1 /*
2 * Copyright (c) 2003, 2019, 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 <sys/procfs.h>
30 #include "libproc_impl.h"
31 #include "proc_service.h"
32
33 #define SA_ALTROOT "SA_ALTROOT"
34
35 int pathmap_open(const char* name) {
36 static const char *alt_root = NULL;
37 static int alt_root_initialized = 0;
38
39 int fd;
40 char alt_path[PATH_MAX + 1], *alt_path_end;
41 const char *s;
42 int free_space;
43
44 if (!alt_root_initialized) {
45 alt_root_initialized = -1;
46 alt_root = getenv(SA_ALTROOT);
47 }
48
49 if (alt_root == NULL) {
50 return open(name, O_RDONLY);
51 }
52
53
54 if (strlen(alt_root) + strlen(name) > PATH_MAX) {
55 // Buffer too small.
56 return -1;
57 }
58
59 strncpy(alt_path, alt_root, PATH_MAX);
60 alt_path[PATH_MAX] = '\0';
61 alt_path_end = alt_path + strlen(alt_path);
62 free_space = PATH_MAX + 1 - (alt_path_end-alt_path);
63
64 // Strip path items one by one and try to open file with alt_root prepended.
65 s = name;
66 while (1) {
67 strncat(alt_path, s, free_space);
68 s += 1; // Skip /.
69
70 fd = open(alt_path, O_RDONLY);
71 if (fd >= 0) {
72 print_debug("path %s substituted for %s\n", alt_path, name);
73 return fd;
74 }
75
76 // Linker always put full path to solib to process, so we can rely
77 // on presence of /. If slash is not present, it means, that SOlib doesn't
78 // physically exist (e.g. linux-gate.so) and we fail opening it anyway
79 if ((s = strchr(s, '/')) == NULL) {
80 break;
81 }
82
83 // Cut off what we appended above.
84 *alt_path_end = '\0';
85 }
86
87 return -1;
88 }
89
90 static bool _libsaproc_debug;
91
92 void print_debug(const char* format,...) {
93 if (_libsaproc_debug) {
94 va_list alist;
95
96 va_start(alist, format);
97 fputs("libsaproc DEBUG: ", stderr);
98 vfprintf(stderr, format, alist);
99 va_end(alist);
100 }
101 }
102
103 void print_error(const char* format,...) {
104 va_list alist;
105 va_start(alist, format);
106 fputs("ERROR: ", stderr);
107 vfprintf(stderr, format, alist);
108 va_end(alist);
109 }
110
111 bool is_debug() {
112 return _libsaproc_debug;
113 }
114
115 // initialize libproc
116 JNIEXPORT bool JNICALL
117 init_libproc(bool debug) {
118 // init debug mode
119 _libsaproc_debug = debug;
120 return true;
121 }
122
123 static void destroy_lib_info(struct ps_prochandle* ph) {
124 lib_info* lib = ph->libs;
125 while (lib) {
126 lib_info *next = lib->next;
127 if (lib->symtab) {
128 destroy_symtab(lib->symtab);
129 }
130 free(lib);
131 lib = next;
132 }
133 }
134
135 static void destroy_thread_info(struct ps_prochandle* ph) {
136 thread_info* thr = ph->threads;
137 while (thr) {
138 thread_info *next = thr->next;
139 free(thr);
140 thr = next;
141 }
142 }
143
144 // ps_prochandle cleanup
145
146 // ps_prochandle cleanup
147 JNIEXPORT void JNICALL
148 Prelease(struct ps_prochandle* ph) {
149 // do the "derived class" clean-up first
150 ph->ops->release(ph);
151 destroy_lib_info(ph);
152 destroy_thread_info(ph);
153 free(ph);
154 }
155
156 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
157 return add_lib_info_fd(ph, libname, -1, base);
158 }
159
160 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
161 lib_info* newlib;
162
163 if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
164 print_debug("can't allocate memory for lib_info\n");
165 return NULL;
166 }
167
168 if (strlen(libname) >= sizeof(newlib->name)) {
169 print_debug("libname %s too long\n", libname);
170 free(newlib);
171 return NULL;
172 }
173 strcpy(newlib->name, libname);
174
175 newlib->base = base;
176
177 if (fd == -1) {
178 if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
179 print_debug("can't open shared object %s\n", newlib->name);
180 free(newlib);
181 return NULL;
182 }
183 } else {
184 newlib->fd = fd;
185 }
186
187 // check whether we have got an ELF file. /proc/<pid>/map
188 // gives out all file mappings and not just shared objects
189 if (is_elf_file(newlib->fd) == false) {
190 close(newlib->fd);
191 free(newlib);
192 return NULL;
193 }
194
195 newlib->symtab = build_symtab(newlib->fd, libname);
196 if (newlib->symtab == NULL) {
197 print_debug("symbol table build failed for %s\n", newlib->name);
198 }
199
200 // even if symbol table building fails, we add the lib_info.
201 // This is because we may need to read from the ELF file for core file
202 // address read functionality. lookup_symbol checks for NULL symtab.
203 if (ph->libs) {
204 ph->lib_tail->next = newlib;
205 ph->lib_tail = newlib;
206 } else {
207 ph->libs = ph->lib_tail = newlib;
208 }
209 ph->num_libs++;
210
211 return newlib;
212 }
213
214 // lookup for a specific symbol
215 uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name,
216 const char* sym_name) {
217 // ignore object_name. search in all libraries
218 // FIXME: what should we do with object_name?? The library names are obtained
219 // by parsing /proc/<pid>/maps, which may not be the same as object_name.
220 // What we need is a utility to map object_name to real file name, something
221 // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
222 // now, we just ignore object_name and do a global search for the symbol.
223
224 lib_info* lib = ph->libs;
225 while (lib) {
226 if (lib->symtab) {
227 uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
228 if (res) return res;
229 }
230 lib = lib->next;
231 }
232
233 print_debug("lookup failed for symbol '%s' in obj '%s'\n",
234 sym_name, object_name);
235 return (uintptr_t) NULL;
236 }
237
238
239 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
240 const char* res = NULL;
241 lib_info* lib = ph->libs;
242 while (lib) {
243 if (lib->symtab && addr >= lib->base) {
244 res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
245 if (res) return res;
246 }
247 lib = lib->next;
248 }
249 return NULL;
250 }
251
252 // add a thread to ps_prochandle
253 thread_info* add_thread_info(struct ps_prochandle* ph, lwpid_t lwp_id) {
254 thread_info* newthr;
255 if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
256 print_debug("can't allocate memory for thread_info\n");
257 return NULL;
258 }
259
260 // initialize thread info
261 newthr->lwp_id = lwp_id;
262
263 // add new thread to the list
264 newthr->next = ph->threads;
265 ph->threads = newthr;
266 ph->num_threads++;
267 return newthr;
268 }
269
270 void delete_thread_info(struct ps_prochandle* ph, thread_info* thr_to_be_removed) {
271 thread_info* current_thr = ph->threads;
272
273 if (thr_to_be_removed == ph->threads) {
274 ph->threads = ph->threads->next;
275 } else {
276 thread_info* previous_thr;
277 while (current_thr && current_thr != thr_to_be_removed) {
278 previous_thr = current_thr;
279 current_thr = current_thr->next;
280 }
281 if (current_thr == NULL) {
282 print_error("Could not find the thread to be removed");
283 return;
284 }
285 previous_thr->next = current_thr->next;
286 }
287 ph->num_threads--;
288 free(current_thr);
289 }
290
291 // get number of threads
292 int get_num_threads(struct ps_prochandle* ph) {
293 return ph->num_threads;
294 }
295
296 // get lwp_id of n'th thread
297 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
298 int count = 0;
299 thread_info* thr = ph->threads;
300 while (thr) {
301 if (count == index) {
302 return thr->lwp_id;
303 }
304 count++;
305 thr = thr->next;
306 }
307 return -1;
308 }
309
310 // get regs for a given lwp
311 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct user_regs_struct* regs) {
312 return ph->ops->get_lwp_regs(ph, lwp_id, regs);
313 }
314
315 // get number of shared objects
316 int get_num_libs(struct ps_prochandle* ph) {
317 return ph->num_libs;
318 }
319
320 // get name of n'th solib
321 const char* get_lib_name(struct ps_prochandle* ph, int index) {
322 int count = 0;
323 lib_info* lib = ph->libs;
324 while (lib) {
325 if (count == index) {
326 return lib->name;
327 }
328 count++;
329 lib = lib->next;
330 }
331 return NULL;
332 }
333
334 // get base address of a lib
335 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
336 int count = 0;
337 lib_info* lib = ph->libs;
338 while (lib) {
339 if (count == index) {
340 return lib->base;
341 }
342 count++;
343 lib = lib->next;
344 }
345 return (uintptr_t)NULL;
346 }
347
348 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
349 lib_info *p = ph->libs;
350 while (p) {
351 if (strcmp(p->name, lib_name) == 0) {
352 return true;
353 }
354 p = p->next;
355 }
356 return false;
357 }
358
359 //--------------------------------------------------------------------------
360 // proc service functions
361
362 // get process id
363 JNIEXPORT pid_t JNICALL
364 ps_getpid(struct ps_prochandle *ph) {
365 return ph->pid;
366 }
367
368 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
369 // of the load object object_name in the target process identified by ph.
370 // It returns the symbol's value as an address in the target process in
371 // *sym_addr.
372
373 JNIEXPORT ps_err_e JNICALL
374 ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
375 const char *sym_name, psaddr_t *sym_addr) {
376 *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
377 return (*sym_addr ? PS_OK : PS_NOSYM);
378 }
379
380 // read "size" bytes info "buf" from address "addr"
381 JNIEXPORT ps_err_e JNICALL
382 ps_pdread(struct ps_prochandle *ph, psaddr_t addr,
383 void *buf, size_t size) {
384 return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
385 }
386
387 // write "size" bytes of data to debuggee at address "addr"
388 JNIEXPORT ps_err_e JNICALL
389 ps_pdwrite(struct ps_prochandle *ph, psaddr_t addr,
390 const void *buf, size_t size) {
391 return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
392 }
393
394 // ------------------------------------------------------------------------
395 // Functions below this point are not yet implemented. They are here only
396 // to make the linker happy.
397
398 JNIEXPORT ps_err_e JNICALL
399 ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
400 print_debug("ps_lsetfpregs not implemented\n");
401 return PS_OK;
402 }
403
404 JNIEXPORT ps_err_e JNICALL
405 ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
406 print_debug("ps_lsetregs not implemented\n");
407 return PS_OK;
408 }
409
410 JNIEXPORT ps_err_e JNICALL
411 ps_lgetfpregs(struct ps_prochandle *ph, lwpid_t lid, prfpregset_t *fpregs) {
412 print_debug("ps_lgetfpregs not implemented\n");
413 return PS_OK;
414 }
415
416 JNIEXPORT ps_err_e JNICALL
417 ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
418 print_debug("ps_lgetfpregs not implemented\n");
419 return PS_OK;
420 }
421