1 /* backtrace_linux - backtrace displaying on linux platform */
2 /* This file is included by ex.cpp on need (have execinfo.h, popen & addrline)*/
4 /* Copyright (c) 2008-2017. The SimGrid Team. All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include <boost/algorithm/string.hpp>
19 /* This file is to be included in ex.cpp, so the following headers are not mandatory, but it's to make sure that eclipse see them too */
20 #include <xbt/string.hpp>
21 #include <xbt/backtrace.hpp>
24 #include "xbt/module.h" /* xbt_binary_name */
25 #include "src/xbt_modinter.h" /* backtrace initialization headers */
27 #define UNW_LOCAL_ONLY
28 #include <libunwind.h>
30 /* end of "useless" inclusions */
32 extern char **environ; /* the environment, as specified by the opengroup */
41 static _Unwind_Reason_Code
42 backtrace_helper (struct _Unwind_Context *ctx, void *a)
44 struct trace_arg *arg = (struct trace_arg *) a;
46 /* We are first called with address in the __backtrace function.
50 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
52 /* Check whether we make any progress. */
53 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
54 return _URC_END_OF_STACK;
56 if (++arg->cnt == arg->size)
57 return _URC_END_OF_STACK;
58 return _URC_NO_REASON;
61 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
63 * See http://people.irisa.fr/Martin.Quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
64 * for the motivation behind this function
67 int xbt_backtrace_no_malloc(void **array, int size) {
69 for(i=0; i < size; i++)
78 _Unwind_Backtrace(backtrace_helper, &arg);
80 /* _Unwind_Backtrace on IA-64 seems to put nullptr address above
81 _start. Fix it up here. */
82 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == nullptr)
84 return arg.cnt != -1 ? arg.cnt : 0;
87 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
89 std::size_t used = backtrace(loc, count);
91 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
92 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
93 std::fprintf(stderr, "Please go fix the memleaks\n");
102 /** Find the path of the binary file from the name found in argv */
103 static std::string get_binary_path()
105 struct stat stat_buf;
107 if (xbt_binary_name == nullptr)
110 // We found it, we are happy:
111 if (stat(xbt_binary_name, &stat_buf) == 0)
112 return xbt_binary_name;
114 // Not found, look in the PATH:
115 char* path = getenv("PATH");
118 XBT_DEBUG("Looking in the PATH: %s\n", path);
119 std::vector<std::string> path_list;
120 // TODO, on Windows, this is ";"
121 boost::split(path_list, path, boost::is_any_of(":"));
122 for (std::string const& path_item : path_list) {
123 std::string binary_name = simgrid::xbt::string_printf(
124 "%s/%s", path_item.c_str(), xbt_binary_name);
125 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
126 XBT_DEBUG("Looked in the PATH for the binary. %s %s",
127 found ? "Found" : "Not found",
128 binary_name.c_str());
137 //FIXME: This code could be greatly improved/simplifyied with
138 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
139 std::vector<std::string> resolveBacktrace(
140 xbt_backtrace_location_t const* loc, std::size_t count)
142 std::vector<std::string> result;
147 if (xbt_binary_name == nullptr)
148 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
150 // Drop the first one:
153 char** backtrace_syms = backtrace_symbols(loc, count);
154 std::string binary_name = get_binary_path();
156 if (binary_name.empty()) {
157 for (std::size_t i = 0; i < count; i++)
158 result.push_back(simgrid::xbt::string_printf("%p", loc[i]));
162 // Create the system command for add2line:
163 std::ostringstream stream;
164 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
165 std::vector<std::string> addrs(count);
166 for (std::size_t i = 0; i < count; i++) {
167 /* retrieve this address */
168 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
170 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
171 char* p = strchr(buff, ']');
173 if (strcmp(buff, "(nil)"))
177 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
178 /* Add it to the command line args */
179 stream << addrs[i] << ' ';
181 std::string cmd = stream.str();
183 /* size (in char) of pointers on this arch */
184 int addr_len = addrs[0].size();
186 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
187 FILE* pipe = popen(cmd.c_str(), "r");
189 xbt_die("Cannot fork addr2line to display the backtrace");
192 /* To read the output of addr2line */
193 char line_func[1024];
195 for (std::size_t i = 0; i < count; i++) {
196 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
197 if (fgets(line_func, 1024, pipe)) {
198 line_func[strlen(line_func) - 1] = '\0';
200 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
201 strncpy(line_func, "???",3);
203 if (fgets(line_pos, 1024, pipe)) {
204 line_pos[strlen(line_pos) - 1] = '\0';
206 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
207 strncpy(line_pos, backtrace_syms[i],1024);
210 if (strcmp("??", line_func) != 0) {
211 auto name = simgrid::xbt::demangle(line_func);
212 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
213 result.push_back(simgrid::xbt::string_printf(
214 "%s at %s, %p", name.get(), line_pos, loc[i]
217 /* Damn. The symbol is in a dynamic library. Let's get wild */
220 unsigned long int offset = 0;
224 /* let's look for the offset of this library in our addressing space */
225 char* maps_name = bprintf("/proc/%d/maps", (int) getpid());
226 FILE* maps = fopen(maps_name, "r");
228 unsigned long int addr = strtoul(addrs[i].c_str(), &p, 16);
230 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
232 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
235 unsigned long int first;
236 unsigned long int last;
238 if (fgets(maps_buff, 512, maps) == nullptr)
241 maps_buff[strlen(maps_buff) - 1] = '\0';
242 XBT_DEBUG("map line: %s", maps_buff);
244 sscanf(maps_buff, "%lx", &first);
245 p = strchr(maps_buff, '-') + 1;
246 sscanf(p, "%lx", &last);
247 if (first < addr && addr < last) {
252 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
253 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
261 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
262 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
263 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
267 /* Ok, Found the offset of the maps line containing the searched symbol.
268 We now need to substract this from the address we got from backtrace.
271 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
272 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
274 /* Got it. We have our new address. Let's get the library path and we are set */
275 p = xbt_strdup(backtrace_syms[i]);
277 /* library path not displayed in the map file either... */
279 snprintf(line_func,3, "??");
281 char* p2 = strrchr(p, '(');
284 p2 = strrchr(p, ' ');
288 /* Here we go, fire an addr2line up */
289 char* subcmd = bprintf("%s -f -e %s %s", ADDR2LINE, p, addrs[i].c_str());
291 XBT_VERB("Fire a new command: '%s'", subcmd);
292 FILE* subpipe = popen(subcmd, "r");
294 xbt_die("Cannot fork addr2line to display the backtrace");
296 if (fgets(line_func, 1024, subpipe)) {
297 line_func[strlen(line_func) - 1] = '\0';
299 XBT_VERB("Cannot read result of subcommand %s", subcmd);
300 strncpy(line_func, "???",3);
302 if (fgets(line_pos, 1024, subpipe)) {
303 line_pos[strlen(line_pos) - 1] = '\0';
305 XBT_VERB("Cannot read result of subcommand %s", subcmd);
306 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(
317 "%s at %s, %p", name.get(), line_pos, loc[i]));
319 /* damn, nothing to do here. Let's print the raw address */
320 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
321 result.push_back(simgrid::xbt::string_printf(
322 "?? at %s", backtrace_syms[i]));
327 /* Mask the bottom of the stack */
328 if (not strncmp("main", line_func, strlen("main")) ||
329 not strncmp("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper")) ||
330 not strncmp("smx_ctx_sysv_wrapper", line_func, strlen("smx_ctx_sysv_wrapper")))
334 free(backtrace_syms);
342 int xbt_libunwind_backtrace(void** bt, int size){
343 for (int i = 0; i < size; i++)
349 unw_getcontext (&uc);
350 unw_init_local (&c, &uc);
355 for (i = 0; unw_step(&c) >= 0 && i < size; i++) {
357 unw_get_reg(&c, UNW_REG_IP, &ip);
358 bt[i] = (void*)(long)ip;