X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/acc4596bfe40a4bf7f59d5b94bc5643f86806dda..4bbdef278b030346b003663a70ce6e0ea459ee32:/src/xbt/backtrace.cpp

diff --git a/src/xbt/backtrace.cpp b/src/xbt/backtrace.cpp
index f897e12adb..ed512992a3 100644
--- a/src/xbt/backtrace.cpp
+++ b/src/xbt/backtrace.cpp
@@ -1,20 +1,62 @@
-/* Copyright (c) 2005-2016. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2005-2018. The SimGrid Team. 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 "src/internal_config.h"
 
 #include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <fstream>
+#include <sstream>
+#include <sys/stat.h>
+#include <vector>
 
-#include <xbt/log.h>
-#include <xbt/backtrace.h>
+#include <boost/algorithm/string.hpp>
 
-#include "src/internal_config.h"
+// Try to detect and use the C++ itanium ABI for name demangling:
+#ifdef __GXX_ABI_VERSION
+#include <cxxabi.h>
+#endif
+#if HAVE_EXECINFO_H
+#include <execinfo.h>
+#endif
 
-extern "C" {
+#include "simgrid/simix.h" /* SIMIX_process_self_get_name() */
+#include <xbt/backtrace.hpp>
+#include <xbt/log.h>
+#include <xbt/string.hpp>
+#include <xbt/sysdep.h>
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_backtrace, xbt, "Backtrace");
 
+static bool startWith(std::string str, const char* prefix)
+{
+  return strncmp(str.c_str(), prefix, strlen(prefix)) == 0;
+}
+
+void xbt_backtrace_display(xbt_backtrace_location_t* loc, std::size_t count)
+{
+  std::vector<std::string> backtrace = simgrid::xbt::resolve_backtrace(loc, count);
+  if (backtrace.empty()) {
+    fprintf(stderr, "(backtrace not set -- maybe unavailable on this architecture?)\n");
+    return;
+  }
+  fprintf(stderr, "Backtrace (displayed in process %s):\n", SIMIX_process_self_get_name());
+  for (std::string const& s : backtrace) {
+    if (startWith(s, "xbt_backtrace_display_current"))
+      continue;
+
+    std::fprintf(stderr, "---> '%s'\n", s.c_str());
+    if (startWith(s, "SIMIX_simcall_handle") ||
+        startWith(s, "simgrid::xbt::MainFunction") /* main used with thread factory */)
+      break;
+  }
 }
 
-/** @brief show the backtrace of the current point (lovely while debuging) */
-void xbt_backtrace_display_current(void)
+/** @brief show the backtrace of the current point (lovely while debugging) */
+void xbt_backtrace_display_current()
 {
   const std::size_t size = 10;
   xbt_backtrace_location_t bt[size];
@@ -22,8 +64,288 @@ void xbt_backtrace_display_current(void)
   xbt_backtrace_display(bt, used);
 }
 
-#if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
-# include "src/xbt/backtrace_linux.cpp"
-#else
-# include "src/xbt/backtrace_dummy.cpp"
+namespace simgrid {
+namespace xbt {
+
+std::unique_ptr<char, void(*)(void*)> demangle(const char* name)
+{
+#ifdef __GXX_ABI_VERSION
+  int status;
+  auto res = std::unique_ptr<char, void(*)(void*)>(
+    abi::__cxa_demangle(name, nullptr, nullptr, &status),
+    std::free
+  );
+  if (res != nullptr)
+    return res;
+  // We did not manage to resolve this. Probably because this is not a mangled symbol:
 #endif
+  // Return the symbol:
+  return std::unique_ptr<char, void(*)(void*)>(xbt_strdup(name), std::free);
+}
+
+Backtrace backtrace()
+{
+  const std::size_t size = 10;
+  xbt_backtrace_location_t loc[size];
+  size_t used = xbt_backtrace_current(loc, size);
+  return Backtrace(loc, loc + used);
+}
+
+}
+}
+
+size_t xbt_backtrace_current(xbt_backtrace_location_t* loc, std::size_t count)
+{
+  std::size_t used = 0;
+#if HAVE_BACKTRACE
+  used = backtrace(loc, count);
+  if (used == 0) {
+    std::fprintf(stderr, "The backtrace() function failed, which probably means that the memory is exhausted\n.");
+    std::fprintf(stderr, "Bailing out now since there is nothing I can do without a decent amount of memory\n.");
+    std::fprintf(stderr, "Please go fix the memleaks\n");
+    std::exit(1);
+  }
+#endif
+  return used;
+}
+
+namespace simgrid {
+namespace xbt {
+
+/** Find the path of the binary file from the name found in argv */
+static std::string get_binary_path()
+{
+  struct stat stat_buf;
+
+  if (xbt_binary_name == nullptr)
+    return "";
+
+  // We found it, we are happy:
+  if (stat(xbt_binary_name, &stat_buf) == 0)
+    return xbt_binary_name;
+
+  // Not found, look in the PATH:
+  char* path = getenv("PATH");
+  if (path == nullptr)
+    return "";
+
+  XBT_DEBUG("Looking in the PATH: %s\n", path);
+  std::vector<std::string> path_list;
+  boost::split(path_list, path, boost::is_any_of(":;"));
+
+  for (std::string const& path_item : path_list) {
+    std::string binary_name = simgrid::xbt::string_printf("%s/%s", path_item.c_str(), xbt_binary_name);
+    bool found              = (stat(binary_name.c_str(), &stat_buf) == 0);
+    XBT_DEBUG("Looked in the PATH for the binary. %s %s", found ? "Found" : "Not found", binary_name.c_str());
+    if (found)
+      return binary_name;
+  }
+
+  // Not found at all:
+  return "";
+}
+
+std::vector<std::string> resolve_backtrace(xbt_backtrace_location_t const* loc, std::size_t count)
+{
+  std::vector<std::string> result;
+
+#if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE)
+  // FIXME: This code could be greatly improved/simplified with
+  //   http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html
+  if (count == 0)
+    return result;
+
+  if (xbt_binary_name == nullptr)
+    XBT_WARN("XBT not initialized, the backtrace will not be resolved.");
+
+  // Drop the first one:
+  loc++;
+  count--;
+
+  char** backtrace_syms   = backtrace_symbols(loc, count);
+  std::string binary_name = get_binary_path();
+
+  if (binary_name.empty()) {
+    for (std::size_t i = 0; i < count; i++)
+      result.push_back(simgrid::xbt::string_printf("%p", loc[i]));
+    return result;
+  }
+
+  // Create the system command for add2line:
+  std::ostringstream stream;
+  stream << ADDR2LINE << " -f -e " << binary_name << ' ';
+  std::vector<std::string> addrs(count);
+  for (std::size_t i = 0; i < count; i++) {
+    /* retrieve this address */
+    XBT_DEBUG("Retrieving address number %zu from '%s'", i, backtrace_syms[i]);
+    char buff[256];
+    snprintf(buff, 256, "%s", strchr(backtrace_syms[i], '[') + 1);
+    char* p = strchr(buff, ']');
+    *p      = '\0';
+    if (strcmp(buff, "(nil)"))
+      addrs[i] = buff;
+    else
+      addrs[i] = "0x0";
+    XBT_DEBUG("Set up a new address: %zu, '%s'", i, addrs[i].c_str());
+    /* Add it to the command line args */
+    stream << addrs[i] << ' ';
+  }
+  std::string cmd = stream.str();
+
+  /* size (in char) of pointers on this arch */
+  int addr_len = addrs[0].size();
+
+  XBT_VERB("Fire a first command: '%s'", cmd.c_str());
+  FILE* pipe = popen(cmd.c_str(), "r");
+  xbt_assert(pipe, "Cannot fork addr2line to display the backtrace");
+
+  /* To read the output of addr2line */
+  char line_func[1024];
+  char line_pos[1024];
+  for (std::size_t i = 0; i < count; i++) {
+    XBT_DEBUG("Looking for symbol %zu, addr = '%s'", i, addrs[i].c_str());
+    if (fgets(line_func, 1024, pipe)) {
+      line_func[strlen(line_func) - 1] = '\0';
+    } else {
+      XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
+      strncpy(line_func, "???", 4);
+    }
+    if (fgets(line_pos, 1024, pipe)) {
+      line_pos[strlen(line_pos) - 1] = '\0';
+    } else {
+      XBT_VERB("Cannot run fgets to look for symbol %zu, addr %s", i, addrs[i].c_str());
+      strncpy(line_pos, backtrace_syms[i], 1024);
+    }
+
+    if (strcmp("??", line_func) != 0) {
+      auto name = simgrid::xbt::demangle(line_func);
+      XBT_DEBUG("Found static symbol %s at %s", name.get(), line_pos);
+      result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
+    } else {
+      /* Damn. The symbol is in a dynamic library. Let's get wild */
+
+      unsigned long int offset = 0;
+      int found                = 0;
+
+      /* let's look for the offset of this library in our addressing space */
+      std::string maps_name = std::string("/proc/") + std::to_string(getpid()) + "/maps";
+      std::ifstream maps(maps_name);
+      if (not maps) {
+        XBT_CRITICAL("open(\"%s\") failed: %s", maps_name.c_str(), strerror(errno));
+        continue;
+      }
+      size_t pos;
+      unsigned long int addr = std::stoul(addrs[i], &pos, 16);
+      if (pos != addrs[i].length()) {
+        XBT_CRITICAL("Cannot parse backtrace address '%s' (addr=%#lx)", addrs[i].c_str(), addr);
+      }
+      XBT_DEBUG("addr=%s (as string) =%#lx (as number)", addrs[i].c_str(), addr);
+
+      while (not found) {
+        unsigned long int first;
+        unsigned long int last;
+
+        std::string maps_buff;
+        if (not std::getline(maps, maps_buff))
+          break;
+        if (i == 0) {
+          XBT_DEBUG("map line: %s", maps_buff.c_str());
+        }
+        first = std::stoul(maps_buff, &pos, 16);
+        maps_buff.erase(0, pos + 1);
+        last = std::stoul(maps_buff, nullptr, 16);
+        if (first < addr && addr < last) {
+          offset = first;
+          found  = 1;
+        }
+        if (found) {
+          XBT_DEBUG("%#lx in [%#lx-%#lx]", addr, first, last);
+          XBT_DEBUG("Symbol found, map lines not further displayed (even if looking for next ones)");
+        }
+      }
+      maps.close();
+      addrs[i].clear();
+
+      if (not found) {
+        XBT_VERB("Problem while reading the maps file. Following backtrace will be mangled.");
+        XBT_DEBUG("No dynamic. Static symbol: %s", backtrace_syms[i]);
+        result.push_back(simgrid::xbt::string_printf("?? (%s)", backtrace_syms[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.
+       */
+
+      addrs[i] = simgrid::xbt::string_printf("0x%0*lx", addr_len - 2, addr - offset);
+      XBT_DEBUG("offset=%#lx new addr=%s", offset, addrs[i].c_str());
+
+      /* Got it. We have our new address. Let's get the library path and we are set */
+      std::string p(backtrace_syms[i]);
+      if (p[0] == '[') {
+        /* library path not displayed in the map file either... */
+        snprintf(line_func, 3, "??");
+      } else {
+        size_t p2 = p.find_first_of("( ");
+        if (p2 != std::string::npos)
+          p.erase(p2);
+
+        /* Here we go, fire an addr2line up */
+        std::string subcmd = std::string(ADDR2LINE) + " -f -e " + p + " " + addrs[i];
+        XBT_VERB("Fire another command: '%s'", subcmd.c_str());
+        FILE* subpipe = popen(subcmd.c_str(), "r");
+        if (not subpipe) {
+          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.c_str());
+          strncpy(line_func, "???", 4);
+        }
+        if (fgets(line_pos, 1024, subpipe)) {
+          line_pos[strlen(line_pos) - 1] = '\0';
+        } else {
+          XBT_VERB("Cannot read result of subcommand %s", subcmd.c_str());
+          strncpy(line_pos, backtrace_syms[i], 1024);
+        }
+        pclose(subpipe);
+      }
+
+      /* check whether the trick worked */
+      if (strcmp("??", line_func)) {
+        auto name = simgrid::xbt::demangle(line_func);
+        XBT_DEBUG("Found dynamic symbol %s at %s", name.get(), line_pos);
+        result.push_back(simgrid::xbt::string_printf("%s at %s, %p", name.get(), line_pos, loc[i]));
+      } else {
+        /* damn, nothing to do here. Let's print the raw address */
+        XBT_DEBUG("Dynamic symbol not found. Raw address = %s", backtrace_syms[i]);
+        result.push_back(simgrid::xbt::string_printf("?? at %s", backtrace_syms[i]));
+      }
+    }
+    addrs[i].clear();
+
+    /* Mask the bottom of the stack */
+    const char* const breakers[] = {
+        "main",
+        "_ZN7simgrid6kernel7context13ThreadContext7wrapperE", // simgrid::kernel::context::ThreadContext::wrapper
+        "_ZN7simgrid6kernel7context8UContext7wrapperE"        // simgrid::kernel::context::UContext::wrapper
+    };
+    bool do_break = false;
+    for (const char* b : breakers) {
+      if (strncmp(b, line_func, strlen(b)) == 0) {
+        do_break = true;
+        break;
+      }
+    }
+    if (do_break)
+      break;
+  }
+  pclose(pipe);
+  xbt_free(backtrace_syms);
+#endif /* ADDR2LINE usable to resolve the backtrace */
+  return result;
+}
+
+} // namespace xbt
+} // namespace simgrid