X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/68d9296755037890af2700e6f7b39222f8fd523b..3719170cd3de26a8fc027b9a6bb539a195b9e08c:/src/xbt/backtrace_linux.c

diff --git a/src/xbt/backtrace_linux.c b/src/xbt/backtrace_linux.c
index e4eda28d87..04a26c714f 100644
--- a/src/xbt/backtrace_linux.c
+++ b/src/xbt/backtrace_linux.c
@@ -25,6 +25,56 @@ void xbt_backtrace_postexit(void)
 {
 }
 
+#include <unwind.h>
+struct trace_arg {
+  void **array;
+  int cnt, size;
+};
+
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+  struct trace_arg *arg = a;
+
+  /* We are first called with address in the __backtrace function.
+     Skip it.  */
+  if (arg->cnt != -1)
+    {
+      arg->array[arg->cnt] = (void *) _Unwind_GetIP(ctx);
+
+      /* Check whether we make any progress.  */
+      if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt])
+        return _URC_END_OF_STACK;
+    }
+  if (++arg->cnt == arg->size)
+    return _URC_END_OF_STACK;
+  return _URC_NO_REASON;
+}
+
+/** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc
+ *
+ * See http://webloria.loria.fr/~quinson/blog/2012/0208/system_programming_fun_in_SimGrid/
+ * for the motivation behind this function
+ * */
+
+int xbt_backtrace_no_malloc(void **array, int size) {
+
+  int i = 0;
+  for(i=0; i < size; i++)
+    array[i] = NULL;
+
+  struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+
+  if (size >= 1)
+    _Unwind_Backtrace(backtrace_helper, &arg);
+
+  /* _Unwind_Backtrace on IA-64 seems to put NULL address above
+     _start.  Fix it up here.  */
+  if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+    --arg.cnt;
+  return arg.cnt != -1 ? arg.cnt : 0;
+}
+
 void xbt_backtrace_current(xbt_ex_t * e)
 {
   e->used = backtrace((void **) e->bt, XBT_BACKTRACE_SIZE);
@@ -37,7 +87,7 @@ void xbt_backtrace_current(xbt_ex_t * e)
 }
 
 
-void xbt_ex_setup_backtrace(xbt_ex_t * e)
+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
 {
   int i;
 
@@ -49,7 +99,7 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
 
   /* to extract the addresses from the backtrace */
   char **addrs;
-  char buff[256], *p;
+  char buff[256];
 
   /* To read the output of addr2line */
   FILE *pipe;
@@ -62,29 +112,25 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
   struct stat stat_buf;
   char *binary_name = NULL;
 
-  xbt_assert(e
-              && e->used,
-              "Backtrace not setup yet, cannot set it up for display");
+  xbt_assert(e, "Backtrace not setup yet, cannot set it up for display");
+
+  e->bt_strings = NULL;
+
+  if (xbt_binary_name == NULL) /* no binary name, nothing to do */
+    return;
 
-  if (!xbt_binary_name) /* no binary name, nothing to do */
+  if (e->used <= 1)
     return;
 
-  backtrace_syms = backtrace_symbols(e->bt, e->used);
-  /* ignore first one, which is this xbt_backtrace_current() */
+  /* ignore first one, which is xbt_backtrace_current() */
   e->used--;
-  memmove(backtrace_syms, backtrace_syms + 1, sizeof(char *) * e->used);
-
-  e->bt_strings = NULL;
+  memmove(e->bt, e->bt + 1, (sizeof *e->bt) * e->used);
 
-  /* Some arches only have stubs of backtrace, no implementation (hppa comes to mind) */
-  if (!e->used)
-    return;
+  backtrace_syms = backtrace_symbols(e->bt, e->used);
 
   /* build the commandline */
   if (stat(xbt_binary_name, &stat_buf)) {
     /* Damn. binary not in current dir. We'll have to dig the PATH to find it */
-    int i;
-
     for (i = 0; environ[i]; i++) {
       if (!strncmp("PATH=", environ[i], 5)) {
         xbt_dynar_t path = xbt_str_split(environ[i] + 5, ":");
@@ -92,8 +138,7 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
         char *data;
 
         xbt_dynar_foreach(path, cpt, data) {
-          if (binary_name)
-            free(binary_name);
+          free(binary_name);
           binary_name = bprintf("%s/%s", data, xbt_binary_name);
           if (!stat(binary_name, &stat_buf)) {
             /* Found. */
@@ -109,7 +154,7 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
           e->bt_strings = xbt_new(char *, 1);
 
           e->bt_strings[0] =
-              bprintf("(binary '%s' not found the path)", xbt_binary_name);
+              bprintf("(binary '%s' not found in the PATH)", xbt_binary_name);
           free(backtrace_syms);
           return;
         }
@@ -128,6 +173,7 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
 
   addrs = xbt_new(char *, e->used);
   for (i = 0; i < e->used; i++) {
+    char *p;
     /* retrieve this address */
     XBT_DEBUG("Retrieving address number %d from '%s'", i, backtrace_syms[i]);
     snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
@@ -150,27 +196,25 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
   XBT_VERB("Fire a first command: '%s'", cmd);
   pipe = popen(cmd, "r");
   if (!pipe) {
-    XBT_CRITICAL("Cannot fork addr2line to display the backtrace");
-    abort();
+    xbt_die("Cannot fork addr2line to display the backtrace");
   }
 
   for (i = 0; i < e->used; i++) {
-    char *fgets_res;
     XBT_DEBUG("Looking for symbol %d, addr = '%s'", i, addrs[i]);
-    fgets_res = fgets(line_func, 1024, pipe);
-    if (fgets_res == NULL)
-      THROWF(system_error, 0,
-             "Cannot run fgets to look for symbol %d, addr %s", i,
-             addrs[i]);
-    line_func[strlen(line_func) - 1] = '\0';
-    fgets_res = fgets(line_pos, 1024, pipe);
-    if (fgets_res == NULL)
-      THROWF(system_error, 0,
-             "Cannot run fgets to look for symbol %d, addr %s", i,
-             addrs[i]);
-    line_pos[strlen(line_pos) - 1] = '\0';
-
-    if (strcmp("??", line_func)) {
+    if (fgets(line_func, 1024, pipe)) {
+      line_func[strlen(line_func) - 1] = '\0';
+    } else {
+      XBT_VERB("Cannot run fgets to look for symbol %d, addr %s", i, addrs[i]);
+      strcpy(line_func, "???");
+    }
+    if (fgets(line_pos, 1024, pipe)) {
+      line_pos[strlen(line_pos) - 1] = '\0';
+    } else {
+      XBT_VERB("Cannot run fgets to look for symbol %d, addr %s", i, addrs[i]);
+      strcpy(line_pos, backtrace_syms[i]);
+    }
+
+    if (strcmp("??", line_func) != 0) {
       XBT_DEBUG("Found static symbol %s() at %s", line_func, line_pos);
       e->bt_strings[i] =
           bprintf("**   In %s() at %s", line_func, line_pos);
@@ -260,19 +304,20 @@ void xbt_ex_setup_backtrace(xbt_ex_t * e)
         XBT_VERB("Fire a new command: '%s'", subcmd);
         subpipe = popen(subcmd, "r");
         if (!subpipe) {
-          XBT_CRITICAL("Cannot fork addr2line to display the backtrace");
-          abort();
+          xbt_die("Cannot fork addr2line to display the backtrace");
+        }
+        if (fgets(line_func, 1024, subpipe)) {
+          line_func[strlen(line_func) - 1] = '\0';
+        } else {
+          XBT_VERB("Cannot read result of subcommand %s", subcmd);
+          strcpy(line_func, "???");
+        }
+        if (fgets(line_pos, 1024, subpipe)) {
+          line_pos[strlen(line_pos) - 1] = '\0';
+        } else {
+          XBT_VERB("Cannot read result of subcommand %s", subcmd);
+          strcpy(line_pos, backtrace_syms[i]);
         }
-        fgets_res = fgets(line_func, 1024, subpipe);
-        if (fgets_res == NULL)
-          THROWF(system_error, 0, "Cannot read result of subcommand %s",
-                 subcmd);
-        line_func[strlen(line_func) - 1] = '\0';
-        fgets_res = fgets(line_pos, 1024, subpipe);
-        if (fgets_res == NULL)
-          THROWF(system_error, 0, "Cannot read result of subcommand %s",
-                 subcmd);
-        line_pos[strlen(line_pos) - 1] = '\0';
         pclose(subpipe);
         free(subcmd);
       }