1 #ifdef USE_PRAGMA_IDENT_SRC 2 #pragma ident "@(#)ps_proc.c 1.17 07/05/05 17:02:02 JVM" 3 #endif 4 /* 5 * Copyright 2003-2007 Sun Microsystems, Inc. All Rights Reserved. 6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 7 * 8 * This code is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License version 2 only, as 10 * published by the Free Software Foundation. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 23 * CA 95054 USA or visit www.sun.com if you need additional information or 24 * have any questions. 25 * 26 */ 27 28 #include <stdio.h> 29 #include <stdlib.h> 30 #include <string.h> 31 #include <errno.h> 32 #include <sys/ptrace.h> 33 #include "libproc_impl.h" 34 35 #if defined(x86_64) && !defined(amd64) 36 #define amd64 1 37 #endif 38 39 #ifndef __WALL 40 #define __WALL 0x40000000 // Copied from /usr/include/linux/wait.h 41 #endif 42 43 // This file has the libproc implementation specific to live process 44 // For core files, refer to ps_core.c 45 46 static inline uintptr_t align(uintptr_t ptr, size_t size) { 47 return (ptr & ~(size - 1)); 48 } 49 50 // --------------------------------------------- 51 // ptrace functions 52 // --------------------------------------------- 53 54 // read "size" bytes of data from "addr" within the target process. 55 // unlike the standard ptrace() function, process_read_data() can handle 56 // unaligned address - alignment check, if required, should be done 57 // before calling process_read_data. 58 59 static bool process_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) { 60 long rslt; 61 size_t i, words; 62 uintptr_t end_addr = addr + size; 63 uintptr_t aligned_addr = align(addr, sizeof(long)); 64 65 if (aligned_addr != addr) { 66 char *ptr = (char *)&rslt; 67 errno = 0; 68 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); 69 if (errno) { 70 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); 71 return false; 72 } 73 for (; aligned_addr != addr; aligned_addr++, ptr++); 74 for (; ((intptr_t)aligned_addr % sizeof(long)) && aligned_addr < end_addr; 75 aligned_addr++) 76 *(buf++) = *(ptr++); 77 } 78 79 words = (end_addr - aligned_addr) / sizeof(long); 80 81 // assert((intptr_t)aligned_addr % sizeof(long) == 0); 82 for (i = 0; i < words; i++) { 83 errno = 0; 84 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); 85 if (errno) { 86 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); 87 return false; 88 } 89 *(long *)buf = rslt; 90 buf += sizeof(long); 91 aligned_addr += sizeof(long); 92 } 93 94 if (aligned_addr != end_addr) { 95 char *ptr = (char *)&rslt; 96 errno = 0; 97 rslt = ptrace(PTRACE_PEEKDATA, ph->pid, aligned_addr, 0); 98 if (errno) { 99 print_debug("ptrace(PTRACE_PEEKDATA, ..) failed for %d bytes @ %lx\n", size, addr); 100 return false; 101 } 102 for (; aligned_addr != end_addr; aligned_addr++) 103 *(buf++) = *(ptr++); 104 } 105 return true; 106 } 107 108 // null implementation for write 109 static bool process_write_data(struct ps_prochandle* ph, 110 uintptr_t addr, const char *buf , size_t size) { 111 return false; 112 } 113 114 // "user" should be a pointer to a user_regs_struct 115 static bool process_get_lwp_regs(struct ps_prochandle* ph, pid_t pid, struct user_regs_struct *user) { 116 // we have already attached to all thread 'pid's, just use ptrace call 117 // to get regset now. Note that we don't cache regset upfront for processes. 118 // Linux on x86 and sparc are different. On x86 ptrace(PTRACE_GETREGS, ...) 119 // uses pointer from 4th argument and ignores 3rd argument. On sparc it uses 120 // pointer from 3rd argument and ignores 4th argument 121 #if defined(sparc) || defined(sparcv9) 122 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, addr, data) 123 #else 124 #define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, data, addr) 125 #endif 126 127 #ifdef _LP64 128 #ifdef PTRACE_GETREGS64 129 #define PTRACE_GETREGS_REQ PTRACE_GETREGS64 130 #endif 131 #else 132 #if defined(PTRACE_GETREGS) || defined(PT_GETREGS) 133 #define PTRACE_GETREGS_REQ PTRACE_GETREGS 134 #endif 135 #endif /* _LP64 */ 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; 143 #else 144 print_debug("ptrace(PTRACE_GETREGS, ...) not supported\n"); 145 return false; 146 #endif 147 148 } 149 150 // attach to a process/thread specified by "pid" 151 static bool ptrace_attach(pid_t pid) { 152 if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) { 153 print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid); 154 return false; 155 } else { 156 int ret; 157 int status; 158 do { 159 // Wait for debuggee to stop. 160 ret = waitpid(pid, &status, 0); 161 if (ret == -1 && errno == ECHILD) { 162 // try cloned process. 163 ret = waitpid(pid, &status, __WALL); 164 } 165 if (ret >= 0) { 166 if (WIFSTOPPED(status)) { 167 // Debuggee stopped. 168 return true; 169 } else { 170 print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status); 171 return false; 172 } 173 } else { 174 switch (errno) { 175 case EINTR: 176 continue; 177 break; 178 case ECHILD: 179 print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid); 180 break; 181 case EINVAL: 182 print_debug("waitpid() failed. Invalid options argument.\n"); 183 break; 184 default: 185 print_debug("waitpid() failed. Unexpected error %d\n",errno); 186 } 187 return false; 188 } 189 } while(true); 190 } 191 } 192 193 // ------------------------------------------------------- 194 // functions for obtaining library information 195 // ------------------------------------------------------- 196 197 /* 198 * splits a string _str_ into substrings with delimiter _delim_ by replacing old * delimiters with _new_delim_ (ideally, '\0'). the address of each substring 199 * is stored in array _ptrs_ as the return value. the maximum capacity of _ptrs_ * array is specified by parameter _n_. 200 * RETURN VALUE: total number of substrings (always <= _n_) 201 * NOTE: string _str_ is modified if _delim_!=_new_delim_ 202 */ 203 static int split_n_str(char * str, int n, char ** ptrs, char delim, char new_delim) 204 { 205 int i; 206 for(i = 0; i < n; i++) ptrs[i] = NULL; 207 if (str == NULL || n < 1 ) return 0; 208 209 i = 0; 210 211 // skipping leading blanks 212 while(*str&&*str==delim) str++; 213 214 while(*str&&i<n){ 215 ptrs[i++] = str; 216 while(*str&&*str!=delim) str++; 217 while(*str&&*str==delim) *(str++) = new_delim; 218 } 219 220 return i; 221 } 222 223 /* 224 * fgets without storing '\n' at the end of the string 225 */ 226 static char * fgets_no_cr(char * buf, int n, FILE *fp) 227 { 228 char * rslt = fgets(buf, n, fp); 229 if (rslt && buf && *buf){ 230 char *p = strchr(buf, '\0'); 231 if (*--p=='\n') *p='\0'; 232 } 233 return rslt; 234 } 235 236 // callback for read_thread_info 237 static bool add_new_thread(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) { 238 return add_thread_info(ph, pthread_id, lwp_id) != NULL; 239 } 240 241 static bool read_lib_info(struct ps_prochandle* ph) { 242 char fname[32]; 243 char buf[256]; 244 FILE *fp = NULL; 245 246 sprintf(fname, "/proc/%d/maps", ph->pid); 247 fp = fopen(fname, "r"); 248 if (fp == NULL) { 249 print_debug("can't open /proc/%d/maps file\n", ph->pid); 250 return false; 251 } 252 253 while(fgets_no_cr(buf, 256, fp)){ 254 char * word[6]; 255 int nwords = split_n_str(buf, 6, word, ' ', '\0'); 256 if (nwords > 5 && find_lib(ph, word[5]) == false) { 257 intptr_t base; 258 lib_info* lib; 259 sscanf(word[0], "%lx", &base); 260 if ((lib = add_lib_info(ph, word[5], (uintptr_t)base)) == NULL) 261 continue; // ignore, add_lib_info prints error 262 263 // we don't need to keep the library open, symtab is already 264 // built. Only for core dump we need to keep the fd open. 265 close(lib->fd); 266 lib->fd = -1; 267 } 268 } 269 fclose(fp); 270 return true; 271 } 272 273 // detach a given pid 274 static bool ptrace_detach(pid_t pid) { 275 if (pid && ptrace(PTRACE_DETACH, pid, NULL, NULL) < 0) { 276 print_debug("ptrace(PTRACE_DETACH, ..) failed for %d\n", pid); 277 return false; 278 } else { 279 return true; 280 } 281 } 282 283 // detach all pids of a ps_prochandle 284 static void detach_all_pids(struct ps_prochandle* ph) { 285 thread_info* thr = ph->threads; 286 while (thr) { 287 ptrace_detach(thr->lwp_id); 288 thr = thr->next; 289 } 290 } 291 292 static void process_cleanup(struct ps_prochandle* ph) { 293 detach_all_pids(ph); 294 } 295 296 static ps_prochandle_ops process_ops = { 297 release: process_cleanup, 298 p_pread: process_read_data, 299 p_pwrite: process_write_data, 300 get_lwp_regs: process_get_lwp_regs 301 }; 302 303 // attach to the process. One and only one exposed stuff 304 struct ps_prochandle* Pgrab(pid_t pid) { 305 struct ps_prochandle* ph = NULL; 306 thread_info* thr = NULL; 307 308 if ( (ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle))) == NULL) { 309 print_debug("can't allocate memory for ps_prochandle\n"); 310 return NULL; 311 } 312 313 if (ptrace_attach(pid) != true) { 314 free(ph); 315 return NULL; 316 } 317 318 // initialize ps_prochandle 319 ph->pid = pid; 320 321 // initialize vtable 322 ph->ops = &process_ops; 323 324 // read library info and symbol tables, must do this before attaching threads, 325 // as the symbols in the pthread library will be used to figure out 326 // the list of threads within the same process. 327 read_lib_info(ph); 328 329 // read thread info 330 read_thread_info(ph, add_new_thread); 331 332 // attach to the threads 333 thr = ph->threads; 334 while (thr) { 335 // don't attach to the main thread again 336 if (ph->pid != thr->lwp_id && ptrace_attach(thr->lwp_id) != true) { 337 // even if one attach fails, we get return NULL 338 Prelease(ph); 339 return NULL; 340 } 341 thr = thr->next; 342 } 343 return ph; 344 }