1 /* 2 * Backtrace debugging 3 * Copyright (c) 2009, Jouni Malinen <j (at) w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 11 #include "common.h" 12 #include "trace.h" 13 14 #ifdef WPA_TRACE 15 16 static struct dl_list active_references = 17 { &active_references, &active_references }; 18 19 #ifdef WPA_TRACE_BFD 20 #include <bfd.h> 21 #ifdef __linux__ 22 #include <demangle.h> 23 #else /* __linux__ */ 24 #include <libiberty/demangle.h> 25 #endif /* __linux__ */ 26 27 static char *prg_fname = NULL; 28 static bfd *cached_abfd = NULL; 29 static asymbol **syms = NULL; 30 31 static void get_prg_fname(void) 32 { 33 char exe[50], fname[512]; 34 int len; 35 os_snprintf(exe, sizeof(exe) - 1, "/proc/%u/exe", getpid()); 36 len = readlink(exe, fname, sizeof(fname) - 1); 37 if (len < 0 || len >= (int) sizeof(fname)) { 38 perror("readlink"); 39 return; 40 } 41 fname[len] = '\0'; 42 prg_fname = strdup(fname); 43 } 44 45 46 static bfd * open_bfd(const char *fname) 47 { 48 bfd *abfd; 49 char **matching; 50 51 abfd = bfd_openr(prg_fname, NULL); 52 if (abfd == NULL) { 53 wpa_printf(MSG_INFO, "bfd_openr failed"); 54 return NULL; 55 } 56 57 if (bfd_check_format(abfd, bfd_archive)) { 58 wpa_printf(MSG_INFO, "bfd_check_format failed"); 59 bfd_close(abfd); 60 return NULL; 61 } 62 63 if (!bfd_check_format_matches(abfd, bfd_object, &matching)) { 64 wpa_printf(MSG_INFO, "bfd_check_format_matches failed"); 65 free(matching); 66 bfd_close(abfd); 67 return NULL; 68 } 69 70 return abfd; 71 } 72 73 74 static void read_syms(bfd *abfd) 75 { 76 long storage, symcount; 77 bfd_boolean dynamic = FALSE; 78 79 if (syms) 80 return; 81 82 if (!(bfd_get_file_flags(abfd) & HAS_SYMS)) { 83 wpa_printf(MSG_INFO, "No symbols"); 84 return; 85 } 86 87 storage = bfd_get_symtab_upper_bound(abfd); 88 if (storage == 0) { 89 storage = bfd_get_dynamic_symtab_upper_bound(abfd); 90 dynamic = TRUE; 91 } 92 if (storage < 0) { 93 wpa_printf(MSG_INFO, "Unknown symtab upper bound"); 94 return; 95 } 96 97 syms = malloc(storage); 98 if (syms == NULL) { 99 wpa_printf(MSG_INFO, "Failed to allocate memory for symtab " 100 "(%ld bytes)", storage); 101 return; 102 } 103 if (dynamic) 104 symcount = bfd_canonicalize_dynamic_symtab(abfd, syms); 105 else 106 symcount = bfd_canonicalize_symtab(abfd, syms); 107 if (symcount < 0) { 108 wpa_printf(MSG_INFO, "Failed to canonicalize %ssymtab", 109 dynamic ? "dynamic " : ""); 110 free(syms); 111 syms = NULL; 112 return; 113 } 114 } 115 116 117 struct bfd_data { 118 bfd_vma pc; 119 bfd_boolean found; 120 const char *filename; 121 const char *function; 122 unsigned int line; 123 }; 124 125 126 static void find_addr_sect(bfd *abfd, asection *section, void *obj) 127 { 128 struct bfd_data *data = obj; 129 bfd_vma vma; 130 bfd_size_type size; 131 132 if (data->found) 133 return; 134 135 if (!(bfd_get_section_vma(abfd, section))) 136 return; 137 138 vma = bfd_get_section_vma(abfd, section); 139 if (data->pc < vma) 140 return; 141 142 size = bfd_get_section_size(section); 143 if (data->pc >= vma + size) 144 return; 145 146 data->found = bfd_find_nearest_line(abfd, section, syms, 147 data->pc - vma, 148 &data->filename, 149 &data->function, 150 &data->line); 151 } 152 153 154 static void wpa_trace_bfd_addr(void *pc) 155 { 156 bfd *abfd = cached_abfd; 157 struct bfd_data data; 158 const char *name; 159 char *aname = NULL; 160 const char *filename; 161 162 if (abfd == NULL) 163 return; 164 165 data.pc = (bfd_vma) pc; 166 data.found = FALSE; 167 bfd_map_over_sections(abfd, find_addr_sect, &data); 168 169 if (!data.found) 170 return; 171 172 do { 173 if (data.function) 174 aname = bfd_demangle(abfd, data.function, 175 DMGL_ANSI | DMGL_PARAMS); 176 name = aname ? aname : data.function; 177 filename = data.filename; 178 if (filename) { 179 char *end = os_strrchr(filename, '/'); 180 int i = 0; 181 while (*filename && *filename == prg_fname[i] && 182 filename <= end) { 183 filename++; 184 i++; 185 } 186 } 187 wpa_printf(MSG_INFO, " %s() %s:%u", 188 name, filename, data.line); 189 free(aname); 190 191 data.found = bfd_find_inliner_info(abfd, &data.filename, 192 &data.function, &data.line); 193 } while (data.found); 194 } 195 196 197 static const char * wpa_trace_bfd_addr2func(void *pc) 198 { 199 bfd *abfd = cached_abfd; 200 struct bfd_data data; 201 202 if (abfd == NULL) 203 return NULL; 204 205 data.pc = (bfd_vma) pc; 206 data.found = FALSE; 207 bfd_map_over_sections(abfd, find_addr_sect, &data); 208 209 if (!data.found) 210 return NULL; 211 212 return data.function; 213 } 214 215 216 static void wpa_trace_bfd_init(void) 217 { 218 if (!prg_fname) { 219 get_prg_fname(); 220 if (!prg_fname) 221 return; 222 } 223 224 if (!cached_abfd) { 225 cached_abfd = open_bfd(prg_fname); 226 if (!cached_abfd) { 227 wpa_printf(MSG_INFO, "Failed to open bfd"); 228 return; 229 } 230 } 231 232 read_syms(cached_abfd); 233 if (!syms) { 234 wpa_printf(MSG_INFO, "Failed to read symbols"); 235 return; 236 } 237 } 238 239 240 void wpa_trace_dump_funcname(const char *title, void *pc) 241 { 242 wpa_printf(MSG_INFO, "WPA_TRACE: %s: %p", title, pc); 243 wpa_trace_bfd_init(); 244 wpa_trace_bfd_addr(pc); 245 } 246 247 #else /* WPA_TRACE_BFD */ 248 249 #define wpa_trace_bfd_init() do { } while (0) 250 #define wpa_trace_bfd_addr(pc) do { } while (0) 251 #define wpa_trace_bfd_addr2func(pc) NULL 252 253 #endif /* WPA_TRACE_BFD */ 254 255 void wpa_trace_dump_func(const char *title, void **btrace, int btrace_num) 256 { 257 char **sym; 258 int i; 259 enum { TRACE_HEAD, TRACE_RELEVANT, TRACE_TAIL } state; 260 261 wpa_trace_bfd_init(); 262 wpa_printf(MSG_INFO, "WPA_TRACE: %s - START", title); 263 sym = backtrace_symbols(btrace, btrace_num); 264 state = TRACE_HEAD; 265 for (i = 0; i < btrace_num; i++) { 266 const char *func = wpa_trace_bfd_addr2func(btrace[i]); 267 if (state == TRACE_HEAD && func && 268 (os_strcmp(func, "wpa_trace_add_ref_func") == 0 || 269 os_strcmp(func, "wpa_trace_check_ref") == 0 || 270 os_strcmp(func, "wpa_trace_show") == 0)) 271 continue; 272 if (state == TRACE_TAIL && sym && sym[i] && 273 os_strstr(sym[i], "__libc_start_main")) 274 break; 275 if (state == TRACE_HEAD) 276 state = TRACE_RELEVANT; 277 if (sym) 278 wpa_printf(MSG_INFO, "[%d]: %s", i, sym[i]); 279 else 280 wpa_printf(MSG_INFO, "[%d]: ?? [%p]", i, btrace[i]); 281 wpa_trace_bfd_addr(btrace[i]); 282 if (state == TRACE_RELEVANT && func && 283 os_strcmp(func, "main") == 0) 284 state = TRACE_TAIL; 285 } 286 free(sym); 287 wpa_printf(MSG_INFO, "WPA_TRACE: %s - END", title); 288 } 289 290 291 void wpa_trace_show(const char *title) 292 { 293 struct info { 294 WPA_TRACE_INFO 295 } info; 296 wpa_trace_record(&info); 297 wpa_trace_dump(title, &info); 298 } 299 300 301 void wpa_trace_add_ref_func(struct wpa_trace_ref *ref, const void *addr) 302 { 303 if (addr == NULL) 304 return; 305 ref->addr = addr; 306 wpa_trace_record(ref); 307 dl_list_add(&active_references, &ref->list); 308 } 309 310 311 void wpa_trace_check_ref(const void *addr) 312 { 313 struct wpa_trace_ref *ref; 314 dl_list_for_each(ref, &active_references, struct wpa_trace_ref, list) { 315 if (addr != ref->addr) 316 continue; 317 wpa_trace_show("Freeing referenced memory"); 318 wpa_trace_dump("Reference registration", ref); 319 abort(); 320 } 321 } 322 323 #endif /* WPA_TRACE */ 324
