testrt.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define LINE_SIZE 255

#include <limits.h>
#ifndef LIBC6_ARCH
#  if (__WORDSIZE == 64)
#    define LIBC6_ARCH "libc6,x86-64"
#  else
#    define LIBC6_ARCH "libc6"
#  endif
#endif


int main(int argc, char *argv[])
{
  int ret;
  FILE *f;
  char command[LINE_SIZE];
  char stdcxx_sys_lib[LINE_SIZE], gcc_sys_lib[LINE_SIZE];
  char stdcxx_sys_sym[LINE_SIZE], gcc_sys_sym[LINE_SIZE];
  char stdcxx_bundle_sym[LINE_SIZE], gcc_bundle_sym[LINE_SIZE];
  int stdcxx_sys_ver=1, stdcxx_bundle_ver=0, gcc_sys_ver=1, gcc_bundle_ver=0;

  char *stdcxx_bundle_lib = "./optional/libstdc++/libstdc++.so.6";
  char *gcc_bundle_lib = "./optional/libgcc/libgcc_s.so.1";
  const char *format = "tr '\\0' '\\n' < '%s' | grep -e '%s' | tail -n1";

#define SCANLIB(lib,sym,regex) \
  sprintf(command, format, lib, regex); \
  f = popen(command, "r"); \
  ret = fscanf(f, "%s", sym); (void)ret; \
  pclose(f);

  if (access(stdcxx_bundle_lib, F_OK) == 0) {
    f = popen("ldconfig -p | grep 'libstdc++.so.6 (" LIBC6_ARCH ")' | awk 'NR==1{print $NF}'", "r");
    ret = fscanf(f, "%s", stdcxx_sys_lib); (void)ret;
    pclose(f);

    if (access(stdcxx_sys_lib, F_OK) == 0) {
      SCANLIB(stdcxx_sys_lib, stdcxx_sys_sym, "^GLIBCXX_3\\.4");
      SCANLIB(stdcxx_bundle_lib, stdcxx_bundle_sym, "^GLIBCXX_3\\.4");
      stdcxx_sys_ver = atoi(stdcxx_sys_sym+12);
      stdcxx_bundle_ver = atoi(stdcxx_bundle_sym+12);
      printf("%s ==> %s (%d)\n", stdcxx_sys_lib, stdcxx_sys_sym, stdcxx_sys_ver);
      printf("%s ==> %s (%d)\n\n", stdcxx_bundle_lib, stdcxx_bundle_sym, stdcxx_bundle_ver);
    }
  }

  if (access(gcc_bundle_lib, F_OK) == 0) {
    f = popen("ldconfig -p | grep 'libgcc_s.so.1 (" LIBC6_ARCH ")' | awk 'NR==1{print $NF}'", "r");
    ret = fscanf(f, "%s", gcc_sys_lib); (void)ret;
    pclose(f);

    if (access(gcc_sys_lib, F_OK) == 0) {
      SCANLIB(gcc_sys_lib, gcc_sys_sym, "^GCC_[0-9]\\.[0-9]");
      SCANLIB(gcc_bundle_lib, gcc_bundle_sym, "^GCC_[0-9]\\.[0-9]");
      gcc_sys_ver = atoi(gcc_sys_sym+4) * 100 + atoi(gcc_sys_sym+6) * 10 + atoi(gcc_sys_sym+8);
      gcc_bundle_ver = atoi(gcc_bundle_sym+4) * 100 + atoi(gcc_bundle_sym+6) * 10 + atoi(gcc_bundle_sym+8);
      printf("%s ==> %s (%d)\n", gcc_sys_lib, gcc_sys_sym, gcc_sys_ver);
      printf("%s ==> %s (%d)\n\n", gcc_bundle_lib, gcc_bundle_sym, gcc_bundle_ver);
    }
  }

#undef SCANLIB

  if (stdcxx_bundle_ver > stdcxx_sys_ver) {
    printf("using bundled libstdc++.so.6\n");
  } else {
    printf("using system libstdc++.so.6\n");
  }

  if (gcc_bundle_ver > gcc_sys_ver) {
    printf("using bundled libgcc_s.so.1\n");
  } else {
    printf("using system libgcc_s.so.1\n");
  }

  return 0;
}