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) 2008-2015. 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. */
16 /* 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 */
17 #include <xbt/string.hpp>
19 #include "src/xbt/ex_interface.h"
22 #include "xbt/module.h" /* xbt_binary_name */
23 #include "src/xbt_modinter.h" /* backtrace initialization headers */
25 #define UNW_LOCAL_ONLY
26 #include <libunwind.h>
28 /* end of "useless" inclusions */
30 extern char **environ; /* the environment, as specified by the opengroup */
32 /* Module creation/destruction: nothing to do on linux */
33 void xbt_backtrace_preinit(void)
37 void xbt_backtrace_postexit(void)
47 static _Unwind_Reason_Code
48 backtrace_helper (struct _Unwind_Context *ctx, void *a)
50 struct trace_arg *arg = (struct trace_arg *) a;
52 /* We are first called with address in the __backtrace function.
56 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
58 /* Check whether we make any progress. */
59 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
60 return _URC_END_OF_STACK;
62 if (++arg->cnt == arg->size)
63 return _URC_END_OF_STACK;
64 return _URC_NO_REASON;
67 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
69 * See http://webloria.loria.fr/~quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
70 * for the motivation behind this function
73 int xbt_backtrace_no_malloc(void **array, int size) {
75 for(i=0; i < size; i++)
84 _Unwind_Backtrace(backtrace_helper, &arg);
86 /* _Unwind_Backtrace on IA-64 seems to put NULL address above
87 _start. Fix it up here. */
88 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
90 return arg.cnt != -1 ? arg.cnt : 0;
93 size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
95 std::size_t used = backtrace(loc, count);
97 std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
98 std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
99 std::fprintf(stderr, "Please go fix the memleaks\n");
108 //FIXME: This code could be greatly improved/simplifyied with
109 // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
110 std::vector<std::string> resolveBacktrace(
111 xbt_backtrace_location_t* loc, std::size_t count)
113 std::vector<std::string> result;
115 /* To search for the right executable path when not trivial */
116 struct stat stat_buf;
118 /* no binary name, nothing to do */
119 if (xbt_binary_name == NULL)
125 // Drop the first one:
128 char** backtrace_syms = backtrace_symbols(loc, count);
130 // Find the binary name:
131 std::string binary_name;
132 /* build the commandline */
133 if (stat(xbt_binary_name, &stat_buf)) {
134 /* Damn. binary not in current dir. We'll have to dig the PATH to find it */
135 for (std::size_t i = 0; environ[i]; i++) {
136 if (!strncmp("PATH=", environ[i], 5)) {
137 xbt_dynar_t path = xbt_str_split(environ[i] + 5, ":");
141 xbt_dynar_foreach(path, cpt, data) {
142 binary_name = simgrid::xbt::string_printf("%s/%s", data, xbt_binary_name);
143 if (!stat(binary_name.c_str(), &stat_buf)) {
145 XBT_DEBUG("Looked in the PATH for the binary. Found %s", binary_name.c_str());
149 xbt_dynar_free(&path);
150 if (stat(binary_name.c_str(), &stat_buf)) {
152 result = { simgrid::xbt::string_printf(
153 "(binary '%s' not found in the PATH)", xbt_binary_name) };
154 free(backtrace_syms);
161 binary_name = xbt_binary_name;
164 // Create the system command for add2line:
165 std::ostringstream stream;
166 stream << ADDR2LINE << " -f -e " << binary_name << ' ';
167 std::vector<std::string> addrs(count);
168 for (std::size_t i = 0; i < count; i++) {
169 /* retrieve this address */
170 XBT_DEBUG("Retrieving address number %zd from '%s'", i, backtrace_syms[i]);
172 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
173 char* p = strchr(buff, ']');
175 if (strcmp(buff, "(nil)"))
179 XBT_DEBUG("Set up a new address: %zd, '%s'", i, addrs[i].c_str());
180 /* Add it to the command line args */
181 stream << addrs[i] << ' ';
184 std::string cmd = stream.str();
186 /* size (in char) of pointers on this arch */
187 int addr_len = addrs[0].size();
189 XBT_VERB("Fire a first command: '%s'", cmd.c_str());
190 FILE* pipe = popen(cmd.c_str(), "r");
192 xbt_die("Cannot fork addr2line to display the backtrace");
195 /* To read the output of addr2line */
196 char line_func[1024], line_pos[1024];
197 for (std::size_t i = 0; i < count; i++) {
198 XBT_DEBUG("Looking for symbol %zd, addr = '%s'", i, addrs[i].c_str());
199 if (fgets(line_func, 1024, pipe)) {
200 line_func[strlen(line_func) - 1] = '\0';
202 XBT_VERB("Cannot run fgets to look for symbol %zd, addr %s", i, addrs[i].c_str());
203 strncpy(line_func, "???",3);
205 if (fgets(line_pos, 1024, pipe)) {
206 line_pos[strlen(line_pos) - 1] = '\0';
208 XBT_VERB("Cannot run fgets to look for symbol %zd, addr %s", i, addrs[i].c_str());
209 strncpy(line_pos, backtrace_syms[i],1024);
212 if (strcmp("??", line_func) != 0) {
213 XBT_DEBUG("Found static symbol %s() at %s", line_func, line_pos);
214 result.push_back(simgrid::xbt::string_printf(
215 "%s() at %s", line_func, line_pos
218 /* Damn. The symbol is in a dynamic library. Let's get wild */
225 /* let's look for the offset of this library in our addressing space */
226 char* maps_name = bprintf("/proc/%d/maps", (int) getpid());
227 FILE* maps = fopen(maps_name, "r");
229 long int addr = strtol(addrs[i].c_str(), &p, 16);
231 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)",
232 addrs[i].c_str(), addr);
234 XBT_DEBUG("addr=%s (as string) =%#lx (as number)",
235 addrs[i].c_str(), addr);
238 long int first, last;
240 if (fgets(maps_buff, 512, maps) == NULL)
243 maps_buff[strlen(maps_buff) - 1] = '\0';
244 XBT_DEBUG("map line: %s", maps_buff);
246 sscanf(maps_buff, "%lx", &first);
247 p = strchr(maps_buff, '-') + 1;
248 sscanf(p, "%lx", &last);
249 if (first < addr && addr < last) {
254 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
255 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
263 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
264 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
265 result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[i]));
269 /* Ok, Found the offset of the maps line containing the searched symbol.
270 We now need to substract this from the address we got from backtrace.
273 addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
274 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
276 /* Got it. We have our new address. Let's get the library path and we are set */
277 p = xbt_strdup(backtrace_syms[i]);
279 /* library path not displayed in the map file either... */
281 snprintf(line_func,3, "??");
283 p2 = strrchr(p, '(');
286 p2 = strrchr(p, ' ');
290 /* Here we go, fire an addr2line up */
291 char* subcmd = bprintf("%s -f -e %s %s", ADDR2LINE, p, addrs[i].c_str());
293 XBT_VERB("Fire a new command: '%s'", subcmd);
294 FILE* subpipe = popen(subcmd, "r");
296 xbt_die("Cannot fork addr2line to display the backtrace");
298 if (fgets(line_func, 1024, subpipe)) {
299 line_func[strlen(line_func) - 1] = '\0';
301 XBT_VERB("Cannot read result of subcommand %s", subcmd);
302 strncpy(line_func, "???",3);
304 if (fgets(line_pos, 1024, subpipe)) {
305 line_pos[strlen(line_pos) - 1] = '\0';
307 XBT_VERB("Cannot read result of subcommand %s", subcmd);
308 strncpy(line_pos, backtrace_syms[i],1024);
314 /* check whether the trick worked */
315 if (strcmp("??", line_func)) {
316 XBT_DEBUG("Found dynamic symbol %s() at %s", line_func, line_pos);
317 result.push_back(simgrid::xbt::string_printf(
318 "%s() at %s", line_func, line_pos));
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(
323 "?? at %s", backtrace_syms[i]));
328 /* Mask the bottom of the stack */
329 if (!strncmp("main", line_func, strlen("main")) ||
330 !strncmp("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper"))
331 || !strncmp("smx_ctx_sysv_wrapper", line_func, strlen("smx_ctx_sysv_wrapper")))
335 free(backtrace_syms);
343 int xbt_libunwind_backtrace(void** bt, int size){
345 for(i=0; i < size; i++)
353 unw_getcontext (&uc);
354 unw_init_local (&c, &uc);
360 while(unw_step(&c) >= 0 && i < size){
361 unw_get_reg(&c, UNW_REG_IP, &ip);
362 bt[i] = (void*)(long)ip;