCHIVE_VERSION 1
220 struct FileMapHeader {
221 int _magic; // identify file type.
222 int _version; // (from enum, above.)
223 size_t _alignment; // how shared archive should be aligned
225 struct space_info {
226 int _file_offset; // sizeof(this) rounded to vm page size
227 char* _base; // copy-on-write base address
228 size_t _capacity; // for validity checking
229 size_t _used; // for setting space top on read
231 // 4991491 NOTICE These are C++ bool's in filemap.hpp and must match up with
232 // the C type matching the C++ bool type on any given platform.
233 // We assume the corresponding C type is char but licensees
234 // may need to adjust the type of these fields.
235 char _read_only; // read only space?
236 char _allow_exec; // executable code in space?
238 } _space[NUM_SHARED_MAPS];
240 // Ignore the rest of the FileMapHeader. We don't need those fields here.
241 };
243 static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
244 jboolean i;
245 if (ps_pdread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
246 *pvalue = i;
247 return true;
248 } else {
249 return false;
250 }
251 }
253 static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
254 uintptr_t uip;
255 if (ps_pdread(ph, (psaddr_t) addr, (char *)&uip, sizeof(uip)) == PS_OK) {
256 *pvalue = uip;
257 return true;
258 } else {
259 return false;
260 }
261 }
263 // used to read strings from debuggee
264 static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
265 size_t i = 0;
266 char c = ' ';
268 while (c != '\0') {
269 if (ps_pdread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK) {
270 return false;
271 }
272 if (i < size - 1) {
273 buf[i] = c;
274 } else {
275 // smaller buffer
276 return false;
277 }
278 i++; addr++;
279 }
281 buf[i] = '\0';
282 return true;
283 }
285 #define USE_SHARED_SPACES_SYM "UseSharedSpaces"
286 // mangled name of Arguments::SharedArchivePath
287 #define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
288 #define LIBJVM_NAME "/libjvm.so"
290 static bool init_classsharing_workaround(struct ps_prochandle* ph) {
291 lib_info* lib = ph->libs;
292 while (lib != NULL) {
293 // we are iterating over shared objects from the core dump. look for
294 // libjvm.so.
295 const char *jvm_name = 0;
296 if ((jvm_name = strstr(lib->name, LIBJVM_NAME)) != 0) {
297 char classes_jsa[PATH_MAX];
298 struct FileMapHeader header;
299 int fd = -1;
300 int m = 0;
301 size_t n = 0;
302 uintptr_t base = 0, useSharedSpacesAddr = 0;
303 uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
304 jboolean useSharedSpaces = 0;
305 map_info* mi = 0;
307 memset(classes_jsa, 0, sizeof(classes_jsa));
308 jvm_name = lib->name;
309 useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
310 if (useSharedSpacesAddr == 0) {
311 print_debug("can't lookup 'UseSharedSpaces' flag\n");
312 return false;
313 }
315 // Hotspot vm types are not exported to build this library. So
316 // using equivalent type jboolean to read the value of
317 // UseSharedSpaces which is same as hotspot type "bool".
318 if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
319 print_debug("can't read the value of 'UseSharedSpaces' flag\n");
320 return false;
321 }
323 if ((int)useSharedSpaces == 0) {
324 print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
325 return true;
326 }
328 sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
329 if (sharedArchivePathAddrAddr == 0) {
330 print_debug("can't lookup shared archive path symbol\n");
331 return false;
332 }
334 if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
335 print_debug("can't read shared archive path pointer\n");
336 return false;
337 }
339 if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
340 print_debug("can't read shared archive path value\n");
341 return false;
342 }
344 print_debug("looking for %s\n", classes_jsa);
345 // open the class sharing archive file
346 fd = pathmap_open(classes_jsa);
347 if (fd < 0) {
348 print_debug("can't open %s!\n", classes_jsa);
349 ph->core->classes_jsa_fd = -1;
350 return false;
351 } else {
352 print_debug("opened %s\n", classes_jsa);
353 }
355 // read FileMapHeader from the file
356 memset(&header, 0, sizeof(struct FileMapHeader));
357 if ((n = read(fd, &header, sizeof(struct FileMapHeader)))
358 != sizeof(struct FileMapHeader)) {
359 print_debug("can't read shared archive file map header from %s\n", classes_jsa);
360 close(fd);
361 return false;
362 }
364 // check file magic
365 if (header._magic != 0xf00baba2) {
366 print_debug("%s has bad shared archive file magic number 0x%x, expecing 0xf00baba2\n",
367 classes_jsa, header._magic);
368 close(fd);
369 return false;
370 }
372 // check version
373 if (header._version != CURRENT_ARCHIVE_VERSION) {
374 print_debug("%s has wrong shared archive file version %d, expecting %d\n",
375 classes_jsa, header._version, CURRENT_ARCHIVE_VERSION);
376 close(fd);
377 return false;
378 }
380 ph->core->classes_jsa_fd = fd;
381 // add read-only maps from classes.jsa to the list of maps
382 for (m = 0; m < NUM_SHARED_MAPS; m++) {
383 if (header._space[m]._read_only) {
384 base = (uintptr_t) header._space[m]._base;
385 // no need to worry about the fractional pages at-the-end.
386 // possible fractional pages are handled by core_read_data.
387 add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
388 base, (size_t) header._space[m]._used);
389 print_debug("added a share archive map at 0x%lx\n", base);
390 }
391 }
392 return true;
393 }
394 lib = lib->next;
395 }
396 return true;
397 }
400 //---------------------------------------------------------------------------
401 // functions to handle map_info
403 // Order mappings based on virtual address. We use this function as the
404 // callback for sorting the array of map_info pointers.
405 static int core_cmp_mapping(const void *lhsp, const void *rhsp)
406 {
407 const map_info *lhs = *((const map_info **)lhsp);
408 const map_info *rhs = *((const map_info **)rhsp);
410 if (lhs->vaddr == rhs->vaddr) {
411 return (0);
412 }
414 return (lhs->vaddr < rhs->vaddr ? -1 : 1);
415 }
417 // we sort map_info by starting virtual address so that we can do
418 // binary search to read from an address.
419 static bool sort_map_array(struct ps_prochandle* ph) {
420 size_t num_maps = ph->core->num_maps;
421 map_info* map = ph->core->maps;
422 int i = 0;
424 // allocate map_array
425 map_info** array;
426 if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) {
427 print_debug("can't allocate memory for map array\n");
428 return false;
429 }
431 // add maps to array
432 while (map) {
433 array[i] = map;
434 i++;
435 map = map->next;
436 }
438 // sort is called twice. If this is second time, clear map array
439 if (ph->core->map_array) {
440 free(ph->core->map_array);
441 }
443 ph->core->map_array = array;
444 // sort the map_info array by base virtual address.
445 qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*),
446 core_cmp_mapping);
448 // print map
449 if (is_debug()) {
450 int j = 0;
451 print_debug("---- sorted virtual address map ----\n");
452 for (j = 0; j < ph->core->num_maps; j++) {
453 print_debug("base = 0x%lx\tsize = %zu\n", ph->core->map_array[j]->vaddr,
454 ph->core->map_array[j]->memsz);
455 }
456 }
458 return true;
459 }
461 #ifndef MIN
462 #define MIN(x, y) (((x) < (y))? (x): (y))
463 #endif
465 static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
466 ssize_t resid = size;
467 int page_size=sysconf(_SC_PAGE_SIZE);
468 while (resid != 0) {
469 map_info *mp = core_lookup(ph, addr);
470 uintptr_t mapoff;
471 ssize_t len, rem;
472 off_t off;
473 int fd;
475 if (mp == NULL) {
476 break; /* No mapping for this address */
477 }
479 fd = mp->fd;
480 mapoff = addr - mp->vaddr;
481 len = MIN(resid, mp->memsz - mapoff);
482 off = mp->offset + mapoff;
484 if ((len = pread(fd, buf, len, off)) <= 0) {
485 break;
486 }
488 resid -= len;
489 addr += len;
490 buf = (char *)buf + len;
492 // mappings always start at page boundary. But, may end in fractional
493 // page. fill zeros for possible fractional page at the end of a mapping.
494 rem = mp->memsz % page_size;
495 if (rem > 0) {
496 rem = page_size - rem;
497 len = MIN(resid, rem);
498 resid -= len;
499 addr += len;
500 // we are not assuming 'buf' to be zero initialized.
501 memset(buf, 0, len);
502 buf += len;
503 }
504 }
506 if (resid) {
507 print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n",
508 size, addr, resid);
509 return false;
510 } else {
511 return true;
512 }
513 }
515 // null implementation for write
516 static bool core_write_data(struct ps_prochandle* ph,
517 uintptr_t addr, const char *buf , size_t size) {
518 return false;
519 }
521 static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id,
522 struct user_regs_struct* regs) {
523 // for core we have cached the lwp regs from NOTE section
524 thread_info* thr = ph->threads;
525 while (thr) {
526 if (thr->lwp_id == lwp_id) {
527 memcpy(regs, &thr->regs, sizeof(struct user_regs_struct));
528 return true;
529 }
530 thr = thr->next;
531 }
532 return false;
533 }
535 static ps_prochandle_ops core_ops = {
536 .release= core_release,
537 .p_pread= core_read_data,
538 .p_pwrite= core_write_data,
539 .get_lwp_regs= core_get_lwp_regs
540 };
542 // read regs and create thread from NT_PRSTATUS entries from core file
543 static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) {
544 // we have to read prstatus_t from buf
545 // assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t");
546 prstatus_t* prstat = (prstatus_t*) buf;
547 thread_info* newthr;
548 print_debug("got integer regset for lwp %d\n", prstat->pr_pid);
549 // we set pthread_t to -1 for core dump
550 if((newthr = add_thread_info(ph, (pthread_t) -1, prstat->pr_pid)) == NULL)
551 return false;
553 // copy regs
554 memcpy(&newthr->regs, prstat->pr_reg, sizeof(struct user_regs_struct));
556 if (is_debug()) {
557 print_debug("integer regset\n");
558 #ifdef i386
559 // print the regset
560 print_debug("\teax = 0x%x\n", newthr->regs.eax);
561 print_debug("\tebx = 0x%x\n", newthr->regs.ebx);
562 print_debug("\tecx = 0x%x\n", newthr->regs.ecx);
563 print_debug("\tedx = 0x%x\n", newthr->regs.edx);
564 print_debug("\tesp = 0x%x\n", newthr->regs.esp);
565 print_debug("\tebp = 0x%x\n", newthr->regs.ebp);
566 print_debug("\tesi = 0x%x\n", newthr->regs.esi);
567 print_debug("\tedi = 0x%x\n", newthr->regs.edi);
568 print_debug("\teip = 0x%x\n", newthr->regs.eip);
569 #endif
571 #if defined(amd64) || defined(x86_64)
572 // print the regset
573 print_debug("\tr15 = 0x%lx\n", newthr->regs.r15);
574 print_debug("\tr14 = 0x%lx\n", newthr->regs.r14);
575 print_debug("\tr13 = 0x%lx\n", newthr->regs.r13);
576 print_debug("\tr12 = 0x%lx\n", newthr->regs.r12);
577 print_debug("\trbp = 0x%lx\n", newthr->regs.rbp);
578 print_debug("\trbx = 0x%lx\n", newthr->regs.rbx);
579 print_debug("\tr11 = 0x%lx\n", newthr->regs.r11);
580 print_debug("\tr10 = 0x%lx\n", newthr->regs.r10);
581 print_debug("\tr9 = 0x%lx\n", newthr->regs.r9);
582 print_debug("\tr8 = 0x%lx\n", newthr->regs.r8);
583 print_debug("\trax = 0x%lx\n", newthr->regs.rax);
584 print_debug("\trcx = 0x%lx\n", newthr->regs.rcx);
585 print_debug("\trdx = 0x%lx\n", newthr->regs.rdx);
586 print_debug("\trsi = 0x%lx\n", newthr->regs.rsi);
587 print_debug("\trdi = 0x%lx\n", newthr->regs.rdi);
588 print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax);
589 print_debug("\trip = 0x%lx\n", newthr->regs.rip);
590 print_debug("\tcs = 0x%lx\n", newthr->regs.cs);
591 print_debug("\teflags = 0x%lx\n", newthr->regs.eflags);
592 print_debug("\trsp = 0x%lx\n", newthr->regs.rsp);
593 print_debug("\tss = 0x%lx\n", newthr->regs.ss);
594 print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base);
595 print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base);
596 print_debug("\tds = 0x%lx\n", newthr->regs.ds);
597 print_debug("\tes = 0x%lx\n", newthr->regs.es);
598 print_debug("\tfs = 0x%lx\n", newthr->regs.fs);
599 print_debug("\tgs = 0x%lx\n", newthr->regs.gs);
600 #endif
601 }
603 return true;
604 }
606 #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y))
608 // read NT_PRSTATUS entries from core NOTE segment
609 static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) {
610 char* buf = NULL;
611 char* p = NULL;
612 size_t size = note_phdr->p_filesz;
614 // we are interested in just prstatus entries. we will ignore the rest.
615 // Advance the seek pointer to the start of the PT_NOTE data
616 if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) {
617 print_debug("failed to lseek to PT_NOTE data\n");
618 return false;
619 }
621 // Now process the PT_NOTE structures. Each one is preceded by
622 // an Elf{32/64}_Nhdr structure describing its type and size.
623 if ( (buf = (char*) malloc(size)) == NULL) {
624 print_debug("can't allocate memory for reading core notes\n");
625 goto err;
626 }
628 // read notes into buffer
629 if (read(ph->core->core_fd, buf, size) != size) {
630 print_debug("failed to read notes, core file must have been truncated\n");
631 goto err;
632 }
634 p = buf;
635 while (p < buf + size) {
636 ELF_NHDR* notep = (ELF_NHDR*) p;
637 char* descdata = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4);
638 print_debug("Note header with n_type = %d and n_descsz = %u\n",
639 notep->n_type, notep->n_descsz);
641 if (notep->n_type == NT_PRSTATUS) {
642 if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true) {
643 return false;
644 }
645 } else if (notep->n_type == NT_AUXV) {
646 // Get first segment from entry point
647 ELF_AUXV *auxv = (ELF_AUXV *)descdata;
648 while (auxv->a_type != AT_NULL) {
649 if (auxv->a_type == AT_ENTRY) {
650 // Set entry point address to address of dynamic section.
651 // We will adjust it in read_exec_segments().
652 ph->core->dynamic_addr = auxv->a_un.a_val;
653 break;
654 }
655 auxv++;
656 }
657 }
658 p = descdata + ROUNDUP(notep->n_descsz, 4);
659 }
661 free(buf);
662 return true;
664 err:
665 if (buf) free(buf);
666 return false;
667 }
669 // read all segments from core file
670 static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) {
671 int i = 0;
672 ELF_PHDR* phbuf = NULL;
673 ELF_PHDR* core_php = NULL;
675 if ((phbuf = read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL)
676 return false;
678 /*
679 * Now iterate through the program headers in the core file.
680 * We're interested in two types of Phdrs: PT_NOTE (which
681 * contains a set of saved /proc structures), and PT_LOAD (which
682 * represents a memory mapping from the process's address space).
683 *
684 * Difference b/w Solaris PT_NOTE and Linux/BSD PT_NOTE:
685 *
686 * In Solaris there are two PT_NOTE segments the first PT_NOTE (if present)
687 * contains /proc structs in the pre-2.6 unstructured /proc format. the last
688 * PT_NOTE has data in new /proc format.
689 *
690 * In Solaris, there is only one pstatus (process status). pstatus contains
691 * integer register set among other stuff. For each LWP, we have one lwpstatus
692 * entry that has integer regset for that LWP.
693 *
694 * Linux threads are actually 'clone'd processes. To support core analysis
695 * of "multithreaded" process, Linux creates more than one pstatus (called
696 * "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one
697 * "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular
698 * function "elf_core_dump".
699 */
701 for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) {
702 switch (core_php->p_type) {
703 case PT_NOTE:
704 if (core_handle_note(ph, core_php) != true) {
705 goto err;
706 }
707 break;
709 case PT_LOAD: {
710 if (core_php->p_filesz != 0) {
711 if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
712 core_php->p_vaddr, core_php->p_filesz) == NULL) goto err;
713 }
714 break;
715 }
716 }
718 core_php++;
719 }
721 free(phbuf);
722 return true;
723 err:
724 free(phbuf);
725 return false;
726 }
728 // read segments of a shared object
729 static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) {
730 int i = 0;
731 ELF_PHDR* phbuf;
732 ELF_PHDR* lib_php = NULL;
734 int page_size = sysconf(_SC_PAGE_SIZE);
736 if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL) {
737 return false;
738 }
740 // we want to process only PT_LOAD segments that are not writable.
741 // i.e., text segments. The read/write/exec (data) segments would
742 // have been already added from core file segments.
743 for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) {
744 if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) {
746 uintptr_t target_vaddr = lib_php->p_vaddr + lib_base;
747 map_info *existing_map = core_lookup(ph, target_vaddr);
749 if (existing_map == NULL){
750 if (add_map_info(ph, lib_fd, lib_php->p_offset,
751 target_vaddr, lib_php->p_memsz) == NULL) {
752 goto err;
753 }
754 } else {
755 // Coredump stores value of p_memsz elf field
756 // rounded up to page boundary.
758 if ((existing_map->memsz != page_size) &&
759 (existing_map->fd != lib_fd) &&
760 (ROUNDUP(existing_map->memsz, page_size) != ROUNDUP(lib_php->p_memsz, page_size))) {
762 print_debug("address conflict @ 0x%lx (existing map size = %ld, size = %ld, flags = %d)\n",
763 target_vaddr, existing_map->memsz, lib_php->p_memsz, lib_php->p_flags);
764 goto err;
765 }
767 /* replace PT_LOAD segment with library segment */
768 print_debug("overwrote with new address mapping (memsz %ld -> %ld)\n",
769 existing_map->memsz, ROUNDUP(lib_php->p_memsz, page_size));
771 existing_map->fd = lib_fd;
772 existing_map->offset = lib_php->p_offset;
773 existing_map->memsz = ROUNDUP(lib_php->p_memsz, page_size);
774 }
775 }
777 lib_php++;
778 }
780 free(phbuf);
781 return true;
782 err:
783 free(phbuf);
784 return false;
785 }
787 // process segments from interpreter (ld.so or ld-linux.so)
788 static bool read_interp_segments(struct ps_prochandle* ph) {
789 ELF_EHDR interp_ehdr;
791 if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) {
792 print_debug("interpreter is not a valid ELF file\n");
793 return false;
794 }
796 if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) {
797 print_debug("can't read segments of interpreter\n");
798 return false;
799 }
801 return true;
802 }
804 // process segments of a a.out
805 static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) {
806 int i = 0;
807 ELF_PHDR* phbuf = NULL;
808 ELF_PHDR* exec_php = NULL;
810 if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL)
811 return false;
813 for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) {
814 switch (exec_php->p_type) {
816 // add mappings for PT_LOAD segments
817 case PT_LOAD: {
818 // add only non-writable segments of non-zero filesz
819 if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
820 if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err;
821 }
822 break;
823 }
825 // read the interpreter and it's segments
826 case PT_INTERP: {
827 char interp_name[BUF_SIZE];
829 pread(ph->core->exec_fd, interp_name, MIN(exec_php->p_filesz, BUF_SIZE), exec_php->p_offset);
830 print_debug("ELF interpreter %s\n", interp_name);
831 // read interpreter segments as well
832 if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) {
833 print_debug("can't open runtime loader\n");
834 goto err;
835 }
836 break;
837 }
839 // from PT_DYNAMIC we want to read address of first link_map addr
840 case PT_DYNAMIC: {
841 if (exec_ehdr->e_type == ET_EXEC) {
842 ph->core->dynamic_addr = exec_php->p_vaddr;
843 } else { // ET_DYN
844 // dynamic_addr has entry point of executable.
845 // Thus we should substract it.
846 ph->core->dynamic_addr += exec_php->p_vaddr - exec_ehdr->e_entry;
847 }
848 print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr);
849 break;
850 }
852 } // switch
853 exec_php++;
854 } // for
856 free(phbuf);
857 return true;
858 err:
859 free(phbuf);
860 return false;
861 }
864 #define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug, r_map)
865 #define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase)
866 #define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr)
867 #define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name)
868 #define LINK_MAP_LD_OFFSET offsetof(struct link_map, l_ld)
869 #define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next)
871 #define INVALID_LOAD_ADDRESS -1L
872 #define ZERO_LOAD_ADDRESS 0x0L
874 // Calculate the load address of shared library
875 // on prelink-enabled environment.
876 //
877 // In case of GDB, it would be calculated by offset of link_map.l_ld
878 // and the address of .dynamic section.
879 // See GDB implementation: lm_addr_check @ solib-svr4.c
880 static uintptr_t calc_prelinked_load_address(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* elf_ehdr, uintptr_t link_map_addr) {
881 ELF_PHDR *phbuf;
882 uintptr_t lib_ld;
883 uintptr_t lib_dyn_addr = 0L;
884 uintptr_t load_addr;
885 int i;
887 phbuf = read_program_header_table(lib_fd, elf_ehdr);
888 if (phbuf == NULL) {
889 print_debug("can't read program header of shared object\n");
890 return INVALID_LOAD_ADDRESS;
891 }
893 // Get the address of .dynamic section from shared library.
894 for (i = 0; i < elf_ehdr->e_phnum; i++) {
895 if (phbuf[i].p_type == PT_DYNAMIC) {
896 lib_dyn_addr = phbuf[i].p_vaddr;
897 break;
898 }
899 }
901 free(phbuf);
903 if (ps_pdread(ph, (psaddr_t)link_map_addr + LINK_MAP_LD_OFFSET,
904 &lib_ld, sizeof(uintptr_t)) != PS_OK) {
905 print_debug("can't read address of dynamic section in shared object\n");
906 return INVALID_LOAD_ADDRESS;
907 }
909 // Return the load address which is calculated by the address of .dynamic
910 // and link_map.l_ld .
911 load_addr = lib_ld - lib_dyn_addr;
912 print_debug("lib_ld = 0x%lx, lib_dyn_addr = 0x%lx -> lib_base_diff = 0x%lx\n", lib_ld, lib_dyn_addr, load_addr);
913 return load_addr;
914 }
916 // read shared library info from runtime linker's data structures.
917 // This work is done by librtlb_db in Solaris
918 static bool read_shared_lib_info(struct ps_prochandle* ph) {
919 uintptr_t addr = ph->core->dynamic_addr;
920 uintptr_t debug_base;
921 uintptr_t first_link_map_addr;
922 uintptr_t ld_base_addr;
923 uintptr_t link_map_addr;
924 uintptr_t lib_base_diff;
925 uintptr_t lib_base;
926 uintptr_t lib_name_addr;
927 char lib_name[BUF_SIZE];
928 ELF_DYN dyn;
929 ELF_EHDR elf_ehdr;
930 int lib_fd;
932 // _DYNAMIC has information of the form
933 // [tag] [data] [tag] [data] .....
934 // Both tag and data are pointer sized.
935 // We look for dynamic info with DT_DEBUG. This has shared object info.
936 // refer to struct r_debug in link.h
938 dyn.d_tag = DT_NULL;
939 while (dyn.d_tag != DT_DEBUG) {
940 if (ps_pdread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) {
941 print_debug("can't read debug info from _DYNAMIC\n");
942 return false;
943 }
944 addr += sizeof(ELF_DYN);
945 }
947 // we have got Dyn entry with DT_DEBUG
948 debug_base = dyn.d_un.d_ptr;
949 // at debug_base we have struct r_debug. This has first link map in r_map field
950 if (ps_pdread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET,
951 &first_link_map_addr, sizeof(uintptr_t)) != PS_OK) {
952 print_debug("can't read first link map address\n");
953 return false;
954 }
956 // read ld_base address from struct r_debug
957 if (ps_pdread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr,
958 sizeof(uintptr_t)) != PS_OK) {
959 print_debug("can't read ld base address\n");
960 return false;
961 }
962 ph->core->ld_base_addr = ld_base_addr;
964 print_debug("interpreter base address is 0x%lx\n", ld_base_addr);
966 // now read segments from interp (i.e ld.so or ld-linux.so or ld-elf.so)
967 if (read_interp_segments(ph) != true) {
968 return false;
969 }
971 // after adding interpreter (ld.so) mappings sort again
972 if (sort_map_array(ph) != true) {
973 return false;
974 }
976 print_debug("first link map is at 0x%lx\n", first_link_map_addr);
978 link_map_addr = first_link_map_addr;
979 while (link_map_addr != 0) {
980 // read library base address of the .so. Note that even though <sys/link.h> calls
981 // link_map->l_addr as "base address", this is * not * really base virtual
982 // address of the shared object. This is actually the difference b/w the virtual
983 // address mentioned in shared object and the actual virtual base where runtime
984 // linker loaded it. We use "base diff" in read_lib_segments call below.
986 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET,
987 &lib_base_diff, sizeof(uintptr_t)) != PS_OK) {
988 print_debug("can't read shared object base address diff\n");
989 return false;
990 }
992 // read address of the name
993 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET,
994 &lib_name_addr, sizeof(uintptr_t)) != PS_OK) {
995 print_debug("can't read address of shared object name\n");
996 return false;
997 }
999 // read name of the shared object
1000 lib_name[0] = '\0';
1001 if (lib_name_addr != 0 &&
1002 read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) {
1003 print_debug("can't read shared object name\n");
1004 // don't let failure to read the name stop opening the file. If something is really wrong
1005 // it will fail later.
1006 }
1008 if (lib_name[0] != '\0') {
1009 // ignore empty lib names
1010 lib_fd = pathmap_open(lib_name);
1012 if (lib_fd < 0) {
1013 print_debug("can't open shared object %s\n", lib_name);
1014 // continue with other libraries...
1015 } else {
1016 if (read_elf_header(lib_fd, &elf_ehdr)) {
1017 if (lib_base_diff == ZERO_LOAD_ADDRESS) {
1018 lib_base_diff = calc_prelinked_load_address(ph, lib_fd, &elf_ehdr, link_map_addr);
1019 if (lib_base_diff == INVALID_LOAD_ADDRESS) {
1020 close(lib_fd);
1021 return false;
1022 }
1023 }
1025 lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
1026 print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
1027 lib_name, lib_base, lib_base_diff);
1028 // while adding library mappings we need to use "base difference".
1029 if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) {
1030 print_debug("can't read shared object's segments\n");
1031 close(lib_fd);
1032 return false;
1033 }
1034 add_lib_info_fd(ph, lib_name, lib_fd, lib_base);
1035 // Map info is added for the library (lib_name) so
1036 // we need to re-sort it before calling the p_pdread.
1037 if (sort_map_array(ph) != true)
1038 return false;
1039 } else {
1040 print_debug("can't read ELF header for shared object %s\n", lib_name);
1041 close(lib_fd);
1042 // continue with other libraries...
1043 }
1044 }
1045 }
1047 // read next link_map address
1048 if (ps_pdread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET,
1049 &link_map_addr, sizeof(uintptr_t)) != PS_OK) {
1050 print_debug("can't read next link in link_map\n");
1051 return false;
1052 }
1053 }
1055 return true;
1056 }
1058 // the one and only one exposed stuff from this file
1059 struct ps_prochandle* Pgrab_core(const char* exec_file, const char* core_file) {
1060 ELF_EHDR core_ehdr;
1061 ELF_EHDR exec_ehdr;
1062 ELF_EHDR lib_ehdr;
1064 struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle));
1065 if (ph == NULL) {
1066 print_debug("can't allocate ps_prochandle\n");
1067 return NULL;
1068 }
1070 if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) {
1071 free(ph);
1072 print_debug("can't allocate ps_prochandle\n");
1073 return NULL;
1074 }
1076 // initialize ph
1077 ph->ops = &core_ops;
1078 ph->core->core_fd = -1;
1079 ph->core->exec_fd = -1;
1080 ph->core->interp_fd = -1;
1082 // open the core file
1083 if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) {
1084 print_debug("can't open core file\n");
1085 goto err;
1086 }
1088 // read core file ELF header
1089 if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) {
1090 print_debug("core file is not a valid ELF ET_CORE file\n");
1091 goto err;
1092 }
1094 if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) {
1095 print_debug("can't open executable file\n");
1096 goto err;
1097 }
1099 if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true ||
1100 ((exec_ehdr.e_type != ET_EXEC) && (exec_ehdr.e_type != ET_DYN))) {
1101 print_debug("executable file is not a valid ELF file\n");
1102 goto err;
1103 }
1105 // process core file segments
1106 if (read_core_segments(ph, &core_ehdr) != true) {
1107 goto err;
1108 }
1110 // process exec file segments
1111 if (read_exec_segments(ph, &exec_ehdr) != true) {
1112 goto err;
1113 }
1115 // exec file is also treated like a shared object for symbol search
1116 if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd,
1117 (uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL) {
1118 goto err;
1119 }
1121 // allocate and sort maps into map_array, we need to do this
1122 // here because read_shared_lib_info needs to read from debuggee
1123 // address space
1124 if (sort_map_array(ph) != true) {
1125 goto err;
1126 }
1128 if (read_shared_lib_info(ph) != true) {
1129 goto err;
1130 }
1132 // sort again because we have added more mappings from shared objects
1133 if (sort_map_array(ph) != true) {
1134 goto err;
1135 }
1137 if (init_classsharing_workaround(ph) != true) {
1138 goto err;
1139 }
1141 return ph;
1143 err:
1144 Prelease(ph);
1145 return NULL;
1146 }