X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/38f7ddbf61f574a934f191ef2d8358d9f8be1f96..9880c25e78b6adb391bd15a516d4966b3f0a951b:/src/xbt/backtrace.cpp diff --git a/src/xbt/backtrace.cpp b/src/xbt/backtrace.cpp index 022ae52a55..a74145f90a 100644 --- a/src/xbt/backtrace.cpp +++ b/src/xbt/backtrace.cpp @@ -1,44 +1,46 @@ -/* Copyright (c) 2005-2017. 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 #include #include - +#include +#include +#include #include -// Try to detect and use the C++ intanium ABI for name demangling: +#include + +// Try to detect and use the C++ itanium ABI for name demangling: #ifdef __GXX_ABI_VERSION #include #endif +#if HAVE_EXECINFO_H +#include +#endif #include "simgrid/simix.h" /* SIMIX_process_self_get_name() */ -#include #include #include +#include #include -#include "src/internal_config.h" - -extern "C" { - 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) +void xbt_backtrace_display(const simgrid::xbt::Backtrace& bt) { -#ifdef HAVE_BACKTRACE - std::vector backtrace = simgrid::xbt::resolveBacktrace(loc, count); + std::vector backtrace = simgrid::xbt::resolve_backtrace(bt); if (backtrace.empty()) { - fprintf(stderr, "(backtrace not set)\n"); + 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()); @@ -51,20 +53,24 @@ void xbt_backtrace_display(xbt_backtrace_location_t* loc, std::size_t count) startWith(s, "simgrid::xbt::MainFunction") /* main used with thread factory */) break; } -#else - XBT_ERROR("Cannot display backtrace when compiled without libunwind."); -#endif } /** @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]; - size_t used = xbt_backtrace_current(bt, size); - xbt_backtrace_display(bt, used); + simgrid::xbt::Backtrace bt = simgrid::xbt::backtrace(); + xbt_backtrace_display(bt); } +#if HAVE_BACKTRACE +// For some reason, if I try to use it directly, GCC thinks I try to use xbt::backtrace. +// I suspect that this symbol is not presented as a regular function in execinfo.h +static int gnu_backtrace(simgrid::xbt::Backtrace& bt) +{ + return backtrace(bt.data(), bt.size()); +} +#endif + namespace simgrid { namespace xbt { @@ -84,19 +90,259 @@ std::unique_ptr demangle(const char* name) return std::unique_ptr(xbt_strdup(name), std::free); } -std::vector backtrace() +Backtrace backtrace() { - const std::size_t size = 10; - xbt_backtrace_location_t loc[size]; - size_t used = xbt_backtrace_current(loc, size); - return std::vector(loc, loc + used); + simgrid::xbt::Backtrace res; +#if HAVE_BACKTRACE + res.resize(15); + int used = gnu_backtrace(res); + 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); + } + res.shrink_to_fit(); +#endif + return res; } +} // namespace xbt +} // namespace simgrid + +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 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 resolve_backtrace(const Backtrace& bt) +{ + std::vector result; #if HAVE_BACKTRACE && HAVE_EXECINFO_H && HAVE_POPEN && defined(ADDR2LINE) -# include "src/xbt/backtrace_linux.cpp" -#else -# include "src/xbt/backtrace_dummy.cpp" -#endif + // FIXME: This code could be greatly improved/simplified with + // http://cairo.sourcearchive.com/documentation/1.9.4/backtrace-symbols_8c-source.html + if (bt.size() == 0) + return result; + + if (xbt_binary_name == nullptr) + XBT_WARN("XBT not initialized, the backtrace will not be resolved."); + + char** backtrace_syms = backtrace_symbols(bt.data(), bt.size()); + std::string binary_name = get_binary_path(); + + if (binary_name.empty()) { + for (std::size_t i = 1; i < bt.size(); i++) // the first one is not interesting + result.push_back(simgrid::xbt::string_printf("%p", bt[i])); + return result; + } + + // Create the system command for add2line: + std::ostringstream stream; + stream << ADDR2LINE << " -f -e " << binary_name << ' '; + std::vector addrs(bt.size()); + for (std::size_t i = 1; i < bt.size(); i++) { // the first one is not interesting + /* 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 = 1; i < bt.size(); i++) { // The first one is not interesting + 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, bt[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, bt[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