michael@0: // vim:ts=8:sw=2:et:
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "leaky.h"
michael@0: 
michael@0: #ifdef USE_BFD
michael@0: #include <stdio.h>
michael@0: #include <string.h>
michael@0: #include <fcntl.h>
michael@0: #include <unistd.h>
michael@0: #include <libgen.h>
michael@0: #include <bfd.h>
michael@0: #include <cxxabi.h>
michael@0: 
michael@0: static bfd *try_debug_file(const char *filename, unsigned long crc32)
michael@0: {
michael@0:   int fd = open(filename, O_RDONLY);
michael@0:   if (fd < 0)
michael@0:     return nullptr;
michael@0: 
michael@0:   unsigned char buf[4*1024];
michael@0:   unsigned long crc = 0;
michael@0: 
michael@0:   while (1) {
michael@0:     ssize_t count = read(fd, buf, sizeof(buf));
michael@0:     if (count <= 0)
michael@0:       break;
michael@0: 
michael@0:     crc = bfd_calc_gnu_debuglink_crc32(crc, buf, count);
michael@0:   }
michael@0: 
michael@0:   close(fd);
michael@0: 
michael@0:   if (crc != crc32)
michael@0:     return nullptr;
michael@0: 
michael@0:   bfd *object = bfd_openr(filename, nullptr);
michael@0:   if (!bfd_check_format(object, bfd_object)) {
michael@0:     bfd_close(object);
michael@0:     return nullptr;
michael@0:   }
michael@0: 
michael@0:   return object;
michael@0: }
michael@0: 
michael@0: static bfd *find_debug_file(bfd *lib, const char *aFileName)
michael@0: {
michael@0:   // check for a separate debug file with symbols
michael@0:   asection *sect = bfd_get_section_by_name(lib, ".gnu_debuglink");
michael@0: 
michael@0:   if (!sect)
michael@0:     return nullptr;
michael@0: 
michael@0:   bfd_size_type debuglinkSize = bfd_section_size (objfile->obfd, sect);
michael@0: 
michael@0:   char *debuglink = new char[debuglinkSize];
michael@0:   bfd_get_section_contents(lib, sect, debuglink, 0, debuglinkSize);
michael@0: 
michael@0:   // crc checksum is aligned to 4 bytes, and after the NUL.
michael@0:   int crc_offset = (int(strlen(debuglink)) & ~3) + 4;
michael@0:   unsigned long crc32 = bfd_get_32(lib, debuglink + crc_offset);
michael@0: 
michael@0:   // directory component
michael@0:   char *dirbuf = strdup(aFileName);
michael@0:   const char *dir = dirname(dirbuf);
michael@0: 
michael@0:   static const char debug_subdir[] = ".debug";
michael@0:   // This is gdb's default global debugging info directory, but gdb can
michael@0:   // be instructed to use a different directory.
michael@0:   static const char global_debug_dir[] = "/usr/lib/debug";
michael@0: 
michael@0:   char *filename =
michael@0:     new char[strlen(global_debug_dir) + strlen(dir) + crc_offset + 3];
michael@0: 
michael@0:   // /path/debuglink
michael@0:   sprintf(filename, "%s/%s", dir, debuglink);
michael@0:   bfd *debugFile = try_debug_file(filename, crc32);
michael@0:   if (!debugFile) {
michael@0: 
michael@0:     // /path/.debug/debuglink
michael@0:     sprintf(filename, "%s/%s/%s", dir, debug_subdir, debuglink);
michael@0:     debugFile = try_debug_file(filename, crc32);
michael@0:     if (!debugFile) {
michael@0: 
michael@0:       // /usr/lib/debug/path/debuglink
michael@0:       sprintf(filename, "%s/%s/%s", global_debug_dir, dir, debuglink);
michael@0:       debugFile = try_debug_file(filename, crc32);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   delete[] filename;
michael@0:   free(dirbuf);
michael@0:   delete[] debuglink;
michael@0: 
michael@0:   return debugFile;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Use an indirect array to avoid copying tons of objects
michael@0: Symbol ** leaky::ExtendSymbols(int num)
michael@0: {
michael@0:   long n = numExternalSymbols + num;
michael@0: 
michael@0:   externalSymbols = (Symbol**)
michael@0:                     realloc(externalSymbols,
michael@0:                             (size_t) (sizeof(externalSymbols[0]) * n));
michael@0:   Symbol *new_array = new Symbol[n];
michael@0:   for (int i = 0; i < num; i++) {
michael@0:     externalSymbols[i + numExternalSymbols] = &new_array[i];
michael@0:   }
michael@0:   lastSymbol = externalSymbols + n;
michael@0:   Symbol **sp = externalSymbols + numExternalSymbols;
michael@0:   numExternalSymbols = n;
michael@0:   return sp;
michael@0: }
michael@0: 
michael@0: #define NEXT_SYMBOL do { sp++; \
michael@0:                          if (sp >= lastSymbol) { \
michael@0:                            sp = ExtendSymbols(16384); \
michael@0:                          } \
michael@0:                        } while (0)
michael@0: 
michael@0: void leaky::ReadSymbols(const char *aFileName, u_long aBaseAddress)
michael@0: {
michael@0:   int initialSymbols = usefulSymbols;
michael@0:   if (nullptr == externalSymbols) {
michael@0:     externalSymbols = (Symbol**) calloc(sizeof(Symbol*),10000);
michael@0:     Symbol *new_array = new Symbol[10000];
michael@0:     for (int i = 0; i < 10000; i++) {
michael@0:       externalSymbols[i] = &new_array[i];
michael@0:     }
michael@0:     numExternalSymbols = 10000;
michael@0:   }
michael@0:   Symbol** sp = externalSymbols + usefulSymbols;
michael@0:   lastSymbol = externalSymbols + numExternalSymbols;
michael@0: 
michael@0:   // Create a dummy symbol for the library so, if it doesn't have any
michael@0:   // symbols, we show it by library.
michael@0:   (*sp)->Init(aFileName, aBaseAddress);
michael@0:   NEXT_SYMBOL;
michael@0: 
michael@0:   bfd_boolean kDynamic = (bfd_boolean) false;
michael@0: 
michael@0:   static int firstTime = 1;
michael@0:   if (firstTime) {
michael@0:     firstTime = 0;
michael@0:     bfd_init ();
michael@0:   }
michael@0: 
michael@0:   bfd* lib = bfd_openr(aFileName, nullptr);
michael@0:   if (nullptr == lib) {
michael@0:     return;
michael@0:   }
michael@0:   if (!bfd_check_format(lib, bfd_object)) {
michael@0:     bfd_close(lib);
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   bfd *symbolFile = find_debug_file(lib, aFileName);
michael@0: 
michael@0:   // read mini symbols
michael@0:   PTR minisyms;
michael@0:   unsigned int size;
michael@0:   long symcount = 0;
michael@0: 
michael@0:   if (symbolFile) {
michael@0:     symcount = bfd_read_minisymbols(symbolFile, kDynamic, &minisyms, &size);
michael@0:     if (symcount == 0) {
michael@0:       bfd_close(symbolFile);
michael@0:     } else {
michael@0:       bfd_close(lib);
michael@0:     }
michael@0:   }
michael@0:   if (symcount == 0) {
michael@0:     symcount = bfd_read_minisymbols(lib, kDynamic, &minisyms, &size);
michael@0:     if (symcount == 0) {
michael@0:       // symtab is empty; try dynamic symbols
michael@0:       kDynamic = (bfd_boolean) true;
michael@0:       symcount = bfd_read_minisymbols(lib, kDynamic, &minisyms, &size);
michael@0:     }
michael@0:     symbolFile = lib;
michael@0:   }
michael@0: 
michael@0:   asymbol* store;
michael@0:   store = bfd_make_empty_symbol(symbolFile);
michael@0: 
michael@0:   // Scan symbols
michael@0:   size_t demangle_buffer_size = 128;
michael@0:   char *demangle_buffer = (char*) malloc(demangle_buffer_size);
michael@0:   bfd_byte* from = (bfd_byte *) minisyms;
michael@0:   bfd_byte* fromend = from + symcount * size;
michael@0:   for (; from < fromend; from += size) {
michael@0:     asymbol *sym;
michael@0:     sym = bfd_minisymbol_to_symbol(symbolFile, kDynamic, (const PTR) from, store);
michael@0: 
michael@0:     symbol_info syminfo;
michael@0:     bfd_get_symbol_info (symbolFile, sym, &syminfo);
michael@0: 
michael@0: //    if ((syminfo.type == 'T') || (syminfo.type == 't')) {
michael@0:       const char* nm = bfd_asymbol_name(sym);
michael@0:       if (nm && nm[0]) {
michael@0:         char* dnm = nullptr;
michael@0:         if (strncmp("__thunk", nm, 7)) {
michael@0:           dnm =
michael@0:             abi::__cxa_demangle(nm, demangle_buffer, &demangle_buffer_size, 0);
michael@0:           if (dnm) {
michael@0:             demangle_buffer = dnm;
michael@0:           }
michael@0:         }
michael@0:         (*sp)->Init(dnm ? dnm : nm, syminfo.value + aBaseAddress);
michael@0:         NEXT_SYMBOL;
michael@0:       }
michael@0: //    }
michael@0:   }
michael@0: 
michael@0:   free(demangle_buffer);
michael@0:   demangle_buffer = nullptr;
michael@0: 
michael@0:   bfd_close(symbolFile);
michael@0: 
michael@0:   int interesting = sp - externalSymbols;
michael@0:   if (!quiet) {
michael@0:     printf("%s provided %d symbols\n", aFileName,
michael@0:            interesting - initialSymbols);
michael@0:   }
michael@0:   usefulSymbols = interesting;
michael@0: }
michael@0: 
michael@0: #endif /* USE_BFD */