1 /* 2 * Copyright 2003-2008 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 }