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/* $OpenBSD: posix_pty.c,v 1.2 2015/05/11 00:42:54 guenther Exp $ */ |
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/* |
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* Copyright (c) 2012 Todd C. Miller <Todd.Miller@courtesan.com> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/types.h> |
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#include <sys/ioctl.h> |
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#include <sys/stat.h> |
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#include <sys/tty.h> |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <paths.h> |
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#include <stddef.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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int |
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posix_openpt(int oflag) |
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{ |
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struct ptmget ptm; |
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int fd, mfd = -1; |
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/* User must specify O_RDWR in oflag. */ |
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if ((oflag & O_ACCMODE) != O_RDWR || |
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(oflag & ~(O_ACCMODE | O_NOCTTY)) != 0) { |
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errno = EINVAL; |
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return -1; |
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} |
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/* Get pty master and slave (this API only uses the master). */ |
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fd = open(PATH_PTMDEV, O_RDWR); |
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if (fd != -1) { |
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if (ioctl(fd, PTMGET, &ptm) != -1) { |
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close(ptm.sfd); |
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mfd = ptm.cfd; |
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} |
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close(fd); |
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} |
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return mfd; |
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} |
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/* |
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* Look up the name of the specified pty master fd. |
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* Note that the name returned does *not* include the /dev/ prefix. |
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* Returns the name on success and NULL on error, setting errno. |
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*/ |
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static const char * |
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ptmname(int mfd) |
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{ |
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struct stat sb; |
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const char *name; |
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/* Make sure it is a pty master. */ |
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if (fstat(mfd, &sb) != 0) |
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return NULL; |
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if (!S_ISCHR(sb.st_mode)) { |
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errno = EINVAL; |
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return NULL; |
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} |
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name = devname(sb.st_rdev, S_IFCHR); |
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if (strncmp(name, "pty", 3) != 0) { |
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errno = EINVAL; |
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return NULL; |
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} |
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return name; |
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} |
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/* |
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* The PTMGET ioctl handles the mode and owner for us. |
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*/ |
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int |
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grantpt(int mfd) |
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{ |
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return ptmname(mfd) ? 0 : -1; |
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} |
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/* |
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* The PTMGET ioctl unlocks the pty master and slave for us. |
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*/ |
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int |
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unlockpt(int mfd) |
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{ |
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return ptmname(mfd) ? 0 : -1; |
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} |
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/* |
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* Look up the path of the slave pty that corresponds to the master fd. |
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* Returns the path if successful or NULL on error. |
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*/ |
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char * |
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ptsname(int mfd) |
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{ |
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const char *master; |
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static char slave[sizeof(((struct ptmget *)NULL)->sn)]; |
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if ((master = ptmname(mfd)) == NULL) |
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return NULL; |
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/* Add /dev/ prefix and convert "pty" to "tty". */ |
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strlcpy(slave, _PATH_DEV, sizeof(slave)); |
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strlcat(slave, master, sizeof(slave)); |
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slave[sizeof(_PATH_DEV) - 1] = 't'; |
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return slave; |
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} |