#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>

static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

int strerror_r(int errnum, char *strerrbuf, size_t buflen) {
   char *buf;
   int error1;
   int error2;
   int error3;
   sigset_t maskblock;
   sigset_t maskold;

   if ((sigfillset(&maskblock)== -1) ||
       (sigprocmask(SIG_SETMASK, &maskblock, &maskold) == -1))
      return errno;
   if (error1 = pthread_mutex_lock(&lock)) {
      (void)sigprocmask(SIG_SETMASK, &maskold, NULL);
      return error1;
   }
   buf = strerror(errnum);
   if (strlen(buf) >= buflen)
      error1 = ERANGE;
   else 
      (void *)strcpy(strerrbuf, buf);
   error2 = pthread_mutex_unlock(&lock);
   error3 = sigprocmask(SIG_SETMASK, &maskold, NULL);
   return error1 ? error1 : (error2 ? error2 : error3);
}

int perror_r(const char *s) {
   int error1;
   int error2;
   sigset_t maskblock;
   sigset_t maskold;
 
   if ((sigfillset(&maskblock) == -1) ||
       (sigprocmask(SIG_SETMASK, &maskblock, &maskold) == -1))
      return errno;
   if (error1 = pthread_mutex_lock(&lock)) {
      (void)sigprocmask(SIG_SETMASK, &maskold, NULL);
      return error1;
   }
   perror(s);
   error1 = pthread_mutex_unlock(&lock);
   error2 = sigprocmask(SIG_SETMASK, &maskold, NULL);
   return error1 ? error1 : error2;
}