diff options
Diffstat (limited to 'libc/stdlib/ptsname.c')
| -rw-r--r-- | libc/stdlib/ptsname.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/libc/stdlib/ptsname.c b/libc/stdlib/ptsname.c new file mode 100644 index 000000000..2fbc6be49 --- /dev/null +++ b/libc/stdlib/ptsname.c @@ -0,0 +1,171 @@ +/* Copyright (C) 1998 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <errno.h> +#include <paths.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/stat.h> +#include <sys/sysmacros.h> +#include <termios.h> +#include <unistd.h> + +/* Check if DEV corresponds to a master pseudo terminal device. */ +#define MASTER_P(Dev) \ + (major ((Dev)) == 2 \ + || (major ((Dev)) == 4 && minor ((Dev)) >= 128 && minor ((Dev)) < 192) \ + || (major ((Dev)) >= 128 && major ((Dev)) < 136)) + +/* Check if DEV corresponds to a master pseudo terminal device. */ +#define SLAVE_P(Dev) \ + (major ((Dev)) == 3 \ + || (major ((Dev)) == 4 && minor ((Dev)) >= 192 && minor ((Dev)) < 256) \ + || (major ((Dev)) >= 136 && major ((Dev)) < 144)) + +/* Note that major number 4 corresponds to the old BSD style pseudo + terminal devices. As of Linux 2.1.115 these are no longer + supported. They have been replaced by major numbers 2 (masters) + and 3 (slaves). */ + +/* Directory where we can find the slave pty nodes. */ +#define _PATH_DEVPTS "/dev/pts/" + +/* The are declared in getpt.c. */ +extern const char _ptyname1[]; +extern const char _ptyname2[]; + +/* Static buffer for `ptsname'. */ +static char buffer[sizeof (_PATH_DEVPTS) + 20]; + +/* +extern char * +_itoa_word (unsigned long value, char *buflim, + unsigned int base, int upper_case); +*/ + + +/* Store at most BUFLEN characters of the pathname of the slave pseudo + terminal associated with the master FD is open on in BUF. + Return 0 on success, otherwise an error number. */ +int ptsname_r (int fd, char *buf, size_t buflen) +{ + int save_errno = errno; + struct stat st; + int ptyno; + + if (buf == NULL) + { + errno = EINVAL; + return EINVAL; + } + + if (!isatty (fd)) + { + errno = ENOTTY; + return ENOTTY; + } +#if 0 +#ifdef TIOCGPTN + if (ioctl (fd, TIOCGPTN, &ptyno) == 0) + { + /* Buffer we use to print the number in. For a maximum size for + `int' of 8 bytes we never need more than 20 digits. */ + char numbuf[21]; + const char *devpts = _PATH_DEVPTS; + const size_t devptslen = strlen (devpts); + char *p; + + numbuf[20] = '\0'; + p = _itoa_word (ptyno, &numbuf[20], 10, 0); + + if (buflen < devptslen + strlen (p) + 1) + { + errno = ERANGE; + return ERANGE; + } + + strcpy (buf, devpts); + strcat (buf, p); + } + else if (errno == EINVAL) +#endif +#endif + { + char *p; + + if (buflen < strlen (_PATH_TTY) + 3) + { + errno = ERANGE; + return ERANGE; + } + + if (fstat (fd, &st) < 0) + return errno; + + /* Check if FD really is a master pseudo terminal. */ + if (! MASTER_P (st.st_rdev)) + { + errno = ENOTTY; + return ENOTTY; + } + + ptyno = minor (st.st_rdev); + /* This is for the old BSD pseudo terminals. As of Linux + 2.1.115 these are no longer supported. */ + if (major (st.st_rdev) == 4) + ptyno -= 128; + + if (ptyno / 16 >= strlen (_ptyname1)) + { + errno = ENOTTY; + return ENOTTY; + } + + strcpy (buf, _PATH_TTY); + p = buf + strlen (buf); + p[0] = _ptyname1[ptyno / 16]; + p[1] = _ptyname2[ptyno % 16]; + p[2] = '\0'; + } + + if (_xstat (_STAT_VER, buf, &st) < 0) + return errno; + + /* Check if the name we're about to return really corresponds to a + slave pseudo terminal. */ + if (! S_ISCHR (st.st_mode) || ! SLAVE_P (st.st_rdev)) + { + /* This really is a configuration problem. */ + errno = ENOTTY; + return ENOTTY; + } + + errno = save_errno; + return 0; +} + +/* Return the pathname of the pseudo terminal slave assoicated with + the master FD is open on, or NULL on errors. + The returned storage is good until the next call to this function. */ +char * +ptsname (int fd) +{ + return ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer; +} |