1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24 #include <stdarg.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <fcntl.h>
29 #include <thread_db.h>
30 #include "libproc_impl.h"
31
32 #define SA_ALTROOT "SA_ALTROOT"
33
34 int pathmap_open(const char* name) {
35 static const char *alt_root = NULL;
36 static int alt_root_initialized = 0;
37
38 int fd;
39 char alt_path[PATH_MAX + 1], *alt_path_end;
40 const char *s;
41 int free_space;
42
43 if (!alt_root_initialized) {
44 alt_root_initialized = -1;
45 alt_root = getenv(SA_ALTROOT);
46 }
47
48 if (alt_root == NULL) {
49 return open(name, O_RDONLY);
50 }
51
52
53 if (strlen(alt_root) + strlen(name) > PATH_MAX) {
54 // Buffer too small.
55 return -1;
56 }
57
58 strncpy(alt_path, alt_root, PATH_MAX);
59 alt_path[PATH_MAX] = '\0';
60 alt_path_end = alt_path + strlen(alt_path);
61 free_space = PATH_MAX + 1 - (alt_path_end-alt_path);
62
63 // Strip path items one by one and try to open file with alt_root prepended.
64 s = name;
65 while (1) {
66 strncat(alt_path, s, free_space);
67 s += 1; // Skip /.
68
69 fd = open(alt_path, O_RDONLY);
70 if (fd >= 0) {
71 print_debug("path %s substituted for %s\n", alt_path, name);
72 return fd;
73 }
74
75 // Linker always put full path to solib to process, so we can rely
76 // on presence of /. If slash is not present, it means, that SOlib doesn't
77 // physically exist (e.g. linux-gate.so) and we fail opening it anyway
78 if ((s = strchr(s, '/')) == NULL) {
79 break;
80 }
81
82 // Cut off what we appended above.
83 *alt_path_end = '\0';
84 }
85
86 return -1;
87 }
88
89 static bool _libsaproc_debug;
90
91 void print_debug(const char* format,...) {
92 if (_libsaproc_debug) {
93 va_list alist;
94
95 va_start(alist, format);
96 fputs("libsaproc DEBUG: ", stderr);
97 vfprintf(stderr, format, alist);
98 va_end(alist);
99 }
100 }
101
102 void print_error(const char* format,...) {
103 va_list alist;
104 va_start(alist, format);
105 fputs("ERROR: ", stderr);
106 vfprintf(stderr, format, alist);
107 va_end(alist);
108 }
109
110 bool is_debug() {
111 return _libsaproc_debug;
112 }
113
114 // initialize libproc
115 JNIEXPORT bool JNICALL
116 init_libproc(bool debug) {
117 // init debug mode
118 _libsaproc_debug = debug;
119
120 // initialize the thread_db library
121 if (td_init() != TD_OK) {
122 print_debug("libthread_db's td_init failed\n");
123 return false;
124 }
125
126 return true;
127 }
128
129 static void destroy_lib_info(struct ps_prochandle* ph) {
130 lib_info* lib = ph->libs;
131 while (lib) {
132 lib_info *next = lib->next;
133 if (lib->symtab) {
134 destroy_symtab(lib->symtab);
135 }
136 free(lib);
137 lib = next;
138 }
139 }
140
141 static void destroy_thread_info(struct ps_prochandle* ph) {
142 thread_info* thr = ph->threads;
143 while (thr) {
144 thread_info *next = thr->next;
145 free(thr);
146 thr = next;
147 }
148 }
149
150 // ps_prochandle cleanup
151
152 // ps_prochandle cleanup
153 JNIEXPORT void JNICALL
154 Prelease(struct ps_prochandle* ph) {
155 // do the "derived class" clean-up first
156 ph->ops->release(ph);
157 destroy_lib_info(ph);
158 destroy_thread_info(ph);
159 free(ph);
160 }
161
162 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
163 return add_lib_info_fd(ph, libname, -1, base);
164 }
165
166 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
167 lib_info* newlib;
168
169 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
170 print_debug("can't allocate memory for lib_info\n");
171 return NULL;
172 }
173
174 if (strlen(libname) >= sizeof(newlib->name)) {
175 print_debug("libname %s too long\n", libname);
176 free(newlib);
177 return NULL;
178 }
179 strcpy(newlib->name, libname);
180
181 newlib->base = base;
182
183 if (fd == -1) {
184 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
185 print_debug("can't open shared object %s\n", newlib->name);
186 free(newlib);
187 return NULL;
188 }
189 } else {
190 newlib->fd = fd;
191 }
192
193 // check whether we have got an ELF file. /proc/<pid>/map
194 // gives out all file mappings and not just shared objects
195 if (is_elf_file(newlib->fd) == false) {
196 close(newlib->fd);
197 free(newlib);
198 return NULL;
199 }
200
201 newlib->symtab = build_symtab(newlib->fd, libname);
202 if (newlib->symtab == NULL) {
203 print_debug("symbol table build failed for %s\n", newlib->name);
204 }
205
206 // even if symbol table building fails, we add the lib_info.
207 // This is because we may need to read from the ELF file for core file
208 // address read functionality. lookup_symbol checks for NULL symtab.
209 if (ph->libs) {
210 ph->lib_tail->next = newlib;
211 ph->lib_tail = newlib;
212 } else {
213 ph->libs = ph->lib_tail = newlib;
214 }
215 ph->num_libs++;
216
217 return newlib;
218 }
219
220 // lookup for a specific symbol
221 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name,
222 const char* sym_name) {
223 // ignore object_name. search in all libraries
224 // FIXME: what should we do with object_name?? The library names are obtained
225 // by parsing /proc/<pid>/maps, which may not be the same as object_name.
226 // What we need is a utility to map object_name to real file name, something
227 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
228 // now, we just ignore object_name and do a global search for the symbol.
229
230 lib_info* lib = ph->libs;
231 while (lib) {
232 if (lib->symtab) {
233 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
234 if (res) return res;
235 }
236 lib = lib->next;
237 }
238
239 print_debug("lookup failed for symbol '%s' in obj '%s'\n",
240 sym_name, object_name);
241 return (uintptr_t) NULL;
242 }
243
244
245 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
246 const char* res = NULL;
247 lib_info* lib = ph->libs;
248 while (lib) {
249 if (lib->symtab && addr >= lib->base) {
250 res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
251 if (res) return res;
252 }
253 lib = lib->next;
254 }
255 return NULL;
256 }
257
258 // add a thread to ps_prochandle
259 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {
260 thread_info* newthr;
261 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
262 print_debug("can't allocate memory for thread_info\n");
263 return NULL;
264 }
265
266 // initialize thread info
267 newthr->pthread_id = pthread_id;
268 newthr->lwp_id = lwp_id;
269
270 // add new thread to the list
271 newthr->next = ph->threads;
272 ph->threads = newthr;
273 ph->num_threads++;
274 return newthr;
275 }
276
277
278 // struct used for client data from thread_db callback
279 struct thread_db_client_data {
280 struct ps_prochandle* ph;
281 thread_info_callback callback;
282 };
283
284 // callback function for libthread_db
285 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) {
286 struct thread_db_client_data* ptr = (struct thread_db_client_data*) data;
287 td_thrinfo_t ti;
288 td_err_e err;
289
290 memset(&ti, 0, sizeof(ti));
291 err = td_thr_get_info(th_p, &ti);
292 if (err != TD_OK) {
293 print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n");
294 return err;
295 }
296
297 print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid);
298
299 if (ptr->callback(ptr->ph, ti.ti_tid, ti.ti_lid) != true)
300 return TD_ERR;
301
302 return TD_OK;
303 }
304
305 // read thread_info using libthread_db
306 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) {
307 struct thread_db_client_data mydata;
308 td_thragent_t* thread_agent = NULL;
309 if (td_ta_new(ph, &thread_agent) != TD_OK) {
310 print_debug("can't create libthread_db agent\n");
311 return false;
312 }
313
314 mydata.ph = ph;
315 mydata.callback = cb;
316
317 // we use libthread_db iterator to iterate thru list of threads.
318 if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata,
319 TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
320 TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) {
321 td_ta_delete(thread_agent);
322 return false;
323 }
324
325 // delete thread agent
326 td_ta_delete(thread_agent);
327 return true;
328 }
329
330
331 // get number of threads
332 int get_num_threads(struct ps_prochandle* ph) {
333 return ph->num_threads;
334 }
335
336 // get lwp_id of n'th thread
337 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
338 int count = 0;
339 thread_info* thr = ph->threads;
340 while (thr) {
341 if (count == index) {
342 return thr->lwp_id;
343 }
344 count++;
345 thr = thr->next;
346 }
347 return -1;
348 }
349
350 // get regs for a given lwp
351 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) {
352 return ph->ops->get_lwp_regs(ph, lwp_id, regs);
353 }
354
355 // get number of shared objects
356 int get_num_libs(struct ps_prochandle* ph) {
357 return ph->num_libs;
358 }
359
360 // get name of n'th solib
361 const char* get_lib_name(struct ps_prochandle* ph, int index) {
362 int count = 0;
363 lib_info* lib = ph->libs;
364 while (lib) {
365 if (count == index) {
366 return lib->name;
367 }
368 count++;
369 lib = lib->next;
370 }
371 return NULL;
372 }
373
374 // get base address of a lib
375 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
376 int count = 0;
377 lib_info* lib = ph->libs;
378 while (lib) {
379 if (count == index) {
380 return lib->base;
381 }
382 count++;
383 lib = lib->next;
384 }
385 return (uintptr_t)NULL;
386 }
387
388 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
389 lib_info *p = ph->libs;
390 while (p) {
391 if (strcmp(p->name, lib_name) == 0) {
392 return true;
393 }
394 p = p->next;
395 }
396 return false;
397 }
398
399 //--------------------------------------------------------------------------
400 // proc service functions
401
402 // get process id
403 JNIEXPORT pid_t JNICALL
404 ps_getpid(struct ps_prochandle *ph) {
405 return ph->pid;
406 }
407
408 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
409 // of the load object object_name in the target process identified by ph.
410 // It returns the symbol's value as an address in the target process in
411 // *sym_addr.
412
413 JNIEXPORT ps_err_e JNICALL
414 ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
415 const char *sym_name, psaddr_t *sym_addr) {
416 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
417 return (*sym_addr ? PS_OK : PS_NOSYM);
418 }
419
420 // read "size" bytes info "buf" from address "addr"
421 JNIEXPORT ps_err_e JNICALL
422 ps_pdread(struct ps_prochandle *ph, psaddr_t addr,
423 void *buf, size_t size) {
424 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
425 }
426
427 // write "size" bytes of data to debuggee at address "addr"
428 JNIEXPORT ps_err_e JNICALL
429 ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr,
430 const void *buf, size_t size) {
431 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
432 }
433
434 // ------------------------------------------------------------------------
435 // Functions below this point are not yet implemented. They are here only
436 // to make the linker happy.
437
438 JNIEXPORT ps_err_e JNICALL
439 ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
440 print_debug("ps_lsetfpregs not implemented\n");
441 return PS_OK;
442 }
443
444 JNIEXPORT ps_err_e JNICALL
445 ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
446 print_debug("ps_lsetregs not implemented\n");
447 return PS_OK;
448 }
449
450 JNIEXPORT ps_err_e JNICALL
451 ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) {
452 print_debug("ps_lgetfpregs not implemented\n");
453 return PS_OK;
454 }
455
456 JNIEXPORT ps_err_e JNICALL
457 ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
458 print_debug("ps_lgetfpregs not implemented\n");
459 return PS_OK;
460 }
461
462 // new libthread_db of NPTL seem to require this symbol
463 JNIEXPORT ps_err_e JNICALL
464 ps_get_thread_area() {
465 print_debug("ps_get_thread_area not implemented\n");
466 return PS_OK;
467 }