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. */
14 /* 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 */
18 #include "xbt/module.h" /* xbt_binary_name */
19 #include "src/xbt_modinter.h" /* backtrace initialization headers */
21 #define UNW_LOCAL_ONLY
22 #include <libunwind.h>
24 /* end of "useless" inclusions */
26 extern char **environ; /* the environment, as specified by the opengroup */
28 /* Module creation/destruction: nothing to do on linux */
29 void xbt_backtrace_preinit(void)
33 void xbt_backtrace_postexit(void)
43 static _Unwind_Reason_Code
44 backtrace_helper (struct _Unwind_Context *ctx, void *a)
46 struct trace_arg *arg = (struct trace_arg *) a;
48 /* We are first called with address in the __backtrace function.
52 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
54 /* Check whether we make any progress. */
55 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
56 return _URC_END_OF_STACK;
58 if (++arg->cnt == arg->size)
59 return _URC_END_OF_STACK;
60 return _URC_NO_REASON;
63 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
65 * See http://webloria.loria.fr/~quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
66 * for the motivation behind this function
69 int xbt_backtrace_no_malloc(void **array, int size) {
71 for(i=0; i < size; i++)
80 _Unwind_Backtrace(backtrace_helper, &arg);
82 /* _Unwind_Backtrace on IA-64 seems to put NULL address above
83 _start. Fix it up here. */
84 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
86 return arg.cnt != -1 ? arg.cnt : 0;
89 void xbt_backtrace_current(xbt_ex_t * e)
91 void* bt[XBT_BACKTRACE_SIZE];
92 std::size_t used = backtrace((void **) bt, XBT_BACKTRACE_SIZE);
93 e->bt.assign(bt, bt + used);
95 fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted. Here is a crude dump of the exception that I was trying to build:");
96 fprintf(stderr, "%s(%d) [%s:%d] %s",
97 e->procname.c_str(), e->pid, e->file, e->line, e->what());
98 fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory. Please go fix the memleaks\n");
103 void xbt_ex_setup_backtrace(xbt_ex_t * e) //FIXME: This code could be greatly improved/simplifyied with http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
105 /* to get the backtrace from the libc */
106 char **backtrace_syms;
108 /* To build the commandline of addr2line */
111 /* to extract the addresses from the backtrace */
115 /* To read the output of addr2line */
117 char line_func[1024], line_pos[1024];
119 /* size (in char) of pointers on this arch */
122 /* To search for the right executable path when not trivial */
123 struct stat stat_buf;
124 char *binary_name = NULL;
126 xbt_assert(e, "Backtrace not setup yet, cannot set it up for display");
128 e->bt_strings.clear();
130 if (xbt_binary_name == NULL) /* no binary name, nothing to do */
136 /* ignore first one, which is xbt_backtrace_current() */
137 e->bt.erase(e->bt.begin());
139 backtrace_syms = backtrace_symbols(e->bt.data(), e->bt.size());
141 /* build the commandline */
142 if (stat(xbt_binary_name, &stat_buf)) {
143 /* Damn. binary not in current dir. We'll have to dig the PATH to find it */
144 for (std::size_t i = 0; environ[i]; i++) {
145 if (!strncmp("PATH=", environ[i], 5)) {
146 xbt_dynar_t path = xbt_str_split(environ[i] + 5, ":");
150 xbt_dynar_foreach(path, cpt, data) {
152 binary_name = bprintf("%s/%s", data, xbt_binary_name);
153 if (!stat(binary_name, &stat_buf)) {
155 XBT_DEBUG("Looked in the PATH for the binary. Found %s", binary_name);
159 xbt_dynar_free(&path);
160 if (stat(binary_name, &stat_buf)) {
162 char* str = bprintf("(binary '%s' not found in the PATH)", xbt_binary_name);
163 e->bt_strings = { str };
165 free(backtrace_syms);
172 binary_name = xbt_strdup(xbt_binary_name);
174 int strsize = strlen(ADDR2LINE) + 25 + strlen(binary_name) + 32 * e->bt_strings.size();
175 cmd = curr = xbt_new(char, strsize);
177 curr += snprintf(curr,strsize, "%s -f -e %s ", ADDR2LINE, binary_name);
180 addrs = xbt_new(char *, e->bt.size());
181 for (std::size_t i = 0; i < e->bt.size(); i++) {
183 /* retrieve this address */
184 XBT_DEBUG("Retrieving address number %zd from '%s'", i, backtrace_syms[i]);
185 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
186 p = strchr(buff, ']');
188 if (strcmp(buff, "(nil)"))
189 addrs[i] = xbt_strdup(buff);
191 addrs[i] = xbt_strdup("0x0");
192 XBT_DEBUG("Set up a new address: %zd, '%s'(%p)", i, addrs[i], addrs[i]);
194 /* Add it to the command line args */
195 curr += snprintf(curr,strsize, "%s ", addrs[i]);
197 addr_len = strlen(addrs[0]);
199 /* parse the output and build a new backtrace */
200 e->bt_strings.resize(e->bt.size());
202 XBT_VERB("Fire a first command: '%s'", cmd);
203 pipe = popen(cmd, "r");
205 xbt_die("Cannot fork addr2line to display the backtrace");
208 for (std::size_t i = 0; i < e->bt.size(); i++) {
209 XBT_DEBUG("Looking for symbol %zd, addr = '%s'", i, addrs[i]);
210 if (fgets(line_func, 1024, pipe)) {
211 line_func[strlen(line_func) - 1] = '\0';
213 XBT_VERB("Cannot run fgets to look for symbol %zd, addr %s", i, addrs[i]);
214 strncpy(line_func, "???",3);
216 if (fgets(line_pos, 1024, pipe)) {
217 line_pos[strlen(line_pos) - 1] = '\0';
219 XBT_VERB("Cannot run fgets to look for symbol %zd, addr %s", i, addrs[i]);
220 strncpy(line_pos, backtrace_syms[i],1024);
223 if (strcmp("??", line_func) != 0) {
224 XBT_DEBUG("Found static symbol %s() at %s", line_func, line_pos);
225 char* s = bprintf("** In %s() at %s", line_func, line_pos);
226 e->bt_strings[i] = s;
229 /* Damn. The symbol is in a dynamic library. Let's get wild */
234 long int addr, offset = 0;
241 /* let's look for the offset of this library in our addressing space */
242 maps_name = bprintf("/proc/%d/maps", (int) getpid());
243 maps = fopen(maps_name, "r");
245 addr = strtol(addrs[i], &p, 16);
247 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i], addr);
249 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i], addr);
252 long int first, last;
254 if (fgets(maps_buff, 512, maps) == NULL)
257 maps_buff[strlen(maps_buff) - 1] = '\0';
258 XBT_DEBUG("map line: %s", maps_buff);
260 sscanf(maps_buff, "%lx", &first);
261 p = strchr(maps_buff, '-') + 1;
262 sscanf(p, "%lx", &last);
263 if (first < addr && addr < last) {
268 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
269 XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
277 XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
278 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
279 char* s = bprintf("** In ?? (%s)", backtrace_syms[i]);
280 e->bt_strings[i] = s;
285 /* Ok, Found the offset of the maps line containing the searched symbol.
286 We now need to substract this from the address we got from backtrace.
289 addrs[i] = bprintf("0x%0*lx", addr_len - 2, addr - offset);
290 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i]);
292 /* Got it. We have our new address. Let's get the library path and we are set */
293 p = xbt_strdup(backtrace_syms[i]);
295 /* library path not displayed in the map file either... */
297 snprintf(line_func,3, "??");
299 p2 = strrchr(p, '(');
302 p2 = strrchr(p, ' ');
306 /* Here we go, fire an addr2line up */
307 subcmd = bprintf("%s -f -e %s %s", ADDR2LINE, p, addrs[i]);
309 XBT_VERB("Fire a new command: '%s'", subcmd);
310 subpipe = popen(subcmd, "r");
312 xbt_die("Cannot fork addr2line to display the backtrace");
314 if (fgets(line_func, 1024, subpipe)) {
315 line_func[strlen(line_func) - 1] = '\0';
317 XBT_VERB("Cannot read result of subcommand %s", subcmd);
318 strncpy(line_func, "???",3);
320 if (fgets(line_pos, 1024, subpipe)) {
321 line_pos[strlen(line_pos) - 1] = '\0';
323 XBT_VERB("Cannot read result of subcommand %s", subcmd);
324 strncpy(line_pos, backtrace_syms[i],1024);
330 /* check whether the trick worked */
331 if (strcmp("??", line_func)) {
332 XBT_DEBUG("Found dynamic symbol %s() at %s", line_func, line_pos);
333 char* s = bprintf("** In %s() at %s", line_func, line_pos);
334 e->bt_strings[i] = s;
337 /* damn, nothing to do here. Let's print the raw address */
338 XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
339 char* s = bprintf("** In ?? at %s", backtrace_syms[i]);
340 e->bt_strings[i] = s;
346 /* Mask the bottom of the stack */
347 if (!strncmp("main", line_func, strlen("main")) ||
348 !strncmp("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper"))
349 || !strncmp("smx_ctx_sysv_wrapper", line_func, strlen("smx_ctx_sysv_wrapper"))) {
351 for (std::size_t j = i + 1; j < e->bt.size(); j++)
355 ("xbt_thread_context_wrapper", line_func, strlen("xbt_thread_context_wrapper"))) {
356 e->bt_strings.push_back("** (in a separate thread)");
358 e->bt_strings.push_back("");
365 free(backtrace_syms);
370 int xbt_libunwind_backtrace(void* bt[XBT_BACKTRACE_SIZE], int size){
372 for(i=0; i < size; i++)
380 unw_getcontext (&uc);
381 unw_init_local (&c, &uc);
387 while(unw_step(&c) >= 0 && i < size){
388 unw_get_reg(&c, UNW_REG_IP, &ip);
389 bt[i] = (void*)(long)ip;