Mercurial > hg > graal-jvmci-8
annotate agent/src/os/linux/ps_proc.c @ 22838:7e2e246df4e9
8069030: support new PTRACE_GETREGSET
Summary: use PTRACE_GETREGSET if other options are not available
Reviewed-by: sla, dholmes
author | dlong |
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date | Mon, 02 Feb 2015 23:26:33 -0500 |
parents | f2512d89ad0c |
children | d06b64fc150f |
rev | line source |
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0 | 1 /* |
8058 | 2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 #include <stdio.h> | |
26 #include <stdlib.h> | |
27 #include <string.h> | |
8058 | 28 #include <signal.h> |
0 | 29 #include <errno.h> |
22838 | 30 #include <elf.h> |
12329 | 31 #include <sys/types.h> |
32 #include <sys/wait.h> | |
0 | 33 #include <sys/ptrace.h> |
22838 | 34 #include <sys/uio.h> |
0 | 35 #include "libproc_impl.h" |
36 | |
37 #if defined(x86_64) && !defined(amd64) | |
38 #define amd64 1 | |
39 #endif | |
40 | |
41 #ifndef __WALL | |
42 #define __WALL 0x40000000 // Copied from /usr/include/linux/wait.h | |
43 #endif | |
44 | |
45 // This file has the libproc implementation specific to live process | |
46 // For core files, refer to ps_core.c | |
47 | |
48 static inline uintptr_t align(uintptr_t ptr, size_t size) { | |
49 return (ptr & ~(size - 1)); | |
50 } | |
51 | |
52 // --------------------------------------------- | |
53 // ptrace functions | |
54 // --------------------------------------------- | |
55 | |
56 // read "size" bytes of data from "addr" within the target process. | |
57 // unlike the standard ptrace() function, process_read_data() can handle | |
58 // unaligned address - alignment check, if required, should be done | |
59 // before calling process_read_data. | |
60 | |
61 static bool process_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) { | |
62 long rslt; | |
63 size_t i, words; | |
64 uintptr_t end_addr = addr + size; | |
65 uintptr_t aligned_addr = align(addr, sizeof(long)); | |
66 | |
67 if (aligned_addr != addr) { | |
68 char *ptr = (char *)&rslt; | |
69 errno = 0; | |
70 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
71 if (errno) { | |
72 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
73 return false; | |
74 } | |
75 for (; aligned_addr != addr; aligned_addr++, ptr++); | |
76 for (; ((intptr_t)aligned_addr % sizeof(long)) && aligned_addr < end_addr; | |
77 aligned_addr++) | |
78 *(buf++) = *(ptr++); | |
79 } | |
80 | |
81 words = (end_addr - aligned_addr) / sizeof(long); | |
82 | |
83 // assert((intptr_t)aligned_addr % sizeof(long) == 0); | |
84 for (i = 0; i < words; i++) { | |
85 errno = 0; | |
86 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
87 if (errno) { | |
88 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
89 return false; | |
90 } | |
91 *(long *)buf = rslt; | |
92 buf += sizeof(long); | |
93 aligned_addr += sizeof(long); | |
94 } | |
95 | |
96 if (aligned_addr != end_addr) { | |
97 char *ptr = (char *)&rslt; | |
98 errno = 0; | |
99 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
100 if (errno) { | |
101 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
102 return false; | |
103 } | |
104 for (; aligned_addr != end_addr; aligned_addr++) | |
105 *(buf++) = *(ptr++); | |
106 } | |
107 return true; | |
108 } | |
109 | |
110 // null implementation for write | |
111 static bool process_write_data(struct ps_prochandle* ph, | |
112 uintptr_t addr, const char *buf , size_t size) { | |
113 return false; | |
114 } | |
115 | |
116 // "user" should be a pointer to a user_regs_struct | |
117 static bool process_get_lwp_regs(struct ps_prochandle* ph, pid_t pid, struct user_regs_struct *user) { | |
118 // we have already attached to all thread 'pid's, just use ptrace call | |
119 // to get regset now. Note that we don't cache regset upfront for processes. | |
120 // Linux on x86 and sparc are different. On x86 ptrace(PTRACE_GETREGS, ...) | |
121 // uses pointer from 4th argument and ignores 3rd argument. On sparc it uses | |
122 // pointer from 3rd argument and ignores 4th argument | |
123 #if defined(sparc) || defined(sparcv9) | |
124 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, addr, data) | |
125 #else | |
126 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, data, addr) | |
127 #endif | |
128 | |
1990 | 129 #if defined(_LP64) && defined(PTRACE_GETREGS64) |
0 | 130 #define PTRACE_GETREGS_REQ PTRACE_GETREGS64 |
1990 | 131 #elif defined(PTRACE_GETREGS) |
132 #define PTRACE_GETREGS_REQ PTRACE_GETREGS | |
133 #elif defined(PT_GETREGS) | |
134 #define PTRACE_GETREGS_REQ PT_GETREGS | |
0 | 135 #endif |
136 | |
137 #ifdef PTRACE_GETREGS_REQ | |
138 if (ptrace_getregs(PTRACE_GETREGS_REQ, pid, user, NULL) < 0) { | |
139 print_debug("ptrace(PTRACE_GETREGS, ...) failed for lwp %d\n", pid); | |
140 return false; | |
141 } | |
142 return true; | |
22838 | 143 #elif defined(PTRACE_GETREGSET) |
144 struct iovec iov; | |
145 iov.iov_base = user; | |
146 iov.iov_len = sizeof(*user); | |
147 if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, (void*) &iov) < 0) { | |
148 print_debug("ptrace(PTRACE_GETREGSET, ...) failed for lwp %d\n", pid); | |
149 return false; | |
150 } | |
151 return true; | |
0 | 152 #else |
153 print_debug("ptrace(PTRACE_GETREGS, ...) not supported\n"); | |
154 return false; | |
155 #endif | |
156 | |
157 } | |
158 | |
8058 | 159 static bool ptrace_continue(pid_t pid, int signal) { |
160 // pass the signal to the process so we don't swallow it | |
161 if (ptrace(PTRACE_CONT, pid, NULL, signal) < 0) { | |
162 print_debug("ptrace(PTRACE_CONT, ..) failed for %d\n", pid); | |
163 return false; | |
164 } | |
165 return true; | |
166 } | |
167 | |
168 // waits until the ATTACH has stopped the process | |
169 // by signal SIGSTOP | |
170 static bool ptrace_waitpid(pid_t pid) { | |
171 int ret; | |
172 int status; | |
173 while (true) { | |
174 // Wait for debuggee to stop. | |
175 ret = waitpid(pid, &status, 0); | |
176 if (ret == -1 && errno == ECHILD) { | |
177 // try cloned process. | |
178 ret = waitpid(pid, &status, __WALL); | |
179 } | |
180 if (ret >= 0) { | |
181 if (WIFSTOPPED(status)) { | |
182 // Any signal will stop the thread, make sure it is SIGSTOP. Otherwise SIGSTOP | |
183 // will still be pending and delivered when the process is DETACHED and the process | |
184 // will go to sleep. | |
185 if (WSTOPSIG(status) == SIGSTOP) { | |
186 // Debuggee stopped by SIGSTOP. | |
187 return true; | |
188 } | |
189 if (!ptrace_continue(pid, WSTOPSIG(status))) { | |
190 print_error("Failed to correctly attach to VM. VM might HANG! [PTRACE_CONT failed, stopped by %d]\n", WSTOPSIG(status)); | |
191 return false; | |
192 } | |
193 } else { | |
194 print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status); | |
195 return false; | |
196 } | |
197 } else { | |
198 switch (errno) { | |
199 case EINTR: | |
200 continue; | |
201 break; | |
202 case ECHILD: | |
203 print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid); | |
204 break; | |
205 case EINVAL: | |
206 print_debug("waitpid() failed. Invalid options argument.\n"); | |
207 break; | |
208 default: | |
209 print_debug("waitpid() failed. Unexpected error %d\n",errno); | |
210 break; | |
211 } | |
212 return false; | |
213 } | |
214 } | |
215 } | |
216 | |
0 | 217 // attach to a process/thread specified by "pid" |
218 static bool ptrace_attach(pid_t pid) { | |
219 if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) { | |
220 print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid); | |
221 return false; | |
222 } else { | |
8058 | 223 return ptrace_waitpid(pid); |
0 | 224 } |
225 } | |
226 | |
227 // ------------------------------------------------------- | |
228 // functions for obtaining library information | |
229 // ------------------------------------------------------- | |
230 | |
231 /* | |
232 * splits a string _str_ into substrings with delimiter _delim_ by replacing old * delimiters with _new_delim_ (ideally, '\0'). the address of each substring | |
233 * is stored in array _ptrs_ as the return value. the maximum capacity of _ptrs_ * array is specified by parameter _n_. | |
234 * RETURN VALUE: total number of substrings (always <= _n_) | |
235 * NOTE: string _str_ is modified if _delim_!=_new_delim_ | |
236 */ | |
237 static int split_n_str(char * str, int n, char ** ptrs, char delim, char new_delim) | |
238 { | |
239 int i; | |
240 for(i = 0; i < n; i++) ptrs[i] = NULL; | |
241 if (str == NULL || n < 1 ) return 0; | |
242 | |
243 i = 0; | |
244 | |
245 // skipping leading blanks | |
246 while(*str&&*str==delim) str++; | |
247 | |
248 while(*str&&i<n){ | |
249 ptrs[i++] = str; | |
250 while(*str&&*str!=delim) str++; | |
251 while(*str&&*str==delim) *(str++) = new_delim; | |
252 } | |
253 | |
254 return i; | |
255 } | |
256 | |
257 /* | |
258 * fgets without storing '\n' at the end of the string | |
259 */ | |
260 static char * fgets_no_cr(char * buf, int n, FILE *fp) | |
261 { | |
262 char * rslt = fgets(buf, n, fp); | |
263 if (rslt && buf && *buf){ | |
264 char *p = strchr(buf, '\0'); | |
265 if (*--p=='\n') *p='\0'; | |
266 } | |
267 return rslt; | |
268 } | |
269 | |
270 // callback for read_thread_info | |
271 static bool add_new_thread(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) { | |
272 return add_thread_info(ph, pthread_id, lwp_id) != NULL; | |
273 } | |
274 | |
275 static bool read_lib_info(struct ps_prochandle* ph) { | |
276 char fname[32]; | |
277 char buf[256]; | |
278 FILE *fp = NULL; | |
279 | |
280 sprintf(fname, "/proc/%d/maps", ph->pid); | |
281 fp = fopen(fname, "r"); | |
282 if (fp == NULL) { | |
283 print_debug("can't open /proc/%d/maps file\n", ph->pid); | |
284 return false; | |
285 } | |
286 | |
287 while(fgets_no_cr(buf, 256, fp)){ | |
288 char * word[6]; | |
289 int nwords = split_n_str(buf, 6, word, ' ', '\0'); | |
290 if (nwords > 5 && find_lib(ph, word[5]) == false) { | |
291 intptr_t base; | |
292 lib_info* lib; | |
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293 #ifdef _LP64 |
0 | 294 sscanf(word[0], "%lx", &base); |
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295 #else |
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296 sscanf(word[0], "%x", &base); |
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297 #endif |
0 | 298 if ((lib = add_lib_info(ph, word[5], (uintptr_t)base)) == NULL) |
299 continue; // ignore, add_lib_info prints error | |
300 | |
301 // we don't need to keep the library open, symtab is already | |
302 // built. Only for core dump we need to keep the fd open. | |
303 close(lib->fd); | |
304 lib->fd = -1; | |
305 } | |
306 } | |
307 fclose(fp); | |
308 return true; | |
309 } | |
310 | |
311 // detach a given pid | |
312 static bool ptrace_detach(pid_t pid) { | |
313 if (pid && ptrace(PTRACE_DETACH, pid, NULL, NULL) < 0) { | |
314 print_debug("ptrace(PTRACE_DETACH, ..) failed for %d\n", pid); | |
315 return false; | |
316 } else { | |
317 return true; | |
318 } | |
319 } | |
320 | |
321 // detach all pids of a ps_prochandle | |
322 static void detach_all_pids(struct ps_prochandle* ph) { | |
323 thread_info* thr = ph->threads; | |
324 while (thr) { | |
325 ptrace_detach(thr->lwp_id); | |
326 thr = thr->next; | |
327 } | |
328 } | |
329 | |
330 static void process_cleanup(struct ps_prochandle* ph) { | |
331 detach_all_pids(ph); | |
332 } | |
333 | |
334 static ps_prochandle_ops process_ops = { | |
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335 .release= process_cleanup, |
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336 .p_pread= process_read_data, |
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337 .p_pwrite= process_write_data, |
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338 .get_lwp_regs= process_get_lwp_regs |
0 | 339 }; |
340 | |
341 // attach to the process. One and only one exposed stuff | |
342 struct ps_prochandle* Pgrab(pid_t pid) { | |
343 struct ps_prochandle* ph = NULL; | |
344 thread_info* thr = NULL; | |
345 | |
346 if ( (ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle))) == NULL) { | |
347 print_debug("can't allocate memory for ps_prochandle\n"); | |
348 return NULL; | |
349 } | |
350 | |
351 if (ptrace_attach(pid) != true) { | |
352 free(ph); | |
353 return NULL; | |
354 } | |
355 | |
356 // initialize ps_prochandle | |
357 ph->pid = pid; | |
358 | |
359 // initialize vtable | |
360 ph->ops = &process_ops; | |
361 | |
362 // read library info and symbol tables, must do this before attaching threads, | |
363 // as the symbols in the pthread library will be used to figure out | |
364 // the list of threads within the same process. | |
365 read_lib_info(ph); | |
366 | |
367 // read thread info | |
368 read_thread_info(ph, add_new_thread); | |
369 | |
370 // attach to the threads | |
371 thr = ph->threads; | |
372 while (thr) { | |
373 // don't attach to the main thread again | |
374 if (ph->pid != thr->lwp_id && ptrace_attach(thr->lwp_id) != true) { | |
375 // even if one attach fails, we get return NULL | |
376 Prelease(ph); | |
377 return NULL; | |
378 } | |
379 thr = thr->next; | |
380 } | |
381 return ph; | |
382 } |