1 /*
2 * Copyright (c) 2003, 2017, 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 #ifdef INCLUDE_SA_ATTACH
30 #include <thread_db.h>
31 #else
32 #include <dirent.h>
33 #endif
34 #include "libproc_impl.h"
35
36 #define SA_ALTROOT "SA_ALTROOT"
37
38 int pathmap_open(const char* name) {
39 static const char *alt_root = NULL;
40 static int alt_root_initialized = 0;
41
42 int fd;
43 char alt_path[PATH_MAX + 1], *alt_path_end;
44 const char *s;
45 int free_space;
46
47 if (!alt_root_initialized) {
48 alt_root_initialized = -1;
49 alt_root = getenv(SA_ALTROOT);
50 }
51
52 if (alt_root == NULL) {
53 return open(name, O_RDONLY);
54 }
55
56
57 if (strlen(alt_root) + strlen(name) > PATH_MAX) {
58 // Buffer too small.
59 return -1;
60 }
61
62 strncpy(alt_path, alt_root, PATH_MAX);
63 alt_path[PATH_MAX] = '\0';
64 alt_path_end = alt_path + strlen(alt_path);
65 free_space = PATH_MAX + 1 - (alt_path_end-alt_path);
66
67 // Strip path items one by one and try to open file with alt_root prepended.
68 s = name;
69 while (1) {
70 strncat(alt_path, s, free_space);
71 s += 1; // Skip /.
72
73 fd = open(alt_path, O_RDONLY);
74 if (fd >= 0) {
75 print_debug("path %s substituted for %s\n", alt_path, name);
76 return fd;
77 }
78
79 // Linker always put full path to solib to process, so we can rely
80 // on presence of /. If slash is not present, it means, that SOlib doesn't
81 // physically exist (e.g. linux-gate.so) and we fail opening it anyway
82 if ((s = strchr(s, '/')) == NULL) {
83 break;
84 }
85
86 // Cut off what we appended above.
87 *alt_path_end = '\0';
88 }
89
90 return -1;
91 }
92
93 static bool _libsaproc_debug;
94
95 void print_debug(const char* format,...) {
96 if (_libsaproc_debug) {
97 va_list alist;
98
99 va_start(alist, format);
100 fputs("libsaproc DEBUG: ", stderr);
101 vfprintf(stderr, format, alist);
102 va_end(alist);
103 }
104 }
105
106 void print_error(const char* format,...) {
107 va_list alist;
108 va_start(alist, format);
109 fputs("ERROR: ", stderr);
110 vfprintf(stderr, format, alist);
111 va_end(alist);
112 }
113
114 bool is_debug() {
115 return _libsaproc_debug;
116 }
117
118 // initialize libproc
119 bool init_libproc(bool debug) {
120 // init debug mode
121 _libsaproc_debug = debug;
122
123 #ifdef INCLUDE_SA_ATTACH
124 // initialize the thread_db library
125 if (td_init() != TD_OK) {
126 print_debug("libthread_db's td_init failed\n");
127 return false;
128 }
129 #endif
130
131 return true;
132 }
133
134 static void destroy_lib_info(struct ps_prochandle* ph) {
135 lib_info* lib = ph->libs;
136 while (lib) {
137 lib_info *next = lib->next;
138 if (lib->symtab) {
139 destroy_symtab(lib->symtab);
140 }
141 free(lib);
142 lib = next;
143 }
144 }
145
146 static void destroy_thread_info(struct ps_prochandle* ph) {
147 thread_info* thr = ph->threads;
148 while (thr) {
149 thread_info *next = thr->next;
150 free(thr);
151 thr = next;
152 }
153 }
154
155 // ps_prochandle cleanup
156
157 // ps_prochandle cleanup
158 void Prelease(struct ps_prochandle* ph) {
159 // do the "derived class" clean-up first
160 ph->ops->release(ph);
161 destroy_lib_info(ph);
162 destroy_thread_info(ph);
163 free(ph);
164 }
165
166 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
167 return add_lib_info_fd(ph, libname, -1, base);
168 }
169
170 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
171 lib_info* newlib;
172
173 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
174 print_debug("can't allocate memory for lib_info\n");
175 return NULL;
176 }
177
178 if (strlen(libname) >= sizeof(newlib->name)) {
179 print_debug("libname %s too long\n", libname);
180 free(newlib);
181 return NULL;
182 }
183 strcpy(newlib->name, libname);
184
185 newlib->base = base;
186
187 if (fd == -1) {
188 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
189 print_debug("can't open shared object %s\n", newlib->name);
190 free(newlib);
191 return NULL;
192 }
193 } else {
194 newlib->fd = fd;
195 }
196
197 // check whether we have got an ELF file. /proc/<pid>/map
198 // gives out all file mappings and not just shared objects
199 if (is_elf_file(newlib->fd) == false) {
200 close(newlib->fd);
201 free(newlib);
202 return NULL;
203 }
204
205 newlib->symtab = build_symtab(newlib->fd, libname);
206 if (newlib->symtab == NULL) {
207 print_debug("symbol table build failed for %s\n", newlib->name);
208 }
209
210 // even if symbol table building fails, we add the lib_info.
211 // This is because we may need to read from the ELF file for core file
212 // address read functionality. lookup_symbol checks for NULL symtab.
213 if (ph->libs) {
214 ph->lib_tail->next = newlib;
215 ph->lib_tail = newlib;
216 } else {
217 ph->libs = ph->lib_tail = newlib;
218 }
219 ph->num_libs++;
220
221 return newlib;
222 }
223
224 // lookup for a specific symbol
225 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name,
226 const char* sym_name) {
227 // ignore object_name. search in all libraries
228 // FIXME: what should we do with object_name?? The library names are obtained
229 // by parsing /proc/<pid>/maps, which may not be the same as object_name.
230 // What we need is a utility to map object_name to real file name, something
231 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
232 // now, we just ignore object_name and do a global search for the symbol.
233
234 lib_info* lib = ph->libs;
235 while (lib) {
236 if (lib->symtab) {
237 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
238 if (res) return res;
239 }
240 lib = lib->next;
241 }
242
243 print_debug("lookup failed for symbol '%s' in obj '%s'\n",
244 sym_name, object_name);
245 return (uintptr_t) NULL;
246 }
247
248
249 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
250 const char* res = NULL;
251 lib_info* lib = ph->libs;
252 while (lib) {
253 if (lib->symtab && addr >= lib->base) {
254 res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
255 if (res) return res;
256 }
257 lib = lib->next;
258 }
259 return NULL;
260 }
261
262 // add a thread to ps_prochandle
263 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {
264 thread_info* newthr;
265 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
266 print_debug("can't allocate memory for thread_info\n");
267 return NULL;
268 }
269
270 // initialize thread info
271 newthr->pthread_id = pthread_id;
272 newthr->lwp_id = lwp_id;
273
274 // add new thread to the list
275 newthr->next = ph->threads;
276 ph->threads = newthr;
277 ph->num_threads++;
278 return newthr;
279 }
280
281
282 #ifdef INCLUDE_SA_ATTACH
283 // struct used for client data from thread_db callback
284 struct thread_db_client_data {
285 struct ps_prochandle* ph;
286 thread_info_callback callback;
287 };
288
289 // callback function for libthread_db
290 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) {
291 struct thread_db_client_data* ptr = (struct thread_db_client_data*) data;
292 td_thrinfo_t ti;
293 td_err_e err;
294
295 memset(&ti, 0, sizeof(ti));
296 err = td_thr_get_info(th_p, &ti);
297 if (err != TD_OK) {
298 print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n");
299 return err;
300 }
301
302 print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid);
303
304 if (ptr->callback(ptr->ph, ti.ti_tid, ti.ti_lid) != true)
305 return TD_ERR;
306
307 return TD_OK;
308 }
309 #endif // INCLUDE_SA_ATTACH
310
311 // read thread_info using libthread_db or by iterating through the entries
312 // in /proc/<pid>/task/
313 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) {
314 #ifdef INCLUDE_SA_ATTACH
315 struct thread_db_client_data mydata;
316 td_thragent_t* thread_agent = NULL;
317 if (td_ta_new(ph, &thread_agent) != TD_OK) {
318 print_debug("can't create libthread_db agent\n");
319 return false;
320 }
321
322 mydata.ph = ph;
323 mydata.callback = cb;
324
325 // we use libthread_db iterator to iterate thru list of threads.
326 if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata,
327 TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
328 TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) {
329 td_ta_delete(thread_agent);
330 return false;
331 }
332
333 // delete thread agent
334 td_ta_delete(thread_agent);
335 #else
336 DIR *dir = NULL;
337 struct dirent *ent = NULL;
338 char taskpath[80];
339 pid_t pid = ph->pid;
340
341 // Find the lwpids to attach to by traversing the /proc/<pid>/task/ directory.
342 snprintf(taskpath, sizeof (taskpath), "/proc/%ld/task", (unsigned long)pid);
343 if ((dir = opendir(taskpath)) != NULL) {
344 while ((ent = readdir(dir)) != NULL) {
345 unsigned long lwp;
346
347 if ((lwp = strtoul(ent->d_name, NULL, 10)) != 0) {
348 // Create and add the thread info.
349 (*cb)(ph, 0, lwp);
350 }
351 }
352 } else {
353 print_debug("Could not open /proc/%ld/task.\n", (unsigned long)pid);
354 return false;
355 }
356
357 closedir(dir);
358 #endif
359 return true;
360 }
361
362 // get number of threads
363 int get_num_threads(struct ps_prochandle* ph) {
364 return ph->num_threads;
365 }
366
367 // get lwp_id of n'th thread
368 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
369 int count = 0;
370 thread_info* thr = ph->threads;
371 while (thr) {
372 if (count == index) {
373 return thr->lwp_id;
374 }
375 count++;
376 thr = thr->next;
377 }
378 return -1;
379 }
380
381 // get regs for a given lwp
382 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) {
383 return ph->ops->get_lwp_regs(ph, lwp_id, regs);
384 }
385
386 // get number of shared objects
387 int get_num_libs(struct ps_prochandle* ph) {
388 return ph->num_libs;
389 }
390
391 // get name of n'th solib
392 const char* get_lib_name(struct ps_prochandle* ph, int index) {
393 int count = 0;
394 lib_info* lib = ph->libs;
395 while (lib) {
396 if (count == index) {
397 return lib->name;
398 }
399 count++;
400 lib = lib->next;
401 }
402 return NULL;
403 }
404
405 // get base address of a lib
406 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
407 int count = 0;
408 lib_info* lib = ph->libs;
409 while (lib) {
410 if (count == index) {
411 return lib->base;
412 }
413 count++;
414 lib = lib->next;
415 }
416 return (uintptr_t)NULL;
417 }
418
419 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
420 lib_info *p = ph->libs;
421 while (p) {
422 if (strcmp(p->name, lib_name) == 0) {
423 return true;
424 }
425 p = p->next;
426 }
427 return false;
428 }
429
430 //--------------------------------------------------------------------------
431 // proc service functions
432
433 // get process id
434 pid_t ps_getpid(struct ps_prochandle *ph) {
435 return ph->pid;
436 }
437
438 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
439 // of the load object object_name in the target process identified by ph.
440 // It returns the symbol's value as an address in the target process in
441 // *sym_addr.
442
443 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
444 const char *sym_name, psaddr_t *sym_addr) {
445 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
446 return (*sym_addr ? PS_OK : PS_NOSYM);
447 }
448
449 // read "size" bytes info "buf" from address "addr"
450 ps_err_e ps_pdread(struct ps_prochandle *ph, psaddr_t addr,
451 void *buf, size_t size) {
452 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
453 }
454
455 // write "size" bytes of data to debuggee at address "addr"
456 ps_err_e ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr,
457 const void *buf, size_t size) {
458 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
459 }
460
461 // ------------------------------------------------------------------------
462 // Functions below this point are not yet implemented. They are here only
463 // to make the linker happy.
464
465 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
466 print_debug("ps_lsetfpregs not implemented\n");
467 return PS_OK;
468 }
469
470 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
471 print_debug("ps_lsetregs not implemented\n");
472 return PS_OK;
473 }
474
475 ps_err_e ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) {
476 print_debug("ps_lgetfpregs not implemented\n");
477 return PS_OK;
478 }
479
480 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
481 print_debug("ps_lgetfpregs not implemented\n");
482 return PS_OK;
483 }
484
485 // new libthread_db of NPTL seem to require this symbol
486 ps_err_e ps_get_thread_area() {
487 print_debug("ps_get_thread_area not implemented\n");
488 return PS_OK;
489 }