src/utils/trace.c

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