Mercurial > hg > truffle
annotate agent/src/os/linux/ps_proc.c @ 8058:2394a89e89f4
8008088: SA can hang the VM
Reviewed-by: mgronlun, sla, dholmes
| author | rbackman |
|---|---|
| date | Wed, 13 Feb 2013 09:46:19 +0100 |
| parents | 0a8e0d4345b3 |
| children | f2512d89ad0c |
| rev | line source |
|---|---|
| 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> |
| 30 #include <sys/ptrace.h> | |
| 31 #include "libproc_impl.h" | |
| 32 | |
| 33 #if defined(x86_64) && !defined(amd64) | |
| 34 #define amd64 1 | |
| 35 #endif | |
| 36 | |
| 37 #ifndef __WALL | |
| 38 #define __WALL 0x40000000 // Copied from /usr/include/linux/wait.h | |
| 39 #endif | |
| 40 | |
| 41 // This file has the libproc implementation specific to live process | |
| 42 // For core files, refer to ps_core.c | |
| 43 | |
| 44 static inline uintptr_t align(uintptr_t ptr, size_t size) { | |
| 45 return (ptr & ~(size - 1)); | |
| 46 } | |
| 47 | |
| 48 // --------------------------------------------- | |
| 49 // ptrace functions | |
| 50 // --------------------------------------------- | |
| 51 | |
| 52 // read "size" bytes of data from "addr" within the target process. | |
| 53 // unlike the standard ptrace() function, process_read_data() can handle | |
| 54 // unaligned address - alignment check, if required, should be done | |
| 55 // before calling process_read_data. | |
| 56 | |
| 57 static bool process_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) { | |
| 58 long rslt; | |
| 59 size_t i, words; | |
| 60 uintptr_t end_addr = addr + size; | |
| 61 uintptr_t aligned_addr = align(addr, sizeof(long)); | |
| 62 | |
| 63 if (aligned_addr != addr) { | |
| 64 char *ptr = (char *)&rslt; | |
| 65 errno = 0; | |
| 66 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
| 67 if (errno) { | |
| 68 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
| 69 return false; | |
| 70 } | |
| 71 for (; aligned_addr != addr; aligned_addr++, ptr++); | |
| 72 for (; ((intptr_t)aligned_addr % sizeof(long)) && aligned_addr < end_addr; | |
| 73 aligned_addr++) | |
| 74 *(buf++) = *(ptr++); | |
| 75 } | |
| 76 | |
| 77 words = (end_addr - aligned_addr) / sizeof(long); | |
| 78 | |
| 79 // assert((intptr_t)aligned_addr % sizeof(long) == 0); | |
| 80 for (i = 0; i < words; i++) { | |
| 81 errno = 0; | |
| 82 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
| 83 if (errno) { | |
| 84 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
| 85 return false; | |
| 86 } | |
| 87 *(long *)buf = rslt; | |
| 88 buf += sizeof(long); | |
| 89 aligned_addr += sizeof(long); | |
| 90 } | |
| 91 | |
| 92 if (aligned_addr != end_addr) { | |
| 93 char *ptr = (char *)&rslt; | |
| 94 errno = 0; | |
| 95 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); | |
| 96 if (errno) { | |
| 97 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); | |
| 98 return false; | |
| 99 } | |
| 100 for (; aligned_addr != end_addr; aligned_addr++) | |
| 101 *(buf++) = *(ptr++); | |
| 102 } | |
| 103 return true; | |
| 104 } | |
| 105 | |
| 106 // null implementation for write | |
| 107 static bool process_write_data(struct ps_prochandle* ph, | |
| 108 uintptr_t addr, const char *buf , size_t size) { | |
| 109 return false; | |
| 110 } | |
| 111 | |
| 112 // "user" should be a pointer to a user_regs_struct | |
| 113 static bool process_get_lwp_regs(struct ps_prochandle* ph, pid_t pid, struct user_regs_struct *user) { | |
| 114 // we have already attached to all thread 'pid's, just use ptrace call | |
| 115 // to get regset now. Note that we don't cache regset upfront for processes. | |
| 116 // Linux on x86 and sparc are different. On x86 ptrace(PTRACE_GETREGS, ...) | |
| 117 // uses pointer from 4th argument and ignores 3rd argument. On sparc it uses | |
| 118 // pointer from 3rd argument and ignores 4th argument | |
| 119 #if defined(sparc) || defined(sparcv9) | |
| 120 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, addr, data) | |
| 121 #else | |
| 122 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, data, addr) | |
| 123 #endif | |
| 124 | |
| 1990 | 125 #if defined(_LP64) && defined(PTRACE_GETREGS64) |
| 0 | 126 #define PTRACE_GETREGS_REQ PTRACE_GETREGS64 |
| 1990 | 127 #elif defined(PTRACE_GETREGS) |
| 128 #define PTRACE_GETREGS_REQ PTRACE_GETREGS | |
| 129 #elif defined(PT_GETREGS) | |
| 130 #define PTRACE_GETREGS_REQ PT_GETREGS | |
| 0 | 131 #endif |
| 132 | |
| 133 #ifdef PTRACE_GETREGS_REQ | |
| 134 if (ptrace_getregs(PTRACE_GETREGS_REQ, pid, user, NULL) < 0) { | |
| 135 print_debug("ptrace(PTRACE_GETREGS, ...) failed for lwp %d\n", pid); | |
| 136 return false; | |
| 137 } | |
| 138 return true; | |
| 139 #else | |
| 140 print_debug("ptrace(PTRACE_GETREGS, ...) not supported\n"); | |
| 141 return false; | |
| 142 #endif | |
| 143 | |
| 144 } | |
| 145 | |
| 8058 | 146 static bool ptrace_continue(pid_t pid, int signal) { |
| 147 // pass the signal to the process so we don't swallow it | |
| 148 if (ptrace(PTRACE_CONT, pid, NULL, signal) < 0) { | |
| 149 print_debug("ptrace(PTRACE_CONT, ..) failed for %d\n", pid); | |
| 150 return false; | |
| 151 } | |
| 152 return true; | |
| 153 } | |
| 154 | |
| 155 // waits until the ATTACH has stopped the process | |
| 156 // by signal SIGSTOP | |
| 157 static bool ptrace_waitpid(pid_t pid) { | |
| 158 int ret; | |
| 159 int status; | |
| 160 while (true) { | |
| 161 // Wait for debuggee to stop. | |
| 162 ret = waitpid(pid, &status, 0); | |
| 163 if (ret == -1 && errno == ECHILD) { | |
| 164 // try cloned process. | |
| 165 ret = waitpid(pid, &status, __WALL); | |
| 166 } | |
| 167 if (ret >= 0) { | |
| 168 if (WIFSTOPPED(status)) { | |
| 169 // Any signal will stop the thread, make sure it is SIGSTOP. Otherwise SIGSTOP | |
| 170 // will still be pending and delivered when the process is DETACHED and the process | |
| 171 // will go to sleep. | |
| 172 if (WSTOPSIG(status) == SIGSTOP) { | |
| 173 // Debuggee stopped by SIGSTOP. | |
| 174 return true; | |
| 175 } | |
| 176 if (!ptrace_continue(pid, WSTOPSIG(status))) { | |
| 177 print_error("Failed to correctly attach to VM. VM might HANG! [PTRACE_CONT failed, stopped by %d]\n", WSTOPSIG(status)); | |
| 178 return false; | |
| 179 } | |
| 180 } else { | |
| 181 print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status); | |
| 182 return false; | |
| 183 } | |
| 184 } else { | |
| 185 switch (errno) { | |
| 186 case EINTR: | |
| 187 continue; | |
| 188 break; | |
| 189 case ECHILD: | |
| 190 print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid); | |
| 191 break; | |
| 192 case EINVAL: | |
| 193 print_debug("waitpid() failed. Invalid options argument.\n"); | |
| 194 break; | |
| 195 default: | |
| 196 print_debug("waitpid() failed. Unexpected error %d\n",errno); | |
| 197 break; | |
| 198 } | |
| 199 return false; | |
| 200 } | |
| 201 } | |
| 202 } | |
| 203 | |
| 0 | 204 // attach to a process/thread specified by "pid" |
| 205 static bool ptrace_attach(pid_t pid) { | |
| 206 if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) { | |
| 207 print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid); | |
| 208 return false; | |
| 209 } else { | |
| 8058 | 210 return ptrace_waitpid(pid); |
| 0 | 211 } |
| 212 } | |
| 213 | |
| 214 // ------------------------------------------------------- | |
| 215 // functions for obtaining library information | |
| 216 // ------------------------------------------------------- | |
| 217 | |
| 218 /* | |
| 219 * splits a string _str_ into substrings with delimiter _delim_ by replacing old * delimiters with _new_delim_ (ideally, '\0'). the address of each substring | |
| 220 * is stored in array _ptrs_ as the return value. the maximum capacity of _ptrs_ * array is specified by parameter _n_. | |
| 221 * RETURN VALUE: total number of substrings (always <= _n_) | |
| 222 * NOTE: string _str_ is modified if _delim_!=_new_delim_ | |
| 223 */ | |
| 224 static int split_n_str(char * str, int n, char ** ptrs, char delim, char new_delim) | |
| 225 { | |
| 226 int i; | |
| 227 for(i = 0; i < n; i++) ptrs[i] = NULL; | |
| 228 if (str == NULL || n < 1 ) return 0; | |
| 229 | |
| 230 i = 0; | |
| 231 | |
| 232 // skipping leading blanks | |
| 233 while(*str&&*str==delim) str++; | |
| 234 | |
| 235 while(*str&&i<n){ | |
| 236 ptrs[i++] = str; | |
| 237 while(*str&&*str!=delim) str++; | |
| 238 while(*str&&*str==delim) *(str++) = new_delim; | |
| 239 } | |
| 240 | |
| 241 return i; | |
| 242 } | |
| 243 | |
| 244 /* | |
| 245 * fgets without storing '\n' at the end of the string | |
| 246 */ | |
| 247 static char * fgets_no_cr(char * buf, int n, FILE *fp) | |
| 248 { | |
| 249 char * rslt = fgets(buf, n, fp); | |
| 250 if (rslt && buf && *buf){ | |
| 251 char *p = strchr(buf, '\0'); | |
| 252 if (*--p=='\n') *p='\0'; | |
| 253 } | |
| 254 return rslt; | |
| 255 } | |
| 256 | |
| 257 // callback for read_thread_info | |
| 258 static bool add_new_thread(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) { | |
| 259 return add_thread_info(ph, pthread_id, lwp_id) != NULL; | |
| 260 } | |
| 261 | |
| 262 static bool read_lib_info(struct ps_prochandle* ph) { | |
| 263 char fname[32]; | |
| 264 char buf[256]; | |
| 265 FILE *fp = NULL; | |
| 266 | |
| 267 sprintf(fname, "/proc/%d/maps", ph->pid); | |
| 268 fp = fopen(fname, "r"); | |
| 269 if (fp == NULL) { | |
| 270 print_debug("can't open /proc/%d/maps file\n", ph->pid); | |
| 271 return false; | |
| 272 } | |
| 273 | |
| 274 while(fgets_no_cr(buf, 256, fp)){ | |
| 275 char * word[6]; | |
| 276 int nwords = split_n_str(buf, 6, word, ' ', '\0'); | |
| 277 if (nwords > 5 && find_lib(ph, word[5]) == false) { | |
| 278 intptr_t base; | |
| 279 lib_info* lib; | |
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280 #ifdef _LP64 |
| 0 | 281 sscanf(word[0], "%lx", &base); |
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282 #else |
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283 sscanf(word[0], "%x", &base); |
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284 #endif |
| 0 | 285 if ((lib = add_lib_info(ph, word[5], (uintptr_t)base)) == NULL) |
| 286 continue; // ignore, add_lib_info prints error | |
| 287 | |
| 288 // we don't need to keep the library open, symtab is already | |
| 289 // built. Only for core dump we need to keep the fd open. | |
| 290 close(lib->fd); | |
| 291 lib->fd = -1; | |
| 292 } | |
| 293 } | |
| 294 fclose(fp); | |
| 295 return true; | |
| 296 } | |
| 297 | |
| 298 // detach a given pid | |
| 299 static bool ptrace_detach(pid_t pid) { | |
| 300 if (pid && ptrace(PTRACE_DETACH, pid, NULL, NULL) < 0) { | |
| 301 print_debug("ptrace(PTRACE_DETACH, ..) failed for %d\n", pid); | |
| 302 return false; | |
| 303 } else { | |
| 304 return true; | |
| 305 } | |
| 306 } | |
| 307 | |
| 308 // detach all pids of a ps_prochandle | |
| 309 static void detach_all_pids(struct ps_prochandle* ph) { | |
| 310 thread_info* thr = ph->threads; | |
| 311 while (thr) { | |
| 312 ptrace_detach(thr->lwp_id); | |
| 313 thr = thr->next; | |
| 314 } | |
| 315 } | |
| 316 | |
| 317 static void process_cleanup(struct ps_prochandle* ph) { | |
| 318 detach_all_pids(ph); | |
| 319 } | |
| 320 | |
| 321 static ps_prochandle_ops process_ops = { | |
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322 .release= process_cleanup, |
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323 .p_pread= process_read_data, |
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324 .p_pwrite= process_write_data, |
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325 .get_lwp_regs= process_get_lwp_regs |
| 0 | 326 }; |
| 327 | |
| 328 // attach to the process. One and only one exposed stuff | |
| 329 struct ps_prochandle* Pgrab(pid_t pid) { | |
| 330 struct ps_prochandle* ph = NULL; | |
| 331 thread_info* thr = NULL; | |
| 332 | |
| 333 if ( (ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle))) == NULL) { | |
| 334 print_debug("can't allocate memory for ps_prochandle\n"); | |
| 335 return NULL; | |
| 336 } | |
| 337 | |
| 338 if (ptrace_attach(pid) != true) { | |
| 339 free(ph); | |
| 340 return NULL; | |
| 341 } | |
| 342 | |
| 343 // initialize ps_prochandle | |
| 344 ph->pid = pid; | |
| 345 | |
| 346 // initialize vtable | |
| 347 ph->ops = &process_ops; | |
| 348 | |
| 349 // read library info and symbol tables, must do this before attaching threads, | |
| 350 // as the symbols in the pthread library will be used to figure out | |
| 351 // the list of threads within the same process. | |
| 352 read_lib_info(ph); | |
| 353 | |
| 354 // read thread info | |
| 355 read_thread_info(ph, add_new_thread); | |
| 356 | |
| 357 // attach to the threads | |
| 358 thr = ph->threads; | |
| 359 while (thr) { | |
| 360 // don't attach to the main thread again | |
| 361 if (ph->pid != thr->lwp_id && ptrace_attach(thr->lwp_id) != true) { | |
| 362 // even if one attach fails, we get return NULL | |
| 363 Prelease(ph); | |
| 364 return NULL; | |
| 365 } | |
| 366 thr = thr->next; | |
| 367 } | |
| 368 return ph; | |
| 369 } |