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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <errno.h>
     30 #include <fcntl.h>
     31 #include <stdio.h>
     32 #include <stdlib.h>
     33 #include <sys/ioctl.h>
     34 #include <termios.h>
     35 #include <unistd.h>
     36 
     37 int getpt(void) {
     38   return posix_openpt(O_RDWR|O_NOCTTY);
     39 }
     40 
     41 int grantpt(int) {
     42   return 0;
     43 }
     44 
     45 int posix_openpt(int flags) {
     46   return open("/dev/ptmx", flags);
     47 }
     48 
     49 char* ptsname(int fd) {
     50   static char buf[64];
     51   return ptsname_r(fd, buf, sizeof(buf)) == 0 ? buf : NULL;
     52 }
     53 
     54 int ptsname_r(int fd, char* buf, size_t len) {
     55   if (buf == NULL) {
     56     errno = EINVAL;
     57     return errno;
     58   }
     59 
     60   unsigned int pty_num;
     61   if (ioctl(fd, TIOCGPTN, &pty_num) != 0) {
     62     errno = ENOTTY;
     63     return errno;
     64   }
     65 
     66   if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= static_cast<int>(len)) {
     67     errno = ERANGE;
     68     return errno;
     69   }
     70 
     71   return 0;
     72 }
     73 
     74 char* ttyname(int fd) {
     75   static char buf[64];
     76   return ttyname_r(fd, buf, sizeof(buf)) == 0 ? buf : NULL;
     77 }
     78 
     79 int ttyname_r(int fd, char* buf, size_t len) {
     80   if (buf == NULL) {
     81     errno = EINVAL;
     82     return errno;
     83   }
     84 
     85   if (!isatty(fd)) {
     86     return errno;
     87   }
     88 
     89   char path[64];
     90   snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
     91 
     92   ssize_t count = readlink(path, buf, len);
     93   if (count == -1) {
     94     return errno;
     95   }
     96   if (static_cast<size_t>(count) == len) {
     97     errno = ERANGE;
     98     return errno;
     99   }
    100   buf[count] = '\0';
    101   return 0;
    102 }
    103 
    104 int unlockpt(int fd) {
    105   int unlock = 0;
    106   return ioctl(fd, TIOCSPTLCK, &unlock);
    107 }
    108