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
22 #ifdef HAVE_EXECINFO_H
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)
42 std::vector<std::string> backtrace = simgrid::xbt::resolve_backtrace(loc, count);
43 if (backtrace.empty()) {
44 fprintf(stderr, "(backtrace not set)\n");
47 fprintf(stderr, "Backtrace (displayed in process %s):\n", SIMIX_process_self_get_name());
48 for (std::string const& s : backtrace) {
49 if (startWith(s, "xbt_backtrace_display_current"))
52 std::fprintf(stderr, "---> '%s'\n", s.c_str());
53 if (startWith(s, "SIMIX_simcall_handle") ||
54 startWith(s, "simgrid::xbt::MainFunction") /* main used with thread factory */)
58 XBT_ERROR("Cannot display backtrace when compiled without libunwind.");
62 /** @brief show the backtrace of the current point (lovely while debugging) */
63 void xbt_backtrace_display_current()
65 const std::size_t size = 10;
66 xbt_backtrace_location_t bt[size];
67 size_t used = xbt_backtrace_current(bt, size);
68 xbt_backtrace_display(bt, used);
74 std::unique_ptr<char, void(*)(void*)> demangle(const char* name)
76 #ifdef __GXX_ABI_VERSION
78 auto res = std::unique_ptr<char, void(*)(void*)>(
79 abi::__cxa_demangle(name, nullptr, nullptr, &status),
84 // We did not manage to resolve this. Probably because this is not a mangled symbol:
87 return std::unique_ptr<char, void(*)(void*)>(xbt_strdup(name), std::free);
92 const std::size_t size = 10;
93 xbt_backtrace_location_t loc[size];
94 size_t used = xbt_backtrace_current(loc, size);
95 return Backtrace(loc, loc + used);
101 #if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
102 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
104 std::size_t used = backtrace(loc, count);
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");
117 /** Find the path of the binary file from the name found in argv */
118 static std::string get_binary_path()
120 struct stat stat_buf;
122 if (xbt_binary_name == nullptr)
125 // We found it, we are happy:
126 if (stat(xbt_binary_name, &stat_buf) == 0)
127 return xbt_binary_name;
129 // Not found, look in the PATH:
130 char* path = getenv("PATH");
133 XBT_DEBUG("Looking in the PATH: %s\n", path);
134 std::vector<std::string> path_list;
135 // TODO, on Windows, this is ";"
136 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 // FIXME: This code could be greatly improved/simplifyied with
150 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
151 std::vector<std::string> resolve_backtrace(xbt_backtrace_location_t const* loc, std::size_t count)
153 std::vector<std::string> result;
158 if (xbt_binary_name == nullptr)
159 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
161 // Drop the first one:
165 char** backtrace_syms = backtrace_symbols(loc, count);
166 std::string binary_name = get_binary_path();
168 if (binary_name.empty()) {
169 for (std::size_t i = 0; i < count; i++)
170 result.push_back(simgrid::xbt::string_printf("%p", loc[i]));
174 // Create the system command for add2line:
175 std::ostringstream stream;
176 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
177 std::vector<std::string> addrs(count);
178 for (std::size_t i = 0; i < count; i++) {
179 /* retrieve this address */
180 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
182 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
183 char* p = strchr(buff, ']');
185 if (strcmp(buff, "(nil)"))
189 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
190 /* Add it to the command line args */
191 stream << addrs[i] << ' ';
193 std::string cmd = stream.str();
195 /* size (in char) of pointers on this arch */
196 int addr_len = addrs[0].size();
198 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
199 FILE* pipe = popen(cmd.c_str(), "r");
200 xbt_assert(pipe, "Cannot fork addr2line to display the backtrace");
202 /* To read the output of addr2line */
203 char line_func[1024];
205 for (std::size_t i = 0; i < count; i++) {
206 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
207 if (fgets(line_func, 1024, pipe)) {
208 line_func[strlen(line_func) - 1] = '\0';
210 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
211 strncpy(line_func, "???", 4);
213 if (fgets(line_pos, 1024, pipe)) {
214 line_pos[strlen(line_pos) - 1] = '\0';
216 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
217 strncpy(line_pos, backtrace_syms[i], 1024);
220 if (strcmp("??", line_func) != 0) {
221 auto name = simgrid::xbt::demangle(line_func);
222 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
223 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
225 /* Damn. The symbol is in a dynamic library. Let's get wild */
227 unsigned long int offset = 0;
230 /* let's look for the offset of this library in our addressing space */
231 std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "/maps";
232 std::ifstream maps(maps_name);
234 XBT_CRITICAL("open(\"%s\") failed: %s", maps_name.c_str(), strerror(errno));
238 unsigned long int addr = std::stoul(addrs[i], &pos, 16);
239 if (pos != addrs[i].length()) {
240 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
242 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
245 unsigned long int first;
246 unsigned long int last;
248 std::string maps_buff;
249 if (not std::getline(maps, maps_buff))
252 XBT_DEBUG("map line: %s", maps_buff.c_str());
254 first = std::stoul(maps_buff, &pos, 16);
255 maps_buff.erase(0, pos + 1);
256 last = std::stoul(maps_buff, nullptr, 16);
257 if (first < addr && addr < last) {
262 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
263 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
270 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
271 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
272 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
276 /* Ok, Found the offset of the maps line containing the searched symbol.
277 We now need to substract this from the address we got from backtrace.
280 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
281 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
283 /* Got it. We have our new address. Let's get the library path and we are set */
284 std::string p(backtrace_syms[i]);
286 /* library path not displayed in the map file either... */
287 snprintf(line_func, 3, "??");
289 size_t p2 = p.find_first_of("( ");
290 if (p2 != std::string::npos)
293 /* Here we go, fire an addr2line up */
294 std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
295 XBT_VERB("Fire another command: '%s'", subcmd.c_str());
296 FILE* subpipe = popen(subcmd.c_str(), "r");
298 xbt_die("Cannot fork addr2line to display the backtrace");
300 if (fgets(line_func, 1024, subpipe)) {
301 line_func[strlen(line_func) - 1] = '\0';
303 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
304 strncpy(line_func, "???", 4);
306 if (fgets(line_pos, 1024, subpipe)) {
307 line_pos[strlen(line_pos) - 1] = '\0';
309 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
310 strncpy(line_pos, backtrace_syms[i], 1024);
315 /* check whether the trick worked */
316 if (strcmp("??", line_func)) {
317 auto name = simgrid::xbt::demangle(line_func);
318 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
319 result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
321 /* damn, nothing to do here. Let's print the raw address */
322 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
323 result.push_back(simgrid::xbt::string_printf("?? at %s", backtrace_syms[i]));
328 /* Mask the bottom of the stack */
329 const char* const breakers[] = {
331 "_ZN7simgrid6kernel7context13ThreadContext7wrapperE", // simgrid::kernel::context::ThreadContext::wrapper
332 "_ZN7simgrid6kernel7context8UContext7wrapperE" // simgrid::kernel::context::UContext::wrapper
334 bool do_break = false;
335 for (const char* b : breakers) {
336 if (strncmp(b, line_func, strlen(b)) == 0) {
345 free(backtrace_syms);
350 } // namespace simgrid
351 #else /* We must use dummy backtraces because of missing dependencies */
352 /* create a backtrace in the given exception */
353 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, size_t count)
361 std::vector<std::string> resolve_backtrace(xbt_backtrace_location_t const* loc, std::size_t count)
363 return std::vector<std::string>();
367 } // namespace simgrid