110 lines
2.8 KiB
C
110 lines
2.8 KiB
C
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/* Open a pseudoterminal.
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Copyright (C) 2018-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <support/tty.h>
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#include <support/check.h>
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#include <support/support.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <sys/ioctl.h>
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#include <unistd.h>
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/* As ptsname, but allocates space for an appropriately-sized string
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using malloc. */
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static char *
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xptsname (int fd)
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{
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int rv;
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size_t buf_len = 128;
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char *buf = xmalloc (buf_len);
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for (;;)
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{
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rv = ptsname_r (fd, buf, buf_len);
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if (rv)
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FAIL_EXIT1 ("ptsname_r: %s", strerror (errno));
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if (memchr (buf, '\0', buf_len))
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return buf; /* ptsname succeeded and the buffer was not truncated */
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buf_len *= 2;
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buf = xrealloc (buf, buf_len);
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}
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}
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void
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support_openpty (int *a_outer, int *a_inner, char **a_name,
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const struct termios *termp,
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const struct winsize *winp)
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{
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int outer = -1, inner = -1;
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char *namebuf = 0;
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outer = posix_openpt (O_RDWR | O_NOCTTY);
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if (outer == -1)
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FAIL_EXIT1 ("posix_openpt: %s", strerror (errno));
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if (grantpt (outer))
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FAIL_EXIT1 ("grantpt: %s", strerror (errno));
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if (unlockpt (outer))
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FAIL_EXIT1 ("unlockpt: %s", strerror (errno));
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#ifdef TIOCGPTPEER
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inner = ioctl (outer, TIOCGPTPEER, O_RDWR | O_NOCTTY);
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#endif
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if (inner == -1)
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{
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/* The kernel might not support TIOCGPTPEER, fall back to open
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by name. */
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namebuf = xptsname (outer);
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inner = open (namebuf, O_RDWR | O_NOCTTY);
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if (inner == -1)
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FAIL_EXIT1 ("%s: %s", namebuf, strerror (errno));
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}
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if (termp)
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{
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if (tcsetattr (inner, TCSAFLUSH, termp))
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FAIL_EXIT1 ("tcsetattr: %s", strerror (errno));
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}
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#ifdef TIOCSWINSZ
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if (winp)
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{
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if (ioctl (inner, TIOCSWINSZ, winp))
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FAIL_EXIT1 ("TIOCSWINSZ: %s", strerror (errno));
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}
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#endif
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if (a_name)
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{
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if (!namebuf)
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namebuf = xptsname (outer);
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*a_name = namebuf;
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}
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else
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free (namebuf);
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*a_outer = outer;
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*a_inner = inner;
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}
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