lib/forkpty.c

   1 /* Fork a child process attached to the slave of a pseudo-terminal.
   2    Copyright (C) 2010-2025 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation, either version 3 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <pty.h>
  21
  22 #if HAVE_FORKPTY
  23
  24 /* Provide a wrapper with the prototype of glibc-2.8 and newer.  */
  25 # undef forkpty
  26 int
  27 rpl_forkpty (int *amaster, char *name, struct termios const *termp,
  28          struct winsize const *winp)
  29 {
  30   /* Cast away const, for implementations with weaker prototypes.  */
  31   return forkpty (amaster, name, (struct termios *) termp,
  32                   (struct winsize *) winp);
  33 }
  34
  35 #else /* AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 10, mingw */
  36
  37 # include <pty.h>
  38 # include <unistd.h>
  39
  40 extern int login_tty (int slave_fd);
  41
  42 int
  43 forkpty (int *amaster, char *name,
  44          const struct termios *termp, const struct winsize *winp)
  45 {
  46   int master, slave, pid;
  47
  48   if (openpty (&master, &slave, name, termp, winp) == -1)
  49     return -1;
  50
  51   switch (pid = fork ())
  52     {
  53     case -1:
  54       close (master);
  55       close (slave);
  56       return -1;
  57
  58     case 0:
  59       /* Child.  */
  60       close (master);
  61       if (login_tty (slave))
  62         _exit (1);
  63       return 0;
  64
  65     default:
  66       /* Parent.  */
  67       *amaster = master;
  68       close (slave);
  69       return pid;
  70     }
  71 }
  72
  73 #endif