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