src/unistd/ttyname_r.c

   1 #include <unistd.h>
   2 #include <errno.h>
   3 #include <sys/stat.h>
   4 #include "syscall.h"
   5
   6 int ttyname_r(int fd, char *name, size_t size)
   7 {
   8         struct stat st1, st2;
   9         char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2];
  10         ssize_t l;
  11
  12         if (!isatty(fd)) return errno;
  13
  14         __procfdname(procname, fd);
  15         l = readlink(procname, name, size);
  16
  17         if (l < 0) return errno;
  18         else if (l == size) return ERANGE;
  19
  20         name[l] = 0;
  21
  22         if (stat(name, &st1) || fstat(fd, &st2))
  23                 return errno;
  24         if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
  25                 return ENODEV;
  26
  27         return 0;
  28 }