1. Help with pipe io
- Posted by jbrown1050 at yahoo.com
Mar 28, 2002
--fdj2RfSjLxBAspz7
I'm working on pipes for linux which are full duplex.
However, there is a bug,
as shown in demo1.exu - uncomment out the line which
opens "/bin/echo",
and you'll see that echo outputs a bunch of garbage
instead of "Hello World!"
Can anyone please explain why this happens and how to
fix it?
Thanks in advance.
--
"Is there peace in heaven, or is that merely an
illusion?" - Someone
"May peace find its way through the heavens to the
world of men and women
before the fires of the damned consume them." -
Someone
Linux User:190064
Linux Machine:84163
--fdj2RfSjLxBAspz7
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="cpipe.e"
include dll.e
include machine.e
constant STDLIB = open_dll("")
constant PIPE = define_c_func(STDLIB, "pipe",
{C_POINTER}, C_INT)
constant READ = define_c_func(STDLIB, "read", {C_INT,
C_POINTER, C_INT}, C_INT)
constant WRITE = define_c_func(STDLIB, "write",
{C_INT, C_POINTER, C_INT}, C_INT)
constant CLOSE = define_c_func(STDLIB, "close",
{C_INT}, C_INT)
constant DUP2 = define_c_func(STDLIB, "dup2", {C_INT,
C_INT}, C_INT)
constant KILL = define_c_func(STDLIB, "kill", {C_INT,
C_INT}, C_INT)
constant FORK = define_c_func(STDLIB, "fork", {},
C_INT)
constant EXECV = define_c_func(STDLIB, "execv",
{C_POINTER, C_POINTER}, C_INT)
constant SIGNAL = define_c_func(STDLIB, "signal",
{C_INT, C_POINTER}, C_POINTER)
constant ERRNO = define_c_var(STDLIB, "errno")
global constant os_stdin = 0
global constant os_stdout = 1
global constant os_stderr = 2
global constant os_sig_dfl = 0
global constant os_sig_ign = 1
global atom os_errno os_errno = 0
global object VOID VOID = {}
global function os_pipe()
atom cmd, r, in, out
cmd = allocate(8)
r = c_func(PIPE,{cmd})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
in = peek4u(cmd)
out = peek4u(cmd+4)
free(cmd)
return {in, out}
end function
global function os_read(atom fd, integer bytes)
atom buf, r
sequence data
buf = allocate(bytes)
r = c_func(READ, {fd, buf, bytes})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
if r = 0 then
free(buf)
return ""
end if
data = ""
for i = 1 to r do
data &= peek(buf+i-1)
end for
return data
end function
global function os_write(atom fd, sequence str)
atom buf, r
buf = allocate_string(str)
r = c_func(WRITE, {fd, buf, length(str)})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
return r
end function
global function os_close(atom fd)
atom r
r = c_func(CLOSE, {fd})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
return 0
end function
global function os_dup2(atom oldfd, atom newfd)
atom r
r = c_func(DUP2, {oldfd, newfd})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
return r
end function
global function os_kill(atom pid, atom signal)
atom r
r = c_func(KILL, {pid, signal})
if r = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
return r
end function
global function os_fork()
atom pid
pid = c_func(FORK, {})
if pid = -1 then
os_errno = peek4u(ERRNO)
return -1
end if
return pid
end function
global function os_execv(sequence s, sequence v)
atom sbuf
atom vbuf
atom vbufstr
atom r
sbuf = allocate_string(s)
vbuf = allocate((length(v)+1)*4)
for i = 1 to length(v) do
vbufstr = allocate_string(v[i])
poke4(vbuf+((i-1)*4), vbufstr)
end for
poke4(vbuf+((length(v)+1)*4), 0)
r = c_func(EXECV, {sbuf, vbuf}) -- execv() should
never return
os_errno = peek4u(ERRNO)
return r
end function
global function os_signal(integer signal, atom
handler)
return c_func(SIGNAL, {signal, handler})
end function
--fdj2RfSjLxBAspz7
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="pipeio.e"
include cpipe.e
procedure error()
crash_message(sprintf("Errno = %d", os_errno))
? 1/0
end procedure
global function popen(sequence command, sequence args)
atom pid
sequence ipipe, opipe, epipe
ipipe = {os_pipe()}
opipe = {os_pipe()}
epipe = {os_pipe()}
if atom(ipipe[1]) then
error()
end if
if atom(opipe[1]) then
error()
end if
if atom(epipe[1]) then
error()
end if
ipipe = ipipe[1]
opipe = opipe[1]
epipe = epipe[1]
pid = os_fork()
if pid = 0 then
VOID = os_signal(15, os_sig_dfl) --15 = sigterm
if os_dup2(ipipe[1], os_stdin) = -1 then
error()
end if
if os_dup2(opipe[2], os_stdout) = -1 then
error()
end if
if os_dup2(epipe[2], os_stderr) = -1 then
error()
end if
if os_execv(command, args) then
error()
end if
elsif pid = -1 then
error()
end if
return {pid, ipipe[2], opipe[1], epipe[1]}
end function
--fdj2RfSjLxBAspz7
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="demo1.exu"
with trace
include pipeio.e
sequence data
--data = popen("/opt/euphoria/bin/exu",
{"subprocess1.exu"})
-- eu programs dont work w/ pipes, so use echo to
test instead
--data = popen("/bin/echo", {"Hello World!"})
-- interesting bug, some strange garbage is
printed instead of the message.
data = popen("/bin/arch", {})
-- this seems to work fine
integer pid, pin, pout, perr
pid = data[1]
pin = data[2]
pout = data[3]
perr = data[4]
object c
c = os_read(pout, 256)
if atom(c) then
printf(1, "Failed on read with error %x",
os_errno)
abort(1)
end if
puts(1, c)
VOID = os_kill(pid, 15)
--pclose(pipe)
--fdj2RfSjLxBAspz7
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="demo2.exu"
with trace
include pipeio.e
sequence data
--data = popen("/opt/euphoria/bin/exu",
{"subprocess2.exu"})
-- eu programs dont work w/ pipes, so use cat to
test instead
data = popen("/bin/cat", {})
integer pid, pin, pout, perr
pid = data[1]
pin = data[2]
pout = data[3]
perr = data[4]
object c
c = os_write(pin, "Hello, World!\n")
if c = -1 then
printf(1, "Failed on write with error %x",
os_errno)
abort(1)
end if
c = os_read(pout, 256)
if atom(c) then
printf(1, "Failed on read with error %x",
os_errno)
abort(1)
end if
puts(1, c)
VOID = os_kill(pid, 15)
--pclose(pipe)
--fdj2RfSjLxBAspz7--
2. Re: Help with pipe io
jbrown writes:
> you'll see that echo outputs a bunch of garbage
> instead of "Hello World!"
I'm not sure what your specific problem is,
but on Linux, ncurses has a bug that causes
stderr and stdout to be mixed together.
If stdout from your Euphoria Linux program is redirected
to a file, and your program also tries to print something
to the screen, you may find the screen output plus
a bunch of ncurses control characters mixed into the file.
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
3. Re: Help with pipe io
- Posted by jbrown1050 at yahoo.com
Mar 28, 2002
On 0, Robert Craig <rds at RapidEuphoria.com> wrote:
>
> jbrown writes:
> > you'll see that echo outputs a bunch of garbage
> > instead of "Hello World!"
>
> I'm not sure what your specific problem is,
> but on Linux, ncurses has a bug that causes
> stderr and stdout to be mixed together.
> If stdout from your Euphoria Linux program is
redirected
> to a file, and your program also tries to print
something
> to the screen, you may find the screen output plus
> a bunch of ncurses control characters mixed into the
file.
>
> Regards,
> Rob Craig
> Rapid Deployment Software
> http://www.RapidEuphoria.com
>
Thanks, but thats not my exact problem. I get garbage
when i call and redirect
any program which uses arguments. I think its a
problem with the way I'm
setting up the array.
BTW, What I'm trying to do is redirect stdin, stdout,
and stderr of a program
to pipes for interprocess communication, just in case
someone else has figured
this out already. (I know about filelib.e and
pipelib.e by the way, and
Jeffrey Fielding has done a very good job with them,
but I want full duplex,
not half-duplex, pipe io.)
--
