src/system/libroot/posix/unistd/ttyname.c

   1 /*
   2  * Copyright 2003, Daniel Reinhold, danielre@users.sf.net. All rights reserved.
   3  * Copyright 2007, François Revol, mmu_man@users.sf.net. All rights reserved.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7
   8 #include <SupportDefs.h>
   9 #include <Drivers.h>
  10
  11 #include <errno.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <sys/stat.h>
  16 #include <sys/param.h>
  17
  18 #include <errno_private.h>
  19
  20
  21 /**
  22  * give the name of a tty fd. threadsafe.
  23  * @param fd the tty to get the name from.
  24  * @param buffer where to store the name to.
  25  * @param bufferSize length of the buffer.
  26  * @return 0 on success, -1 on error, sets errno.
  27  */
  28 int
  29 ttyname_r(int fd, char *buffer, size_t bufferSize)
  30 {
  31         struct stat fdStat;
  32
  33         // first, some sanity checks:
  34         if (fstat(fd, &fdStat) < 0)
  35                 return ENOTTY;
  36
  37         if (!S_ISCHR(fdStat.st_mode) || !isatty(fd))
  38                 return ENOTTY;
  39
  40         // just ask devfs
  41         if (ioctl(fd, B_GET_PATH_FOR_DEVICE, buffer, bufferSize) < 0)
  42                 return errno;
  43         return 0;
  44 }
  45
  46
  47 /**
  48  * give the name of a tty fd.
  49  * @param fd the tty to get the name from.
  50  * @return the name of the tty or NULL on error.
  51  */
  52 char *
  53 ttyname(int fd)
  54 {
  55         static char pathname[MAXPATHLEN];
  56
  57         int err = ttyname_r(fd, pathname, sizeof(pathname));
  58         if (err != 0) {
  59                 __set_errno(err);
  60                 return NULL;
  61         }
  62         return pathname;
  63 }