>From 099cb9f7b8b1d00293298d947fc77b8c96120820 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Thu, 11 Jun 2015 16:41:36 -0700 Subject: [PATCH] Fix "not a tty" bug on Solaris 10 * configure.ac (PTY_OPEN): Define to plain 'open' on SVR4-derived hosts, so that the O_CLOEXEC flag isn't set. * src/process.c (allocate_pty): Set the O_CLOEXEC flag after calling PTY_TTY_NAME_SPRINTF, for the benefit of SVR4-derived hosts that call grantpt which does its work via a setuid subcommand (Bug#19191, Bug#19927, Bug#20555, Bug#20686). Also, set O_CLOEXEC even if PTY_OPEN is not defined, since it seems relevant in that case too. --- configure.ac | 5 ++++- src/process.c | 20 +++++++++++--------- 2 files changed, 15 insertions(+), 10 deletions(-) diff --git a/configure.ac b/configure.ac index 9c6a74a..070b061 100644 --- a/configure.ac +++ b/configure.ac @@ -4397,14 +4397,17 @@ case $opsys in ;; sol2* ) - dnl On SysVr4, grantpt(3) forks a subprocess, so keep sigchld_handler() + dnl On SysVr4, grantpt(3) forks a subprocess, so do not use + dnl O_CLOEXEC when opening the pty, and keep the SIGCHLD handler dnl from intercepting that death. If any child but grantpt's should die dnl within, it should be caught after sigrelse(2). + AC_DEFINE(PTY_OPEN, [fd = open (pty_name, O_RDWR | O_NONBLOCK)]) AC_DEFINE(PTY_TTY_NAME_SPRINTF, [{ char *ptsname (int), *ptyname; int grantpt_result; sigset_t blocked; sigemptyset (&blocked); sigaddset (&blocked, SIGCHLD); pthread_sigmask (SIG_BLOCK, &blocked, 0); grantpt_result = grantpt (fd); pthread_sigmask (SIG_UNBLOCK, &blocked, 0); if (grantpt_result == -1 || unlockpt (fd) == -1 || !(ptyname = ptsname (fd))) { emacs_close (fd); return -1; } snprintf (pty_name, PTY_NAME_SIZE, "%s", ptyname); }]) ;; unixware ) dnl Comments are as per sol2*. + AC_DEFINE(PTY_OPEN, [fd = open (pty_name, O_RDWR | O_NONBLOCK)]) AC_DEFINE(PTY_TTY_NAME_SPRINTF, [{ char *ptsname (int), *ptyname; int grantpt_result; sigset_t blocked; sigemptyset (&blocked); sigaddset (&blocked, SIGCHLD); pthread_sigmask (SIG_BLOCK, &blocked, 0); grantpt_result = grantpt (fd); pthread_sigmask (SIG_UNBLOCK, &blocked, 0); if (grantpt_result == -1) fatal("could not grant slave pty"); if (unlockpt(fd) == -1) fatal("could not unlock slave pty"); if (!(ptyname = ptsname(fd))) fatal ("could not enable slave pty"); snprintf (pty_name, PTY_NAME_SIZE, "%s", ptyname); }]) ;; esac diff --git a/src/process.c b/src/process.c index 17fe708..b4f979f 100644 --- a/src/process.c +++ b/src/process.c @@ -658,22 +658,24 @@ allocate_pty (char pty_name[PTY_NAME_SIZE]) if (fd >= 0) { -#ifdef PTY_OPEN +#ifdef PTY_TTY_NAME_SPRINTF + PTY_TTY_NAME_SPRINTF +#else + sprintf (pty_name, "/dev/tty%c%x", c, i); +#endif /* no PTY_TTY_NAME_SPRINTF */ + /* Set FD's close-on-exec flag. This is needed even if PT_OPEN calls posix_openpt with O_CLOEXEC, since POSIX doesn't require support for that combination. + Do this after PTY_TTY_NAME_SPRINTF, which on some platforms + doesn't work if the close-on-exec flag is set (Bug#20555). Multithreaded platforms where posix_openpt ignores O_CLOEXEC (or where PTY_OPEN doesn't call posix_openpt) have a race condition between the PTY_OPEN and here. */ fcntl (fd, F_SETFD, FD_CLOEXEC); -#endif - /* Check to make certain that both sides are available - this avoids a nasty yet stupid bug in rlogins. */ -#ifdef PTY_TTY_NAME_SPRINTF - PTY_TTY_NAME_SPRINTF -#else - sprintf (pty_name, "/dev/tty%c%x", c, i); -#endif /* no PTY_TTY_NAME_SPRINTF */ + + /* Check to make certain that both sides are available. + This avoids a nasty yet stupid bug in rlogins. */ if (faccessat (AT_FDCWD, pty_name, R_OK | W_OK, AT_EACCESS) != 0) { emacs_close (fd); -- 2.1.0