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);
66 // For some reason, if I try to use it directly, GCC thinks I try to use xbt::backtrace.
67 // I suspect that this symbol is not presented as a regular function in execinfo.h
68 static int gnu_backtrace(simgrid::xbt::Backtrace& bt)
70 return backtrace(bt.data(), bt.size());
77 std::unique_ptr<char, void(*)(void*)> demangle(const char* name)
79 #ifdef __GXX_ABI_VERSION
81 auto res = std::unique_ptr<char, void(*)(void*)>(
82 abi::__cxa_demangle(name, nullptr, nullptr, &status),
87 // We did not manage to resolve this. Probably because this is not a mangled symbol:
90 return std::unique_ptr<char, void(*)(void*)>(xbt_strdup(name), std::free);
95 simgrid::xbt::Backtrace res;
98 int used = gnu_backtrace(res);
100 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
101 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
102 std::fprintf(stderr, "Please go fix the memleaks\n");
111 } // namespace simgrid
116 /** Find the path of the binary file from the name found in argv */
117 static std::string get_binary_path()
119 struct stat stat_buf;
121 if (xbt_binary_name == nullptr)
124 // We found it, we are happy:
125 if (stat(xbt_binary_name, &stat_buf) == 0)
126 return xbt_binary_name;
128 // Not found, look in the PATH:
129 char* path = getenv("PATH");
133 XBT_DEBUG("Looking in the PATH: %s\n", path);
134 std::vector<std::string> path_list;
135 boost::split(path_list, path, boost::is_any_of(":;"));
137 for (std::string const& path_item : path_list) {
138 std::string binary_name = simgrid::xbt::string_printf("%s/%s", path_item.c_str(), xbt_binary_name);
139 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
140 XBT_DEBUG("Looked in the PATH for the binary. %s %s", found ? "Found" : "Not found", binary_name.c_str());
149 std::vector<std::string> resolve_backtrace(const Backtrace& bt)
151 std::vector<std::string> result;
153 #if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
154 // FIXME: This code could be greatly improved/simplified with
155 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
159 if (xbt_binary_name == nullptr)
160 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
162 char** backtrace_syms = backtrace_symbols(bt.data(), bt.size());
163 std::string binary_name = get_binary_path();
165 if (binary_name.empty()) {
166 for (std::size_t i = 1; i < bt.size(); i++) // the first one is not interesting
167 result.push_back(simgrid::xbt::string_printf("%p", bt[i]));
171 // Create the system command for add2line:
172 std::ostringstream stream;
173 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
174 std::vector<std::string> addrs(bt.size());
175 for (std::size_t i = 1; i < bt.size(); i++) { // the first one is not interesting
176 /* retrieve this address */
177 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
179 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
180 char* p = strchr(buff, ']');
182 if (strcmp(buff, "(nil)"))
186 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
187 /* Add it to the command line args */
188 stream << addrs[i] << ' ';
190 std::string cmd = stream.str();
192 /* size (in char) of pointers on this arch */
193 int addr_len = addrs[0].size();
195 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
196 FILE* pipe = popen(cmd.c_str(), "r");
197 xbt_assert(pipe, "Cannot fork addr2line to display the backtrace");
199 /* To read the output of addr2line */
200 char line_func[1024];
202 for (std::size_t i = 1; i < bt.size(); i++) { // The first one is not interesting
203 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
204 if (fgets(line_func, 1024, pipe)) {
205 line_func[strlen(line_func) - 1] = '\0';
207 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
208 strncpy(line_func, "???", 4);
210 if (fgets(line_pos, 1024, pipe)) {
211 line_pos[strlen(line_pos) - 1] = '\0';
213 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
214 strncpy(line_pos, backtrace_syms[i], 1024);
217 if (strcmp("??", line_func) != 0) {
218 auto name = simgrid::xbt::demangle(line_func);
219 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
220 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, bt[i]));
222 /* Damn. The symbol is in a dynamic library. Let's get wild */
224 unsigned long int offset = 0;
227 /* let's look for the offset of this library in our addressing space */
228 std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "/maps";
229 std::ifstream maps(maps_name);
231 XBT_CRITICAL("open(\"%s\") failed: %s", maps_name.c_str(), strerror(errno));
235 unsigned long int addr = std::stoul(addrs[i], &pos, 16);
236 if (pos != addrs[i].length()) {
237 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
239 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
242 unsigned long int first;
243 unsigned long int last;
245 std::string maps_buff;
246 if (not std::getline(maps, maps_buff))
249 XBT_DEBUG("map line: %s", maps_buff.c_str());
251 first = std::stoul(maps_buff, &pos, 16);
252 maps_buff.erase(0, pos + 1);
253 last = std::stoul(maps_buff, nullptr, 16);
254 if (first < addr && addr < last) {
259 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
260 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
267 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
268 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
269 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
273 /* Ok, Found the offset of the maps line containing the searched symbol.
274 We now need to substract this from the address we got from backtrace.
277 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
278 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
280 /* Got it. We have our new address. Let's get the library path and we are set */
281 std::string p(backtrace_syms[i]);
283 /* library path not displayed in the map file either... */
284 snprintf(line_func, 3, "??");
286 size_t p2 = p.find_first_of("( ");
287 if (p2 != std::string::npos)
290 /* Here we go, fire an addr2line up */
291 std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
292 XBT_VERB("Fire another command: '%s'", subcmd.c_str());
293 FILE* subpipe = popen(subcmd.c_str(), "r");
295 xbt_die("Cannot fork addr2line to display the backtrace");
297 if (fgets(line_func, 1024, subpipe)) {
298 line_func[strlen(line_func) - 1] = '\0';
300 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
301 strncpy(line_func, "???", 4);
303 if (fgets(line_pos, 1024, subpipe)) {
304 line_pos[strlen(line_pos) - 1] = '\0';
306 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
307 strncpy(line_pos, backtrace_syms[i], 1024);
312 /* check whether the trick worked */
313 if (strcmp("??", line_func)) {
314 auto name = simgrid::xbt::demangle(line_func);
315 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
316 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, bt[i]));
318 /* damn, nothing to do here. Let's print the raw address */
319 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
320 result.push_back(simgrid::xbt::string_printf("?? at %s", backtrace_syms[i]));
325 /* Mask the bottom of the stack */
326 const char* const breakers[] = {
328 "_ZN7simgrid6kernel7context13ThreadContext7wrapperE", // simgrid::kernel::context::ThreadContext::wrapper
329 "_ZN7simgrid6kernel7context8UContext7wrapperE" // simgrid::kernel::context::UContext::wrapper
331 bool do_break = false;
332 for (const char* b : breakers) {
333 if (strncmp(b, line_func, strlen(b)) == 0) {
342 xbt_free(backtrace_syms);
343 #endif /* ADDR2LINE usable to resolve the backtrace */
348 } // namespace simgrid