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Implementation of the back trace functions for Win32 on the x86 architecture
[simgrid.git] / src / xbt / ex.c
index 4c4c6be..c8d593b 100644 (file)
-/*
-**  OSSP ex - Exception Handling (modified to fit into SimGrid)
-**  Copyright (c) 2005 Martin Quinson
-**  Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com>
-**  Copyright (c) 2002-2004 The OSSP Project <http://www.ossp.org/>
-**  Copyright (c) 2002-2004 Cable & Wireless <http://www.cw.com/>
-**
-**  This file is part of OSSP ex, an exception handling library
-**  which can be found at http://www.ossp.org/pkg/lib/ex/.
-**
-**  Permission to use, copy, modify, and distribute this software for
-**  any purpose with or without fee is hereby granted, provided that
-**  the above copyright notice and this permission notice appear in all
-**  copies.
-**
-**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
-**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
-**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
-**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
-**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-**  SUCH DAMAGE.
-**
-**  ex.c: exception handling (compiler part)
-*/
+/* $Id$ */
+
+/* ex - Exception Handling (modified to fit into SimGrid from OSSP version) */
+
+/*  Copyright (c) 2005, 2006, 2007 Martin Quinson                           */
+/*  Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com>       */
+/*  Copyright (c) 2002-2004 The OSSP Project <http://www.ossp.org/>         */
+/*  Copyright (c) 2002-2004 Cable & Wireless <http://www.cw.com/>           */
+/*  All rights reserved.                                                    */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "portable.h" /* execinfo when available */
 #include "xbt/ex.h"
+#include "xbt/str.h"
+#include "xbt/module.h" /* xbt_binary_name */
+#include "xbt/synchro.h" /* xbt_thread_self */
 
 #include "gras/Virtu/virtu_interface.h" /* gras_os_myname */
+#include "xbt/ex_interface.h"
+
+#if (defined(WIN32) && defined(_M_IX86))
+#include <dbghelp.h>
+#endif
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_ex,xbt,"Exception mecanism");
+
+#if (defined(WIN32) && defined(_M_IX86))
+
+/* 
+ * Win32 (x86) implementation backtrace, backtrace_symbols, backtrace_symbols_fd
+ * : support for application self-debugging.
+ */
+
+/* Pointer function to SymInitialize() */
+typedef BOOL (WINAPI *xbt_pfn_sym_initialize_t)(HANDLE, PSTR , BOOL);
+
+/* Pointer function to SymCleanup() */
+typedef BOOL (WINAPI *xbt_pfn_sym_cleanup_t)(HANDLE hProcess);
+
+/* Pointer function to SymFunctionTableAccess() */
+typedef PVOID (WINAPI *xbt_pfn_sym_function_table_access_t)(HANDLE, DWORD);
+
+/* Pointer function to SymGetLineFromAddr() */
+typedef BOOL (WINAPI *xbt_pfn_sym_get_line_from_addr_t)(HANDLE, DWORD, PDWORD , PIMAGEHLP_LINE);
+
+/* Pointer function to SymGetModuleBase() */
+typedef DWORD (WINAPI *xbt_pfn_sym_get_module_base_t)(HANDLE,DWORD);
+
+/* Pointer function to SymGetOptions() */
+typedef DWORD (WINAPI *xbt_pfn_sym_get_options_t)(VOID);
+
+/* Pointer function to SymGetSymFromAddr() */
+typedef BOOL (WINAPI *xbt_pfn_sym_get_sym_from_addr_t)(HANDLE, DWORD, PDWORD , OUT PIMAGEHLP_SYMBOL);
+
+/* Pointer function to SymSetOptions() */
+typedef DWORD (WINAPI *xbt_pfn_sym_set_options_t)(DWORD);
+
+/* Pointer function to StackWalk() */
+typedef BOOL (WINAPI *xbt_pfn_stack_walk_t)(DWORD, HANDLE, HANDLE ,LPSTACKFRAME, PVOID,PREAD_PROCESS_MEMORY_ROUTINE, PFUNCTION_TABLE_ACCESS_ROUTINE, PGET_MODULE_BASE_ROUTINE, PTRANSLATE_ADDRESS_ROUTINE);
+
+/* This structure representes the debug_help library used interface */
+typedef struct s_xbt_debug_help
+{
+       HINSTANCE instance;
+       HANDLE process_handle;                                                                                  
+       xbt_pfn_sym_initialize_t sym_initialize;
+       xbt_pfn_sym_cleanup_t sym_cleanup;
+       xbt_pfn_sym_function_table_access_t sym_function_table_access;
+       xbt_pfn_sym_get_line_from_addr_t sym_get_line_from_addr;
+       xbt_pfn_sym_get_module_base_t sym_get_module_base;
+       xbt_pfn_sym_get_options_t sym_get_options;
+       xbt_pfn_sym_get_sym_from_addr_t sym_get_sym_from_addr;
+       xbt_pfn_sym_set_options_t sym_set_options;
+       xbt_pfn_stack_walk_t stack_walk;
+}s_xbt_debug_hlp_t,* xbt_debug_hlp_t;
+
+
+/* the address to the unique reference to the debug help library interface */
+static xbt_debug_hlp_t 
+dbg_hlp = NULL;
+
+/* initialize the debug help library */
+static int
+dbg_hlp_init(HANDLE process_handle);
+
+/* finalize the debug help library */
+static int
+dbg_hlp_finalize(void);
+
+/*
+ * backtrace() function.
+ *
+ * Returns a backtrace for the calling program, in  the  array
+ * pointed  to  by  buffer.  A backtrace is the series of currently active
+ * function calls for the program.  Each item in the array pointed  to  by
+ * buffer  is  of  type  void *, and is the return address from the corre-
+ * sponding stack frame.  The size argument specifies the  maximum  number
+ * of  addresses that can be stored in buffer.  If the backtrace is larger
+ * than size, then the addresses corresponding to  the  size  most  recent
+ * function  calls  are  returned;  to obtain the complete backtrace, make
+ * sure that buffer and size are large enough.
+ */
+
+int 
+backtrace (void **buffer, int size);
+
+/*
+ * backtrace_symbols() function.
+ *
+ * Given the set of addresses returned by  backtrace()  in  buffer,  back-
+ * trace_symbols()  translates the addresses into an array of strings containing
+ * the name, the source file and the line number or the las called functions.
+ */
+char ** 
+backtrace_symbols (void *const *buffer, int size);
+
+/*
+ * backtrace_symbols_fd() function.
+ *
+ * Same as backtrace_symbols() function but, the the array of strings is wrotten
+ * in a file (fd is the file descriptor of this file)
+ */
+void 
+backtrace_symbols_fd(void *const *buffer, int size, int fd);
+#endif
 
 /* default __ex_ctx callback function */
 ex_ctx_t *__xbt_ex_ctx_default(void) {
+  /* Don't scream: this is a default which is never used (so, yes, 
+     there is one setjump container by running entity).
+
+     This default gets overriden in xbt/xbt_os_thread.c so that it works in
+     real life and in simulation when using threads to implement the simulation
+     processes (ie, with pthreads and on windows).
+
+     It also gets overriden in xbt/context.c when using ucontextes (as well as
+     in Java for now, but after the java overhaul, it will get cleaned out)
+  */
     static ex_ctx_t ctx = XBT_CTX_INITIALIZER;
 
     return &ctx;
 }
 
+/* Change raw libc symbols to file names and line numbers */
+void xbt_ex_setup_backtrace(xbt_ex_t *e);
+
+void xbt_backtrace_current(xbt_ex_t *e) {
+#if defined(HAVE_EXECINFO_H) && defined(HAVE_POPEN) && defined(ADDR2LINE) || (defined(WIN32) && defined(_M_IX86))
+  e->used     = backtrace((void**)e->bt,XBT_BACKTRACE_SIZE);
+  e->bt_strings = NULL;
+  xbt_ex_setup_backtrace(e);
+#endif
+}
+
+void xbt_backtrace_display(xbt_ex_t *e) {
+#if defined(HAVE_EXECINFO_H) && defined(HAVE_POPEN) && defined(ADDR2LINE) || (defined(WIN32) && defined(_M_IX86))
+  int i;
+
+  if (e->used == 0) {
+     fprintf(stderr,"(backtrace not set)\n");
+  } else {     
+     fprintf(stderr,"Backtrace (displayed in thread %p):\n",
+            (void*)xbt_thread_self());
+     for (i=1; i<e->used; i++) /* no need to display "xbt_display_backtrace" */
+       fprintf(stderr,"---> %s\n",e->bt_strings[i] +4);
+  }
+   
+  /* don't fool xbt_ex_free with uninitialized msg field */
+  e->msg=NULL;
+  e->remote=0;
+  xbt_ex_free(*e);
+#else 
+
+  ERROR0("No backtrace on this arch");
+#endif
+}
+
+/** \brief show the backtrace of the current point (lovely while debuging) */
+void xbt_backtrace_display_current(void) {
+  xbt_ex_t e;
+  xbt_backtrace_current(&e);
+  xbt_backtrace_display(&e);
+}
+
+#ifndef WIN32
+extern char **environ; /* the environment, as specified by the opengroup */
+#endif
+
+void xbt_ex_setup_backtrace(xbt_ex_t *e)  {
+#if defined(HAVE_EXECINFO_H) && defined(HAVE_POPEN) && defined(ADDR2LINE)
+  int i;
+  /* to get the backtrace from the libc */
+  char **backtrace = backtrace_symbols (e->bt, e->used);
+  
+  /* To build the commandline of addr2line */
+  char *cmd, *curr;
+  
+  /* to extract the addresses from the backtrace */
+  char **addrs=xbt_new(char*,e->used);
+  char buff[256],*p;
+  
+  /* To read the output of addr2line */
+  FILE *pipe;
+  char line_func[1024],line_pos[1024];
+
+  /* size (in char) of pointers on this arch */
+  int addr_len=0;
+
+  /* To search for the right executable path when not trivial */
+  struct stat stat_buf;
+  char *binary_name = NULL;
+   
+  /* Some arches only have stubs of backtrace, no implementation (hppa comes to mind) */
+  if (!e->used)
+     return;
+   
+  /* 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, ":");
+       unsigned int cpt;
+       char *data;
+       xbt_dynar_foreach(path, cpt, data) {
+         if (binary_name)
+           free(binary_name);
+         binary_name = bprintf("%s/%s",data,xbt_binary_name);
+         if (!stat(binary_name,&stat_buf)) {
+           /* Found. */
+           DEBUG1("Looked in the PATH for the binary. Found %s",binary_name);
+           xbt_dynar_free(&path);
+           break;
+         } 
+       }
+       if (stat(binary_name,&stat_buf)) {
+         /* not found */
+         e->used = 1;
+         e->bt_strings = xbt_new(char*,1);
+         e->bt_strings[0] = bprintf("(binary '%s' not found the path)",xbt_binary_name);
+         return;
+       }
+       xbt_dynar_free(&path);
+       break;
+      }        
+    }
+  } else {
+    binary_name = xbt_strdup(xbt_binary_name);
+  }      
+  cmd = curr = xbt_new(char,strlen(ADDR2LINE)+25+strlen(binary_name)+32*e->used);
+   
+  curr += sprintf(curr,"%s -f -e %s ",ADDR2LINE,binary_name);
+  free(binary_name);
+   
+  for (i=0; i<e->used;i++) {
+    /* retrieve this address */
+    DEBUG2("Retrieving address number %d from '%s'", i, backtrace[i]);
+    snprintf(buff,256,"%s",strchr(backtrace[i],'[')+1);
+    p=strchr(buff,']');
+    *p='\0';
+    if (strcmp(buff,"(nil)"))
+       addrs[i]=bprintf("%s", buff);
+    else
+       addrs[i]=bprintf("0x0");
+    DEBUG3("Set up a new address: %d, '%s'(%p)", i, addrs[i], addrs[i]);
+     
+    /* Add it to the command line args */
+    curr+=sprintf(curr,"%s ",addrs[i]);
+  } 
+  addr_len = strlen(addrs[0]);
+
+  /* parse the output and build a new backtrace */
+  e->bt_strings = xbt_new(char*,e->used);
+  
+  VERB1("Fire a first command: '%s'", cmd);
+  pipe = popen(cmd, "r");
+  if (!pipe) {
+    CRITICAL0("Cannot fork addr2line to display the backtrace");
+    abort();
+  }
+
+  for (i=0; i<e->used; i++) {
+    DEBUG2("Looking for symbol %d, addr = '%s'", i, addrs[i]); 
+    fgets(line_func,1024,pipe);
+    line_func[strlen(line_func)-1]='\0';
+    fgets(line_pos,1024,pipe);
+    line_pos[strlen(line_pos)-1]='\0';
+
+    if (strcmp("??",line_func)) {
+      DEBUG2("Found static symbol %s() at %s", line_func, line_pos);
+      e->bt_strings[i] = bprintf("**   In %s() at %s", line_func,line_pos);
+    } else {
+      /* Damn. The symbol is in a dynamic library. Let's get wild */
+      char *maps_name;
+      FILE *maps;
+      char maps_buff[512];
+
+      long int addr,offset=0;
+      char *p,*p2;
+
+      char *subcmd;
+      FILE *subpipe;
+      int found=0;
+
+      /* let's look for the offset of this library in our addressing space */
+      maps_name=bprintf("/proc/%d/maps",(int)getpid());
+      maps=fopen(maps_name,"r");
+
+      sscanf(addrs[i],"%lx",&addr);
+      sprintf(maps_buff,"%#lx",addr);
+      
+      if (strcmp(addrs[i],maps_buff)) {
+       CRITICAL2("Cannot parse backtrace address '%s' (addr=%#lx)",
+                 addrs[i], addr);
+      }
+      DEBUG2("addr=%s (as string) =%#lx (as number)",addrs[i],addr);
+
+      while (!found) {
+       long int first, last;
+       if (fgets(maps_buff,512,maps) == NULL) 
+         break;
+       if (i==0) {
+         maps_buff[strlen(maps_buff) -1]='\0';
+         DEBUG1("map line: %s", maps_buff);
+       }
+       sscanf(maps_buff,"%lx",&first);
+       p=strchr(maps_buff,'-')+1;
+       sscanf(p,"%lx",&last);
+       if (first < addr && addr < last) {
+         offset = first;
+         found=1;
+       }
+       if (found) {          
+          DEBUG3("%#lx in [%#lx-%#lx]", addr, first,last);
+          DEBUG0("Symbol found, map lines not further displayed (even if looking for next ones)");
+       }
+      }
+      fclose(maps);
+      free(maps_name);
+
+      if (!found) {
+       VERB0("Problem while reading the maps file. Following backtrace will be mangled.");
+       DEBUG1("No dynamic. Static symbol: %s", backtrace[i]);
+       e->bt_strings[i] = bprintf("**   In ?? (%s)", backtrace[i]);
+       continue;
+      }
+
+      /* Ok, Found the offset of the maps line containing the searched symbol. 
+        We now need to substract this from the address we got from backtrace.
+      */
+      
+      free(addrs[i]);
+      addrs[i] = bprintf("0x%0*lx",addr_len-2,addr-offset);
+      DEBUG2("offset=%#lx new addr=%s",offset,addrs[i]);
+
+      /* Got it. We have our new address. Let's get the library path and we 
+        are set */ 
+      p  = xbt_strdup(backtrace[i]);
+      if (p[0]=='[') {
+        /* library path not displayed in the map file either... */
+        free(p);
+        sprintf(line_func,"??");
+      } else {
+        p2 = strrchr(p,'(');
+        if (p2) *p2= '\0';
+        p2 = strrchr(p,' ');
+        if(p2) *p2= '\0';
+      
+        /* Here we go, fire an addr2line up */
+        subcmd = bprintf("%s -f -e %s %s",ADDR2LINE,p, addrs[i]);
+        free(p);
+        VERB1("Fire a new command: '%s'",subcmd);
+        subpipe = popen(subcmd,"r");
+        if (!subpipe) {
+           CRITICAL0("Cannot fork addr2line to display the backtrace");
+           abort();
+        }
+        fgets(line_func,1024,subpipe);
+        line_func[strlen(line_func)-1]='\0';
+        fgets(line_pos,1024,subpipe);
+        line_pos[strlen(line_pos)-1]='\0';
+        pclose(subpipe);
+        free(subcmd);
+      }
+
+      /* check whether the trick worked */
+      if (strcmp("??",line_func)) {
+       DEBUG2("Found dynamic symbol %s() at %s", line_func, line_pos);
+       e->bt_strings[i] = bprintf("**   In %s() at %s", line_func,line_pos);
+      } else {
+       /* damn, nothing to do here. Let's print the raw address */
+       DEBUG1("Dynamic symbol not found. Raw address = %s", backtrace[i]);
+       e->bt_strings[i] = bprintf("**   In ?? at %s", backtrace[i]);
+      }
+      
+    }
+    free(addrs[i]);
+     
+    /* Mask the bottom of the stack */    
+    if (!strncmp("main",line_func,strlen("main")) ||
+       !strncmp("xbt_thread_context_wrapper",line_func,strlen("xbt_thread_context_wrapper"))) {
+       int j;
+       for (j=i+1; j<e->used; j++)
+        free(addrs[j]);
+       e->used = i;
+
+       if (!strncmp("xbt_thread_context_wrapper",line_func,strlen("xbt_thread_context_wrapper"))) {
+         e->used++;
+         e->bt_strings[i] = bprintf("**   (in a separate thread)");
+       }       
+    }
+     
+    
+  }
+  pclose(pipe);
+  free(addrs);
+  free(backtrace);
+  free(cmd);
+#elif (defined(WIN32) && defined (_M_IX86))
+int i;
+  /* to get the backtrace from the libc */
+  char **backtrace = backtrace_symbols (e->bt, e->used);
+  
+  /* parse the output and build a new backtrace */
+  e->bt_strings = xbt_new(char*,e->used);
+  
+
+  for(i=0; i<e->used; i++) 
+  {
+      e->bt_strings[i] = strdup(backtrace[i]);
+      free(backtrace[i]);
+  }
+  
+  free(backtrace);
+#endif
+}    
+
 /** @brief shows an exception content and the associated stack if available */
 void xbt_ex_display(xbt_ex_t *e)  {
+  char *thrower=NULL;
+
+  if (e->remote)
+    thrower = bprintf(" on host %s(%d)",e->host,e->pid);
 
   fprintf(stderr,
-         "** SimGrid: UNCAUGHT EXCEPTION on %s: category: %s; value: %d\n"
+         "** SimGrid: UNCAUGHT EXCEPTION received on %s(%d): category: %s; value: %d\n"
          "** %s\n"
-         "** Thrown by %s%s%s at %s:%d:%s\n",
-         gras_os_myname(),
+         "** Thrown by %s()%s\n",
+         gras_os_myname(),(*xbt_getpid)(),
          xbt_ex_catname(e->category), e->value, e->msg,
-         e->procname, (e->host?"@":""),(e->host?e->host:""),//localhost"),
-         e->file,e->line,e->func);
+         e->procname,thrower?thrower:" in this process");
+  CRITICAL1("%s",e->msg);
 
-#ifdef HAVE_EXECINFO_H
- {
-  int i;
+  if (thrower)
+    free(thrower);
 
-  fprintf(stderr,"** Backtrace:\n");
-  if (!e->bt_strings)
-    e->bt_strings = backtrace_symbols (e->bt, e->used);
+  if (!e->remote && !e->bt_strings)
+    xbt_ex_setup_backtrace(e);
 
-  for (i = 0; i < e->used; i++)
-     printf ("   %s\n", e->bt_strings[i]);
- }
+#if (defined(HAVE_EXECINFO_H) && defined(HAVE_POPEN) && defined(ADDR2LINE)) || (defined(WIN32) && defined(_M_IX86))
+  /* We have everything to build neat backtraces */
+  {
+    int i;
+    
+    fprintf(stderr,"\n");
+    for (i=0; i<e->used; i++)
+      fprintf(stderr,"%s\n",e->bt_strings[i]);
+    
+  }
+#else
+  fprintf(stderr," at %s:%d:%s (no backtrace available on that arch)\n",  
+         e->file,e->line,e->func);
 #endif
+  xbt_ex_free(*e);
 }
 
 
@@ -79,28 +489,27 @@ void __xbt_ex_terminate_default(xbt_ex_t *e)  {
 }
 
 /* the externally visible API */
-ex_ctx_cb_t  __xbt_ex_ctx       = &__xbt_ex_ctx_default;
-ex_term_cb_t __xbt_ex_terminate = &__xbt_ex_terminate_default;
+XBT_EXPORT_NO_IMPORT(ex_ctx_cb_t)  __xbt_ex_ctx       = &__xbt_ex_ctx_default;
+XBT_EXPORT_NO_IMPORT(ex_term_cb_t) __xbt_ex_terminate = &__xbt_ex_terminate_default;
+
 
 void xbt_ex_free(xbt_ex_t e) {
   int i;
 
   if (e.msg) free(e.msg);
-  free(e.procname);
   if (e.remote) {
+    free(e.procname);
     free(e.file);
     free(e.func);
-    if (e.bt_strings) /* FIXME: should never be NULL... */
-      for (i=0; i<e.used; i++) 
-       free(e.bt_strings[i]);
-    free(e.bt_strings);
-    e.bt_strings=NULL;
     free(e.host);
   }
-  /* locally, only one chunk of memory is allocated by the libc */
-  if (e.bt_strings)
-    free(e.bt_strings);
 
+  if (e.bt_strings) {  
+     for (i=0; i<e.used; i++) 
+       free((char*)e.bt_strings[i]);
+     free((char **)e.bt_strings);
+  }
+  /* memset(e,0,sizeof(xbt_ex_t)); */
 }
 
 /** \brief returns a short name for the given exception category */
@@ -119,14 +528,373 @@ const char * xbt_ex_catname(xbt_errcat_t cat) {
 }
 
 #ifndef HAVE_EXECINFO_H
+#  if (defined(WIN32) && defined(_M_IX86))
+int 
+backtrace (void **buffer, int size)
+{
+       int pos = 0;
+       STACKFRAME* stack_frame;
+       int first = 1;
+
+       CONTEXT context = {CONTEXT_FULL};
+       GetThreadContext(GetCurrentThread(), &context);
+       
+       /* ebp pointe sur la base de la pile */
+       /* esp pointe sur le stack pointer <=> sur le dernier élément déposé dans la pile (l'élément courant) */
+       _asm call $+5
+       _asm pop eax 
+       _asm mov context.Eip, eax 
+       _asm mov eax, esp 
+       _asm mov context.Esp, eax 
+       _asm mov context.Ebp, ebp 
+
+       dbg_hlp_init(GetCurrentProcess());
+       
+       if((NULL == dbg_hlp) || (size <= 0) || (NULL == buffer))
+       {
+               errno = EINVAL;
+               return 0;
+       }
+
+       for(pos = 0; pos < size; pos++)
+               buffer[pos] = NULL;
+       
+       pos = 0;
+
+    while(pos < size)
+    {
+               stack_frame = (void*)calloc(1,sizeof(STACKFRAME));
+               
+               if(!stack_frame)
+               {
+                       errno = ENOMEM;
+                       break;
+               }
+               
+               stack_frame->AddrPC.Offset = context.Eip;
+           stack_frame->AddrPC.Mode = AddrModeFlat;
+       
+           stack_frame->AddrFrame.Offset = context.Ebp;
+           stack_frame->AddrFrame.Mode = AddrModeFlat;
+       
+           stack_frame->AddrStack.Offset = context.Esp;
+           stack_frame->AddrStack.Mode = AddrModeFlat;
+               
+               if((*(dbg_hlp->stack_walk))(
+                                       IMAGE_FILE_MACHINE_I386,
+                                       dbg_hlp->process_handle,
+                                       GetCurrentThread(),
+                                       stack_frame, 
+                                       &context,
+                                       NULL,
+                                       dbg_hlp->sym_function_table_access,
+                                       dbg_hlp->sym_get_module_base,
+                                       NULL)
+                       && !first) 
+               {
+                       if(stack_frame->AddrReturn.Offset)
+                               buffer[pos++] = (void*)stack_frame;
+                       else
+                       {
+                               free(stack_frame); /* no symbol */
+                               break;
+                       }
+               }
+               else
+               {
+                       free(stack_frame);
+
+                       if(first)
+                               first = 0;
+                       else
+                               break;
+               }               
+    }
+
+    return pos;
+}
+
+char ** 
+backtrace_symbols (void *const *buffer, int size)
+{
+       int pos;
+       int success = 0;        
+       char** strings;
+       STACKFRAME* stack_frame;
+       char str[MAX_SYM_NAME] = {0};
+       IMAGEHLP_SYMBOL * pSym;
+       unsigned long displacement = 0;
+       IMAGEHLP_LINE line_info = {0};
+       IMAGEHLP_MODULE module = {0};
+       byte __buffer[(sizeof(SYMBOL_INFO) +MAX_SYM_NAME * sizeof(TCHAR) + sizeof(ULONG64) - 1) / sizeof(ULONG64)];
+
+       if((NULL == dbg_hlp) || (size <= 0) || (NULL == buffer))
+       {
+               errno = EINVAL;
+               return NULL;
+       }
+       
+       strings = (char**)calloc(size,sizeof(char*));
+       
+       if(NULL == strings)
+       {
+               errno = ENOMEM;
+               return NULL;
+       }
+       
+       pSym = (IMAGEHLP_SYMBOL*)__buffer;
+
+       pSym->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL);
+       pSym->MaxNameLength = MAX_SYM_NAME;
+
+
+       line_info.SizeOfStruct = sizeof(IMAGEHLP_LINE);
+       module.SizeOfStruct = sizeof(IMAGEHLP_MODULE);
+       
+       for(pos = 0; pos < size; pos++)
+       {
+               stack_frame = (STACKFRAME*)(buffer[pos]);
+
+               if(NULL != stack_frame)
+               {
+               
+                       if((*(dbg_hlp->sym_get_sym_from_addr))(dbg_hlp->process_handle,stack_frame->AddrPC.Offset, &displacement,pSym))
+                       {       
+                               if((*(dbg_hlp->sym_get_line_from_addr))(dbg_hlp->process_handle,stack_frame->AddrPC.Offset, &displacement,&line_info))
+                               {
+                                       
+                                               sprintf(str,"**   In %s() at %s:%d", pSym->Name,line_info.FileName,line_info.LineNumber); 
+                                               
+                                               strings[pos] = strdup(str);
+                                               memset(str,0,MAX_SYM_NAME);     
+                                       
+                                               success = 1;
+                               }
+                       }
+
+                       free(stack_frame);
+               }
+               else
+                       break;
+       }
+       
+       if(!success)
+       {
+               free(strings);
+               strings = NULL;
+       }
+
+       dbg_hlp_finalize();
+       
+       return strings;
+}
+
+void
+backtrace_symbols_fd(void *const *buffer, int size, int fd)
+{
+       int pos;
+       int success = 0;        
+       STACKFRAME* stack_frame;
+       char str[MAX_SYM_NAME] = {0};
+       IMAGEHLP_SYMBOL * pSym;
+       unsigned long displacement = 0;
+       IMAGEHLP_LINE line_info = {0};
+       IMAGEHLP_MODULE module = {0};
+
+       byte __buffer[(sizeof(SYMBOL_INFO) +MAX_SYM_NAME * sizeof(TCHAR) + sizeof(ULONG64) - 1) / sizeof(ULONG64)];
+
+       if((NULL == dbg_hlp) || (size <= 0) || (NULL == buffer) || (-1 == fd))
+       {
+               errno = EINVAL;
+               return;
+       }
+       
+       pSym = (IMAGEHLP_SYMBOL*)__buffer;
+
+       pSym->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL);
+       pSym->MaxNameLength = MAX_SYM_NAME;
+
+
+       line_info.SizeOfStruct = sizeof(IMAGEHLP_LINE);
+       module.SizeOfStruct = sizeof(IMAGEHLP_MODULE);
+       
+       for(pos = 0; pos < size; pos++)
+       {
+               stack_frame = (STACKFRAME*)(buffer[pos]);
+
+               if(NULL != stack_frame)
+               {
+               
+                       if((*(dbg_hlp->sym_get_sym_from_addr))(dbg_hlp->process_handle,stack_frame->AddrPC.Offset, &displacement,pSym))
+                       {       
+                               if((*(dbg_hlp->sym_get_line_from_addr))(dbg_hlp->process_handle,stack_frame->AddrPC.Offset, &displacement,&line_info))
+                               {
+                                       
+                                               
+                                               sprintf(str,"**   In %s() at %s:%d\n", pSym->Name,line_info.FileName,line_info.LineNumber); 
+                                               
+                                               if(-1 == write(fd,str,strlen(str)))
+                                                       break;
+
+                                               memset(str,0,MAX_SYM_NAME);     
+                                       
+                                               success = 1;
+                               }
+                       }
+
+                       free(stack_frame);
+               }
+               else
+                       break;
+       }
+       
+       dbg_hlp_finalize();
+       
+}
+
+static int
+dbg_hlp_init(HANDLE process_handle)
+{
+       if(dbg_hlp)
+       {
+               /* debug help is already loaded */
+               return 0;
+       }
+
+       /* allocation */
+       dbg_hlp = (xbt_debug_hlp_t)calloc(1,sizeof(s_xbt_debug_hlp_t));
+       
+       if(!dbg_hlp)
+               return ENOMEM;
+       
+       /* load the library */
+       dbg_hlp->instance = LoadLibraryA("Dbghelp.dll");
+       
+       if(!(dbg_hlp->instance))
+       {
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();
+       }
+       
+       /* get the pointers to debug help library exported functions */
+       
+       if(!((dbg_hlp->sym_initialize) = (xbt_pfn_sym_initialize_t)GetProcAddress(dbg_hlp->instance,"SymInitialize")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+               
+       if(!((dbg_hlp->sym_cleanup) = (xbt_pfn_sym_cleanup_t)GetProcAddress(dbg_hlp->instance,"SymCleanup")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_function_table_access) = (xbt_pfn_sym_function_table_access_t)GetProcAddress(dbg_hlp->instance,"SymFunctionTableAccess")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_get_line_from_addr) = (xbt_pfn_sym_get_line_from_addr_t)GetProcAddress(dbg_hlp->instance,"SymGetLineFromAddr")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_get_module_base) = (xbt_pfn_sym_get_module_base_t)GetProcAddress(dbg_hlp->instance,"SymGetModuleBase")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_get_options) = (xbt_pfn_sym_get_options_t)GetProcAddress(dbg_hlp->instance,"SymGetOptions")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_get_sym_from_addr) = (xbt_pfn_sym_get_sym_from_addr_t)GetProcAddress(dbg_hlp->instance,"SymGetSymFromAddr")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->sym_set_options) = (xbt_pfn_sym_set_options_t)GetProcAddress(dbg_hlp->instance,"SymSetOptions")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       if(!((dbg_hlp->stack_walk) = (xbt_pfn_stack_walk_t)GetProcAddress(dbg_hlp->instance,"StackWalk")))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();     
+       }
+       
+       dbg_hlp->process_handle = process_handle;
+
+       (*(dbg_hlp->sym_set_options))((*(dbg_hlp->sym_get_options))() | SYMOPT_LOAD_LINES | SYMOPT_DEFERRED_LOADS);
+       
+       if(!(*(dbg_hlp->sym_initialize))(dbg_hlp->process_handle,0,1))
+       {
+               FreeLibrary(dbg_hlp->instance);
+               free(dbg_hlp);
+               dbg_hlp = NULL;
+               return (int)GetLastError();
+       }
+               
+       
+       return 0;
+}
+
+static int
+dbg_hlp_finalize(void)
+{
+       if(!dbg_hlp)
+               return EINVAL;
+               
+       if(!(*(dbg_hlp->sym_cleanup))(dbg_hlp->process_handle))
+               return (int)GetLastError();
+       
+       if(!FreeLibrary(dbg_hlp->instance))
+               return (int)GetLastError();
+       
+       free(dbg_hlp);
+       dbg_hlp = NULL;
+       
+       return 0;
+}
+#  endif
+#else
 /* dummy implementation. We won't use the result, but ex.h needs it to be defined */
 int backtrace (void **__array, int __size) {
-  return 0;
+  return 0;    
 }
 
 #endif
 
 #ifdef SIMGRID_TEST
+#include <stdio.h>
 #include "xbt/ex.h"
 
 XBT_TEST_SUITE("xbt_ex","Exception Handling");
@@ -148,20 +916,33 @@ XBT_TEST_UNIT("controlflow",test_controlflow, "basic nested control flow") {
             THROW0(unknown_error,0,"something");
         } CATCH (ex) {
             if (n != 3)
-                xbt_test_fail1("M3: n=%d (!= 1)", n);
+                xbt_test_fail1("M3: n=%d (!= 3)", n);
+            n++;
+           xbt_ex_free(ex);
+        }
+       n++;
+        TRY {
+            if (n != 5)
+                xbt_test_fail1("M2: n=%d (!= 5)", n);
+            n++;
+            THROW0(unknown_error,0,"something");
+        } CATCH (ex) {
+            if (n != 6)
+                xbt_test_fail1("M3: n=%d (!= 6)", n);
             n++;
             RETHROW;
+            n++;
         }
         xbt_test_fail1("MX: n=%d (shouldn't reach this point)", n);
     }
     CATCH(ex) {
-        if (n != 4)
-            xbt_test_fail1("M4: n=%d (!= 4)", n);
+        if (n != 7)
+            xbt_test_fail1("M4: n=%d (!= 7)", n);
         n++;
         xbt_ex_free(ex);
     }
-    if (n != 5)
-        xbt_test_fail1("M5: n=%d (!= 5)", n);
+    if (n != 8)
+        xbt_test_fail1("M5: n=%d (!= 8)", n);
 }
 
 XBT_TEST_UNIT("value",test_value,"exception value passing") {
@@ -269,9 +1050,10 @@ static void bad_example(void) {
   /* end_of_bad_example */
 }
 #endif
-
+typedef struct {char *first;} global_context_t;
+   
 static void good_example(void) {
-  struct {char*first;} *globalcontext;
+  global_context_t *global_context=malloc(sizeof(global_context_t));
   xbt_ex_t ex;
 
   /* GOOD_EXAMPLE */
@@ -281,7 +1063,7 @@ static void good_example(void) {
     char * volatile /*03*/ cp3 = NULL /*02*/;
     TRY {
       cp1 = mallocex(SMALLAMOUNT);
-      globalcontext->first = cp1;
+      global_context->first = cp1;
       cp1 = NULL /*05 give away*/;
       cp2 = mallocex(TOOBIG);
       cp3 = mallocex(SMALLAMOUNT);