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Creates and managed pseudo terminals (PTYs). See also en.wikipedia.org/wiki/Pseudo_terminal
PTY allows you to allocate new terminals using ::open or ::spawn a new terminal with a specific command.
In this example we will change the buffering type in the
factor
command, assuming that factor uses stdio for stdout
buffering.
If IO.pipe is used instead of ::open, this code deadlocks because factor's stdout is fully buffered.
# start by requiring the standard library PTY require 'pty' master, slave = PTY.open read, write = IO.pipe pid = spawn("factor", :in=>read, :out=>slave) read.close # we dont need the read slave.close # or the slave # pipe "42" to the factor command write.puts "42" # output the response from factor p master.gets #=> "42: 2 3 7\n" # pipe "144" to factor and print out the response write.puts "144" p master.gets #=> "144: 2 2 2 2 3 3\n" write.close # close the pipe # The result of read operation when pty slave is closed is platform # dependent. ret = begin m.gets # FreeBSD returns nil. rescue Errno::EIO # GNU/Linux raises EIO. nil end p ret #=> nil
C) Copyright 1998 by Akinori Ito. This software may be redistributed freely for this purpose, in full or in part, provided that this entire copyright notice is included on any copies of this software and applications and derivations thereof. This software is provided on an "as is" basis, without warranty of any kind, either expressed or implied, as to any matter including, but not limited to warranty of fitness of purpose, or merchantability, or results obtained from use of this software.
Checks the status of the child process specified by pid
.
Returns nil
if the process is still alive.
If the process is not alive, and raise
was true, a PTY::ChildExited exception will be raised.
Otherwise it will return a Process::Status instance.
pid
The process id of the process to check
raise
If true
and the process identified by pid
is no
longer alive a PTY::ChildExited is
raised.
static VALUE pty_check(int argc, VALUE *argv, VALUE self) { VALUE pid, exc; pid_t cpid; int status; rb_scan_args(argc, argv, "11", &pid, &exc); cpid = rb_waitpid(NUM2PIDT(pid), &status, WNOHANG|WUNTRACED); if (cpid == -1 || cpid == 0) return Qnil; if (!RTEST(exc)) return rb_last_status_get(); raise_from_check(cpid, status); UNREACHABLE; }
Spawns the specified command on a newly allocated pty. You can also use the alias ::getpty.
The command's controlling tty is set to the slave device of the pty and its standard input/output/error is redirected to the slave device.
command
and command_line
are the full commands to
run, given a String. Any additional arguments
will be passed
to the command.
In the non-block form this returns an array of size three, [r, w,
pid]
.
In the block form these same values will be yielded to the block:
r
A readable IO that that contains the command's standard output and standard error
w
A writable IO that is the command's standard input
pid
The process identifier for the command.
static VALUE pty_getpty(int argc, VALUE *argv, VALUE self) { VALUE res; struct pty_info info; rb_io_t *wfptr,*rfptr; VALUE rport = rb_obj_alloc(rb_cFile); VALUE wport = rb_obj_alloc(rb_cFile); char SlaveName[DEVICELEN]; MakeOpenFile(rport, rfptr); MakeOpenFile(wport, wfptr); establishShell(argc, argv, &info, SlaveName); rfptr->mode = rb_io_mode_flags("r"); rfptr->fd = info.fd; rfptr->pathv = rb_obj_freeze(rb_str_new_cstr(SlaveName)); wfptr->mode = rb_io_mode_flags("w") | FMODE_SYNC; wfptr->fd = rb_cloexec_dup(info.fd); if (wfptr->fd == -1) rb_sys_fail("dup()"); rb_update_max_fd(wfptr->fd); wfptr->pathv = rfptr->pathv; res = rb_ary_new2(3); rb_ary_store(res,0,(VALUE)rport); rb_ary_store(res,1,(VALUE)wport); rb_ary_store(res,2,PIDT2NUM(info.child_pid)); if (rb_block_given_p()) { rb_ensure(rb_yield, res, pty_detach_process, (VALUE)&info); return Qnil; } return res; }
Allocates a pty (pseudo-terminal).
In the block form, yields two arguments master_io, slave_file
and the value of the block is returned from open
.
The IO and File are both closed after the block completes if they haven't been already closed.
PTY.open {|master, slave| p master #=> #<IO:masterpty:/dev/pts/1> p slave #=> #<File:/dev/pts/1> p slave.path #=> "/dev/pts/1" }
In the non-block form, returns a two element array, [master_io,
slave_file]
.
master, slave = PTY.open # do something with master for IO, or the slave file
The arguments in both forms are:
master_io
the master of the pty, as an IO.
slave_file
the slave of the pty, as a File. The path to the terminal device is
available via slave_file.path
static VALUE pty_open(VALUE klass) { int master_fd, slave_fd; char slavename[DEVICELEN]; VALUE master_io, slave_file; rb_io_t *master_fptr, *slave_fptr; VALUE assoc; getDevice(&master_fd, &slave_fd, slavename, 1); master_io = rb_obj_alloc(rb_cIO); MakeOpenFile(master_io, master_fptr); master_fptr->mode = FMODE_READWRITE | FMODE_SYNC | FMODE_DUPLEX; master_fptr->fd = master_fd; master_fptr->pathv = rb_obj_freeze(rb_sprintf("masterpty:%s", slavename)); slave_file = rb_obj_alloc(rb_cFile); MakeOpenFile(slave_file, slave_fptr); slave_fptr->mode = FMODE_READWRITE | FMODE_SYNC | FMODE_DUPLEX | FMODE_TTY; slave_fptr->fd = slave_fd; slave_fptr->pathv = rb_obj_freeze(rb_str_new_cstr(slavename)); assoc = rb_assoc_new(master_io, slave_file); if (rb_block_given_p()) { return rb_ensure(rb_yield, assoc, pty_close_pty, assoc); } return assoc; }
Spawns the specified command on a newly allocated pty. You can also use the alias ::getpty.
The command's controlling tty is set to the slave device of the pty and its standard input/output/error is redirected to the slave device.
command
and command_line
are the full commands to
run, given a String. Any additional arguments
will be passed
to the command.
In the non-block form this returns an array of size three, [r, w,
pid]
.
In the block form these same values will be yielded to the block:
r
A readable IO that that contains the command's standard output and standard error
w
A writable IO that is the command's standard input
pid
The process identifier for the command.
static VALUE pty_getpty(int argc, VALUE *argv, VALUE self) { VALUE res; struct pty_info info; rb_io_t *wfptr,*rfptr; VALUE rport = rb_obj_alloc(rb_cFile); VALUE wport = rb_obj_alloc(rb_cFile); char SlaveName[DEVICELEN]; MakeOpenFile(rport, rfptr); MakeOpenFile(wport, wfptr); establishShell(argc, argv, &info, SlaveName); rfptr->mode = rb_io_mode_flags("r"); rfptr->fd = info.fd; rfptr->pathv = rb_obj_freeze(rb_str_new_cstr(SlaveName)); wfptr->mode = rb_io_mode_flags("w") | FMODE_SYNC; wfptr->fd = rb_cloexec_dup(info.fd); if (wfptr->fd == -1) rb_sys_fail("dup()"); rb_update_max_fd(wfptr->fd); wfptr->pathv = rfptr->pathv; res = rb_ary_new2(3); rb_ary_store(res,0,(VALUE)rport); rb_ary_store(res,1,(VALUE)wport); rb_ary_store(res,2,PIDT2NUM(info.child_pid)); if (rb_block_given_p()) { rb_ensure(rb_yield, res, pty_detach_process, (VALUE)&info); return Qnil; } return res; }