UNIX 7th Ed. - /usr/src/libc/gen/ttyname.c

   1: /*
   2:  * ttyname(f): return "/dev/ttyXX" which the the name of the
   3:  * tty belonging to file f.
   4:  *  NULL if it is not a tty
   5:  */
   6: 
   7: #define NULL    0
   8: #include <sys/types.h>
   9: #include <sys/dir.h>
  10: #include <sys/stat.h>
  11: 
  12: static  char    dev[]   = "/dev/";
  13: char    *strcpy();
  14: char    *strcat();
  15: 
  16: char *
  17: ttyname(f)
  18: {
  19:     struct stat fsb;
  20:     struct stat tsb;
  21:     struct direct db;
  22:     static char rbuf[32];
  23:     register df;
  24: 
  25:     if (isatty(f)==0)
  26:         return(NULL);
  27:     if (fstat(f, &fsb) < 0)
  28:         return(NULL);
  29:     if ((fsb.st_mode&S_IFMT) != S_IFCHR)
  30:         return(NULL);
  31:     if ((df = open(dev, 0)) < 0)
  32:         return(NULL);
  33:     while (read(df, (char *)&db, sizeof(db)) == sizeof(db)) {
  34:         if (db.d_ino == 0)
  35:             continue;
  36:         if (db.d_ino != fsb.st_ino)
  37:             continue;
  38:         strcpy(rbuf, dev);
  39:         strcat(rbuf, db.d_name);
  40:         if (stat(rbuf, &tsb) < 0)
  41:             continue;
  42:         if (tsb.st_dev==fsb.st_dev && tsb.st_ino==fsb.st_ino) {
  43:             close(df);
  44:             return(rbuf);
  45:         }
  46:     }
  47:     close(df);
  48:     return(NULL);
  49: }

Defined functions

Defined variables

Defined macros