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 #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 bool init_libproc(bool debug) {
116 // init debug mode
117 _libsaproc_debug = debug;
118
119 // initialize the thread_db library
120 if (td_init() != TD_OK) {
121 print_debug("libthread_db's td_init failed\n");
122 return false;
123 }
124
125 return true;
126 }
127
128 static void destroy_lib_info(struct ps_prochandle* ph) {
129 lib_info* lib = ph->libs;
130 while (lib) {
131 lib_info *next = lib->next;
132 if (lib->symtab) {
133 destroy_symtab(lib->symtab);
134 }
135 free(lib);
136 lib = next;
137 }
138 }
139
140 static void destroy_thread_info(struct ps_prochandle* ph) {
141 thread_info* thr = ph->threads;
142 while (thr) {
143 thread_info *next = thr->next;
144 free(thr);
145 thr = next;
146 }
147 }
148
149 // ps_prochandle cleanup
150
151 // ps_prochandle cleanup
152 void Prelease(struct ps_prochandle* ph) {
153 // do the "derived class" clean-up first
154 ph->ops->release(ph);
155 destroy_lib_info(ph);
156 destroy_thread_info(ph);
157 free(ph);
158 }
159
160 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
161 return add_lib_info_fd(ph, libname, -1, base);
162 }
163
164 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
165 lib_info* newlib;
166
167 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
168 print_debug("can't allocate memory for lib_info\n");
169 return NULL;
170 }
171
172 if (strlen(libname) >= sizeof(newlib->name)) {
173 print_debug("libname %s too long\n", libname);
174 free(newlib);
175 return NULL;
176 }
177 strcpy(newlib->name, libname);
178
179 newlib->base = base;
180
181 if (fd == -1) {
182 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
183 print_debug("can't open shared object %s\n", newlib->name);
184 free(newlib);
185 return NULL;
186 }
187 } else {
188 newlib->fd = fd;
189 }
190
191 // check whether we have got an ELF file. /proc/<pid>/map
192 // gives out all file mappings and not just shared objects
193 if (is_elf_file(newlib->fd) == false) {
194 close(newlib->fd);
195 free(newlib);
196 return NULL;
197 }
198
199 newlib->symtab = build_symtab(newlib->fd, libname);
200 if (newlib->symtab == NULL) {
201 print_debug("symbol table build failed for %s\n", newlib->name);
202 }
203
204 // even if symbol table building fails, we add the lib_info.
205 // This is because we may need to read from the ELF file for core file
206 // address read functionality. lookup_symbol checks for NULL symtab.
207 if (ph->libs) {
208 ph->lib_tail->next = newlib;
209 ph->lib_tail = newlib;
210 } else {
211 ph->libs = ph->lib_tail = newlib;
212 }
213 ph->num_libs++;
214
215 return newlib;
216 }
217
218 // lookup for a specific symbol
219 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name,
220 const char* sym_name) {
221 // ignore object_name. search in all libraries
222 // FIXME: what should we do with object_name?? The library names are obtained
223 // by parsing /proc/<pid>/maps, which may not be the same as object_name.
224 // What we need is a utility to map object_name to real file name, something
225 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
226 // now, we just ignore object_name and do a global search for the symbol.
227
228 lib_info* lib = ph->libs;
229 while (lib) {
230 if (lib->symtab) {
231 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
232 if (res) return res;
233 }
234 lib = lib->next;
235 }
236
237 print_debug("lookup failed for symbol '%s' in obj '%s'\n",
238 sym_name, object_name);
239 return (uintptr_t) NULL;
240 }
241
242
243 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
244 const char* res = NULL;
245 lib_info* lib = ph->libs;
246 while (lib) {
247 if (lib->symtab && addr >= lib->base) {
248 res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
249 if (res) return res;
250 }
251 lib = lib->next;
252 }
253 return NULL;
254 }
255
256 // add a thread to ps_prochandle
257 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {
258 thread_info* newthr;
259 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
260 print_debug("can't allocate memory for thread_info\n");
261 return NULL;
262 }
263
264 // initialize thread info
265 newthr->pthread_id = pthread_id;
266 newthr->lwp_id = lwp_id;
267
268 // add new thread to the list
269 newthr->next = ph->threads;
270 ph->threads = newthr;
271 ph->num_threads++;
272 return newthr;
273 }
274
275
276 // struct used for client data from thread_db callback
277 struct thread_db_client_data {
278 struct ps_prochandle* ph;
279 thread_info_callback callback;
280 };
281
282 // callback function for libthread_db
283 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) {
284 struct thread_db_client_data* ptr = (struct thread_db_client_data*) data;
285 td_thrinfo_t ti;
286 td_err_e err;
287
288 memset(&ti, 0, sizeof(ti));
289 err = td_thr_get_info(th_p, &ti);
290 if (err != TD_OK) {
291 print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n");
292 return err;
293 }
294
295 print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid);
296
297 if (ptr->callback(ptr->ph, ti.ti_tid, ti.ti_lid) != true)
298 return TD_ERR;
299
300 return TD_OK;
301 }
302
303 // read thread_info using libthread_db
304 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) {
305 struct thread_db_client_data mydata;
306 td_thragent_t* thread_agent = NULL;
307 if (td_ta_new(ph, &thread_agent) != TD_OK) {
308 print_debug("can't create libthread_db agent\n");
309 return false;
310 }
311
312 mydata.ph = ph;
313 mydata.callback = cb;
314
315 // we use libthread_db iterator to iterate thru list of threads.
316 if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata,
317 TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
318 TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) {
319 td_ta_delete(thread_agent);
320 return false;
321 }
322
323 // delete thread agent
324 td_ta_delete(thread_agent);
325 return true;
326 }
327
328
329 // get number of threads
330 int get_num_threads(struct ps_prochandle* ph) {
331 return ph->num_threads;
332 }
333
334 // get lwp_id of n'th thread
335 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
336 int count = 0;
337 thread_info* thr = ph->threads;
338 while (thr) {
339 if (count == index) {
340 return thr->lwp_id;
341 }
342 count++;
343 thr = thr->next;
344 }
345 return -1;
346 }
347
348 // get regs for a given lwp
349 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) {
350 return ph->ops->get_lwp_regs(ph, lwp_id, regs);
351 }
352
353 // get number of shared objects
354 int get_num_libs(struct ps_prochandle* ph) {
355 return ph->num_libs;
356 }
357
358 // get name of n'th solib
359 const char* get_lib_name(struct ps_prochandle* ph, int index) {
360 int count = 0;
361 lib_info* lib = ph->libs;
362 while (lib) {
363 if (count == index) {
364 return lib->name;
365 }
366 count++;
367 lib = lib->next;
368 }
369 return NULL;
370 }
371
372 // get base address of a lib
373 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
374 int count = 0;
375 lib_info* lib = ph->libs;
376 while (lib) {
377 if (count == index) {
378 return lib->base;
379 }
380 count++;
381 lib = lib->next;
382 }
383 return (uintptr_t)NULL;
384 }
385
386 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
387 lib_info *p = ph->libs;
388 while (p) {
389 if (strcmp(p->name, lib_name) == 0) {
390 return true;
391 }
392 p = p->next;
393 }
394 return false;
395 }
396
397 //--------------------------------------------------------------------------
398 // proc service functions
399
400 // get process id
401 pid_t ps_getpid(struct ps_prochandle *ph) {
402 return ph->pid;
403 }
404
405 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
406 // of the load object object_name in the target process identified by ph.
407 // It returns the symbol's value as an address in the target process in
408 // *sym_addr.
409
410 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
411 const char *sym_name, psaddr_t *sym_addr) {
412 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
413 return (*sym_addr ? PS_OK : PS_NOSYM);
414 }
415
416 // read "size" bytes info "buf" from address "addr"
417 ps_err_e ps_pdread(struct ps_prochandle *ph, psaddr_t addr,
418 void *buf, size_t size) {
419 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
420 }
421
422 // write "size" bytes of data to debuggee at address "addr"
423 ps_err_e ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr,
424 const void *buf, size_t size) {
425 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
426 }
427
428 // ------------------------------------------------------------------------
429 // Functions below this point are not yet implemented. They are here only
430 // to make the linker happy.
431
432 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
433 print_debug("ps_lsetfpregs not implemented\n");
434 return PS_OK;
435 }
436
437 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
438 print_debug("ps_lsetregs not implemented\n");
439 return PS_OK;
440 }
441
442 ps_err_e ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) {
443 print_debug("ps_lgetfpregs not implemented\n");
444 return PS_OK;
445 }
446
447 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
448 print_debug("ps_lgetfpregs not implemented\n");
449 return PS_OK;
450 }
451
452 // new libthread_db of NPTL seem to require this symbol
453 ps_err_e ps_get_thread_area() {
454 print_debug("ps_get_thread_area not implemented\n");
455 return PS_OK;
456 }