1 /* backtrace_linux - backtrace displaying on linux platform */
2 /* This file is included by ex.c on need (have execinfo.h, popen & addrline)*/
4 /* Copyright (c) 2008, 2009, 2010. 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. */
10 /* This file is to be included in ex.c, so the following headers are not mandatory, but it's to make sure that eclipse see them too */
13 #include "xbt/module.h" /* xbt_binary_name */
14 #include "xbt_modinter.h" /* backtrace initialization headers */
15 #include <libunwind.h>
16 /* end of "useless" inclusions */
18 extern char **environ; /* the environment, as specified by the opengroup */
20 /* Module creation/destruction: nothing to do on linux */
21 void xbt_backtrace_preinit(void)
25 void xbt_backtrace_postexit(void)
35 static _Unwind_Reason_Code
36 backtrace_helper (struct _Unwind_Context *ctx, void *a)
38 struct trace_arg *arg = a;
40 /* We are first called with address in the __backtrace function.
44 arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
46 /* Check whether we make any progress. */
47 if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
48 return _URC_END_OF_STACK;
50 if (++arg->cnt == arg->size)
51 return _URC_END_OF_STACK;
52 return _URC_NO_REASON;
55 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
57 * See http://webloria.loria.fr/~quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
58 * for the motivation behind this function
61 int xbt_backtrace_no_malloc(void **array, int size) {
64 for(i=0; i < size; i++)
67 struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
70 _Unwind_Backtrace(backtrace_helper, &arg);
72 /* _Unwind_Backtrace on IA-64 seems to put NULL address above
73 _start. Fix it up here. */
74 if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
76 return arg.cnt != -1 ? arg.cnt : 0;
79 void xbt_backtrace_current(xbt_ex_t * e)
81 e->used = backtrace((void **) e->bt, XBT_BACKTRACE_SIZE);
83 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:");
84 fprintf(stderr, "%s(%d) [%s:%d] %s",
85 e->procname, e->pid, e->file, e->line, e->msg);
86 fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory. Please go fix the memleaks\n");
92 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
96 /* to get the backtrace from the libc */
97 char **backtrace_syms;
99 /* To build the commandline of addr2line */
102 /* to extract the addresses from the backtrace */
106 /* To read the output of addr2line */
108 char line_func[1024], line_pos[1024];
110 /* size (in char) of pointers on this arch */
113 /* To search for the right executable path when not trivial */
114 struct stat stat_buf;
115 char *binary_name = NULL;
117 xbt_assert(e, "Backtrace not setup yet, cannot set it up for display");
119 e->bt_strings = NULL;
121 if (xbt_binary_name == NULL) /* no binary name, nothing to do */
127 /* ignore first one, which is xbt_backtrace_current() */
129 memmove(e->bt, e->bt + 1, (sizeof *e->bt) * e->used);
131 backtrace_syms = backtrace_symbols(e->bt, e->used);
133 /* build the commandline */
134 if (stat(xbt_binary_name, &stat_buf)) {
135 /* Damn. binary not in current dir. We'll have to dig the PATH to find it */
136 for (i = 0; environ[i]; i++) {
137 if (!strncmp("PATH=", environ[i], 5)) {
138 xbt_dynar_t path = xbt_str_split(environ[i] + 5, ":");
142 xbt_dynar_foreach(path, cpt, data) {
144 binary_name = bprintf("%s/%s", data, xbt_binary_name);
145 if (!stat(binary_name, &stat_buf)) {
147 XBT_DEBUG("Looked in the PATH for the binary. Found %s",
152 xbt_dynar_free(&path);
153 if (stat(binary_name, &stat_buf)) {
156 e->bt_strings = xbt_new(char *, 1);
159 bprintf("(binary '%s' not found in the PATH)", xbt_binary_name);
160 free(backtrace_syms);
167 binary_name = xbt_strdup(xbt_binary_name);
171 strlen(ADDR2LINE) + 25 + strlen(binary_name) + 32 * e->used);
173 curr += sprintf(curr, "%s -f -e %s ", ADDR2LINE, binary_name);
176 addrs = xbt_new(char *, e->used);
177 for (i = 0; i < e->used; i++) {
179 /* retrieve this address */
180 XBT_DEBUG("Retrieving address number %d from '%s'", i, backtrace_syms[i]);
181 snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
182 p = strchr(buff, ']');
184 if (strcmp(buff, "(nil)"))
185 addrs[i] = xbt_strdup(buff);
187 addrs[i] = xbt_strdup("0x0");
188 XBT_DEBUG("Set up a new address: %d, '%s'(%p)", i, addrs[i], addrs[i]);
190 /* Add it to the command line args */
191 curr += sprintf(curr, "%s ", addrs[i]);
193 addr_len = strlen(addrs[0]);
195 /* parse the output and build a new backtrace */
196 e->bt_strings = xbt_new(char *, e->used);
198 XBT_VERB("Fire a first command: '%s'", cmd);
199 pipe = popen(cmd, "r");
201 xbt_die("Cannot fork addr2line to display the backtrace");
204 for (i = 0; i < e->used; i++) {
205 XBT_DEBUG("Looking for symbol %d, addr = '%s'", i, addrs[i]);
206 if (fgets(line_func, 1024, pipe)) {
207 line_func[strlen(line_func) - 1] = '\0';
209 XBT_VERB("Cannot run fgets to look for symbol %d, addr %s", i, addrs[i]);
210 strcpy(line_func, "???");
212 if (fgets(line_pos, 1024, pipe)) {
213 line_pos[strlen(line_pos) - 1] = '\0';
215 XBT_VERB("Cannot run fgets to look for symbol %d, addr %s", i, addrs[i]);
216 strcpy(line_pos, backtrace_syms[i]);
219 if (strcmp("??", line_func) != 0) {
220 XBT_DEBUG("Found static symbol %s() at %s", line_func, line_pos);
222 bprintf("** In %s() at %s", line_func, line_pos);
224 /* Damn. The symbol is in a dynamic library. Let's get wild */
229 long int addr, offset = 0;
236 /* let's look for the offset of this library in our addressing space */
237 maps_name = bprintf("/proc/%d/maps", (int) getpid());
238 maps = fopen(maps_name, "r");
240 addr = strtol(addrs[i], &p, 16);
242 XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)",
245 XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i], addr);
248 long int first, last;
250 if (fgets(maps_buff, 512, maps) == NULL)
253 maps_buff[strlen(maps_buff) - 1] = '\0';
254 XBT_DEBUG("map line: %s", maps_buff);
256 sscanf(maps_buff, "%lx", &first);
257 p = strchr(maps_buff, '-') + 1;
258 sscanf(p, "%lx", &last);
259 if (first < addr && addr < last) {
264 XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
266 ("Symbol found, map lines not further displayed (even if looking for next ones)");
275 ("Problem while reading the maps file. Following backtrace will be mangled.");
276 XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
277 e->bt_strings[i] = bprintf("** In ?? (%s)", backtrace_syms[i]);
281 /* Ok, Found the offset of the maps line containing the searched symbol.
282 We now need to substract this from the address we got from backtrace.
285 addrs[i] = bprintf("0x%0*lx", addr_len - 2, addr - offset);
286 XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i]);
288 /* Got it. We have our new address. Let's get the library path and we
290 p = xbt_strdup(backtrace_syms[i]);
292 /* library path not displayed in the map file either... */
294 sprintf(line_func, "??");
296 p2 = strrchr(p, '(');
299 p2 = strrchr(p, ' ');
303 /* Here we go, fire an addr2line up */
304 subcmd = bprintf("%s -f -e %s %s", ADDR2LINE, p, addrs[i]);
306 XBT_VERB("Fire a new command: '%s'", subcmd);
307 subpipe = popen(subcmd, "r");
309 xbt_die("Cannot fork addr2line to display the backtrace");
311 if (fgets(line_func, 1024, subpipe)) {
312 line_func[strlen(line_func) - 1] = '\0';
314 XBT_VERB("Cannot read result of subcommand %s", subcmd);
315 strcpy(line_func, "???");
317 if (fgets(line_pos, 1024, subpipe)) {
318 line_pos[strlen(line_pos) - 1] = '\0';
320 XBT_VERB("Cannot read result of subcommand %s", subcmd);
321 strcpy(line_pos, backtrace_syms[i]);
327 /* check whether the trick worked */
328 if (strcmp("??", line_func)) {
329 XBT_DEBUG("Found dynamic symbol %s() at %s", line_func, line_pos);
331 bprintf("** In %s() at %s", line_func, line_pos);
333 /* damn, nothing to do here. Let's print the raw address */
334 XBT_DEBUG("Dynamic symbol not found. Raw address = %s",
336 e->bt_strings[i] = bprintf("** In ?? at %s", backtrace_syms[i]);
342 /* Mask the bottom of the stack */
343 if (!strncmp("main", line_func, strlen("main")) ||
344 !strncmp("xbt_thread_context_wrapper", line_func,
345 strlen("xbt_thread_context_wrapper"))
346 || !strncmp("smx_ctx_sysv_wrapper", line_func,
347 strlen("smx_ctx_sysv_wrapper"))) {
350 for (j = i + 1; j < e->used; j++)
355 ("xbt_thread_context_wrapper", line_func,
356 strlen("xbt_thread_context_wrapper"))) {
357 free(e->bt_strings[i]);
358 e->bt_strings[i] = xbt_strdup("** (in a separate thread)");
366 free(backtrace_syms);
370 int xbt_libunwind_backtrace(void* bt[XBT_BACKTRACE_SIZE], int size){
373 for(i=0; i < size; i++)
381 unw_getcontext (&uc);
382 unw_init_local (&c, &uc);
388 while(unw_step(&c) >= 0 && i < size){
390 unw_get_reg(&c, UNW_REG_IP, &ip);
391 bt[i] = (void*)(long)ip;