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comparison agent/src/os/linux/ps_proc.c @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2003-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <errno.h>
29 #include <sys/ptrace.h>
30 #include "libproc_impl.h"
31
32 #if defined(x86_64) && !defined(amd64)
33 #define amd64 1
34 #endif
35
36 #ifndef __WALL
37 #define __WALL 0x40000000 // Copied from /usr/include/linux/wait.h
38 #endif
39
40 // This file has the libproc implementation specific to live process
41 // For core files, refer to ps_core.c
42
43 static inline uintptr_t align(uintptr_t ptr, size_t size) {
44 return (ptr & ~(size - 1));
45 }
46
47 // ---------------------------------------------
48 // ptrace functions
49 // ---------------------------------------------
50
51 // read "size" bytes of data from "addr" within the target process.
52 // unlike the standard ptrace() function, process_read_data() can handle
53 // unaligned address - alignment check, if required, should be done
54 // before calling process_read_data.
55
56 static bool process_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
57 long rslt;
58 size_t i, words;
59 uintptr_t end_addr = addr + size;
60 uintptr_t aligned_addr = align(addr, sizeof(long));
61
62 if (aligned_addr != addr) {
63 char *ptr = (char *)&rslt;
64 errno = 0;
65 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0);
66 if (errno) {
67 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr);
68 return false;
69 }
70 for (; aligned_addr != addr; aligned_addr++, ptr++);
71 for (; ((intptr_t)aligned_addr % sizeof(long)) && aligned_addr < end_addr;
72 aligned_addr++)
73 *(buf++) = *(ptr++);
74 }
75
76 words = (end_addr - aligned_addr) / sizeof(long);
77
78 // assert((intptr_t)aligned_addr % sizeof(long) == 0);
79 for (i = 0; i < words; i++) {
80 errno = 0;
81 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0);
82 if (errno) {
83 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr);
84 return false;
85 }
86 *(long *)buf = rslt;
87 buf += sizeof(long);
88 aligned_addr += sizeof(long);
89 }
90
91 if (aligned_addr != end_addr) {
92 char *ptr = (char *)&rslt;
93 errno = 0;
94 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0);
95 if (errno) {
96 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr);
97 return false;
98 }
99 for (; aligned_addr != end_addr; aligned_addr++)
100 *(buf++) = *(ptr++);
101 }
102 return true;
103 }
104
105 // null implementation for write
106 static bool process_write_data(struct ps_prochandle* ph,
107 uintptr_t addr, const char *buf , size_t size) {
108 return false;
109 }
110
111 // "user" should be a pointer to a user_regs_struct
112 static bool process_get_lwp_regs(struct ps_prochandle* ph, pid_t pid, struct user_regs_struct *user) {
113 // we have already attached to all thread 'pid's, just use ptrace call
114 // to get regset now. Note that we don't cache regset upfront for processes.
115 // Linux on x86 and sparc are different. On x86 ptrace(PTRACE_GETREGS, ...)
116 // uses pointer from 4th argument and ignores 3rd argument. On sparc it uses
117 // pointer from 3rd argument and ignores 4th argument
118 #if defined(sparc) || defined(sparcv9)
119 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, addr, data)
120 #else
121 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, data, addr)
122 #endif
123
124 #ifdef _LP64
125 #ifdef PTRACE_GETREGS64
126 #define PTRACE_GETREGS_REQ PTRACE_GETREGS64
127 #endif
128 #else
129 #if defined(PTRACE_GETREGS) || defined(PT_GETREGS)
130 #define PTRACE_GETREGS_REQ PTRACE_GETREGS
131 #endif
132 #endif /* _LP64 */
133
134 #ifdef PTRACE_GETREGS_REQ
135 if (ptrace_getregs(PTRACE_GETREGS_REQ, pid, user, NULL) < 0) {
136 print_debug("ptrace(PTRACE_GETREGS, ...) failed for lwp %d\n", pid);
137 return false;
138 }
139 return true;
140 #else
141 print_debug("ptrace(PTRACE_GETREGS, ...) not supported\n");
142 return false;
143 #endif
144
145 }
146
147 // attach to a process/thread specified by "pid"
148 static bool ptrace_attach(pid_t pid) {
149 if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) {
150 print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid);
151 return false;
152 } else {
153 int ret;
154 int status;
155 do {
156 // Wait for debuggee to stop.
157 ret = waitpid(pid, &status, 0);
158 if (ret == -1 && errno == ECHILD) {
159 // try cloned process.
160 ret = waitpid(pid, &status, __WALL);
161 }
162 if (ret >= 0) {
163 if (WIFSTOPPED(status)) {
164 // Debuggee stopped.
165 return true;
166 } else {
167 print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status);
168 return false;
169 }
170 } else {
171 switch (errno) {
172 case EINTR:
173 continue;
174 break;
175 case ECHILD:
176 print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid);
177 break;
178 case EINVAL:
179 print_debug("waitpid() failed. Invalid options argument.\n");
180 break;
181 default:
182 print_debug("waitpid() failed. Unexpected error %d\n",errno);
183 }
184 return false;
185 }
186 } while(true);
187 }
188 }
189
190 // -------------------------------------------------------
191 // functions for obtaining library information
192 // -------------------------------------------------------
193
194 /*
195 * splits a string _str_ into substrings with delimiter _delim_ by replacing old * delimiters with _new_delim_ (ideally, '\0'). the address of each substring
196 * is stored in array _ptrs_ as the return value. the maximum capacity of _ptrs_ * array is specified by parameter _n_.
197 * RETURN VALUE: total number of substrings (always <= _n_)
198 * NOTE: string _str_ is modified if _delim_!=_new_delim_
199 */
200 static int split_n_str(char * str, int n, char ** ptrs, char delim, char new_delim)
201 {
202 int i;
203 for(i = 0; i < n; i++) ptrs[i] = NULL;
204 if (str == NULL || n < 1 ) return 0;
205
206 i = 0;
207
208 // skipping leading blanks
209 while(*str&&*str==delim) str++;
210
211 while(*str&&i<n){
212 ptrs[i++] = str;
213 while(*str&&*str!=delim) str++;
214 while(*str&&*str==delim) *(str++) = new_delim;
215 }
216
217 return i;
218 }
219
220 /*
221 * fgets without storing '\n' at the end of the string
222 */
223 static char * fgets_no_cr(char * buf, int n, FILE *fp)
224 {
225 char * rslt = fgets(buf, n, fp);
226 if (rslt && buf && *buf){
227 char *p = strchr(buf, '\0');
228 if (*--p=='\n') *p='\0';
229 }
230 return rslt;
231 }
232
233 // callback for read_thread_info
234 static bool add_new_thread(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {
235 return add_thread_info(ph, pthread_id, lwp_id) != NULL;
236 }
237
238 static bool read_lib_info(struct ps_prochandle* ph) {
239 char fname[32];
240 char buf[256];
241 FILE *fp = NULL;
242
243 sprintf(fname, "/proc/%d/maps", ph->pid);
244 fp = fopen(fname, "r");
245 if (fp == NULL) {
246 print_debug("can't open /proc/%d/maps file\n", ph->pid);
247 return false;
248 }
249
250 while(fgets_no_cr(buf, 256, fp)){
251 char * word[6];
252 int nwords = split_n_str(buf, 6, word, ' ', '\0');
253 if (nwords > 5 && find_lib(ph, word[5]) == false) {
254 intptr_t base;
255 lib_info* lib;
256 sscanf(word[0], "%lx", &base);
257 if ((lib = add_lib_info(ph, word[5], (uintptr_t)base)) == NULL)
258 continue; // ignore, add_lib_info prints error
259
260 // we don't need to keep the library open, symtab is already
261 // built. Only for core dump we need to keep the fd open.
262 close(lib->fd);
263 lib->fd = -1;
264 }
265 }
266 fclose(fp);
267 return true;
268 }
269
270 // detach a given pid
271 static bool ptrace_detach(pid_t pid) {
272 if (pid && ptrace(PTRACE_DETACH, pid, NULL, NULL) < 0) {
273 print_debug("ptrace(PTRACE_DETACH, ..) failed for %d\n", pid);
274 return false;
275 } else {
276 return true;
277 }
278 }
279
280 // detach all pids of a ps_prochandle
281 static void detach_all_pids(struct ps_prochandle* ph) {
282 thread_info* thr = ph->threads;
283 while (thr) {
284 ptrace_detach(thr->lwp_id);
285 thr = thr->next;
286 }
287 }
288
289 static void process_cleanup(struct ps_prochandle* ph) {
290 detach_all_pids(ph);
291 }
292
293 static ps_prochandle_ops process_ops = {
294 release: process_cleanup,
295 p_pread: process_read_data,
296 p_pwrite: process_write_data,
297 get_lwp_regs: process_get_lwp_regs
298 };
299
300 // attach to the process. One and only one exposed stuff
301 struct ps_prochandle* Pgrab(pid_t pid) {
302 struct ps_prochandle* ph = NULL;
303 thread_info* thr = NULL;
304
305 if ( (ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle))) == NULL) {
306 print_debug("can't allocate memory for ps_prochandle\n");
307 return NULL;
308 }
309
310 if (ptrace_attach(pid) != true) {
311 free(ph);
312 return NULL;
313 }
314
315 // initialize ps_prochandle
316 ph->pid = pid;
317
318 // initialize vtable
319 ph->ops = &process_ops;
320
321 // read library info and symbol tables, must do this before attaching threads,
322 // as the symbols in the pthread library will be used to figure out
323 // the list of threads within the same process.
324 read_lib_info(ph);
325
326 // read thread info
327 read_thread_info(ph, add_new_thread);
328
329 // attach to the threads
330 thr = ph->threads;
331 while (thr) {
332 // don't attach to the main thread again
333 if (ph->pid != thr->lwp_id && ptrace_attach(thr->lwp_id) != true) {
334 // even if one attach fails, we get return NULL
335 Prelease(ph);
336 return NULL;
337 }
338 thr = thr->next;
339 }
340 return ph;
341 }