kernel/tools/perf/util/srcline.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5 #include <linux/kernel.h>
   6
   7 #include "util/dso.h"
   8 #include "util/util.h"
   9 #include "util/debug.h"
  10
  11 #include "symbol.h"
  12
  13 #ifdef HAVE_LIBBFD_SUPPORT
  14
  15 /*
  16  * Implement addr2line using libbfd.
  17  */
  18 #define PACKAGE "perf"
  19 #include <bfd.h>
  20
  21 struct a2l_data {
  22         const char      *input;
  23         u64             addr;
  24
  25         bool            found;
  26         const char      *filename;
  27         const char      *funcname;
  28         unsigned        line;
  29
  30         bfd             *abfd;
  31         asymbol         **syms;
  32 };
  33
  34 static int bfd_error(const char *string)
  35 {
  36         const char *errmsg;
  37
  38         errmsg = bfd_errmsg(bfd_get_error());
  39         fflush(stdout);
  40
  41         if (string)
  42                 pr_debug("%s: %s\n", string, errmsg);
  43         else
  44                 pr_debug("%s\n", errmsg);
  45
  46         return -1;
  47 }
  48
  49 static int slurp_symtab(bfd *abfd, struct a2l_data *a2l)
  50 {
  51         long storage;
  52         long symcount;
  53         asymbol **syms;
  54         bfd_boolean dynamic = FALSE;
  55
  56         if ((bfd_get_file_flags(abfd) & HAS_SYMS) == 0)
  57                 return bfd_error(bfd_get_filename(abfd));
  58
  59         storage = bfd_get_symtab_upper_bound(abfd);
  60         if (storage == 0L) {
  61                 storage = bfd_get_dynamic_symtab_upper_bound(abfd);
  62                 dynamic = TRUE;
  63         }
  64         if (storage < 0L)
  65                 return bfd_error(bfd_get_filename(abfd));
  66
  67         syms = malloc(storage);
  68         if (dynamic)
  69                 symcount = bfd_canonicalize_dynamic_symtab(abfd, syms);
  70         else
  71                 symcount = bfd_canonicalize_symtab(abfd, syms);
  72
  73         if (symcount < 0) {
  74                 free(syms);
  75                 return bfd_error(bfd_get_filename(abfd));
  76         }
  77
  78         a2l->syms = syms;
  79         return 0;
  80 }
  81
  82 static void find_address_in_section(bfd *abfd, asection *section, void *data)
  83 {
  84         bfd_vma pc, vma;
  85         bfd_size_type size;
  86         struct a2l_data *a2l = data;
  87
  88         if (a2l->found)
  89                 return;
  90
  91         if ((bfd_get_section_flags(abfd, section) & SEC_ALLOC) == 0)
  92                 return;
  93
  94         pc = a2l->addr;
  95         vma = bfd_get_section_vma(abfd, section);
  96         size = bfd_get_section_size(section);
  97
  98         if (pc < vma || pc >= vma + size)
  99                 return;
 100
 101         a2l->found = bfd_find_nearest_line(abfd, section, a2l->syms, pc - vma,
 102                                            &a2l->filename, &a2l->funcname,
 103                                            &a2l->line);
 104 }
 105
 106 static struct a2l_data *addr2line_init(const char *path)
 107 {
 108         bfd *abfd;
 109         struct a2l_data *a2l = NULL;
 110
 111         abfd = bfd_openr(path, NULL);
 112         if (abfd == NULL)
 113                 return NULL;
 114
 115         if (!bfd_check_format(abfd, bfd_object))
 116                 goto out;
 117
 118         a2l = zalloc(sizeof(*a2l));
 119         if (a2l == NULL)
 120                 goto out;
 121
 122         a2l->abfd = abfd;
 123         a2l->input = strdup(path);
 124         if (a2l->input == NULL)
 125                 goto out;
 126
 127         if (slurp_symtab(abfd, a2l))
 128                 goto out;
 129
 130         return a2l;
 131
 132 out:
 133         if (a2l) {
 134                 zfree((char **)&a2l->input);
 135                 free(a2l);
 136         }
 137         bfd_close(abfd);
 138         return NULL;
 139 }
 140
 141 static void addr2line_cleanup(struct a2l_data *a2l)
 142 {
 143         if (a2l->abfd)
 144                 bfd_close(a2l->abfd);
 145         zfree((char **)&a2l->input);
 146         zfree(&a2l->syms);
 147         free(a2l);
 148 }
 149
 150 static int addr2line(const char *dso_name, u64 addr,
 151                      char **file, unsigned int *line, struct dso *dso)
 152 {
 153         int ret = 0;
 154         struct a2l_data *a2l = dso->a2l;
 155
 156         if (!a2l) {
 157                 dso->a2l = addr2line_init(dso_name);
 158                 a2l = dso->a2l;
 159         }
 160
 161         if (a2l == NULL) {
 162                 pr_warning("addr2line_init failed for %s\n", dso_name);
 163                 return 0;
 164         }
 165
 166         a2l->addr = addr;
 167         a2l->found = false;
 168
 169         bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);
 170
 171         if (a2l->found && a2l->filename) {
 172                 *file = strdup(a2l->filename);
 173                 *line = a2l->line;
 174
 175                 if (*file)
 176                         ret = 1;
 177         }
 178
 179         return ret;
 180 }
 181
 182 void dso__free_a2l(struct dso *dso)
 183 {
 184         struct a2l_data *a2l = dso->a2l;
 185
 186         if (!a2l)
 187                 return;
 188
 189         addr2line_cleanup(a2l);
 190
 191         dso->a2l = NULL;
 192 }
 193
 194 #else /* HAVE_LIBBFD_SUPPORT */
 195
 196 static int addr2line(const char *dso_name, u64 addr,
 197                      char **file, unsigned int *line_nr,
 198                      struct dso *dso __maybe_unused)
 199 {
 200         FILE *fp;
 201         char cmd[PATH_MAX];
 202         char *filename = NULL;
 203         size_t len;
 204         char *sep;
 205         int ret = 0;
 206
 207         scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
 208                   dso_name, addr);
 209
 210         fp = popen(cmd, "r");
 211         if (fp == NULL) {
 212                 pr_warning("popen failed for %s\n", dso_name);
 213                 return 0;
 214         }
 215
 216         if (getline(&filename, &len, fp) < 0 || !len) {
 217                 pr_warning("addr2line has no output for %s\n", dso_name);
 218                 goto out;
 219         }
 220
 221         sep = strchr(filename, '\n');
 222         if (sep)
 223                 *sep = '\0';
 224
 225         if (!strcmp(filename, "??:0")) {
 226                 pr_debug("no debugging info in %s\n", dso_name);
 227                 free(filename);
 228                 goto out;
 229         }
 230
 231         sep = strchr(filename, ':');
 232         if (sep) {
 233                 *sep++ = '\0';
 234                 *file = filename;
 235                 *line_nr = strtoul(sep, NULL, 0);
 236                 ret = 1;
 237         }
 238 out:
 239         pclose(fp);
 240         return ret;
 241 }
 242
 243 void dso__free_a2l(struct dso *dso __maybe_unused)
 244 {
 245 }
 246
 247 #endif /* HAVE_LIBBFD_SUPPORT */
 248
 249 /*
 250  * Number of addr2line failures (without success) before disabling it for that
 251  * dso.
 252  */
 253 #define A2L_FAIL_LIMIT 123
 254
 255 char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 256                   bool show_sym)
 257 {
 258         char *file = NULL;
 259         unsigned line = 0;
 260         char *srcline;
 261         const char *dso_name;
 262
 263         if (!dso->has_srcline)
 264                 goto out;
 265
 266         if (dso->symsrc_filename)
 267                 dso_name = dso->symsrc_filename;
 268         else
 269                 dso_name = dso->long_name;
 270
 271         if (dso_name[0] == '[')
 272                 goto out;
 273
 274         if (!strncmp(dso_name, "/tmp/perf-", 10))
 275                 goto out;
 276
 277         if (!addr2line(dso_name, addr, &file, &line, dso))
 278                 goto out;
 279
 280         if (asprintf(&srcline, "%s:%u", basename(file), line) < 0) {
 281                 free(file);
 282                 goto out;
 283         }
 284
 285         dso->a2l_fails = 0;
 286
 287         free(file);
 288         return srcline;
 289
 290 out:
 291         if (dso->a2l_fails && ++dso->a2l_fails > A2L_FAIL_LIMIT) {
 292                 dso->has_srcline = 0;
 293                 dso__free_a2l(dso);
 294         }
 295         if (sym) {
 296                 if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
 297                                         addr - sym->start) < 0)
 298                         return SRCLINE_UNKNOWN;
 299         } else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
 300                 return SRCLINE_UNKNOWN;
 301         return srcline;
 302 }
 303
 304 void free_srcline(char *srcline)
 305 {
 306         if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
 307                 free(srcline);
 308 }