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) 2008-2016. The SimGrid Team.
5 * All rights reserved. */
7 /* This program is free software; you can redistribute it and/or modify it
8 * under the terms of the license (GNU LGPL) which comes with this package. */
14 #include <boost/algorithm/string.hpp>
20 /* 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 */
21 #include <xbt/string.hpp>
22 #include <xbt/backtrace.hpp>
24 #include "src/xbt/ex_interface.h"
27 #include "xbt/module.h" /* xbt_binary_name */
28 #include "src/xbt_modinter.h" /* backtrace initialization headers */
30 #define UNW_LOCAL_ONLY
31 #include <libunwind.h>
33 /* end of "useless" inclusions */
35 extern char **environ; /* the environment, as specified by the opengroup */
37 /* Module creation/destruction: nothing to do on linux */
38 void xbt_backtrace_preinit(void)
42 void xbt_backtrace_postexit(void)
52 static _Unwind_Reason_Code
53 backtrace_helper (struct _Unwind_Context *ctx, void *a)
55 struct trace_arg *arg = (struct trace_arg *) a;
57 /* We are first called with address in the __backtrace function.
61 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
63 /* Check whether we make any progress. */
64 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
65 return _URC_END_OF_STACK;
67 if (++arg->cnt == arg->size)
68 return _URC_END_OF_STACK;
69 return _URC_NO_REASON;
72 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
74 * See http://webloria.loria.fr/~quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
75 * for the motivation behind this function
78 int xbt_backtrace_no_malloc(void **array, int size) {
80 for(i=0; i < size; i++)
89 _Unwind_Backtrace(backtrace_helper, &arg);
91 /* _Unwind_Backtrace on IA-64 seems to put NULL address above
92 _start. Fix it up here. */
93 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
95 return arg.cnt != -1 ? arg.cnt : 0;
98 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
100 std::size_t used = backtrace(loc, count);
102 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
103 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
104 std::fprintf(stderr, "Please go fix the memleaks\n");
113 /** Find the path of the binary file from the name found in argv */
114 static std::string get_binary_path()
116 struct stat stat_buf;
118 if (xbt_binary_name == nullptr)
121 // We found it, we are happy:
122 if (stat(xbt_binary_name, &stat_buf) == 0)
123 return xbt_binary_name;
125 // Not found, look in the PATH:
126 char* path = getenv("PATH");
129 XBT_DEBUG("Looking in the PATH: %s\n", path);
130 std::vector<std::string> path_list;
131 // TODO, on Windows, this is ";"
132 boost::split(path_list, path, boost::is_any_of(":"));
133 for (std::string const& path_item : path_list) {
134 std::string binary_name = simgrid::xbt::string_printf(
135 "%s/%s", path_item.c_str(), xbt_binary_name);
136 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
137 XBT_DEBUG("Looked in the PATH for the binary. %s %s",
138 found ? "Found" : "Not found",
139 binary_name.c_str());
148 //FIXME: This code could be greatly improved/simplifyied with
149 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
150 std::vector<std::string> resolveBacktrace(
151 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:
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]));
170 return std::move(result);
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 %zd 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: %zd, '%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");
200 xbt_die("Cannot fork addr2line to display the backtrace");
203 /* To read the output of addr2line */
204 char line_func[1024], line_pos[1024];
205 for (std::size_t i = 0; i < count; i++) {
206 XBT_DEBUG("Looking for symbol %zd, 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 %zd, addr %s", i, addrs[i].c_str());
211 strncpy(line_func, "???",3);
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 %zd, 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(
224 "%s at %s, %p", name.get(), line_pos, loc[i]
227 /* Damn. The symbol is in a dynamic library. Let's get wild */
234 /* let's look for the offset of this library in our addressing space */
235 char* maps_name = bprintf("/proc/%d/maps", (int) getpid());
236 FILE* maps = fopen(maps_name, "r");
238 long int addr = strtol(addrs[i].c_str(), &p, 16);
240 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)",
241 addrs[i].c_str(), addr);
243 XBT_DEBUG("addr=%s (as string) =%#lx (as number)",
244 addrs[i].c_str(), addr);
247 long int first, last;
249 if (fgets(maps_buff, 512, maps) == NULL)
252 maps_buff[strlen(maps_buff) - 1] = '\0';
253 XBT_DEBUG("map line: %s", maps_buff);
255 sscanf(maps_buff, "%lx", &first);
256 p = strchr(maps_buff, '-') + 1;
257 sscanf(p, "%lx", &last);
258 if (first < addr && addr < last) {
263 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
264 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
272 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
273 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
274 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
278 /* Ok, Found the offset of the maps line containing the searched symbol.
279 We now need to substract this from the address we got from backtrace.
282 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
283 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
285 /* Got it. We have our new address. Let's get the library path and we are set */
286 p = xbt_strdup(backtrace_syms[i]);
288 /* library path not displayed in the map file either... */
290 snprintf(line_func,3, "??");
292 p2 = strrchr(p, '(');
295 p2 = strrchr(p, ' ');
299 /* Here we go, fire an addr2line up */
300 char* subcmd = bprintf("%s -f -e %s %s", ADDR2LINE, p, addrs[i].c_str());
302 XBT_VERB("Fire a new command: '%s'", subcmd);
303 FILE* subpipe = popen(subcmd, "r");
305 xbt_die("Cannot fork addr2line to display the backtrace");
307 if (fgets(line_func, 1024, subpipe)) {
308 line_func[strlen(line_func) - 1] = '\0';
310 XBT_VERB("Cannot read result of subcommand %s", subcmd);
311 strncpy(line_func, "???",3);
313 if (fgets(line_pos, 1024, subpipe)) {
314 line_pos[strlen(line_pos) - 1] = '\0';
316 XBT_VERB("Cannot read result of subcommand %s", subcmd);
317 strncpy(line_pos, backtrace_syms[i],1024);
323 /* check whether the trick worked */
324 if (strcmp("??", line_func)) {
325 auto name = simgrid::xbt::demangle(line_func);
326 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
327 result.push_back(simgrid::xbt::string_printf(
328 "%s at %s, %p", name.get(), line_pos, loc[i]));
330 /* damn, nothing to do here. Let's print the raw address */
331 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
332 result.push_back(simgrid::xbt::string_printf(
333 "?? at %s", backtrace_syms[i]));
338 /* Mask the bottom of the stack */
339 if (!strncmp("main", line_func, strlen("main")) ||
340 !strncmp("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper"))
341 || !strncmp("smx_ctx_sysv_wrapper", line_func, strlen("smx_ctx_sysv_wrapper")))
345 free(backtrace_syms);
353 int xbt_libunwind_backtrace(void** bt, int size){
355 for(i=0; i < size; i++)
363 unw_getcontext (&uc);
364 unw_init_local (&c, &uc);
370 while(unw_step(&c) >= 0 && i < size){
371 unw_get_reg(&c, UNW_REG_IP, &ip);
372 bt[i] = (void*)(long)ip;