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(xbt_backtrace_location_t* loc, std::size_t count)
41 std::vector<std::string> backtrace = simgrid::xbt::resolve_backtrace(loc, count);
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 const std::size_t size = 10;
62 xbt_backtrace_location_t bt[size];
63 size_t used = xbt_backtrace_current(bt, size);
64 xbt_backtrace_display(bt, used);
70 std::unique_ptr<char, void(*)(void*)> demangle(const char* name)
72 #ifdef __GXX_ABI_VERSION
74 auto res = std::unique_ptr<char, void(*)(void*)>(
75 abi::__cxa_demangle(name, nullptr, nullptr, &status),
80 // We did not manage to resolve this. Probably because this is not a mangled symbol:
83 return std::unique_ptr<char, void(*)(void*)>(xbt_strdup(name), std::free);
88 const std::size_t size = 10;
89 xbt_backtrace_location_t loc[size];
90 size_t used = xbt_backtrace_current(loc, size);
91 return Backtrace(loc, loc + used);
97 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
101 used = backtrace(loc, count);
103 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
104 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
105 std::fprintf(stderr, "Please go fix the memleaks\n");
115 /** Find the path of the binary file from the name found in argv */
116 static std::string get_binary_path()
118 struct stat stat_buf;
120 if (xbt_binary_name == nullptr)
123 // We found it, we are happy:
124 if (stat(xbt_binary_name, &stat_buf) == 0)
125 return xbt_binary_name;
127 // Not found, look in the PATH:
128 char* path = getenv("PATH");
131 XBT_DEBUG("Looking in the PATH: %s\n", path);
132 std::vector<std::string> path_list;
133 // TODO, on Windows, this is ";"
134 boost::split(path_list, path, boost::is_any_of(":"));
135 for (std::string const& path_item : path_list) {
136 std::string binary_name = simgrid::xbt::string_printf("%s/%s", path_item.c_str(), xbt_binary_name);
137 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
138 XBT_DEBUG("Looked in the PATH for the binary. %s %s", found ? "Found" : "Not found", binary_name.c_str());
147 std::vector<std::string> resolve_backtrace(xbt_backtrace_location_t const* loc, std::size_t count)
149 std::vector<std::string> result;
151 #if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
152 // FIXME: This code could be greatly improved/simplified with
153 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
157 if (xbt_binary_name == nullptr)
158 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
160 // Drop the first one:
164 char** backtrace_syms = backtrace_symbols(loc, count);
165 std::string binary_name = get_binary_path();
167 if (binary_name.empty()) {
168 for (std::size_t i = 0; i < count; i++)
169 result.push_back(simgrid::xbt::string_printf("%p", loc[i]));
173 // Create the system command for add2line:
174 std::ostringstream stream;
175 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
176 std::vector<std::string> addrs(count);
177 for (std::size_t i = 0; i < count; i++) {
178 /* retrieve this address */
179 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
181 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
182 char* p = strchr(buff, ']');
184 if (strcmp(buff, "(nil)"))
188 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
189 /* Add it to the command line args */
190 stream << addrs[i] << ' ';
192 std::string cmd = stream.str();
194 /* size (in char) of pointers on this arch */
195 int addr_len = addrs[0].size();
197 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
198 FILE* pipe = popen(cmd.c_str(), "r");
199 xbt_assert(pipe, "Cannot fork addr2line to display the backtrace");
201 /* To read the output of addr2line */
202 char line_func[1024];
204 for (std::size_t i = 0; i < count; i++) {
205 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
206 if (fgets(line_func, 1024, pipe)) {
207 line_func[strlen(line_func) - 1] = '\0';
209 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
210 strncpy(line_func, "???", 4);
212 if (fgets(line_pos, 1024, pipe)) {
213 line_pos[strlen(line_pos) - 1] = '\0';
215 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
216 strncpy(line_pos, backtrace_syms[i], 1024);
219 if (strcmp("??", line_func) != 0) {
220 auto name = simgrid::xbt::demangle(line_func);
221 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
222 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
224 /* Damn. The symbol is in a dynamic library. Let's get wild */
226 unsigned long int offset = 0;
229 /* let's look for the offset of this library in our addressing space */
230 std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "/maps";
231 std::ifstream maps(maps_name);
233 XBT_CRITICAL("open(\"%s\") failed: %s", maps_name.c_str(), strerror(errno));
237 unsigned long int addr = std::stoul(addrs[i], &pos, 16);
238 if (pos != addrs[i].length()) {
239 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
241 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
244 unsigned long int first;
245 unsigned long int last;
247 std::string maps_buff;
248 if (not std::getline(maps, maps_buff))
251 XBT_DEBUG("map line: %s", maps_buff.c_str());
253 first = std::stoul(maps_buff, &pos, 16);
254 maps_buff.erase(0, pos + 1);
255 last = std::stoul(maps_buff, nullptr, 16);
256 if (first < addr && addr < last) {
261 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
262 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
269 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
270 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
271 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
275 /* Ok, Found the offset of the maps line containing the searched symbol.
276 We now need to substract this from the address we got from backtrace.
279 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
280 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
282 /* Got it. We have our new address. Let's get the library path and we are set */
283 std::string p(backtrace_syms[i]);
285 /* library path not displayed in the map file either... */
286 snprintf(line_func, 3, "??");
288 size_t p2 = p.find_first_of("( ");
289 if (p2 != std::string::npos)
292 /* Here we go, fire an addr2line up */
293 std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
294 XBT_VERB("Fire another command: '%s'", subcmd.c_str());
295 FILE* subpipe = popen(subcmd.c_str(), "r");
297 xbt_die("Cannot fork addr2line to display the backtrace");
299 if (fgets(line_func, 1024, subpipe)) {
300 line_func[strlen(line_func) - 1] = '\0';
302 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
303 strncpy(line_func, "???", 4);
305 if (fgets(line_pos, 1024, subpipe)) {
306 line_pos[strlen(line_pos) - 1] = '\0';
308 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
309 strncpy(line_pos, backtrace_syms[i], 1024);
314 /* check whether the trick worked */
315 if (strcmp("??", line_func)) {
316 auto name = simgrid::xbt::demangle(line_func);
317 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
318 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
320 /* damn, nothing to do here. Let's print the raw address */
321 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
322 result.push_back(simgrid::xbt::string_printf("?? at %s", backtrace_syms[i]));
327 /* Mask the bottom of the stack */
328 const char* const breakers[] = {
330 "_ZN7simgrid6kernel7context13ThreadContext7wrapperE", // simgrid::kernel::context::ThreadContext::wrapper
331 "_ZN7simgrid6kernel7context8UContext7wrapperE" // simgrid::kernel::context::UContext::wrapper
333 bool do_break = false;
334 for (const char* b : breakers) {
335 if (strncmp(b, line_func, strlen(b)) == 0) {
344 free(backtrace_syms);
345 #endif /* ADDR2LINE usable to resolve the backtrace */
350 } // namespace simgrid