trace.c revision 7d5c8f257a74ac0d12828962a492e8b84ef83923
1/* 2 * Backtrace debugging 3 * Copyright (c) 2009, Jouni Malinen <j@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 16static 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 27static char *prg_fname = NULL; 28static bfd *cached_abfd = NULL; 29static asymbol **syms = NULL; 30 31static 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 46static 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 74static 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 117struct 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 126static 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 154static 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 aname = NULL; 191 192 data.found = bfd_find_inliner_info(abfd, &data.filename, 193 &data.function, &data.line); 194 } while (data.found); 195} 196 197 198static const char * wpa_trace_bfd_addr2func(void *pc) 199{ 200 bfd *abfd = cached_abfd; 201 struct bfd_data data; 202 203 if (abfd == NULL) 204 return NULL; 205 206 data.pc = (bfd_vma) pc; 207 data.found = FALSE; 208 bfd_map_over_sections(abfd, find_addr_sect, &data); 209 210 if (!data.found) 211 return NULL; 212 213 return data.function; 214} 215 216 217static void wpa_trace_bfd_init(void) 218{ 219 if (!prg_fname) { 220 get_prg_fname(); 221 if (!prg_fname) 222 return; 223 } 224 225 if (!cached_abfd) { 226 cached_abfd = open_bfd(prg_fname); 227 if (!cached_abfd) { 228 wpa_printf(MSG_INFO, "Failed to open bfd"); 229 return; 230 } 231 } 232 233 read_syms(cached_abfd); 234 if (!syms) { 235 wpa_printf(MSG_INFO, "Failed to read symbols"); 236 return; 237 } 238} 239 240 241void wpa_trace_dump_funcname(const char *title, void *pc) 242{ 243 wpa_printf(MSG_INFO, "WPA_TRACE: %s: %p", title, pc); 244 wpa_trace_bfd_init(); 245 wpa_trace_bfd_addr(pc); 246} 247 248#else /* WPA_TRACE_BFD */ 249 250#define wpa_trace_bfd_init() do { } while (0) 251#define wpa_trace_bfd_addr(pc) do { } while (0) 252#define wpa_trace_bfd_addr2func(pc) NULL 253 254#endif /* WPA_TRACE_BFD */ 255 256void wpa_trace_dump_func(const char *title, void **btrace, int btrace_num) 257{ 258 char **sym; 259 int i; 260 enum { TRACE_HEAD, TRACE_RELEVANT, TRACE_TAIL } state; 261 262 wpa_trace_bfd_init(); 263 wpa_printf(MSG_INFO, "WPA_TRACE: %s - START", title); 264 sym = backtrace_symbols(btrace, btrace_num); 265 state = TRACE_HEAD; 266 for (i = 0; i < btrace_num; i++) { 267 const char *func = wpa_trace_bfd_addr2func(btrace[i]); 268 if (state == TRACE_HEAD && func && 269 (os_strcmp(func, "wpa_trace_add_ref_func") == 0 || 270 os_strcmp(func, "wpa_trace_check_ref") == 0 || 271 os_strcmp(func, "wpa_trace_show") == 0)) 272 continue; 273 if (state == TRACE_TAIL && sym && sym[i] && 274 os_strstr(sym[i], "__libc_start_main")) 275 break; 276 if (state == TRACE_HEAD) 277 state = TRACE_RELEVANT; 278 if (sym) 279 wpa_printf(MSG_INFO, "[%d]: %s", i, sym[i]); 280 else 281 wpa_printf(MSG_INFO, "[%d]: ?? [%p]", i, btrace[i]); 282 wpa_trace_bfd_addr(btrace[i]); 283 if (state == TRACE_RELEVANT && func && 284 os_strcmp(func, "main") == 0) 285 state = TRACE_TAIL; 286 } 287 free(sym); 288 wpa_printf(MSG_INFO, "WPA_TRACE: %s - END", title); 289} 290 291 292void wpa_trace_show(const char *title) 293{ 294 struct info { 295 WPA_TRACE_INFO 296 } info; 297 wpa_trace_record(&info); 298 wpa_trace_dump(title, &info); 299} 300 301 302void wpa_trace_add_ref_func(struct wpa_trace_ref *ref, const void *addr) 303{ 304 if (addr == NULL) 305 return; 306 ref->addr = addr; 307 wpa_trace_record(ref); 308 dl_list_add(&active_references, &ref->list); 309} 310 311 312void wpa_trace_check_ref(const void *addr) 313{ 314 struct wpa_trace_ref *ref; 315 dl_list_for_each(ref, &active_references, struct wpa_trace_ref, list) { 316 if (addr != ref->addr) 317 continue; 318 wpa_trace_show("Freeing referenced memory"); 319 wpa_trace_dump("Reference registration", ref); 320 abort(); 321 } 322} 323 324#endif /* WPA_TRACE */ 325