1 /* Copyright (c) 2005-2018. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "src/internal_config.h"
16 #include <boost/algorithm/string.hpp>
18 // Try to detect and use the C++ itanium ABI for name demangling:
19 #ifdef __GXX_ABI_VERSION
26 #include "simgrid/simix.h" /* SIMIX_process_self_get_name() */
27 #include <xbt/backtrace.hpp>
29 #include <xbt/string.hpp>
30 #include <xbt/sysdep.h>
32 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_backtrace, xbt, "Backtrace");
34 static bool startWith(std::string str, const char* prefix)
36 return strncmp(str.c_str(), prefix, strlen(prefix)) == 0;
39 void xbt_backtrace_display(const simgrid::xbt::Backtrace& bt)
41 std::vector<std::string> backtrace = simgrid::xbt::resolve_backtrace(bt);
42 if (backtrace.empty()) {
43 fprintf(stderr, "(backtrace not set -- maybe unavailable on this architecture?)\n");
46 fprintf(stderr, "Backtrace (displayed in process %s):\n", SIMIX_process_self_get_name());
47 for (std::string const& s : backtrace) {
48 if (startWith(s, "xbt_backtrace_display_current"))
51 std::fprintf(stderr, "---> '%s'\n", s.c_str());
52 if (startWith(s, "SIMIX_simcall_handle") ||
53 startWith(s, "simgrid::xbt::MainFunction") /* main used with thread factory */)
58 /** @brief show the backtrace of the current point (lovely while debugging) */
59 void xbt_backtrace_display_current()
61 simgrid::xbt::Backtrace bt = simgrid::xbt::Backtrace();
62 xbt_backtrace_display(bt);
68 std::unique_ptr<char, void(*)(void*)> demangle(const char* name)
70 #ifdef __GXX_ABI_VERSION
72 auto res = std::unique_ptr<char, void(*)(void*)>(
73 abi::__cxa_demangle(name, nullptr, nullptr, &status),
78 // We did not manage to resolve this. Probably because this is not a mangled symbol:
81 return std::unique_ptr<char, void(*)(void*)>(xbt_strdup(name), std::free);
88 void ref() { refcount_++; }
92 return refcount_ == 0;
95 std::vector<void*> frames;
99 Backtrace::Backtrace()
102 impl_ = new BacktraceImpl();
103 impl_->frames.resize(15);
104 int used = backtrace(impl_->frames.data(), impl_->frames.size());
106 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
107 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
108 std::fprintf(stderr, "Please go fix the memleaks\n");
111 impl_->frames.shrink_to_fit();
114 Backtrace::Backtrace(const Backtrace& bt)
120 Backtrace::~Backtrace()
122 if (impl_->unref()) {
129 } // namespace simgrid
134 /** Find the path of the binary file from the name found in argv */
135 static std::string get_binary_path()
137 struct stat stat_buf;
139 if (xbt_binary_name == nullptr)
142 // We found it, we are happy:
143 if (stat(xbt_binary_name, &stat_buf) == 0)
144 return xbt_binary_name;
146 // Not found, look in the PATH:
147 char* path = getenv("PATH");
151 XBT_DEBUG("Looking in the PATH: %s\n", path);
152 std::vector<std::string> path_list;
153 boost::split(path_list, path, boost::is_any_of(":;"));
155 for (std::string const& path_item : path_list) {
156 std::string binary_name = simgrid::xbt::string_printf("%s/%s", path_item.c_str(), xbt_binary_name);
157 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
158 XBT_DEBUG("Looked in the PATH for the binary. %s %s", found ? "Found" : "Not found", binary_name.c_str());
167 std::vector<std::string> resolve_backtrace(const Backtrace& bt)
169 std::vector<std::string> result;
171 #if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
172 // FIXME: This code could be greatly improved/simplified with
173 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
174 if (bt.impl_->frames.size() == 0)
177 if (xbt_binary_name == nullptr)
178 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
180 char** backtrace_syms = backtrace_symbols(bt.impl_->frames.data(), bt.impl_->frames.size());
181 std::string binary_name = get_binary_path();
183 if (binary_name.empty()) {
184 for (std::size_t i = 1; i < bt.impl_->frames.size(); i++) // the first one is not interesting
185 result.push_back(simgrid::xbt::string_printf("%p", bt.impl_->frames[i]));
189 // Create the system command for add2line:
190 std::ostringstream stream;
191 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
192 std::vector<std::string> addrs(bt.impl_->frames.size());
193 for (std::size_t i = 1; i < bt.impl_->frames.size(); i++) { // the first one is not interesting
194 /* retrieve this address */
195 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
197 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
198 char* p = strchr(buff, ']');
200 if (strcmp(buff, "(nil)"))
204 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
205 /* Add it to the command line args */
206 stream << addrs[i] << ' ';
208 std::string cmd = stream.str();
210 /* size (in char) of pointers on this arch */
211 int addr_len = addrs[0].size();
213 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
214 FILE* pipe = popen(cmd.c_str(), "r");
215 xbt_assert(pipe, "Cannot fork addr2line to display the backtrace");
217 /* To read the output of addr2line */
218 char line_func[1024];
220 for (std::size_t i = 1; i < bt.impl_->frames.size(); i++) { // The first one is not interesting
221 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
222 if (fgets(line_func, 1024, pipe)) {
223 line_func[strlen(line_func) - 1] = '\0';
225 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
226 strncpy(line_func, "???", 4);
228 if (fgets(line_pos, 1024, pipe)) {
229 line_pos[strlen(line_pos) - 1] = '\0';
231 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
232 strncpy(line_pos, backtrace_syms[i], 1024);
235 if (strcmp("??", line_func) != 0) {
236 auto name = simgrid::xbt::demangle(line_func);
237 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
238 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, bt.impl_->frames[i]));
240 /* Damn. The symbol is in a dynamic library. Let's get wild */
242 unsigned long int offset = 0;
245 /* let's look for the offset of this library in our addressing space */
246 std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "/maps";
247 std::ifstream maps(maps_name);
249 XBT_CRITICAL("open(\"%s\") failed: %s", maps_name.c_str(), strerror(errno));
253 unsigned long int addr = std::stoul(addrs[i], &pos, 16);
254 if (pos != addrs[i].length()) {
255 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
257 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
260 unsigned long int first;
261 unsigned long int last;
263 std::string maps_buff;
264 if (not std::getline(maps, maps_buff))
267 XBT_DEBUG("map line: %s", maps_buff.c_str());
269 first = std::stoul(maps_buff, &pos, 16);
270 maps_buff.erase(0, pos + 1);
271 last = std::stoul(maps_buff, nullptr, 16);
272 if (first < addr && addr < last) {
277 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
278 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
285 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
286 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
287 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
291 /* Ok, Found the offset of the maps line containing the searched symbol.
292 We now need to substract this from the address we got from backtrace.
295 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
296 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
298 /* Got it. We have our new address. Let's get the library path and we are set */
299 std::string p(backtrace_syms[i]);
301 /* library path not displayed in the map file either... */
302 snprintf(line_func, 3, "??");
304 size_t p2 = p.find_first_of("( ");
305 if (p2 != std::string::npos)
308 /* Here we go, fire an addr2line up */
309 std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
310 XBT_VERB("Fire another command: '%s'", subcmd.c_str());
311 FILE* subpipe = popen(subcmd.c_str(), "r");
313 xbt_die("Cannot fork addr2line to display the backtrace");
315 if (fgets(line_func, 1024, subpipe)) {
316 line_func[strlen(line_func) - 1] = '\0';
318 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
319 strncpy(line_func, "???", 4);
321 if (fgets(line_pos, 1024, subpipe)) {
322 line_pos[strlen(line_pos) - 1] = '\0';
324 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
325 strncpy(line_pos, backtrace_syms[i], 1024);
330 /* check whether the trick worked */
331 if (strcmp("??", line_func)) {
332 auto name = simgrid::xbt::demangle(line_func);
333 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
334 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, bt.impl_->frames[i]));
336 /* damn, nothing to do here. Let's print the raw address */
337 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
338 result.push_back(simgrid::xbt::string_printf("?? at %s", backtrace_syms[i]));
343 /* Mask the bottom of the stack */
344 const char* const breakers[] = {
346 "_ZN7simgrid6kernel7context13ThreadContext7wrapperE", // simgrid::kernel::context::ThreadContext::wrapper
347 "_ZN7simgrid6kernel7context8UContext7wrapperE" // simgrid::kernel::context::UContext::wrapper
349 bool do_break = false;
350 for (const char* b : breakers) {
351 if (strncmp(b, line_func, strlen(b)) == 0) {
360 xbt_free(backtrace_syms);
361 #endif /* ADDR2LINE usable to resolve the backtrace */
366 } // namespace simgrid