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 backtrace_helper(_Unwind_Context* ctx, void* a)
43 trace_arg* arg = static_cast<trace_arg*>(a);
45 /* We are first called with address in the __backtrace function.
49 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
51 /* Check whether we make any progress. */
52 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
53 return _URC_END_OF_STACK;
55 if (++arg->cnt == arg->size)
56 return _URC_END_OF_STACK;
57 return _URC_NO_REASON;
60 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
62 * See http://people.irisa.fr/Martin.Quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
63 * for the motivation behind this function
66 int xbt_backtrace_no_malloc(void **array, int size) {
68 for(i=0; i < size; i++)
77 _Unwind_Backtrace(backtrace_helper, &arg);
79 /* _Unwind_Backtrace on IA-64 seems to put nullptr address above
80 _start. Fix it up here. */
81 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == nullptr)
83 return arg.cnt != -1 ? arg.cnt : 0;
86 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
88 std::size_t used = backtrace(loc, count);
90 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
91 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
92 std::fprintf(stderr, "Please go fix the memleaks\n");
101 /** Find the path of the binary file from the name found in argv */
102 static std::string get_binary_path()
104 struct stat stat_buf;
106 if (xbt_binary_name == nullptr)
109 // We found it, we are happy:
110 if (stat(xbt_binary_name, &stat_buf) == 0)
111 return xbt_binary_name;
113 // Not found, look in the PATH:
114 char* path = getenv("PATH");
117 XBT_DEBUG("Looking in the PATH: %s\n", path);
118 std::vector<std::string> path_list;
119 // TODO, on Windows, this is ";"
120 boost::split(path_list, path, boost::is_any_of(":"));
121 for (std::string const& path_item : path_list) {
122 std::string binary_name = simgrid::xbt::string_printf(
123 "%s/%s", path_item.c_str(), xbt_binary_name);
124 bool found = (stat(binary_name.c_str(), &stat_buf) == 0);
125 XBT_DEBUG("Looked in the PATH for the binary. %s %s",
126 found ? "Found" : "Not found",
127 binary_name.c_str());
136 //FIXME: This code could be greatly improved/simplifyied with
137 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
138 std::vector<std::string> resolveBacktrace(
139 xbt_backtrace_location_t const* loc, std::size_t count)
141 std::vector<std::string> result;
146 if (xbt_binary_name == nullptr)
147 XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
149 // Drop the first one:
152 char** backtrace_syms = backtrace_symbols(loc, count);
153 std::string binary_name = get_binary_path();
155 if (binary_name.empty()) {
156 for (std::size_t i = 0; i < count; i++)
157 result.push_back(simgrid::xbt::string_printf("%p", loc[i]));
161 // Create the system command for add2line:
162 std::ostringstream stream;
163 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
164 std::vector<std::string> addrs(count);
165 for (std::size_t i = 0; i < count; i++) {
166 /* retrieve this address */
167 XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
169 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
170 char* p = strchr(buff, ']');
172 if (strcmp(buff, "(nil)"))
176 XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
177 /* Add it to the command line args */
178 stream << addrs[i] << ' ';
180 std::string cmd = stream.str();
182 /* size (in char) of pointers on this arch */
183 int addr_len = addrs[0].size();
185 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
186 FILE* pipe = popen(cmd.c_str(), "r");
188 xbt_die("Cannot fork addr2line to display the backtrace");
191 /* To read the output of addr2line */
192 char line_func[1024];
194 for (std::size_t i = 0; i < count; i++) {
195 XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
196 if (fgets(line_func, 1024, pipe)) {
197 line_func[strlen(line_func) - 1] = '\0';
199 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
200 strncpy(line_func, "???",3);
202 if (fgets(line_pos, 1024, pipe)) {
203 line_pos[strlen(line_pos) - 1] = '\0';
205 XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
206 strncpy(line_pos, backtrace_syms[i],1024);
209 if (strcmp("??", line_func) != 0) {
210 auto name = simgrid::xbt::demangle(line_func);
211 XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
212 result.push_back(simgrid::xbt::string_printf(
213 "%s at %s, %p", name.get(), line_pos, loc[i]
216 /* Damn. The symbol is in a dynamic library. Let's get wild */
219 unsigned long int offset = 0;
223 /* let's look for the offset of this library in our addressing space */
224 std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "maps";
225 FILE* maps = fopen(maps_name.c_str(), "r");
227 unsigned long int addr = strtoul(addrs[i].c_str(), &p, 16);
229 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
231 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
234 unsigned long int first;
235 unsigned long int last;
237 if (fgets(maps_buff, 512, maps) == nullptr)
240 maps_buff[strlen(maps_buff) - 1] = '\0';
241 XBT_DEBUG("map line: %s", maps_buff);
243 sscanf(maps_buff, "%lx", &first);
244 p = strchr(maps_buff, '-') + 1;
245 sscanf(p, "%lx", &last);
246 if (first < addr && addr < last) {
251 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
252 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
259 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
260 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
261 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
265 /* Ok, Found the offset of the maps line containing the searched symbol.
266 We now need to substract this from the address we got from backtrace.
269 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
270 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
272 /* Got it. We have our new address. Let's get the library path and we are set */
273 p = xbt_strdup(backtrace_syms[i]);
275 /* library path not displayed in the map file either... */
277 snprintf(line_func,3, "??");
279 char* p2 = strrchr(p, '(');
282 p2 = strrchr(p, ' ');
286 /* Here we go, fire an addr2line up */
287 std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
289 XBT_VERB("Fire a new command: '%s'", subcmd.c_str());
290 FILE* subpipe = popen(subcmd.c_str(), "r");
292 xbt_die("Cannot fork addr2line to display the backtrace");
294 if (fgets(line_func, 1024, subpipe)) {
295 line_func[strlen(line_func) - 1] = '\0';
297 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
298 strncpy(line_func, "???",3);
300 if (fgets(line_pos, 1024, subpipe)) {
301 line_pos[strlen(line_pos) - 1] = '\0';
303 XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
304 strncpy(line_pos, backtrace_syms[i],1024);
309 /* check whether the trick worked */
310 if (strcmp("??", line_func)) {
311 auto name = simgrid::xbt::demangle(line_func);
312 XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
313 result.push_back(simgrid::xbt::string_printf(
314 "%s at %s, %p", name.get(), line_pos, loc[i]));
316 /* damn, nothing to do here. Let's print the raw address */
317 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
318 result.push_back(simgrid::xbt::string_printf(
319 "?? at %s", backtrace_syms[i]));
324 /* Mask the bottom of the stack */
325 if (not strncmp("main", line_func, strlen("main")) ||
326 not strncmp("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper")) ||
327 not strncmp("smx_ctx_sysv_wrapper", line_func, strlen("smx_ctx_sysv_wrapper")))
331 free(backtrace_syms);
339 int xbt_libunwind_backtrace(void** bt, int size){
340 for (int i = 0; i < size; i++)
346 unw_getcontext (&uc);
347 unw_init_local (&c, &uc);
352 for (i = 0; unw_step(&c) >= 0 && i < size; i++) {
354 unw_get_reg(&c, UNW_REG_IP, &ip);
355 bt[i] = (void*)(long)ip;