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glibc  2.9
Functions
ttyname_r.c File Reference
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio-common/_itoa.h>
#include <kernel-features.h>

Go to the source code of this file.

Functions

static int getttyname_r (char *buf, size_t buflen, dev_t mydev, ino64_t myino, int save, int *dostat) internal_function
int __ttyname_r (int fd, char *buf, size_t buflen)

Function Documentation

int __ttyname_r ( int  fd,
char *  buf,
size_t  buflen 
)

Definition at line 98 of file ttyname_r.c.

{
  char procname[30];
  struct stat64 st, st1;
  int dostat = 0;
  int save = errno;

  /* Test for the absolute minimal size.  This makes life easier inside
     the loop.  */
  if (!buf)
    {
      __set_errno (EINVAL);
      return EINVAL;
    }

  if (buflen < sizeof ("/dev/pts/"))
    {
      __set_errno (ERANGE);
      return ERANGE;
    }

  /* isatty check, tcgetattr is used because it sets the correct
     errno (EBADF resp. ENOTTY) on error.  */
  struct termios term;
  if (__builtin_expect (__tcgetattr (fd, &term) < 0, 0))
    return errno;

  /* We try using the /proc filesystem.  */
  *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';

  ssize_t ret = __readlink (procname, buf, buflen - 1);
  if (__builtin_expect (ret == -1 && errno == ENOENT, 0))
    {
      __set_errno (EBADF);
      return EBADF;
    }

  if (__builtin_expect (ret == -1 && errno == ENAMETOOLONG, 0))
    {
      __set_errno (ERANGE);
      return ERANGE;
    }

  if (__builtin_expect (ret != -1
#ifndef __ASSUME_PROC_SELF_FD_SYMLINK
                     /* This is for Linux 2.0.  */
                     && buf[0] != '['
#endif
                     , 1))
    {
      buf[ret] = '\0';
      return 0;
    }

  if (__fxstat64 (_STAT_VER, fd, &st) < 0)
    return errno;

  /* Prepare the result buffer.  */
  memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
  buflen -= sizeof ("/dev/pts/") - 1;

  if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
    {
#ifdef _STATBUF_ST_RDEV
      ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
                       &dostat);
#else
      ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
                       &dostat);
#endif
    }
  else
    {
      __set_errno (save);
      ret = ENOENT;
    }

  if (ret && dostat != -1)
    {
      buf[sizeof ("/dev/") - 1] = '\0';
      buflen += sizeof ("pts/") - 1;
#ifdef _STATBUF_ST_RDEV
      ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
                       &dostat);
#else
      ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
                       &dostat);
#endif
    }

  if (ret && dostat != -1)
    {
      buf[sizeof ("/dev/") - 1] = '\0';
      dostat = 1;
#ifdef _STATBUF_ST_RDEV
      ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino,
                       save, &dostat);
#else
      ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino,
                       save, &dostat);
#endif
    }

  return ret;
}

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static int internal_function attribute_compat_text_section getttyname_r ( char *  buf,
size_t  buflen,
dev_t  mydev,
ino64_t  myino,
int  save,
int dostat 
) [static]

Definition at line 39 of file ttyname_r.c.

{
  struct stat64 st;
  DIR *dirstream;
  struct dirent64 *d;
  size_t devlen = strlen (buf);

  dirstream = __opendir (buf);
  if (dirstream == NULL)
    {
      *dostat = -1;
      return errno;
    }

  while ((d = __readdir64 (dirstream)) != NULL)
    if ((d->d_fileno == myino || *dostat)
       && strcmp (d->d_name, "stdin")
       && strcmp (d->d_name, "stdout")
       && strcmp (d->d_name, "stderr"))
      {
       char *cp;
       size_t needed = _D_EXACT_NAMLEN (d) + 1;

       if (needed > buflen)
         {
           *dostat = -1;
           (void) __closedir (dirstream);
           __set_errno (ERANGE);
           return ERANGE;
         }

       cp = __stpncpy (buf + devlen, d->d_name, needed);
       cp[0] = '\0';

       if (__xstat64 (_STAT_VER, buf, &st) == 0
#ifdef _STATBUF_ST_RDEV
           && S_ISCHR (st.st_mode) && st.st_rdev == mydev
#else
           && d->d_fileno == myino && st.st_dev == mydev
#endif
          )
         {
           (void) __closedir (dirstream);
           __set_errno (save);
           return 0;
         }
      }

  (void) __closedir (dirstream);
  __set_errno (save);
  /* It is not clear what to return in this case.  `isatty' says FD
     refers to a TTY but no entry in /dev has this inode.  */
  return ENOTTY;
}

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